Separation and stabilization of arsenic in copper smelting wastewater by zinc slag. (20th August 2021)

• Record Type: Journal Article
• Authors: Duan, Xiaoxu; Li, Xuezhu; Li, Yongkui; Qi, Xianjin; Li, Guohua; Lu, Zhixu; Yang, Nina
• Is Part Of: Journal of cleaner production. Volume 312(2021)
• Publication Date: 2021-08-20
• Subjects: Arsenic removal -- Copper smelting wastewater -- Zinc slag -- Iron arsenate -- Silicone encapsulation; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2021.127797
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Copper smelting wastewater shows strong acidity, has a high arsenic concentration and has many types of heavy metals, which not only restricts the sustainable development of copper smelting enterprises but also poses a danger to the ecological environment. Here, we propose a new process for treating copper smelting wastewater with zinc slag. We studied both the solid-liquid chemical reaction process as well as the mechanism by which zinc slag removes arsenic in copper smelting wastewater in a water bath at 85 °C under atmospheric pressure. Specifically, 5 g of zinc slag reacted with copper smelting wastewater with an initial arsenic concentration of 6000 mg/L for 4 h resulted in an arsenic removal rate of 99.65%, and the leaching concentration of arsenic in the toxicity characteristic leaching procedure experiment was only 0.52 mg/L. Zinc slag is dissolved in Copper smelting wastewater to release iron ions and silicate. The solid-liquid reaction of the two is accompanied by coprecipitation of iron arsenate and the in-situ covering of silica gel, resulting in a core-shell precipitate with iron arsenate as the core and silica gel as the shell. The colloidal chemistry of silica gel and cations and its chemical stability can effectively prevent the dissolution of arsenic ions and significantly improve the stability of iron arsenate. Zinc slag, a dual functional material for removing arsenic and fixing arsenic, shows extraordinary potential for the removal and fixation of arsenic in copper smelting wastewater. This approach could further improve wastewater treatment in the non-ferrous smelting industry. Graphical abstract: Image 1 Highlights: Core-shell precipitate with silica gel as the shell and ferric arsenate as the core. Zinc slag exhibited excellent arsenic removal and arsenic fixation ability. The arsenic removal rate reaches 99.65%. The toxic leaching As concentration is almost undetectable.