EP0437407B1 - Méthode de frittage de minerais de fer fin, utilisant deux systèmes d'allumage - Google Patents

Méthode de frittage de minerais de fer fin, utilisant deux systèmes d'allumage Download PDF

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Publication number
EP0437407B1
EP0437407B1 EP19910400055 EP91400055A EP0437407B1 EP 0437407 B1 EP0437407 B1 EP 0437407B1 EP 19910400055 EP19910400055 EP 19910400055 EP 91400055 A EP91400055 A EP 91400055A EP 0437407 B1 EP0437407 B1 EP 0437407B1
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EP
European Patent Office
Prior art keywords
sintering
charge
layer
lower layer
exhaust gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19910400055
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German (de)
English (en)
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EP0437407A1 (fr
Inventor
Takazo Kawaguchi
Masaru Matsumura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
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Sumitomo Metal Industries Ltd
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Filing date
Publication date
Priority claimed from JP404990A external-priority patent/JPH03211239A/ja
Priority claimed from JP27098390A external-priority patent/JPH0791594B2/ja
Application filed by Sumitomo Metal Industries Ltd filed Critical Sumitomo Metal Industries Ltd
Publication of EP0437407A1 publication Critical patent/EP0437407A1/fr
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Publication of EP0437407B1 publication Critical patent/EP0437407B1/fr
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/16—Sintering; Agglomerating
    • C22B1/20—Sintering; Agglomerating in sintering machines with movable grates
    • C22B1/205—Sintering; Agglomerating in sintering machines with movable grates regulation of the sintering process
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/16—Sintering; Agglomerating
    • C22B1/20—Sintering; Agglomerating in sintering machines with movable grates

