Investigation of separability of particles smaller than 5 mm by eddy current separation technology. Part I: rotating type eddy current separators

Abstract

Owing to the growing emergence of the end-of-life electrical and electronic products with complex material structures and an ever-diminishing particle size of the valuable metals involved, development of eddy current separators (ECS) has been targeting selective separation of small non-ferrous metal particles smaller than 5 mm. Separability of various materials smaller than 5 mm, including fine copper wires, has been investigated using ECS with various design concepts. The present research work is divided into two parts, with Part I focusing on the rotating type ECS which are today common in practice, and with Part II dedicated to the ECS with novel concepts such as wet ECS technology. In Part I, three rotating belted-drum ECS were employed, which are manufactured by Bakker Magnetics, the Netherlands, Huron Valley Steel Co., US, and Eriez Magnetics, UK respectively. It is found that the belted-drum ECS are effective for separating materials below 5 mm if the magnetic drum rotates in opposite direction to the conveyor belt. The separation principle, particularly the 'backward phenomenon' of the rotating type ECS for small particles has been unravelled in the present study. Moreover, separation of Al from the 0-10 mm fraction of electronic scrap has been conducted. The results obtained demonstrate that the belted-drum ECS with appropriate design may be applicable for separation of small aluminum particles from electronic scrap.