Showing papers on "Rotary kiln published in 1972"

Method for the production of iron and steel

Abstract: Process for production of iron and steel. Although initial reduction is performed in rotary kiln or similar apparatus, products of excellent quality can be produced at lower cost than in processes based on blast furnace, irrespective of whether ore charged to kiln is of high or low gangue content and high or low in phosphorous and/or sulfur content. Moreover, improvements in economy of production are obtained even when ore is of low quality and final adjustment of composition to produce steel is carried out in direct arc electric furnace.

Rotary kiln for metal chip deoiling

Abstract: A rotary kiln in which oil and water can be removed from the metal chips in which a burner having outlets positioned throughout the length of the kiln introduces heat. The fuel to air ratio is adjusted such that no excess air is available in the kiln for combusting the oil coating on the chips. Thus the chips are subject to pyrolization in a reducing atmosphere, with the water and oil being vaporized and removed from the kiln along with the combustion exhaust gases.

Nozzle for rotary kiln

Abstract: A nozzle for use with a rotary kiln of the type used for reducing ore, such as iron ore, to a lower state of oxidation. The nozzle projects in a generally radial direction through the kiln shell to inject fluid into the interior of the rotary kiln. The nozzle comprises a gas passage for admitting a reductant gaseous fluid such as natural gas (methane) or an oxidizing fluid such as air into the kiln at appropriate times in the cycle of rotation of the kiln. The nozzle also includes a central oil tube slidably adjustably mounted in a sleeve which extends to the nozzle tip. The gas passage through the nozzle forms a hollow chamber around the sleeve in which the oil tube is enclosed, whereby the gas passing through the hollow chamber provides a cooling action on the oil tube and on the nozzle tip. The discharge outlet of the oil tube may be located within its enclosing sleeve in spaced relation to the nozzle tip, and in a cooler zone than the nozzle tip, whereby to minimize clogging of the oil tube discharge outlet by carbon deposits or the like. The central oil tube may be slidably moved within its enclosing sleeve to permit cleaning of carbon deposits from the nozzle tip. A quick disconnect coupling at the inlet end of the central oil tube permits disconnection of the oil supply to the oil tube while the kiln is rotating, permitting insertion of a cleaning rod in the oil passage of the central oil tube to "rod out" the central oil tube, the cleaning rod being extendible into cleaning engagement with the nozzle tip. The central oil tube may also be completely removed and replaced with another oil tube while the kiln is rotating.

Method of and apparatus for burning cement including atomizing dryer in cyclone preheater bypass

Abstract: In the manufacture of cement clinker from cement raw materials containing an undesirably high amount of alkalis, a rotary kiln having a preheater for the raw materials is employed. A portion of the effluent gases from the kiln is caused to bypass the preheater as a separate divisional flow. Water is atomized into this flow in such amounts that substantially all of the alkalis entrained therein in the form of solids, liquid or vapor are struck by the atomized fine drops of water. All of the water is vaporized in the hot flow of gas so that a substantial part of the alkalis is precipitated in the form of a fine dry powder, and the gas is simultaneously cooled.

Method and apparatus for heat treating with heat recuperation from material cooling and auxiliary heat during startup

Abstract: A method and apparatus is disclosed for heat treating mineral ore materials. The apparatus includes, in material series flow arrangement, a traveling grate preheater having at least one material drying zone and a preburn zone, a rotary kiln, and a cooler. The cooler has a first stage in which air becomes heated as the ore is cooled and this heated air is conducted through the kiln and preburning zones counter to material flow. The cooler has a second stage in which air is heated and thermal energy recuperated as the ore is further cooled and this second cooler stage air after being heated is conducted by a bypass conduit around the kiln and preburn zone to supply heat for drying the materials. An auxiliary air heater is associated with this bypass and according to the method disclosed, during start-up operation and before hot material arrives in the second stage of the cooler, the air heater is operated to heat the air conducted from the second stage of the cooler, for drying the material until hot material does arrive in the second stage of the cooler and thereafter heat transferred from the hot material to the air passing through the material in the second stage of the cooler, is utilized for drying the material. The disclosed apparatus operated according to the disclosed method, achieves improved fuel economy, more effective control of the drying or dehydrating operation, and such operation is achieved with a smaller kiln than heretofore required according to teachings of the prior art.

