PROCESSING EQUIPMENT AND METHOD FOR A PULVERULENT CALCIUM SULPHATE MATERIAL AND NOVEL HYDRAULIC BINDER

摘要

A method for processing a pulverulent calcium sulphate material in order to obtain a hydraulic binder is described, including combining the following two successive processing steps: (a) heating the pulverulent material in a curing tunnel (1) at a temperature of 220-360° C., under conditions suitable for primarily forming an alpha-type calcium sulphate, and (b) subjecting the heated material to a thermal quenching step in a cooling apparatus (2), with a cold, dry gas to stabilise the alpha anhydrite and to prevent its conversion into other crystallographic types. The method provides a novel hydraulic binder with an alpha anhydrite content of more than 35 wt. %, and with improved strength and behavior in fire resistance properties.