Showing papers on "Rotary kiln published in 2001"
TL;DR: Results up to 28 days showed that these synthetic aggregates were capable of producing concretes with compressive strengths ranging from 33 to 51 MPa, equivalent to between 73 and 112% of that of the control concrete made with natural aggregates.
88 citations
TL;DR: In this article, a one-dimensional mathematical model was developed for the simulation of petroleum coke calcination in rotary kilns, which is comprised of 14 ordinary differential equations derived from mass and energy conservation principles.
59 citations
Patent•
17 Dec 2001
TL;DR: In this paper, a rotary kiln for the thermal treatment of scrap material is described, where a reaction zone (10, 10a, 10b, 10c) is formed by a reaction kiln having the longitudinal axis inclined of an angle in the range 0° ± 45° with regard to an horizontal plane.
Abstract: The plant for the thermal treatment of material, in particular scrap material, comprises at least a reaction zone (10, 10a, 10b, 10c) within a rotary kiln (12) having the longitudinal axis inclined of an angle in the range 0° ± 45° with regard to an horizontal plane and provided of first heating means (14) and of at least a rotary screw (16) having second heating means (18). The screw shaft (20) is hollow and has, at least locally, apertures allowing the flow of gas from and/or into the reaction zone (10, 10a, 10b, 10c), a plurality of thermally conductive particles being movable within the reaction zone (10, 10a, 10b, 10c).
49 citations
Patent•
10 Jul 2001TL;DR: In this article, a process for removing mercury and organic compounds from gaseous stream using an adsorption powder, characterized as containing a carbon-based powder and an effective amount of cupric chloride, is described.
Abstract: A process for removing mercury and organic compounds from gaseous stream using an adsorption powder, characterized as containing a carbon-based powder and an effective amount of cupric chloride, the process characterized by the steps of: a) placing a solid phase mercury-containing contaminated soil into a rotary kiln/drum; b) heating the kiln/drum to form gaseous and solid components of the soil; c) transferring the gaseous component to an exhaust cleaning unit/afterburner, and transferring the soil component to a cooling unit; d) heating the gaseous component in the exhaust cleaning unit/afterburner; e) cooling the gaseous component; f) adding the adsorption powder to the gaseous component; g) transferring the powder-containing, gaseous component to a baghouse; and h) releasing the substantially mercury-free gaseous component to the atmosphere.
39 citations
TL;DR: In this paper, cold bonded ore-coal composite pellets developed on a laboratory scale were tested in a rotary kiln sponge iron plant, which achieved more than 90% metallisation of sponge iron using OCC composite pellets.
Abstract: Cold bonded ore–coal composite pellets developed on a laboratory scale (Part 1 of this two part paper) were tested in a rotary kiln sponge iron plant. This plant had a 12 m length refractory lined rotary kiln of 8 t/day iron ore throughput capacity. Kiln operation was optimised to achieve more than 90% metallisation of sponge iron using ore–coal composite pellets. The kiln productivity increased and energy consumption decreased, compared with levels obtained when sized lump ore was used as iron oxide feed material. The plant trials established the suitability of composite pellets for sponge ironmaking with enhanced kiln productivity.
30 citations
Patent•
05 Feb 2001
TL;DR: The co-combustion process may include the following unit operations: routing of hot gas generated in the clinker cooling process to a rotary kiln, use of part of the kiln exhaust gas to dry solid wastes in rotary dryers, leading the gases from both the dryer and the combustion kiln to the secondary combustion chamber, and use of additional fuel to boost up the secondary chamber reaction temperature to as high as 1200° C as mentioned in this paper.
