A method for compound reduction and efficient recovery of rare and precious metals

Abstract

The invention relates to a method for compositely reducing rare and noble metals in a solution, which adopts a composite reducer to obtain the rare and noble metal concentrate from a solution containing rare and noble metals by direct reduction. The method comprises the following steps: pouring the solution containing rare and noble metals into an acidproof reactor with a stirring device, controlling the H<+> concentration and adding a halide ion soluble compound, introducing sulfur dioxide gas until the sulfur dioxide in the reaction solution reaches a saturated state, and adding hydrazine hydrate and hydroxylamine hydrochloride to perform composite reduction at certain reaction temperature; or adding a hydroxylamine hydrochloride-hydrazine hydrate composite reducer into the reaction solution to perform composite reduction at certain reaction temperature; and after the reduction reaction finishes, carrying out solid-liquid separation to obtain the rare and noble metal concentrate. The method can perform efficient composite reduction and enrichment of rare and noble metals in the solution, the reduction rate of selenium and tellurium is greater than or equal to 95%, the reduction rate of gold, platinum and palladium is up to 100%, and the formed rare and noble metal concentrate can be further separated to recover various rare and noble metals.

Description

Technical field [0001] The invention belongs to the field of rare and precious metal hydrometallurgy, and specifically relates to a comprehensive recovery and utilization technology of solutions containing rare and precious metals, which realizes the efficient recovery of rare and precious metals from the solution. Background technique [0002] Selenium and tellurium are two very important members of the rare element family. Due to the unique physical and chemical properties of selenium and tellurium, selenium has a wide range of uses in the fields of metallurgy, special glass, chemicals, electronics and agriculture. With development, the proportion of selenium consumption in different fields changes year by year, and the total amount is gradually increasing; tellurium is mainly used in metallurgy and electronics industries, accounting for more than 85% of the total consumption, and other main applications are glass, chemicals, and organic pesticides. etc. Gold, platinum and pal...

AI Technical Summary

Problems solved by technology

In the industry, zinc powder replacement is mainly used to reduce rare precious metals such as gold, platinum and palladium in the solution. Although the process is simple and easy to operate, the obtained reduced concentrate contains high impurities and low grades of precious metals, and the reduction of gold, platinum and palladium is not complete. The recovery rate of selenium and tellurium is basically zero, and the process is prone to side reactions to produce flammable and explosive hydrogen, which has become a major source of danger in industrial production

Document "SO 2 Recovery of selenium, tellurium and capture of platinum and palladium from the solution after reducing gold precipitation" (Chinese Journal of Nonferrous Metals, 2011, 21 (9): 2258-2264) and "A method for recovering rare and precious metals from solution" (Patent No. ZL 201010266679.0, Authorization announcement date: March 7, 2012), using separate gaseous SO 2 Selenium tellurium and gold, platinum and palladium are recovered by this method. Compared with the traditional zinc powder replacement process, the recovery rate of valuable elements is high, and high-grade concentrates are obtained, but SO 2 The reducing agent is easy to overflow and cause environmental pollution, which increases the treatment of overflow SO 2 the cost of

[0005] The present invention mainly provides a safe and efficient composite reducing agent, replacing the traditional zinc powder replacement or SO 2 Reduction process, recovery of rare precious metals in the solution, effectively avoiding the generation of H from zinc powder 2 hazard or SO 2 The pollution of the environment caused by gas overflow is more suitable for the needs of industrial production, making up for the shortcomings of traditional processes, obtaining high-grade composite rare metal concentrates, and providing high-grade concentrates for the next step of element separation