JSC “TsNIIolovo”, Novosibirsk, Russia:

V. E. Dyakov, Consultant, Member of Laboratory of Alloys and Fluxes, e-mail: dve106@gmail.com

There was investigated the process of zinc regeneration on laboratory centrifuge with in-tank rotary filter made of pressed conic plates. Molten hard zinc was intaken into the rotating filter cavity and pressed through the filtering gap, while dross crystals were cumulated in filter cavity. There were investigated the dross composition dependence on molten hard zinc composition, and the kinetics of zinc purification from iron by centrifugal filtration of molten hard zinc using in-tank filter. The optimal temperatures of filtration process were specified. The specific surface area of drosses was measured by argon adsorption method. The thickness of liquid zinc film was defined on the surface of FeZn₁₀ crystal. The necessity of crystallization enlargement of crystals is shown. There was defined the necessity of melt crystallization in the range of temperatures by 100 ^oC higher than filtration temperature. Thermodynamic calculations show Fe₂Al5 formation together with reaction of aluminium interaction with intermetallide FeZn₁₀. The optimal aluminium and iron ratio are shown together with their influence on iron output in drosses. The increased content of aluminium in melt is a condition of foam formation on melt surface. X-ray microanalysis defined that iron and aluminium compound crystals in drosses are covered with oxide film. Oxidized crystals form the foam on metal surface and make an influence of filtration productivity. There were defined the conditions of hard zinc filtration with foam formation during the crystallization temperature increase to 690 ^oC. There are given the parameters of industrial recycling of zinc by centrifugal filtration of molten hard zinc, obtained by various companies. 

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