The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 14, 2001
Filed:
Jun. 12, 2000
Erik Rasmussen, Gentofte, DK;
NKT Research Center A/S, Brondby, DK;
Abstract
A method for treatment of halogen-containing waste material, in particular PVC-containing waste material, is disclosed. The waste material is heated in a decomposition step in a reaction zone in a substantially closed system essentially without addition of water to a temperature between 150 and 750° C., preferably 250-350° C., in the presence of a halogen-reactive compound selected from alkali and alkaline earth metal hydroxides, alkali and alkaline earth metal carbonates and mixtures thereof, so as to establish a controllable autogenous pressure substantially above atmospheric pressure, in a sufficient reaction time to convert essentially all halogen present in the waste material to alkali or alkaline earth metal halides. The closed system preferably also has a condensation zone, where water vapor and volatile compounds liberated from the waste material are condensed. Remanence obtained in the decomposition step is washed with an aqueous solvent, preferably pure water, and the soluble and insoluble parts of the remanence are separated. By this method the halogen is removed from the waste without uncontrolled emission of halogen-containing acids to the environment.