Method of beneficiating phosphate ores containing dolomite

摘要

A method of beneficiating a phosphate ore containing silica and an alkaline earth metal carbonate impurity, particularly dolomite or calcite. The steps include testing the ore for excessive levels of carbonate impurities, the use of conventional flotation steps to remove silica, grinding the ore to a particle size in which at least 90% of the ore particles are less than 0.355 mm and thereafter reagentizing the ground phosphate containing ore with water, a carbonate collector, a phosphate depressant and a pH regulator to obtain a flotation feed having a solids level of about 20-30% and a pH of about 5.6-6.0. The flotation feed is then subjected to a reverse flotation in a flotation cell to remove carbonate impurities as the cell overflow and to collect a phosphate concentration as the cell underflow.