METHOD FOR UPGRADING WASTE MATERIAL COMPRISING SHEET METAL WITH A ZINC PLATING ON AT LEAST ONE SIDE THEREOF.

摘要

Method for upgrading waste material comprising sheet metal with a zinc plating on at least one side thereof, including a) subjecting the waste material to a mechanical processing step to improve the accessibility of said zinc layers to a subsequent chemical etching by increasing the accessible etching surface of the zinc layer portions, this being achieved by crushing the waste material to separate the sheets from each other and by producing cracks in said zinc layers; this step is advantageously conducted in a shredder/mill; b) subjecting the waste material to a chemical etching step to dissolve the zinc by immersing it in a basic bath; and c) separating the zinc-free sheets from the chemical etching bath containing the dissolved zinc, which is then recovered by electrolysis. The invention particularly discloses the use of the above method for recovering and upgrading new scraps of zinc plated sheets in the automotive industry.