Experimental Study On The Removal Of Lead And Zinc From Mine Wastewater By Modified Steel Slag

The amount of waste water discharged from mining and beneficiation in China is up to 1.2～1.5 billion tons per year.The lead and zinc ions in the mine waste water are toxic and non degradable.If discharged,it will harm hμman health and destroy the ecological environment.If circulating water is used,it will increase the difficulty of beneficiation and seriously affect the beneficiation index.Therefore,it is necessary to study the removal of lead and zinc ions in the mine waste water.Taking steel slag as experimental material,the best modification methods of absorbing lead and zinc ions were studied by single ion static adsorption method.The results showed that sulfuric acid with a concentration of 2mol/L was the best modification method in the experiment of absorbing lead ions;high temperature of 700℃ was the best modification method in the experiment of absorbing zinc ions;Under the best experimental conditions,the removal rate of lead ion can reach 97.10%;the removal rate of zinc ion can reach 96.46%;compared with the unmodified steel slag,the removal rate of lead and zinc ion can be increased by about 20%.The adsorption isotherm and kinetics were used to study the mechanism of the adsorption of lead and zinc ions by the modified steel slag.The results showed that the adsorption process of lead and zinc ions by the modified steel slag was well matched with the Langmuir model and the second-order kinetics model.The adsorption mode was single molecular layer adsorption,and the adsorption process involved the transfer and sharing of electrons.The chemical adsorption mechanism controlled the adsorption reaction rate.The results show that the removal rate of the mixed ions of lead and zinc is less than that of single ion,and the removal rate of zinc is greater than that of lead,which indicates that there is competitive adsorption between lead and zinc ions.The above research shows that the modified steel slag has a good adsorption effect on lead and zinc ions,can realize the purpose of "treating waste with waste",can achieve "waste treatment",and can provide data and theoretical support for the practical application of the modified steel slag in the treatment of heavy metal pollution in mine wastewater.Figure44;Table14;Reference 71...