JPH04165025A - Manufacture of reduced pellet - Google Patents
Manufacture of reduced pelletInfo
- Publication number
- JPH04165025A JPH04165025A JP29151990A JP29151990A JPH04165025A JP H04165025 A JPH04165025 A JP H04165025A JP 29151990 A JP29151990 A JP 29151990A JP 29151990 A JP29151990 A JP 29151990A JP H04165025 A JPH04165025 A JP H04165025A
- Authority
- JP
- Japan
- Prior art keywords
- pellet
- pellets
- binder
- coke
- coating material
- 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.)
- Pending
Links
- 239000008188 pellet Substances 0.000 title claims abstract description 92
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 22
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000011248 coating agent Substances 0.000 claims abstract description 21
- 238000000576 coating method Methods 0.000 claims abstract description 21
- 239000011230 binding agent Substances 0.000 claims abstract description 19
- 239000000440 bentonite Substances 0.000 claims abstract description 18
- 229910000278 bentonite Inorganic materials 0.000 claims abstract description 18
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000002994 raw material Substances 0.000 claims abstract description 18
- 239000000463 material Substances 0.000 claims abstract description 17
- 239000000843 powder Substances 0.000 claims abstract description 9
- 239000000428 dust Substances 0.000 claims abstract description 5
- 238000004898 kneading Methods 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 17
- 238000002156 mixing Methods 0.000 claims description 9
- 238000010304 firing Methods 0.000 claims description 7
- 239000003575 carbonaceous material Substances 0.000 claims description 6
- 239000000571 coke Substances 0.000 abstract description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 13
- 238000011946 reduction process Methods 0.000 abstract description 9
- 238000005469 granulation Methods 0.000 abstract description 2
- 230000003179 granulation Effects 0.000 abstract description 2
- 230000003750 conditioning effect Effects 0.000 abstract 3
- 238000005507 spraying Methods 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 20
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 10
- 239000007789 gas Substances 0.000 description 9
- 239000003638 chemical reducing agent Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 8
- 238000007796 conventional method Methods 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000002344 surface layer Substances 0.000 description 5
- 239000011247 coating layer Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 229940095674 pellet product Drugs 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 239000000395 magnesium oxide Substances 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- YOBAEOGBNPPUQV-UHFFFAOYSA-N iron;trihydrate Chemical compound O.O.O.[Fe].[Fe] YOBAEOGBNPPUQV-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000011345 viscous material Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Landscapes
- Manufacture And Refinement Of Metals (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は還元ペレットの製造方法に係り、特に生ペレッ
トを２重構造とし、通常方法によって製造した内層生ペ
レツト上に還元剤と粘結剤のみより成る粉状被覆材を被
覆して外殻を形成し、次の還元工程において還元するこ
とにより全体の強度を維持しつつ還元率を向上させるこ
とができる還元ペレットの製造方法に関し、効率的な高
炉原料の製造分野において利用される。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing reduced pellets, and in particular, green pellets are made into a double structure, and a reducing agent and a binder are added to the inner layer of the green pellets produced by a conventional method. An efficient method for producing reduced pellets that can improve the reduction rate while maintaining the overall strength by coating the powdered coating material consisting of wood to form an outer shell and reducing it in the next reduction process. It is used in the field of producing blast furnace raw materials.
従来、還元ペレットはグレートキルン方式もしくはロー
タリーキルン方式によって製造されて来た。Conventionally, reduced pellets have been produced by a grate kiln method or a rotary kiln method.
例えばグレートキルン方式による場合は、通常微粉鉄鉱
石もしくは酸化鉄ダストの主原料にベントナイト等の粘
結剤とコークス粉等の如き炭素質物質を混合し、ディス
クペレタイザー等にて造粒して生ペレットを製造する。For example, when using the great kiln method, the main raw materials are usually fine iron ore or iron oxide dust, a binder such as bentonite, and a carbonaceous material such as coke powder are mixed, and the mixture is granulated using a disc pelletizer or the like to produce raw pellets. Manufacture.
