To provide a method for covering lead contained in a residue and a produced oil when a plastic waste product containing a chlorine-based polymer such as polyvinyl chloride is changed to oil.
A lead component contained in the residue obtained from thermal decomposition of the plastic waste containing PVC taken out from a waste household electric appliances, etc., or in both the residue and the oil produced by thermal decomposition is extracted with an aqueous solution of an acid forming salt or complex having a larger solubility with Pb or a cheating agent (or water in some case), and then while alkali is added to the extracted solution, gas forming carbonate by an reaction with the lead such as gaseous carbon dioxide is blown in, thereby basic lead carbonate is precipitated, separated and recovered. As the gas to be blown into the extracted solution, gaseous carbon dioxide produced by the decomposition of plasticizers of a phthalic acid type, etc., contained in PVC in a thermal decomposition process is used.
TADAUCHI KIMIHIRO
GOTANDA TAKESHI
KADEN SEIHIN KYOKAI
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