Abstract: A reaction furnace includes a rotating core within a heated shell, the core and shell defining an active annular zone. An interrupted helical screw carried by the core conveys material from an inlet at one end of the zone to an outlet at the opposite end of the zone. The furnace is operated with the annulus only partially filled. Volatiles rise to a void space at the top of the annulus and are drawn off.

Abstract: A system for disposing of solid waste which recovers a portion of the energy and materials value of the waste. The system includes a plurality of sealable containers for the solid waste, and a rotary kiln. An air cannon propels the containers into the vessel on a trajectory generally parallel to the axis of the vessel. The kiln is of the type including a cylindrical vessel containing materials to be processed therein. The vessel has first and second longitudinally opposite ends, and rotates about its longitudinal axis. A burner heats gases in the interior of the vessel for processing the material in the vessel. The temperature in the vessel progressively increases from the first end to the second end of the kiln.

Abstract: A continuous method of removing volatilizable organic composition from particulate mineral composition comprises heating the organic composition contaminated mineral particles in a rotating drum and exposing the particles to said hot gases to volatilize the organic composition from the mineral particles while advancing the particles counter-current to the direction of hot gas flow, removing a gaseous composition from the drum comprising a mixture of the gases of combustion, volatilized organic composition and airborne fine mineral particles, separating the fine mineral particles from the hot gases and volatile volatilized organic composition, returning the separated fine mineral particles into the drum near the hot end, mixing the fine particles with the coarse mineral particles advancing toward the hot drum end, continuing to heat the mixture of fine and coarse mineral particles until the concentration of volatilizable organic composition is less than about 100 parts per million, and recovering a mixture of

Abstract: Method for disposal of oily refinery sludges containing a hydrocarbon component, a solids component comprising sediments such as sand, silt, rust or scale, and water in an operating rotary kiln comprising a heated, rotating cylinder containing in-process mineral matter comprising analyzing the oily refinery sludge to determine its composition, drying the oily refinery sludge to a bulk granular material having an energy content of at least about 4,000 BTU per pound, and charging the dried bulk granular material to the rotary kiln and burning the bulk granular material therein.

Abstract: A method and apparatus for removing volatile organic contaminants from soil including removing contaminated soil from the earth; transporting and placing the contaminated soil into a soil hopper, the hopper being substantially sealed from the atmosphere to prevent fugitive emissions of the contaminants from escaping into the atmosphere; conveying the soil under sealed conditions into a heated vapor stripping conveyor having moving flights; conveying the soil under sealed conditions along the vapor stripping conveyor and in close contact with the flights to heat the soil to a temperature below the boiling temperatures of the contaminants, thereby causing moisture in the soil and the contaminants to be stripped from the soil; streaming non-oxidizing gases having a greater than ambient temperature across the surface of the soil to carry the contaminants and moisture across and away from the soil; and maintaining the rate of flow and temperature of the gases to prevent undue surface drying of the soil as the soil

Abstract: A method is shown for producing a lightweight aggregate by treating flyash and sewage sludge. The flyash and sewage sludge are mixed together and then agglomerated into pellets, with or without the use of a binder. The pellets may be coated and then are dried. The dried pellets are introduced into a rotary kiln in a direction that is co-current with the flow of fuel and air through the kiln. The pellets in the kiln witll be indurated and will experience complete calcination as well as varying degrees of pyrolizing and sintering. The product of the kiln is a nodular material having a low density but with a hard and porous structure. The product of the kiln is feed to a cooler. The flyash sewage sludge mixture has a significant fuel value that is usable in the kiln. Furthermore, the fuel value available in the kiln off-gases may be used for drying the materials.

Abstract: This invention isolates in separate furnaces the three thermochemical processes required in manufacturing Portland cement and sulphur dioxide from a calcium sulfate source so as to yield improved pyrometallurgical treatment for each individual process. Separating these processes facilitates selection of the most kinetically suitable reactions by enabling the maintenance of optimum conditions for each process without compromising the thermal or kinetic efficiencies of the other processes.Only one fourth of the calcium sulfate is reduced to calcium sulfide in a separate ad hoc reduction furnace specifically designed for achieving enhanced reduction parameters which results in minimized reduction equipment size. Treating most of the calcium sulfate elsewhere works to avoid side reactions and allows Portland cement raw mix components to have an enhanced synergistic catalytic effect on reduction kinetics.