この生ペレットをグレートキルンに装入し、通常２００
〜３００℃の温度で乾燥した後、使用鉱石中に結晶水を
有する場合には更に４００℃程度に加熱して結晶水を除
去し、次いで８００〜１０００℃の温度で予熱し硬化す
る。この予熱ペレットはグレ−トからキルンに移され、
同時に炭素質物質を外装添加して、ガスバーナー等にて
加熱すると共に空気を送給して還元ガスＣＯを燃焼させ
、
Ｆｅ２Ｏ３→Ｆｅ、Ｏ，−＋Ｆｅ０−＋Ｆｅ に還元
して還元ペレットを製造する方法をとっている。This raw pellet is charged into a grate kiln, and usually 200
After drying at a temperature of ~300°C, if the ore used contains water of crystallization, it is further heated to about 400°C to remove the water of crystallization, and then preheated at a temperature of 800 to 1000°C to harden. This preheated pellet is transferred from the grate to the kiln,
At the same time, a carbonaceous material is added to the exterior, heated with a gas burner, etc., and air is supplied to burn the reducing gas CO, reducing Fe2O3 → Fe, O, -+Fe0-+Fe to produce reduced pellets. method.
また、ロータリーキルン方式による方法は、生ペレット
を直接キルンに装入して還元するか、焼成したペレット
をキルンに装入還元するか、もしくはキルンの前にトラ
ベリンググレートを設置し、生ペレットを予熱硬化した
後キルンに装入して還元する等の方法があり、これらの
方法についても従来多くの研究が開示されている。これ
らの従来技術の概要について説明する。In addition, in the rotary kiln method, raw pellets are directly charged into the kiln for reduction, fired pellets are charged into the kiln and reduced, or a traveling grate is installed in front of the kiln and the raw pellets are preheated and hardened. There are methods such as charging it into a kiln and reducing it, and many studies have been disclosed regarding these methods. An overview of these conventional techniques will be explained.
特開昭５３−２１００５（特公昭５６−３６６９０）こ
の発明はグレートキルン方式による還元ペレットの製造
方法に関するものであって、その要旨とするところは次
の如くである。すなわち、「炭素質材料を５〜２０％含
有する生ペレットをグレートキルンに装入し、予熱、焼
成して還元ペレットを製造する方法において、グレート
に供給される予熱ガスの温度Ｔ’Ｃを９００〜１１９０
℃に保つと共に、予熱ガス中の酸素濃度〔○〕（％）と
予熱ガス温度との関係が、
２．４Ｘ１０ （Ｔ−１２６０）−０，１２≧〔○〕
≧２．４Ｘ１０ （Ｔ−１２６０）−２，６２となる
ように、予熱ガス温度と予熱ガス中の酸素濃度とを調整
し、グレートにおける生ペレットの予熱温度を１０５０
〜１１５０℃に保持するほか、生ペレット層の下に粒状
の炭素物質を床敷して操業を行うことを特徴とするグレ
ートキルン方式による還元ペレットの製造方法。」であ
る。JP-A-53-21005 (Japanese Patent Publication No. 56-36690) This invention relates to a method for producing reduced pellets using a great kiln system, and its gist is as follows. That is, "in a method of producing reduced pellets by charging raw pellets containing 5 to 20% of carbonaceous material into a grate kiln, preheating and firing, the temperature T'C of the preheated gas supplied to the grate is set to 900 ~1190
℃, and the relationship between the oxygen concentration in the preheated gas [○] (%) and the preheated gas temperature is 2.4X10 (T-1260) - 0,12 ≧ [○]
Adjust the preheating gas temperature and the oxygen concentration in the preheating gas so that ≧2.4
A method for producing reduced pellets using a great kiln method, which is characterized in that the temperature is maintained at ~1150°C and that granular carbon material is spread under a layer of raw pellets. ”.
