Abstract: A method and apparatus for burning fine grained products, such as in the manufacture of cement clinker from raw cement meal wherein preheated, calcined meal is heated in a separate heating assembly to a temperature from approximately 900.degree. C. to approximately 1250.degree. C. and is then sintered into clinker in a burning assembly such as a rotary tubular kiln. The present invention provides a means for achieving a fast and uniform continuous heating in the heating assembly without reaching the critical temperature of melt phase formation and without danger of encrustations, the heat required for rapid heating being released in controlled amounts in the heating assembly, where it is immediately absorbed by the product, the heat being provided by a plurality of points of fuel introduction and/or combustion air introduction distributed over the heating assembly.

Abstract: The leaching, precipitation and flotation method of recovering metals from ores is simplified by carrying out the leaching and precipitation steps simultaneously in the same reaction vessel. The method is particularly useful for recovering metals from low grade ores. During the leaching and precipitation step, mechanical comminution of the ore is also effected. The preferred reaction vessel is oscillated and the leaching and precipitation process is continuously effected by passage of the materials through the reaction vessel. The method is particularly suitable for recovering copper from oxygen containing copper ores.

Abstract: A method and apparatus is disclosed for the formation of lumps or pellets of mixtures of raw materials for glass. Soda and water are added to a mixture of the raw materials in a mixing container. The resulting mixture is at least partially heated for vaporization of the water and the mixture is compressed in a roller press. Pellets or lumps result which are fed to a heat exchanger for pre-heating prior to introduction into a melting furnace. Exhaust gases from a furnace are fed to the heat exchanger and also to the mixing container and a supply container for the roller press.

Abstract: A method and apparatus for the continuous recovery of tin of low iron content from an iron rich concentrate wherein the concentrate is smelted in suspension in an atmosphere ranging from neutral to weakly reducing to produce a smelt containing tin and iron silicates, the smelt is reduced with a gaseous reduction agent under conditions of high velocity jet treatment, the reduction being at a suitable reaction temperature and with a reduction potential of reducing gas so as to substantially prevent the reduction of the iron silicate to metallic iron.

Abstract: A method and apparatus for the preparation of coaldust for use with a preheater and a cement calcination apparatus. Exhaust gas from the preheater is mixed with a source of coal and input to a pulverizing mill. The output of the pulverizing mill passes through an air current separator and a cyclone separator. The output of the air-current-separator, a stream of coal gravel, is supplied as a fuel at a calcination point in the calcination apparatus. The exhaust output from the separator provides an input to the cyclone separator which separates coaldust from the gas. The exhaust from the cyclone separator is in part fed-back to a calcination point in the calcination apparatus and is also a part of the stream of gravel. The entire process is closed so that no burnable coaldust is lost to the atmosphere.

Abstract: A method and apparatus for the production of cement clinker low in sulphur from a calcium carbonate containing particulate raw material in an installation containing a multi-stage suspension gas preheater, a sintering furnace and a material cooler. A portion of the sulphur-containing exhaust gases issuing from the sintering furnace is separated, and the separated portion is preheated in the gas preheater. The material is heated in the hottest stage of the preheater to a temperature below the deacidification temperature. A reducing medium is added to the thus heated material. The remaining portion of the sulphur-containing exhaust gases is removed from the system for disposition.

Abstract: A novel kiln with overlying beds arranged about a central hollow shaft carrying rabble arms attached thereto and with alternate apertures formed in the floors between adjacent stories adjacent the hollow shaft and adjacent the periphery of the floor and with treatment gases being supplied through such orifices in a direction opposite to the direction in which the material moves through a furnace and further providing hot gas feed conduits located in the walls of the furnace in one or more stories and directed in a generally tangential direction relative to the story floors.

Abstract: A method and apparatus for the production of cement clinker from a raw material containing sufficient moisture to be agglomerated wherein the raw material is dried and subsequently subjected to calcining in a series of steps including preheating, deacidification, sintering and cooling. The exhaust gases are passed from the calcining step into the drying step. The raw material exiting from the drying step is pulverized into a fine powder and then transferred directly into the preheating step without intermediate storage.

Abstract: An apparatus for the thermal treatment of fine-grained material such as for the calcination of cement including a suspension type gas heat exchanger having a plurality of stages of progressively higher temperatures in the direction of material flow. A conduit connects the hottest stage of the heat exchanger with a rotary kiln. A combustion zone is provided within the conduit and rapidly oxidizing fuel components are introduced into this combustion zone. Slowly oxidizing fuel components are introduced into the rotary kiln in a second combustion zone.

Abstract: Iron, for example is directly recovered from relatively fine-grained (having a grain particle size range of less than 250 microns), iron-bearing ore whereby carbon-containing materials and oxygen-containing materials are fed through a molten metal bath and converted into a CO/H.sub.2 -rich reduction gas which is sequentially passed upwardly at gas speeds of at least 1.5 m/sec. through downwardly moving ore particles within a reduction apparatus comprised of a sequence of interconnected cyclones so that ore particles in each cyclone are in a state of suspension and in intimate contact with the reduction gas and each other whereby extensive reduction of the ore particles occurs at each cyclone so that after a last cyclone the so-reduced ore particles are directly fed into a smelting means, from which liquid iron is recovered.

Abstract: Method and apparatus for heat treatment of comminuted raw material of the type used, for example, for the production of cement in which the material is preheated in a preheater by means of hot exhaust gases from a kiln, the material is separately calcined for the deacidification of a portion of the calcium carbonate present and is subsequently burnt to completion in the kiln. The specific improvement of the present invention involves utilizing undispersed coarse pieces of fuel for the separate calcination and conducting the separate calcination at the material inlet end to the kiln.