Recycling of zinc from galvanising plant wastes by vacuum distillation

摘要

Zinc is an important metal which occupies fourth place after iron, aluminum and copper according to its output. Galvanising is the most common use of zinc. In the world large quantities of galvanising plant wastes are generated every year. Therefore galvanising plant waste is the most important recyclable zinc material. To conserve natural resources and to use up as little scarce landfilling space as possible, it is of great significance to recycle zinc from galvanising plant wastes.In this work a new type of half-industry scale vacuum furnace and the efficient technology for processing of the zinc-beading wastes generated by the galvanising process were developed. The experimental results showed that zinc from galvanising plant wastes could be satisfactorily recycled by vacuum distillation and the distillate containing more than 99.5 percent Zn could be produced. The direct recovery ratio of zinc was>= 90 percent and Fe content in the distillate could be lowered from 3 percent to 0.0025 percent at the temperature of 860 900deg C. The power consumption totalled 1500 approx 1600 kWh/t Zn. This process of vacuum distillation without preliminary refining and charge materials eliminates much of the air pollution associated with other classical processes, so it obviously has numerous advantages over existing technologies.