CYANEX272 Extractant

Solvent Extraction Reagent

Selective for cobalt over nickel from sulfate and chloride media.

Selective for zinc in the

presence of calcium and cobalt.

Extracts other metal

cations.

CONTENTS INTRODUCTION Chemical Structure 2 Typical Properties 2 Stability 2 Solubility Losses 3 Toxicity 3 Suitability of Construction Materials 3 COBALT RECOVERY Cobalt-Nickel Selectivity 4 Sulfate Solution (Table 1) 4 Chloride Solution (Table 2) 4 Calcium Rejection 5 Cobalt Extraction Isotherm 5 Cobalt Loading 5 Scrubbing Isotherm 6 Stripping Isotherms 6 Using H2SO4 (Table 7) 6 Using HCl (Table 8) 6

Continuous Separation of Cobalt from Nickel in Sulfate Solution 6 Effect of Process Variables on Cobalt-Nickel Separation Factor 7 Effect of Temperature (Table 9) 8 Effect of Equilibrium pH (Table 10) 8 Effect of Diluent Aromaticity (Table 11) 8 Effect of Phase Modifier (Table 12) 8 OTHER POTENTIAL APPLICATIONS Diluent Oxidation and Prevention 9 Recovery from Ammoniacal Solutions (Table 13) 9 Extraction from Single Metal Sulfate Solutions (Table 14) 9 Extraction from Single Metal Chloride Solutions (Table 15) 10 ANALYTICAL METHODS In Organic Solvents 13 In Aqueous Solutions 15 TECHNICAL PAPERS AND PATENTS Technical Papers 16 Patents 31 HEALTH AND SAFETY 35

1

2

INTRODUCTION CYANEX 272 extractant has proven to be the reagent of choice for the separation of cobalt from nickel from both sulfate and chloride media. It is now being used to produce a major portion of the world's cobalt. Since the active component of CYANEX 272 extractant is a phosphinic acid, metals are extracted through a cation exchange mechanism. Although CYANEX 272 extractant is selective for cobalt in the presence of nickel, a variety of other cations can also be extracted depending upon the solution pH. CYANEX 272 extractant is totally miscible with common aromatic and aliphatic diluents, and is extremely stable to both heat and hydrolysis.

Chemical Structure The active component of CYANEX 272 extractant is bis(2,4,4-trimethylpentyl)phosphinic acid. Typical Properties

Bis(2,4,4-trimethylpentyl)phosphinic acid : 85% Appearance : Colourless to light amber liquid Specific Gravity at 24oC : 0.92 Viscosity, Brookfield at 25oC : 142cp 50oC : 37cp Solubility in distilled H2O at pH 2.6 : 16 g/ml pH 3.7 : 38g/mL Boiling Point : >300oC Pour Point : -32oC Flash Point, closed cup : >108oC Specific Heat @ 52oC : 0.48 cal/gm/oC Thermal Conductivity : 2.7 x 10-4 cal/cm/sec/oC Stability The hydrolytic stability of CYANEX 272 extractant was examined in several tests which involved equilibrating the reagent with aqueous cobalt-nickel sulfate solutions at pH 5 and 50oC. The experimental procedure involved contacting the aqueous and organic phases in a stirred vessel for one week and then stripping the organic phase with sulfuric acid. The solvent was subsequently returned to the vessel for a further one week contact with a fresh aqueous solution. The procedure was repeated for a total contact time of four weeks. Analysis by titration and 31P NMR failed to detect any degradation of the reagent, nor were any statistically significant changes in cobalt-nickel selectivity observed. Furthermore, no degradation has been detected in plants which have been operating continuously for as long as ten years.

CH3 C CH2 CH CH2

CH3

CH3 CH3

CH3 C CH2 CH CH2

CH3

CH3

CH3

P

OH

O

CAS Number: 83411-71-6

3

Solubility Losses Losses of CYANEX 272 extractant by distribution to aqueous cobalt-nickel sulfate solutions were determined in a number of shake-out tests. The effect of two variables, pH and aqueous phase salt concentration, was studied. Aliquots of the organic and aqueous phases were contacted for 5 minutes at 50oC and A/O = 1. After coalesence, the aqueous phases were analyzed for CYANEX 272 extractant using a gas chromatographic procedure. The solvent was composed of 12 v/o CYANEX 272 extractant in Kermac* 470B diluent. Ammonium hydroxide was used for pH adjustment. The results of the extractant solubility (truly dissolved data) are given below.

Aqueous Composition (g/l) CYANEX 272 Ni Co Total Salt Equilibrium Extractant Conc. pH Solubility (g/ml)

100 2 300 3-5 0.5-1.5 25 25 133 4.6 2 5.3 2 6.2 2 5 5 27 4.6 3 5.5 8 6.5 25

The solubility losses follow the general pattern expected of an acidic extractant. Distribution to the aqueous phase was found to be proportional to pH and inversely proportional to salt concentration. As can be seen, the losses are not excessive and this is corroborated by operating plant experience where total annual losses from both solubility and entrainment are approximately 10-15% of the solvent inventory. Toxicity The acute oral (rat) and acute dermal (rabbit) LD50 values for CYANEX 272 extractant are >3.5 g/kg and >2.0 g/kg, respectively. The product produced only limited to mild eye and ski irritation during primary irritation studies with rabbits. The acute LC50, (96 hr) for the bluegill sunfish and rainbow trout are 46 mg/L and 22 mg/L, respectively. When CYANEX 272 extractant was assayed for mutagenic potential in the Ames Salmonella Test, it was determined to be non-mutagenic. CYANEX 272 extractant is considered as a non-toxic material. * A product of Kerr McGee Refining Corp.

Suitability of Construction Materials Metals: Samples of stainless steel (304 and 316), mild steel and aluminum in the form of coupons (approximate dimensions 50mm x 20mm x 3mm) were immersed in capped jars for 8-1/2 months at 50oC (temperature was maintained only during working hours). No corrosion was observed in the three steel samples but aluminum exhibited minimal corrosion at a rate of 1 mil/year. Plastics and Rubbers: Samples of various plastics and rubbers were immersed in CYANEX 272 extractant and kept at 50oC for a total of 424 hours. The following observations were made: Material Remarks Butyl Rubber Unsuitable. Increase in

dimensions and softening. Teflon Fluorocarbon Film** Suitable. No measured effect. Polypropylene Suitable. No measured effect. Natural and Black Latex Unsuitable. Complete dissolution

in less than 192 hours PVC Laboratory Grade Short term suitability. Loss of

plasticity in less than 192 hours. PVC Solvent Grade Suitable. Only small change in

dimensions observed. Red Gum Rubber Unsuitable. 100% increase in

weight and dimensions and softening.

Viton Fluoroelastomer** Suitable. No measured effect. Silicon Unsuitable. Disintegrated after

56 hours. EPDM Unsuitable. ** Dupont Dow Elastomers

4

COBALT RECOVERY Cobalt-Nickel Selectivity The results of batch shake-out tests showing the effect of pH on Co-Ni selectivity from both sulfate and chloride media are given in Tables I and 2, respectively.

TABLE 1 - SULFATE SOLUTION Solvent (v/o) : 12% CYANEX 272 extractant, 5% isodecanol in Kermac 470B diluent Aqueous (g/l) : 1.96 Co, 98.0 Ni as sulfates Temperature : 50oC Contact Time : 5 minutes A/O : 1 pH Control : NH4OH

% Extraction Equilibrium Separation Co Ni pH Factor

21.5 0.04 3.8 700 43.7 0.08 4.2 1000 88.0 0.37 5.3 2000 96.7 1.05 5.7 2700 100 1.81 6.1

TABLE 2- CHLORIDE SOLUTION Solvent (v/o) : 10% CYANEX 272 extractant, 5% isodecanol in Kermac 470B diluent Aqueous (g/l) : 0.88 Co, 1.76 Ni as chlorides Temperature : 50oC Contact Time : 5 minutes A/O : 1 pH Control : NaOH

% Extraction Equilibrium Separation Co Ni pH Factor

2.9 0.1 3.2 40 54.2 0.3 4.0 370 98.1 7.0 5.1 680 99.7 30.0 5.5 680 99.9 72.9 6.2 650

5

Calcium Rejection Unlike other organophosphorus cobalt extractants, CYANEX 272 extractant will extract cobalt preferentially to calcium when both are present in the same feed stream. This performance characteristic is demonstrated in Table 3 and Figure 1.

TABLE 3- CALCIUM REJECTION IN THE PRESENCE OF COBALT AND NICKEL

Solvent (v/o) : 15% CYANEX 272 extractant, 10% p-nonylphenol in Kermac 470B diluent Aqueous (g/1) : 1.60 Co, 77 Ni, 0.31 Ca as sulfates Temperature : 50oC Contact Time : 5 minutes A/0 : 1 pH Control : NH4OH

% Extraction Equilibrium Co Ni Ca pH

3.1 0 0.95 1.99 17.2 0.04 1.24 3.34 54.3 0.17 3.33 3.85 91.7 1.03 12.0 4.84 98.3 3.95 25.7 5.72 100 13.4 5.16 6.63

Cobalt Extraction Isotherm Procedural details and results of our extraction studies are given in Table 4.

TABLE 4 Solvent (v/o) : 12% CYANEX 272 extractant, 5% isodecanol in Kermac 470B diluent. Aqueous (g/1) : 5 Co as sulfate Temperature : 50oC Equilibrium pH : 5.00.1 pH Control : 1N NaOH

Equilibrium Cobalt Concentration (g/l) A/O Solvent Aqueous

10 6.32 4.68 5 6.13 4.13 2 5.54 2.58 1 2.72 0.06 The actual loading capacity of this solvent was 6 g/l cobalt, whereas the stoichiometric capacity is approximately 10 g/l cobalt. Cobalt Loading Loading studies were carried out at 50'C and pH 6.0 0. 1. The pH was controlled by the addition of ammonia. Other details and results are shown in Table 5.

TABLE 5 Solvent (v/o) : 30% CYANEX 272 extractant in Kermac 470B diluent Aqueous (g/l) : 10 Co as sulfate Theoretical Maximum (g/l) : Approximately 24 Contact Time : 5 minutes

Co % of Theoretical A/O in Solvent (g/l) Maximum 0.5 5 21 1.0 10 42 1.5 15 63 3.0 23* 96 5.0 23* 96

*At this loading the solvent was judged to be too viscous for practical use. The 15 g/l solvent did not exhibit this viscosity problem. The maximum practical loading for the conditions cited is probably about 65-75 % of theoretical. (39) This would correspond to a CYANEX 272 extractant:cobalt ratio of 6:2.

6

It should be noted that the loading capacity of CYANEX 272 extractant will vary depending upon several parameters, notably pH, temperature, and extractant concentration, and may be more or less than the figure cited. For example, with a 15% CYANEX 272 extractant solution at 50oC and pH 5-5 the solvent can be loaded to 100% of the theoretical maximum while remaining sufficiently mobile for practical use. Scrubbing Isotherm As can be seen from the results in Table 6, even if a high quantity of nickel is co-extracted with the cobalt, it can be successfully scrubbed from the loaded solvent.

TABLE 6 Solvent (v/o) : 12% CYANEX 272 extractant,

5% isodecanol in Kermac 470B diluent

Solvent Loading (g/1) : 1.9 Co, 1.9 Ni Scrub Feed (g/1) : 30 Co (as sulfate), initial pH 3.7 Temperature : 50oC

Equilibrium Concentration in Scrubbed Solvent (g/ml)

Co-Ni O/A Co Ni Ratio

10 3820 4.5 850 5 3790 2.2 1720 2 3740 1.3 2900 1 3730 1.1 3400 Stripping Isotherms Stripping from a solvent modified with isodecanol tended to produce hazing. Substituting p-nonylphenol or TBP for the isodecanol essentially eliminated this problem. Tables 7 and 8 show stripping isotherms obtained with a p-nonylphenol modified solvent.

