Formation, breakage, and re-growth of quartz flocs generated by non-ionic high molecular weight polyacrylamide

Flotation of fine mineral particles is one of the major challenges faced by the minerals industries worldwide. Flocculation of these fine particles prior to flotation, to form separate hydrophobic and hydrophilic flocs, is one of the methods to tackle this challenge. In order to gain a better understanding of the properties of hydrophilic polymer flocs for the intended flocculation flotation, this paper reports testwork completed on the formation, breakage, and re-growth of quartz flocs when non-ionic high molecular weight polyacrylamide (PAM) was used as a flocculant under different test conditions in an alkaline environment. Focused beam reflectance measurement (FBRM) particle size analyses, coupled with sedimentation tests and optical microscope observations were performed to monitor the real-time evolution and change of quartz flocs. In addition, adsorption experiments and zeta potential measurements were carried out and used as parameters in the DLVO theory interaction energy estimation. The results of DLVO theory interaction energy estimation, settling experiments and optical microscope observations showed that the quartz particles dispersed well in slurry at pH 9. PAM had a strong flocculation ability to quartz particles, the peak values of floc size were affected by both the stirring rate and PAM concentration. In addition, the degree of floc breakage depended on the increased stirring rate and the shear time. Floc re-growth occurred to different extents according to the breakage durations and PAM dosages.