Wet-method process for reclaiming zinc from zinc leaching residue

Abstract

This invention relates to wet process of recovering zinc from leach slag containing zinc. It belongs to a wet process for zinc ore, in particular to a process for slag containing zinc produced from the systerm of wet zinc metallurgy. This method comprises the following steps: washing residue with water or diluted acid to get slag, selecting P204 as extractant and coal oil as thinner to extract them to water phase, configuring the solution containing zinc and sulfuric acid, eluting the impurity loaded in organic phase, back extracting the load organic phase with depleted electrolyte and sulfuric acid, transferring zinc in organic phase to water phase, deoiling all water phases which contact with organic phase, finally, taking the liquid which has been back extracted as fresh liquid, and adding it into zinc electrodeposition systerm. The invention has high metal recovery ratio, and can recovery zinc from leach slag containing zinc, save resource, avoid environmental contamination. And it perfectly joins with the process of wet processing of zinc oxide ore, decreases the consumption of acid in the leaching of zinc oxide, and reduces the cost.

Description

technical field [0001] The invention belongs to a zinc ore wet treatment process, in particular to a process for further recovering zinc from zinc-containing slag produced in a wet zinc smelting system. Background technique [0002] Zinc oxide ore is an important zinc-containing mineral resource. However, this kind of ore has a complex structure, a large amount of friable mud, low sorting index, many chemicals, and high cost. It is still a difficult problem in ore dressing. In the past, most rich ore was directly smelted. There are few enterprises dealing with zinc oxide ore in foreign countries, and the directly processed zinc oxide ore usually contains more than 35% zinc. Thailand's Badarien Zinc Smelter directly processes zinc oxide ore containing Zn>35%, and Iran processes zinc oxide ore containing about 40% Zn. [0003] Over the years, a lot of research has been done on the treatment of zinc oxide ore at home and abroad, including sulfuric acid method, sulfurous aci...

AI Technical Summary

Problems solved by technology

After the zinc leaching slag is filtered, the leach solution, which is generally more than 30% of the dry slag, is usually entrained in the filter residue, and the zinc concentration of this part of the solution is high, generally above 100g / L, so the slag entrains a considerable amount of zinc, which reduces the metal content. The recovery rate is high, causing metal loss and also polluting the environment

[0007] The zinc entrained in the slag is mainly water-soluble zinc. Although it can be washed out with water (or dilute acid), the washing water cannot be directly returned to the process, because the return process will destroy the water balance of the system and make the production impossible.

The zinc in the washing water is hydrolyzed and precipitated by neutralization, and the resulting precipitate is mainly zinc hydroxide, which also has a high water content. It will also bring water into the system as a raw material, so it cannot be directly returned to the process.

With the increase of oxidized ore processing capacity and the decrease of raw material metal grade, millions of tons of leaching slag will be discharged every year. If the zinc entrained in the slag is not recovered, tens of tons of metal loss will be caused. Not only waste of resources, but also cause serious pollution to the environment