TABLE 7 -USING H2SO4

Solvent (v/o) : 12% CYANEX 272 extractant, 10% p-nonylphenol in Kermac 470B diluent Solvent Loading (g/l) : 3.26 Co (2 g/ml Ni) Temperature : 40oC Contact Time : 5 minutes Strip Feed (g/1) : 20.5 Co (as sulfate), 24.5 H2SO4

Equilibrium Cobalt Conc. (g/l) O/A Organic Aqueous

6.67 0.58 38.4 5 0.22 35.7 4 0.19 32.5 3.33 0.03 31.3 2.86 0 29.8 2 0 27.0

TABLE 8 - USING HCl Solvent (v/o) : 12% CYANEX 272 extractant,

10% p-nonylphenol in Kermac 470B diluent

Solvent Loading (g/1) : 9.26 Co Temperature : 50oC Contact Time : 5 minutes Strip Feed (g/1) : 19.4 Co (as chloride) 100 HCl

Equilibrium Cobalt Conc. (g/l) O/A Organic Aqueous

2 0 37.9 3 0 47.1 5 0 65.7 7.5 0.01 88.8

10 0.35 108.5 Continuous Separation of Cobalt from Nickel in Sulfate Solution In continuous countercurrent tests (four extraction and two scrub stages) carried out at Warren Spring Laboratory (Stevenage, U.K.), more than 99.5% of the cobalt in the feed was recovered as a product containing a Co-Ni ratio of greater than 1000 to 1.

7

The experimental conditions are shown below. A circuit flowsheet and the relevant assays are given in Figure 2.

Solvent (v/o) : 20% CYANEX 272 extractant

(NH4 salt)*, 10% p-nonylphenol Aqueous Feed (g/l) : 2 Co, 100 Ni as sulfates, 20 (NH4)2O4, pH 5 Scrub Feed (g/l) : 40 Co as sulfate, pH 3 Temperature : 50oC Phase Ratios : Extraction A/O = 2 Scrubbing O/A = 32 Mixer Residence Time : 3.5-4 minutes (Based upon total

liquid flow)

*The phosphinic acid contained in the solvent was converted 70% to the ammonium salt by reaction with concentrated ammonium hydroxide solution (S.G. = 0.88). A phase modifier was used since converting more than 50% of the free acid to a salt (NH4+ or Na+) usually requires a modifier to prevent third phase formation.

** A product of Shell Chemical Co.

Effect of Process Variables on Cobalt-Nickel Separation Factor

The effect of pH, temperature and diluent aromaticity on the cobalt-nickel separation factor in sulfate solutions was measured in a series of statistically designed tests and the data fitted to the following mathematical model: log10S = 1.8827 + 0.0332T + 0.01249A + 0.0033PT - 0.002151PA - 0.0003405T2 Where: S = Co-Ni Separation Factor T = Temperature (oC) A = % Aromatics in diluent P = Equilibrium pH

8

The effect of these process variables on the separation factor is shown in Tables 9 through 11.

TABLE 9 - EFFECT OF TEMPERATURE Solvent (v/o) : 22% CYANEX 272 extractant in the diluent (95% MSB 210* diluent, 5% Aromatic 150** diluent). Aqueous (g/l) : 2 Co, 100 Ni as sulfates pH : 5.5 A/O : 1

Co-Ni Separation Temperature Factor oC 1320 30 1850 35 2480 40 3220 45 4000 50 4790 55 5510 60

* A product of Shell Chemical Co.

**A product of Exxon Co., USA.

TABLE 10 - EFFECT OF EQUILIBRIUM pH Temperature : 50oC Diluent (v/o) : 95% MSB 210, 5% Aromatic 150 Other Conditions : See Table 9

Co-Ni Separation Factor pH 2810 4.5 3010 4.7 3230 4.9 3470 5.1 3730 5.3 4000 5.5

TABLE 11 -EFFECT OF DILUENT AROMATICITY

Temperature : 50oC Diluent (v/o) : 100% MSB 210 (aliphatic) to 100% Aromatic 150 pH : 5.5 Other Conditions : See Table 9

Co-Ni Separation Aromaticity Factor v/o 3970 0 4030 10 4090 20 4160 30 4220 40 4280 50 4350 60 4420 70 4480 80 4550 90 4620 100

The effect of the phase modifiers TBP, p-nonylphenol, isodecanol and TOPO (tri-n-octylphosphine oxide) on the separation factor is shown in Table 12.

TABLE 12 -EFFECT OF PHASE MODIFIER Extractant (v/o) : 22% Modifier : 10 v/o (TBP, isodecanol, p-

nonylphenol) 10 w/o TOPO (solid) Aqueous (g/l) : 10 Co, 100 Ni as sulfates A/O : 1 Temperature : 55oC Equilibrium pH : 5.5 Contact Time : 5 minutes Diluent : MSB 210

Co-Ni Separation Modifier Factor None 6700 TBP 3400 p-Nonylphenol 1800 Isodecanol 1000 TOPO 1000

9

OTHER POTENTIAL APPLICATIONS Diluent Oxidation and Prevention Hydrocarbon diluents oxidize readily to carboxylic acids in the presence of a cobalt (Co2+) catalyst (24,90). The formation of carboxylic acids, which are active nickel extractants, can seriously reduce the cobalt-nickel selectivity obtained with CYANEX 272 extractant. However, inhibitors such as BHT can be used to prevent this oxidation. Plants following this practice have run for many years without loss of selectivity. Recovery from Ammoniacal Solutions CYANEX 272 extractant can be used to recover cobalt from ammoniacal as well as acidic solutions. The data in Table 13 show that it outperforms other organophosphorus extractants.

TABLE 13 - EXTRACTION FROM AMMONIACAL SOLUTIONS

Solvent (v/o) : 20% extractant, 5% isodecanol in Kermac 470B diluent Aqueous (g/L) : 0.97 Co3+, 0.95 Ni2+, (NH4)2O4 for a total SO42- concentration of 16 Temperature : 50oC pH Control : 11.6 with NH4OH Contact Time : 5 minutes A/0 : 1 % Extracted Co/Ni Extractant Co Ni Separation Factor CYANEX 272 91.5 15.6 58

PC-88A 91.4 22.0 18 D2EHPA 90.4 46.9 7

Although CYANEX 272 extractant is designed primarily for cobalt-nickel separations, the data in Tables 14 and 15, and Figures 3 and 4 show that it will extract a variety of metal cations and indicate its potential for other selective separations.

TABLE 14 - EXTRACTION FROM SINGLE METAL SULFATE SOLUTIONS

Solvent : 0.6 M CYANEX 272 extractant, 10 v/o p-nonylphenol in Kermac 470B diluent Aqueous : 0.015 M metal as sulfate Temperature : 50oC pH Control : NH4OH or H2SO4 as appropriate Contact Time : 5 minutes A/O : 1 Metal % Ext. Final pH Metal % Ext. Final pH

8.8 0.25 27.6 6.33 23.6 0.85 36.0 6.59

Fe3+ 61.2 1.33 Ni2+ 52.3 6.72 88.1 1.75 84.0 7.22 98.7 2.31 92.8 7.47 14.6 0.90 14.5 3.00 24.2 1.42 29.7 4.20

Zn2+ 53.3 1.88 Mg2+ 67.1 4.76 87.7 2.40 82.0 4.99 99.4 3.08 97.4 5.81 6.4 1.73 23.9 1.11 17.7 2.64 41.9 2.50

Cu2+ 21.7 2.90 Al3+ 87.5 2.92 73.9 3.56 97.2 3.14 85.7 3.84 94.8 4.08 9.2 1.78 42.3 3.40

Co2+ 19.0 3.34 Mn2+ 86.1 3.96 70.8 4.11 99.8 5.66 99.8 5.98 3.4 4.15 7.9 1.11

Ca2+ 20.4 4.53 V4+ 21.1 1.34 81.7 5.38 46.5 1.44 99.6 6.52 85.1 1.81 4.2 2.00 19.7 3.00

Cd2+ 63.1 3.51 91.0 4.00 99.5 5.00

10

TABLE 15 - EXTRACTION FROM SINGLE METAL CHLORIDE SOLUTIONS Solvent : 0.6 M CYANEX 272 extractant in Exxsol D-80 Aqueous : 0.015 M metal as chloride Temperature : 50oC pH Control : NH4OH or HCl as appropriate Contact Time : 5 minutes A/O : 1 Metal % Ext. Final pH Metal % Ext. Final pH

0.0 3.33 32.6 0.2 25.7 4.36 35.2 0.3

Ca2+ 48.9 5.00 Fe3+ 66.4 0.7 91.9 5.90 95.2 1.1 99.4 6.45 99.0 1.4 1.9 2.8 0.0 2.0 48.0 3.5 8.5 2.6

Co2+ 86.7 4.1 Cu2+ 51.9 3.1 95.9 4.4 86.2 3.5 100.0 5.5 97.6 3.9 0.0 3.6 12.6 0.9 19.3 4.9 22.6 1.2

Ni2+ 44.7 5.2 Zn2+ 54.2 1.6 84.8 5.9 67.9 1.7 95.1 6.3 76.2 1.8 99.7 7.0 92.9 2.1 1.2 3.4 41.2 4.4

Mg2+ 66.2 5.0 89.1 5.4 99.0 6.4 99.9 6.6

11

FIGURE 3 - EXTRACTION OF METALS BY CYANEX 272 EXTRACTANT FROM SULFATE SOLUTIONS

0

2 0

4 0

6 0

8 0

1 0 0

0 1 2 3 4 5 6 7 8

p H

%

E

x

t

r

a

c

t

i

o

n

V 4 +F e 3 +

M g 2 +

N i2 +

C o 2 +

C u 2 +Z n 2 + M n 2 +

C a 2 +

A l3 +

12

FIGURE 4 - EXTRACTION OF METALS BY CYANEX 272 EXTRACTANT FROM CHLORIDE SOLUTIONS

0

20

40

60

80

100

0 2 4 6 8

pH

%

E

x

t

r

a

c

t

i

o

n

Fe3+Zn2+ Cu2+

Co2+

Mg2+

Ni2+

Ca2+

13

ANALYTICAL METHODS Analysis for Active Component in CYANEX 272 Extractant in Organic Solvents by Titration The active component of CYANEX 272 extractant is bis(2,4,4-trimethylpentyl)phosphinic acid. Its concentration in an organic solvent is determined by titration with standard caustic solution.

The extractant contains small quantities of a dibasic impurity (2,4,4-trimethylpentyl phosphonic acid) which also titrates with caustic.

The endpoints are detected potentiometrically. Apparatus pH meter Magnetic stirrer Standard laboratory glassware Reagents 75 v/o 2-propanol in distilled water 0.1N Standard NaOH solution in 75 v/o 2-propanol 100 g/l H2SO4 All reagents are AR grade. Procedure 1. Contact approximately 50 ml of the solvent to be analyzed

with 50 ml of 100 g/l H2SO4 for 5 minutes at 50oC. Separate the phases and allow to stand for 15-30 minutes. Centrifuge the solvent or filter through PS paper* to remove entrained aqueous.

2. To prepare the analyte solution, pipette a 25 ml aliquot of

the solvent and dilute to 200 ml in a volumetric flask with the appropriate diluent (Escaid**, Kermac*** etc.). Alternatively, the 75 v/o solution of 2-propanol may be used for volume make-up.

3. Pipette 25 ml of the analyte solution into a 150 ad tall-form

beaker. Dilute to approximately 50 ml with the 2-propanol solution. Insert the pH electrodes and begin stirring.

* Phase separation paper available from Whatman Inc., Clifton, NJ. ** A product of Exxon Chemical Co., USA *** A product of Kerr McGee Refining Corp.

4. Note the initial pH and begin to titrate with 0.1N NaOH. Record the pH as a function of the volume of NaOH added. Three endpoints should be observed. As each endpoint is approached, the incremental addition of NaOH should be reduced to 0.1 ml to facilitate calculation of the titer by the method of second differences.

Calculation A typical potentiometric curve is as follows:

The titer T1 corresponds to the neutralization of sulfuric acid dissolved in the solvent. T2 represents the neutralization of the phosphinic acid plus the reaction of the first of two replaceable hydrogen ions associated with the phosphonic acid. The phosphonic acid is totally neutralized at T3. 0.1N NaOH First Second

(ml) pH Differential Differential 9.8 7.50 50 9.9 8.00 +40 90 10.0 8.90 +90 180 10.1 10.70 -130 50 10.2 11.20 -40 10 10.3 11.30 Then, T2 = (10.0 + 0.1) x 90 = 10.04 ml 90 + 130

R2POH + NaOH R2PONa + H2O

O O

RP(OH)2 + 2NaOH RP(ONa)2

O O

14

T1 and T3 may be calculated in an analogous manner. When all three titers are known, the concentration of bis(2,4,4-trimethylpentyl)phosphinic acid may be determined. bis(2,4,4-trimethylpentyl) phosphinic acid (g/1) = [T2 (T3 T2) T1] x N(NaOH) x 290 x 1000 1000 x 25 x 25 200 Similarly the concentration of the phosphonic acid and dissolved sulfuric acid may also be calculated. 2,4,4-trimethylpentyl phosphonic acid (g/1) = T2 T2 x N(NaOH) x 194 x 1000 1000 x 25 x 25 200 H2SO4 (g/l) = T1 x 49 x N(NaOH) x 1000 1000 x 25 x 25 200 NOTES 1. A minimum net titer, i.e. [T2 (T3 T2) T1], of 10 ml is

recommended to obtain reproducible results. In this procedure, 10 ml of 01N NaOH is equivalent to approximately 100 g/l concentration of phosphinic acid. Where necessary, the size of the aliquots and dilutions may be varied to ensure a sufficient volume of titrant is consumed.

