Abstract: A method and an apparatus is described for the manufacture of fibrous material containing ligno cellulose for the production of fibre boards by the dry process, wherein cleaned and mechanically dewatered starting material such as hacked chips, hacked shavings or the like pass into a preheating stage and are subsequently broken down into fibre material. In order to use the water which arises on mechanical dewatering of the cleaned starting material which contains lignocellulose in a manner which is particularly friendly to the environment and also particularly economical, provision is made for the water which arises on dewatering a starting material which is cleaned by a mechanical process to be fed completely to a preheating stage.