METHOD FOR PREPARING BINARY ZINC-CONTAINING SUPERPHOSPHATE Russian patent published in 2003 - IPC

FIELD: inorganic chemistry, chemical technology. SUBSTANCE: invention relates to production of mineral fertilizers enriched with trace elements, in part, zinc and providing the enhanced resistance of plants to environment. Waste from viscose manufacture formed after deoxidation of flows by lime method are used as component for preparing binary superphosphate. Flows are treated with phosphoric acid as measured 1.217-1.304 kg of crystalline H₃PO₄ per 1 kg of waste with natural humidity 15.9-17.0%. Zinc-containing waste from viscose fiber manufacture obtained by deoxidation of sewage by lime method have the following composition, wt.-%: CaSO₄. 26-33; Ca(OH)₂, 36-38; Zn(OH)₂, 10-12; organic matters, 14-15.5; other components, 7-8.5; crystalline H₃PO₄ before using is dissolved in water up to the concentration 25-45%. EFFECT: reduced industrial consumptions, enhanced quality of superphosphate. 3 cl