Effect of polyacrylamide conditioning combined with aluminum sulfate on Tongkeng mine slurry dewatering behavior

The influence of polyacrylamide (PAM) conditioning combined with Al₂(SO₄)₃ coagulant on Tongkeng mine slurry dewatering behavior was investigated by capillary water absorption time (CST) measurements. The depen-dence of the slurry dewatering behavior on interval time of adding chemicals, stirring time, stir intensity, total dosage of chemicals, and chemicals ratio were analyzed in detail. When adding PAM alone in the slurry, the CST reaches its minimum value of 17.4 s at the PAM dosage of 3 mg·g^-1. But when simultaneously adding Al₂(SO₄)₃ coagulant and 3 mg·g^-1 PAM in the slurry, the CST decreases to 16.9 s at the Al₂(SO₄)₃ dosage of 1.5 mg·g^-1. The appropriate opreating conditions were experimentally determined as the interval time of adding chemicals of 45 s, the stirring time of 120 s, and the stirring intensity of 40 r·min^-1. By means of orthogonal experiment design, the significance of parameters influencing the slurry dewatering behavior is in the order of total dosage of chemicals 〉 chemicals ratios, and the optimal total dosage of chemicals is 4 mg·g^-1, with the mass ratio of PAM and Al₂(SO₄)₃ of 1:3.