Effect of mixing conditions on flocculation

Abstract

In this work, effects of mixing conditions (mixing time and speed) on flocculation performance of fine coal particles (-0.180 mm) bearing inorganic materials (kaolinite, illite, quartz and muscovite) in the presence of medium and low charged anionic polymers were investigated. The flocculation test results in the presence of medium (Praestol 2540) and low charge (Praestol 2515) density anionic flocculants with high molecular weight at natural pH (8.3) were compared. Praestol 2540, medium anionic polymer, achieved effective results more than low anionic. The optimum mixing time (30 seconds) was reached at settling rates at 100 mm/min with the lowest turbidity value of 12.5 NTU and the optimum mixing speed (150 rpm) obtained at 18.5 NTU. And also, the characterization of coal tailings was made with the help of mineralogical data and instrumental analysis techniques. The zeta potential value of ultra fine coal tailings was -29mV at natural pH of 8.3.