しかし、この方法は上記の如く予熱温度を１０５０〜１
１５０℃の如く高温に保持する結果熱交換後の排ガス温
度が高くなるため、省エネルギーに反する方法と言わざ
るを得す、更に予熱温度が高いことによる予熱機内のグ
レートなどの機械部品の損傷を早める欠点がある。However, this method requires a preheating temperature of 1050 to 1
As a result of maintaining the temperature at a high temperature such as 150°C, the temperature of the exhaust gas after heat exchange increases, so it must be said that this method is contrary to energy conservation.Furthermore, the high preheating temperature accelerates damage to mechanical parts such as the grate inside the preheater. There are drawbacks.
この発明の要旨とするところは次の如くである。The gist of this invention is as follows.
すなわち、「主原料である微粉鉄鉱石、含鉄ダスト等を
造粒して得られた生ペレットをトラベリンググレート上
で順次乾燥、予熱および焼成を行い硬化ペレットとなし
た後、前記硬化ペレットをロータリーキルンによりガス
あるいは固体還元材で還元を行なうグレートキルン方式
による還元ペレットの製造方法において、前記主原料に
、マグネシウム酸化物を１重量％以上、５重量％以下添
加することを特徴とする還元ペレットの製造方法。」で
ある。That is, "raw pellets obtained by granulating the main raw materials, such as fine iron ore and iron-containing dust, are sequentially dried, preheated, and fired on a traveling grate to form hardened pellets, and then the hardened pellets are heated in a rotary kiln. A method for producing reduced pellets by a great kiln method in which reduction is carried out with a gas or solid reducing agent, characterized in that 1% by weight or more and 5% by weight or less of magnesium oxide is added to the main raw material. .”
しかし、この方法は高価なＭｇＯを配合することにより
製造原価の高騰を来すという欠点がある。However, this method has the disadvantage that the production cost increases due to the inclusion of expensive MgO.
本発明の目的は、還元ペレット製造における上記従来技
術の欠点を解決し、簡単な方法で原価の上昇を来すこと
なく、強度の大なる還元ペレットをすぐれた還元率で製
造することのできる効果的な製造方法を提供するにある
。The purpose of the present invention is to solve the drawbacks of the above-mentioned conventional techniques in producing reduced pellets, and to produce strong reduced pellets with an excellent reduction rate using a simple method without increasing the cost. The aim is to provide a manufacturing method that is
本発明の要旨とするところは次の如くでる。 The gist of the present invention is as follows.
すなわち、主原料である微粉鉱石もしくは酸化物ダスト
に粘結剤および炭素質材料を混合した後逸粒して生ペレ
ットを製造する工程と、前記生ペレットを還元炉に装入
して予熱、焼成後還元雰囲気で還元する工程と、を有し
て成る還元ペレットの製造方法において、前記主原料に
重量比にて１．６〜２．４％のベントナイトと１６％以
上のコークス粉を調質混練した後造粒して内層生ペレッ
トを形成する段階と、前記内層生ペレットの外側に重量
比にてコークス粉８７〜９５％、粘結剤１３〜５％より
成る粉状被覆材を前記内層生ペレットに対し重量比にて
３〜１０％被覆して外層を形成する段階と、より成る前
記生ペレットの製造工程を有することを特徴とする還元
ペレットの製造方法である。Specifically, there is a step of mixing a binder and a carbonaceous material with fine ore or oxide dust, which is the main raw material, and then crushing it to produce green pellets, and a step of charging the green pellets into a reduction furnace, preheating, and firing them. A method for producing reduced pellets comprising the step of reducing in a reducing atmosphere, wherein the main raw material is tempered and kneaded with 1.6 to 2.4% of bentonite and 16% or more of coke powder by weight. A step of post-granulating to form inner raw pellets, and applying a powder coating material consisting of 87 to 95% coke powder and 13 to 5% binder by weight on the outside of the inner raw pellets. This method of producing reduced pellets is characterized by comprising a step of forming an outer layer by coating the raw pellets with a weight ratio of 3 to 10%, and a step of producing the green pellets.
