铝钙粉浸出渣的活化及其在锌冶炼废水处理中的应用

Activation of calcium aluminate leaching residues and their application in treatment of zinc metallurgical wastewater

以PAC生产过程中铝钙粉浸出渣为原料,采用盐酸和氢氧化钠进行活化,并对其在锌冶炼废水中吸附重金属的性能进行研究。考察铝钙粉浸出渣及其活化产物结构、比表面积、孔结构的变化,分析了pH值、吸附时间和重金属浓度对其吸附性能的影响,并以氢氧化钠活化产物为吸附剂进行了工业实验。结果表明:铝钙粉浸出渣经盐酸和氢氧化钠活化后,其结构均由岛状变为层状。铝钙粉浸出渣、盐酸活化产物和氢氧化钠活化产物的比表面积分别为21.8、63.1、28.1 m^2/g,BJH孔径分别为36.06、43.54和236.35 nm,孔容分别为0.03、0.09和0.14cm^3/g。pH=8,吸附温度为25℃,吸附时间为150 min时,由Langmuir方程得到铝钙粉浸出渣对Cd^2+、Zn^2+和As(V)的饱和吸附量分别为2.81、497.57和2.45 mg/g,盐酸活化产物对Cd^2+、Zn^2+和As(V)的饱和吸附量分别为3.44、516.32和2.04 mg/g,氢氧化钠活化产物对Cd^2+、Zn^2+和As(V)的饱和吸附量分别为7.64、526.32和4.72 mg/g。工业实验结果表明:吸附过程具有化学吸附特征,废水中Cu^2+、Pb^2+、Zn^2+、Cd^2+和As(V)的浓度由1.68、13.12、147.00、15.14和1.56 mg/L降至0.01、0.05、0.52、0.03和0.02 mg/L,达到《铅、锌污染物排放标准》(GB25466 2010)。

The calcium aluminate leaching residues(CALR),which were from the process of polyaluminum chloride production,were activated by hydrochloric acid and sodium hydroxide,respectively,and the adsorption properties CALR and activation products on heavy metals in zinc metallurgical wastewater were researched.The change of structure,specific surface area,pore structure of CALR and activation products were investigated.The effects of pH value,adsorption time and heavy metal concentration on its adsorption performance were analyzed.The industrial experiments were also conducted with NaOH activation products(NaOH AP).The results show that the structure changes from island to layer after CALR are activated by HCl and NaOH.The specific surface areas of CALR,HCl activation products(HCl AP)and NaOH AP are 21.8,63.1,28.1 m^2/g,respectively,the BJH pore diameters of CALR,HCl activation products(HCl AP)and NaOH AP are 36.06,43.54,236.35 nm,respectively,and the pore volumes of CALR,HCl activation products(HCl AP)and NaOH AP are 0.03,0.09,0.14 cm^3/g,respectively.According to Langmuir isotherm,the saturation Cd^2+,Zn^2+,As(V)adsorption capacities are 21.8,497.57,2.45 mg/g,respectively,the adsorption capacities of HCl AP are 3.44,516.32,2.04 mg/g,respectively,and the adsorption capacities of NaOH AP are 7.64,526.32,4.72 mg/g,respectively,when pH value is 8,the adsorption temperature is 25℃,adsorption time is 150 min.The industrial experiment results show that the chemical adsorption is in possession of adsorption process and that the concentrations of Cu^2+,Pb^2+,Zn^2+,Cd^2+,and As(V)in zinc metallurgical wastewater treated with NaOH AP decrease from 1.68,13.12,147.00,15.14,and 1.56 mg/L to 0.01,0.05,0.52,0.03,and 0.02 mg/L,respectively.The water qualities reach up to the“Emission Standard of Pollutants for Lead and Zinc Industry”(GB25466 2010).