中文摘要：

采用参数水平的预先筛选及混合水平渐进正交实验设计法制备聚硅酸铁（PSF）混凝剂，应用2种不同方案（方案A、方案B）制备不同si与Fe摩尔比（以n表示）的PSF，并对2种方案制备的PSF的物化性征、微观形态及混凝效能进行对比研究．结果表明，混合水平渐进正交实验法是研制高效混凝剂有效、合理的方法，2种方案制备的PSF物化性征和微观形态差别很大，方案B制备的各种n的PSF具有相近的物化性质，混凝效果明显优于方案A制备的PSF．

英文摘要：

The preparation of poly-silicic ferric （PSF） coagulant was studied by level selection beforehand and mixing level and stepwise orthogonal design （LS-MLSO） , in which different Si/Fe molar ratios of PSF were prepared by two different methods （method A and method B ）, respectively. The physicoehemical characteristics, micro properties and coagulation efficiency of PSF prepared by method A were studied, in comparison with those of PSF prepared by method B. The results show that LS-MLSO is an efficient and reasonable method in the investigation of coagulant preparation. The physicochemical characteristics and micro properties of PSF prepared by method A was significantly different from those of PSF prepared by method B, in which various Si/Fe ratios of PSF prepared by method B have similar physicochemical characteristics and micro properties. PSF prepared by method A were characterized obviously by having higher coagulation behavior than PSF prepared by method A.