Definitions

  • the present invention relates to a method for sintering fine iron ore using a dual layer system, i. e., a dual ignition system.
  • Fine iron ore is sintered into the form of lumps prior to being charged into a blast furnace for producing pig iron.
  • charge or "sintering charge”
  • DL Light-Lloyd
  • Figure 1 schematically shows a DL sintering apparatus, in which a train of pallets are provided around a sintering strand and bed ore and a charge for sintering are successively supplied onto the pallets through hoppers 3 and 4, respectively.
  • a train of pallets are provided around a sintering strand and bed ore and a charge for sintering are successively supplied onto the pallets through hoppers 3 and 4, respectively.
  • the charge on the pallets passes through an ignition furnace 5
  • the charge is set fire on its surface. Since air is drawn downwardly via a wind box 6 with a blower 7, sintering is performed through the charge from the top to the bottom of the layer while the pallet moves toward an outlet end of the sintering apparatus.
  • FIG. 2 The progress of sintering is illustrated in Figure 2, in which a layer of charge, i.e., a sintering charge zone 8 is placed on the pallet.
  • the hatched zone indicates a sintering reaction zone 9 where a charge is being progressively sintered.
  • a zone placed on the sintering reaction zone 9 is a sintering-finished zone 10 in which the sintering process has been finished.
  • a charge for sintering which contains fine coke as a solid fuel is set fire with an ignition furnace 5. While it travels along the sintering strand, air containing about 21 vol% of oxygen is blown through the layer to carry out combustion of the fine coke. The heat generated by the combustion of coke partly melts and sinters fine iron ore. Usually it takes about 30 minutes for the sintering front to reach the bottom of the layer after ignition.
  • a combustion gas is removed through a wind box 6 and the oxygen content thereof is about 11 vol% at a temperature of about 100 °C. Combustion gas having an oxygen content of this level has the ability to combust coke. So, recycling of such a combustion gas is desirable.
  • Document FR-A-2 468 653 discloses a method for sintering fine iron ore using a dual layer system, in which two layers of sintering charge are placed on a train of pallets and each of the layers is set on fire at given intervals of time to perform sintering of the charge.
  • anthracite is used as a fuel in the two layers.
  • the double layer system is superior to the single layer system in respect to productivity, the strength of the resultant product is small.
  • An object of the present invention is to provide a method for sintering fine iron ore using a dual layer system, in which problems regarding a lack of oxygen in the lower layer and a decrease in the strength of sintered lumps can be eliminated.
  • Another object of the present invention is to provide a method for sintering fine iron ore using a dual layer system, in which the use of fine coke and anthracite as solid fuel can be avoided and instead cheap coal can be used without causing problems due to the evolution of volatile matters.
  • the present invention resides in a method for sintering fine iron ore using a dual layer system, in which two layers of sintering charge are placed on a train of pallets and each of the layers is set on fire at given intervals of time to perform sintering of the charge, and wherein the lower layer of the charge contains as a solid fuel coal containing the volatile matter in an amount of 10 wt% or lower, characterized in that at least part of solid fuel which is contained in the charge of the upper layer is coal containing at least 10 wt% of volatile matter.
  • the lower layer of the charge is set on fire to start sintering
  • the upper layer of the charge is set on fire to start sintering of the upper layer when the front flame point (FFP) reaches the grates of the pallet and the sintered lumps of the charge of the lower layer start being cooled while the charge of the upper layer is sintered.
  • FFP front flame point
  • the volatile matter can be analyzed by conventional analyzing methods such as those specified in JIS (Japanese Industrial Standards).
  • Figure 4 schematically illustrates the progress of sintering together with the composition and temperature of exhaust gas, which vary in the travelling direction of the pallets.
  • the temperature of exhaust gas is kept at about 65°C for a while after ignition, then it starts increasing to reach a peak of around 500°C, and gradually decreases.
  • the oxygen content of the exhaust gas decreases and the content of CO and CO2 increases while the temperature of the exhaust gas is kept around 65°C.
  • the content of CO and CO2 decreases to the same level as that found just after ignition.
  • a change in the composition of the exhaust gas depends on the progress of sintering reactions within the layer.
  • exhaust gas is cooled in this zone 8 so that the temperature of the exhaust gas is kept at the dew point of the exhaust gas , i.e., about 65°C.
  • the hatched area in Figure 4 is a sintering reaction zone 9 where a sintering reaction occurs.
  • FFP front flame point
  • the coke contained in the charge combusts with oxygen, and the oxygen content of the exhaust gas decreases to as low as about 10 vol% and the content of CO and CO2 increases.
  • the temperature of the exhaust gas rapidly increases to a peak temperature and the coke contained therein is completely combusted, resulting in an increase in the oxygen content and a decrease in the content of CO and CO2.
  • the upper layer is set on fire and coke contained therein combusts while the combustion of coke takes place in the lower layer before the FFP reaches the bottom of the layer.
  • a shortage of oxygen in the lower layer is unavoidable.
  • the upper layer preferably is set on fire when the FFP of the first layer, i.e., the lower layer reaches the bottom of the first layer. Namely, after confirming the completion of sintering in the first layer, the ignition of the upper layer is carried out in order to ensure the presence of a sufficient amount of oxygen in air to be blown through the lower layer.
  • the cooling state is different for each of the layers, but the sintering is completed for both layers. Therefore, the upper and lower layers can be simultaneously discharged and crushed and the crushed products can be efficiently cooled with a conventional cooler.
  • both layers can be cooled to substantially the same temperature level at the discharge end of the sintering strand.
  • the discharge point for each of the layers i. e., the timing for discharging can be delayed for the lower layer, and the difference in the temperature of the layers can also be minimized.
  • Figure 5 illustrates the arrangement of the sintering apparatus for carrying out the present invention.
  • the same reference numerals indicate the same members as in Figure 2.
  • flooring ore and a sintering charge are continuously supplied through hoppers 3 and 4 onto the pallets to form an ore bed and a lower layer of the sintering charge, respectively.
  • the top surface of the lower layer is set on fire when it travels under the ignition furnace 5. Air passes from the top to the bottom of the lower layer since air suction is carried out by means of a blower 7 through a series of wind boxes 6 which are provided under the travelling pallets.
  • Another set of a hopper 11 and an ignition furnace 12 is provided above a central area of the strand in the travelling direction.
  • An additional charge is supplied through the hopper 11 onto the surface of the lower layer of the charge so as to form an additional layer of the charge.
  • the lower layer has been sintered, i.e., the FFP has reached the bottom of the lower layer.
  • This additional layer is also set on fire when it travels under the ignition furnace 12. Since suction of air through a series of wind boxes 6 is continued, air passes from the top of this additional layer to the bottom of the lower layer, the sintering of which has been finished.
  • sintered lumps of fine iron ore are discharged from the sintering machine at the outlet end of the sintering strand and then crushed and mixed with each other in a crusher 13.
  • the crushed lumps are supplied to an air-blowing cooler 15 provided with a blower 14 and are cooled within this cooler.
  • an exhaust gas boiler 19 and a blower 20 are provided in order to recover heat from the exhaust gas from the last half of the sintering strand.
  • a temperature sensor 16 and/or a gas sampler 17 are provided in each of the boxes 6 to determine the FFP by measuring the starting point of an increase in temperature, or an increase in the oxygen content, or a decrease in the CO and CO2 content of the exhaust gas.
  • the travelling rate of the pallets is controlled so that the temperature sensor 18 provided in the cooler 15 indicates a given temperature.
  • sensor 16 provided in the boxes 6 may be used.
  • the travelling rate of the pallets must be decreased.
  • the travelling rate can be increased.
  • the ratio of the depth of the lower layer to that of the upper layer is adjusted so that the FFP is located on the sintering strand at a point just below or a little upstream of the ignition furnace 12. If the depth of the upper layer is increased, the FFP moves toward the ignition furnace 5. When the depth of the lower layer is increased, the FFP shifts toward the discharge end of the sintering strand.
  • coal having a high content of volatile matter is used as at least part of the solid fuel in an upper layer. Therefore, before it is heated to the point of catching fire, i.e., around 500°C, the volatile matter in the coal is vaporized. Vaporized volatile matter is entrained in combustion gas drawn downwardly through a sintering charge zone 8 in the upper layer and then goes into a lower layer. When the volatile matter reaches a sintering finishing zone 10 and a sintering reaction zone 9 in the lower layer, it combusts.
  • the volatile matter evaporated in the upper layer is combusted in a high temperature zone of the lower layer and is never released from the layer.
  • a solid fuel which can be combined in the lower layer comprises a coke substantially free of volatile matter or anthracite with a small content of volatile matter.
  • a solid fuel which can be combined in the lower layer comprises a coke substantially free of volatile matter or anthracite with a small content of volatile matter.
  • the amount of tar which is carried in an exhaust gas is very small. Therefore, as long as the coal contains 10 wt% or less of volatile matter, steam coal may be used as a solid fuel even in the lower layer.
  • the content of volatile matter of coal which is combined in the upper layer is restricted to not lower than 10 wt%, because coal having volatile matter in an amount of smaller than 10 wt% may be used in a single layer system, so there is no need to employ the dual layer system.
  • the volatile matter evaporated from the coal is carried in an exhaust gas and deposit as tar pitch on the inner wall within the exhaust gas piping.
  • Such coal cannot be used in a single layer system.
  • such coal having a high content of volatile matter can be used in the upper layer. This is advantageous from a practical viewpoint.
  • a DL-sintering apparatus of the strand cooling type, as illustrated in Figure 5, was used to carry out sintering of fine iron ore in accordance with the double layer system.
  • the length of a sintering strand was 100 meters.
  • Table 1 shows the composition of the charge employed in this example.
  • Table 2 shows the operating conditions.
  • Comparative Example 1 employed the double layer system, and the arrangement of the hopper 11 and the ignition furnace 12 was that shown in Figure 1. The hopper 11 and the ignition furnace 12 were placed at a position rather close to the ignition furnace 5 for the lower layer.
  • Comparative Examples 2 and 3 employed a single layer system.
  • the FFP was positioned 54 meters away from the ignition point, i.e., near the central area of the strand in the travelling direction of the pallets.
  • the FFP was positioned 74 meters away from the ignition point, i.e., about midway between the central area and the discharge end of the strand.
  • the charge used was the same as in the working examples of the present invention.
  • Test results are shown in Figure 6 and Table 3.
  • the abscissa of Figure 6 indicates the distance (meters) from the ignition furnace 5 for the lower layer.
  • a distance of 100 meters represents the discharge end of the strand, i.e., the outlet end of the sintering strand.
  • the temperature of the combustion gas started increasing at a point 43 meters away from the ignition furnace 5. This point corresponds to the FFP.
  • the oxygen content which once decreased to around 10 vol% due to the ignition of the lower layer again increased after passing the FFP.
  • the content of CO and CO2 decreased after passing the FFP.
  • the ignition of the upper layer was carried out at a distance of 47 m away on the sintering strand. After this point, there was no difference in the temperature of the exhaust gas for a single layer system such as shown in Figure 4, but the oxygen content decreased and the content of CO and CO2 increased after the ignition of the upper layer.
  • the upper layer was set on fire at a point 8 m away from the ignition point for the lower layer, and after ignition the O2 content of the exhaust gas decreased from 10 vol% to nearly 0 vol%, but the content of CO and CO2 increased to 5 vol% and 25 vol%, respectively.
  • the starting point of an increase in temperature of the exhaust gas was the FFP, i.e., 68 m away from the ignition point for the lower layer.
  • Comparative Examples 2 and 3 employed a single sintering layer system, in which the temperature increased, the content of O2 decreased, and the content of CO and CO2 increased for the exhaust gas after the point corresponding to the FFP.
  • Example 1 was repeated using the sintering apparatus of the DL type to sinter fine iron ore, but various solid fuels were employed and the content of tar contained in an exhaust gas was determined.
  • the sintering charge used was the same as in Example 1.
  • Case-1 shows the case of the single ignition system
  • Cases-3 and -4 are the case of a dual ignition system.
  • Test results are shown in Table 5 for Case-1, Table 6 for Case-2, and Table 7 for Case-3.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Claims (4)