Abstract: The co-combustion process may comprise the following unit operations: routing of hot gas ( 10 ) generated in the clinker cooling process to a rotary kiln ( 1 ); use of part of the rotary kiln exhaust gas to dry solid wastes in rotary dryers; leading the gases from both the dryer and the combustion kiln to the secondary combustion chamber ( 2 ); use of additional fuel to boost up the secondary combustion chamber reaction temperature to as high as 1200° C.; primary dry gas scrubbing in a precalciner or precalciners ( 3, 3 a ); heat recovery ( 4 ) and power generation; secondary gas scrubbing ( 5 ) in a semi-dry scrubber; bag filtering after activated carbon injection and returning of all the collected ash and used carbon into the waste kiln and/or a cement kiln. Detrimental materials for cement processing generated by waste combustion can be by-passed to a scrubbing system and a cement kiln. Residue slag from waste kilns can be treated and reused.
25 citations
TL;DR: In this paper, the feasibility of solar thermal remelting of aluminum scrap was constructed for experimentation in a mini-plant scale in the DLR high flux solar furnace, and pre-designs both for solar pilot and industrial scale applications were presented.
Abstract: To check the feasibility of solar thermal remelting of aluminum scrap a directly absorbing rotary kiln receiver-reactor was constructed for experimentation in a mini-plant scale in the DLR high flux solar furnace. Conventionally the high energy demand for heating rotary kilns is met by the combustion of fossil fuels. This procedure generates a big exhaust gas volume which is contaminated by volatiles if the technology is applied to treat waste materials. Application of concentrated solar radiation to provide the high temperature heat enables to substitute the fossil fuel. Thus smaller off-gas streams are generated and lower investment and O&M cost are expected for the off-gas purification. In this paper market and environmental issues are discussed and pre-designs both for solar pilot and industrial scale applications are presented.
24 citations
TL;DR: In this paper, a rotary kiln used to produce cement clinker is simulated, including exothermal reactions into the clicker and advanced heat transfer correlations, and the impact of oxygen enrichment on the kiln operation is assessed.
Abstract: This work presents the simulation of a rotary kiln used to produce cement clinker. The effort uses an original approach to kiln operation modeling. Thus, the moving cement clinker is accurately simulated, including exothermal reactions into the clicker and advanced heat transfer correlations. The simulation includes the normal operation of a cement kiln, using coal in an air-fired configuration. The results show the flame characteristics, fluid flow, clinker and refractory characteristics. Two types of coal are employed, one with medium-volatile and one with low-volatile content, with significant differences noted in the kiln operation. A specific goal of this effort is to study the impact of oxygen enrichment on the kiln operation. For this purpose, oxygen is lanced into the kiln at a location between the load and the main burner, and the impact of oxygen enrichment on the kiln operation is assessed. Different oxygen injection schemes are also studied. Thus, varying the angle of the oxygen lance enables ...
20 citations
DOI•
01 Jun 2001
TL;DR: In this paper, the authors described the process technology of the production of rice hush ash (RHA) as a supplementary cementing material, and a new stirring type furnace was introduced for the production RHA with large specific surface area.
Abstract: This paper describes the process technology of the production of rice hush ash (RHA) as a supplementary cementing material. The incinerating tests of rice husks were carried out by changing the temperature and duration of incineration using a rotary kiln. From the incineration tests, it was concluded that the incinerating temperature should be lower than 50 m2/g, and the duration of incineration should be long enough to obtain RHA with ignition loss less than 3%. Based on the incineration test results with the rotary kiln, a new stirring type furnace is introduced in the present paper for the production of RHA with large specific surface area. An applicability of the stirring furnace is examined by changing the feeding rate of rice husks and rotation speed of stirrer. The RHA having specific surface area larger than 50 m2/g and ignition loss less than 3%, can be produced using the new stirring furnace at a temperature below 500 degrees C. Using this high specific surface RHA, strength development properties of mortar were examined and compared to the mortar incorporating a lower specific surface RHA and silica fume. The compressive strength of mortar incorporating the high specific surface RHA was increased remarkably, and was higher than that of the lower specific surface RHA and silica fume. Furthermore, unlike other pozzolanic materials, mortar incorporating the higher specific surface RHA showed excellent early strength development.
