黄磷炉渣和粉煤灰合成聚硅酸盐及其絮凝性能的基础性研究

Polysilicate flocculant is a inorganic polymer flocculant with synergies effect, which is synthesized by recombination or copolymerization of two or more metal ions and polysilicic acid. The flocculant is a new type of water treatment agent developed on the basis of the traditional aluminum salt and iron salt flocculant. Compared with traditional inorganic flocculants, it has better coagulation property and is inexpensive, safe and nontoxic.The yellow phosphorus slag and flyash are a solid waste producse in the course of producing yellow phosphorus in electrical furnace and thermal power generation respectively, they contains a lot of CaO, SiO2 and Fe, Al, Mg respectively, and may be applied to producing Ca, Si and Fe, Al product.The project study synthesis of polysilicate inorganic polymer flocculant with yellow phosphorus slag and flyash as raw material, effect law of structural characteristics of yellow phosphorus slag and components on polysilicic acid morphology, structure characteristics and adsorption performance, decomposition, polymerization and activation reaction rule of synthesizeing polysilicic acid with yellow phosphorus slag. On the basis of adding metal cation with flyash, to study the key factors of influencing stability of polysilicate polymer flocculant, regulation and control rules of coagulation property of metal cation on polysilicate polymer flocculant, coagulation property and dynamics and mechanism of treating typical wastewater with polysilicate polymer flocculant and so on. The polysilicate polymer flocculant with excellent coagulation property and of containing a variety of metal ion can be obtained, and can be used for treatment field of polluted water or waste water.

聚硅酸盐絮凝剂是利用协同增效原理将两种或两种以上金属离子与活化硅酸通过复合的方法合成的无机高分子絮凝剂。该絮凝剂是在传统铝盐、铁盐絮凝剂基础上发展起来的一类新型水处理剂,与传统无机絮凝剂相比絮凝效果成倍提高且价格低廉、安全无毒。黄磷炉渣和粉煤灰分别是工业黄磷生产和火力发电过程中产生的固体废渣，主要成分分别为硅钙和铁铝镁等元素，可用于制取价值较高的硅钙和铁铝等产品。本项目以黄磷炉渣为硅源、粉煤灰为金属阳离子源，合成聚硅酸盐无机高分子絮凝剂，研究黄磷炉渣结构特性和组分影响聚硅酸形貌、结构特性及吸附性能的规律，黄磷炉渣合成聚硅酸过程的分解、聚合、活化反应规律，通过粉煤灰引入金属阳离子，研究影响聚硅酸盐稳定性的关键因素、对聚硅酸盐高分子絮凝剂混凝性能的调控规律，聚硅酸盐絮凝剂处理典型废水的混凝性能及聚硅酸盐絮凝剂絮凝动力学和机理等，可望获得多种金属离子复合、絮凝性能优良的聚硅酸盐。

黄磷炉渣是工业黄磷生产过程中产生的固体废渣，主要成分为硅钙，通过分离可制备价值较高的硅钙产品；粉煤灰为火力发电过程产生的固体废渣，主要含有铁、铝、镁等元素，可作为二次资源综合利用。本项目以黄磷炉渣为硅源、粉煤灰为金属阳离子源，采用硝酸溶液分解浸出，经聚合、活化和复合或接枝阳离子金属源，可得到多种金属离子复合、絮凝性能优良的聚硅酸盐絮凝剂。. 研究表明，硝酸溶液分解黄磷炉渣制备聚硅酸的优化工艺条件为：硝酸质量浓度为14%，液固质量比9:1，分解时间20min，分解温度20℃，搅拌速度为400rpm；聚合温度50℃，活化温度25℃，活化时间50min。聚硅酸经XRD、扫描电镜等分析表明，聚硅酸为无定型非晶体结构的颗粒状固体，体积平均粒径为79.81um；比表面积为601.23m2/g，比孔容0.42m3/g，平均孔径2.82nm。. 粉煤灰活化焙烧-硝酸溶液浸取的优化工艺条件为：焙烧过程碳酸氢钠与粉煤灰的质量比为0.7:1，活化温度800℃，活化时间45min；浸出过程硝酸浓度25%（质量分数），液固质量比10g/g，浸取温度80℃，浸取时间1.5h，搅拌速率380r/min；在此条件下铝、铁的浸出率分别为93.93%、90.55%。. 粉煤灰浸出液与聚硅酸复合制备聚硅酸盐高分子絮凝剂,粉煤灰浸出液调控聚硅酸盐絮凝性能的优化条件为：固液质量比为3:1、聚合时间30min、聚合温度55℃、搅拌速度300r/min、陈化温度40℃、陈化时间2h。优化工艺条件下，制备的聚硅酸盐絮凝剂对滇池污水浊度、COD和色度去除率分别可达到98.21%、84.77%、85.71%。. 聚硅酸盐絮凝剂用于处理滇池污水，具有良好的处理效果,其优化工艺条件为：絮凝剂加入量40mg/L、滇池污水的pH为6、絮凝温度55℃、沉降时间70min、沉降温度40℃；在此优化条件下，滇池污水浊度、COD和色度的去除率分别为99.70%、91.40%和92.57%。. 絮凝动力学研究表明：可采用体系粒子絮凝或凝聚时单位体积总的粒子数（N）随时间（t）的变化来描述聚硅酸盐絮凝剂处理滇池污水的动力学过程，絮凝初期絮团平均粒径与时间关系满足: ln(N/N0)＝-kt；采用双曲线模型能够更好描述聚硅酸盐絮凝剂处理滇池污水的沉降动力学过程。