Recovery of boric and phosphoric acid residues from wastewater

Abstract

Residues obtained from boric and phosphoric acid factories cause some undesired environmental problems. B2O3 in sludge and reactor waste causes serious environmental problem. Recovery of B2O3 and P2O5 are important processes in the prevention of water pollution and the utilization of waste mud. Both residues include mainly borogypsum, phosphogypsum and impurities. In order to recover B2O3, Li, P2O5, F and other water‐soluble constituents, the residues were extracted at different temperatures with water, and by lime milk. P2O5 and F remove completely from wastes by washing with milk of lime. 47% of B2O3 is removed by extracting with hot water.