Method for removing chlorine in waste zinc electrolyte

Abstract

The invention discloses a method for removing chlorine in waste zinc electrolyte. According to the method, excessive sodium sulfite is added into the waste zinc electrolyte to enable the whole waste zinc electrolyte to be in a reducing state; Cu2+ in the waste zinc electrolyte is fully reduced to Cu+, the reducibility of the waste zinc electrolyte is guaranteed, and Cu+ in the subsequent dechlorinated slag and dechlorinated slag treatment underflow is prevented from being oxidized; decoppered slag, a zinc leaching solution and the dechlorinated slag treatment underflow are added; an authigene product has a reduction reaction and a precipitation reaction in the solution through ingenious application of a zinc hydrometallurgy process, and chloride ions in a sulfuric acid containing zinc sulfate solution are removed. The content of chlorine returning to the chlorine in the leaching process is reduced. Accordingly, the requirement that the content of chlorine in the waste zinc electrolyte is lower than 300 mg / L home and abroad is met. The chlorine removal rate can reach up to 80% or above. Operation is easy. The practicality is high. At the same time, zinc is enriched in a decoppering solution, and the recovery rate of zinc is increased.

Description

technical field [0001] The invention belongs to the technical field of zinc hydrometallurgy, and in particular relates to a method for removing chlorine in zinc electrolysis waste liquid. Background technique [0002] At present, 80% of the zinc in the world mainly comes from the hydrometallurgical process. The general process of zinc hydrometallurgy is: roasting of zinc sulfide concentrate → leaching → purification → electrowinning. In the process of wet zinc smelting, a large amount of zinc electrolytic waste liquid will be generated. In order to reduce the loss rate of metal zinc in the whole zinc smelting process and reduce the discharge of wastewater from the zinc hydrometallurgy process, the waste electrolyte produced in the production process is generally After treatment, they are returned to the leaching system as the leaching mother liquor. With the rapid development of industrial technology, there is a shortage of zinc sulfide concentrate resources. In order to re...

AI Technical Summary

Problems solved by technology

The dechlorination agent of this method is mainly copper-containing slag or silver-containing solution. Although the chlorine in the zinc sulfate solution has a certain removal effect, the chlorine removal efficiency is not high, the loss of zinc is large, and the price of elemental copper and silver slag is high. It is difficult to control the process conditions, and it is rarely used in actual production

The ion exchange method has a high removal rate of chloride ions in zinc sulfate solution, but this method has high requirements for the selection of exchange resin and production parameters in the process of chlorine removal, and a large amount of waste water, limiting its application and promotion

The extraction method is to use a zinc extractant to enter the zinc in the zinc sulfate solution into the organic phase, and leave the chlorine in the water phase to achieve the purpose of chlorine removal. This method can achieve a separation rate of more than 95% between zinc and chlorine, but in zinc During the stripping process, there will be an organic phase entering the electrolyte, which will affect the zinc electrolysis process

The open-circuit heat separation contact method is to dissolve zinc sulfate and contact with heat separation to form a zinc sulfate solution for removing fluorine and chlorine and a gas containing fluorine and chlorine, so as to achieve the purpose of removing fluorine and chlorine in the zinc sulfate solution. Although the method is simple to operate, but The process will consume a lot of heat energy, resulting in a significant increase in production energy consumption

Images