2. Approximate pH's corresponding to the T1, T2 and T3

endpoints are 4, 9 and 11, respectively. However these values may vary depending upon the composition of the solvent. After gaining experience with a system, the NaOH may be added rapidly until the particular endpoint pH is approached and then added in 0.1 ml increments to define the point of inflexion in the curve.

3. The concentrations of sulfuric and phosphonic acids in the

solvent are usually small and these endpoints may not be observed. In this case T1 and T3 should be assigned a value of zero in the calculations. Typically, T1 and T3 - T2) will be < 0.2 and < 0.1 ml of 0.1N NaOH, respectively, corresponding to

15

Detector Parameters: Type: Flame Ionization Detector (FID) Temperature: 300oC Helium Flow: 8 mL/min Hydrogen Flow: 35 mL/min Air Flow: 400 mL/min Makeup Flow: 35 mL/min Makeup Gas Type: Helium Sample Injection: Volume: 0.1 L Peak Areas: Electronic integration. The

compound has a retention time of about 17.8 minutes.

Analysis for Active Component in CYANEX 272 Extractant in Aqueous Solutions by Gas Chromatography The concentration of the active component, bis(2,4,4-trimethylpentyl)phosphinic acid in water is determined by gas chromatography of its methylated derivative. Procedure 1. Transfer approximately 1 L of the aqueous solution into a plastic container and place it in a water bath set for 45oC for a few hours. 2. Remove the solution from the water bath and allow to cool to room temperature. 3. From the bottom of the plastic container, dispense 600 g of the solution into a 1 L separatory funnel. 4. Add to the solution 5 mL of concentrated sulphuric acid, 50 mL of toluene and approximately 100 g of sodium chloride. 5. Separate both aqueous and organic phases. 6. Pipette a 1000 L aliquot of the organic phase and transfer it into a HP autosampler vial. Add 200 L of Methyl-8 Concentrate. 7. Prepare standard solutions of CYANEX 272 extractant in toluene. 8. Pipette a 1000 L aliquot of the standard solutions and transfer it into a HP autosampler vial. Add 200 L of Methyl-8 Concentrate. 9. Analyze the methylated sample and standard solutions by gas chromatography. The chromatographic conditions are identical to those previously described in the section Analysis for Active Component in CYANEX 272 Extractant in Organic Solvents by Gas Chromatography, except the volume injected by the GC autosampler is 1.0 L.

16

TECHNICAL PAPERS AND PATENTS Technical Papers (listed chronologically) 1. Solvent extraction of cobalt and nickel by organophosphorus

acids I. Comparison of phosphoric, phosphonic and phosphinic acid systems Preston, J.S. Hydrometallurgy, 9, Pages 115-133 (1982)

2. Cobalt-nickel separation by solvent extraction with a

dialkylphosphinic acid Rickelton, W.A., Flett, D.S. and West, D.W. Proc. Int. Solvent Extr. Conf., Pages 195-196 (1983)

3. Recent developments in the separation of nickel and cobalt

from sulphate solutions by solvent extraction Preston, J.S. J.S. Afr. Inst. Min. Metall., 83(6), Pages 126-132 (1983) 4. Vanadium-uranium extraction from Wyoming vanadiferous

silicates Hayashi, M., Nichols, I.L. and Huiatt, J.L. Rep. Invest. - U.S., Bur. Mines, RI 8822, 9 pp. (1983) 5. Cobalt-nickel separation by solvent extraction with bis(2,4,4-

trimethylpentyl)phosphinic acid Rickelton, W.A., Flett, D.S. and West, D.W. Solvent Ext. Ion Exch., 2(6), Pages 815-838 (1984) 6. Extraction equilibria of ammonia with acidic

organophosphorus extractants Inoue, K., Nakayama, D. and Watanabe, Y. Proc. Symp. Solvent Extr., Pages 127-132 (1984) 7. Separation of cobalt and nickel by liquid-liquid extraction

and supported liquid membranes with di(2,4,4-trimethylpentyl)phosphinic acid [CYANEX 272]

Danesi, P.R., Reichley-Yinger, L., Cianetti, C. and Rickert, P.G. Solvent Extr. Ion Exch., 2(6), Pages 781-814 (1984) 8. Cobalt recovery from copper leach solutions Jeffers, T.H. and Harvey, M.R. Rep. Invest. - U.S., Bur. Mines, RI 8927, 12 pp. (1985) 9. Determination of the equilibrium constants of

organophosphorus liquid-liquid extractants by inductively coupled plasma-atomic emission spectroscopy

Li, K., Muralidharan, S. and Freiser, H. Solvent Extr. Ion Exch., 3(6), Pages 895-908 (1985) 10. Glycine enhanced separation of Co(II) and Ni(II) with

bis(2,4,4-trimethylpentyl)phosphinic acid [CYANEX 272] by liquid-liquid extraction and supported liquid membranes

Reichley-Yinger, L. and Danesi, P.R. Solvent Extr. Ion Exch., 3(1&2), Pages 49-60 (1985)

11. Selectivity-structure trends in the extraction of Co(II) and

Ni(II) by dialkyl phosphoric, alkyl alkylphosphonic, and dialkylphosphinic acids

Danesi, P.R., Reichley-Yinger, L., Mason, G., Kaplan, L., Horwitz, E.P. and Diamond, H.

Solvent Extr. Ion Exch., 3(4), Pages 435-452 (1985) 12. Separation and recovery of cobalt from copper leach

solutions Jeffers, T.H. J. Met., 37(1), Pages 47-50 (1985) 13. Studies on organophosphorus compounds Oxidative

phosphinylation A new route to dialkylphosphinic acid derivatives

Yuan, C., Long, H., Shen, D. and Chen, W. Scientia Sinica (Series B), XXVIII(4), Pages 359-364 (1985) 14. A composite supported liquid membrane for ultraclean Co-

Ni separations Danesi, P.R. and Reichley-Yinger, L. J. Membr. Sci., 27(3), Pages 339-347 (1986)

15. A possible use of photo-reaction in liquid-liquid extraction of

substitution-inert metal complexes. Extraction of chromium(III) and cobalt(III) complexes

Ohki, A., Fujino, Y., Ohmori, K. and Takagi, M. Solvent Extr. Ion Exchange, 4(4), Pages 639-662 (1986) 16. Extraction and separation of metals with Levextrel resins

Baba, Y., Inoue, K., Yoshizuka, K., Sakamoto, Y. and Nakashima, H. Proc. Symp. Solvent Extr., Pages 79-84 (1986)

17. Extraction and stripping of iron(III) in systems of sulfuric

acid and monoacidic phosphates and phosphonates Yu, S. and Wu, Z. Youse Jinshu, 38(3), Pages 39-45 (1986) 18. Extraction equilibria of ammonia with acidic

organophosphorus compounds Inoue, K., Nakayama, D. and Watanabe, Y. Hydrometallurgy, 16(1), Pages 41-53 (1986) 19. Extraction equilibria of indium(III) from nitric acid with

acidic organophosphorus compounds Inoue, K., Baba, Y., Yoshizuka, K., Soejima, K. and Nakamura, H. Proc. Symp. Solvent Extr., Pages 181-184 (1986)

20. Extraction of lanthanide metals with bis(2,4,4-

trimethylpentyl)phosphinic acid Li, K. and Freiser, H. Solvent Extr. Ion Exch., 4(4), Pages 739-755 (1986)

17

21. Solvent extraction equilibria of neodymium and

praseodymium with acidic organophosphorus compounds Inoue, K., Fujino, O. and Arita, H. Nippon Kogyo Kaishi, 102(1182), Pages 491-494 (1986) 22. Some experiences in the separation of Co-Ni with PC 88A

and CYANEX 272 in mixed sulphate-chloride media Szilassy, I., Mikta, G. and Vadasdi, K. Proc. Int. Solvent Extr. Conf., 2, Pages 519-525 (1986) 23. Some observations on the performance of hollow-fiber

supported liquid membranes for Co-Ni separations Danesi, P.R. and Rickert, P.G. Solvent Extr. Ion Exch., 4(1), Pages 149-164 (1986) 24. The cobalt catalysed oxidation of solvent extraction diluents Flett, D.S. and West, D.W. Proc. Int. Solvent Extr. Conf., 2, Pages 3-10 (1986) 25. The kinetics of cobalt and nickel extraction using HEHEHP Dreisinger, D.B. and Cooper, W.C. Solvent Extr. Ion Exch., 4(2), Pages 317-344 (1986) 26. The recovery of nickel from chloride leach liquors with alkyl

phosphoric acid/aliphatic oxime mixtures Rice, N.M. and Smith, D.C. Proc. Int. Solvent Extr. Conf., 2, Pages 633-641 (1986) 27. Adsorption of nickel(II) and cobalt(II) from aqueous

solutions on Levextrel resin containing acidic organophosphinic extractant and phosphorus-based chelating resins: comparative study on the selectivity of the resins

Inoue, K., Baba, Y., Sakamoto, Y. and Egawa, H. Sep. Sci. Technol., 22(4), Pages 1349-1357 (1987) 28. Applications of solvent extraction in treatment of metal

finishing wastes Brooks, C.S. Met. Finish., 85(3), Pages 55-60 (1987) 29. Chemistry of nickel-cobalt separation

Flett, D.S. Extractive Metallurgy of Nickel, Eds, Burkin, A.R., Pages 76-97 (1987)

30. Extraction of cobalt. XI. Relation between structure of

organophosphorus acids and their properties in extraction separation of cobalt from nickel

Li, J., Zhu, T. and Chen, J. Wuji Huaxue, 3(3), Pages 7-15 (1987) 31. Extraction of molybdenum oxyl cation by monoacidic

phosphates and phosphonates Yu, S. Youkuangye, 6(2), Pages 27-33 (1987)

32. Investigation on the potential techniques to recover gold

from thiourea solution Deschnes, G. Proc. Int. Symp. Gold Metall., Pages 359-377 (1987)

33. Measurement of self-diffusion coefficients in extractant

systems using the FT-NMR technique Wrnheim, T. and Paatero, E.Y.O. Hydrometallurgy, 19(1), Pages 129-134 (1987)

34. Modern extractants for copper, cobalt and nickel Cox, M. and Flett, D.S. Chem. Ind., Pages 188-193 (1987) 35. Recovery of cobalt and copper from complex sulfide

concentrates Dannenberg, R.O., Gardner, P.C., Crane, S.R. and Seidel, D.C. Rep. Invest. - U.S., Bur. Mines, RI 9138, 20 pp. (1987)

36. Recovery of cobalt from spent copper leach solution using

continuous ion exchange Jeffers, T.H., Gritton, K.S., Bennett, P.G. and Seidel, D.C. Rep. Invest. - U.S., Bur. Mines, RI 9084, 17 pp. (1987)

37. Small-angle neutron-scattering studies of cobalt(II)

organophosphorus polymers in deuteriobenzene Thiyagarajan, P., Diamond, H., Danesi, P.R. and Horwitz, E.P. Inorg. Chem., 26, Pages 4209-4212 (1987) 38. Solvent extraction in hydrometallurgy Flett, D.S. Proc. 3rd Int. Symp. Hydrometallurgy, Pages 39-64 (1987) 39. Solvent extraction of cobalt and nickel in bis(2,4,4-

trimethylpentyl) phosphinic acid, "CYANEX -272" Fu, X. and Golding, J.A. Solvent Extr. Ion Exch., 5(2), Pages 205-226 (1987) 40. Solvent extraction of zirconium(IV) by organophosphorus

compounds Sella, C. and Bauer, D. Separation Processes in Hydrometallurgy, Eds, Davies, G.A.,

Pages 207-214 (1987) 41. A quantitative structure-reactivity study of mono-basic

organophosphorus acids in cobalt and nickel extraction Yuan, C., Xu, Q., Yuan, S., Long, H., Shen, D., Jiang, Y., Feng,

