0 5 10 15 20 250.0

0.5

1.0

1.5

2.0

2.5

solid

/gL

-1

Time/ hr

Origin solid content=85g/L

DI-water Alcohol Acetone

0 5 10 15 20 250

2

4

6

8

10

12

14

16

18

20

Origin solid content=150 g/L

so

lid/g

L-1

Time/ hr

25OC 40OC

Origin Acetone Alcohol Water Oil

<1000NTU

<1000 NTU

762NTU

7.2NTU

0.5 NTU

Solar EnergyRenewable,Abundant,

clean and readily available Yu-Pei Shih

Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei, Taiwan.

Advantages of liquid-liquid phase separation: Without the equipments for vacuum or the formation of steam Prevented pyrolysis Fast & simple equipment Recycled the water Removed the small size particles

In silicon wafer manufacturing, silicon ingots must be cut by multiple wiresaws with an abrasive slurry composed of SiC particles in a glycol oil. This silicon waste drains away with the slurry. In the world at least 3000 ktons of silicon waste is generated and this glycol oil drains away with the slurry. However, the glycol oil in sawing waste can be as high as 45% by weight. Therefore, a sufficient recovering glycol oil from silicon waste could yield enough glycol oil to support silicon solar cell production and reduced pollution.

2. The solid-liquid separation

Part 1- Centrifugation separation(3000 g / 5500 rpm / 25 &40 )℃ ℃

Part 2- Centrifugation separation with 50 wt% dilutes.(3000 g / 5500 rpm / 25 )℃

3. Liquid-Liquid separation

Recovered glycol oil may be reuse to silicon cutting process.

1. What is silicon waste??

0.1 1 10 100

0

2

4

6

8

10

particle size (m)

volu

me/

%

Difficulty: Particles suspended stability High viscosity of waste With a lot of small size particles

4. The properties of glycol oil

Part 1- Appearance

How can I do to recovery the

glycol oil from silicon waste?!

Part 2- Newtonian fluid

origin

recovery

Part 4- GC Analysis

Part 3- Suspension

Origin 25℃ 40℃ Oil

<1000NTU

<1000NTU

7.2NTU

0.5 NTU

Controlled by: Viscosity & hindered effect Removal small size particles

For origin oil Suspension solids =0 g/L Turbidity= 0.5 NTU

For origin oil Suspension solids =0 g/L Turbidity= 0.5 NTU

-20 0 20 40 60 80 100 120 140 160

0

10

20

30

40

50

60

70

80

90

100

0

10

20

30

40

50

60

70

80

90

100

temperature/ 0C

wat

er/ w

t.%

Time/ min

Simple distillation water content oil phase temperature

liquid-liquid separation water content oil phase temperature

Compared ability of removal water by simple distillation & phase separation:

Electrochemistry Process Waste Reduction LabCentrifugation with

50 wt% water. (3000 g / 6 hr/ 25 )℃

oil & water mixing

=particles

oil & water separation

Rich water phase

Rich oil phase

hydrogen bonds

0 2 4 6 8 10 12 140

1

2

3

4

5

6

7

origin recovery

shea

r stre

ss(N

m-2

)

shear rate(s-1)

OriginRecycling

Recovery of Glycol oil from Silicon Waste