Influence of controlled dispersion on rheology of swelling clay suspensions in the presence of coal flotation reagents

Swelling clay minerals, which are innately capable of dispersing into thin flakes in water, can significantly depress coal flotation. Some researchers partially attribute depression to pulp viscosity increments. This study sought to understand the role of swelling clay minerals in fine coal flotation, by investigating the rheological behavior of bentonite suspensions under controlled and uncontrolled dispersion conditions. The effect of collector, frother, and solution pH on rheological properties of the pulp was studied. Findings showed that at a natural pH, Newtonian flow properties were displayed when bentonite was directly added into a swelling suppressed solution containing calcium ions. The same process was repeated under uncontrolled conditions, and the suspensions transferred from Newtonian to non-Newtonian flows with pseudo-plastic characteristics, depending on the solid density. Further, pH value, methyl isobutyl carbinol (MIBC) and kerosene had the potential to alter the rheological behavior of controlled and uncontrolled systems, especially pH value in the uncontrolled system.