19 citations
Patent•
14 Feb 2001
TL;DR: A process for preparing the Ti-enriched material from ilmenite concentrate includes grinding and magnetic separation to obtain Ti-enhanced material and powdered iron concentrate in rotary kiln and direct reducing at 1100-1150 deg.C as mentioned in this paper.
Abstract: A process for preparing the Ti-enriched material from ilmenite concentrate includes grinding ilmenite concentrate, mixing it wich additive and adhesive, sphericizing, solidifying, direct reducing at 1100-1150 deg.C in rotary kiln, grinding and magnetic separation to obtain Ti-enriched material and powdered iron concentrate. Its advantages include lower reducing temp lowered by 130-220 deg.C, highacidolysis performance of Ti-enriched material, high grade of TiO2 and high recovery rate of Fe and TiO2 increased by 20% and 5% respectively.
16 citations
Patent•
19 Jan 2001
TL;DR: In this paper, a rotary kiln cylindrical burner is provided with a group of inside primary air injection holes 13b disposed on a concentric circle and partitioned from each other.
Abstract: PROBLEM TO BE SOLVED: To provide a rotary kiln combustion apparatus and a combustion method useable without deteriorating the quality of an article calcined in a rotary kiln without pulverizing combustible solid particulate substance. SOLUTION: In a rotary kiln cylindrical burner there are provided a group of inside primary air injection hole 13b disposed on a concentric circle and partitioned from each other, a group of fuel/conveyance air mixture injection holes 14b, and a group of inside primary air injection holes 15b. Further, one combustible solid particulate fuel injection hole 16a is disposed inside the injection holes 15b, and primary air and a fuel are combusted through the injection holes to form a flame highest temperature region while feeding the secondary air into the rotary kiln. The particulate fuel injected from the injection hole 16a is passed through the region into combustible gas which is then combusted.
TL;DR: In this paper, the results of studies concerned with mechanical effects on the lining of rotary kilns are reviewed, and the effects of calcined material on the linings are discussed.
Abstract: Results of studies concerned with mechanical effects on the lining of cement rotary kilns are reviewed. Stresses arising from strains of the kiln casing and from slippage of the lining against the kiln casing are considered, and mechanical effects exerted by the calcined material on the lining are discussed.
Patent•
12 Sep 2001
TL;DR: In this article, a method for steel making using a direct reduction reactor (DRR) with iron ore from a charging system is described. And a mini-mill is used to perform the method of steel making.
Abstract: Disclosed is a method for steel making which includes charging a direct reduction reactor (DRR) with iron ore from a charging system. The iron ore is reduced to hot direct reduced iron (DRI) in the DRR and discharged to rotary kiln(s). The rotary kiln(s) does not process the DRI, but transports the hot DRI to one or more electric arc furnaces (EAF). Top gas (i.e., spent reducing gas) is drawn off of a top section of the DRR. A portion of the top gas is used to pressurize the rotary kiln to prevent air from entering the rotary kiln. Another portion of the top gas flows to a pressure swing adsorber or a vacuum pressure swing adsorber (PSA/VPSA) for CO2 and H2O removal. A cool reducing gas exits the PSA/VPSA. A plasma torch burns natural gas and oxygen to form a hot reducing gas. The hot reducing gas is mixed with the cool reducing gas to form a final reducing gas. The final reducing gas is delivered to the DRR. Also disclosed is a mini-mill to perform the method of steel making.
Patent•
20 Feb 2001
TL;DR: In this article, a rotary kiln was used to remove zinc from zinc-containing iron oxide in a shorter time than that in the conventional method and the pro ductivity can be improved.
