PROCESS FOR THE SIMULTANEOUS PRODUCTION OF SODA ASH AND AMMONIUM CHLORIDE.

摘要

WE CLAIM U) A cyclic process system for the simultaneous production of soda ash and ammonium chloride utilising an equilibrium solution of sodium chloride, ammonia and carbon dioxide, in which a carbonated mother liquor of the starting materials is subjected to a single ammoniation step, sodium chloride (common salt) is added to the ammoniated liquor at a temperature above 35C, preferably 40 to 42C, in order to maintain solubility of the sodium chloride in the liquor, the ammoniated salt-containing liquor is now subjected to two-stage crystallisation whereby ammonium chloride crystallises and the slurry of crystals thus formed is centrifuged and dried, the ammonia vapours of high ammonia content evolved in the first stage of crystallisation are absorbed in the liquor remaining in the crystallisation section after removal of the ammonium chloride in order to maintain the high ammonia content of such liquor, the said liquor is subjected to carbonation by means of high purity carbon dioxide in a series of reactions, the sodium bicarbonate resulting from this reaction is separated and subjected to calcination whereby the sodium bicarbonate is converted to sodium carbonate, i.e. soda ash.