Comprehensive recovery method of zinc oxide fume dust

Abstract

The invention relates to a comprehensive recovery method of zinc oxide fume dust. The method comprises the following steps: 1. performing alkali-washing on zinc oxide fume dust with Na2CO3 and NaOH in different stages: in the first stage of alkali wash, evenly mixing the zinc oxide fume dust and solid Na2CO3, adding water, stirring at high speed to dissolve the solid into solution with slag, and filtering to obtain first-stage alkali wash liquid and alkali wash slag; in the second stage of alkali wash, adding solid Na2CO3 and NaOH into the first-stage alkali wash slag, adding water, stirring to dissolve the solid, regulating the pH value, and filtering to obtain second-stage alkali wash liquid and alkali wash slag; and carrying out neutral leaching on the second-stage alkali wash slag, purifying and electrodepositing to obtain electric zinc; 2. leaching, displacing and the like to process the low temperature purified slag to obtain sponge cadmium; and 3. processing acid leached slag to obtain coarse indium, using high-temperature high-acidity leached slag as the raw material for recovering lead, and using alkali wash liquid for recovering thallium. In the invention, metals in ZnCl2, ZnF2 and PbCl2 form carbonate solid slag, chlorine and fluorine are dissolved in solution in the form of sodium salts, the slag and the liquids are respectively processed subsequently, and the products in every stage are refined processed to comprehensively recover zinc, cadmium, lead, thallium and indium.

Description

technical field [0001] The invention relates to a method for recycling soot produced in the metal zinc smelting process, in particular to a comprehensive recovery method for zinc oxide soot produced in the hydrometallurgy process. Background technique [0002] Zinc hydrometallurgy is a common process for metal zinc smelting. In the process of zinc hydrometallurgy, zinc oxide soot is a waste produced in large quantities. After removing F and Cl, a kind of soot is obtained in the process, that is, zinc oxide soot. Under normal circumstances, these soots contain valuable metals that can be recycled. For example, multi-hearth furnace zinc oxide soot contains 30-40% zinc, 10-20% lead, 3-8% cadmium, and 0.2-1.2 thallium. %, each ton of multi-hearth furnace zinc oxide soot also contains 400-1500g of indium, which has a high recovery value. However, because the fluorine and chlorine content in the zinc oxide soot is generally above 2% and 3%, the fluorine and chlorine content is r...

AI Technical Summary

Problems solved by technology

However, since the fluorine and chlorine content in zinc oxide soot is generally above 2% and 3%, the fluorine and chlorine content is relatively high, which seriously affects the electrolysis of zinc and makes the comprehensive recovery of valuable metals more complicated. There are still many technical problems to be solved.

At present, these zinc oxide soots in the prior art only use the method of preparing zinc sulfate series products to recover the zinc, and the recovery rate of zinc is below 86%. The cadmium, lead and high-value metals contained in zinc oxide soot and other soot Indium and thallium are not recovered, resulting in a large loss of valuable metal resources

In the prior art, those skilled in the art have tried various methods to recover valuable metals such as zinc, cadmium, lead, indium, and thallium. In order to eliminate the side effects caused by the high content of fluorine and chlorine, direct alkali elution was used in this field Chlorine method, the fluorine and chlorine removal rate of this method is below 80%, the fluorine and chlorine removal treatment in the follow-up process is still very difficult, and the cost is relatively high, it does not have the economic feasibility of industrial application, zinc, cadmium and The recovery rates of indium are 86%, 80% and 75% respectively, thallium has not been recovered, the comprehensive recovery rate is not high, and the lead content in the slag is about 35%, which is not conducive to further processing and recovery of lead

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