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Process for detoxification of CCA-treated wood.

ABSTRACT: A chemical process for detoxifying spent CCA (copper, chrome, arsenic)-treated wood, from which CCA and detoxified wood are recovered for recycling comprising the steps of (a) treating CCA-treated wood in the presence of a liquefying reagent such as an organic solvent at 100-250[degrees]C. with or without ferrous ions to form liquefied CCA-treated wood (b) adding water or an aqueous solution of an organic solvent to the liquefied CCA-treated wood with stirring to obtain an aqueous solution of liquefied CCA-treated wood (c) adding complexing or precipitating agents, such as phosphoric acid or calcium hydroxide to the aqueous solution of step (b) thereby precipitating insoluble heavy metal complexes or precipitates and forming a solution of detoxified CCA-treated wood (d) separating said heavy metal complexes or precipitates from the solution of detoxified liquefied CCA-treated wood and (e) isolating chromated copper arsenate from said heavy metal complex or precipitate.

ISSUE DATE: 9 Jan 2007. INVENTORS: Lianzhen, Lin (Kyoto, Japan); Hse, Hhung-Yun (Alexandria, Louisiana); Shupe, Todd Finley (Baton Rouge, Louisiana). ASSIGNEE(S): n/a. NUMBER OF CLAIMS: 12. PATENT NUMBER: 7,160,526.
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Title Annotation:Patents
Publication:Forest Products Journal
Article Type:Brief article
Geographic Code:1USA
Date:Jun 1, 2008
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