Abstract: A method of treating plasterboard production scrap wherein the pieces of the plasterboard scrap having the plaster attached to paper components, is passed through an apparatus which comprises a cylindrical housing in which radial arms carry ploughshares riding along the wall of the vessel and cutting heads are provided between the paths of the ploughshares. The apparatus so reduces the pieces that a homogeneous mixture of fibers of the paper components and granular gypsum is formed. This product mixed with raw gypsum provides a calcinable mixture which can be calcined for use in producing additional plasterboard.

Abstract: The invention relates to a machine for handling pourable, pasty and/or fluid materials with disintegrating devices secured to the wall of the container. In known machines, to replace the disintegrating devices, it is necessary to remove them complete with the drive, for which purpose a relatively large opening is necessary in the wall of the container, and much time and work is involved. In the novel machine the shaft of the disintegrating device is made in two mutually separable parts so that the part carrying the pulverizing tools can be inserted and removed from inside the container, while the other part is permanently secured on the outside. It therefore requires only relatively small openings in the wall of the container and the opening, if not needed, can be closed off simply by the use of a plug-in cover. Insertion and removal of the tools is rapid and involves only a single screw.

Abstract: Mixing apparatus comprises a container which may be in the form of a hollow cylinder with its axis horizontal. It contains mixing means mounted to rotate within the container about its axis and in addition a pulveriser mounted in the cylindrical wall of the container. Whereas in known mixers of this kind the additional pulveriser comprises so-called knife heads which do not in every case grind down sufficiently rapidly and uniformly the material to be treated, in the mixer now proposed the grinding of the material is improved by the addition of a shearing effect. The pulveriser comprises two concentrically arranged relatively rotatable shearing rings and is in a position to disintegrate even materials which are difficult to treat, such as damp materials, rapidly and at the same time efficiently. Fluid can also be added in the region of the pulveriser without the material being caused to form into lumps.

Abstract: A plough-share like mixing tool for brushing the internal wall of a cylindrical mixer container is disclosed. The mixing tool is designed for attachment to the outer end of a radial arm and fixed on the shaft of a mixing mechanism rotatably mounted in the mixer.The reverse side of the mixing tool is designed to form a convexly curved envelope.