A Mine Flotation of Chromite Ores from the Stillwater Complex, Montana.
Smith-GE; Huiatt-JL; Shirts-MB
The Bureau of Mines, U.S. Department of the Interior, devised a flotation technique for upgrading chromite in chromium ores and gravity concentrates. The technique consisted of cationic flotation of chromite from a slime-free pulp acidified to ph 2.5 Or lower using h2so4 modifier. Flotation results showed that ore containing serpentine as the primary gangue mineral was more amenable to concentration by this technique than ore containing the readily flotable olivine as the primary gangue mineral. Rougher flotation of a chromite ore containing abundant serpentine increased the grade form 19 to 41 percent cr203 at a chromite recovery of 89.6 percent. Rougher flotation of ore containing abundant olivine upgraded the chromite from 23.4 to 29.6 percent cr2o3 at a recovery of 89.4 percent. The technique was also applied to chromite gravity concentrates to further upgrade chromite and to reject silicates. Flotation of a gravity concentrate containing 40.9 percent cr2o3 and 4.4 percent sio2 recovered 90 percent of the chromite in cleaner products containing 44.9 percent cr2o3 and 0.63 percent sio2. The combined recovery by gravity and flotation was 87 percent. An economic evaluation of this technique will be undertaken to determine its feasibility for commercial use.
IH; Report of Investigations