Willemitic ore flotation using Bacillus subtilis as a depressant

The use of microorganisms in mineral processing has become an increasingly researched and explored field of biotechnology, thanks to the economic and environmental benefits of this approach, although it is still an area that requires more in-depth research. Flotation tests in a bench-scale mechanical cell were carried out with the microorganism Bacillus subtilis as a depressant of dolomitic gangue in the willemite flotation. Two dosages of the depressant were tested (500 g/t and 2,000 g/t) and the yield, metallurgical recovery, and zinc content results were compared with results from a reference test carried out according to the standard of the company that donated the zinc ore. The use of the depressant at a dosage of 2,000 g/t produced results that were statistically different and superior to the standard test, which suggests that the use of the microorganism increased the flotation selectivity. (author)