不同Fe^(3+)/Al^(3+)比复合阳离子絮凝剂聚合硫酸铝铁的合成及性能研究

Synthesis and Performance of Complex Poly-alumino-iron Sulfate Cationic Flocculant With Various Fe^(3+)/Al^(3+) Molar Ratio

为融合铁系与铝系絮凝剂的优点,以钢厂废渣或赤铁矿尾矿、粉煤灰和浓硫酸为原料,合成了不同Fe3+/Al3+比的复合阳离子型聚合硫酸铝铁(poly-alumino-iron sulfate,PAFS)絮凝剂。利用沸点升高法、络合滴定分析法(ethylene diaminetetraacethyl acid,EDTA)和红外光谱(infrared spectroscopy,IR)等方法对合成的PAFS进行了分析和表征,结果表明:PAFS的密度为1.45~1.64 g/mL,Fe3+含量>160 g/L,Al3+含量10.29~99.18 g/L,平均分子量为5.1×104;IR光谱显示PAFS是羟基桥联结构。利用四因素三水平L9(34)正交试验和混凝试验确定了制备PAFS的最佳条件。进行了自制PAFS与市售絮凝剂聚合氯化铝的絮凝效果对比试验,结果表明PAFS对黄河水的除浊率达到了100%,对COD的去除率达到40%,和工业产品聚合氯化铝相比,制备的PAFS具有除浊率高、投药量少、成本低的优点,显示出良好的工业应用前景。

In order to merge together merit of Fe and Al series cationic flocculant, poly-alumino-iron sulfate （PAFS） with different Fe3＋/Al3＋ molar ratio, were synthesized by using steel slag or hematite, concentrated sulfuric acid and fly ash as raw materials. The schemes of boiling-point elevation, EDTA titration, and IR spectroscopy were utilized to analyze and characterize the PAFS. The results show that the density of the PAFS is 1.45~1.64 g/mL. The content of Fe3＋ is more than 160 g/L, and the content of Al3＋ ranges from 10.29 to 99.18 g/L. The average molecular weight is 5.1′104. The results of the IR spectra indicated that the PAFS is hydroxyl-bridged structures. The best technique of preparing PAFS was ascertained by means of the orthogonal experiment of four elements and three levels and the coagulating test. The comparative experiment on flocculation effect of homemade PAFS and commercial polyaluminum chloride （PAC） was carried out. The results revealed that the efficiency of turbidity and COD removal from Yellow River achieved 100% and 40%, respectively. Compared with industrial polyaluminum chloride, the advantages of the prepared PAFS are high turbidity removal efficiency, less dosage, and low cost. The PAFS has a good prospect for industrial application.