Chen Pan, Zhao Yuxin, Yao Jun, Zhu Jianyu, Cao Jian
School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-Containing Mineral Resources, Central South University, Changsha 410083, China.
Materials (Basel). 2022 Oct 25;15(21):7471. doi: 10.3390/ma15217471.
In situ treatment of acidic arsenic-containing wastewater from the non-ferrous metal smelting industry has been a great challenge for cleaner production in smelters. Scorodite and iron arsenate have been proved to be good arsenic-fixing minerals; thus, we used lead slag as an iron source to remove arsenic from wastewater by forming iron arsenate and scorodite. As the main contaminant in wastewater, As(III) was oxidized to As(V) by HO, which was further mineralized to low-crystalline iron arsenate by Fe(III) and Fe(II) released by lead slag (in situ generated). The calcium ions released from the dissolved lead slag combined with sulfate to form well-crystallized gypsum, which co-precipitated with iron arsenate and provided attachment sites for iron arsenate. In addition, a silicate colloid was generated from dissolved silicate minerals wrapped around the As-bearing precipitate particles, which reduced the arsenic-leaching toxicity. A 99.95% removal efficiency of arsenic with initial concentration of 6500 mg/L was reached when the solid-liquid ratio was 1:10 and after 12 h of reaction at room temperature. Moreover, the leaching toxicity of As-bearing precipitate was 3.36 mg/L (As) and 2.93 mg/L (Pb), lower than the leaching threshold (5 mg/L). This work can promote the joint treatment of slag and wastewater in smelters, which is conducive to the long-term development of resource utilization and clean production.
有色金属冶炼行业含砷酸性废水的原位处理一直是冶炼厂清洁生产面临的巨大挑战。臭葱石和砷酸铁已被证明是良好的固砷矿物；因此，我们使用铅渣作为铁源，通过形成砷酸铁和臭葱石来去除废水中的砷。作为废水中的主要污染物，As(III) 被 HO 氧化为 As(V)，As(V) 被铅渣（原位生成）释放的 Fe(III) 和 Fe(II) 进一步矿化为低结晶度的砷酸铁。溶解的铅渣释放出的钙离子与硫酸根结合形成结晶良好的石膏，石膏与砷酸铁共沉淀并为砷酸铁提供附着位点。此外，溶解的硅酸盐矿物产生的硅酸盐胶体包裹在含砷沉淀颗粒周围，降低了砷的浸出毒性。当固液比为 1:10 且在室温下反应 12 小时后，初始浓度为 6500 mg/L 的砷去除效率达到 99.95%。此外，含砷沉淀的浸出毒性为 3.36 mg/L（As）和 2.93 mg/L（Pb），低于浸出阈值（5 mg/L）。这项工作可以促进冶炼厂废渣与废水的联合处理，有利于资源利用和清洁生产的长远发展。