Abstract: PROBLEM TO BE SOLVED: To provide a method for removing zinc in zinc-containing iron oxide using a rotary kiln with which the formation of a ring is prevented and solid- reduction of iron oxide is performed by separating zinc from the zinc-containing iron oxide in a shorter time than that in the conventional method and the pro ductivity can be improved. SOLUTION: In the method for removing zinc in the zinc-containing iron oxide using the rotary kiln 12, with which the zinc-containing iron oxide is heated in the furnace 24 of the rotary kiln 12 and the zinc is separated from the zinc-containing iron oxide and further, the iron oxide is reduced to obtain the iron-containing material 25, mixture raw material 11 consisting essentially of the zinc-containing iron oxide and a carbonaceous material for reducing zinc oxide in the zinc-containing iron oxide and the iron oxide is manufactured. The mixture raw material 11 is charged into the furnace 24 of the rotary kiln 12 having ≥1,100°C atmospheric temperature in the furnace and the zinc oxide in the zinc-containing iron oxide is reduced with the carbonaceous material and further, vaporized to obtain the iron-containing material 25 chargeable into a reduction furnace. COPYRIGHT: (C)2002,JPO
Patent•
29 Jun 2001
TL;DR: A rotary kiln for calcination of light aggregate cement comprises a calcination kiln body, a heavy-oil combustion device, and a cooling device, wherein the calcination Kiln body is formed in a U-turn for saving construction site and is composed of a feeding entrance at its upmost end, a product exit at the lowest end and a plurality of revolving segments varied in caliber by segment as discussed by the authors.
Abstract: A rotary kiln for calcination of light aggregate cement comprises a calcination kiln body, a heavy-oil combustion device, and a cooling device, wherein the calcination kiln body is formed in a U-turn for saving construction site and is composed of a feeding entrance at its upmost end, a product exit at the lowest end, and a plurality of revolving segments varied in caliber by segment so as to raise the calcination efficiency, save construction expenditure, and meet environment requirements.
Patent•
15 Aug 2001
TL;DR: In this paper, a system for the manufacture of cement clinker from cement raw meal is described, in which the off-gases of the clinker production line not only undergo denitrification but also undergo desulfurization, so that even sulfur rich raw materials and fuels can be employed without exceeding the prevailing pollutant emission limits.
Abstract: A system for the manufacture of cement clinker from cement raw meal in which the off-gases of the cement clinker production line not only undergo denitrification but also undergo desulfurization, so that even sulfur-rich raw materials and fuels can be employed without exceeding the prevailing pollutant emission limits A substream of the oversize material (30) discharged from the mixing chamber (29) of the precalcination stage (16) as solid sorbent may be combined with the off-gas (22) and/or with a partial gas discharge (38) of the rotary kiln off-gas in order to convert the sulfur oxides contained in those off-gases to calcium sulfate (34), which is subsequently separated from the system off-gas
Patent•
22 Feb 2001
TL;DR: In this paper, the authors propose to use a rotary tubular kiln with two firings to create a high-grade calcinated raw meal and an exhaust gas with very low NOx emissions.
Abstract: In order to create, for cement clinker production lines, a calcinator that is connected upstream from the rotary tubular kiln and is equipped with two firings, which enables on the one hand a high-grade calcinated raw meal and on the other hand an exhaust gas with very low NOx emissions, as well as a burning that is as complete as possible of remaining CO-containing NOx reduction zones, it is provided that a combustion point with sub-stoichiometric fuel combustion be arranged both in the rotary kiln exhaust gas ascending line and also in the cooler outgoing air line which form a first and section portion, respectively, of the calcinator and that downstream in a flow direction of the suspension, additional combustion air discharges into the calcinator which combustion air is branched off from the tertiary air line coming from the clinker cooler via at least one branch line.
TL;DR: In this article, the effects of temperature oscillations on the thermomechanical stresses in the refractory lining of a rotary kiln are considered and the authors consider the effect of the temperature oscillation on the rotary linings of the kiln.
Abstract: Effects of temperature oscillations on the thermomechanical stresses in the refractory lining of a rotary kiln are considered.
TL;DR: In this paper, the rotary kiln for the incineration of chemical waste is a poorly defined reactor in this network, and should ideally be controlled in a feedforward manner rather than in a feedback manner as is in the practice.
Patent•
30 Jul 2001
TL;DR: In this paper, a rotary kiln was used for reducing nitrogen oxide generation and removing sulfur from materials to create an oxygen deficient atmosphere. But the rotary Kiln was operated in a substoichiometric mode, and the combustion air (40C) completely combusts the combustible fuel (38) introduced by the burner.
