METHOD FOR PROCESSING PHOSPHOGYPSUM TO AMMONIUM SULFATE AND CALCIUM CARBONATE

摘要

The invention relates to a method of processing phosphogypsum – phosphate production residues to ammonium sulfate ((NH)SO) used in chemical industry, e.g. in manufacturing fertilizers, and to calcium carbonate (CaCO). A method of processing phosphogypsum to ammonium sulfate and calcium carbonate comprises interaction of phosphogypsum with ammonium carbonate solution and treating the pulp by carbonic acid with subsequent separation of calcium carbonate and ammonium sulfate by filtration. The pulp is treated with the carbonic acid the pulp is cooled to 35-45°C, the carbonic acid is taken in the amount of 50-70% from stoichiometry on CaO and then prior to filtration the obtained reaction mass is heated to 75-95°C.