  1. Procédé de frittage d'un minerai de fer fin en employant un système à double couche, selon lequel on dispose deux couches de charge à fritter sur un train de palettes, chacune des couches étant enflammée selon des intervalles de temps donnés, afin d'effectuer le frittage de la charge, la couche inférieure de la charge, contenant, comme combustible solide, du charbon ayant une teneur en matières volatiles de 10 % en poids ou moins, caractérisé en ce qu'au moins une partie du combustible solide contenu dans la charge de la couche supérieure est du charbon ayant une teneur en matières volatiles de 10 % en poids ou plus.
  2. Procédé selon la revendication 1, dans lequel la couche inférieure de la charge est enflammée pour commencer le frittage, et la couche supérieure de la charge est enflammée pour commencer le frittage de la couche supérieure lorsque le point d'inflammation frontal atteint les grilles de la palette, et les blocs frittés de la couche inférieure commencent à être refroidis tandis que la charge de la couche supérieure est frittée.
  3. Procédé selon la revendication 2, dans lequel le temps pour que le point d'inflammation frontal ait atteint les grilles est déterminé en mesurant la température du gaz évacué du fond des palettes, par analyse de la composition chimique du gaz évacué ou en effectuant les deux.
  4. Procédé selon la revendication 2 ou 3, dans lequel le temps pour que le point d'inflammation frontal atteigne les grilles est ajusté en faisant varier la vitesse de déplacement des palettes et la profondeur de la couche inférieure.
EP19910400055 1990-01-11 1991-01-11 Méthode de frittage de minerais de fer fin, utilisant deux systèmes d'allumage Expired - Lifetime EP0437407B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP4049/90 1990-01-11
JP404990A JPH03211239A (ja) 1990-01-11 1990-01-11 ２段点火式焼結方法
JP27098390A JPH0791594B2 (ja) 1990-10-09 1990-10-09 ２段点火焼結法
JP270983/90 1990-10-09

