Abstract: A method of burning pulverous raw materials in a rotary kiln is disclosed wherein the material is preheated and at least partially calcined prior to subjecting it to a finishing heat treatment such as sintering. The calcination of the raw material is accomplished prior to the final burning by feeding preheated at least partially calcined raw material to the upper inlet end portion of an inclined rotary kiln and mixing it intimately with a fuel capable of producing a combustible gas. The combustible gas thus produced is passed to a calcination chamber communicating with the upper end of the rotary kiln. Substantially uncalcined raw material is suspended in the gas mix while an oxygen-containing gas capable of supporting combustion in the calcination chamber is provided causing the oxygen-containing gas to be ignited and calcined substantially isothermally.

Abstract: A method is disclosed for heat treating a preheated pulverous raw material containing at least a portion of lime to produce a partial calcination prior to passing the raw material down through an inclined rotary kiln for further heat treatment. Partial calcining is accomplished by introducing into at least one end of a rotary kiln an amount of fuel sufficient for preheating, at least partially calcining, and substantially completely sintering the raw material, at least part of the fuel being introduced into the lower material outlet end portion of the kiln. An amount of oxygen containing gas sufficient for substantial combustion of the fuel introduced into the kiln is introduced into the lower end portion of the kiln, and preheated raw material is introduced into the mouth of the kiln in such a manner that the material is entrained in gases exiting from the kiln mouth.

Abstract: Method and apparatus for the thermal treatment of moist raw pulverulent material, particularly slurries of raw cement material, wherein a plurality of gas and material separators are connected in series, the material to be treated is introduced between the last separator and the next-to-the-last separator and penetration of infiltrated air into the gas stream is prevented by a blower in advance of the zone of introduction of the raw material.The blower prevents a large pressure differential at the point of material supply and at the same time accommodates maintenance of a high vacuum and rate of flow of gas for the transporting of the material. The gas conduit leading to the last separator has an elongated riser so that the moist material introduced into the gas stream is maintained in contact with the hot gases for a long period to effect efficient pre-drying of the material.

Abstract: A joint between a rotary kiln and a tiltable hearth furnace, characterized in that a part of the hearth furnace embraces the discharge end of the rotary kiln and the pivotal axis of the hearth furnace coincides with the axis of rotation of the rotary kiln at the joint between the rotary kiln and the hearth furnace.

Abstract: Grate burner fuel supplies additional heat to the grate preheater for accomplishing more calcining. A cooler recoup system directs cooler recoup air to the grate fuel burner as preheat combustion air for the fuel burner. The cooler recoup air is also directed to the grate preheat zone as preheated combustion air for fuel in the pellet bed. Cooler recoup air is also directed to the drying zone. The cooler recoup system is controlled so that excess cooler recoup air is bypassed to the waste gas system to dump excess air. Also, a cooler recoup fan speed or damper is regulated to control kiln firing hood pressure by varying the flow. In addition, there is provided the cooler recoup excess air bypass damper for controlling duct pressure to stabilize air flow in the system by varying the flow to the waste gas system.

Abstract: A method and apparatus for thermally treating fine granular material such as for the calcining of cement including a furnace for completing the thermal treatment of the material having a burner therein with the material is first received by parallel plural stage separator systems each having plural cyclone separators, wherein the material is heated by hot exhaust gases and material supplied from first and second separator systems to first and second parallely arranged preheater chambers each having their own burner and receiving the full flow of exhaust gases from a furnace to the separators feeding to the preheater chamber and the preheater chambers connected to discharge their exhaust gases to the separator systems, and the final stage of each separator system discharging the material directly to the furnace.

Abstract: Improvements relating to cement manufacture wherein a unique method and a plant for practicing the method are disclosed for removing at least a portion of gaseous compounds containing alkalis, chlorine or sulphur from the exit gases of a rotary kiln in which cement raw meal is burnt to cement clinker with a view to subsequent cement manufacture. The method comprises the steps of dividing the hot exit gases from the rotary kiln into a main gas flow and a separate divisional flow and directing the main flow through a suspension preheater for preheating cement raw meal prior to feeding the raw meal into the kiln. A plurality of individual relatively cool solid condensation bodies are directed to pass through the divisional flow under the influence of gravity to permit the alkalis, chlorine or sulphur to condense on the surface of the bodies and the condensed compounds are removed from the bodies for redirecting them into the separate divisional flow.