Abstract: A fluidized bed system comprises at least three cells constituting a fluidized bed. One of the cells interposed between other cells may function as a non-fluidized bed cell in response to the operating condition of the system.

Abstract: A manifold (10) for use in a gas solder-reflow oven (50) comprises a hollow tube made from a transition metal having an open end (18) for receiving gas, a closed end (16), and a plurality of holes (12).

Abstract: The present invention is a regenerative gas incineration apparatus having three heat regenerators containing refractory heat exchange material. Gas is cycled through the regenerators first in one direction, then in another. The regenerators are each connected to combustion chamber having an air-fuel system and at least one burner. A system of valved ductwork is utilized to direct gas to be processed into and upwardly through a heating first regenerator into the combustion chamber, downwardly through a cooling second regenerator and exhausting the processed gas to the atmosphere. The temporarily idle third regenerator is purged of partially treated gas remaining from a previous cycle and this gas is directed to the combustion chamber. The flow of the gas through the system is periodically changed enable the heat recovered by cooling regenerator in the previous cycle to be used to heat incoming gas in the next.

Abstract: In a kiln plant for burning mineral raw materials, e.g. cement raw materials, by means of nitrogen containing, solid fuel, e.g. coal, and which plant comprises a kiln (1), a material cooler (2) coupled after the kiln and a multistring, multistage preheater (18-27 and 18'-27') mounted before the kiln, the one string, the kiln string (18-27), being in direct connection with the kiln riser pipe (8) and the second string, the calcining string (18'-27'), being connected to a separate calcinator (4) to which combustion air is supplied in the form of spent cooler air through an inlet (7), an NO.sub.x -reducing zone is established in the kiln riser pipe (8) and a part of the kiln string from an inlet (13) for nitrogen containing solid fuel of a fuel duct (10) and an inlet (12) of a branch-off (14) for the supply of spent cooler air. The length of the NO.sub.

Abstract: A method and furnace assembly for treating solid refuse. The refuse comprises both recoverable materials useful either in cement or in construction and contaminants. The contaminants have a vaporization temperature lower than the vaporization or sublimation temperatures of the recoverable materials. The furnace assembly comprises a resource recovery furnace connected to a cement manufacturing furnace. According to the method, the refuse is transferred through a resource recovery furnace. Inside the resource recovery furnace the refuse is separated into vaporized contaminants and recoverable materials. Gas carrying the vaporized contaminants is transferred to the cement manufacturing furnace and used as an energy source. The recoverable materials are used in the cement manufacturing furnace as a constituent for making cement.

Abstract: A process and apparatus are described for recycling dust generated in rotary kiln processes such as cement manufacture. The invention resides in enriching the atmosphere in the kiln with oxygen so as to increase the heat generated and accommodate the introduction of recycled kiln dust. The oxygen enrichment and dust recycle are balanced so that the kiln operates to produce the same quality product as it did without either oxygen enrichment or dust recycle.

Abstract: A process for thermal treatment of solid particles in a fluidized bed wherein the solid particles by thermal treatment form a lighter weight fraction and a heavier weight fraction, relative to the total contents of the bed. The process is characterized by use of a selective heavier particle discharge conduit in the sloping bed support and maintenance of a discrete fluid fueled flame in close proximity to and above the opening to the heavier particle discharge conduit. This forms a higher temperature zone in and surrounding the flame, at least about 100.degree. F. higher than the remainder bed temperature. Circulation of solid particles through the flame and its surrounding higher temperature region is promoted both by directing of fluidization gas jets in the fluidized bed support and by the jetting action of the upwardly flowing heavier particle discharge gas.

Abstract: A cement clinker-producing plant has a suspension preheater (1,2,3), a calciner (4) united with a stationary reactor (6) and coolers (7,8). Air is blown up through the cooler (7) into the reactor (6) where a spouted bed, in which the clinker is burnt, is produced. The air flow is controlled so that only clinker particles which have grown to a certain size can fall through the air flow into the cooler (7).

