Hot water separation process for copper and insulating material recovery from electric cable waste

Abstract

Recycling in the electric cable industry, especially the complete separation of metal and insulating material for re-use, has always been a problem. The present processes to recover copper and insulating material from cable waste involve the grinding of cables into smaller pieces to improve metal liberation from the insulating material. The method results in fine thread-shaped metal wedges in the insulating material, which prevents the re-use of the insulating material. A ‘hot water separation process’ was used to recover metal and insulating material from cable waste, with no need to grind the cable into smaller pieces to improve the liberation of copper from the insulating material. Based on the differences in coefficient of thermal expansion of the insulating material and copper, the cables are cut into a suitable length and placed into a blender with hot water. The insulating material and copper are separated and collected individually. By controlling the water temperature, blending speed and cutting length, complete separation can be achieved. This process is suitable for recycling many types of cable waste, including oil-containing wires, which are usually more difficult to recover.