John Falconer Byrd on wed 5 jun 96
I am curious about the chemical make up of the fossilized diatom shells
mined in the California area. Is it a form of free silica? These ground
remains are often used as a paint additive and I was curious about using
them as a mica-like additive to a hi-fire clay body. Does anyone know if
it is refractory to any extent? Where might I obtain some? Thank you,
John Byrd-
Ron Roy on thu 6 jun 96
>----------------------------Original message----------------------------
>I am curious about the chemical make up of the fossilized diatom shells
>mined in the California area. Is it a form of free silica? These ground
>remains are often used as a paint additive and I was curious about using
>them as a mica-like additive to a hi-fire clay body. Does anyone know if
>it is refractory to any extent? Where might I obtain some? Thank you,
>John Byrd-
From Ceramic Industry Handbook - Jan 95
85.3 SiO2
5.4 Al2O3
1.1 Fe2O3
1.1 CaCO3 (calcium carbonate)
5.6 H2O
This is a typical analysis so any attemp to use this material should be
preceded by a more specific ananysis. Make sure the grind is fine.
Warning !!! This material forms cristobalite above 1950F
Frankly I would not use this stuff in any clay or glaze but I would like to
hear from anyone who has used it - always willing to change my mind in the
face of a repeatable experiment.
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
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