Abstract: A kiln for reclaiming quick lime for calcium carbonate sludge formed in the production of cooking liquors in a wood pulping process for the production of paper. The kiln provides increased output with lower energy input due to: measurement and control of oxygen content in the kiln; non-air mixing burner; castable refractory liner with tumbler ribs; a heat transferring chain system; and a variable speed exhaust fan and air flow control. The output of the kiln was increased by more than ten percent along with a forty-five percent improvement in energy efficiency at substantial cost reduction due to its efficient use of energy.

Abstract: A method and apparatus of cofiring hazardous organic waste in solid, pasty, greasy or sludge form by introducing it directly into the burning zone of an industrial rotary kiln and burning the waste in the burning zone simultaneously with cement, lime or lightweight aggregate. Specifically disclosed are five exemplary embodiments for introducing the waste directly into the burning zone of the kiln, i.e., (1) through a side opening in the kiln, (2) ballistically, (3) by pre-mixing with a powder or granular material and pneumatically injecting the non-sticky mixture, (4) by shredding steel drums containing the waste and thereafter separating the drum fragments and mixing the remaining waste with powder or granular material (i.e. as in (3) and (5) by pregasification of the waste.

Abstract: Process and furnace for producing clinkered cement pellets from pellets of cement-forming batch materials without melting, fusion and agglomeration of said pellets. The furnace comprises an elongate vertical suspension shaft having top, intermediate and bottom portions. Pellets are fed at the top and heated to calcining temperatures before exiting the shaft into a pre-clinkering zone beyond the bottom. The pellets are heated to pre-clinkering temperatures and deposited on a porous pellet bed through which cooling air is forced to control the exothermic clinkering reaction and to regulate the speed at which the pellets migrate through the shaft.

Abstract: A thermal treatment process employs an indirectly fired rotary kiln in which matrix material contaminated with organic substances such as dioxins, PCBs, PAHs, fuel oils, and the like is heated as the material is advanced through the kiln to cause components of the organics to be released as vapor. Purge gas of low oxygen content is conducted through the kiln at a relatively low velocity of from about 0.5 ft./sec. to about 10 ft./sec. to gently sweep the vaporized components of the organic substances from the kiln and to minimize the entrainment of solid particulates, and to produce an off gas mixture including the vaporized components. The off gas is conditioned after removal from the kiln to render it acceptable for discharge to the atmosphere. The oxygen concentration in the kiln is maintained at a sufficiently low level to substantially prevent combustion of the vaporized organic components in the kiln.

Abstract: A continuous method of removing volatilizable organic composition from particulate mineral composition comprises heating the organic composition contaminated mineral particles in a rotating drum and exposing the particles to said hot gases to volatilize the organic composition from the mineral particles while advancing the particles counter-current to the direction of hot gas flow, removing a gaseous composition from the drum comprising a mixture of the gases of combustion, volatilized organic composition and airborne fine mineral particlles, separating the fine mineral particles from the hot gases and volatile volatilized organic composition, returning the separated fine mineral particles into the drum near the hot end, mixing the fine particles with the coarse mineral particles advancing toward the hot drum end, continuing to heat the mixture of fine and coarse mineral particles until the concentration of volatilizable organic composition is less than about 100 parts per million, and recovering a mixture of

Abstract: A method for the heat treatment of finely granular material, particularly for the manufacture of cement, employs a preferably multi-stage cyclone preheater (2), a rotary tubular kiln (1), a cooler (6) and a kiln off-gas line (5) which is formed between rotary tubular kiln (1) and cyclone preheater (2). The off-gas lines provides a passage substantially in upward direction for the off-gases of the rotary tubular kiln (1) and receives tertiary air fed thereto for the combustion of additional fuel. The tertiary air is provided in two streams from the cooler (6), which cooler is connected behind the rotary tubular (1) on the material side, the streams being introduced into the kiln off-gas line (5) at different heights. In order to separate the combustion of the additional fuel from the precalcination and to avoid the production of injurious nitrogen oxides (NO.sub.

