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Copper, Zinc, and Lead Recovery from Jarosite Pb–Ag Tailings Waste (Part 2)
oleh: Vesna Conić, Miloš Janošević, Dragana S. Božić, Ljiljana Avramović, Ivana Jovanović, Dejan M. Bugarin, Stefan Đorđievski
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2024-07-01 |
Deskripsi
The present paper describes the technological solution for obtaining Cu, Zn, Pb, and Ag from jarosite waste raw material, with its simultaneous separation from In and Fe. By roasting at low temperatures, iron was transformed from the Fe<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> form into Fe<sub>2</sub>O<sub>3</sub>, which is insoluble in water and slightly soluble in acid. Copper sulfate and zinc sulfate are present in jarosite as sulfates. During temperature roasting, the copper and zinc were still in the form of CuSO<sub>4</sub> and ZnSO<sub>4</sub>, i.e., they were easily dissolved in water. This procedure led to good selectivity of Cu and Zn compared to Fe. After water leaching, PbSO<sub>4</sub> and Ag<sub>2</sub>SO<sub>4</sub> remained in the solid residue. By treating jarosite with a content of 0.7% Cu, 5.39% Zn, and 5.68% Pb, products of commercial quality were obtained. By roasting jarosite in an electric furnace and leaching the roasted sample in water, leaching degrees of 91.07%, 91.97%, and 9.60% were obtained for Cu, Zn, and Fe, respectively. Using 1 M NaOH in the leaching solution, 99.93% Fe was precipitated to pH = 4. Cu in the form of CuSO<sub>4</sub> was further treated by cementation with Zn, after which cement copper was obtained as a commercial product. Zn in the form of ZnSO<sub>4</sub> was further treated by precipitation with Na<sub>2</sub>CO<sub>3</sub> to obtain ZnCO<sub>3</sub> concentrate of commercial grade. The total recovery of Pb and Ag, which were treated by chloride leaching, was 96.05% and 87.5%, respectively. The resulting NaPbCl<sub>3</sub> solution was further treated with Na<sub>2</sub>CO<sub>3</sub> solution, whereby PbCO<sub>3</sub> was obtained as a commercial product. The produced PbCO<sub>3</sub> could be further subjected to roasting to obtain soluble PbO. In these investigations, PbCO<sub>3</sub> was smelted where a Pb anode was obtained; this was electrolytically refined to a Pb cathode. The proposed process does not pollute the environment with As and Cd.