赤泥制备聚合硫酸铝铁及其处理废水的研究

Study on Synthesis of PAFS Based on Red Mud and ItsApplication in Wastewater Treatment

本工作以拜尔法赤泥为原料,采用硫酸浸取的方法浸出铝和铁,通过加入碱化剂聚合制备出高效无机高分子絮凝剂聚合硫酸铝铁(PAFS),研究了反应条件对酸浸过程及PAFS处理模拟废水性能的影响。实验结果表明:在焙烧温度为900℃,硫酸体积浓度为45%,硫酸与拜耳法赤泥的液固比为9 mL/g,酸溶温度为100℃,反应时间为1 h的条件下,拜耳法赤泥中Al2O3的溶出率为93.01%,Fe2O3的溶出率为89.54%。在模拟废水的浊度去除率实验中,PAFS和PAC的投加量、废水浓度、pH值、温度等对废水浊度去除率均有明显的效果,且自制的PAFS净化性能优于工业级的PAC,其中PAC的最高去浊率为90%,而PAFS的最高去浊率达96%以上。

Red mud is a valuable and abundant secondary mineral resource.In this study,aluminum and iron are leached by sulfuric acid leaching method from Bayer red mud as raw material,and high-efficiency inorganic polymer flocculation was prepared by adding alkalizing agent.Polymeric aluminum ferric sulfate(PAFS)was polymerized and the effects of reaction conditions on the acid leaching process and PAFS treatment of kaolin wastewater were studied by single factor experiments,and compared with the effect of industrial grade polyaluminum chloride(PAC).The experimental results show that the calcination temperature of red mud is 900℃,the volume concentration of sulfuric acid is 45%,the mass ratio of solid solution of sulfuric acid to Bayer red mud is 9 mL/g,the acid solution temperature is 100℃,and the reaction time is 1 h.Under the optimized conditions,the dissolution rate of Al 2O 3 in Bayer red mud is 93.01%,and the dissolution rate of Fe 2O 3 is 89.54%.In the experiment on the effect of turbidity removal rate of kaolin wastewater,the dosage of PAFS and PAC,the concentration of kaolin wastewater,the pH value of wastewater,and the temperature have obvious effects on the turbidity removal rate of wastewater,and the purified water of PAFS is self-made.The performance of PAFS is superior to that of industrial grade PAC.The highest turbidity rate of PAC is 90%,while the highest turbidity rate of PAFS is over 96%.