Abstract: The present invention provides an energy conserving process for calcining a clay and apparatus for carrying out the process. A dry pulverized clay powder (1) is fed to a calciner (20) to be calcined therein. The calcined clay product (3) is removed from the calciner (20) and preferably passed in heat exchange relationship with a cooling medium (71) whereby the calcined clay product (3) is cooled and the cooling medium is heated. The hot off-gas (7) discharged from the calciner (20) is passed through an electrostatic precipitator (30) to remove at least a substantial portion of calcined clay product dust (11) entrained in the exhaust gas from the calciner. The clean gas (13) leaving the electrostatic precipitator (30) is passed in heat exchange relationship with a cooling fluid (51) to further cool the gas, and preferably to evaporate at least a portion of the cooling portion to produce a heating vapor (53).

Abstract: The invention relates to a method and to apparatus for the heat treatment of fine-grained material using a calcination zone which is arranged between a preheating zone and a final combustion zone, and after passing through the calcination zone a proportion of the material is introduced into exhaust air from the cooling zone and delivered therewith back to the calcination zone for the purpose of recirculation. In this way a good burn-out of the fuel used in the calcination zone and a high degree of deacidification of the material are achieved.

Abstract: In a method of thermal treatment of particles, the particles are blown into a hot gas stream by means of a reactor blower. In a circle around a fuel jet and through an entry opening the particles are blown through a diffuser into the bottom of a vertically oriented cylindrical reactor chamber of a suspended gas rector. They are passed through an exit opening at the top of the reactor chamber. During this process the fuel gas stream, which is produced by a burner and is directed into the reactor chamber, forms a convective stream with the particles located therein. Particles that exceed a certain predetermined maximum size are fed into a part of the reactor chamber that is above the diffuser.

Abstract: A method for the heat treatment of finely granular material, particularly for the production of cement, employs a multi-stage cyclone preheater, a rotary tubular kiln, a cooler, and a single kiln off-gas line which is formed between the rotary tubular kiln and the cyclone preheater and is flown through substantially in upward direction by the off-gasses of the rotary kiln and to which tertiary air is fed in two partial-streams for the combustion of additional fuel. The method employs steps of feeding fuel to a lower partial stream of tertiary air, directing material to be treated above a second partial stream of tertiary air, and applying precalcined material in countercurrent with the off-gas line below the tertiary air.

Abstract: The invention concerns an improved method of calcining gypsum in which non-reactive hot gas is passed into contact with the gypsum from a source through a plurality of tubes extending downwardly into the gypsum. The invention also contemplates an improved apparatus which comprises a calcining kettle and a plurality of tubes connected to a common source of non-reactive hot gas and extending downwardly into the kettle and having openings in their lower regions to release the hot gas into the contents of the kettle. The invention provides a method and apparatus which produces gypsum plaster of improved quality and with less insoluble anhydrite.

Abstract: A drum mixer having an countercurrent flow drying zone and a parallel flow mixing zone is provided for producing an asphaltic composition. The drum mixer utilizes a heat source located at an intermediate position therein for generating three streams of hot gases. The first stream of hot gases is directed towards the receiving end of the drum mixer in a countercurrent direction to the flow virgin aggregate entering the drying zone of the drum mixer. Recycle material is introduced into the drum mixer between the heat source and the discharge end thereof. The recycle material and the heated virgin aggregate are combined within the mixing zone. As both materials travel towards the discharge end of the drum mixer the second stream of hot gases is directed towards the discharge end of the drum mixer in a parallel direction to the flow of the mixing materials for heating said materials.

Abstract: A process for enhancing heat transfer between combustion products formed in a fluidized bed combustion (FBC) reactor and the water-containing tubes surrounding the reactor wherein particles of an inert material, e.g., mineral calcium sulfate (gypsum), having a spheroidal shape ranging in size from about 50 to 1000 .mu.m and having a Moh's hardness of between 2.0 and 4.0 are introduced into the reactor in the presence of a solid fuel and an oxygen-containing gas. Introduction of such particles into the FBC reactor increases the particle density within the reactor thereby increasing radiant and convective heat transfer between the circulating bed and the surrounding water cooled walls. The improved process allows more precise control of the operating temperature regime. Erosion of the reactor walls is also substantially reduced.