H., Wu, F. and Chen, W. Solvent Extr. Ion Exch., 6(3), Pages 393-416 (1988) 42. Commercial applications of phosphorus-based solvent

extractions Johnston, B.E. Chem. Ind., Pages 656-660 (1988) 43. Diphasic acido-basic properties of organophosphorus acids Sella, C. and Bauer, D. Solvent Extr. Ion Exch., 6(5), Pages 819-833 (1988) 44. Equilibria in the solvent extraction of indium(III) from

nitric acid with acidic organophosphorus compounds Inoue, K., Baba, Y. and Yoshizuka, K. Hydrometallury, 19(3), Pages 393-399 (1988)

18

45. Equilibrium and mass transfer for the extraction of cobalt

and nickel from sulfate solutions into bis(2,4,4-trimethylpentyl)phosphinic acid - "CYANEX 272" Fu, X. and Golding, J.A. Solvent Extr. Ion Exch., 6(5), Pages 889-917 (1988)

46. Extraction of uranium(VI) from hydrochloric acid solutions

by dialkyl phosphinic acid Sato, T. and Sato, K. Proc.Symp. Solvent Extr., Pages 61-66 (1988)

47. Formation of microemulsion in solvent extraction systems

containing CYANEX 272 Paatero, E., Ernola, P., Sjblom, J. and Hummelstedt, L. Proc. Int. Solvent Extr. Conf., 2, Pages 124-127 (1988)

48. Kinetics of Co(II) extraction with bis(2,4,4-

trimethylpentyl)phosphinic acid Hummelstedt, L., Westerholm, K. and Alitalo, J. Proc. Int. Solvent Extr. Conf., 2, Pages 65-68 (1988) 49. Molecular modeling of organic extractants

Gatrone, R.C. and Horwitz, E.P. Solvent Extr. Ion Exch., 6(6), Pages 937-972 (1988)

50. On the extraction of cobalt(II), nickel(II) and iron(III) from

acidic leach liquors Maljkovi, D., Lenhard, Z. and Balen, M. Proc. Int. Solvent Extr. Conf., 4, Pages 269-271 (1988) 51. Recovery of cobalt from spent copper leach solution

Improved elution and impurity removal techniques with revised process economics

Bennett, P.G. and Jeffers, T.H. Rep. Invest. U.S. Bur. Mines, RI 9190, 9 pp (1988) 52. Recovery of cobalt from spent copper leach solution using

continuous ion exchange Jeffers, T.H., Gritton, K.S., Bennett, P.G. and Seidel, D.C. Nucl. Chem. Waste Manag., 8, Pages 37-44 (1988) 53. Separation of Ga, In, and Zn by supported liquid

membranes Yonehara, T., Yamamoto, A., Matsuyama, H. and Teramoto, M. Proc. Symp. Solvent Extr. Pages 151-156 (1988)

54. Solvent extraction equilibria of gallium(III) with acidic organophosphorus compounds from aqueous nitrate media

Inoue, K., Baba, Y. and Yoshizuka, K. Solvent Extr. Ion Exch., 6(3), Pages 381-392 (1988) 55. Solvent extraction of gallium and indium with acidic

extractants Inoue, K., Baba, Y. and Yoshizuka, K. Proc. Symp. Solvent Extr., Japan, Pages 31-36 (1988)

56. Solvent extraction of tervalent lanthanides as chelates. A

systematic investigation of extraction equilibria Freiser, H. Solvent Extr. Ion Exch., 6(6), Pages 1093-1108 (1988)

57. Solvent extraction with organophosphines Commercial &

potential applications - Rickelton, W.A. and Boyle, R.J. Sep. Sc. Technol., 23(12&13), Pages 1227-1250 (1988) 58. Some investigations on the solvent extraction of

chromium(VI) by bis(2,4,4-trimethylpentyl)phosphinic acid (CYANEX - 272) Rao, V.M. and Prasad, S.K. Proc. Int. Solvent Extr. Conf., 1, Pages 338-340 (1988)

59. Determination of some basic constants for bis(2,4,4-

trimethylpentyl)phosphinic acid - CYANEX 272 Fu, X., Hu, Z., Liu, Y. and Golding, J.A. Proc. Int. Conf. Sep. Sci. Technol., 1, Pages 214-221 (1989)

60. Equilibrium and kinetic studies for the extraction of nickel

from sulphate solutions into CYANEX 272 Fu, X., Zhao, S., Hu, Z., Sui, S., Hao, J. and Golding, J.A. Proc. Int. Conf. Sep. Sci. Technol., 1, Pages 205-213 (1989)

61. Extraction equilibrium of molybdenum(VI) with CYANEX

272 Cao, Y. and Nakashio, F. Mo Kexue Yu Jishu, 9(4), Pages 6-12 (1989) 62. Extraction mechanism of rare earth metals in the presence

of diethylenetriaminepentaacetic acid in aqueous phase Matsuyama, H., Okamoto, T., Miyake, Y. and Teramoto, M. J. Chem. Eng. Jpn., 22(6), Pages 627-635 (1989)

63. Extraction of tungsten and molybdenum by various organic

compounds as extractants Yuan, Q., Cheng, X., Luo, J. and Yuan, C. Rare Met., 8(3), Pages 15-19 (1989) 64. Extraction separation of tervalent lanthanide metals with

bis(2,4,4-trimethylpentyl)phosphinic acid Komatsu, Y. and Freiser, H. Anal. Chim. Acta, 227(2), Pages 397-404 (1989) 65. Metal complexes with phosphonic and phosphinic acids Aguilar, M., Miralles, N. and Sastre, A.M. Rev. Inorg. Chem., 10(1-3), Pages 93-119 (1989) 66. Purification of CYANEX 272 extractant

Yang, Y., Shen, J. and Sun, S. Huaxue Shiji, 11(6), Page 381 (1989)

67. Solvent extraction of indium(III) and gallium(III) with

various acidic extractants Inoue, K. Shigen to Sozai, 105(10), Pages 751-754 (1989)

68. Synergistic extraction of ferric iron in sulfate solutions by

tertiary amine and 2-ethylhexyl 2-ethylhexylphosphonic acid (HEHEHP) or dialkylphosphinic acid Yu, S. and Chen, J. Hydrometallurgy, 22(1/2), Pages 183-192 (1989)

19

69. Analytical utility of coupled transport across a supported

liquid membrane. Selective preconcentration of zinc Cox, J.A. and Bhatnagar, A. Talanta, 37(11), Pages 1037-1041 (1990) 70. Application of supported liquid membranes for removal of

uranium from groundwater Chiarizia, R., Horwitz, E.P., Rickert, P.G. and Hodgson, K.M. Sep. Sci. Technol., 25(13-15), Pages 1571-1586 (1990) 71. Distribution equilibria in the adsorption of cobalt(II) and

nickel(II) on Levextrel resin containing CYANEX 272 Yoshizuka, K., Sakomoto, Y., Baba, Y. and Inoue, K. Hydrometallurgy, 23(2/3), Pages 309-318 (1990) 72. Extraction of divalent metals with bis(2,4,4-

trimethylpentyl)phosphinic acid Sastre, A.M., Miralles, N. and Figuerola, E. Solvent Extr. Ion Exch., 8(4&5), Pages 597-614 (1990) 73. Extraction of sodium in bis(2,4,4-trimethylpentyl)phosphinic

acid "CYANEX 272": basic constants and extraction equilibria

Fu, X., Hu, Z., Liu, Y. and Golding, J.A. Solvent Extr. Ion Exch., 8(4&5), Pages 573-595 (1990) 74. Immobilized extractants: selective transport of magnesium

and calcium from a mixed chloride solution via a hollow fiber module

Belfer, S., Binman, S., Lati, Y. and Zolotov, S. J. Appl. Polym. Sci., 40(11-12), Pages 2073-2085 (1990) 75. Improved separation of closely related metal ions by

centrifugal partition chromatography Muralidharan, S., Cai, R. and Freiser, H. J. Liq. Chromatogr., 13(18), Pages 3651-3672 (1990) 76. Mechanism of membrane extraction of Molybdenum(VI)

with CYANEX 272 Cao, Y. and Nakashio, F. Huaxue Fanying Gongcheng Yu Gongyi, 6(3), Pages 67-73

(1990) 77. Phase behaviour in metal extraction systems Paatero, E. and Sjblom, J. Hydrometallurgy, 25(2), Pages 231-256 (1990) 78. Study of uranium removal from groundwater by supported

liquid membranes Chiarizia, R. and Horwitz, E.P. Solvent Extr. Ion Exch., 8(1), Pages 65-98 (1990) 79. The effect of trioctylphosphine oxide on phase and

extraction equilibria in systems containing bis(2,4,4-trimethylpentyl)phosphinic acid

Paatero, E, Lantto, T. and Ernola, P. Solvent Extr. Ion Exch., 8(3), Pages 371-388 (1990) 80. The selective recovery of zinc with new thiophosphinic acids Rickelton, W.A. and Boyle, R.J. Solvent Extr. Ion Exch., 8(6), Pages 783-797 (1990)

81. An improved extractant for separation of ammonia from

sour waters by combined stripping and extraction Poole, L.J. and King, C.J. Solvent Extr. Ion Exch., 9(1), Pages 103-125 (1991) 82. Extraction of Co(II) and Ni(II) with CYANEX 272 Maljkovi, D., Lenhard, Z. and Balen, M. EMC91: Non-Ferrous Metallurgy Present and Future, Pages

175-181 (1991) 83. Extraction of Sc3+ and Fe3+ from hydrochloric acid medium

with bis(2,4,4-trimethylpentyl)phosphinic acid Ma, G. and Li, D. Proc. 2nd Chin. Sov. Semin. Chem. Applic. Rare Earths, Pages

50-53 (1991) 84. Kinetics and mechanism of yttrium extraction with three

acidic phosphorus extractants Ma, E., Jiang, P. and Jin, P. J. Chem. Technol. Biotechnol., 51, Pages 315-321 (1991)

85. Modification of hollow fibers by impregnation and radiation Belfer, S. and Binman, S. Proc. Int. Conf. Ion Exch., Pages 441-446 (1991) 86. Organophosphorus compounds in extraction of metal ions Gega, J. and Walkowiak, W. Rudy Metale, 36(1), Pages 27-32 (1991) 87. Separation of thulium, ytterbium and lutetium by

centrifugal partition chromatography with organophosphinic acid

Suzuki, Y., Nakamura, S. and Akiba, K. Anal. Sci., 7, Pages 249-252 (1991) 88. Solvent extraction of thorium, uranium and some metals

from nitrate solution with organophosphinic acid Akiba, K., Olivos, R.C. and Nakamura, S. Proc. Symp. Solvent Extr., Japan, Pages 181-186 (1991) 89. The potential for recovery of cobalt from copper leach

solutions Sole, K.C. and Hiskey, J.B. Proc. of the Copper 91-Cobre 91 Int. Symp., Hydrometallurgy

and Electrometallurgy of Copper, Canada, 3, Pages 229-243 (1991)

90. The significance of diluent oxidation in cobalt-nickel

separation Rickelton, W.A., Robertson, A.J. and Hillhouse, J.H. Solvent Extr. Ion Exch., 9(1), Pages 73-84 (1991) 91. The solvent extraction of europium(II) by some

organophosphorus and carboxylic acids Preston, J.S. and du Preez, A.C. Solvent Extr. Ion Exch., 9(2), Pages 237-257 (1991) 92. Transport of lanthanoid elements through liquid membrane

with organophosphinic acid Nakamura, S., Takeyasu, M. and Akiba, K. Proc. Symp. Solvent Extr., Japan, Pages 45-52 (1991)

20

93. Application of new hydrometallurgical developments in the

Outokumpu HIKO process Nyman, B., Aaltonen, A., Hultholm, S.E. and Karpale, K. Hydrometallurgy, 29, Pages 461-478 (1992) 94. Comparison of aggregates formed by acidic

organophosphorus extractants and metals (Ni and Co) in solvent extraction

Zhou, N.F., Wu, J., Sarathy, P.K., Liu, F. and Neuman, R.D. Solvent Extraction, Eds, Sekine, T., Pages 165-170 (1992) 95. Extraction rates of Tb, Tm and Lu with acidic

organophosphorus reagents Nakamura, S., Yamada, K. and Akiba, K. Proc. Symp. Solvent Extr., Japan, Pages 169-174 (1992) 96. Extraction separation of scandium(III) and iron(III) from

hydrochloric acid solutions with bis(2,4,4-trimethylpentyl)phosphinic acid

Ma, G. and Li, D. Fenxi Huaxue, 20(10), Pages 1113-1116 (1992) 97. Extractive separation of copper(II) and zinc(II) using

emulsion liquid membrane Cao, Y., Goto, M. and Nakashio, F. Mo Kexue Yu Jishu, 12(4), Pages 12-16 (1992)

98. Novel uses for thiophosphinic acids in solvent extraction Rickelton, W.A. J. Metals, 44(5), Pages 52-54 (1992). 99. Separation of Co(II)-Zn(II), Co(II)-Mn(II) and Zn(II)-

Mn(II) systems from their binary solutions through supported liquid membrane containing organophosphorus acid as extractant

Mohapatra, R., Kanungo, S.B. and Sarma, P.V.R.B. Indian J. Chem., 31A, Pages 389-390 (1992) 100. Solvent extraction characteristics of thiosubstituted

organophosphinic acid extractants Sole, K.C. and Hiskey, J.B. Hydrometallurgy, 30(1-3), Pages 345-365 (1992) 101. Solvent extraction in hydrometallurgy Cox, M. Principles and Practices of Solvent Extraction, Eds, Rydberg, J.,

Musikas, C. and Choppin, G.R., Pages 357-412 (1992) 102. Solvent extraction of iron (III) by bis(2,4,4-trimethylpentyl)

phosphinic acid: experimental equilibrium study Miralles, N., Sastre, A.M., Figuerola, E. and Martinez, M. Hydrometallurgy, 31(1-2), Pages 1-12 (1992) 103. Solvent impregnated resins containing CYANEX 272.

