A PROCESS FOR THE PRODUCTION OF HYDRATED ALUMINIUM FLUORIDE (A1F33H2O) FROM SCUBBER LIQUORS OBTAINED FROM PHOSPHATIC FERTILISER INDUSTRY

摘要

A process for the preparation of hydrated aluminium fluoride (ALF3. 3H2O) from scrubber liquor obtained from the phosphatic fertilizer industry containing 12-20 percent hydro fluosilicic acid (H 2 SlF 6) and 250-300 mg per litre of P2 O5 comprising the steps of reacting it with hydrated alumina at 90-100degreeC, removal of the precipitated silica and crystallization of the aluminium fluoride in solution as the beta AlF3, 3H2O at 90-95 degree Celsius and separation of the said AlF3, 3H2O from the mother liquor, characterized in that only 90-95 percent of the stochiometric quantity of hydrated alumina required for reacting with the fluorine is added and the transformation of the alpha form of the aluminium fluoride to the beta form is effected at a pH of 1.0 by the additions of a mineral acid.