The process of extracting zinc from refined zinc sulfide ore mainly includes the following steps

The process of extracting zinc from refined zinc sulfide ore mainly includes the following steps：

Roasting: Firstly, zinc sulfide concentrate undergoes roasting treatment with the aim of completely oxidizing metal sulfides as much as possible and obtaining oxides and a small amount of sulfates in the roasted sand. This step also involves partial sulfation roasting to compensate for the loss of sulfuric acid in the electrolysis and leaching circulation system. Meanwhile, through roasting, arsenic and antimony in the concentrate can be removed, oxidized, and removed from the concentrate in a volatile state. In addition, during roasting, it is necessary to obtain as little zinc ferrite as possible and obtain fine particle shaped roasted ore to facilitate the subsequent leaching process.

Leaching: The material after roasting is subjected to leaching treatment, which usually includes two stages: neutral leaching and acidic leaching. In the neutral leaching stage, electrolytic waste liquid is used to dissolve most of the zinc oxide under suitable temperature and pH conditions, obtaining the supernatant and bottom flow slurry. The bottom flow slurry is subjected to acid leaching to dissolve residual zinc oxide. The acidic leaching solution is returned to neutral leaching for recycling, while the acidic leaching residue containing about 20% zinc needs further treatment.

Solution purification: The supernatant obtained from leaching needs to be purified to remove impurities and improve the purity of zinc. The purified solution is prepared for the electro deposition of metallic zinc.

Electrodeposition produces metallic zinc: The purified solution produces metallic zinc through the electro deposition process, which involves electrolyzing the purified solution to reduce zinc ions to metallic zinc on the cathode, and then melting and casting it into ingots. This step is the key process 2 for extracting pure zinc.

Improvement of traditional methods: In order to improve the recovery rate of zinc and reduce the zinc content in iron slag, a method combining roasting leaching and direct leaching of zinc sulfide concentrate can be adopted. This method involves neutral leaching of zinc roasted sand from zinc sulfide concentrate, followed by hot acid leaching of the bottom stream. Finally, add zinc sulfide concentrate to the supernatant, introduce high concentration oxygen, control appropriate temperature and pressure conditions, and simultaneously leach zinc and remove iron. This method simplifies the process flow and improves the recovery rate of zinc by 3.

Through the above steps, metallic zinc can be effectively extracted from refined zinc sulfide ore.