INTEGRATED PROCESS OF PRODUCTION OF POTASSIUM SULPHATE AND AMMONIUM SULFATE FROM KAINITE MIXED SALT

摘要

The present invention provides an integrated process for the recovery of sulphate of potash (SOP) and ammonium sulphate fertilizers from kainite mixed salt dispensing with magnesium hydroxide production. The process comprises, among other steps, producing calcium chloride from calcium carbonate through addition of hydrochloric acid; the calcium chloride being used for desulphatation of schoenite end liquor (SEL) obtained as liquid stream during decomposition of kainite mixed salt with water to obtain solid schoenite; using the resultant gypsum and carbon dioxide together with ammonia for the production of ammonium sulphate liquor and solid calcium carbonate, the latter being recycled in the process; producing camallite from desulphated SEL; decomposing the camallite to recover camallite decomposed product (CDP) which is further refined under ambient conditions to obtain pure potassium chloride (KC1) utilised in the preparation of SOP from the schoenite. Except for ammonium sulphate recovery in solid state, where required, all operations are carried out at ambient temperature.