RAWMATERIALS

BATCHING

MELTING

FORMING

ANNEALING

Glass Defects Jean Louis HEITZ, CRITT Matriaux Alsace

PRIMARYCONTAMINATION

raw materialproduction

delivery media(boats, cars)

raw materials storage in theglass plant

CONTAMINATION FROM BATCHING

REFRACTORY WEAR

CONDENSATEDRIPPING

BATCHING ERROR

CONTAMINATION FROM CONTACT WITH TOOLS

ATMOSPHERECONTAMINATION

PROCEDURE

Cullet : metals, porcelain, vitroceramics Lead oxide :corundum,sillimanite,metal lead

CONTAMINATION FROM :

corundum,sillimanite,chromite

corundum,SiC,iron oxides

Unmelted silica, Cords Cords Metals, Conveyor belt

Black speck(press-blow

sodalime glass, SEM )

Annealing bloom

Tin oxide condensates (float glass)

Silica batch stones

HANDLING

Sand, dolomite :heavy minerals redox contaminants

Miscellaneous :Ni -> NiS

Silicon ball from metallic aluminum

Porcelain Vitroceramic

Corundum (ruby) Nickel sulfide Reduced lead balls(lead crystal glass)

Andalousite

Chromite

Corundum (saphir)

POOR BATCH HOMOGENEITY

Temperature, pull-outFURNACE MANAGEMENT

Diopsideb - wollastonite(sodalime glass)

Unmelted silica

Devitrification stones

Volatilization

Volatilization cords(lead crystal glass)

Silica : air surface devitrification(borosilicate glass)

Fused cast, sintered, silica, electrodes, refractory metals

Cat scratches Vitreous knots

Top view (PLM) Section (SEM) AZS superstructure with secondary zirconia

(sodalime glass)

AZS glass contact in a dead water zone with

secondary wadeite(lead crystal glass)

Iron oxide flake stuckon the inner side of vessel

> revealed by acid polishing(lead crystal glass)

Primary AZS stones(lead crystal glass,

sodalime glass, SEM)

Primary silica from superstructure

(sodalime glass, PLM, SEM)

Primary tin oxide + secondary potassium tin

silicates (lead crystal glass - PLM, SEM)

Ceramic fibres(sodalime glass,

PLM, SEM)

the core of the Al Zr enriched cords is 10 m under the surface

1. Collection of data and samples in collaboration with glasswork production staff

2. Sample in-situ examination using PLM (polarizing light microscope)

3. SEM+EDX(+WDX) analysis of selected samples

Defect sorting by categories Representative defects selection for SEM analysis

Optional analyses : XRD, XRF,TOF-SIMS, ICP, etc.

5. Discussion of results with glasswork production staff

Defect reference samples Dismantled furnace reference samples

4. SynthesisComparison with proprietary database

Frictive damage on top of knurl :

smeared metal and crecsent crack

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