Abstract: A calcining system (10) is operated in a substoichiometric mode for reducing nitrogen oxide generation and removing sulfur from materials (26) to be processed by creating an oxygen deficient atmosphere. The calcining system (10) includes a rotary kiln (14) rotating on a slightly inclined horizontal axis. The rotary kiln (14) has a feed end (22) introducing material (26) to be processed and a discharge end (24). A preheating/precalcining device (12) is positioned adjacent the feed end (22) such that the material (26) passes through the device (12) prior to entering the rotary kiln (14). A stationary hood (16) surrounds the discharge end (24). A burner (18) is supported by the stationary hood (16). The burner (18) introduces combustible fuel (38) and combustion air (40) into the rotary kiln (14) through the discharge end (24) and operates in a substoichiometric mode. At least on air nozzle (44) is located along the length of the rotary kiln (14). The air nozzle (44) injects combustion air (40) into the rotary kiln (14). The combustion air (40C) introduced by the air nozzle (44) completely combusts the combustible fuel (38) introduced by the burner (18) before the combustible fuel (38) exits the feed end (24).
Patent•
28 Sep 2001
TL;DR: In this paper, a method for treating polluted soil containing volatile organic compounds (VOC) and a method and an apparatus for producing a cement, whereby the way by which facilities such as cement kilns, provided in a cement production plant can be effectively used to treat VOC can be developed, the heating of polluted soil and the combustion of VOCs can be performed at a low cost, and a large amount of the treated detoxified soil can be efficiently utilized.
Abstract: PROBLEM TO BE SOLVED: To provide a method for treating polluted soil containing volatile organic compounds (VOC) and a method and an apparatus for producing a cement, whereby the way by which facilities, such as cement kilns, provided in a cement production plant can be effectively used to treat VOC can be developed, the heating of polluted soil and the combustion of VOC can be performed at a low cost, and a large amount of the treated detoxified soil can be effectively utilized. SOLUTION: The method for treating polluted soil comprises thermally desorbing volatile organic compounds (VOC) from polluted soil in a heating treatment apparatus, desirably, a rotary kiln or a rotary drier and burning and decomposing the separated VOC in a cement firing kiln 102.
Patent•
22 May 2001
TL;DR: In this article, a thermal decomposer capable of thermally decomposing a processed matter continuously to provide an excellent operating efficiency is presented, where a rotary kiln (3) is supported rotatably on a frame body (2) on both sides and driving devices (5a) are installed to rotate the rotary Kiln.
Abstract: A thermal decomposer capable of thermally decomposing a processed matter continuously to provide an excellent operating efficiency, wherein a rotary kiln (3)is supported rotatably on a frame body (2) on both sides and driving devices (5a) are installed to rotate the rotary kiln (3), a tubular crucible (17) is installed axially at the center of the rotary kiln (3), a spiral groove (17d) is provided axially in the inner wall of the crucible (17), a heating device (19) for heating the inside of the crucible (17) is installed in the rotary kiln (3), both open end parts of the crucible (17) are allowed to communicate with an inlet box (6) and an outlet box (7) supported on the frame body (2), a cut-off device for interrupting the communication between the outside and the inside of the crucible (17) is installed in the inlet box (6) and the outlet box (7), and the outlet box (7) is connected to a suction device (32) vacuating the inside of the crucible (17) and inducing the gas, produced when the processed matter is decomposed, from the crucible (17), whereby the processed matter charged in the crucible (17) can be thermally decomposed by vacuating the inside of the crucible (17) and then heating the crucible
Patent•
[...]
19 Jan 2001
TL;DR: In this article, a rotary kiln-based direct coal fired burner system for conveying coal is described, where the shape of the emerging flame is controlled by a first annulus of swirling tertiary air adjacent to the primary airstream and by a second annulus defining an outer envelope for the flame.
