bioflotation of apatite using bacillus and pseudomonas bacteria

Due to the increase of phosphate uses in the agriculture, food industry, energy production and military industries, and the reduction of high-grade phosphate reserves in the world, it is essential to upgrade the low-grade phosphate resources. the flotation method has been used as the most efficient method for separating phosphate minerals, especially apatite. in this process, the use of chemical agents as collector, activator and depressant is unavoidable. today, the use of bioflotation has received more attention in order to reduce the consumption of chemicals and environmental problems. in this regard, the floatability of apatite and the gangue minerals including hematite, dolomite, and quartz in the presence of bacillus cereus, pseudomonas, and bacillus subtilis bacteria was investigated in the present study. the recovery rates of apatite and dolomite decrease in the presence of bacillus subtilis, bacillus cereus, and pseudomonas, indicating that bacillus subtilis acts as a depressant. additionally, it was observed that the presence of bacillus subtilis, bacillus cereus, and pseudomonas had no effect on the surfaces of hematite and quartz. with an increase in time, the recovery rate of apatite increases, and the effect of bacillus subtilis, bacillus cereus, and pseudomonas as depressants on the minerals decreases.