Abstract: The invention covers a process for dehydration/filtration, and washing of red mud, if applicable with addition of sand, particularly from the Bayer process for aluminum production from bauxite, in which filters are used and caustic is washed out on the filter. The invention is basically characterized by washing and dehydration being effected under pressure above atmospheric with regeneration of bound caustic and production of a residue with a high solids concentration. In addition, the invention covers a plant for the implementation of the process.

Abstract: A device for transport of material between chambers at different pressures, comprises a feed chamber, a main chamber having an upper housing with an inlet and a lower housing with an outlet. The feed chamber is coupled to the main chamber at the inlet, and a first slide valve opens and closes the inlet. A second slide valve for opening land closing the outlet may be provided. At least one hollow gasket with an essentially closed wall, preferably an inflatable gasket, is provided between the upper housing and the first slide valve for sealing the inlet; and, at least one gasket with an essentially closed wall, preferably an inflatable gasket, may be provided between the lower housing and the second slide valve for sealing the outlet. Alternatively, a first flap valve for opening and closing the inlet is provided which is pivotally coupled to the upper housing at one side.

Abstract: The invention relates to a machine for pressing or dewatering and filtering of suspensions, sludges and the like with at least one driven endless pressure belt and further in particular at least one circulating endless filter belt, the pressure belt serving for the support of the filter belt. For the exertion of surface pressure onto the pressure belt, at least one frame-like, resilient, elastic hollow pad or a resilient, elastic hollow frame is provided, their interior being suitable for the admission of pressure medium and the pad or frame enclosing a pressure space, with a gap being provided at least during the admission of pressure medium between the hollow pad or hollow frame and the pressure belt.

Abstract: This invention relates to an improvement in the process for conditioning oil sludges, in which a wire cloth press is used as a separation device forming a pressed cake and including a sludge basin wherein mixing of individual sludges takes place and from which a suspension is removed, and further including intermediate stages for additions assuring the dehydration procedure, the improvement comprising adding structure-improving means to the suspension to increase the shear resistance of the pressed cake and to lower the filtration impedance. The invention also relates to equipment for performing the process.

Abstract: This invention relates to an improvement in a regulating apparatus for a dewatering machine, in particular a double strainer dewatering machine (sieve belt press), with one or more control circuits, for instance a flocculant control circuit and/or a flow rate control circuit, or a straining rate control circuit, to adapt to sludges or suspensions with varying dewatering properties, the improvement comprising means employing the rate of freely draining filtrate in the strainer zone as the criterion value for the flocculant control circuit.

Abstract: This invention relates to a device for regulating a water-removing or drainage machine, particularly a double-sieve sludge drainage machine having a plurality of automatic control means for adaptation thereof to sludges with different drainage properties, comprising an automatic throughput control means in which a sludge level in a filtering zone serves as an indication for the automatic throughput control means, an automatic flocculant control means adapted to employ shearing strength of a sludge-flocculant mixture as an indication of drainage behavior, and an automatic sieve velocity control means responsive in dependence upon drainage velocity.