Infrared Spectroscopic Studies of Calcium Sulphate heated to High Temperatures

Abstract

Infrared spectroscopic investigations have shown that on the basis of changes in the vs, SO4band which occur when calcium sulphate is heated from 400° to 1400 °C, there are two forms of insoluble anhydrite, designated as ‘-’ and β-CaSO4. β-CaSO4is metastable and is completely converted into β-CaSO4by heating above 1000 °C. With longer heating periods this conversion can even take place at lower temperatures. β-CaSO4is stable and is of the same type as the naturally occurring form of anhydrite. © 1971, Walter de Gruyter. All rights reserved.