Recycling And Comprehensive Utilization Of Metallurgical Waste With High Arsenic Content

Currently, there have a large number of high-arsenic content metallurgical wastes and the smelting dust occupies a large proportion. Beside of high content of As, the dust also has a considerable part of non-ferrous metals like Cu、Zn and other precious metals like Au、Ag et al. In view of the limitation of current technology in applicability、security、 environmental protection, developing an efficient、environmentally friendly、adaptable process will have a huge economic and social benefits.A research group of related fields of CSU, launched a systematic test that focus on the themes about "free from contamination、resource recovery、clean、short-stage". Based on a high-arsenic dust, a united technology that about arsenic removal was developed which consist of water leaching of hot pressing near the boiling point and gradient oxidative acid leaching. Combined with segmented extraction of Cu、Zn and disposal of arsenic waste water and the stabilization of its residue, high-purity As2O3、lead concentrate、compliance waste water、safe residue can be got finally.Free-stuff arsenic oxide which can reduce the burden of subsequent acid leaching firstly was lixiviated by water leaching that of hot pressing near the boiling point. The following operational variables and levels such as time, temperature and liquid-to-solid ratio were performed respectively in order to evaluate their effect on arsenic removal. High purity As2O3product with content of impurity element less than1%was prepared through concentrated crystallization process.Flooding slag was treated by gradient oxidative acide leaching for arsenic removal. The following operational variables and levels such as time、temperature、the concentration of H2SO4and the amount of H2O2were performed respectively in order to evaluate their effect on arsenic removal. After acid leaching, the content of As in lead concentrate reduced to1%while Pb increased to68.2%. The period acid leaching solution was carried out with the extractants N902to separate Cu and Zn. Then Zn was extracted by P204. Through a single factor experiments, the optimum extraction and stripping technical conditions were determined. The leaching efficiency of Cu and Zn are96.35%and96.38%, while the stripping efficiency are94.9%and99%.The arsenic-containing water was dealed by FS and PFS for arsenic removal. Under the potimum conditions that got through the single factor experiments, the arsenic content declined from6.4g/L to less than0.5mg/L which satisfy the discharge requirement after the initial removal of arsenic by FS. While after the water was further treated by PFS, the number reduced within0.05mg/L that meet the requirement of As content in drinking water.The entire leaching process not only ensure the thoroughness of arsenic removal, but also achieve the resource recovery of As. Combined with the disposal of wastewater and residue, the whole process can fulfill the purose to set the high arsenic metallurgy waste be harmless and the the resource recovery be clean. It also provides a new technical scheme to the industrial production.