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Characterization

of fused cast refractories

regarding their glass defect

formation behaviour

Michael Dunkl Dr. M. Dunkl Consulting, Dsseldorf, Germany

Jean-Piere MeynckensAGC, Belgium

Janusz Zborowski AGH, University of Science and TechnologyCracow, Poland

123rdInternational Congress on Glass, Prague, 2013

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Outline

1. Introduction

Characterisation of fused cast refractories regarding their glass defect formation behaviour

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Outline

1. Introduction

2. Test methodsevaluating glass defect formation potential of refractories

2.1 Corrosion test2.2 Cords formation test

2.3 Blistering test

2.4 Exudation test

Characterisation of fused cast refractories regarding their glass defect formation behaviour

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Outline

1. Introduction

2. Test methodsevaluating glass defect formation potential of refractories

2.1 Corrosion test2.2 Cords formation test

2.3 Blistering test

2.4 Exudation test

3.Conclusions

Characterisation of fused cast refractories regarding their glass defect formation behaviour

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Interrelations in glass defect formation process

corrosion

properties ofrefractory

glassquality

glass

defects

parameters of

melting process

constructionof melting unit

properties of

glass melt

parameters of

interaction

between glassmelt and

refractory

flow

parameters

Introduction

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Corrosion tests

Static plate corrosion test as recommended by TC11 of ICG

Experimental procedure

RT240 h / 1650 C

Pt/Rh-crucible 140 mmQuarzal-crucible

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Test methods

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Corrosion tests

Static plate corrosion test as recommended by TC11 of ICG

Experimental procedure

RT240 h / 1650 C

Pt/Rh-crucible 140 mmQuarzal-crucible

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Test methods

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What kind of information

regarding glass defect formation potential

we can expect from corrosion test ? (1)

Microstructure of reaction layer: FC AZS/borosilicate glass

after static plate corrosion test

100 m

100 m

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thickness

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What kind of information

regarding glass defect formation potential

we can expect from corrosion test ?(2)

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Modified static plate corrosion test

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Additional possibilities of evaluation:qualitative assessment of glass defect formation potential,

microscopic and EDX analysis of defects

Test methods

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Cord formation test

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Test methods

Crucible test:

- temperature change (e. g. 15501000 - 1550C)

enhancing the formation of all kinds of defects

(cords, stones, blisters)

- evaluation of the polished plate cut from middle of the crucible

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Blistering testwith glass melt refreshing and continuous observation

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video camera

lampmiror

refractory crucible

heating element

Test methods

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Blistering testcomparison of blistering behaviour

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Dynamic blistering test: AZS and HZFC with borosilicate glass at 1500C Blistering rate

0

5

10

15

20

0 48 96 144 192 240 288 336 384

test time [h]

Blis

teringrate[1/cmh],

6h-value

ZB-X950

ER 1711

HZFC

AZS

Test methods

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Test methods

Exudation test

Methodsample

shape

sample

dimensionsprocedure

evaluation/

remarks

cylinder1 inch (diameter)4 inch (hight)

bar 1 x 1 x 4 inch

A30 mm (diameter)

30 mm (hight)

1 heating cycle

16 h soaking

at 1500 C

calculation of

sample's

volume change

B disc25 mm (diameter)

3 mm (hight)

1 heating cycle

16 h soaking

at 1500 C

calculation of

sample's

volume change

TC 11 bar 50 x 50 x 100 mm

up to 10 heatingcycles

1st cycle 72h

soaking

further cycles

2h soaking at

1550/1650C

determination

of

volume/weight

of

adhering glassy

phase

1 heating cycle4h soaking at

1510 C,

2 further cycles

possible

ASTM

C1223-92

calculation of

sample's

volume change

T h d

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Test methods

Method A

"Glass

Exudation"

[%]1 cycle 1500 C 1 cycle 9 cycles 1 cycle 6 cycles

AZS 36reduced exudation 1,1 - 1,6 1,2 3,1 4,5 - 6,7 6,3 - 7,1

AZS 41 0,9 - 1,8 0,7 - 2,0 1,8 - 4,8 4,9 - 7,4 7,8AZS 32 1,0 -1,8 0,7 - 3,0 6,8 - 8,3 8,5 - 11 9,8 - 11,6

TC 11 method

1550C 1650C

Sample

T t th d E d ti t t lt i t t ti / i

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(Some) Fundamental statementsconcerning testing and the results interpretation

of lab exudation testcarried out on as delivered materials under air atmosphere

1. Sampling representativity and

test method/conditionscomparabilty

have to be ensured

2.lower amount of glass phase in FC AZS

less exuded glass phase

3.lower exudation lower defect potential

because

4.exudation testis nota corrosion test

Test methods: Exudation test results interpretation/meaning

T t th d

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Conclusions

1. Standard and modified corrosion tests as well as cords formation

tests combined with additional macro- and microscopic

investigations are able to provide a valuable assesment of glass

defect potential of a refractory/glass melt system

2. To estimate the glass defect potential of FC refractories

associated with their exudation behaviour

properly

it have to be kept in mind that:

- what we determine in lab in the exudation test is not directly

transferable on behaviour in a glass tank (corrosion process),

- to evaluate and to compare the exudation data the sampling

and test method parameters have to be known in detail

and comparable

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Test methods

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hank youfor your attention

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