聚硅酸铁的制备及影响因素优化

Preparation of Poly-Silicic-Ferric Coagulant and Optimization of Influencing Factors

以水玻璃、硫酸亚铁及氯酸钠为原料，采用参数水平预筛选和混合水平渐进正交设计法制备聚硅酸铁（PSF）混凝剂，探讨制备过程影响因素并优化，对比分析PSF、聚合硫酸铁（PFS）和复合铝铁（PFA）的混凝效果。结果表明，PSF的制备过程是共聚合成工艺，其最佳合成条件为：氧化剂用量为0．845～0．951g，硫酸（c=98％）用量为2．8～3．2mL，反应温度为（30～50）℃，初始彬（SiO2）=（3．5～5．5）％，pH=3．5，聚合时间=1～2．5h，反应时间=1～2．5b。当PSF的最佳投药浓度=2．16×10^-5mol·L^-1，其在5min时基本沉淀完全，其混凝性能远优于PFS和PFA。

The preparation of poly-silicie-ferric （PSF） coagulant using water glass, ferrous sulfate and sodium chlorate was studied by level selection beforehand and mixing level and stepwise orthogonal design （LS-MLSO） , and the factors influencing preparation process were investigated and optimized. Coagulation behavior between PSF and raw materials, and between PSF and polyferric sulfate （PFS）, polyferric aluminum （PFA）, were studied, respectively. The results indicate that the optimal preparation conditions are as follows：the addition of NaCIO3 and H2SO4 （c =98% ） are 0. 845～0. 951 g and 2.8 -3.2 mL,reaction temperature is （30 ～ 50） ℃.,the initial mass concentration of w （ SiO2 ） is （ 3.5 - 5.5 ） % , polymerization pH and polymerization time of poly-silic acid are 3.5 and 1 ～ 2.5 h ,respectively, and reaction time of PSF is 1～2.5 h. PSF is found to be a complexation compound of Si,Fe and many other ions, instead of a simple mixture of raw materials. PSF is characterized by having higher coagulation efficiency than PFS and PFA, in which the optimal dose of PSF is 2.16 ×10^-5 mol· L-1 .and the settling time of PSF is 5 min or so.