Method for producing zinc oxide by utilizing zinc-containing raw ore under zinc-ammonia complexing environment

Abstract

The invention relates to a method for producing zinc oxide by utilizing zinc-containing raw ore. The method comprises a primary extraction step, an optional purification step, a pre-treatment step, azinc precipitation step, a primary calcination step, a secondary extraction step, a pressurizing and crystallization step, a decompression and decomposition step, an optional rinsing step and a secondary calcination step. According to the method disclosed by the invention, wet-process leaching and a synthesis technology are combined to realize economical and environment-friendly utilization of low-grade zinc oxide ore and an applicable range is wide; ammonia steaming is not needed and the method is simple and feasible; the energy consumption of a technology is greatly reduced; high-temperatureand high-pressure potential safety hazards and equipment corrosion problems, which are caused by the ammonia steaming, are also avoided; the problems of technological recovery rate and high-quality product grade are solved; the pollution is small and materials are recyclable; the synthesis of calcium zincate under a zinc-ammonia environment is realized for the first time; a zinc oxide product isproduced through the calcium zincate; decomposition conditions of ammonium carbonate are creatively utilized in the technology and cyclic utilization of carbon dioxide is realized through pressure difference.

Description

technical field [0001] The invention belongs to the technical field of inorganic chemical industry, relates to resource utilization of low-grade zinc-containing raw ore, in particular to a method for producing zinc oxide by using low-grade zinc oxide raw ore. Background technique [0002] The production and consumption of zinc in my country ranks first in the world. Domestic zinc resources cannot meet the production requirements, and a large amount of zinc raw materials need to be imported every year. my country is a country rich in zinc oxide resources. The reserves of zinc metal in zinc oxide ore in my country are about 28 million tons, accounting for about 27.7% of the zinc metal reserves in zinc oxide ore in the world. Zinc oxide mines in my country generally have a low zinc grade, with an average grade of less than 5%. At present, the stagnant ore and lean ore reserves that cannot be economically utilized account for the vast majority, among which the mining tailings co...

AI Technical Summary

Problems solved by technology

However, due to the composition of low-grade zinc oxide ore and the economic investment in process equipment, when using 3-6% ultra-low-grade zinc oxide ore, the zinc concentration in the leach solution is difficult to reach 20 grams per liter, and the production of zinc oxide products per ton requires The evaporation of more than 50 cubic meters of zinc-ammonia complex liquid requires high energy consumption, and the volatilization of ammonia during the heating and evaporation process is not easy to control, which is likely to cause environmental problems. At the same time, the existing ammonia-ammonium bicarbonate process uses steam to directly In the heat exchange method, the excess water brought in by the steam affects the water balance and increases the environmental protection treatment pressure of the process; in addition, in order to ensure the zinc concentration in the complexation liquid, it is necessary to increase the concentration of ammonia water in the leachate, facing environmental problems caused by ammonia volatilization

[0008] Therefore, the existing technology is not satisfactory for the utilization of low-grade zinc-containing raw ore