Coarse silica flotation from intermediate pebble product in a dual extraction column

Coarse silica flotation from intermediate pebble (IP) product was carried out in a pilot plant dual extraction column (DEC) at an operational phosphate mine in central Florida. The solids feed rate ranged from 3.77 to 4.81 t/h (4.16 to 5.3 stph), while the amine dosages ranged from 0.16 to 0.46 kg/t (0.32 to 0.93 lb/st). The optimum amine dosage when using recycled process water was determined to be 0.3 kg/t (0.6 lb/st). With a feed containing from 40 to 45 BPL and 38% to 45% insol, the results show that the IP can be upgraded to from 56 to 61 BPL with an insol of 16% to 22% at 85% to 90% BPL recoveries. The results show that the DEC is an effective device for the flotation of coarse silica from the IP. The advantages of upgrading the IP prior blending with the pebble are presented and discussed.