Alkali leaching method of zinc oxide mine

Abstract

The invention relates to an alkali leaching method of a zinc oxide mine, belonging to the field of wet-process metallurgy of non-ferrous metal. The alkali leaching method comprises the following steps of: firstly carrying out calcining pretreatment on the zinc oxide mine as a raw material to decompose zinc oxide from smithsonite in the zinc oxide mine, controlling reaction temperature and reaction time by using an NaOH solution as a leaching agent, dissolving zinc in a leaching solution and then realizing solid-liquid separation through high-speed centrifugation to obtain a zinc-containing solution. The invention has the advantages of easy control of conditions, high leaching rate of zinc, good recovering effect, less varieties and low content of impurities in the leaching solution, convenient purification in the later stage, low production cost, no environmental pollution and can effectively utilize abundant low-quality zinc oxide mines in the southwest regions of China.

Description

technical field [0001] The invention belongs to the field of nonferrous metal hydrometallurgy, in particular to an alkali leaching method of zinc oxide ore mainly composed of smithsonite. Background technique [0002] With the decrease of zinc sulfide ore, zinc oxide ore is more and more concerned by the zinc metallurgical industry. Zinc oxide ore is a secondary mineral of zinc, which is formed by the oxidation and decomposition of zinc sulfide ore and replacement with carbonate or silicate in surrounding rocks, including smithsonite (ZnCO 3 ), Willemite (Zn 2 SiO 4 ), hydrozincite (2ZnCO 3 ·3Zn(OH) 2 ), hemimorphite (Zn 4 (H 2 O)[Si 2 o 7 ](OH) 2 )Wait. The grade of zinc oxide ore is low, generally 10-25%, and the phase is complex, the content of slime is large, the surface modification is difficult, and it is difficult to select and enrich. [0003] For the processing method of low-grade zinc oxide ore, the process of extracting zinc metal by wet method after hi...

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Problems solved by technology

The grade of zinc oxide ore is low, generally 10-25%, and the phase is complex, the content of ore slime is large, the surface modification is difficult, and it is difficult to select and enrich

[0003] For the processing method of low-grade zinc oxide ore, the process of extracting zinc metal by wet method after high-temperature pyro-enrichment is usually adopted, but this process has higher requirements on the grade of the raw ore, generally more than 20%. High efficiency, while the recovery rate of zinc is not high

[0004] Using sulfuric acid as a leaching agent to directly treat zinc oxide ore is a zinc smelting process studied in recent decades, but there are still many deficiencies, such as the problem of controlling the form of silicon in the leaching solution. When the acid dissolves, if the silicon in the ore forms a colloid Silicic acid will make it difficult to effectively separate the leaching solution from the leaching slag; zinc oxide ore contains a large amount of carbonate gangue, which will release carbon dioxide gas when it encounters acid, which will affect the reaction and deteriorate the working environment. Acid consumption; the metal impurity elements in the zinc oxide ore also react with the acid and dissolve in the leaching solution, so that there are many types of impurities in the leaching solution and a large content, which in turn increases the burden on the later purification process; the leaching equipment is severely corroded, etc.

[0005] In recent years, the alkaline leaching process of zinc oxide ore has attracted much attention. Using alkaline solution as the leaching agent, smithsonite in zinc oxide ore has the following reaction: ZnCO 3 +4OH-→Zn(OH) 4 2- +CO 3 2- Although the direct leaching of this alkaline solution is feasible, the leaching rate of zinc is generally low, usually only about 80%, and the zinc in the mineral cannot be effectively recovered.

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