Abstract: A direct coal fired burner system (22) for a rotary kiln (20) in which the burner (36) has a multi-barrel construction through which primary air for conveying coal is heated with tertiary air sourced from the rotary kiln (20), and the shape of the emerging flame is controlled by a first annulus of swirling tertiary air adjacent the primary airstream and by a second annulus of laminar tertiary air defining an outer envelope for the flame The volume and relative velocities of air in the tertiary air supplies are all controllable through the use of respective dampers provided in tertiary air supply conduits
Patent•
18 Jun 2001
TL;DR: In this paper, a pivoting throttle valve (33) is positioned in the precalcination stage to control the quantity of rotary kiln off-gas and thus the O 2 content in the kiln OFF gas.
Abstract: Cement clinker production apparatus having a precalcination stage connected upstream of a rotary kiln, in which precalcination stage a CO-containing reduction zone in the rotary kiln off-gas duct is employed for the purpose of reducing the pollutant NO x . In order to make certain that the quantitative ratio of O 2 in the rotary kiln off-gas to fuel admitted by a deNO x burner, and thus control the effectiveness of NO x reduction, a pivoting throttle valve ( 33 ) is positioned in the precalcination stage to control the quantity of rotary kiln off-gas and thus the O 2 content in the kiln off-gas. The throttle valve ( 33 ) is positioned in the rotary kiln off-gas duct ( 15 ) above the deNO x burner ( 19 ), above the raw meal inlet ( 13 ), and before the confluence of the tertiary air substream with the rotary kiln off gas. The throttle valve ( 33 ) is pivotable about an articulation ( 34 ) at the bottom side of the valve so that the flow of the rotary kiln offgas remains laminar, thus enhancing the reaction length of the CO-containing reduction zone ( 23 ).
TL;DR: The main accent in the study of cement clinker-based refractory materials was placed on an optimum choice of the clinkerto-cement proportion, on a rational chemical, mineral, and granulometric composition of clinker, on the development of techniques for laying and fixing the lining, on optimal choice of water tocement ratio, and the use of various additions for increasing the heat resistance of the concrete as discussed by the authors.
Abstract: The main accent in the study of cement clinker-based refractory materials was placed on an optimum choice of the clinker-to-cement proportion, on a rational chemical, mineral, and granulometric composition of the clinker, on the development of techniques for laying and fixing the lining, on an optimum choice of water-to-cement ratio, on the use of various additions for increasing the heat resistance of the concrete, etc.
Patent•
28 Mar 2001
TL;DR: In this paper, a carbide containing hard incombustibles and obtained from a rotary kiln was charged into a cage mill having no cutting blade. And the carbide, which is brittle, was selectively cracked into fine particles, and the particles are separated from the incombusibles which are hard and are not cracked.
Abstract: PROBLEM TO BE SOLVED: To surely separate and remove hard incombustibles contained in a carbide without using a grinder or crusher having a cutting blade to thereby efficiently recover a high-purity carbide. SOLUTION: A carbide containing incombustibles and obtained from a rotary kiln 2 is charged into a cage mill 3 having no cutting blade. The carbide, which is brittle, is selectively cracked into fine particles, and the particles are separated from the incombustibles which are hard and are not cracked. Thus, a high- purity carbide can be efficiently recovered. COPYRIGHT: (C)2002,JPO
Patent•
04 Jun 2001
TL;DR: A rotary kiln as mentioned in this paper includes a novel air conveying system for delivering a supply of port air beneath the material bed of feed stock passing through the interior of the kiln, which includes an air inlet port (50) disposed in the shell of a kiln.
Abstract: A rotary kiln (18) includes a novel air conveying system for delivering a supply of port air beneath the material bed of feed stock passing through the interior of the kiln. The air conveying system includes an air inlet port (50) disposed in the shell of the kiln, a main air conveying channel (85) which communicates with the air inlet port, and a plurality of air vent channels (75) communicating with the main air conveying channel and the interior chamber of the kiln. The main air conveying channel (85) is formed integrally in the refractory bricks which line the inner surface of the kiln shell and extends longitudinally and parallel to the rotary axis of the kiln. The air vent channels (75) extend through the refractory bricks substantially radially with respect to the rotary axis of the kiln.
