Anhydrite III or approximatelya stabilised by heat treatment, its method of production and an installation for its industrial scale production

摘要

A method for the production of anhydrite III or alpha , stabilised by heat treatment of a pulverised material with a base of hydrated calcium sulphate (CaSO4, 2H2O), comprises the following stages:- a) heating the pulverised material at a temperature between 220oC and 360oC to transform hydrated calcium sulphate to soluble anhydrite III or a; and b) subjecting the transformed material to a thermal quenching to a temperature at least below 110oC, preferably below 80oC and preferably within two minutes, to produce the stabilised anhydrite III or alpha . The ambient humidity in contact with the transformed material is evacuated before and during the second stage (b) of the method. An independent claim is included for an installation for the production of anhydrite by this method. A further INDEPENDENT CLAIM is included for the stabilised anhydrite III or alpha anhydrite produced by this method.