Abstract: A method and apparatus for the manufacture of cement from raw cement meal wherein the meal passes through a series of preheating cyclones, through a calcining zone, through a rotary sintering furnace and to a cooler with the flow of meal from a penultimate cyclone heat exchanger divided into subflows with one chamber receiving air from the cooler and also receiving burning fuels that are extremely difficult to burn and both calcining chambers delivering meal to the last heat exchanger for delivery to the furnace.

Abstract: A shaft kiln installation is used to burn pellets of solid materials containing volatile and/or solid fuels and at the same time to calcinate minerals. For this purpose, the installation uses in the heating, degassing (1,04) and combustion zones (1,06) a co-current flow of combustion gas. The installation has at least one first upper section (1,04;1,06) for carrying out the above-mentioned process steps. If necessary, a third counter-current cooling section (1,10) for the combustion material and a second, midddle section (1.08) that acts as a neutral zone, may be added. The heat content of the combustion gas and cooling air may be used for heating the combustion air.

Abstract: The invention relates to apparatus and to a method for the heat treatment of fine-grained material using a multi-stage cyclone preheater and a combustion chamber supplied with tertiary air from the cooler, in which the branched part of the tertiary air pipe extends upwards and the material discharged from the second-lowest stage of the cyclone preheater is introduced into one branch pipe at a point which lies lower than the point at which this branch pipe is connected to the combustion chamber. In this way good dispersal of the material which is delivered pneumatically to the combusion chamber and excellent combustion conditions are achieved at the same time as a considerable reduction in the overall height of the entire cyclone preheater.

Abstract: A rotary kiln device for incinerating combustible materials such as municipal and commercial waste materials. The kiln is a co-current gas-material flow apparatus. The kiln is divided by means of a dam into a drying zone and a combustible zone. Waste material is retained within the drying zone sufficiently long so that that moisture contained in the material is driven off. Air for combustion is supplied directly to the combustion zone, bypassing the drying zone so that self-sustaining combustion may take place.

Abstract: The present invention relates to a novel process and to an installation for performing the process for calcining limestone for producing lime of different qualities, while being able to entirely or at least substantially do without conventional energy carriers such as coal, oil and natural gas. Instead waste energy carriers of different origins are used. According to the process the waste energy substances are firstly gasified in a suitable gasifier, which is constructed as a shaft reactor or fluidized bed reactor and at elevated temperature, the dust being then removed from the lean gas produced and subsequently passed into the combustion chambers of the gasification reactor where burning takes place. The pollutants in the waste energy carriers are destroyed or rendered harmless by the high temperature of approximately 1600.degree. C. in the gasification reactor. Dust and harmful components are then deposited in the coke filling or in the dust catchers.

Abstract: For the production of a product which can be dumped or utilized, the mineral substances are subjected in a rotary kiln to a thermal treatment at a temperature at which the charge of the rotary kiln is transformed to a pasty to liquid slag phase. The composition of the charge is so selected that a slag phase is produced in which the main components, which constitute a matrix, are in the range from 60 to 72% SiO.sub.2, 10 to 30% Al.sub.2 O.sub.3 and 5 to 25% CaO+MgO, of said matrix, wherein the total percentage of SiO.sub.2 +Al.sub.2 O.sub.3 +CaO+MgO equals 100, the total of the main components SiO.sub.2, Al.sub.2 O.sub.3, CaO and MgO amounts to more than 60% on a dry and ignition loss-free basis, of the mineral matter which is charged to the rotary kiln. The slag phase discharged from the rotary kiln is cooled and the exhaust gas from the rotary kiln is purified.

