弱酸改性粉煤灰空心微珠用于处理铅锌选矿废水吸附试验研究

Weak Acid Treatment of Coal Fly Ash Cenospheres and the Adsorptive Removal of Impurities in Wastewaters of A Beneficiation Plant of Lead-zinc Sulphide Ores

提出将粉煤灰空心微珠作为吸附剂应用于铅锌选矿废水治理。首先采用BET、SEM、XRD、Zeta电位等测试方法,考察了微珠的弱酸活化机制,然后对实际废水中残留的选矿药剂以及重金属离子开展了吸附试验研究。结果表明:微珠经弱酸活化后,其表面电位由-1.797 6mV增加到-15.538 7mV,大幅度提高了静电吸附能力;对实际废水中的COD有很好的去除效果,但四种药剂呈现不同的吸附行为。饱和吸附量方面:腐植酸钠(6.492mg/g)>乙硫氮(2.250mg/g)>丁基黄药(1.680mg/g)>BK-906(0.024mg/g);吸附速率方面:腐植酸钠(K=0.330 2min^-1)>丁基黄药(K=0.312 1min^-1)>BK-906(K=0.020 1min^-1)>乙硫氮(K=0.008 1min^-1)。对废水中低浓度的Zn^2+、Pb^2+、Cu^2+离子也呈现出一定的去除效果,重金属离子与残留的选矿药剂的络合共吸附是其主要去除机理。

In this paper,cenospheres of coal fly ash were treated with weak sulphuric acid and then used in the adsorption of impurities in beneficiation wastewaters in a Pb-Zn sulphide ore plant.Firstly,the surface activation mechansm of coal fly ash cenospheres was investigated by BET,SEM,XRD,and Zeta potential.Then the adsorption experiments of flotation reagents and heavy metal ions in the beneficiation wastewaters were carried out.The results showed that the surface of cenospheres were effectively activated after the weak acid treatment with the surface potentials increase from-1.797 6 mV to-15.538 7 mV,which greatly enhanced the electrostatic adherence capacity of cenospheres.The good effect of removal rate for COD in actual wastewater was achieved,thermodynamics and kinetics results revealed different adsorption behaviors of four flotation reagents that have been used in the flotation circuit of the Pb-Zn sulphide ore.For the saturated adsorption capacities:humic acid sodium(6.492mg/g)>Ethyl thio carbamate(2.250 mg/g)>butyl xanthate(1.680 mg/g)>BK-906(0.024 mg/g).And for the adsorption rates:humic acid sodium(K=0.330 2min^-1)>butyl xanthate(K=0.312 1min^-1)>BK-906(K=0.020 1 min-1)>Ethyl thio carbamate(K=0.008 1 min^-1).The low concentration of Zn^2+,Pb^2+,Cu^2+in the wastewater also showed removal effects.The main adsorption mechanism is the co-adsorption of heavy metal ions with residual flotation reagents.