Abstract: Granular solid material is dried in a vertically extending annular chamber formed between inner and outer cylindrical walls by a current of high temperature inert drying gas of high humidity passed downward through the material. Material enters the chamber under gravity through a slot in the inner wall, which slot extends round the full periphery of the inner wall, and is removed from the bottom of the chamber by a variable speed discharge system, the rate of entry through the slot being governed by the rate of discharge from the bottom of the chamber so that the top of the column of material is of frusto-conical form. The spent drying gas stream, less a quantity which is discharged, is used to dilute the products of a fuel in air, the high temperature mixture thus formed constituting the drying gas. The quantity discharged has a mass equal to that of the fuel and air forming the products of combustion. An upward current of cooling air may be passed through the lower portions of the column of material.

Abstract: A horizontal circulating carbonizer comprising an annular horizontally rotatable circulating hearth disposed rotatably, a carbonizer body covering said hearth, a coal feeder equipped on the carbonizer body, a preheating zone disposed in the vicinity of said feed coal supply opening, a carbonizing zone connected to said preheating zone, a cooling zone connected to the carbonizing zone, and a discharger of cooled coke, and a process for the preparation of coke using this horizontal circulating carbonizer.

Abstract: Disclosed is a method for calcining pulverized raw cement materials or alumina materials prior to a burning process, a first kind of pulverized materials containing combustible compounds and a second kind of pulverized materials being simultaneously calcined.

Abstract: Extensive improvements in the production capability of the existing installations of the type comprising a rotary kiln and a suspension preheater unit are disclosed; that is, another suspension preheater unit provided with a calciner at its lowermost heat transfer stage and a distributor to direct a part of the preheated raw materials from the existing preheater to the calciner are installed, and all the raw materials supplied to two preheater units are uniformly and highly calcined ahead of the kiln in the preheaters by control of the distributor as well as the fuel rate to the calciner, thereby the production capacity of the kiln is doubled. Furthermore the accumulation of raw materials on the bottom of the calciner can be substantially eliminated and the specific power consumption of the installations may be reduced.

Abstract: Fine solid material is preheated in a first zone, then heated to the final treatment temperature by passing it through a flame in a second zone, and then separated in a third zone from the hot exhaust gases leaving the second zone. The separated exhaust gases are led to the first zone for preheating the material. A fuel feed stock is gasified to produce a combustible gas, and such gas is burned in the second zone to produce said flame.

Abstract: A plant is disclosed for heat treating pulverous raw material such as cement raw meal prior to a final sintering process in a rotary kiln. The plant includes a rotary kiln having an upper material inlet end portion for the reception of preheated cement material and a lower material outlet end portion for exiting the final sintered kiln product. A multi-stage cyclone string preheater having at least a first stage for receiving the cement raw meal has a last stage communicating with the upper material inlet end portion of the kiln. A smoke chamber connects the upper material inlet portion of the kiln with the preheater, and a scoop chamber connects the kiln with the smoke chamber. The scoop chamber is adapted to receive preheated, at least partially calcined raw material from at least one preheater stage other than the last stage.

Abstract: Sulfur oxides have a strong affinity for free lime and readily form gypsum anhydrite. By utilizing 2200.degree. F or higher on-gas containing reduced quantities of sulfur to the preheat zone of a material treating apparatus, large quantities of sulfur can be removed from gases evolved in the rotary kiln. Utilizing lower sulfur content on-gas to preheat will substantially improve the ability of the system to lower both sulfur and alkali levels in the clinker. Substantially free lime in the form of fines is introduced into the kiln off-gas stream to form gypsum anhydrite which is removed and has the potential to be utilized as a by-product. Essentially all of the remaining gaseous sulfur that has not been absorbed by the lime bearing dust is absorbed by the free lime in the pellets in the preheat zone of a material treating apparatus.

Abstract: Method and apparatus for the thermal treatment of moist, granular materials utilizing at least two superposed cyclone separators, with a relatively long gas conduit connecting the lower cyclone separator to the upper one. Charging means are provided in the conduit for introducing material to be treated near the lower cyclone separator, and a venturi-type constriction is provided in the conduit below the charging means, the constriction having its lower end projecting into the lower cyclone separator and serving to break up lumps of material which might otherwise be deposited in the cyclone separator and transfer the particulate material to the upper cyclone separator.

