PRODUCTION OF 22TYPE HEMIHYDRATE GYPSUM OF NEEDLEELIKE CRYSTAL FROM PH OSPHORIC ACID BYYPRODUCT DIHYDRATE GYPSUM

摘要

PURPOSE:To easily obtain alpha-type hemihydrate gypsum of needle-like crystal even when the mother liquor is recycled, by preparing gypsum slurry from phosphoric acid by-product dihydrate gypsum and water, heating, and reacting the slurry while maintaining the pH at specific value in acid side.