Method for improving cadmium recovery through acid dissolution of cadmium sponge

Abstract

The invention belongs to the technical field of recycling of by-products of smelting engineering, and particularly relates to a method for improving cadmium recovery through acid dissolution of cadmium sponge. In the method for improving cadmium recovery through acid dissolution of the cadmium sponge, a copper and cadmium slag system is a system for mainly producing crude cadmium, copper slag and a lean cadmium solution with copper and cadmium slag generated from first-stage purification and second-stage purification of a purification system as a main raw material, wherein main components of the copper and cadmium slag are zinc, copper and cadmium, by adopting the principles that zinc, cadmium and compounds of zinc and cadmium are soluble in sulfuric acid, copper is not soluble in sulfuric acid, cadmium is substituted with zinc powder, and the like, the zinc, the copper and the cadmium in the copper and cadmium slag are recovered, the cadmium is substituted with the zinc powder, and is subjected to crude smelting in a metal form to produce the crude cadmium for sale, while the copper is enriched in the slag in a metal form, and is transferred to a copper company for recovery, and the produced lean cadmium solution is reacted with nickel and cobalt slag. By means of the method for improving cadmium recovery through acid dissolution of the cadmium sponge, loss of the metal cadmium in the cadmium sponge is reduced, a scrap rate of substitution of the cadmium sponge is reduced, the problems that during crude smelting of cadmium briquettes, briquetting is hard due to standard exceeding of a zinc content, material consumption is large during crude smelting, and the like are solved, and the copper and cadmium slag is recycled, so that stacking and storage of the copper and cadmium slag are reduced.

Description

technical field [0001] The invention belongs to the technical field of recovery and utilization of smelting engineering by-products, and in particular relates to a method for improving recovery of cadmium from cadmium acid solution. Background technique [0002] In the hydrometallurgical electrolytic zinc industry, a large amount of purified slag is produced in the pre-electrolyte electrolytic liquid preparation section, especially the pressure filtration of multiple purification processes. The purified slag contains high-grade cadmium. The purified slag has undergone pulping, chemical leaching and Impurity removal and purification to make a high-cadmium solution; at present, most electrolytic zinc enterprises adopt the mixed-phase replacement reaction mode. During the replacement reaction, a large amount of reducing agent zinc powder is wrapped by sponge cadmium, which cannot be completely reacted, resulting in zinc powder consumption during the replacement reaction. If it ...

AI Technical Summary

Problems solved by technology

[0002] In the hydrometallurgical electrolytic zinc industry, a large amount of purified slag is produced in the pre-electrolyte electrolytic liquid preparation section, especially the pressure filtration of multiple purification processes. The purified slag contains high-grade cadmium. The purified slag has undergone pulping, chemical leaching and Impurity removal and purification to make a high-cadmium solution; at present, most electrolytic zinc enterprises adopt the mixed-phase replacement reaction mode. During the replacement reaction, a large amount of reducing agent zinc powder is wrapped by sponge cadmium, which cannot be completely reacted, resulting in zinc powder consumption during the replacement reaction. Too high, the product sponge cadmium purity is low, the product quality is reduced, and the economic benefit of the enterprise is reduced

[0003] At present, the traditional cadmium recovery method mainly uses zinc powder as the reducing agent, and the reducing agent is added to the high-cadmium solution that is constantly stirred to recover the metal cadmium. The research shows that as the reaction progresses, the pH value of the solution rises, and the zinc powder A passivation film is formed on the surface, which hinders the further progress of the replacement reaction between metal zinc and cadmium ions in the solution, resulting in the incomplete reaction of some zinc powders with large particles, and the residual metal zinc is wrapped by the generated metal cadmium, and finally sinks to the bottom of the reaction tank Mixed into the product metal cadmium, the consumption of zinc powder is large and the purity of recovered metal cadmium is reduced. How to quickly and efficiently replace the cadmium ions in the solution has important environmental and economic significance