Abstract
This chapter represents the zinc and cadmium powders characterization and their production techniques. The evaporation-condensation method, inert gas condensation, the electrochemical method, melt atomization, mechanical grinding, and the cryogenic method are discussed. Galvanostatic, pulsed galvanostatic, potentiostatic, and a combined mode including galvanostatic and pulsed potentiostatic modes are compared for polarization by obtaining zinc electrolytic dendrite deposits. It is shown that all methods for production zinc powder are applicable for cadmium powders, but electrolytic deposition is the most common method. In addition, the cadmium powder production process by cementation from a solution of copper-cadmium cake in a waste electrolyte and the removal of copper from it is considered. Production of zinc- and cadmium-based alloys by the electrochemical method and by melt atomization is discussed. Safety measures in powder production and handling are discussed because of the high chemical activity of the fine and, particularly, the ultrafine zinc and cadmium particles. There are two basic sectors of application of zinc powders: protective coatings and chemical processes. The former includes zinc-rich primers and paints, powder coating, and the latter including purification of zinc solutions before electrolysis at electrolytic zinc plants, manufacture of reducing agents (sodium and zinc hydrosulfites) for the paper and textile industries, in the mining industry (for the extraction of gold, silver and other precious metals) and manufacture of alkaline batteries.
Published Version
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