科研之友
微信
新浪微博
Facebook
分享链接
摘要
The economical and effective removal of As and Pb from copper smelting slags was crucial to its harmless disposal, and the removal efficiency was limited by the fayalite structure. In this work, an eco-friendly strategy for effective removal of As and Pb from copper smelting slags was proposed based on NaOH/Na2CO3 alkali co-disaggregation coupled with acid leaching, the process parameters that affect metal leaching efficiency of alkali co-disaggregation and acid leaching process were systematically optimized, the environmental risks of the treated residues were evaluated, and the co-disaggregation mechanism of copper smelting slags by NaOH/Na2CO3 was studied through multiple characterization. Under optimal conditions of alkali co-disaggregation, 62.66% of As but almost no Pb was leached out. Then during the acid leaching, 33.57% of As and 96.55% of Pb were further leached out of copper smelting slags. Finally, the total leaching efficiency of As and Pb reached up to 96.23% and 96.55%, respectively. After treatment, the content of As and Pb in the copper smelting slags was drastically reduced from 1002.5 mg·kg-1 and 5343.1 mg·kg-1 to 112.1 mg·kg-1 and 170.2 mg·kg-1, respectively. Moreover, the leaching toxicity of the treated residues was below the standard limit. XRD, SEM-EDS mapping, FTIR results indicated that fayalite in copper smelting slags was decomposed, exposing the harmful ingredients which were converted into acid-soluble forms after alkali co-disaggregation to promote subsequent acid leaching efficiency. The existence of Na2CO3 expanded the disaggregation pathway of fayalite, and provided a new removal approach for As and Pb. This work inspired the harmless treatment of fayalite-containing slags. ? 2022, Science Press. All right reserved.
- 单位
