Abstract: The invention relates to an apparatus for the classification of solid materials, preferably that of hard and highly pure materials, comprising a housing provided with an inlet stub, fine fraction outlet stub and a coarse fraction outlet stub as well as vane-crowns. The fluid carrying the material to be separated or classified radially passes through two vane-crowns with the vanes oriented at an angle to the tangent of the vane-crowns. Upon passage through the first vane-crown the separating or classifying chamber is reached whereupon the coarse fraction is separated out and the fluid flows radially through the second vane-crown whereupon the flow becomes axial with the fluid exiting against gravity and the separated material being collected below in a closed storage tank associated with the coarse product outlet stub.

Abstract: The invention relates to a lubricant of lubricating oil basis for lubricating rotating and/or sliding surfaces. Furthermore, the invention relates to a process for preparing this lubricant.The lubricant according to the invention comprises, beside the usual additives, 0.01 to 0.3 g/l of aluminium oxide power consisting of particles of 0.1 to 4 .mu.m in size.

Abstract: The present invention relates to a priming or body paint having active anti-corrosive and surface cleaning effect containing binding material, pigment and optionally solvent, filler and/or additives, characterized in that said pigment, optionally in addition to other known pigments, comprises:(a) 30-70% parts by weight, preferably 40-55% by weight of alumina hydrate (Al/OH/.sub.3),(b) 20-55% by weight of at least of one of atoxic oxides, hydroxides, oxide hydroxides, carbonates or phosphates of amphoteric elements or metals of variable valency possessing less valency than the maximum, in case of aluminum the oxide or hydroxide thereof,(c) 0-50% by weight, preferably 2-15% by weight of calcium and/or magnesium carbonate,and the grain size thereof is <20 .mu.m, preferably 2-10 .mu.m.

Abstract: An air-jet mill provided with pregrinding chambers and inner sizer suitable for fine grinding (below 10 .mu.), for cryogenic grinding and also for surface treatment during grinding of hard, elastic and/or thermoplastic materials.During operation there are no moving components to be exposed to heavy wear, and an inner sizer, forming an integral part of the grinding space, uses the energy left after grinding in the system to enable a sharp sizing or separation of fine fractions.

Abstract: According to the process the grains are led to the surface or ducts of a rotary element farther in than the flange of the rotary element, thus the coarse grains are led to the flange of the rotary element in a counterflow to the sizing medium. In a housing on an impeller deflecting elements are arranged, the carrier medium and the mixture of material to be sized are fed into the housing by medium inlet tubes, and led out by coarse and fine fraction outlet tubes or nozzles, and one inlet disc is arranged above the impeller so that they form an annular assorting space which is divided by deflecting elements into segments, and a passage connected to the inlet tube of the sizing medium is formed between the mantle of the inlet disc and the inner wall of the housing at its upper end, where ducts leading into the assorting space are arranged in the inlet disc farther in than its flange, and which are connected to the carrier medium inlet tube.

Abstract: The invention relates to an improved method for the production of liquid carbon compounds from coal. According to the invention coal is oxidized at 80.degree. to 300.degree. C. in the presence of the vapors of a C.sub.1-5 aliphatic alcohol, optionally under the introduction of steam, and then the liquid carbon compounds are separated from the resulting product mixture.The process according to the invention can also be performed under atmospheric pressure, 50-80% of the carbon content of the coal converted appear in the liquid product. The liquid product contains the more valuable fraction, boiling below 300.degree. C., as major component.

Abstract: The invention relates to an improved method for the liquid phase oxidation of coal performed with oxygen optionally in the presence of water. According to the invention oxidation is performed in the presence of a cooxidation partner selected from the group of liquid hydrocarbons and oxygen-containing liquid hydrocarbons, and if water is also present, the pH of the homogeneous solution formed from the cooxidation partner and water is maintained at a slightly acidic value.By the method of the invention the formation of carbon dioxide can be suppressed significantly.

Abstract: The invention concerns a process for the preparation of alumina and ferric oxide from low-grade aluminium and iron carriers. The processes, in addition to conventional technological steps, comprises the steps of dissolving the iron content of a ground, mineral material in an aqueous hydrochloric acid solution containing 200 to 420 g./lit. of hydrochloric acid at 90.degree. to 130.degree. C., eliminating the iron from the slurry of from a solution obtained by filtration of the slurry, with an anion exchange resin or semipermeable membrane or cloth, continuously or discontinuously, eluting the iron from the ion exchange resin and recycling hydrochloric acid and sulfuric acid in a closed system.

Abstract: A low grade aluminum and silicon containing starting material is intimately mixed with limestone and the resultant mixture is fluidized. The fluidized mixture is preheated to a temperature of 700.degree. to 900.degree. C., then held at sintering temperature for 5 to 10 minutes. Aluminum may be recovered by extraction of the sintered powder so produced.