Optimization flotation studies on a phosphorite sample from Jhamarkotra, Udaipur district, Rajasthan, India

The consumption of sodium oleate collector and depressant phosphoric acid was exceeding the design test values by 30% in a phosphorite flotation plant at Jhamarkotra. Extensive flotation tests on typical mill feed sample (High pressure roll crusher—screen circuit) were conducted using plant’s reagents simulating plant conditions. Controlled closed circuit grinding minimizing slimes generation, thick pulp conditioning with just starvation dosages of sodium oleate collector in bulk flotation of phosphates and carbonates, intensive thick pulp conditioning with phosphoric acid for selective depression of phosphates from collector coated alkaline earth salt minerals at pH 5, followed by differential flotation of carbonates were found to be critical, for process selectivity and reduction in dosages of sodium oleate and phosphoric acid by 60 and 30% respectively. Concentrate assaying >32% P2O5, with >80% P2O5 distribution meeting specification was obtained with 0.34Kg/t sodium oleate, 4.3Kg/t phosphoric acid and 10 Kg/t sulphuric acid simulating the plant flow sheet, for adaptability in the plant.