In the process of copper scrap recycling, it mainly generated two types of off-gas that needs special environmental treatment. The low grade copper scrap, such as spent cable/wire, is burned to remove the insulation layer, during which large amount of particles, dioxin and sulfur dioxide, etc. The second main source is from melting and refining furnace where the copper scrap is refined to copper anode. The furnace flue gas is of high temperature, in large size, with various composition depending on the raw material.

Nowadays, workshops generally adopt mechanical/chemical/high temperature/ electrostatic/low temperature cooling approach for primary separation. It can reduce the charging of organics into the smelting furnace. The off-gas from furnace is mainly treated by combination of gravity sedimentation, cyclone dust collector and pulse-type baghouse. The sulfur dioxide generated needs to be washed by scrubber where the alkaline solution is used for desulfurization.