Abstract: Fine-grained material adapted to be fired in a furnace is discharged from a preheater into a gas conduit extending from the furnace to the preheater and through which a stream of hot gases pass. The conduit is shaped to deflect the gas stream and concentrate it along one side of the conduit in the area of introduction of the material to the conduit. Below the area of introduction of material to the conduit fuel burners provide a heating zone through which the material falls. The concentration of the gas stream along one side of the conduit assures entrainment of the material in the gas stream and passage of the material again through the heating zone. Above the area of introduction of material to the conduit the latter is shaped to deconcentrate the gas stream and permit some of the material entrained therein again to fall downwardly through the heating zone, following which such material is reentrained in the gas stream.

Abstract: Fine-grained material is heat treated by being preheated and then is heated to its calcining or sintering temperature, following which it is again heated to such temperature and subsequently cooled. The concentration and residence time of the material during its second heating are greater than they are during its first heating, and the concentration of oxygen is greater during the first heating of the material than during its second heating.

Abstract: A method is disclosed for heat treating pulverulent or granular raw material such as cement meal. Raw material is directed to at least two multi-stage preheater strings, the first string communicating with the kiln by a smoke riser pipe and the second string having a calciner positioned at its lower end portion. The raw material directed to the first preheater string is divided into two divisional flows with the first divisional flow comprising substantially the maximum amount of material which can be substantially completely calcined by hot gases exiting the kiln. The first divisional flow of raw material is directed toward the upper material inlet end portion of the kiln so as to be entrained by the hot gases exiting the kiln, and the hot kiln gases and entrained material are directed to the first preheater string. The second divisional flow is directed to the second preheater string where it is calcined either alone or with raw material directed to the second string.

Abstract: This invention relates to a device for the heat treatment of fine material, including a rotary tube furnace, a multi-stage pre-heater heated by the exhaust gases from the rotary furnace and a zone through which the exhaust gases flow and provided with rotary lifting members, with the material extracted from the second stage of the pre-heater being fed into said zone before it is fed from the furnace exhaust gases from the first stage of the pre-heater and then reaches the rotary tube furnace.

Abstract: A method and apparatus for introducing a particulate or pulverulent material into a tube or duct in which material is pneumatically transported by a gas flow and possibly simultaneously subjected to some kind of treatment. The material is currently thrown into the duct as a continuous stream or bed, for example by means of a fast moving conveyor belt. Before the stream of material reaches the said duct it is exposed to one or more transversely directed gas jets for spreading the particles in the stream and directing them into the duct through an inlet opening therein.

Abstract: Coal to be supplied to a coking oven is pre-heated, in a single pre-heating zone, such as in a conveying riser, first by heat yielded to it by a gaseous carrier medium entraining the coal for joint passage through the riser, and then additionally pre-heated by heat yielded to it by a gaseous fluid, such as hot combustion products, introduced into the pre-heating zone at a region thereof at which the temperature of the coal has already risen to a predetermined value, such as 80.degree. to 100.degree. C. The additional pre-heating of the coal results in a final temperature of the latter at the exit of the riser of more than 130.degree. C, preferably between 150.degree. and 250.degree. C. The stream of the carrier medium with the coal entrained therein flows upwardly through the riser which is substantially vertical, the coal being entrained at the lower end and separated from the mixture of the carrier medium with the gaseous fluid at the upper end of the riser.

Abstract: In a pneumatic dryer, a material which gives off an odorous exhaust during drying is dried in a first dryer section by a stream of hot gas, the major part of the spent gas stream being re-heated by the addition of air and burning fuel under pressure to form the said stream of hot gas. The excess spent gas in the first dryer section is passed through an incinerator to pyrolyze the odorous content of the spent gas stream, and the pyrolyzed gases are used to dry a second wet material in a second dryer section and are then passed to atmosphere. The second wet material does not give off an odorous exhaust. In a modified method a wet material which gives off an odorous exhaust when the moisture content of the material falls below a critical value during drying is dried in the second dryer section to a moisture content having a value above the critical value and is then dried to completion in the first dryer section.

