Sulfur is an impurity in many common raw stoneware, fireclay, brick and earthenware clays (we have seen it as high as 5% in whole rock analyses of some earthenware clays!). During firing it forms a pungent gas that can detected in even small amounts. Sulfur dioxide is a common outdoor pollutant, it is a by-product of the burning of carbon fuels. Exposure can irritate the eyes, nose and lungs because it forms an acid when combined with moisture. Over exposure can have serious effects on the respiratory tract and ability to breathe, a doctor should be consulted.
|By Tony Hansen
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|Sulfur evolution (425-650)
Sulfur Dioxide Hazards at ilo.org
Sodium Sulfate Decahydrate
Anhydrous Sodium Sulfate
Loss on Ignition is a number that appears on the data sheets of ceramic materials. It refers to the amount of weight the material loses as it decomposes to release water vapor and various gases during firing.