用赤铁矿制备聚硅酸铁絮凝剂及应用研究

Preparation of Polysilicate Ferrite Flocculant with Hematite and Its Application

采用酸浸—催化氧化—水解—聚合工艺,进行了以低品位赤铁矿、废硫酸和硅酸钠为原料制备聚硅酸铁(PSF)絮凝剂的试验研究,结果表明,适宜的工艺条件为硫酸浓度5～6 mol/L,液固比4:1,酸浸温度90℃,酸浸时间2-3 h,氧流量40cm^3/(min·L),Fe/Si摩尔比=2,硅酸活化pH值=3,硅酸活化时间25 min,陈化时间2 h。用所制备的PSF处理印染废水,并与聚合硫酸铁(PFS)和聚合氯化铝(PAC)进行比较,结果表明,在90 mg/L用量下,PSF可使废水中浊度、色度、SS和COD_(Cr)的去除率分别达到91.5%、87.8%、92.2%和78.5%,比相同用量下的PFS和PAC均分别高出10、24、14、18个百分点以上。

Test research was made on the preparation of polysilieate ferrite （PSF） flocculant by the process of acid leaching, catalytic oxidation, hydrolysis and polymerization with low grade hematite, spent sulfuric acid and sodium silicate. The results show that the optimal process conditions include ： sulfuric acid concentration of 5 - 6 mol/L ; liquid-solid ratio of 4：1 , acid leaching temperature of 90 ℃ , acid leaching time of 2 -3 h, oxygen flowrate of 40 cm^3/（ min · L） , Fe/ Si tool ratio of 2, pH value of 3 for activating silicate, silicate activating time of 25 min and aging time of 2 h. The resultant PSF was used in treating the waste water from printing and dyeing and was compared with polymerized ferric sulfate （PFS） and polyaluminium chloride （PAC）. The results show that at a dosage of 90 nag/L, PSF can remove the turbidity, chroma, SS and CODer from the waste water by 91.5% , 87.8% , 92.2% and 78.5% respectively, 10, 24, 14 and 18 percentage points higher respectively than those by PFS and PAC at the same dosage.