Abstract: Nongaseous carbonaceous material is heated by a method comprising introducing tangentially a first stream containing a nongaseous carbonaceous material and carbon monoxide into a reaction zone; simultaneously and separately introducing a second stream containing oxygen into the reaction zone such that the oxygen enters the reaction zone away from the wall thereof and reacts with the first stream thereby producing a gaseous product and heating the nongaseous carbonaceous material; forming an outer spiralling vortex within the reaction zone to cause substantial separation of gases, including the gaseous product, from the nongaseous carbonaceous material; removing a third stream from the reaction zone containing the gaseous product which is substantially free of the nongaseous carbonaceous material before a major portion of the gaseous product can react with the nongaseous carbonaceous material; and removing a fourth stream containing the nongaseous carbonaceous material from the reaction zone.

Abstract: Pourable particulate material is accommodated in a vessel. A stream of gaseous fluid is directed into the lower end of the vessel and is split up into a high-speed first flow and a second flow. The material surrounding the bottom end of a central upright unobstructed passage in the vessel is entrained by the first flow and conveyed upwardly to be deposited on top of the body of material in the vessel; since new material from the body slides down about the lower end to be entrained in this manner, the body of material is gradually turned over in the vessel. The lower-speed second flow is directed through the body of material outside the passage to trickle through the material and subject the same to a treatment.

Abstract: A method of calcining solid materials on a downdraught travelling grate prior to treatment at a higher temperature on a continuously operating kiln, wherein heat for said calcining is obtained by drawings hot gaseous effluent from the kiln into the travelling grate through the solids discharge outlet thereof, characterized in that additional heat from an auxiliary source is induced into a downstream portion of the travelling grate.

Abstract: A method of preparing plaster by brief contact between gypsum and a hot gas. The method comprises introducing the gypsum through the axial tube of a nozzle, around which a helical stream of hot gases is created, and bringing the two phases into contact in a vessel at the outlet of the nozzle. The method of the invention makes it possible to vary the quality of plaster produced and to use either dry gypsum or dilute gypsum pastes as the starting material.

Abstract: Fine grained material such as raw cement meal is preheated in a preheater and discharged from the latter into a rotary kiln for calcining and through which hot exhaust gases pass in counterflow to the material. Immediately after introduction of the material to the kiln fuel is sprayed onto the surface of the material and is covered either by additional material from the preheater or by circulation of the material already in the kiln, due to rotation of the kiln at an elevated speed. The fuel is combusted virtually entirely within the kiln and substantially directly at the material without previous gasification of the fuel.

Abstract: Wet particulate coal and a current of hot dry gas at superatmospheric pressure are introduced into a substantially closed drying chamber to contact the material with the gas while maintaining the drying chamber under superatmospheric pressure so that the material is dried by the gas. The dried material is withdrawn from the drying chamber and the gas is withdrawn from the drying chamber and itself mixed with a stream of hot dry gas produced by burning a combustible and a combustion-supporting gas. This mixture is then reintroduced into the drying chamber as the current of hot gas used to dry the coal. The burner is operated at superatmospheric pressure and is formed of a jet-pump type injector, and a diffusor is provided downstream of this injector in the circulation path.

Abstract: A method is disclosed for burning pulverous or granular raw material such as cement raw meal in a rotary kiln plant by directing a first flow of raw material to a cyclone preheater, preheating the first flow of raw material in the cyclone preheater, and directing the preheated raw material from the cyclone preheater to a rotary kiln for burning the material in the kiln. The burnt kiln product is directed to a cooler which may be of several types and which communicates with the material outlet of the kiln while a second flow of fresh raw material is directed to the cooler to at least partially cool the burnt kiln product by transferring heat therefrom to the second flow of fresh raw material in the cooler.

Abstract: In a slagging gasifier the slag quenching chamber is provided with means having a plurality of equispaced outlet ports disposed around the inside of the upper region of the chamber, each outlet port communicating with a venting control which may be used selectively to vent the normally pressurized quenching chamber to atmosphere during a slag-tapping operation.