Preparation and application to the extraction and separation of divalent metals

Cortina, J.L., Miralles, N., Sastre, A., Aguilar, M., Profumo, A. and Pesavento, M.

React. Polym., 18(1), Pages 67-75 (1992)

104. The recovery of cobalt and nickel from acidic sulphate

solutions in the presence of aluminum Orive, M.M., Olazabal, M.A., Fernndez, L.A. and Madariaga,

J.M. Solvent Extr. Ion Exch., 10(5), Pages 787-797 (1992) 105. W/O microemulsions formed by acidic extractants and effect

of lanthanides Wu, J., Liu, F., Yu, Z.J., Zhou, N.F. and Neuman, R.D. Solvent Extraction, Eds, Sekine, T., Pages 195-200 (1992) 106. A spectrophotometric method for the determination of

cobalt(II) in organic phases Azimi, A. and Rice, N.M. Hydrometallurgy, 32(2), Pages 223-232 (1993)

107. Bioextraction of cobalt from cobaltite Torma, A.E., Wey, J.E. and Pesic, B. Metallwissenschaft und Technik, 47(7), Pages 648-651 (1993) 108. Cobalt-nickel separation: the extraction of cobalt(II) and

nickel(II) by CYANEX 301, CYANEX 302 and CYANEX 272 Tait, B.K. Hydrometallurgy, 32(3), Pages 365-372 (1993)

109. Comparative study on kinetic behavior of solvent extraction

of Co2+ and Ni2+ with organophosphorus extractants Zhu, T. Huagong Xuebao, 44(3), Pages 343-349 (1993)

110. Comparison of extractants in the separation of samarium

and gadolinium Benedetto, J.S., Ciminelli, V.S.T. and Neto, J.D. Miner. Eng., 6(6), Pages 597-605 (1993) 111. Countercurrent tests on CYANEX 302 and CYANEX 272 as

separation reagents for cobalt-nickel Tait, B.K. Solvent Extraction in the Process Industries, Proc. of ISEC93,

3, Pages 1303-1310 (1993) 112. Dissociation constants of organophosphinic acid compounds

Martinez, M., Miralles, N., Sastre, A. and Bosch, E. Talanta, 40(9), Pages 1339-1343 (1993)

113. Extraction of metal (Ti, V, Mo)-oxyl cations by monoacidic

phosphates and phosphonates Fu, X., Fu, Y., Niu, Z., Hu, Z., Xin, H. and Zhang, Y. Rare Met., 12(2), Pages 142-147 (1993)

114. Extraction of nickel from aqueous sulfate solution into

bis(2,4,4-trimethylpentyl)phosphinic acid, CYANEX 272TM - Equilibrium and kinetic studies

Golding, J.A., Fu, X., Zhao, S., Hu, Z., Sui, S. and Hao, J. Solvent Extr. Ion Exch., 11(1), Pages 91-118 (1993) 115. Extraction of rare earth ions with bis(2,4,4-

trimethylpentyl)phosphinic acid Zhang, X. and Li, D. Yingyong Huaxue, 10(4), Pages 72-74 (1993)

21

116. Extraction of thorium(IV) by CYANEX reagents, PC-88A

and their mixtures from aqueous hydrochloric acid media Rout,.K.C., Mishra, P.K., Chakravortty, V. and Dash, K.C. Radiochim. Acta, 62(4), Pages 203-206 (1993)

117. Recovery of Mo, V, Ni and Co from spent

hydrodesulpHurization catalysts Inoue, K., Zhang, P. and Tsuyama, H. Symposium on Regeneration, Reactivation and Reworking of Spent Catalysts, Denver, 38(1), Pages 77-80 (1993)

118. Recovery of nickel and cobalt from spent

hydrodesulfurization catalysts Inoue, K. and Zhang, P. Proc. Int. Conf. Min. Metall. Complex Nickel Ores, Pages 274-

279 (1993) 119. Simultaneous characterization of extraction equilibria and

back-extraction kinetics: use of Arsenazo III to characterize lanthanide - bis(2,4,4-trimethylpentyl)phosphinic acid complexes in surfactant micelles

Inaba, K., Muralidharan, S. and Freiser, H. Anal. Chem., 65(11), Pages 1510-1516 (1993) 120. Solvent extraction of lanthanides by acidic

organophosphorus compounds Akiba, K., Yamada, K. and Nakamura, S. Nippon Kagaku Kaishi, 5, Pages 555-560 (1993)

121. Solvent extraction separation of cobalt(II) from nickel and

other metals with CYANEX 272 Gandhi, M.N., Deorkar, N.V. and Khopkar, S.M. Talanta, 40(10), Pages 1535-1539 (1993)

122. Solvent impregnated resins containing di-(2,4,4-

trimethylpentyl)phosphinic acid. I. Comparative study of di-(2,4,4-trimethylpentyl)phosphinic acid adsorbed into Amberlite XAD-2 and dissolved in toluene Cortina, J.L., Miralles, N., Sastre, A., Aguilar, M., Profumo, A. and Pesavento, M. React. Polym., 21(1-2), Pages 89-101 (1993)

123. Solvent impregnated resins containing di-(2,4,4-

trimethylpentyl)phosphinic acid II. Study of the distribution equilibria of Zn(II), Cu(II) and Cd(II) Cortina, J.L., Miralles, N., Sastre, A.M., Aguilar, M., Profumo, A. and Pesavento, M. React. Polym., 21(1-2), Pages 103-116 (1993)

124. Study on rare earth complexes with bis(2,4,4-

trimethylpentyl)phosphinic acid Li, Q., Li, D., Liu, S., Zeng, G. and Pang, L. JinshuXuebao, 29(4), Pages 13251-13257 (1993)

125. Synergistic extraction of iron(III) from sulphuric acid

solutions with mixed Kelex 100 - alkyl phosphorus acid extractants

Demopoulos, G.P., Mihaylov, I.O. and Pouskouleli, G. Solvent Extr. Ion Exch., 11(1), Pages 67-89 (1993)

126. The purification of nickel sulphate using di-(2-

ethylhexyl)phosphoric acid Clark, P.D.A., Cole, P.M. and Fox, M.H. Proc. Int. Solvent Extr. Conf., 1, 175-182 (1993) 127. Thermodynamic function of microemulsions in sodium salt

of dialkylphosphoric acid extractant systems Fu, X., Xin, H., Hu, Z. and Liu, Z. Huaxue Xuebao, 51(12), Pages 1151-1156 (1993)

128. Vibrational spectra of rare earth complexes of bis(2,4,4-

trimethylpentyl)phosphinic acid Li, Q., Zeng, G. and Li, D. Guangpuxue Yu Guangpu Fenxi, 13(6), Pages 19-24 (1993)

129. Application of europium(III) extraction with

organophosphinic acid to liquid membrane transport Nakamura, S., Sato, A. and Akiba, K. J. Radioanal. Nucl. Chem., 178(1), Pages 63-71 (1994)

130. Distributions of 14 elements from solutions simulating

Hanford high-level wastes (acid-dissolved sludge and acidified supernate) into 10 liquid extractants Marsh, S.F., Svitra, Z.V. and Bowen, S.M. Technol. Programs Radioact. Waste Manage. Environ. Restor., 1, Pages 725-731 ( 1994)

131. Effect of kinetic factors on the efficiencies of centrifugal

partition chromatographic separations of tervalent lanthanides with bis(2,4,4-trimethylpentyl)phosphinic acid as extractant Inaba, K., Freiser, H. and Muralidharan, S. Solvent Extr. Res. Dev., Jpn., 1, Pages 13-29 (1994)

132. Equilibrium and non-equilibrium separations of rare earth

metals by solvent extraction in the presence of DTPA Matsuyama, H., Azis, A., Fujita, M. and Teramoto, M. Proc. Symp. Solvent Extr., Pages 99-100 (1994)

133. Extraction mechanism of Sc(lIl) and separation from

Th(IV), Fe(Ill), and Lu(III) with bis(2,4,4-trimethylpentyl)phosphinic acid in n-hexane from sulphuric acid solutions

Wang, C. and Li, D. Solvent Extr. Ion Exch., 12(3), Pages 615-631 (1994) 134. Extractive spectrophotometric determination of cobalt using

CYANEX 272 Reddy, B.R. and Sarma, P.V.R.B. Talanta, 41(8), Pages 1335-1339 (1994) 135. Kinetics of the extraction of cobalt(II) using CYANEX 272

(di(2,4,4-trimethylpentyl)phosphinic acid) Liu, P., Wang, Y., Sun, S., Shen, J. and Yu, X. Shandong Daxue Xuebao, 29(3), Pages 320-325 (1994) 136. Liquid membrane transport of lanthanoid elements using

organophosphinic acid Nakamura, S., Takeyasu, M. and Akiba, K. J. Radioanal. Nucl. Chem., 181(2), Pages 281-289 (1994)

22

137. Metals recovery from hydrodesulphurization catalysts Delmas, F, Nogueira, C., Dalrymple, I. and Parkes, J. Int. Symp. Hydrometallurgy'94, Pages 1075-1086 (1994) 138. Organophosphinic, phosphonic acids and their binary

mixtures as extractants for molybdenum(VI) and uranium(VI) from aqueous HCl media

Behera, P., Mishra, S., Mohanty, I. and Chakravortty, V. J. Radioanal. Nucl. Chem., 178(1), Pages 179-192 (1994) 139. Purification of nickel sulphate solutions containing iron,

copper, cobalt, zinc and manganese Senapati, D., Chaudhury, G.R. and Sarma, P.V.R.B. J. Chem. Technol. Biotechnol., 59(4), Pages 335-339 (1994) 140. Separation of Zn, Co and Ni using solvent extraction

techniques Cho, E.H. and Dai, P.K.

