Vertical drum eddy-current separator with permanent magnets

Abstract

This paper presents a new vertical type of dynamic eddy-current separator, intended to be used for separating small conductive non-ferrous particles, having dimensions of about 2–8 mm. This separator, the so-called vertical drum eddy-current separator (VDECS) consists of a vertical spinning drum covered with permanent magnets, alternatively N–S and S–N orientated, directly fixed on the axis of an electric engine. The particles to be separated are brought into the field on an oblique trajectory, hit a shield which surrounds the drum and achieve a supplementary deflection. To increase the separation efficiency, high values of the drum revolution are not needed, but an appropriate arrangement of the separation parameters is. The results of grade and recovery for some types of wastes consisting of mixtures of different small conductive non-ferrous and conductive–non-conductive particles are given. Comparative to these results, the values of grade and recovery obtained for the same types of wastes using a horizontal drum eddy-current separator (HDECS), designed to separate millimetric particles, are given. The advantages of the VDECS lie in fact that the efficiency is close to the one of the HDECS, and the cost of the equipment is lower. The disadvantages are that the intermediate product must be passed again through a separation process.