A preliminary trial was carried out to see whether copper smelting process is able to recycle CCA treated timber. As a result of the first trial almost a full recovery of both copper and arsenic was achieved. Recovered metals were utilized in manufacturing CCA preservatives. The energy bound in wood is utilized in the flash smelting process and the burning gases are fed to the sulphuric acid plant. On the contrary chromium undergoes a slag treatment process where it forms insoluble compounds and is then removed together with the final residue. A trial was carried out at the copper line of Outokumpu Harjavalta Metals. Outokumpu Oy is the major producer of copper in Finland and the company also produces CCA preservatives for the Nordic market.

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