A process is dislcosed for recovering chips and fibers from residues of ter-derived materials, old pieces of furniture, production residues, water and other timber-containing materials glued with urea-formaldehyde binders or other binders capable of being hydrolysed or chemically disintegrated by disintegrating the timber-derived materials at a high temperature. In a first step of the process, the residues of timber-derived materials are impregnated with an impregnating solution and previously swollen until they have absorbed at least 50% of their own weight of impregnating solution. In a second step, the thus impregnated residues of timber-derived materials are heated up to 80.degree. C. to 120.degree. C. The thus disintegrated residues of timber-derived materials are then sorted by sieving and/or wind screening. The residues of timber-derived material have edges of at least 10 to 20 cm length. In an improved of the invention, the residues of timber derived materials are impregnated and heated at the same time.