Abstract: Apparatus, and a method for using the apparatus, for detoxifying material contaminated with at least one volatile organic compound (VOC). The apparatus is provided with a dryer having a heat source to heat the VOC-contaminated material to a first temperature, hot enough to volatilize the VOC, but below the cracking temperature of the VOC. The VOC in the dryer is volatilized to form VOC gases. A kiln heats the VOC gases with excess air to a second temperature, hot enough to destroy the organics in the VOC gases. Simultaneously the kiln is used to treat a kiln processable material to form a desired product. The kiln includes means for feeding the kiln processable material to the heating chamber, means for cooling and recovering the desired product, and means for providing heat for the VOC dryer. The apparatus also includes a conduit for conducting the gases containing VOC from the dryer to the kiln.

Abstract: The invention relates to apparatus for the heat treatment of fine-grained material having a rotary drum furnace, a preheater, a cooler, and a combustion chamber for precalcination of the material. Exhaust air from the cooler is delivered on the one hand to the combustion chamber and on the other hand via two pipes directly to the furnace exhaust gas pipe, and connections for the supply of fuel and preheated material are provided in these latter pipes shortly upstream from the point at which they open into the furnace exhaust gas pipe.

Abstract: Fine particulate solid fuel is utilized in the calcining or uniflow shaft of a uniflow regenerative shaft furnace having outlet openings of fuel lances of the furnace arranged with a uniform distribution over the cross-section of the furnace shaft in a horizontal plane between the preheating zone and the calcining zone of the furnace. The fuel feed is maintained constant with time by a dosing system through which fuel is supplied through feed lines to the fuel lances. Due to the uniform distribution of solid fuel which is accomplished, a calcined material is obtained which has a quality comparable to that which may be achieved through calcining with gaseous or liquid hydrocarbons.

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 method for utilizing the heat energy of domestic and commercial refuse in a rotary kiln installation. The prepared crude refuse is degassed in a pyrolysis reactor and the pyrolysis gas produced is delivered to the main burner of the rotary kiln, optionally using primary fuel. For optimum and economic production of the pyrolysis gas crushed refuse is dried pneumatically with the aid of exhaust air from the cooler and is delivered to the pyrolysis reactor. The pyrolysis reactor is heated indirectly to a low temperature with hot secondary air from the kiln outlet head and the pyrolysis gas produced is delivered together with used secondary air to the main burner of the kiln.

Abstract: A drum mixer asphalt plant is provided with a rotatable cylinder 10 in which virgin aggregate, recycle material and liquid asphalt are mixed to produce an asphaltic composition and the hot gas stream for heating and drying the materials flow in countercurrent relation. In a first zone within the cylinder 10, aggregates are heated and dried by heat radiation and a hot gas stream generated at a burner head 46 of a combustion assembly 40. In a second zone within the drum cylinder 10 isolated from the burner flame and hot gas stream by the combustion assembly 40, liquid asphalt is sprayed from an injection tube 76 to mix with aggregate materials. A recycle feed assembly 60 delivers recycle asphalt material to the second zone also for mixing with the aggregate and liquid asphalt.

Abstract: A liquid fuel fired apparatus and method for the efficient distribution and utilization of heat in the melting of a particulate feedstock. The feedstock is preheated to an incipient softening point temperature in a vertically disposed shaft. The column of feedstock in the shaft is supported on the top of a freestanding pile of feedstock disposed on the floor of a surrounding melting chamber having downwardly diverging sidewalls. Liquid fuel burners direct hot combustion products towards and around the base and intermediate portions of the feedstock pile causing the outside of the pile to be melted. Gas at a temperature below the softening point temperature of the feedstock is introduced around the top of the pile to prevent the hot gases in the lower portion of the melting chamber from prematurely melting the feedstock.

Abstract: A vertical shaft kiln utilized in calcining limestone defines a series of processing zones including an upper preheating zone, a first calcining zone, a second calcining zone having a length twice that of the first calcining zone and a material cooling zone, Burners inject burnt gases intermediate the two calcining zones. Major heat transfer to the limestone is accomplished in the first calcining zone by directing a major portion of the burnt gases in counter-current to the material flow therethrough. Minor heat transfer is accomplished in the second calcining zone by directing a minor portion of the burnt gases therethrough in co-current relation with the material. Combustion air is provided through ducts in the material cooling zones and mixed with the minor portion of burnt gases externally of the shaft prior to injection into the burners.

