iandol on fri 12 jan 01
Dear Jo Ann,
I cannot say anything about ITC, but it would seem that your firebricks =
have a good percentage of Iron in them. It is not unusual for clay to =
contain Pyrites, Iron sulphide. This reacts strongly with molten sodium =
chloride releasing Ferric chloride. Ferric chloride will react with =
slips an light colouring clays.
I attended a workshop with Jane Hamlyn. The kiln had been constructed =
for the workshop and had not been fired with salt. All the clays were =
chosen to be light firing. The first salting caused everything turned =
very dark. As you may imagine, everyone was bitterly disappointed, Jane =
most of all.
Part of the problem rests with the people who continue to insist that =
salt and water react to give free chlorine and sodium ions. This is =
unproven, I regard it as nonesense. Research work done by the British =
Ceramic Society almost fifty years ago shows that something very =
different must be happening. I think there is an exchange reaction when =
Sodium chloride melts on the pots and mixes with the silicate from the =
flux. The result is the discharge of Potassium chloride, Iron chloride, =
Aluminium chloride and Silicon tetrachloride. This was reported in two =
private research papers which were not published by the BCS.
Hope you solve your problem ,
Best regards,
Ivor.
Stephen Grimmer on sun 14 jan 01
Ivor,
Fascinating stuff. Is there any published information on this research?
It would go a long way toward explaining the behavior of iron in clays in
salt kilns. What is the reaction when sodium carbonate is introduced?
--
Stephen Grimmer
Southern Illinois University at Carbondale
> From: iandol
> Part of the problem rests with the people who continue to insist that salt and
> water react to give free chlorine and sodium ions. This is unproven, I regard
> it as nonesense. Research work done by the British Ceramic Society almost
> fifty years ago shows that something very different must be happening. I think
> there is an exchange reaction when Sodium chloride melts on the pots and mixes
> with the silicate from the flux. The result is the discharge of Potassium
> chloride, Iron chloride, Aluminium chloride and Silicon tetrachloride. This
> was reported in two private research papers which were not published by the
> BCS.
>
> Hope you solve your problem ,
> Best regards,
> Ivor.
>
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