Abstract: A process for the treatment of wooden elements, said process comprising the following steps: conditioning said wooden elements to reduce their moisture content; and a) performing one of the following sequences of steps selected from the group consisting of at least the sequence of steps b1) to b4) or at least the sequence of steps bb1) to bb2); said sequence of step b1) to b4) at least comprising: b1) impregnating the wooden elements obtained from step a) with at least one wood preservative, b2) heating the wooden elements obtained from step b1) at a temperature of at least 51 & deg; C.

Abstract: A wood article is submitted to a vacuum in an autoclave to remove air that it contains. Then, a solution which contains a water-soluble cross-linkable prepolymer, a polymerization initiator and optionally a wood preservative is introduced into the autoclave. Polymerization to form a polymeric network in the wood article is carried out in an atmosphere which may be substantially free of oxygen, while the optionally present preservative is chemically fixed to the wood. The result is a wood article with a permanently reduced hardness and an increased moisture content at equilibrium.

Abstract: A wood article is submitted to a vacuum in an autoclave to remove air that it contains. Then, a solution which contains a wood preservative, a water-soluble cross-linkable prepolymer and a polymerization initiator is introduced into the autoclave. Polymerization to form a polymeric network in the wood article is carried out in an atmosphere substantially free of oxygen, while the preservative is chemically fixed to the wood. The result is a wood article with a permanently reduced hardness and an increased moisture content at equilibrium.

Abstract: Preservatives and oil are extracted from treated wood. For this purpose, treated wood that is intended to be discarded is comminuted, the chips are impregnated with an alkaline solution until softening of the chips and modification of the chemical state of the products to be extracted. Possibly, the chips may be treated with saturated steam at a temperature between 170.degree. C. and 210.degree. C. followed by an explosive decompression giving wood fragments. This is followed by a refining operation in a crusher permitting the grinding of the wood. The result is a substantial release of the preservatives and oil from the wood chips which are at least partly disintegrated. The chemical preservatives and the oil are collected separately from the wood chips in the aqueous phases which are produced in the impregnation, steam cooking-explosive decompression and refining steps.