01 Jan 2001
TL;DR: Norcem's experience with combustion of solid alternative fuels in Kiln #6 at the Dalen cement plant in Brevik, Norway is described in this article, where coal and petcoke are most frequently used, but oil and natural gas are also burnt in some plants.
Abstract: Today virtually all cement clinker burning processes take place in rotary kilns. A mixture of calcareous and argilaceous materials is heated to a temperature of about 1450 °C. In this process decarbonation followed by partial fusion occurs, and nodules of so-called clinker are formed. The cooled clinker is mixed with a few percent of gypsum, and ground into a fine meal – cement. The most modern cement kilns are equipped with a precalciner, in which most of the calcium carbonate decomposes into calcium oxide and carbon dioxide, before the precalcined meal enters the rotary kiln, where the rest of the burning takes place. The endothermic cement burning process requires large amounts of thermal energy, which is supplied by fuel combustion in the rotary kiln and in the precalciner. Coal and petcoke are most frequently used, but oil and natural gas, are also burnt in some plants. However, due the negative impact of the fossil fuels on the environment, alternative fuels are utilized to an ever increasing extent. Norcem, Norway's sole cement manufacturer, has experience with alternative fuel combustion since 1987, when combustion of liquid hazardous waste (LHW) was started. Since then, different types of solid alternative fuels, such as solid hazardous waste (SHW) and refuse derived fuel (RDF), has come into regular use. This paper presents Norcem's experience with combustion of solid alternative fuels in Kiln #6 at the Dalen cement plant in Brevik, Norway.
Patent•
20 Feb 2001
TL;DR: In this paper, a rotary kiln is used to provide a smelting reduction method for iron oxide using a carbonaceous material for reducing the iron oxide and slag-making agent for preventing the formation of a ring onto the furnace wall.
Abstract: PROBLEM TO BE SOLVED: To provide a smelting reduction method for iron oxide using a rotary kiln with which service life of a refractory is extended longer than that in the conventional method, and the formation of a ring onto the furnace wall in the rotary kiln can be prevented by setting the operational temperature of the rotary kiln to a lower temperature than the conventional smelting reduc tion temperature. SOLUTION: In the smelting reduction method for iron oxide using the rotary kiln 11 which obtains molten iron 25 by heating and reducing the iron oxide in the furnace 28 of the rotary kiln 11, mixed raw material is manufactured constituting essentially of the iron oxide, a carbonaceous material for reducing the iron oxide and slag-making agent for preventing the formation of the ring onto the furnace wall 29 in the rotary kiln 11 when the molten iron is produced, and this mixed raw material is charged in the furnace 28 of the rotary kiln 11 having an atmospheric temperature of ≥1200°C in the furnace, and the iron oxide is reduced with the carbonaceous material to obtain the molten iron 25. COPYRIGHT: (C)2002,JPO
Patent•
09 Mar 2001
TL;DR: In this paper, a method of increasing the clinker output of an existing cement plant and of producing steam, a raw meal is preheated in a preheater (50), then burned in a rotary kiln (16) to form clinker, and clinker is cooled in a clinker cooler (20).
Abstract: In a method of increasing the clinker output of an existing cement plant and of producing steam, a raw meal is preheated in a preheater (50), then burned in a rotary kiln (16) to form clinker, and the clinker is cooled in a clinker cooler (20). Calcined raw meal, consisting essentially of lime and combustion residues like ash, carbon and desulfurization residues is fed to the preheater (50). Process air from the clinker cooler (20) is directed to the preheater (50) in countercurrent flow to the direction of flow of the calcined raw meal. The calcined preheated raw meal is directed to the rotary kiln (16). The kiln exhaust gases are 100 % bypassed and used for steam production in a boiler (60). The kiln exhaust gases are quenched to a temperature of about 800-900 °C prior to their heat exchange in the water/steam cycle.