IS 1288 (1982): Methods of test for mineral gypsum. 21/05/1982 This standard prescribes methods of test for mineral gypsum. It covers the methods for determination of fineness, free water, combined water, carbon dioxide, silica and acid insolubles, iron and aluminium oxides, calcium oxides,, magnesinm oxides, sodium chloride, sulphur trioxide, and various forms of .
The double salt crystals may be separated and converted to chalk; and may be reacted in an aqueous solution to precipitate gypsum which may be converted to chalk. The method is designed to produce high quality gypsum, primarily calcium sulphate dehydrate. GBA Method of producing high purity gypsum Google Patents Method of .