Method for recycling zinc from zinc leaching slag cleaning solution

Abstract

The invention discloses a wet process for recycling zinc from a zinc leaching slag cleaning solution, belonging to wet processing methods for zinc ore, in particular relating to a method for further recycling zinc from zinc slag generated by a zinc hydrometallurgy system. The method comprises the following steps of: washing leaching slag or rinsing the leaching slag with dilute acid; then preparing an organic phase by taking P204 as an extractant and kerosene as a diluent to extract a water phase; preparing a solution containing zinc and sulphuric acid; eluting impurities in the loaded organic phase; back-extracting the loaded organic phase with waste electrolyte and sulphuric acid; shifting zinc in the organic phase into a water phase again; carrying out deoiling treatment on all water phases in contact with the organic phase; and finally, adding a back-extracted solution as a new solution into a zinc electrodeposition system. The method has the advantages of simplicity of operation and high metal recovery rate, can effectively recycle zinc included in the zinc leaching slag so as to save resources and avoide environment pollution, and can be well linked with a zinc hydrometallurgy process so that the recovery rate of zinc is increased.

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 reduction of raw metal grades, millions of tons of leach slag will be discharged every year. If the zinc entrained in the slag is not recovered, tens of thousands of tons of metal will be lost. This is not only It is a waste of resources and also causes serious pollution to the environment.

[0008] The applicant once proposed a "wet process for recovering zinc entrained in zinc leaching slag" in Chinese patent application document 200610010819.1. Problems such as low recovery rate, waste of resources, and environmental pollution

However, in actual operation, sometimes the effect is unstable, and even the production cannot be carried out. After a lot of research, it is found that there are the following reasons: the accumulation of iron ions and other trivalent ions in the organic phase will greatly affect the metal. Recovery rate; Ca in the pre-extraction solution 2+ The existence of will also greatly increase the follow-up production cost, reducing the value of further promotion of the technical solution; the extracted loaded organic phase will increase the operation process when washing and removing impurities, and will generate washing waste water, which will lead to an increase in production costs ; The stripping solution is incorporated into the leaching system of the existing zinc hydrometallurgy process after degreasing, and the purification process of the conventional process is used to remove impurities, which will also increase the operating process and increase the cost

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