Miner. and Metall. Process., 296, Pages 185-187 (1994) 141. Sodium salts of D2EHPA, PC-88A and CYANEX-272 and

their mixtures as extractants for cobalt(II) Devi, N.B., Nathsarma, K.C. and Chakravortty, V. Hydrometallurgy, 34(3), Pages 331-342 (1994) 142. Sodium salts of D2EHPA, PC-88A and CYANEX 272 and

their mixtures as extractants for nickel(II) Devi, N.B., Nathsarma, K.C. and Chakravortty, V. Scand. J. Metall., 23(5&6), Pages 194-200 (1994) 143. Solvent extraction of silver by CYANEX 272, CYANEX 302

and CYANEX 301 Sole, K.C., Ferguson, T.L. and Hiskey, J.B. Solvent Extr. Ion Exch., 12(5), Pages 1033-1050 (1994) 144. Study on transport and separation of Pb(II) through

emulsion liquid membrane by using CYANEX 272 as carrier Zou, C., Li, K. and Tong, S. Fenxi Shiyanshi, 13(3), Pages 10-12 (1994)

145. Study on transport and separation of Zn(II) from Cd(II)

and other metal ions through the emulsion liquid membrane system of CYANEX 272 - Span 80 - toluene Zou, C., Li, K. and Tong, S. Gaodeng Xuexiao Huaxue Xuebao, 15(2), Pages 185-188 (1994)

146. Synergistic extraction of rare earth elements(III) with

BTMPPA and HPMBP Sun, J. and Li, D. Yingyong Huaxue, 11(3), Pages 49-53 (1994) 147. Transport and separation of rare earth ions through the

emulsion liquid membrane of bis(2,4,4-trimethylpentyl)phosphinic acid Span 80 toluene

Li, K., Zou, C., Yao, X. and Tong, S. Zhongguo Xitu Xuebao, 12(1), Pages 6-10 (1994)

148. Application of a new extractant, CYANEX 272, to the liquid

membrane separation technology Zhang, R. and Chen, G. Mo Kexue Yu Jishu, 15(1), Pages 8-13 (1995)

149. Coupled transport of Zn(II) through a supported liquid

membrane containing bis(2,4,4-trimethylpentyl)phosphinic acid in kerosene. I. A model for the rate process involving binary and ternary complex species

Kanungo, S.B. and Mohapatra, R. J. Membr. Sci., 105(3), Pages 217-226 (1995) 150. Coupled transport of Zn(II) through a supported liquid

membrane containing bis(2,4,4-trimethylpentyl)phosphinic acid in kerosene. II. Experimental evaluation of model equations for rate process under different limiting conditions

Kanungo, S.B. and Mohapatra, R. J. Membr. Sci., 105(3), Pages 227-235 (1995) 151. CYANEX 272 complexes of some first transition metal ions

Islam, M.S. and Talukder, M.K.H. J. Bang. Chem. Soc., 8(2), Pages 105-110 (1995)

152. Diphasic acido-basic properties of di(octylphenyl)phosphoric

acid (DOPPA) Sella, C., Becis, A., Cote, G. and Bauer, D. Solvent Extr. Ion Exch., 13(4), Pages 715-729 (1995) 153. Equilibrium and non-equilibrium extraction separation of

rare earth metals in presence of diethylenetriaminepentaacetic acid in aqueous phase Azis, A., Matsuyama, H. and Teramoto, M. J. Chem. Eng. Jpn., 28(5), Pages 601-608 (1995)

154. Extraction mechanism of Th(IV) with bis(2,4,4-

trimethylpentyl)phosphinic acid from hydrochloric acid medium

Li, Q. and Li, D. Yingyong Huaxue, 12(4), Pages 58-61 (1995) 155. Extraction of europium(III), americium(III) and curium(III)

with DEHPA and CYANEX 272 Mishra, S., Chakravortty, V. and Murali, M.S.

Indian J. Chem., 34A(10), Pages 843-844 (1995)

156. Extraction of uranium(VI) from mineral acid solutions using CYANEX 272 Dogmane,S.D., Varadarajan, N., Singh, R.K., Bajpai, D.D. and Mathur, J.N. NUCAR 95: Proc. Nucl. Radiochem. Symp., Pages 132-133 (1995)

157. Extraction separation of rare earth elements(III) with

bis(2,4,4-trimethylpentyl)phosphinic acid Wang, Z., Meng, S., Song, W., Guo, C., Qi, J. and Li, D. Fenxi Huaxue, 23(4), Pages 391-394 (1995) 158. Factors influencing the efficiencies of multistage separations

of lanthanides Muralidharan, S., Ma, G. and Freiser, H. Separations of f Elements, Eds, Nash, K.L. and Choppin, G.R.,

Pages 177-197 (1995) 159. Formation of water in oil microemulsions with three dialkyl

sodium phosphinates in alcohol/isooctane mixtures Khoshkbarchi, M.K. and Vera, J.H. J. Colloid Interf. Sci., 170, Pages 562-568 (1995)

23

160. On the interaction of metal extractant reagents.

Investigation of the aggregation of di(2,4,4-trimethylpentyl)phosphinic acid and di(n-octyl)phosphinic acid in toluene by vapour-pressure osmometry

Sastre, A.M., Miralles, N. and Martinez, M. Monatsh. Chem., 126(4), Pages 401-409 (1995)

161. Purification of organophosphorus acid extractants Hu, Z., Pan, Y., Ma, W. and Fu, X. Solvent Extr. Ion Exch., 13(5), Pages 965-976 (1995) 162. Recovery of cobalt and nickel from spent

hydrodesulfurization catalysts by means of liquid-liquid extraction

Zhang, P., Inoue, K. and Tsuyama, H. Kagaku Kogaku Ronbunshu, 21(3), Pages 457-464 (1995) 163. Recovery of metal values from spent hydrodesulfurization

catalysts by liquid-liquid extraction Zhang, P., Inoue, K. and Tsuyama, H. Energy & Fuels, 9(2), Pages 231-239 (1995) 164. Recovery of molybdenum and vanadium from spent

hydrodesulfurization catalysts by liquid-liquid extraction Zhang, P., Inoue, K. and Tsuyama, H. Kagaku Kogaku Ronbunshu, 21(3), Pages 451-456 (1995) 165. Reverse micellar extraction and backextraction of L-lysine

with three dialkyl sodium phosphinates in pentanol/isooctane mixtures

Khoshkbarchi, M.K. and Vera, J.H. Sep. Sci. Technol., 30(11), Pages 2301-2314 (1995) 166. Separation and recovery of rare metals from spent

hydrodesulfurization catalysts by solvent extraction Inoue, K., Zhang, P. and Tsuyama, H. 3rd Int. Symp. on Recycl. of Metals and Eng. Mater., Pages 393-

404 (1995) 167. Solvent extraction characteristics in mutual separation of

rare earths with CYANEX 272 and TR-83 Inoue, K., Ido, N., Yoshizuka, K. and Ohto, K. Kagaku Kogaku Ronbunshu, 21(3), Pages 603-607 (1995) 168. Solvent extraction of copper by CYANEX 272, CYANEX

302 and CYANEX 301 Sole, K C. and Hiskey, J.B. Hydrometallurgy, 37(2), Pages 129-147 (1995)

169. Solvent extraction of Sc(III), Zr(IV), Th(IV), Fe(III), and

Lu(III) with thiosubstituted organophosphinic acid extractants Wang, C. and Li, D. Solvent Extr. Ion Exch., 13(3), Pages 503-523 (1995)

170. Solvent extraction of zinc(II) and cadmium(II) by CYANEX

272, 301 and 302 extractants Nayak, A.K., Mishra, P.K., Panda, C.R. and Chakravortty, V. Indian J. Chem. Technol., 2(2), Pages 111-112 (1995)

171. Solvent extraction of zinc(II) using sodium salts of D2EHPA,

PC-88A and CYANEX 272 in kerosene Devi, N.B., Nathsarma, K.C. and Chakravortty, V. Proc. Miner. Process.: Recent Adv. Future Trends, Pages 537-547 (1995)

172. Studies on the extraction of zinc(II) by CYANEX 272. II.

Extraction kinetics Sun, S., Wu, Y., Song, Q., Yang, Y., Shen, J. and Li, W. Shandong Daxue Xuebao, 30(3), Pages 312-317 (1995) 173. Studies on the extraction of zinc(II) by CYANEX 272. I.

Extraction thermodynamics Song, Q., Sun, S., Wu, Y., Yang, Y., Xin, H., Shen, J., Li, W.

and Yu, X. Shandong Daxue Xuebao, 30(1), Pages 94-99 (1995) 174. Study on the sodium salts of organophosphoric acid

extractants and their microemulsions by NMR and FTIR spectroscopy

Fu, X., Pan, Y., Xin, H.Z., Hu, Z.S. and Yu, H. Huaxue Xuebao, 53(2), Pages 178-182 (1995) 175. Testing of a bench-scale reverse osmosis/coupled transport

system for treating contaminated groundwater Hodgson, K.M., Lunsford, T.R. and Panjabi, G.

88th Annu. Meet. & Exhib., Air Waste Manage. Assoc., Pages 1-16 (1995)

176. The extraction of zinc and other minor metals from

concentrated ammonium chloride solutions with D2EHPA and CYANEX 272

Amer. S. and Luis, A. Rev. Metal., 31(6), Pages 351-360 (1995) 177. The solvent extraction of chromium(VI) from aqueous acidic

sulphate media with bis(2,4,4-trimethylpentyl)phosphinic acid (CYANEX 272)

Nahar, M.N., Islam, M.F. and Begum, D.A. J. Bangladesh Acad. Sci., 19(1), Pages 33-41 (1995) 178. Transport of metal ions in a hydrometallurgical process

using liquid emulsion membranes Gega, J. and Walkowiak, W. Hutn. Wiad. Hutn., 62(11), Pages 484-489 (1995) 179. Two-phase potentiometric metal extraction titrations of

silver(I), copper(II) and cadmium(II) using some cation-exchangers as extractants

Tait, B.K. Talanta, 42(1), Pages 137-142 (1995) 180. Analysis of the transport rates of europium(III) across an

organophosphinic acid supported liquid membrane Juang, R.S. and Lee, S.H. J. Membr. Sci., 110(1), Pages 13-23 (1996) 181. A novel separation technology for removal recovery of

metals from aqueous solutions Deorkar, N.V. and Tavlarides, L.L. Proc. Symp. Emerg. Sep. Technol. Met., Pages 107-118 (1996)

24

182. Binary mixture of PC-88A and TOPO as extractant for

thorium(IV) from aqueous HNO3 and H2SO4 media Mishra, S. and Chakravortty, V. J. Radioanal. Nucl. Chem., 207(1), Pages 53-62 (1996) 183. Coupled transport of Zn(II) through a supported liquid

membrane containing bis(2,4,4-trimethylpentyl)phosphinic acid in kerosene. I. A model for the rate process involving binary and ternary complex species

Kanungo, S.B. and Mohapatra, R. J. Membr. Sci., 118(2), Page 303 (1996) 184. CPC: tool for practical separation of metals and

fundamental investigations of chemical mechanisms Muralidharan, S. and Freiser, H. Value Adding Through Solvent Extraction, Proc. of ISEC96, 1, Pages 427-432 (1996)

185. CYANEX extractants in the recovery of cobalt from

nickeliferous solutions: Theoretical and practical considerations Rickelton, W.A. and McRae, C. Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 24 pp. (1996)

186. Distribution studies of Zn(II), Cu(II) and Cd(II) with

Levextrel resins containing di(2,4,4-trimethylpentyl) phosphinic acid (Lewatit TP80784)

Cortina, J.L., Miralles, N., Aguilar, M. and Sastre, A.M. Hydrometallurgy, 40(1-2), Pages 195-206 (1996) 187. Extraction of americium and fission product lanthanides

with CYANEX 272 and CYANEX 301 Zhu, Y., Chen, J. and Choppin, G.R. Solvent Extr. Ion Exch., 14(4), Pages 543-553 (1996) 188. Extraction of chromium(III) from spent tanning baths Pandey, B.D., Cote, G. and Bauer, D. Hydrometallurgy, 40(3), Pages 343-357 (1996) 189. Kinetic behavior of lanthanide extraction with acidic

phosphorus extractants Ma, E., Muralidharan, S., Freiser, H. and Jiang, P. J. Chem. Technol. Biotechnol., 65, Pages 81-85 (1996) 190. Murrin Murrin nickel/cobalt project: Project development

overview Motteram, G., Ryan, M., Berezowsky, R. and Raudsepp, R.

Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 28 pp. (1996)

191. Operation of a cobalt purification pilot plant

Gray, J., Price, M.J. and Fittock, J.E. Value Adding Through Solvent Extraction, Proc. of ISEC96, 1, Pages 703-708 (1996)

192. Options for the recovery of cerium by solvent extraction

Soldenhoff, K. H. Value Adding Through Solvent Extraction, Proc. of ISEC96, 1, Pages 469-474 (1996)

193. Process options using solvent extraction for the processing of

laterites Ritcey, G.M. Nickel96, Kalgorlie, Pages 251-258 (1996)

194. Recovery of rare metals from spent hydrodesulfurization

catalysts by means of solvent extraction Inoue, K., Zhang, P. and Tsuyama, H. Value Adding Through Solvent Extraction, Proc. of ISEC96, 1, Pages 745-750 (1996)

195. Separation of Co from Ni with a new generation of

extractant - CYANEX 272 Liu, D. Kuangye, 5(2), Pages 51-60 (1996) 196. Separation of scandium(III) from iron(III) and lutetium(III)

by bis(2,4,4-trimethylpentyl)phosphinic acid - N2O5 - heptane emulsion liquid membrane

Luo, A., Li, D., Kong, W. and He, Y. Fenxi Huaxue, 24(6), Pages 635-638 (1996) 197. Solvent extraction and separation of cobalt, nickel and

magnesium from a Greek laterite leach liquor Bourget, C., Cox, M. and Flett, D.S. Value Adding Through Solvent Extraction, Proc. of ISEC96, 1, Pages 505-510 (1996)

198. Solvent extraction of iron(III) from aqueous acidic sulphate

media with CYANEX 272 Islam, M.S., Islam, M.F., Begum, D.A. and Mohiuddin, M. J. Bangladesh Chem. Soc., 9(1), Pages 85-93 (1996)

199. Solvent extraction of iron(III) from aqueous hydrochloric

acid solutions using D2EHPA, PC-88A, CYANEX 272 and their mixtures

Sandhibigraha, A., Sarma, P.V.R.B. and Chakravortty, V. Scand. J. Metall., 25(3), Pages 135-140 (1996) 200. Solvent extraction of Sc(III), Zr(IV), Th(IV), Fe(III) and

Lu(III) with CYANEX 302 and CYANEX 301 from sulphuric acid media

Wang, C. and Li, D. Value Adding Through Solvent Extraction, Proc. of ISEC96, 1,

Pages 243-248 (1996) 201. Solvent extraction of thorium(IV) by CYANEX

272/CYANEX 302/CYANEX 301/PC-88A and their binary mixtures with TBP/DOSO from aqueous HNO3 and H2SO4 media

Mansingh, P.S., Chakravortty, V. and Dash, K.C. Radiochim. Acta, 73(3), Pages 139-143 (1996) 202. Solvent extraction of vanadium(IV) from sulfuric acid

solution by bis(2,4,4-trimethylpentyl)phosphinic acid in EXXSOL D80

Zhang, P., Inoue, K., Yoshizuka, K. and Tsuyama, H. J. Chem. Eng. Jpn, 29(1), Pages 82-87 (1996)

25

203. Studies on the extraction process of nickel(II) sulphate

purification using CYANEX 272 Hubicki, Z. and Hubicka, H. Hydrometallurgy, 40(1-2), Pages 65-76 (1996) 204. Swelling of polymeric resins in organic solvents induced by

dialkyldithio-containing extractants Bromberg, L. J. Phys. Chem., 100, Pages 1767-1770 (1996)

205. Synergistic extraction of rare earths based on CYANEX 272

Yuan, C., Ma, H., Pan, C. and Rickelton, W.A. Value Adding Through Solvent Extraction, Proc. of ISEC96, 1, Pages 733-738 (1996)

206. The development of a supercritical fluid extraction system

for the remediation of toxic metal contaminated environmental matrixes Smart, N.G., Elshani, S., Wai, C.M., Carleson, T. and Fox, R. Proc. Int. Top. Meet. Nucl. Hazard, Waste Manage., SPECTRUM'96, 6th, 2, Pages 967-973 (1996)

207. Theory of countercurrent extraction, XI* Calculation for

inconstant mixed extraction factor system in rare earth separation Liao, C., Yan, C., Wang, J., Jia, J., Gao, S., Li, B. and Xu, G. Value Adding Through Solvent Extraction, Proc. of ISEC96, 2, Pages 1103-1108 (1996)

208. The process of solvent extraction and the separation of

nickel and cobalt Ritcey, G.M. Nickel/Cobalt SX/EW Seminar, ALTA Metallurgical Services, Perth, Australia, 107 pp. (1996)

209. The separation of cobalt from nickel ammonium sulphate

solution by solvent extraction Feather, A.M. and Cole, P.M.

Value Adding Through Solvent Extraction, Proc. of ISEC96, 1, Pages 511-516 (1996)

210. Transition metal cation separations by organophosphorus

compounds in liquid membrane processes Walkowiak, W. and Gega, J. ACS Symp. Ser. Chemical Separations with Liquid Membranes,

642, Pages 181-193 (1996) 211. Application of the pressure acid leach process to Western

Australian nickel/cobalt laterites Motteram, G., Ryan, M. and Weizenbach, R. Hydrometallurgy and Refining of Nickel and Cobalt, 27th Annu.

Hydrometall. Meet., 1, Pages 391-407 (1997) 212. Cobalt in Africa: New developments Burks, S.F.

Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 36 pp. (1997)

213. Cobalt recovery by solvent extraction from acid leach

solutions of Carons process mixed Ni/Co sulfide Martnez, R.V., Liranza, E.G., Brzaga, B.R. and Daudinot, A.M. Hydrometallurgy and Refining of Nickel and Cobalt, 27th Annu. Hydrometall. Meet., 1, Pages 293-304 (1997)

214. CYANEX 272-loaded particles for adsorption and

separation of metal ions. I. Adsorption and separation of transition metal ions Ide, S., Haraguchi, T., Hatanaka, C., Yamada, K., Isomura, K., Takehara, K. and Hatate, Y. Kitakyushu Kogyo Koto Senmon Gakko Kenkyu Hokoku, 30, Pages 127-133 (1997)

215. Development of a hydrometallurgical process for the

recycling of metals from nickel-cadmium batteries and other similar wastes Pons, C., Nogueira, C.A., Dalrymple, I., Rodrigues, F., Delmas, F., Margarido, F. and Pena, M. 3rd ASM Int. Conf. Recycl. Met., Barcelona, Pages 489-498 (1997)

216. Development of synergistic solvent extraction system for the

recovery of nickel and cobalt from spent hydrodesulfurization catalysts Inoue, K., Zhang, P., Koga, Y. and Eguchi, H. Hydrometallurgy and Refining of Nickel and Cobalt, 27th Annu. Hydrometall. Meet., 1, Pages 221-233 (1997)

217. Extraction and separation of Mn(II) and Zn(II) from

sulphate solutions by sodium salt of CYANEX 272 Devi, N.B., Nathsarma, K.C. and Chakravortty, V. Hydrometallurgy, 45(1-2), Pages 169-179 (1997)

218. Extraction of toxic heavy metals using supercritical fluid

carbon dioxide containing organophosphorus reagents Smart, N.G., Carleson, T.E., Elshani, S., Wang, S. and Wai, C.M. Ind. Eng. Chem. Res., 36(5), Pages 1819-1826 (1997)

219. Kinetic studies on heavy metal ions removal by impregnated

resins containing di-(2,4,4-trimethylpentyl)phosphinic acid Cortina, J. L. and Miralles, N. Solvent Extr. Ion Exch., 15(6), Pages 1067-1083 (1997)

220. Liquid-liquid extraction of manganese(II) with binary

mixtures of sodium salts of D2EHPA, PC-88A and CYANEX 272 Devi, N.B., Nathsarma, K.C. and Chakravortty, V. Solvent Extr. Res. Dev., 4, Pages 117-128 (1997)

221. New nickel process increasing production at Outokumpu

Harjavalta Metals Oy, Finland Knuutila, K., Hultholm, S.E., Saxn, B. and Rosenback, L.

Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 28 pp. (1997)

26

222. QNI Limited cobalt refinery: Process development,

installation and operation Fittock, J. Hydrometallurgy and Refining of Nickel and Cobalt, 27th Annu. Hydrometall. Meet., 1, Pages 329-338 (1997)

223. Solvent extraction separation and recovery of components

from scraps containing nickel and cadmium Szilassy, I., Sumeghy, L. and Vadasdi, K. Miner. Process. Extr. Metall. Rev., 17(1-4), Pages 227-238 (1997)

224. Studies on the solvent extraction separation of americium

from fission product lanthanides Zhu, Y., Jiao, R. and Chen, J. Proc. Int. Conf. Radioact. Waste Manage. Environ. Rem., Pages 233-236 (1997)

225. Synthesis and characterization of some complexes of

copper(II), zirconium(IV), silver(I), cadmium(II) and mercury(II) with LIX 34 and CYANEX 272 Islam, M.S., Das, R.K. and Uddin, M.N.

J. Bangladesh Chem. Soc., 10(2), Pages 131-137 (1997) 226. Technical development of the Bulong laterite treatment

project Taylor, A. and Cairns, D. Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 54 pp. (1997)

227. The BioNIC process: description of the process and

presentation of pilot plant results Miller, D.M., Dew, D.W., Norton, A.E., Cole, P.M. and Benetis, G. Hydrometallurgy and Refining of Nickel and Cobalt, 27th Annu. Hydrometall. Meet., 1, Pages 97-110 (1997)

228. The treatment of cobalt/nickel solutions using CYANEX

extractants Rickelton, W.A. and Nucciarone, D. Hydrometallurgy and Refining of Nickel and Cobalt, 27th Annu. Hydrometall. Meet., 1, Pages 275-292 (1997)

229. Application of particles containing CYANEX 272 to

adsorption and separation of metal ions - II - Adsorption and separation of rare earth metal ions with particles containing CYANEX 272 Ide, S., Haraguchi, T., Hatanaka, C., Yamada, K., Isomura, K., Takehara, K. and Hatate, Y.

Kitakyushu Kogyo Koto Senmon Gakko Kenkyu Hokoku, 31, Pages 157-163 (1998)

230. CESL process for nickel-cobalt-copper sulphides testing in

an integrated pilot plant Jones, D., Hestrin, J. and Moore, R.

Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 34 pp. (1998)

231. Comparison of some aspects of the performance of a

Bateman pulse column and conventional box-type mixer/settlers Fox, M.H., Ralph, S.J., Sithebe, N.P., Buchalter, E.M. and Riordan, J.J. Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 21 pp. (1998)

232. Cu/Co tailings treatment project, Democratic Republic of

Congo Dry, M.J., Irio, G., Jacobs, D.F., Cole, P.M., Feather, A.M., Sole, K.C., Engelbrecht, J. and Matchett, K.C. Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 36 pp. (1998)

233. Direct solvent extraction of cobalt and nickel from laterite-

acid pressure leach liquors Soldenhoff, K., Hayward, N. and Wilkins, D. EPD Congr., Proc. Sess. Symp., Pages 153-165 (1998)

234. Enhanced extraction and separation of trivalent lanthanides

and yttrium with bis(2,4,4-trimethylpentyl)phosphinic acid and trialkyl phosphine oxide

Reddy, M.L.P., Ramamohan, T.R. and Iyer, C.S.P. Solvent Extr. Res. Dev., 5, Pages 1-15 (1998) 235. Extraction and separation of heavy rare earth(III) with

extraction resin containing di(2,4,4-trimethylpentyl)- phosphinic acid (CYANEX 272)

Wang, Z., Ma, G. and Li, D. Solvent Extr. Ion Exch., 16(3), Pages 813-828 (1998) 236. Extraction kinetics of Er(III) with bis(2,4,4-

trimethylpentyl)- phosphinic acid Lu, J., Ma, G., Li, D. and Ni, M. Yingyong Huaxue, 15(3), Pages 43-46 (1998) 237. Influence of the purity and irradiation stability of CYANEX

301 on the separation of trivalent actinides from lanthanides by solvent extraction

Modolo, G. and Odoj, R. J. Radioanal. Nucl. Chem., 228(1-2), Pages 83-88 (1998) 238. Liquid-liquid extraction behavior of V(IV) using phosphinc

acids as extractants Saily, A. and Tandon, S.N. Fresenius J. Anal. Chem., 360(2), Pages 266-270 (1998)

239. Separation and recovery of cobalt(II) and nickel(II) from

sulphate solutions using sodium salts of D2EHPA, PC-88A and CYANEX 272 Devi, N.B., Nathsarma, K.C. and Chakravortty, V. Hydrometallurgy, 49(1-2), Pages 47-61 (1998)

240. Separation of Am(III) from fission product lanthanides by

bis(2,4,4-trimethylpentyl)-dithiophosphinic acid (HBTMPDTP) extraction: process parameter calculation Chen, J., Zhu, Y. and Jiao, R. Nucl. Technol., 122, Pages 64-71 (1998)

27

241. Separation of nickel and cobalt from sulfuric acid leaching

solution of ocean polymetallic nodules under atmospheric pressure Jiang, X., Yin, C. and Zhou, B. Hydrometallurgy, Proc. Int. Conf., 3rd, Pages 376-381 (1998)

242. Solvent extraction and direct electrowinning of zinc from a

cobalt-bearing solution Tomlinson, M., Lommen, J. and Molnar, R. Zinc Lead Process., Eds, Dutrizac, J.E., Gonzalez, J.A., Bolton, G.L. and Hancock, P., Pages 733-747 (1998)

243. Study of f-f absorption spectra of Nd3+ - CYANEX 272

complex and Nd3+ - CYANEX 301 complex Chen, Y., Xu, J., Chen, J. and Zhu, Y. He Huaxue Yu Fangshe Huaxue, 20(1), Pages 27-35 (1998)

