氢氧化镁在聚丙烯酰胺体系中的聚沉行为

考察了难沉降的氢氧化镁微粒在高聚合度(分子量1500万)阴离子型聚丙烯酰胺体系中的聚沉行为. 通过分析氢氧化镁悬浮体系在聚沉过程中的沉降体积、团聚粒度分布、表面电位及特征官能团等参数的变化规律，初步探讨了聚丙烯酰胺的聚沉机制. 研究结果表明，聚丙烯酰胺通过吸附架桥和电荷中和两种方式加速氢氧化镁的聚沉速率，且对后继水热产物形貌无明显影响，是一种较为理想的絮凝剂. 在0 125 10 6浓度范围内，聚丙烯酰胺浓度越高，团聚体粒径越大，聚沉效果越显著.

Agglomeration and Precipitation of Mg(OH)2 Particles in the Presence of Polyacrylamide

The agglomeration and precipitation behaviors of Mg(OH)2 particles in the presence of anionic polyacrylamide with a molecular weight of 15 million were studied. The change of properties of the Mg(OH)2 suspensions such as precipitation volume, distribution of cluster size, z-potential and functional groups was investigated to reveal the role of polyacrylamide in the precipitation and agglomeration process of Mg(OH)2 particles. Experimental results indicate that the presence of anionic polyacrylamide can accelerate the agglomeration and precipitation of Mg(OH)2 particles via absorption-bridging and electric neutralization routes, and has little influence on the morphology of the hydrothermal products. In the range of 0~12510-6 anionic polyacrylamide, the increase of concentration of anionic polyacrylamide is favorable for the formation of Mg(OH)2 clusters with bigger sizes, leading to the acceleration of agglomeration and precipitation of Mg(OH)2 clusters.