"The Bureau of Mines conducted tests on samples of two Florida phosphate slimes to devise a technique to recover phosphate currently discarded because of its fine size. A flotation technique was devised to recover the phosphate contained in two fractions of each slime: the plus 37-um fraction and the plus 20-um fraction. The technique involved conditioning the flotation feed with sodium silicate and a fatty acid-fuel oil emulsion, floating a rougher phosphate concentrate, and cleaning the concentrate in two cleaner stages with sodium silicate added to each for gangue depression. Concentrates containing 21.0 to 32.3 pct p2o5 were produced with recoveries of 68.1 to 84.2 pct of the p2o5 contained in the flotation feed." - NIOSHTIC-2 NIOSHTIC no. 10005851

National Institute for Occupational Safety and Health