Abstract: Techniques for regulating calcining processes, particularly the calcining of lime containing materials, which are supplied as pulverized raw material, into cement clinkers in a cylindrical rotary koln, provides that the exhaust gas preheats the raw material and the calcined material preheats the combustion air. The quantity of raw material and the quantity of combustible material, the temperature of the combustion air and of the exhaust gas, as well as the composition of the exhaust gas, and additional parameters of the process are continuously measured and partially controlled. From the continuously measured individual values of the process a characteristic value describing the condition of the process, particularly the supply of heat, is formed, and is utilized to regulate the calcining process.

Abstract: A mixer-granulator, preferably a spiral path granulator, is combined with a pneumatic conveyor dryer in a process for converting a solution or suspension into a dried particulate product. In a preferred embodiment, the particles formed in the mixer-granulator show a non-equilibrium moisture distribution with an interior part of lower moisture content and a surface part of higher moisture content.

Abstract: An installation for the manufacture of cement in a rotary tubular kiln comprises a combustion chamber upstream of the kiln, two preheaters for the raw material, one of the preheaters receiving hot gases from the kiln and the other preheater receiving combustion gases from the combustion chamber, and a cooler receiving the clinker from the kiln. One of the preheaters is a multi-stage preheater and all of the raw material is introduced into the one preheater one of whose stages is arranged to divide the raw material into two fractions. One of the raw material fractions is passed sequentially into the other preheater and into the combustion chamber while the other fraction is passed sequentially into the other stages of the one preheater and into the combustion chamber.

Abstract: The quench chamber of a slagging pressure gasifier is provided with a perforated tubular air ring remote from the slag tap main burner of the gasifier and arranged, in use, to supply the burner with a secondary air supply and, at the same time, to set up an air circulation adjacent the walls of the chamber above the normal water level therein, thereby to cool the walls. There is further provided a nozzle mixing ring burner for use in a slagging gasifier comprising a body having two integrally formed chambers each having respectively a gas inlet and outlet and an air/oxygen inlet and outlet. The outlets are directed toward a shaped annular portion on the inner periphery of the ring body.

Abstract: A method and an apparatus is disclosed for producing such as Portland cement from pulverant raw material in a system having at least a preheater and a rotary kiln. The preheater may be of the type having a series of stages each provided by a cyclone dust separator for successively preheating the raw material in a counterflow of kiln waste gases and in which an identified one of the stages discharges a gas flow containing more thermal energy than can be used to advantage in preheating material in the remaining stages through which such gases must pass before dispersing in the surrounding atmosphere. A portion of the gases passing from the identified stage is diverted to a heat exchanger which utilizes the heat energy in such kiln waste gases to heat a clean stream of air.

Abstract: Apparatus and process for continuously pyrolyzing or gasifying a particulated carbonaceous feed material in which preheated heat-containing bodies or pebbles are admixed with the feed material in a stratified manner to form a downwardly moving columnar reaction mass, with a remaining portion of the pebbles substantially devoid of any feed material disposed in a surrounding layer relative to the reaction mass. Gas is continuously passed transversely through the reaction mass and surrounding layer in a manner to sweep the gaseous pyrolysis reaction products out of the reaction chamber, and wherein the layers of pebbles surrounding the reaction mass serve to effect a deposition of carbonaceous residue, preventing encrustation and fouling of the reactor system.

Abstract: Fine-grained material such as raw ground cement adapted to be fired in a rotary tube furnace is introduced to a vertical preheater 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: The combustion air, which is induced into a calcining furnace (calciner) from the lower end thereof and is vigorously swirled upward along the furnace wall, is burned by a plurality of burners and the negative pressure region may be developed at the center portion of the furnace. The exhaust gases leaving a rotary kiln, in which the calcined raw materials are burned to clinker, are led upwardly from the center of the furnace bottom into the said negative region and mixed with combustion gases. The raw material particles may be fed directly into the said negative region or to kiln exhaust gases so as to be entrained into the said region.

Abstract: Processes for preparing agglomerates containing iron oxide and suitable for charging as a feed material into a blast furnace and apparatus for effectively carrying out these processes. Waste matter from commercial iron and steel operations containing iron oxide and combustible matter is charged as feed into a rotating cylinder where it is ignited by flame from a jet; then an oxygen containing gas is passed under pressure through a wind box upwardly through passages through the walls of the cylinder and upwardly through particles of burning, tumbling particles of feed matter as this matter moves as a stream and comes into agglomerate form. The treated material is discharged in agglomerate form at the end of the rotating cylinder. These agglomerates may be effectively utilized as iron bearing feed material by charging them along with other charge materials into a blast furnace.

