酸洗废液制备聚硅酸复合氯化铁絮凝剂的研究

Research on the preparation of polysilicon acid ferric chloride flocculant from waste pickling liquor

以盐酸酸洗废液为原料,通过投加Na_2S沉淀废液中的Pb^(2+),加入硅酸钠发生聚合作用,制备聚硅酸复合氯化铁絮凝剂(PSFC)。研究Na_2S投加量和反应温度对Pb^(2+)去除效果的影响,并对Na_2S沉淀Pb^(2+)的反应动力学进行探究。利用单因素实验法分析不同制备温度、n(Fe)∶n(Si)、n(NaOH)∶n(Fe)对Fe3+聚合形态和PSFC絮凝效果的影响,通过正交试验优化制备条件。结果表明,Na_2S去除Pb^(2+)最佳条件为n(Na_2S)∶n(Pb^(2+))=3.0,Na_2S沉淀Pb^(2+)反应满足一级反应动力学模型。絮凝剂最佳制备条件:温度为25℃、n(Fe)∶n(Si)=25、n(NaOH)∶n(Fe)=0.5。

Polysilicon acid ferric chloride flocculant(PSFC)has been prepared by using waste pickling liquor(WPL)as raw material,adding the Na2S to precipitate Pb2+in waste liquor,and adding sodium silicate to bring about poly-merization.The influences of Na2S dosage and reaction temperature on Pb2+removing effect have been investigated.In addition,the reaction kinetics of Na2S precipitation of Pb2+has been probed into.The influences of different prepara-tion temperatures,n(Fe)∶n(Si)and n(NaOH)∶n(Fe)on Fe3+polymeric forms and PSFC flocculation effect have been analyzed by means single-factor tests,and the preparation conditions optimized by means of orthogonal tests.The re-sults show that the optimal conditions of the Pb2+removal by Na2S is n(Na2S)∶n(Pb2+)=3.0.The Na2S precipitation of Pb2+obeys the first order reaction model.The optimal preparation conditions of the flocculant are as follows:the tem-perature is 25℃,n(Fe)∶n(Si)=25,n(NaOH)∶n(Fe)=0.5.