Abstract: In order to improve the handling capability of red mud, it is mixed with fine-grain coal material such as brown coal or lignite in dust form, in a ratio by weight of between 0.5-10:1. The liquid present in the red mud is bound by the very fine coal admixed therewith so that the resulting mixture can be stored in a silo and even pneumatically conveyed, and the oily properties of the red mud are removed by the treatment. The mixture is particularly suitable for use in connection with the hydrogenating liquefaction of coal in which the red mud is used as a catalyst.

Abstract: In a process for separating sand from a brown coal or lignite material containing sand, wherein the sand is present entirely or predominantly in a grain size range covering only a part of the grain size range of the brown coal or lignite, with the grain size of the coarsest grains of the sand being markedly lower than the grain size of the coarsest coal grains, the coal in the grain size range between zero and at least the grain size corresponding to the maximum grain size of the sand is removed by a gaseous classifying operation, and the remaining material is subjected to a sieving or screening operation, the cut-off line of which is in the region of the grain size of the coarsest grains of the sand to be removed.