Abstract: Fine grained material such as ground raw cement is delivered in a stream from a preheater to an upright gas conduit through which furnace exhaust gases flow to the preheater. In different cross-sectional areas of the conduit the velocity of the gas differs. The stream of material falls upon a distributor in the conduit to distribute the material over the cross-sectional area of the conduit. The distributed material falls through a combustion zone and a substantial fraction of such material is entrained by the exhaust gas and passes again through the combustion zone enroute to the preheater. The distributor is adjustable to enable the concentration of material in different cross-sectional areas of the conduit to vary according to differences in the gas velocities in such cross-sectional areas.

Abstract: Variable dual orifices in the restricted portion of the flue between the kiln and the preheater provides a controlled bypass of 0 to 100% of the kiln gases around the preheater and prevents short circuiting of process materials from the precalciner and mixing chamber to the kiln and provides a means for adjusting the orifice and system pressures to thereby provide stability of operation and control over the entire range of bypass; positive isolation of kiln gases from preheater gases during 100 percent bypass operation is ensured.

Abstract: A method of heat treating a material, particularly for the despersion and firing of wet agglomerates, slurries, sludges and the like in fluidized bed, spouting bed or spouting/fluidised bed combustors, comprises extracting hot sold particles from the bed of the combustor, mixing the hot particles and the material in a mixing chamber, and conveying at least part of the product of the admixture to the combustor. Apparatus is also provided for heat treatment of a material by this method.

Abstract: There is disclosed a method of burning a ceramic shell mold for use in precision casting for curing the ceramic shell mold. The ceramic shell mold is positioned within a heating compartment while a mass of sand within the heating compartment is fluidized so as to submerge the ceramic shell mold thereinto. Thereafter, particles of the sand are heated to a predetermined curing temperature, which sand particles then heat the ceramic shell mold enveloped by the sand particles.

Abstract: A method is disclosed for heat treating granular or pulverulent raw material wherein the raw material is directed to a heat exchanger having at least two preheating units operating in parallel, each preheating unit having at least a first preheating stage and at least a lowermost calcination stage to effect a preheating and at least partial calcination of the material. The preheated, at least partially calcined material is fed from the heat exchanger into a kiln and undergoes a sintering process in the kiln. The sintered material is directed from the kiln into a cooling means in which cooling air is directed in a manner to effect a heat exchange between the material and the cooling air.

Abstract: A method for the heat treatment of fine-grained materials containing alkali compounds which liquify at critical temperatures comprises pre-heating the materials and discharging them to a rotary kiln in counterflow to the kiln exhaust gases, and introducing cooling air to the kiln in such quantity and at such temperature as to reduce the temperature of the exhaust gases to a level lower than that required for the compounds to liquify.

Abstract: A chamber which forms a material inlet and an exhaust gas outlet at one end of a rotary kiln has an inclined bottom arranged to cause preheated fine material deposited thereon to slide by gravity into the end of the rotary kiln. A dense stream of fine granular material is deposited on such inclined surface, and fuel in finely divided form is introduced into the dense stream of material flowing down the inclined surface to cause the fuel to become intimately mixed with the material. Gas is discharged from the kiln in contact with the stream of material as such a velocity as to entrain a substantial proportion of such stream, the temperature and composition of the gas being such as to cause combustion of the fuel mixed with the entrained material.

Abstract: A method in which activated carbon having a bulk density of at least 0.35, a particle size of 5 to 40 mesh and a water content of 50 to 120% is regenerated by being passed successively through drying, burning and reviving treatment zones of a vertical columnar furnace, which zones are maintained within temperature gradients such as to prevent explosion and oxidation or destruction of the carbon due to overheating while the carbon descends through the zones and is heated by a high temperature combustion gas flowing upwardly through the treatment zones at a rate not exceeding the minimum rate of fluidization of the descending carbon.The regenerating apparatus or furnace has gas burners mounted thereon to deliver combustion gas tangentially to a header and then to distributing ports arranged circumferentially around and internally of a columnar bed of carbon being regenerated to provide uniform temperature distribution across the bed.

