A new technology for treatment of PVC waste

This paper presents a new environmentally sustainable technology for chemical recycling of PVC waste. The new technology transforms PVC waste into completely new chemical products/raw materials. The process is based on a combined thermal and chemical degradation of PVC in a reactor. In the reactor, the chlorine from the PVC reacts with fillers producing calcium chloride. The metal stabilisers (lead, cadmium, zinc and/or barium) are converted to metal chlorides. Exploiting the influence of pH, temperature, liquid to solid ratio and comminution on the metal solubility, metals and calcium chloride are sequentially extracted from the reaction product. This occurs in a downstream multi-stage extraction-filtration procedure. The products from the process are: (1) calcium chloride, which satisfies the specifications as thaw-salt, (2) lead (metal) product, which may be further purified and re-used, (3) coke and (4) organic condensate, which may be used as energy resources for the process. This paper presents the basis of the technology in terms of reaction and separation principles, selected process equipment and process design. Further the economy of the process, environmental issues and product purities/applications are addressed.