Effect of biological pretreatment on flotation recovery of pyrolusite

Bacillus mucilaginosus was used in pretreatment of pyrolusite to facilitate the flotation removal of quartz from pyrolusite minerals. Quartz was activated by B. mucilaginosus, whereas pyrolusite was unaffected at pH 7 with laurylamine as collector. Flotation recovery of pyrolusite with B. mucilaginosus pretreatment is 73.62%, slightly lower than that of the process without biopretreament, namely 74.70%. The grade of concentrate of recovered pyrolusite is 19.44%, 2.18% higher than that of the recovered pyrolusite without B. mucilaginosus pretreatment (17.26%). The results of FTIR and SEM showed that no bacteria were adsorbed on the surface of quartz or pyrolusite, indicating that the better selectivity and collectability of flotation resulted from bacterial byproducts. And interaction of bacterial byproducts such as extracellular bacterial polysaccharide, extracellular bacterial protein and acetic acid, on minerals were studied by FTIR and adsorption.