The Effect Of Inhibiting Clay Dispersion On Coal Flotation

Clay is the major gange mineral in coal,and major ash mineral. When the clay minerals encounter with water, they expand and strip into micron grade crystal layer particles, thus influence flotation. Inhibition is aimed at inhibiting the dispersion of clay minerals through changing the solution chemistry once clay minerals encounter with water.Research on this area had been devoloped in coal slime treatment. Inhibition inevitably influence flotation.In this paper, montmorillonite and kaolinite were respectively compounded with pure coal as the object for the study, adopted Ca2+ and TMBAC as inhibitors, then respectively studied the impact dicipline of the two kinds of inhibitors inhibiting the two clay minerals on flotation. In the interest of studying the impact mechanism of these kinds of inhibition on flotation, particle size measuremen,Zeta potential test and rheological properties test of slurry were conducted.For montmorillonite-coal system, under the condition of Ca2+ inhibition and non-inhibition, in pace with the Ca2+ concentration increases, the combustible recovery and the concentrate ash increased. Under the condition of inhibiton, the combustible recovery reach up to 92.58 %,the concentrate ash was 5.20 %,while under the condition of non-inhibitition,the combustible recovery was 81.13 %, the concentrate ash was 4.79 %. The reason was that under the condition of inhibitition, there are more particle aggregates, with the slurry viscosity increased, the flow became non-Newtonian flows from Newtonian flows, this would favor improving the stability of the foam layer,thus increases the combustible recovery.For kaolinite-coal system, with increasing of Ca2+ concentration, the change of combustible recovery and concentrate ash was the same to montmorillonite-coal system,but the opposite result.When the Ca2+ concentration was higher than 5 mmol/L, under the non-inhibition condition,combustible recovery reache up to 85.59 %,the concentrate was 7.01 %,while under the condition of inhibition,the combustible was80.01 %,the concentrate ash was 7.88 %. The reason was that under the condition of inhibiton, the Zeta potential of kaolinite were significantly reduced with the increasing of the concentration of Ca2+, made it easier to cover the surface of coal particles compared with the inhibitition condition, the kaolinite Zeta potential was not obviously reduced under non-inhibiton condition.At the inhibition condition of TMBAC, the change of Montmorillonite and Kaolinite characteristics were little, Therefore, under the conditions of inhibiton and non-inhibition, the combustible recovery and concentrate ash also had a little difference.