Comprehensive recovery method of material with high chlorine and low zinc

Abstract

The invention relates to the technical field of wet metallurgy zinc recovery, in particular to a comprehensive recovery method of a material with high chlorine and low zinc. The comprehensive recoverymethod of the material with the high chlorine and the low zinc comprises the step that after the material with the high chlorine and the low zinc is subject to oxidizing roasting, dilute sulphuric acid leaching, ammonium sulfate salting-out crystal, sulphation roasting, hot water dissolution and purification and impurity-removing, more than 99% of chlorine removes from the material with high chlorine and the low zinc, the enrichment of the zinc content can reach more than three times, recovery of metal zinc is facilitated through leaching and electrolysis, and the effect of low cost, high efficiency and obvious economic and social benefits is achieved.

Description

technical field [0001] The invention relates to the technical field of zinc recovery by hydrometallurgy, in particular to a comprehensive recovery method for high-chlorine and low-zinc materials. Background technique [0002] A considerable amount of zinc dust and zinc dross will be produced in the production of zinc alloy, die-cast zinc alloy and electrolytic zinc sheet melting and casting; this type of zinc dust and zinc dross has the characteristics of high chlorine content, so it is difficult to be directly used in electrolytic zinc Production, if the rotary kiln is used for redox roasting, since the volatilization temperature of the rotary kiln is 1100-1250°C, most of the chloride components will volatilize into the zinc oxide dust collection; if acid leaching or neutral solution is used to leach zinc oxide, the chlorine element It is easy to dissolve in the solution, resulting in high removal cost, and the excessive concentration of chloride ions in zinc sulfate seriou...

AI Technical Summary

Problems solved by technology

However, the process of electrolyzing zinc powder after alkali leaching is to use sodium hydroxide solution to leaching and then electrolyze zinc powder. The sodium chloride electrolyte obtained after enriching chloride ions to a certain concentration is difficult to return to use. It needs to be neutralized after zinc precipitation. The treatment of sodium chloride waste liquid not only affects the recovery of zinc, but also has a high cost of environmental protection treatment. At the same time, there are still problems such as high energy consumption, poor quality of zinc powder, and difficulty in expanding the scale after electrolysis of zinc powder after alkaline leaching.

The process of producing zinc sulfate by ammonia leaching also has the problem that it is difficult to return to use when the chloride ion enrichment content in the electrolytic raffinate is high, and it is difficult to purify and remove impurities in the ammonium chloride solution, and the solution is difficult to purify deeply. It is difficult for zinc to reach the quality standard of No. 1 zinc, and the electrolytic product is generally fragmented zinc, with a low casting rate and low economic benefits

Direct production of zinc sulfate crystals after ammonia leaching, because the zinc sulfate crystals produced by the process contain about 15% ammonia nitrogen, it can only be used in agriculture as zinc fertilizer, because it also contains a considerable amount of chlorine (mainly zinc chloride and ammonium chloride), long-term use will cause soil salinization, for this reason, also use P204 to extract zinc after leaching in sulfuric acid, sulfuric acid back extraction to obtain zinc sulfate solution, after concentration and purification, it is used for electric zinc production, so that chlorine The ions remain in the solution to separate from zinc, but because P204 extracts only about 50% of the zinc, the zinc content in the extracted liquid is still high, so it can only be returned for recycling. When the chloride ion content in the solution reaches 30g / When it is above L, it is difficult to recycle, and it can only be treated separately, which will lead to a large amount of waste residue and wastewater, low zinc recovery rate, and high production costs.

Images