Method for producing high-purity nano-zinc oxide by ammonia method using electrolytic zinc acid-leaching residues

Abstract

The invention discloses a method for producing high-purity nano-zinc oxide by an ammonia method using electrolytic zinc acid-leaching residues. The method comprises the following steps of: adding slaked lime being 1-5% of the mass of electrolytic zinc acid-leaching residues before a leaching step to perform activation, then leaching with ammonia-ammonium bicarbonate solution, adding 0.3-0.5kg of sodium fluorosilicate to per cubic meter of ammonia-ammonium bicarbonate solution, and refining after performing purification and impurity removal. According to the method for producing high-purity nano-zinc oxide by ammonia method using electrolytic zinc acid-leaching residues, the electrolytic zinc acid-leaching residues can be leached efficiently, the high-purity nano-zinc oxide with the purity up to above 99.7% can be obtained, and the high-purity nano-zinc oxide has high practical value and economic value; all the valuable and harmful heavy metals in the electrolytic zinc acid-leaching residues are leached and utilized, so that the obtained final leaching residues are converted from electrolytic zinc acid-leaching residues as high hazard wastes into ordinary solid wastes, the environment is protected, and the resources are rationally utilized.

Description

Technical field [0001] The invention relates to a method for producing zinc oxide, in particular to a method for producing high-purity nano zinc oxide. Background technique [0002] At present, hydro-zinc smelting mainly adopts the production process of roasting-leaching-electrolysis. The zinc content in the discharged electrolytic zinc acid leaching slag is generally 6-9% by mass, and some can reach 20%. The phase analysis and X-ray diffraction analysis show that the zinc in the leaching residue is mainly composed of ZnFe 2 O 4、 It exists in the form of zinc silicate. At the same time, the mass content of sulfur is 6-12%, of which the mass content of sulfate is 15-30%. The content of calcium and magnesium salts varies from place to place, and it also contains Cu. 2+ , Pb 2+ , Cd 2+ , Ni 2+ , Hg 2+ , As 3+ The approximate mass content of plasma is about: copper 1%, lead 0.8%, iron 4%, silicon 3%, arsenic 0.3%, silver 0.003%, calcium 12%, and magnesium 3%. In order to recover th...

AI Technical Summary

Problems solved by technology

The pyroprocessing process is long, requires a large amount of equipment maintenance, high investment, poor working environment, consumes a large amount of coal or metallurgical coking coal, low benefit, and large environmental pollution

Therefore, hot acid leaching or high-pressure leaching is usually used. These methods still have the following disadvantages: ①Consumption of a large amount of acid, ②The pressure of iron removal is high, and more reagents are consumed, ③The high-temperature and high-pressure equipment is seriously corroded, and the investment in complex equipment is large; ④ High operating costs and poor economic benefits

⑤The slag discharged at the end is acid slag, which brings new pollution to the environment, so it has to be solidified and landfilled, which not only pollutes the environment, but also wastes resources

[0009] 1) There is a large amount of calcium sulfate wrapped in the electrolytic zinc acid leaching residue, which makes the leaching of zinc difficult and the recovery rate is low

[0010] 2) Electrolytic zinc acid leaching residue contains 15-30% sulfate radicals, a large amount of ammonia is converted into ammonium sulfate, and ammonia consumption is high

[0011] 3) The conventional method directly purifies the zinc-ammonia complex solution after leaching, and finally removes heavy metals by zinc powder replacement method. Due to the presence of a large amount of free ammonia in the solution, the complexation of impurities is strong, and it is easy to produce back-dissolving phenomenon, which affects the purification effect, ultimately affecting the purity of zinc oxide products

[0012] 4) Due to the presence of a large amount of ammonium sulfate in the liquid, part of the zinc ammonium sulfate double salt will be precipitated during the ammonia distillation process, which will eventually affect the purity of zinc oxide

High-temperature calcination seriously affects the specific surface area and activity of zinc oxide, which in turn affects its application fields