Xinhua College of Ningxia University, Yinchuan, 750021, People's Republic of China.
State Key Laboratory of High-efficiency Coal Utilization and Green Chemical Engineering, Department of Chemistry & Chemical Engineering, Ningxia University, Yinchuan, 750021, People's Republic of China.
Environ Sci Pollut Res Int. 2021 May;28(17):21159-21173. doi: 10.1007/s11356-020-11962-y. Epub 2021 Jan 6.
Minimization and stabilization of arsenic-containing smelting wastewater and residue is of crucial issue to resolve the arsenic contamination. Calcium arsenate is a typical precipitate produced from disposal of smelting acid wastewater. However, it suffers from poor stability and large quantity in the aqueous environment. Copper slags, as for rich-iron species materials, are disposed of in landfills or open-air tailing ponds, which are another waste material that have not been effectively utilized for reuse application. In this study, strategy for sequence of phase-controlled and thermal-doped copper slag technique was used as the efficient means of minimization and stabilization of arsenic-bearing resides. Detailed results were showed that stepwise phase precipitation significantly reduced the formation of hazardous solid waste; the total solid waste was reduced 47.0 wt% because the gypsum was separated from arsenic calcium residues through two-step methods. Subsequently, solid waste stabilization was achieved by using thermal-doped slag, and the high yield of magnetite (75.6 wt%) and fayalite (22.7 wt%) was produced from copper slags. It was proved that these iron-rich species displayed the remarkable performance to stabilize arsenic due to the formation of Fe-As-Ca-O complex; compared with the raw solid waste, the arsenic leachability was decreased from 280.75 to 1.05 mg/L via copper slag stabilization process. The immobilized arsenic content was 25.0 wt%. Overall, the proposed strategy for stepwise phase-controlled and thermal-doped copper slags was a potentially effective strategy for reducing emissions and pollution of arsenic-containing wastewater and residue.
砷冶炼废水和废渣的减量化和稳定化是解决砷污染的关键问题。砷酸钙是一种典型的从冶炼酸废水中沉淀出来的产物。然而，它在水溶液中稳定性差，数量大。铜渣作为富铁物质材料，被堆放在垃圾填埋场或露天尾矿库中，这是另一种尚未得到有效利用的废物。在本研究中，采用分步相控和热掺杂铜渣技术的策略作为含砷渣减量化和稳定化的有效手段。详细结果表明，分步相沉淀显著减少了危险固体废物的形成；由于两步法将石膏从砷钙渣中分离出来，总固体废物减少了 47.0wt%。随后，通过热掺杂渣实现了固体废物的稳定化，从铜渣中得到了高产量的磁铁矿（75.6wt%）和铁橄榄石（22.7wt%）。事实证明，由于形成了 Fe-As-Ca-O 复合物，这些富铁物质表现出了稳定砷的显著性能；与原始固体废物相比，通过铜渣稳定化过程，砷浸出率从 280.75 降低到 1.05mg/L。固定砷含量为 25.0wt%。总的来说，分步相控和热掺杂铜渣的策略是一种减少含砷废水和废渣排放和污染的潜在有效策略。
