Treatment of sodium tungstate leach liquor containing dissolved silica, phosphorus, and fluorine impurities

摘要

Basic sodium tungstate leach liquor is treated to reduce the concentration dissolved therein of silica, phosphorus and fluorine impurities in a process which comprises providing a small but effective amount of magnesium in the liquor to maximize removal of silica and phosphorus from solution in the liquor while maintaining the liquor temperature between about 60 DEG C. and about 100 DEG C. and the liquor pH between about 9 and about 11, filtering the liquor, adjusting the liquor pH to between about 6 and about 8 and the liquor temperature to between about 20 DEG C. and about 60 DEG C., and then providing a small but effective amount of aluminum hydroxide in the filtered liquor to maximize removal of fluorine from solution in the liquor while maintaining the liquor temperature between about 20 DEG C. and about 60 DEG C. and the liquor pH between about 6 and about 8.