本発明者らは還元ペレットの強度と還元率の向上につい
て研究中のところ、還元率を上げるためには内装する還
元剤のコークス粉の配合率を増加すればよいが、ある限
度以上に増加すると還元ペレットの強度が低下して粉化
するので、表面層のみ還元剤を増加することによって、
ペレット全体の強度を維持しつつ還元率を向上させるこ
とが可能ではないかとの着想により研究を重ねた結果、
本発明を完成したものである。The present inventors are currently conducting research on improving the strength and reduction rate of reduced pellets, and found that in order to increase the reduction rate, it is sufficient to increase the blending ratio of coke powder, which is the reducing agent in the interior, but if the ratio increases beyond a certain limit, The strength of the reduced pellets decreases and they turn into powder, so by increasing the amount of reducing agent only in the surface layer,
As a result of repeated research, we came up with the idea that it might be possible to improve the reduction rate while maintaining the strength of the entire pellet.
This completes the present invention.
本発明の実施例を第１図、第２図を参照して説明する。An embodiment of the present invention will be described with reference to FIGS. 1 and 2.
第１図は本発明による２重層の生ペレットを製造する模
式１程図である。FIG. 1 is a schematic diagram of a process for producing double-layer green pellets according to the present invention.
先ず微粉鉱石等を収容する原料ホッパーｌからベルトフ
イルダ−４に原料を切出し、同様に還元剤としてのコー
クス粉を収容するコークスホッパー２からベルトフイル
ダー５に、また粘着剤としてのベントナイトを収容する
粘結剤ホッパー３からベルトフイルダー６へそれぞれ所
定量を切り出し、これらはベルトコンベアー７に積替え
られて混線機８に入り、散水配管２４によって混線機８
内に所定量の水が散水され調湿混練される。調湿混練さ
れた主原料、粘結剤、およびコークス粉の混合体はベル
トコンベアー９によりディスクペレタイザー１０に投入
され、ここでも散水配管２３により所定量の散水を受け
て調湿造粒され、所定の強度１粒径、成分を有する内層
生ペレット３０が形成される。形成された内層生ペレッ
ト３０はベルトコンベアー１１によって他のディスクペ
レタイザー１２に供給される。First, the raw material is cut out from the raw material hopper 1 containing fine ore etc. to the belt fielder 4, and similarly from the coke hopper 2 containing coke powder as a reducing agent to the belt fielder 5, and the viscous material containing bentonite as an adhesive. A predetermined amount is cut out from the binder hopper 3 to the belt fielder 6, transferred to the belt conveyor 7, enters the mixer 8, and is transferred to the mixer 8 by the water sprinkling pipe 24.
A predetermined amount of water is sprinkled inside and the mixture is mixed to control the humidity. The mixture of the main raw material, the binder, and the coke powder that has been kneaded at a controlled humidity is fed into a disc pelletizer 10 by a belt conveyor 9, where it is also sprayed with a predetermined amount of water through a water sprinkling pipe 23 to be granulated at a controlled humidity. An inner green pellet 30 having a strength of 1 particle size and composition is formed. The formed inner raw pellets 30 are supplied to another disc pelletizer 12 by a belt conveyor 11.
これと同時に、別系統のコーク粉ホッパー１４からベル
トフイルダ−１７へ所定量のコークス粉が切出され、同
時に粘結剤ホッパー１５からベルトフイルダー１８へベ
ントナイトの所定量が切出され、これらのコークス粉お
よびベントナイトの所定量は、ベルトコンベアー１９に
よって第２の混線機２０に入り、散水配管１３により所
定量の水が散水され、調湿混練された後ベルトコンベア
ー２１により、第２のディスクペレタイザー１２に投入
される。At the same time, a predetermined amount of coke powder is cut out from the coke powder hopper 14 of another system to the belt fielder 17, and at the same time, a predetermined amount of bentonite is cut out from the binder hopper 15 to the belt fielder 18, and these coke powder A predetermined amount of powder and bentonite enters a second mixer 20 by a belt conveyor 19, is sprinkled with a predetermined amount of water by a water sprinkling pipe 13, and after being mixed with controlled humidity, is transferred to a second disc pelletizer 12 by a belt conveyor 21. will be put into the
ディスクペレタイザー１２には予め内層生ペレット３０
が供給されているので、更に散水配管１６から所定量の
散水配管を受け、内層生ペレット３０の外表面全体に、
主原料を含まないコークス粉とベントナイトのみの被覆
材４０を被覆した２重層生ペレット５０が形成される。The disk pelletizer 12 has an inner layer of raw pellets 30 in advance.
is supplied, a predetermined amount of water is further supplied from the water sprinkling pipe 16, and the entire outer surface of the inner raw pellet 30 is coated with water.
