Influence of material superficial moisture on insulation-metal electroseparation

The efficiency of electroseparating the constituents of a polyvinyl chloride (PVC)-metal (aluminium or copper) granular mixture depends on the moisture content of the materials. Laboratory research has been accomplished in order to determine the acceptable superficial humidity of the granules to be separated. The experimental study has been carried out on a roll-type laboratory separator with corona-electrostatic field. Ten samples of 50% PVC and 50% aluminum or copper, with a moisture content in the range 0<W⩽0.9%, have been identically processed. Several diagrams show the influence exerted by the humidity on PVC and metal recovery from the considered granular mixture. Efficient PVC-metal separations can be obtained for a moisture content of less than 0.3%. Experimental results are qualitatively discussed on the basis of the electrical charge of the PVC grain, the time constant of the discharge process, and the electric image force