Method for recovering copper and cadmium from copper and cadmium slag and device for recovering cadmium from zinc sulfate solution rich in cadmium

Abstract

The invention discloses a method for recovering copper and cadmium from copper and cadmium slag and a device for recovering cadmium from a zinc sulfate solution rich in cadmium. The method comprises the following steps of firstly mixing copper and cadmium slag with a gas carrier substance uniformly; then using a sulfuric acid solution to carry out acid leaching on the copper and cadmium slag under certain conditions to leach all copper, cadmium and zinc in the copper and cadmium slag into the solution; then adopting zinc powder as a reducing agent to preferably reduce copper ions in the acid leachate into elemental copper to be precipitated under certain conditions, and adopting the device for recovering cadmium from a zinc sulfate solution rich in cadmium to selectively extract cadmium from the obtained zinc sulfate solution rich in cadmium, thus obtaining a high-grade sponge cadmium and zinc sulfate solution, wherein sponge cadmium can be directly subjected to casting-electrorefining or rectifying to obtain high-purity cadmium, and the zinc sulfate solution can be directly returned to an electrolytic zinc system to produce electrolytic zinc.

Description

technical field [0001] The invention relates to a method for recovering copper and cadmium from copper-cadmium slag and a device for recovering cadmium from cadmium-rich zinc sulfate solution. Background technique [0002] In recent years, my country's zinc smelting industry has developed rapidly, and its output has ranked first in the world for many years. Among them, the output of hydro-smelting zinc accounts for more than 70% of the total zinc output. In the zinc hydrometallurgy process, in order to obtain high-quality metal zinc, and in order to improve current efficiency and reduce power consumption, it is necessary to purify and remove impurity ions Cu, Cd, Ni, Co, etc. in the electrolyte before electrolysis. In industrial production, the two-stage replacement method of zinc powder is generally used to remove Cu, Cd, Ni, and Co, and produce copper-cadmium slag and nickel-cobalt slag containing a large amount of metal zinc respectively. Copper cadmium slag usually cont...

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Problems solved by technology

However, the pressurized acid leaching method is carried out under high temperature and high pressure, which requires high equipment, which is not conducive to the wide application of industrialization; the microbial leaching method is difficult to connect with the existing copper cadmium slag treatment system; the current efficiency of the fluidized bed electrode method Low energy consumption, high energy consumption, difficulty in deep separation of copper and cadmium, difficulty in engineering realization, etc.

[0008] Generally speaking, the existing treatment process of cadmium-containing slag has complex process, long treatment cycle, many types of chemical raw materials and equipment required, many intermediate by-product secondary materials, large consumption of zinc powder, and accumulated waste in the production process. There are many shortcomings such as more metal zinc, cadmium leaching rate, low recovery rate, cadmium is easy to disperse and lose during the lengthy treatment and recovery process, and it is the bottleneck that the current cadmium-containing material treatment technology urgently needs to break through.

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