Electrical Separation of Metals From Mineral Wastes Using Gradient Forces

This paper presents a method for recovery nonferromagnetic components (Au, Ag) in reduced concentration from mineral wastes, using gradient forces. First the main up-to-date electrical dry separation techniques for recovery useful materials from wastes are presented which are based on different electrical properties of the waste components.

Then, the main theoretical considerations reffering to electric gradient forces (typical for nonuniform fields) are presented. The theory shows how these forces together with other forces act on the particles of a mixture subjected to the separation process. Owing to combined actions of all these forces a superficial layer is obtained, consisting in metallic particles concentrated on the surface of mixture. Finally, the experimental results are presented, based on chemical analysis of the obtained superficial layer.