Apparatus for direct iron reduction

Abstract: In a direct iron reduction process of the type utilizing a rotary kiln, oxidizing gas is blown into the bed in the rotary kiln so as to increase the temperature of the bed and to increase the speed of movement of the gas in the bed.

Fluid delivery system for rotary kiln

Abstract: A rotary kiln is disclosed with a stationary hood mounted concentrically over the material feed end of the kiln. Fuel nozzles are mounted on the outer surface of the kiln shell and are connected to a manifold also mounted on the outer surface of the kiln shell. A fuel delivery tube connected to the manifold projects radially inwardly to the interior of the kiln and then axially outwardly through the hood to the exterior of the kiln for connection to the fuel supply. A cooling air pipe surrounds the portion of the fuel tube located in the interior of the kiln. Air is forced through the pipe to cool the fuel. A flexible ball joint is provided in the cooling pipe to compensate for any misalignment between the rotating axis of the kiln and the stationary axis of the hood.

Calcining process and installation

Abstract: A phosphate or like mineral material is calcined in a rotary kiln after having been dried and preheated to a temperature lower than the normal reaction temperature of the material. The preheated material is introduced into the hottest zone of the kiln and passed therethrough in the same direction as hot calcining gases. The calcined material is cooled with a current of fresh air, a portion of the cooling air is mixed with the gases removed from the kiln, and the gas mixture is used to preheat the material.

Pre-heating apparatus in rotary kiln plant

Abstract: Pre-heating Apparatus for pre-heating pulverous raw material (e.g. cement raw meal) prior to its introduction into a rotary kiln for burning is disclosed. In construction the pre-heating apparatus includes four strings of treating units, each unit including separation and heat exchange zones, wherein the units of each string are disposed in series superimposed relationship in communication with the kiln and wherein the four strings are arranged symmetrically with respect to determined planes oriented with respect to the kiln axis and kiln outlet.

Conveyor flights for rotary kiln

Abstract: A method for producing heat exchange between particles of raw materials and hot combustion gases in an inclined rotary kiln is disclosed. The kiln includes trough-shaped conveyor flights constructed to discharge the particles over the length of the kiln in the form of clouds of substantially parallel vertical curtains extending across the kiln at an acute angle to the axis of the kiln. The kiln can be used in a plant including means for collecting and returning the material carried out of the kiln.

Rotary kilns with uphill cooler tubes

Abstract: A rotary kiln equipped with specially constructed means for supporting the outlet ends of uphill cooler tubes independently of the kiln shell is disclosed. This support means includes a tubular body encircling the kiln shell in spaced apart relationship. The outlet ends of the cooler tubes are connected to this tubular body which itself is independently supported for rotation with the kiln shell.

Cooling of rotary furnace shell burner pipes and method

Abstract: Overheating of rotary kiln shell burner pipes has resulted in serious deterioration and severely limited service life in a number of operating furnace installations. Various measures have been applied in attempts to solve this problem, but with only limited success. This invention provides a positive solution by use of forced cooling employing an array of high-velocity air jets directed to impinge directly on the inner burner pipe walls. The apparatus includes an assembly of internal cooling header ducting within the burner pipe in an annular configuration, supplied with air under pressure, and equipped with an array of spaced jet nozzle openings through which cooling air jets are directed to impinge on the inner pipe surface, thereby effecting accelerated and continuous cooling of the burner pipe as it operates in the hot furnace atmosphere.

Apparatus for supplying air into combustion chamber of rotary kiln incinerator

Abstract: An inner drum extending axially through a cylindrical kiln is comprised of a hollow cylinder, and a hollow reinforcement structure closely fitted in the cylinder to prevent same from sagging at elevated temperatures. The reinforcement structure is cooled by the water flowing therethrough and may be substantially cruciform in cross section, dividing the interior of the cylinder into a plurality of air channels adapted to supply air into the kiln through a number of bores formed in the cylinder. The air channels are intercommunicated by a plurality of passageways extending through the reinforcement structure and/or by a hollow space formed at one or both ends of the cylinder in order to reduce fluctuations in the pressure or volume of air supplied thereto.

Plant for the treatment and the oxidation of antimony minerals

Abstract: Plant for the treatment and the oxidation of antimony minerals, wherein an antimony mineral with any granulometry and humidity, eventually crushed, is carried by a hot gaseous stream, subjected to milling, drying, subsequent separations and then introduced in a rotary kiln in a state of extreme subdivision and oxidized dispersed in a gaseous compressed oxidizing stream.