A double-layer green pellet 50 is formed, which is coated with a coating material 40 consisting only of coke powder and bentonite, which does not contain any main raw materials.
２重層生ペレット５０は、ディスクペレタイザー１２か
ら排出されてベルトコンベアー２２により、次のグレー
トキルンもしくはロータリーキルン等の還元工程に搬送
されて、予熱、焼成還元工程を経て強度および還元率の
向上した本発明による還元ペレットの製造が完了する。The double-layer raw pellets 50 are discharged from the disc pelletizer 12 and conveyed by a belt conveyor 22 to the next reduction process such as a great kiln or a rotary kiln, and undergo a preheating, firing and reduction process to improve strength and reduction rate of the present invention. The production of reduced pellets is completed.
上記本発明による還元ペレットの製造方法を第１図に示
す実施例について説明したが１次に本発明による配合割
合の限定理由について説明する。The method for producing reduced pellets according to the present invention has been described with reference to the embodiment shown in FIG. 1. First, the reason for limiting the blending ratio according to the present invention will be explained.
内層生ペレット３０の製造において、主原料の微粉鉱石
もしくは酸化物ダストに対し、重量比にて１．６〜２．
４％のベントナイトと、１６％以上のコークス粉を配合
するのは、崩壊しないペレットを形成するためには少く
とも１．６％以上の粘結剤を要するが。２．４％を超す
添加は粘結効果としては飽和するので経済的ではない。In the production of the inner raw pellets 30, the weight ratio of the main raw material, fine ore or oxide dust, is 1.6 to 2.
Blending 4% bentonite and 16% or more coke powder requires at least 1.6% binder to form pellets that do not disintegrate. Addition of more than 2.4% is not economical because the caking effect becomes saturated.
また１６％以上のコークス粉は還元工程において金属と
して還元し内質の健全なペレットを製造するために少く
とも１６％のコークスが必要であって、好ましくは１８
％以上を要するからである。Further, in order to reduce the coke powder containing 16% or more as metal in the reduction process and produce pellets with a sound internal quality, at least 16% coke is required, and preferably 18% coke is required.
% or more is required.
また内層生ペレット３ｏの外側に被覆する被覆材として
は、コークス粉８７〜９５％、ベントナイト１３〜５％
の配合割合に限定すべきであるが、強固な外殻３５を形
成するためには、少くとも５％のベントナイトを必要と
するも１３％を越えると粘結効果が飽和するので経済的
ではない、そのためベントナイトの配合割合を１３〜５
％に限定し、残余をコークス粉として８７〜９５％とし
たものである。さらに被覆材としてコークス粉８７〜９
５％として多くした理由は、内層生ペレット３０として
は還元剤を増加すると還元率は向上するものの、ペレッ
トの強度が低下するので最小限とし、還元工程において
ペレット表層への被覆材からのＣの含浸による補填を図
り還元率の向上を図ったものである。In addition, the coating material to be coated on the outside of the inner layer raw pellets 3o is 87 to 95% coke powder and 13 to 5% bentonite.
However, in order to form a strong outer shell 35, at least 5% of bentonite is required, but if it exceeds 13%, the caking effect is saturated and it is not economical. Therefore, the blending ratio of bentonite is 13 to 5.
%, with the remainder being 87-95% as coke powder. In addition, coke powder 87-9 is used as a coating material.
The reason for increasing the amount to 5% is that although increasing the reducing agent for the inner layer raw pellet 30 improves the reduction rate, the strength of the pellet decreases, so it should be kept to a minimum, and in order to reduce the amount of C from the coating material on the pellet surface layer in the reduction process. This is an attempt to improve the reduction rate by compensating through impregnation.
