Phosphogypsum treatment in quenching bath contg. sulphates - to improve suitability for use as building plaster

摘要

Phosphogypsum is allowed to stand for several hours (6-8 hrs) in a quenching bath contg. an aq. metallic sulphate esp. potassium alum, then dried and calcined in a furnace at 200-1100 degrees C pref. after drying. The prod. is used for making plaster for the building industry. The alum counteracts the effect of any residual phosphoric acid in the gypsum improving the props. of the cement.