Zinc-containing dust generated from the iron and steel industry is enriched with a large amount of heavy metal substances and rare elements, which is a hazardous waste and a secondary resource. In this study, a new process for the preparation of active zinc oxide and synergistic recovery of valuable elements using zinc-containing dust was proposed. Firstly, a fire process was used to make the valuable components such as Zn, Cd, K, Na, Pb, Bi, In and Sn secondary enriched in the zinc-rich dust. Then the leaching and recovery of K (99.74 %) and Na (98.12 %) were realized by alkaline washing method taking advantage of the solubility difference. Thermodynamic analysis showed that controlling the pH of the leaching system could realize the selective separation of the valuable components. The experimental results showed that the leaching rates of Zn and Cd reached 86.95 % and 92.28 %, respectively, under the optimal experimental conditions, while Pb, Sn, Bi and In were enriched in the neutral leaching slag. Cd sponge (70.3 %) was obtained after the neutral leach solution was treated by Zn powder replacement process. The purified zinc sulfate solution was used to prepare active zinc oxide (97.04 %) by direct precipitation at a molar ratio of CO32–/Zn2+ of 1.15 and a temperature of 50 °C. The average particle size of the product was 21.95 nm, which was in accordance with the industry standard. Neutral leaching slag realized Bi (91.5 %), Sn (71.01 %) and In (94.0 %) in high acid leaching process, and Pb was enriched in slag in the form of PbSO4. The high acid leach solution is hydrolyzed, extracted and replaced to obtain BiOCl, crude tin and crude indium. This process realizes the comprehensive recovery and high-value utilization of various valuable elements in zinc-containing dust sludge, and has significant environmental, economic and social benefits.
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