244. The solvent extraction of titanium(IV) from aqueous acidic

sulphate media with CYANEX 272 Mohiuddin, M., Begum, D.A., Islam, F. and Islam, M.S. J. Bangladesh Acad. Sci., 22(2), Pages 247-253 (1998)

245. Trivalent minor actinides/lanthanides separation using

organophosphinic acids Hill, C., Madic, C., Baron, P., Ozawa, M. and Tanaka, Y. J. Alloys Comp., 271-273, Pages 159-162 (1998)

246. Acid pressure leaching for the treatment of nickel cobalt

feed materials Ferron, C.J. and Swiniarski, R. Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 31 pp. (1999)

247. An investigation into the feasibility of extracting scandium

from nickel laterite ores Haslam, M. and Arnall, B. Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 18 pp. (1999)

248. Application of particles containing CYANEX 272 to

adsorption and separation of metal ions. III. Adsorption and separation of transition metal ions with particles containing CYANEX 272 Ide, S., Haraguchi, T., Hatanaka, C., Yamada, K., Isomura, K., Takehara, K. and Hatate, Y. Kitakyushu Kogyo Koto Senmon Gakko Kenkyu Hokoku, 32, Pages 177-183 (1999)

249. Characterization and evaluation of Levextrel extraction

chromatographic resins for trace metal separation schemes in automatic water quality control systems Castillo, E., Granados, M., Prat, M.D. and Cortina, J.L. Solvent Extr. Ion Exch., 17(6), Pages 1571-1586 (1999)

250. Evaluation of extractant-coated ferromagnetic

microparticles for the recovery of hazardous metals from waste solution

Kaminski, M.D., Nuez, L. and Visser, A.E. Sep. Sci. Technol., 34(6&7), Pages 1103-1120 (1999)

251. Experiences during early commissioning of the Bulong

nickel operation Framton, G.L. and Buratto, R.D. Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 19 pp. (1999)

252. Extraction of heavy metals from solid matrices with ligands

and supercritical carbon dioxide Kersch, C., Woerlee, G.F. and Witkamp, G.J. Met. Sep. Technol. Beyond 2000: Int. Nov. Chem. Proc., Eds.,

Liddell, K.C. and Chaiko, D.J., Pages 161-165 (1999) 253. Extraction studies of cobalt(II) and nickel(II) from chloride

solutions using Na-CYANEX 272. Separation of Co(II)/Ni(II) by the sodium salts of D2EHPA, PC88A and CYANEX 272 and their mixtures

Sarangi, K., Reddy, B.R. and Das, R.P. Hydrometallurgy, 52(3), Pages 253-265 (1999) 254. Extractive spectrophotometric determination of cobalt(II)

using CYANEX reagents Sarkar, S.G. and Dhadke, P.M. Can. J. Anal. Sci. Spectrosc., 44(3), Pages 75-79 (1999)

255. New flowsheet for the recovery of cadmium, cobalt and

nickel from spent Ni-Cd batteries by solvent extraction Nogueira, C.A. and Delmas, F. Hydrometallurgy, 52(3), Pages 267-287 (1999) 256. New reagents or new ways with old reagents

Flett, D.S. J. Chem. Technol. Biotechnol., 74, Pages 99-105 (1999)

257. Oxidative stability of diluents in Co/Ni solvent extraction

Maxwell, B., Rasdell, S. and Carlin, P. Nickel/Cobalt Pressure Leaching & Hydrometallurgy Forum, ALTA Metallurgical Services, Perth, Australia, 13 pp. (1999)

258. Recovery of metal values from spent nickel-metal hydride

rechargeable batteries Zhang, P., Yokoyama, T., Itabashi, O., Wakui, Y., Suzuki, T.M. and Inoue, K. J. Power Sources, 77, Pages 116-122 (1999)

259. Reversed phase chromatographic separation of

vanadium(IV) using organophosphines Saily, A. and Tandon, S.N. Indian J. Chem., 38A(12), Pages 1300-1302 (1999)

260. Selective recovery of nickel from industrial effluents by

supported liquid membranes (SLM) and modified electrodialysis (MED) De Ketelaere, R.F. and Vander Linden, J. Global Symp. Recycl., Waste Treat. Clean Technol., Pages 2223-2232 (1999)

261. Solubilization of mixed micelles formed by sodium salt of

organophosphoric acid CYANEX 272 (NaDTMPP) and nonionic surfactant AEO9 Pan, Y., Ding, Z. and Fu, X. Qingdao Huagong Xueyuan Xuebao, 20(2), Pages 122-124 (1999)

28

262. Study on ammonium ion transfer in hollow fiber membrane

extraction by on-line flow injection Zhang, F., Ma, G., Li, D., Wu, Y. and Liu, L. Yingyong Huaxue, 16(4), Pages 58-61 (1999)

263. Trace metal analysis in water quality monitoring: separation

of Zn(II) from Cu(II), Pb(II), Ni(II) and Cd(II) using impregnated resins Castillo, E., Granados, M., Prat, M.D. and Cortina, J.L. Adv. Ion Exch. Ind. Res., 239, Pages 35-40 (1999)

264. Transfer and extraction performances of erbium and

ytterbium with bis(2,4,4-trimethylpentyl)phosphinic acid in hollow fiber membranes Zhang, F., Ma, G. and Li, D. Yingyong Huaxue, 16(2), Pages 84-86 (1999)

265. Transuranic separation using organophosphorus extractants

adsorbed onto superparamagnetic carriers Nuez, L. and Kaminski, M.D. J. Magnetism and Magnetic Materials, 194, Pages 102-107 (1999)

266. An electrostatic solvent extraction contactor for nickel-

cobalt recovery Briggs, M.K., Cheng, C.Y. and Ibana, D.C. Miner. Eng., 13(12), Pages 1281-1288 (2000)

267. Bulong nickel operations post commissioning

Griffin, A. ALTA 2000, Nickel-Cobalt-6, Technical Sessions Proceedings, Perth, Australia, 12 pp. (2000)

268. Complexation of trivalent f-element ions by hard and soft

donor extractants Jensen, M.P., Bond, A.H. and Nash, K.L. Book of Abstracts, 219th ACS National Meeting, San Francisco (2000)

269. Effect of reversed micelles in Co/Ni separation by CYANEX

272 Lindell, E., Jskelinen, E., Paatero, E. and Nyman, B.

Hydrometallurgy, 56(3), Pages 337-357 (2000) 270. Extraction of Cr(III) with XAD-2 resin impregnated with

CYANEX 272 Navarro Mendoza, R., Saucedo Medina, T.I., Vera, A., Avila-Rodriguez, M. and Guibal, E. Book of Abstracts, 219th ACS National Meeting, San Francisco (2000)

271. Extraction of heavy metals from fly ash and sand with

ligands and supercritical carbon dioxide Kersch, C., van Roosmalen, M.J.E., Woerlee, G.F. and Witkamp, G.J. Ind. Eng. Chem. Res., 39, Pages 4670-4672 (2000)

272. Liquid-liquid extraction of tetravalent titanium from acidic

chloride solutions by bis(2,4,4-trimethylpentyl)phosphinic acid

Saji, J., John Saji, K. and Reddy, M.L.P. Solvent Extr. Ion Exch., 18(5), Pages 877-894 (2000)

273. Preparation and characterization of ceramic hollow

microspheres for heavy metal ion removal in wastewater Bae, E., Chah, S. and Yi, J. J. Colloid Interf. Sci., 230(2), Pages 367-376 (2000)

274. Preparation of modified silica for heavy metal removal

Kim, J.S., Chah, S. and Yi, J. Korean J. Chem. Eng., 17(1), Pages 118-121 (2000)

275. Results from the downstream unit operations of an

integrated pilot-plant campaign using the BioNIC process to produce nickel metal cathode at QNIs Yabulu refinery Nagel, V. ALTA 2000, Nickel-Cobalt-6, Technical Sessions Proceedings, Perth, Australia, 14 pp. (2000)

276. Separation of divalent manganese and cobalt ions from

sulphate solutions using sodium salts of D2EHPA, PC-88A and CYANEX 272 Devi, N.B., Nathsarma, K.C. and Chakravortty, V. Hydrometallurgy, 54(2-3), Pages 117-131 (2000)

277. Separation of Tb3+, Dy3+, Ho3+ and Er3+ with solvent-

impregnated resins containing di(2,4,4-trimethylpentyl)phosphinic acid Cui, D.L. Zhongguo Xitu Xuebao, 18(3), Pages 265-267 (2000)

278. Stripping studies of iron(III) extracted by D2EHPA, PC-88A

and CYANEX 272 from chloride solutions using sulphuric and hydrochloric acids Sandhibigraha, A., Sarma, P.V.R.B. and Chakravortty, V. Solvent Extr. Res. Dev., 7, Pages 93-105 (2000)

279. Structural studies of f-element complexes with soft donor

extractants Jensen, M.P., Bond, A.H. and Nash, K.L. AIP Conf. Proc., Plutonium Futures The Science, 532, Pages 228-229 (2000)

280. Study of the sorption of Cr(III) with XAD-2 resin

impregnated with di-(2,4,4-trimethylpentyl)phosphinic acid (CYANEX 272)

Mendoza Navarro, R., Medina Saucedo, T.I., Vera, A., Rodrguez Avila, M. and Guibal, E.

Solvent Extr. Ion Exch., 18(2), Pages 319-343 (2000) 281. Application of CYANEX 272 to Co/Ni separation

Wang, C. and Hu, F. Youse Jinshu, 53(3), Pages 1-4 (2001)

282. Application of solvent extraction in metal recovery from

spent nickel-metal hydride batteries Zhang, P., Yokoyama, T., Itabashi, O., Wakui, Y., Suzuki, T.M. and Inoue, K. Solvent Extraction for the 21st Century, Proc. of ISEC99, 1, Pages 741-745 (2001)

283. Application of supercritical fluids to the reactive extraction

and analysis of toxic heavy metals from environmental matrices system optimisation

Elshani, S., Smart, N.G., Lin, Y. and Wai, C.M. Sep. Sci. Technol., 36(5&6), Pages 1197-1210 (2001)

29

284. A structure parameter characterizing the steric effect of

organophosphorus acid extractants Zhu, T. Solvent Extr. Res. Dev., 8, Pages 85-94 (2001)

285. Cation separation in sulphate medium using solvent

extraction Moreno Daudinot, A.M. and Garca Liranza, E. Solvent Extraction for the 21st Century, Proc. of ISEC99, 1, Pages 753-758 (2001)

286. Effect of organic extractants on the electrocrystallization of

nickel from aqueous sulphate solutions Tripathy, B.C., Singh, P., Muir, D.M. and Das, S.C. J. Appl. Electrochem., 31(3), Pages 301-305 (2001) 287. Effects of some parameters on cobalt/nickel separation and

on cobalt permeation by a liquid surfactant membrane process

Salum, A., da Silva, G.L., Mansur, M.B., Miranda, T.L.S. and Ciminelli, V.S.T.

Solvent Extraction for the 21st Century, Proc. of ISEC99, 2, Pages 953-957 (2001)

288. Extraction of cadmium from phosphoric acid using resins

impregnated with organophosphorus extractants Hinojosa Reyes, L., Saucedo Medina, I., Navarro Mendoza, R., Revilla Vsquez, J., Avila Rodrguez, M. and Guibal, E. Ind. Eng. Chem. Res., 40(5), Pages 1422-1433 (2001)

289. Extraction of polonium from aqueous -hydroxyisobutyric

acid solutions using dioctyl sulphide, CYANEX 272, CYANEX 301 or CYANEX 302 in toluene Johansson, M., Malmbeck, R., Wierczinski, B. and Skarnemark, G.

J. Radioanal. Nucl. Chem., 250(3), Pages 437-443 (2001) 290. Extraction of polonium from aqueous lactic acid solutions

using dioctyl sulphide, CYANEX 272, CYANEX 301 or CYANEX 302 in toluene Johansson, M. and Skarnemark, G.

J. Radioanal. Nucl. Chem., 250(3), Pages 473-476 (2001) 291. Hollow fibre non-dispersive solvent extraction: a promising

approach to environmental and hydrometallurgical applications

Kumar, A. and Sastre, A.M. Solvent Extraction for the 21st Century, Proc. of ISEC99, 2,

Pages 1303-1308 (2001) 292. Membrane-based solvent extraction for Indium(III)-

Iron(III) separation using a Hollow fibre contactor Rodrguez de San Miguel, E. and de Gyves, J. Solvent Extraction for the 21st Century, Proc. of ISEC99, 2,

Pages 1019-1022 (2001) 293. Oxidation of CYANEX 302 and CYANEX 301 by FT-

Raman and UV-V spectroscop