Abstract: A roll mill has a fixed roll journalled in stationary fixed bearings and a floating roll journalled in movable bearings enabling the floating roll to be pressed against the fixed roll under high pressure. An adjustable spacing arrangement is provided between the two bearings to enable a gap of selected width to be formed between the rolls. The spacing arrangement includes a pair of shaft-like distance members received and guided in associated bores of the fixed bearings for movement therealong. Free ends of the distance members extend outward of their bores and engage the opposing floating bearings to adjust the positions of the rolls as they wear so as to maintain the selected gap width. The free ends are retractable into the bores to allow the bearings to abut one another and thereby optimize the wear life of the rolls.

Abstract: The heat treatment of fine-grained material wherein two quantities of fuel are delivered to a precalcination zone at two different levels. The first quantity of fuel is delivered at a lower level nearer the combustion zone and the oxygen content of the gases passing through this region of the precalcination zone are such that in this region a substoichiometric combustion takes place and a CO content between 0.05% and 1% is established. As a result a reducing decomposition of the NO.sub.x content of the exhaust gases from the combustion zone takes place.

Abstract: The invention relates to a sifter in which the spiral for delivery of the air for sifting is divided into a plurality of channels lying one above another in which elements for setting the quantity of sifting air delivered to the individual channels are provided. In such a sifter the quantity of sifting air in the individual regions of the sifting chamber can be optimally adapted to the requirements, which leads to a substantial improvement in the degree of separation.

Abstract: Apparatus for the heat treatment of fine material comprises a multi-stage cyclone preheater, a rotary kiln and a calciner supplied with tertiary air from a cooler for precalcination of the preheated fine material. The tertiary air pipe is narrowed at the point where it joins into the calciner. In this way an intensification of the mixing together of material, fuel and gas is achieved as well as an improved combustion, particularly fuels which are slow to react.

Abstract: The invention relates to a multiple-stage heat exchanger 1 in which at least one of the lower heat exchange stages contains a deflector/separator with a horizontal gas inlet pipe and a gas outlet, and at least the upper heat exchange stage has a conventional cyclone. This results in a considerable reduction in the energy requirement, the size and height of the construction.

Abstract: The invention relates to a method of burning, calcining or sintering fine-grain material in which the burnt material separated from the gas flow is supplied to a residence container from which a part of the material is returned to the burning zone and the remainder of the material is supplied to the cooling zone. Such a method is distinguished by a low heat and energy requirement and by a simple construction of the apparatus and permits ideal adaptation of the burning conditions to the particular material.

Abstract: A process for the heat-treatment of fine-grained material which is preheated in a cyclone preheater, deacidified by additional fuel in a precalcination zone, and subsequently calcined to completion in a revolving tubular kiln. The gas temperature in the cyclone preheater and the material temperature after passage through the precalcination zone are measured, the difference between these temperatures is determined and, when the temperature difference reaches a maximum or minimum value, regulation of the fuel supply to the precalcination zone is switched to manual operation. In this way, the amount of fuel is rapidly adapted to the particular circumstances prevailing in the event of disturbances.

Abstract: This invention relates to a lifting wall for incorporation in a tube mill having two support plates divided into segments, intermediately disposed radially adjustable lifting vanes and a central transfer cone.

Abstract: The invention concerns an apparatus for crushing, by means of a rotary mill, material containing particles that are difficult to pulverize. The mill has an air-sifter with pneumatic supply of ground material, where the coarse-material discharge of the air-sifter is connected to the intake side of the mill, and has a mechanical conveyor whose intake side is connected to the coarse-particle discharge of the mill and whose discharge is connected to the intake side of the mill.