Technical note evaluation of flotation strategies for sedimentary phosphates with siliceous and carbonates gangues

摘要

Different flotation strategies to separate bothcalcite and silica from a sedimentary phosphate ore are studiedin this paper The results show that a single stage for flotation ofphosphate or calcite is not enough to obtain high gradeconcentrates. Among three different processes for carbonateflotation, the results reveal better selectivity when phosphoricacid is used as depressant for phosphate. A circuit consists of aflotation stage for carbonate and another for either phosphate orsilica presents the best strategy for upgrading such ore.Separation of calcite in the first stage seems to be essentialwhere the selectivity margin tends to operate in favor ofcarbonate rather than phosphate mineral. Concentrates withP_2O_5 above 30percent are obtained while using such flotationstrategy from a feed ground to -a 15 mm.