磷矿酸解料浆与高分子絮凝剂形成的絮团特性研究

摘要

The structure and strength of floc formed by fine phosphate oreresidues with polyacrylamide in leaching solution of a developing phosphate acid producting process were investigeted. Video photograph was used to determine the floc density distributions by direct measuring the individual floc size and settling velocity. The measurements were carried out on well-characterized phosphate ore residue types flocculated under a variety of conditions. The result shows that the floc has a fractal property in experiments. The floc density is a function of its fractal dimension and its size. A typical fractal dimension of the floc is from 2.1 to 2.4. When the floc dimension is the same, the density decreases with increasing temperature and flocculent dosage, and with decreasing average primary particle size of flocs. The experimental measurement of floc strength was done under conditions of varying agitation rate, polymer molecular weight, flocculent dosage and average primary particle size. The break-up of flocs in the inertial subrange and viscous subrange were found to be consistent with the fragmentation for larger flocs, and the viscous erosion effect was dominant for the smallest turbulent subrange.%用光学连续摄像技术研究了不同絮凝条件下磷矿酸解渣与聚丙烯酰胺形成的絮团特性。实验结果表明酸解料浆与聚丙烯酰胺絮凝剂形成的絮团具有分形几何特征。应用分形理论得到絮团降落速度与絮团孔隙度和絮团密度的关系式。用激光粒度分布仪在线测定了流体力学条件对该体系絮团强度的影响，在湍流情况下絮团最大平均粒径取决于酸解渣原始平均粒径和体系的能量耗散。较大的絮团破坏主要以裂解为主，在最小的湍流漩涡区也存在相当程度的剥离破坏。试验发现絮团强度随聚合物分子量的增加而提高，对于获得最大平均粒径的稳定絮团存在最佳的絮凝剂加入量。