Method for producing high-purity nano-zinc oxide by ammonia decarburization of electrolytic zinc acid-leaching residues

Abstract

The invention discloses a method for producing high-purity nano-zinc oxide by ammonia decarburization of electrolytic zinc acid-leaching residues, wherein when leaching, 0.3-0.5kg of sodium fluorosilicate is added to per cubic meter of ammonia-ammonium bicarbonate solution, and then 30-60kg of slaked lime is added to per cubic meter of a leaching agent for performing decarburization and refining treatment; the method can obtain nano-zinc oxide powder with the purity greater than and equal to 99.7%, uniform particle size distribution (wherein the average particle size is 10-30nm), the specific surface area greater than and equal to 105m<2> / g, and excellent fluidity and dispersibility; the treatment method provided by the invention has the characteristics of low energy consumption, high efficiency, and higher economic and social values; all the valuable and harmful heavy metals in the electrolytic zinc acid-leaching residues are leached to be rationally used and cleaned with water; and finally, the obtained final leaching residues are turned from the electrolytic zinc acid-leaching residues as high-risk wastes into general solid wastes, thereby creating good economic and social benefits.

Description

technical field [0001] The invention relates to a production method of zinc oxide, in particular to a production method of high-purity nanometer zinc oxide. Background technique [0002] At present, zinc hydrometallurgy mainly adopts the production process of roasting-leaching-electrolysis, and the zinc content in the discharged electrolytic zinc acid leaching residue is generally 6-9% by mass ratio, and some can reach 20%. The phase analysis and X-ray diffraction analysis show that the zinc in the leaching slag is mainly composed of ZnFe 2 o 4、 It exists in the form of zinc silicate. At the same time, the mass fraction of sulfur is 6-12%, and the mass fraction of sulfate is 15-30%. 2+ , Pb 2+ 、Cd 2+ 、Ni 2+ , Hg 2+ 、As 3+ Plasma, its approximate mass fraction: copper 1%, lead 0.8%, iron 4%, silicon 3%, arsenic 0.3%, silver 0.003%, calcium 12%, magnesium 3%. In order to recover these zincs, the current treatment methods currently include fire method and wet method. ...

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 of ​​zinc oxide and its activity and dispersion, which in turn affects its application fields