Method for preparing high-purity silver powder from silver-rich residue containing high selenium and tellurium

Abstract

The invention discloses a method for preparing high-purity silver powder from silver-rich residue containing high selenium and tellurium. The method comprises the steps that the silver-rich residue containing the high selenium and tellurium is mixed with alkali at a certain liquid-solid ratio and placed in a titanium reaction kettle to be leached, and after leaching is completed and filtering and washing are conducted, leaching liquid containing the selenium and the tellurium and alkali leaching residue containing the selenium and the tellurium are obtained, so that preliminary removing of the selenium and the tellurium is achieved, silver is enriched, and the selenium and the tellurium which exist in sulfides need to be further removed; the alkali leaching residue is added with nitric acid and placed in the titanium reaction kettle to be leached, and after leaching is completed and filtering and washing are conducted, acid leaching residue and acid leaching liquid are obtained; the leaching liquid is added with a precipitating agent to selectively form a silver chloride precipitation, and after filtering and washing are conducted, pure silver chloride is obtained, so that the selenium and the tellurium are completely removed; and the silver chloride precipitation is added with a displacer and subjected to displacement to obtain silver powder, and the silver powder is washed through deionized water and protected and dried through nitrogen, so that the high-purity silver powder is obtained. The method for preparing the high-purity silver powder from the silver-rich residue containing the high selenium and tellurium is simple in process, easy to operate and industrialize, environmentally friendly, low in production cost, high in selenium and tellurium removing rate and product purity and good in industrialization application prospect.

Description

technical field [0001] The invention belongs to the field of metallurgy of rare and precious metals, and relates to a method for preparing high-purity silver powder from silver-rich slag containing high selenium and tellurium. Background technique [0002] Silver-rich slag containing high selenium and tellurium is a kind of complex precious metal material, the main components are silver 50-60%, selenium 10-15%, tellurium 1-2%, antimony 1-3%, bismuth 0.2-1.0%, tin 0.1-0.5% %, copper 0.2-0.8%, lead 0.1-0.5%, iron 0.4-0.9%, etc., the silver part exists in the form of silver selenate, the rest exists in the form of copper selenide, and the tellurium exists in the form of copper telluride. How to extract selenium and tellurium, other metals are easier to separate from silver. At present, there are fire method and wet method for extracting silver from this slag. [0003] O. Zavinan and others invented a method and equipment for treating anode slime (invention patent number: 2005...

AI Technical Summary

Problems solved by technology

[0015] In summary, the method of preparing high-purity silver powder by alkali leaching--nitric acid leaching alkali leaching residue-immersion silver-replacement-nitrogen protection drying has not yet been reported.

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