Abstract: Raw material for making cement is treated in an installation comprising a plurality of superimposed cyclones constituting a multi-stage exchanger wherein the solid raw material and gases issuing from a clinkerization furnace circulate counter-currently, and wherein at least a portion of the raw material issuing from the penultimate exchanger stage is injected into the gas current produced by the furnace. The raw material is injected in the form of a "curtain", or "screen", into an upstream section of the furnace. This novel method and the novel device for carrying out said method allow the building-up of deposits upstream of the furnace to be eliminated.

Abstract: An improved method is disclosed for heat treating a preheated, pulverous raw material such as cement raw meal wherein a stream of oxygen containing gas is directed through a calcination chamber and the preheated raw meal and a calcining fuel are fed separately therein in a manner which provides mixing of the raw meal and the fuel and thereafter creates eddys of the mixture when it contacts the oxygen containing gas. The combined stream is directed out of the chamber and particles of raw meal are separated therefrom. A calcination plant is disclosed for practicing the method of the invention and a rotary kiln plant is disclosed for burning cement raw meal in a manner which includes at least partial calcination according to the inventive method.

Abstract: In the calcination of petroleum coke or the like in a rotary kiln, utilizing controlled air supply intermediate the ends of the kiln to burn removed volatiles and thereby generate all or nearly all of the heat required, highly effective control procedure includes establishing and repeatedly re-establishing target values for temperatures of exit gas and discharging product respectively at opposite ends of the kiln, such target temperatures representing conditions of desired position of the calcining zone and desired physical character of the calcined product which is achieved by proper maximum temperature in said zone. The procedure further includes adjusting one or more of the variables of combustion air supply, RPM of the kiln, and green coke feed rate so as to keep the end temperatures at target value.

Abstract: A method is disclosed for heat treating pulverous raw material such as cement raw meal prior to subjecting it to further heat treatment such as sintering. By directing the raw material to a multi-stage preheater having a final stage which comprises at least two substantially equivalent sub-stages and directing hot gases to the preheater in a manner to contact the raw material, an effective heat exchange between the raw material and the hot gases is achieved. The raw material is directed from the penultimate preheater stage so as to be entrained in the hot gases prior to directing the hot gases to the sub-stages of the final stage of the preheater and the hot gases and entrained raw material are divided into substantially equal divisional flows with each divisional flow being associated with a sub-stage of the final stage.

Abstract: The present invention provides an apparatus, and a method for the regeneration of spent wet active carbon, which apparatus comprises a drier for substantially drying the spent carbon, a heating furnace provided with at least one burner and at least one duct, and a regeneration chamber consisting of at least one set of inner cylinder and outer cylinder installed concentrically and vertically inside said heating furnace to penetrate the top and bottom walls of the furnace, wherein said inner and outer cylinders have respectively a multiplicity of holes penetrating the side walls thereof, said inner cylinder is connected with a supply tube for a regeneration gas capable of effecting regeneration of the dried carbon-to-be-regenerated upon contact therewith, the upper end of said outer cylinder is connected with said drier so as to receive said dried carbon therefrom while the lower end thereof forms an outlet for the regenerated carbon, and said duct is connected with the drier so as to facilitate direct or indir

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 stream of raw material is passed through a preheater to a furnace and a stream of exhaust gases from the furnace is passed through the preheater to preheat the raw material. Dust is electrostatically precipitated from the exhaust gases leaving the preheater, and the temperature of such exhaust gases is controllably raised to improve the efficiency of the dust removal by bypassing a controlled proportion of at least one of said streams around at least a portion of the preheater.

Abstract: An aqueous solution of magnesium chloride is sprayed into a kiln chamber where it is countercurrently heat treated by a stream of hot gas produced by flames projected into the chamber by burners. Calcined material is removed from the bottom of the kiln chamber and the hot gas stream and any treated material carried thereby is removed from the top of the chamber. Material carried by the hot gas stream is separated therefrom in a cyclone separator and the separated material is returned to the kiln chamber through a zone heated to a temperature in the range of the temperature in the kiln chamber.