Publications (2)

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EP0437407A1 EP0437407A1 (fr) 1991-07-17
EP0437407B1 true EP0437407B1 (fr) 1995-03-29

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EP (1) EP0437407B1 (fr)
DE (1) DE69108414T2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100465564C (zh) * 2007-06-08 2009-03-04 王梓骥 烧结料床实行一次给料、两侧铺料、两处点火烧结工艺
CN105543471A (zh) * 2016-02-01 2016-05-04 中南大学 一种基于抑制铁矿烧结过程燃料氮转化的NOx控制方法

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4411505C1 (de) * 1994-03-31 1995-08-24 Steag Ag Verfahren und Anordnung zum Sintern metalloxidhaltiger Werkstoffe
WO1995027802A1 (fr) * 1994-04-06 1995-10-19 Steag Aktiengesellschaft Procede et systeme de traitement thermique de materiaux
BR9501161A (pt) * 1995-03-22 1997-05-27 Siderurgica Nacional Sa Processo de sinterizaçao de minério com múltiplas frentes de queima na camada de mistura a sinterizar
DE19513550B4 (de) * 1995-04-10 2005-03-03 Siemens Ag Pelletieranlage
AT405530B (de) 1996-07-11 1999-09-27 Voest Alpine Ind Anlagen Verfahren zur thermischen behandlung von organisch belasteten materialien
DE202008005553U1 (de) 2008-04-22 2008-08-14 Evonik Degussa Gmbh Hochleitfähige, transparente Metalloxid-Schichten durch Plasmaimmersion
CN106337113B (zh) * 2016-03-15 2018-08-03 鞍钢股份有限公司 一种采用预烧结的超厚料层烧结方法
CN106350664A (zh) * 2016-09-12 2017-01-25 鞍钢股份有限公司 一种采用预烧结的超厚料层上层烧结终点的判断方法
CN106337115B (zh) * 2016-09-12 2018-08-03 鞍钢股份有限公司 一种抽风和鼓风相结合的超厚料层烧结方法及烧结机

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE759456A (fr) * 1969-11-27 1971-04-30 Arbed
BE769840A (fr) * 1971-07-09 1972-01-10 Centre Rech Metallurgique Procede d'agglomeration de minerais de fer.
US3949974A (en) * 1972-11-08 1976-04-13 Kawasaki Steel Corporation Apparatus for preventing raw mix from being unevenly sintered by a sintering machine
FR2468653A1 (fr) * 1979-10-26 1981-05-08 Creusot Loire Procede perfectionne et installation d'agglomeration de melanges mineraux

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100465564C (zh) * 2007-06-08 2009-03-04 王梓骥 烧结料床实行一次给料、两侧铺料、两处点火烧结工艺
CN105543471A (zh) * 2016-02-01 2016-05-04 中南大学 一种基于抑制铁矿烧结过程燃料氮转化的NOx控制方法
CN105543471B (zh) * 2016-02-01 2017-11-21 中南大学 一种基于抑制铁矿烧结过程燃料氮转化的NOx控制方法

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DE69108414D1 (de) 1995-05-04
DE69108414T2 (de) 1995-11-09
EP0437407A1 (fr) 1991-07-17

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