STVC on wed 21 feb 01
Although I have only reviewed a small number of documents, 1000 degrees C
seems to be the consensus calcination temperature to produce bone ash.
Anita's previous article suggested 600 degrees C at 5 to 15 minutes was the
outer limit of prion "template" survivability. It seems logical to assert
that commercially prepared bone ash most probably poses little risk.
If you really want to be safe, you can recalcine your bone ash in your kiln.
Any temperature between cone 020 and 03 should be sufficient.
Steven Van Cleave
Vista, CA
Michael Tannock on thu 22 feb 01
Hi,
W Ryan and C Radfords Whitewares Production Testing and Quality Control
mentions that the calcining temp for bone ash is 900 deg. C. Still well
over 600 degrees however.
The calcining temp of bone ash, according to this book pp. 11-12, alters the
characteristics of a bone china slip body, lower calcining temp giving
stronger but slower casts as there is more organic residue. Calcined higher
the slip is faster casting but more brittle as greenware.
If the bone ash is used for bone china production it may be as well to be
aware of this. The above book is really good... with lots of body
formulations and practical suggestions for the control of them. It is
published by pergamon press, 1987.
Mike Tannock
Dunedin NZ
>seems to be the consensus calcination temperature to produce bone ash.
>Anita's previous article suggested 600 degrees C at 5 to 15 minutes was the
>outer limit of prion "template" survivability. It seems logical to assert
>that commercially prepared bone ash most probably poses little risk.
>
>If you really want to be safe, you can recalcine your bone ash in your
>kiln.
>Any temperature between cone 020 and 03 should be sufficient.
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Roger Korn on sat 24 feb 01
I've experimented with this, by measuring loss of mass when calcining
bones to various temperatures. After 1100C, no more weight loss, so
Steve Van Cleave's suggestion of 1000C is pretty close to optimum.
Roger Korn
McKay Creek Ceramics
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