次に内層生ペレット３０に対し、被覆材４０の配合割合
を重量比にて３〜１０％とした理由は、還元ペレット製
品の表層に粘結剤の多い強固な外殻３５を形成し、ペレ
ット強度を増加させるには少くとも被覆材４０が３％以
上を必要とするも、１０％を越すとその効果が飽和しコ
ストの上昇を来たし不経済となるからである。効果的な
被覆材の割合は５〜８％が好適である。Next, the reason why the blending ratio of the coating material 40 to the inner raw pellet 30 was set at 3 to 10% by weight is to form a strong outer shell 35 with a large amount of binder on the surface layer of the reduced pellet product, and to In order to increase the strength, at least 3% or more of the coating material 40 is required, but if it exceeds 10%, the effect will be saturated and the cost will increase, making it uneconomical. The effective coating percentage is preferably between 5 and 8%.
本発明による生ペレツト製造に際しては、先ず主原料の
鉱石粉等に対し、重量比で１．６〜２．４％のベントナ
イト、および１６％以上のコークスという最小限の粘結
剤およびコークス量として内層生ペレット３０を製造し
、これによりコストの上昇を最小限に抑制すると共に、
内層生ペレット４０の外側にコークス粉８７〜９５％、
ベントナイト１３〜５％のみの被覆材４０を内部の内層
生ペレットに対して重量費にて３〜１０％まぶしてコー
クス粉、ベントナイトのみの被覆層を形成して２重層ペ
レット５０とする構成をとったので次工程の予熱、焼成
、還元工程を修了した還元ペレット成品に次の如き作用
を有するのが特徴である。When producing green pellets according to the present invention, first, the minimum amount of binder and coke is 1.6 to 2.4% by weight of bentonite and 16% or more of coke to the main raw material such as ore powder. Producing inner raw pellets 30, thereby minimizing cost increases,
87 to 95% coke powder on the outside of the inner raw pellet 40,
A coating material 40 containing only 13 to 5% bentonite is sprinkled on the inner layer raw pellets at 3 to 10% by weight to form a coating layer consisting only of coke powder and bentonite to form a double layer pellet 50. Therefore, the reduced pellet product that has completed the next steps of preheating, firing, and reduction steps is characterized by having the following effects.
（イ）被覆層はベントナイトとコークス粉のみであるの
で、内層ペレットの表層に粘結剤の多い強度大なる外殻
３５が形成され、高炉装入等においても崩壊することが
ない。(a) Since the coating layer is only made of bentonite and coke powder, a strong outer shell 35 containing a large amount of binder is formed on the surface layer of the inner pellet, and does not collapse even when charged into a blast furnace.
（ロ）被覆層はコークス８７〜９５％、ベントナイト１
３〜５％のコークス主体の配合であるので、還元工程に
おいて、そのＣ質が内部の内層ペレットに侵入するので
、たとえ内肩ペレットのコークス粉が最小限であっても
還元するコークス量および発生熱量としては２重層ペレ
ット５０全体として十分であり、還元作用にはなんらの
支障をも来たさず、高い還元率を上げることができた。(b) The coating layer is 87-95% coke and 1 bentonite.
Since the composition is mainly composed of 3 to 5% coke, the carbon content invades the internal inner layer pellet during the reduction process, so even if the coke powder in the inner shoulder pellet is minimal, the amount of coke to be reduced and the amount of coke generated will be reduced. The amount of heat was sufficient for the double layer pellet 50 as a whole, and a high reduction rate could be achieved without any hindrance to the reduction action.
還元ペレットの製造において、還元率の上昇を図ろうと
すれば、還元剤コークス量の配合割合の多い生ペレット
を製造すればよいが、コークス量が過多の場合には強度
が低下するので、この矛盾を本発明は２層構造の生ペレ
ットを製造することにより解決したもので、内層生ペレ
ット３０の粘結剤、コークス量を最少限として、その不
足を被覆材４０によって補填する構成をとったので、次
の如き効果を挙げることができた。In the production of reduced pellets, if you want to increase the reduction rate, you can produce green pellets with a high blending ratio of reducing agent coke, but if the amount of coke is too large, the strength will decrease, so this contradiction arises. The present invention solves this problem by manufacturing green pellets with a two-layer structure, and has a structure in which the amount of binder and coke in the inner layer green pellets 30 is minimized, and the shortage is compensated for by the coating material 40. , the following effects were achieved.