Abstract: This invention relates to an apparatus for calcining cement having a suspension preheater containing an auxiliary furnace in the preheater part, characterized in that said apparatus has an adjustable throttle positioned between a kiln and a mixing chamber where a combustion gas from the kiln and a combustion gas from the auxiliary furnace are joined and mixed with each other, said adjustable throttle comprising a quadrilateral flue where at least one of the walls is movable in order to control the amount of combustion gas from the kiln.

Abstract: This invention relates to a rotary kiln for the heat treatment of material and having a number of elongate satellite cooling tubes distributed uniformly around the rotary kiln periphery at the exit end of the kiln, the inlet ends of these tubes being connected by short inlet pipes to the interior of the rotary kiln, and each tube being supported on the rotary kiln casing by two support bearings which accommodate axial movement of the tubes relative to the kiln occasioned by thermal expansion or contraction of the tubes. Mounting of the bearing means accommodates a close spacing between adjacent tubes.

Abstract: A rotating kiln having two rotating cylindrical chambers, these chambers having colinear axes which slope below the horizontal from the upper or loading end of the first chamber. The material to be processed into light-weight aggregate is introduced to the kiln at the upper end of the first chamber which is of narrower diameter than the second chamber. The lower end of the first chamber unites with the upper end of the second chamber providing an annular inner face for the second chamber.

Abstract: Cement raw materials are precalcined prior to being sintered in a rotary kiln by feeding the materials in pelletised form downwardly through a gas or oil fired calciner in countercurrent to the flue gases drawn from the rotary kiln.

Abstract: A method and apparatus for thoroughly dispersing powdered material in a combustion chamber of a furnace in combination with a suspension preheater and a kiln to improve combustion efficiency. The material is introduced as a free falling stream in the upper zone of the combustion chamber and is contacted in the upper zone with recycled gases from a cooler and a second gas introduced at a higher velocity than said recycled gases, whereby the powdered material is thoroughly dispersed throughout said combustion chamber and heat exchange between the material and gases is enhanced.

Abstract: A rotary kiln plant for calcining and sintering mineral materials such as cement raw materials, comprising a separate unit for preheating and at least partially calcining the raw materials, a rotary kiln for sintering the preheated and calcined raw materials, a separate inside airswept rotary cooler means for cooling the materials burnt in the kiln, and a stationary chamber positioned intermediate the outlet of the rotary kiln and the inlet of the rotary cooler means and forming a passage for the burnt kiln product from the kiln to the rotary cooler means in countercurrent with heated cooling air passing to the rotary kiln. Air inlet and outlet means on the chamber make it possible to introduce additional cooling air and to utilize cooling air from the chamber for the preheating and calcining unit while by-passing the rotary kiln.

Abstract: Fine-grained material such as raw ground cement adapted to be fired in a rotary tube furnace is introduced to a vertical perheater and falls through a heating zone located at a level below the level at which the material enters the preheater. A stream of air enters the preheater at a level below the heating zone and passes upwardly at sufficient velocity to entrain the material that has passed through the heating zone, thereby causing such material to pass again through the heating zone. From the preheater the material is delivered to the furnace for final firing.

Abstract: A method and apparatus is disclosed for burning pulverous or granular material, particularly cement raw material to cement clinker. Burning of the pulverous material is accomplished in a plant which includes a suspension preheater, a rotary kiln and a separate rotary cooler unit having an inlet end and an outlet end, for cooling the burnt material exiting from the kiln by means of air which is subsequently used for combustion and preheating purposes. The method comprises dividing the heated cooling air into at least two streams, directing the divided heat cooling air out of both ends of the rotary cooler unit in its divided streams, directing at least one stream to the rotary kiln to be used as combustion air, directing exhaust gases from the rotary kiln to the preheater to preheat the material, and directing the other stream of heated cooling air to the preheater to preheat the material prior to being burnt in the rotary kiln.

Abstract: A method of burning pulverous or granular material in a plant including a suspension preheater and a rotary kiln having an integrally mounted planetary cooler for cooling the burnt material exiting from the kiln by means of air subsequently used for combustion and preheating in the plant.

Abstract: A method of burning or sintering fine-grain material which agglomerates above a critical temperature, such as cement raw meal, lime, dolomite, magnesite, in which the material is first preheated in a first zone, then flame heated in a second zone to a final treatment temperature and thereafter separated in a third zone from the hot exhaust gases of the second zone, the exhaust gases of the second zone being used for preheating the material in the first zone.