Abstract: A method and apparatus for the thermal treatment of pulverulent raw material in the manufacture of cement clinker including passing raw material first through a multi-stage preheating treatment including cyclones arranged following one another, next passing the material through a reaction stack for calcination, then passing the material through a sintering kiln and thereafter through a clinker cooler, the exhaust air from the clinker cooler and the exhaust gas from the sintering kiln being passed parallel to the each other with the material discharged into conduits respectively carrying the discharged clinker cooler air and the sintering gases with burners in the conduits and the gases thereafter passing up through the reaction stack and then through a separator and into the sintering kiln.

Abstract: A method and apparatus for calcining limestone to produce lime wherein coal is combusted to provide heat for the calcination. The coal is combusted in a two stage combustion unit, with at least seventy-five percent of the slag formed by the coal combustion removed from the first stage of the combustion unit. Residual gases and fuel are further combusted in the second stage of the two stage combustor, with hot combustion gases therefrom, having the molten slag removed, fed directly to the calcining chamber of a rotary lime kiln. The coal may be carbonized to form a char and a fuel gas for use in the two stage combustor.

Abstract: A method for calcining carbonaceous materials in a rotary kiln is disclosed. An oxygen injection lance provides oxygen through the wall of a firing hood and into the carbonaceous bed, which is at an elevated temperature. The oxygen burns a portion of the carbonaceous material, providing the necessary heat for calcining the remainder of the carbonaceous materials in the kiln.

Abstract: Solid materials are efficiently calcined in a single column kiln by effecting said calcination through a plurality of vertically arranged zones, by means of a method comprising the steps of feeding said solid materials to a preheating zone wherein the materials are preheated countercurrently with combustion gases, allowing said preheated materials to fall to an air preheating zone to which primary air is fed in parallel flow with said falling preheated materials, allowing said materials to fall to a calcining zone to which fuel is admitted in parallel flow with said preheated air, allowing the thus calcined materials to fall to a cooling zone to which secondary cold air is fed countercurrently with said falling materials, exhausting the combustion gases produced in the calcining zone together with said secondary air which was preheated by the calcined materials, at a point between said calcining and cooling zones, and feeding said combustion gases and secondary air as a mixture to the preheating zone.

Abstract: An oven is described which is especially adapted to maintain accurate and uniform temperature control. The device of the invention includes a central treatment chamber surrounded by a plenum chamber which, through a number of spaced apart apertures introduces gases at a preselected temperature and elevated pressure into the treatment chamber. The plenum chamber is configured to insure a substantially uniform pressure at each of the apertures to provide a uniform flow of temperature regulated gases through each of the apertures.

Abstract: There is disclosed a process for producing dried and cleaned metal chips by entraining metal chips in a gas, introducing the gas into a cyclone separator having a wall heated to fluid-vaporizing temperature by combustion effected in a surrounding chamber, purging fluid from said chips, exhausting hot gases and exiting dried metal chips from said separator, conducting hot gaseous products of combustion from the combustion chamber to a continuous centrifuge, extracting extractable fluid from starting metal chips, which may be previously uncleaned and/or unwashed, in the centrifuge, entraining the chips in the hot gaseous products of combustion introduced into the centrifuge, and conducting the gaseous products with entrained chips from the continuous centrifuge to the cyclone separator, thereby providing an essentially closed system.

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: According to the present invention, white cement clinker particles are not burned in a rotary kiln and the burned clinker particles are not immersed in the water to be cooled. White cement clinker raw materials are burned in a fluidized bed burning furnace with a fluid bed or a spouted bed and the clinker particles thus burned are reduced with a reducing gas. The clinker particles thus reduced are first cooled with the water which is sprayed over the clinker particles and then further cooled with the air. The white cement clinker raw material particles fed into the fluidized bed burning furnace are burned into clinker particles while forming a fluidized bed and then the clinker particles thus burned drop through a jet injection pipe into a reduction chamber disposed below the burning furnace and are reduced. The clinker particles thus reduced are rapidly cooled to 600.degree.-700.degree. C.