Abstract: A method for producing mechanical pulps which are useful for producing coated light weight paper, magazine paper and the like, is disclosed, which includes preheating lignocellulose-containing material in the presence of impregnation chemicals, refining the preheated lignocellulose-containing material utiilizing a pair of counter-rotating refining discs under pressure, bleaching the thus produced partially refined lignocellulose-containing material, and refining the bleached material in a second refining step utilizing a pair of refining discs, one of which is stationary and the other which is rotating under pressure.

Abstract: Method and apparatus for producing fiber pulp of improved paper-forming characteristics from ligno-cellulose-containing material such as wood chips and the like. The pulp material is subjected to a defibrating process in at least two steps. In the first step, the pulp material is disintegrated in a defibrator to form a flocculent mass of initially separated and freed fibers. This flocculent mass is then passed through a screw compacting device in which it is subjected to compression of a magnitude of 1 to 5 times the volume of the initially separated fibers. The compressed and highly concentrated mass of initially separated fibers is then passed into a refiner wherein the fibers are finally separated and fibrillated to form the final pulp.The refining is performed at a dry content of about 25-30%.