Effects of silicate-bacteria pretreatment on desiliconization of magnesite by reverse flotation

摘要

Combined with silicate-bacteria pretreatment, the reverse flotation was utilized to achieve desiliconization of magnesite ore using dodecylamine as a collector. The reverse flotation experiments were conducted on magnesite ore with and without silicate-bacteria pretreatment. The reverse flotation experiments showed that the SiO2 grade of the concentrate decreased to 2.56% with silicate-bacteria pretreatment while the SiO2 grade of the concentrate was 4.61% without silicate-bacteria pretreatment. The concentrate was characterized using XRD and XRF, and the results indicated that the silicate-bacteria could dissolve the silicate minerals in the magnesite ore. The improved role of silicate-bacteria pretreatment on reverse flotation was investigated using microscopic view, zeta-potential, FTIR and SEM-EDX studies. The silicate minerals were dissolved as attested through microscopic view and FT-IR studies. Zeta potential indicated that the magnesite surface became hydrophilic by biopretreatment. SEM-EDX confirmed that there was polysaccharide secreted by the silicate bacteria attached on the magnesite surface.