IMPROVING FLOTATION OF LOW-GRADE PHOSPHATE ORE BY ATTRITION

摘要

Separation of carbonate impurities from phosphate by flotation seems to be a more difficult task due to the similarities in their surface properties. In addition, the comminution process for carbonates, being friable minerals, results in coating of the phosphate particles surface. Thus, in this paper, the attrition process was conducted separately or combined with the flotation process using oleic acid as the collector and phosphoric acid as the depressant at pH 4.5. The attrition step followed by flotation was employed to clean the surface of both phosphate and carbonate particles and facilitate collector adsorption. The results indicate that, using either flotation or attrition alone in upgrading such ores, a concentrate containing 27~28 % P_2O_5 may be obtained. On the other hand, when using the attrition followed by flotation, the phosphate grade exceeds 31 % P_2O_5.