iandol on sat 12 may 01
Dear Merrie Boerner,
There is a picture in E Cooper and D. Royle "Glazes for the studio =
potter" p 35 which shows the effects of heating a sprinkle of common =
salt onto a tile. The effect you got is entirely predictable. Sodium =
chloride melts at 803 Celsius (1117 F) and has a strong fluxing action =
on bisque clay with which it will react chemically. As your salt melted =
it would have been drawn into the porosity of the clay. Rising =
temperature would have accelerated the reaction and the massive area of =
clay exposed to the liquid by the porosity would have ensured a violent =
reaction. You would have been better advised to use vitrified clay tubs =
or saucers.
The following are potential reactions if you are interested. The =
volatile products I underline have been identified in industrial salt =
kiln effluent.
Sodium chloride and potash felspar to Sodium aluminium silicate and =
Potassium chloride
Sodium chloride and clay to Sodium silicate and aluminium chloride =
Sodium chloride and clay to sodium aluminate and silicon tetrachloride
Have fun with your work,
Best regards,
Ivor Lewis. Redhill, South Australia
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