METHOD FOR EXTRACTION OF BORON AS BORATES FROM ULEXITE Russian patent published in 1996 - IPC

FIELD: production of boric acid. SUBSTANCE: ulexite ore is brought into contact with sulfuric acid and with mother solution, the process is carried out at 120-200 C at pH of thus prepared suspension within 9-12. Mass ratio of H₃BO₃/Na₂O, in aforementioned mother solution is 1.5-3.5:1. Thus prepared suspension is filtered, calcium borate is separated as solid phase of it, sodium borate being crystallized of filtrate. Sodium hydroxide is added into mother solution after crystallization to predetermined ratio H₃BO₃/Na₂O. pH of suspension is sustained within 11-12, mass ratio H₃BO₃/Na₂O being sustained within 2.0-2.5. Crystallization of sodium hydrate is carried out by sustaining solution at 30 C, decahydrate of sodium borate being prepared. EFFECT: improves efficiency of the method. 4 cl, 1 dwg