Main Production Methods of Zinc Powder

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Zinc powder, a form of zinc, is widely applied in the production life, especially in the mercury-free batteries, chemical, dyeing, pharmaceutical and pesticide fields, and painting, sodium hydrosulfite, electronics and food industries as well. The price of zinc powder is slightly lower than the average price of ordinary zinc and that price advantage has produced the exceptionally strong market demand for zinc powder, making the production of zinc become an urgent problem that needs to be solved.

Currently, there are three production methods of zinc powder, namely atomization (conventional atomization and composite atomization), distillation-condensation and electrolysis.

Atomization

Atomization is to melt and superheat zinc metal to about 660 degrees, and use medium pressure gas to atomize liquid zinc into fine metal powder. This production process is pretty simple and easy to operate at low cost and high productivity, but zinc powder produced via conventional atomization method usually is larger in average particle size. Fine powder output is rather low.

Distillation-condensation

This method is to heat Zinc metal to above 1000 degrees and volatile zinc vapor. Then zinc powder can be obtained after condensation. Zinc powder produced in this way usually has better activity, but the process is quite demanding on raw materials.

Electrolysis

Zinc powder produced through electrolysis generally has a large specific surface area and good activity. However, the current application is rather limited due to environmental protection reasons.
As atomization method has many advantages in the production of zinc powder, due to the deficiencies of traditional atomization method, a variety of composite atomization methods were developed on the market to improve atomization efficiency greatly and increase the powder yield as well. One of the more prominent is the multi-stage atomization process, in which the yield rate of 10~20 um size powders is higher than 90%. Multi-stage atomization process can be divided into the following two stages: Stage 1 is an ordinary gas atomization: let high-speed air flow react with the metal flow and broke it into tiny droplets. Stage 2 is impact atomization and centrifugal atomization that is to impact high-speed droplets on a rotating device to form double or multiple atomizations. Multi-stage atomization process can be divided into droplets crushing, heating and freezing branching processes. Each of the processes runs at the same time and influences with each other, determining the size and microstructure of the powder particles. However, this method is a little bit complicated and the process requirements are rather strict, the resulting quality of the final zinc powder is relatively excellent, thus making it one of the most commonly used zinc production methods.