（イ）還元工程における還元率は従来法による場合は７
５％であったが１本発明ペレットは７９％と著しく向上
させることができた。(b) The reduction rate in the reduction process is 7 when using the conventional method.
5%, but one pellet of the present invention was able to significantly improve it to 79%.
（ロ）被覆材４０としては主原料を含まないコークス粉
８７〜９５％、ベントナイト１３〜５％の配合割合とし
て、これを内層生ペレット３０に対して重量比で３〜１
０％被覆したので、２重層生ペレット５０としては表層
に粘結剤が多く配合され、これが焼成還元により強固な
外殻３５が形成されているので、還元ペレット成品の一
１論の粉発生割合を以て表わす粉率（％）は、従来法で
は１．０％であるのに対し、本発明品は０．７％と低減
させることができた。(b) The coating material 40 is a blending ratio of 87 to 95% coke powder that does not contain the main raw materials and 13 to 5% bentonite, and the weight ratio of this to the inner raw pellet 30 is 3 to 1.
Since the double-layer green pellet 50 is coated with 0% coating, a large amount of binder is mixed on the surface layer, and this is reduced by firing to form a strong outer shell 35, so that the powder generation rate of the reduced pellet product is as follows. The powder ratio (%), expressed as , was 1.0% in the conventional method, whereas it was able to be reduced to 0.7% in the product of the present invention.
（ハ）被覆層形成に要する費用は多少増加するものの、
粘結剤ベンナイトおよび還元剤コークス粉の効果的配合
により材料費が従来より低減し、還元率の向上、粉率の
低減効果により償って余りある経済的効果を挙げること
ができた。(c) Although the cost required to form the coating layer will increase somewhat,
The effective combination of benite as a binder and coke powder as a reducing agent lowers the material cost compared to the conventional method, and the improved reduction rate and reduction in powder ratio have more than compensated for the economic effects.
（ニ）本発明の生ペレットの製造方法は、微粉鉄鉱石の
みならず、クロム鉱石その他の鉱石の造粒に有効に適用
し得る。(d) The method for producing green pellets of the present invention can be effectively applied to the granulation of not only fine iron ore but also chromium ore and other ores.
第１図は本発明による２層構造の生ペレットの製造工程
の実施例を示す模式製造工程図、第２図（Ａ）、（Ｂ）
、（Ｃ）は本発明による生ペレットの構成および作用を
示す模式断面図であって、（Ａ）は内層生ペレット、（
Ｂ）は２層構造の本発明による生ペレット（Ｃ）は焼成
、還元工程における被覆材中のＣの内層ペレットへの含
浸作用を示す図である。
１・・・・・・・・・・・・・・・原料ホッパー２．１
４・・・・・・コークス粉ホッパー３．１５・・・・・
・粘着剤ホッパー
４．５．６．１７．１８・・・・・・ベルトフイルダ−
７，９，１１，１９，２１・・・ベルトコンベアー８・
・・・・・・・・・・・・・・混練機１ｏ、１２・・・
・・・ディスクペレタイザー１３．１６・・・・・・散
水配管Figure 1 is a schematic manufacturing process diagram showing an example of the manufacturing process of two-layer raw pellets according to the present invention, and Figures 2 (A) and (B)
, (C) are schematic cross-sectional views showing the structure and function of the raw pellet according to the present invention, (A) is the inner layer raw pellet, (
B) is a diagram illustrating the impregnation effect of C in the coating material on the inner layer pellet of the raw pellet (C) of the present invention having a two-layer structure during the firing and reduction steps. 1・・・・・・・・・・・・・・・Raw material hopper 2.1
4...Coke powder hopper 3.15...
・Adhesive hopper 4.5.6.17.18...Belt fielder
7, 9, 11, 19, 21... Belt conveyor 8.
...... Kneading machine 1o, 12...
