CaO-PAM在鲕状赤铁矿浮选废水处理中的混凝作用

Flocculation of CaO-PAM in Flotation Wastewater Treatment of Oolitic Hematite

鄂西高磷鲕状赤铁矿采用细磨-反浮选工艺可有效提铁降杂,实现铁的回收利用。但该工艺产生的废水浊度高,成分复杂,浮选废水回用困难。本研究对该反浮选废水进行了研究,发现废水pH值为9.6,散射浊度为95780 NTU,悬浮物浓度为1272 mg/L。采用氧化钙(CaO)与聚丙烯酰胺(PAM)联用混凝沉淀法处理该废水,用量分别为350 mg/L和20 mg/L时,搅拌速率80 r/min搅拌10 min,处理后废水浊度降至19.9 NTU,出水率为80%~90%。通过Zeta电位和扫描电镜研究发现,CaO-PAM的加入,降低了悬浮微细粒间的静电斥力,发生了双电层吸附,通过架桥作用使微细粒发生了絮凝沉淀,从而降低了废水浊度及金属离子含量,满足了废水循环使用的要求,降低了废水外排造成的资源浪费和环境污染危害。

It is effective to enrich iron and reduce impurity for high phosphorus oolitic hematite in western Hubei through the process to fine grinding-reverse flotation,which can realize the recovery and utilization of iron.However,the turbidity of wastewater produced by this process was high and its compositions were complex,which makes it difficult to recycle the flotation wastewater.In this paper,the reverse flotation wastewater was studied,and the results showed that the pH value of the wastewater was 9.6,the scattering turbidity was 95780 NTU,and the suspended matter concentration was 1272 mg/L.The method of Calcium oxide(CaO)and polyacrylamide(PAM)combined coagulation precipitation was performed to treat the flotation waste water..The treated wastewater with the turbidity of 19.9 NTU and the effluent rate from 80%to 90%can be obtained when the stirring time is 10 min with the stirring rate of 80 r/min,and the the dosage of CaO and PAM are 350 mg/L and 20 mg/L,respectively.It can be found from the Zeta potential and scanning electron microscopy that the addition of CaO-PAM can reduce the electrostatic repulsion between the suspended fine particles,which leads to the double electric layer adsorption.The fine particles are flocculated and precipitated by the bridging,which reduces the turbidity and metal ion content of waste water.It meets the requirements of recycling wastewater and reduces resource waste and environmental pollution hazards caused by wastewater discharge.