搅拌槽内絮凝动力学研究

Study of Flocculation Kinetics in a Stirred Tank

采用激光粒度仪在线测定并研究了搅拌槽内聚丙烯酰胺与磷矿酸解渣的絮凝动力学; 考察了不同浓度的酸解液、絮凝剂加入量、温度、酸解渣原始平均粒径和搅拌强度对絮凝动力学影响。在实验研究范围,絮凝初始速度随温度升高、絮凝剂加入量及搅拌强度的增加而提高,但随着酸解液的粘度增加和酸解渣原始平均粒径的增大而降低,体系中存在最佳的絮凝剂加入量。通过酸解渣的电泳试验,用自合成的阴离子、阳离子改性絮凝剂以及非离子型絮凝剂与酸解渣的絮凝试验发现,在中性的水中, 酸解渣与不同荷电类型的絮凝剂的絮凝速度大小依次为: 阳离子型>非离子型>阴离子型。而在磷酸酸解料浆中絮凝速度与絮凝剂的荷电类型无关。磷矿酸解渣与聚丙烯酰胺絮凝剂的作用主要表现为架桥机理。

A laser particle size analyzer was used to study kinetics of the flocculation of fine phosphate ore residues in presence of polyacrylamide (PAM) flocculent in a stirred tank. It was found that the initial flocculation rate was enhanced by increasing temperature, agitation speed and PAM dosage separately, but decreased with the increase of the viscosity of fluid and primary residue average sizes. There was an optimal PAM dosage associating with solids' concentration. The kind of electric-charge on residue surface was detected by electrophoresis. Flocculation of residue with different kinds of electric-charge carrying flocculents showed that the flocculation rate order is: cationic PAM > non-ionic PAM > anionic PAM in water, but no differences in the leaching solution. The flocculation of fine phosphate ore residues with PAM follows the bridging mechanism.