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Remediation and recycling of WBP-treated lumber for use as flakeboard

Informally Refereed

Abstract

Laboratory-scale experiments were conducted in which preservative metals (As, Cr, & Cu) were thermochemically extracted from CCA-treated spruce (Picea engelmannii) using oxalic acid and sodium hydroxide. The effects of extraction time, temperature, and pH were examined and laboratory scale optimization was achieved. Two series of experiments were carried out. In the first series, the extractions were done at temperatures ranging from 20 to 80[degrees]C and with the pH of 1% oxalic acid solutions adjusted between 1.4 and 3.6 with sodium hydroxide. The second series of experiments were conducted to address practical considerations, such as the effect of mixing, liquid to solid ratio, and the presence of dissolved minerals in tap water (Sabo et al 2008). Based on these preliminary results, additional experiments are now underway to choose the conditions expected to be the most suitable for scaled-up extractions. Two candidate thermochemical extraction conditions were further studied to assess the suitability of the remediated woody materials to make engineered flakeboard. While the engineering and physical properties of the remediated flakeboard composite were similar, they were not equal to that of flakeboard made from matched untreated spruce. Still, these preliminary results were encouraging and the physical and mechanical property results similar enough that it is likely that with further laboratory-scale optimization, a high-quality flakeboard composite can be made from remediated waterborne preservative (WBP)-treated spruce.

Keywords

Preservatives, treatment, remediation, recycling, composites, flakeboard, composite materials, mechanical properties, temperature, spruce, sodium hydroxide, oxalic acid, recycled products, wood preservatives, recycling, particle board, copper, chrome, arsenic, waterborne preservatives, particle board, physical properties, preservative treated wood, treated wood, Engelmann spruce, chromated copper arsenate, thermochemical remediation, chromated copper arsenate, copper chrome arsenate, CCA

Citation

Sabo, Ronald; Winandy, Jerrold E.; Clausen, Carol A.; Basta, Altaf. 2008. Remediation and recycling of WBP-treated lumber for use as flakeboard. Proceedings, 104th annual meeting of the american wood protection association. 2008 May 18-20; Portland, OR. Birmingham, AL: American Wood Protection Association: 256-266.
https://www.fs.usda.gov/research/treesearch/33205