...Disc pelletizer 13.16 ...Water piping
Claims (1)
結剤および炭素質材料を混合した後造粒して生ペレット
を製造する工程と、前記生ペレットを還元炉に装入して
予熱、焼成後還元雰囲気で還元する工程と、を有して成
る還元ペレットの製造方法において、前記主原料に重量
比にて１．６〜２．４％のベントナイトと１６％以上の
コークス粉を調質混練した後造粒して内層生ペレットを
形成する段階と、前記内層生ペレットの外側に重量比に
てコークス粉８７〜９５％、粘結剤１３〜５％より成る
粉状被覆材を前記内層生ペレットに対し重量比にて３〜
１０％被覆して外層を形成する段階と、より成る前記生
ペレットの製造工程を有することを特徴とする還元ペレ
ットの製造方法。(1) A process of mixing a binder and a carbonaceous material with the main raw material, fine ore or oxide dust, and then granulating it to produce green pellets; charging the raw pellets into a reduction furnace and preheating; A method for producing reduced pellets comprising the step of reducing in a reducing atmosphere after firing, wherein the main raw material is tempered with 1.6 to 2.4% bentonite and 16% or more coke powder by weight. A step of kneading and granulating to form inner layer green pellets, and applying a powder coating material consisting of 87 to 95% coke powder and 13 to 5% binder by weight on the outside of the inner layer green pellets, the inner layer is kneaded and then granulated. Weight ratio of 3 to raw pellets
A method for producing reduced pellets, comprising a step of forming an outer layer by coating 10%, and a step of producing the green pellets.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29151990A JPH04165025A (en) | 1990-10-29 | 1990-10-29 | Manufacture of reduced pellet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29151990A JPH04165025A (en) | 1990-10-29 | 1990-10-29 | Manufacture of reduced pellet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04165025A true JPH04165025A (en) | 1992-06-10 |
Family
ID=17769949
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29151990A Pending JPH04165025A (en) | 1990-10-29 | 1990-10-29 | Manufacture of reduced pellet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04165025A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002036836A1 (en) * | 2000-10-30 | 2002-05-10 | Nippon Steel Corporation | Metal oxide-containing green pellet for reducing furnace, method for production thereof, method for reduction thereof, and reduction facilities |
| KR100627448B1 (en) * | 1999-11-23 | 2006-09-25 | 주식회사 포스코 | A method for coating cold bonded pellet by using cdq dust |
| JP2006316333A (en) * | 2005-05-16 | 2006-11-24 | Nippon Steel Corp | Zinc-containing dust pellet, and zinc recovering method using the same |
| JP2012201947A (en) * | 2011-03-25 | 2012-10-22 | Sumitomo Metal Mining Co Ltd | Raw material pellet for reduction-roasting of steel dust, and method of manufacturing the same |
-
1990
- 1990-10-29 JP JP29151990A patent/JPH04165025A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100627448B1 (en) * | 1999-11-23 | 2006-09-25 | 주식회사 포스코 | A method for coating cold bonded pellet by using cdq dust |
| WO2002036836A1 (en) * | 2000-10-30 | 2002-05-10 | Nippon Steel Corporation | Metal oxide-containing green pellet for reducing furnace, method for production thereof, method for reduction thereof, and reduction facilities |
| US7815710B2 (en) | 2000-10-30 | 2010-10-19 | Nippon Steel Corporation | Metal oxide-containing green pellet for reducing furnace, method for production thereof, method of reduction thereof, and reduction facilities |
| US7964014B2 (en) | 2000-10-30 | 2011-06-21 | Nippon Steel Corporation | Metal oxide-bearing green pellets for reducing furnace, method of production of same, method of reduction of same, and reduction facility |
| JP2006316333A (en) * | 2005-05-16 | 2006-11-24 | Nippon Steel Corp | Zinc-containing dust pellet, and zinc recovering method using the same |
| JP2012201947A (en) * | 2011-03-25 | 2012-10-22 | Sumitomo Metal Mining Co Ltd | Raw material pellet for reduction-roasting of steel dust, and method of manufacturing the same |
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