Cooler tubes for rotary kiln

Abstract: An improved cooler tube construction for rotary kilns is disclosed which includes a conical internal surface located at the inlet end of each cooler tube. This conical surface acts to prevent back-spill and to advance material through the cooler tube.

Apparatus for treating ores and other solid materials

Abstract: Particulate solid material, after preheating is tumbled in a somewhat downwardly inclined direction through an extended confined treatment zone while a current or stream of treating gas is pressed through the confined zone in the opposite direction. A current of heating gases at the proper temperature is passed upwardly through an extended confined zone to heat the material indirectly. The gas treated particulate material is discharged at a temperature below that at which it would react with atmospheric gases. The apparatus comprises a totally enclosed rotary kiln installation which maintains the solid material at a predetermined temperature by indirect heating means, and having arrangements at its opposite ends fo r the indirect preheating of the solid material prior to entering the kiln at one end, and for the indirect cooling of the material before the discharge thereof at the opposite end of the kiln.

Combustion disposal of manure wastes and utilization of the residue

Abstract: Agricultural manure wastes were combusted in a fluid-bed reactor or a small rotary kiln as a method for disposal of this waste material. As much as 90 percent weight reduction and 85 percent volume reduction was obtained by burning the manures. Dry manure burning in the fluid-bed reactor was self-sustaining, whereas wet manure was both dried and burned in the heated rotary kiln. Heat balance estimations indicated that preheating would be required to dry the wet manure prior to burning in the fluid-bed reactor. However, the estimation indicated that no extra heat was needed in the process if the wet manure was predried with exhausted combustion gases before being fed to the fluid bed. The burned residues were pelletized and found suitable for use both as a potassium and phosphorus fertilizer and as a lime soil conditioner.

Rotary kiln precooler construction

Abstract: A precooler for a rotary kiln comprises a hollow body having a flared inlet for connection to the discharge end of a rotary kiln, a cylindrical central portion of greater diameter than that of the kiln, and a tapered outlet having circumferentially spaced cooling tubes arranged on a circle having a diameter less than that of the central portion. The central portion preferably includes a liner having grooves extending between the inlet and the outlet.

Method for manufacturing cement clinker

Abstract: Method and apparatus is disclosed for manufacturing cement clinker in a rotary kiln system wherein the smoke gas velocity through the rotary kiln is advantageously increased to cause a quantity of pulverulent material to be entrained in the smoke gases which is significantly larger than heretofore considered desirable.

Processes for burning materials in rotary kilns and kiln plants for use therein

Abstract: 1,260,561 Rotary kilns F L SMIDTH & CO AS 30 June, 1970 [1 July, 1969], No 33128/69 Heading F4B In a rotary kiln for the burning of cement raw materials helical trough-shaped lifters 9 are provided over a length at least equal to five times the internal diameter of the kiln, these lifters being made of heat resistant metal and embedded in the conventional refractory lining 10 Passage of material down the kiln is slowed by individual barrier plates (20, Fig 4) for the lifters or by clam rings (12, Fig 2) encircling the inner periphery of the kiln A riser pipe 6 leads to a cyclone separator 7 with a feed pipe 8 leading back to the kiln, raw materials from a silo 5 being fed to this pipe 8 by pipe 5

Solids-to-solids heat exchange apparatus

Abstract: An inclined rotary kiln for direct-contact heat exchange between a coarse and a fine granular material. The coarse material travels downward through the kiln. The fine material is introduced near the lower end of the kiln and is transferred up the kiln stagewise via helical ducts in the kiln''s wall. Inlets to the ducts have grates which reject the coarse material but accept the fine material. The ducts extend helically upwardly relative the kiln and rearwardly relative kiln rotation so that the fine material is discharged from the ducts up the kiln.

Rotary kiln with a plurality of cooling pipes

Abstract: A rotary kiln construction, in which the kiln has one end connected to a funnel-shaped member the wider end of which is provided with a closure wall having a plurality of annularly arranged bores in which one end of a plurality of cooling pipes is mounted, the cooling pipes extending from the funnel-shaped member either in a direction away from the rotary kiln or in a direction toward the rotary kiln and around the same.