JPH01168824A - Production of reduced ore pellet - Google Patents

Production of reduced ore pellet

Info

Publication number
JPH01168824A
JPH01168824A JP32519387A JP32519387A JPH01168824A JP H01168824 A JPH01168824 A JP H01168824A JP 32519387 A JP32519387 A JP 32519387A JP 32519387 A JP32519387 A JP 32519387A JP H01168824 A JPH01168824 A JP H01168824A
Authority
JP
Japan
Prior art keywords
pellet
reduced
calcium chloride
ore
pellets
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
Application number
JP32519387A
Other languages
Japanese (ja)
Inventor
Haruo Kokubu
国分 春生
Toshihiro Inatani
稲谷 稔宏
Katsuhide Kobayashi
小林 且英
Katsuyoshi Fukamizu
深水 勝義
Teiichi Yamada
山田 禎一
Nobutake Kasashima
笠島 信武
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.)
JFE Steel Corp
Kawasaki Kogyo KK
Original Assignee
Kawasaki Kogyo KK
Kawasaki Steel Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kawasaki Kogyo KK, Kawasaki Steel Corp filed Critical Kawasaki Kogyo KK
Priority to JP32519387A priority Critical patent/JPH01168824A/en
Publication of JPH01168824A publication Critical patent/JPH01168824A/en
Pending legal-status Critical Current

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  • Manufacture And Refinement Of Metals (AREA)

Abstract

PURPOSE:To improve reduction ratio of pellet by containing calcium chloride in the pellet at the time of drying, heating and reducing ore-contained green pellet in a reduction furnace. CONSTITUTION:The finder and water having prescribed ratio are added to chromium ore and coke crushed at the prescribed grain size and kneaded with a pug mill 7, and humidity conditioning and pelletizing are executed with a disk pelletizer 1, to form the green pellet having 10-15mm size (about 15-17wt.% carbon content). This green pellet is conveyed with grate conveyor 3 and dried and heated with a pre-heater 2 and sent into a rotary kiln 4 and reduced by heating with a burner 6 and cooled with a cooler 5, to make the reduced chromium ore pellet. Then, the calcium chloride is beforehand added to the green pellet at about 0.1-0.5wt.% as CaCl2. By this method, the reduction ratio of the reduced chromium ore pellet is improved, and many kinds of unit consumptions at the stainless steel blowing process in a converter are reduced and blowing time is shortened and the productivity, etc., is improved.

Description

【発明の詳細な説明】 〔産業上の利用分野] 本発明は、鉱石を含有するグリーンペレットを、予熱機
とロータリーキルンとを連設した還元炉で乾燥・加熱・
還元して、還元鉱石ペレットを製造する方法に関するも
のである。
[Detailed Description of the Invention] [Industrial Application Field] The present invention involves drying, heating, and drying green pellets containing ore in a reduction furnace equipped with a preheater and a rotary kiln.
The present invention relates to a method for producing reduced ore pellets by reduction.

〔従来の技術] 予熱機とロータリーキルンを連設した還元炉を用いて、
還元クロム鉱石ペレットを製造するプロセスフローシー
トの一例を第4図に示す。
[Conventional technology] Using a reduction furnace with a preheater and a rotary kiln,
An example of a process flow sheet for producing reduced chromium ore pellets is shown in FIG.

先ず所定の粒度まで粉砕されたクロム鉱石とコークスに
少量の粘結材、例えばベントナイトを所定の割合で加え
、混JiiIi機、例えばパグミル7で水分を8〜9重
量%程度まで加えて混呻したものを、ディスクペレタイ
ザー1で調湿・造粒してlO〜15mm程度のグリーン
ペレットとする。
First, a small amount of a caking agent, such as bentonite, was added to chromium ore and coke that had been crushed to a predetermined particle size in a predetermined ratio, and water was added to about 8 to 9% by weight in a mixing machine such as Pug Mill 7, and the mixture was mixed. The material is humidified and granulated using a disc pelletizer 1 to form green pellets of about 10 to 15 mm.

ここで内装炭材であるコークスは、クロム鉱石中のCr
、Feの酸化物を金属に還元する当量を添5加するのが
一般的であり、グリーンペレット中の炭素含有量は15
〜17重量%、程度である。
Here, the coke that is the interior carbon material is Cr in the chromium ore.
, it is common to add 5 equivalents to reduce Fe oxide to metal, and the carbon content in green pellets is 15
It is about 17% by weight.

造粒されたグリーンペレットは、予熱機2でグレートコ
ンベア3によって搬送されながら乾燥・加熱される。予
熱機2は通常3室に別れており。
The granulated green pellets are dried and heated in a preheater 2 while being conveyed by a great conveyor 3. Preheater 2 is usually divided into three chambers.

ガス温度は例えば第3室は220℃、鞭2室は550℃
、第1室は1000℃となっており、特に第1室はロー
タリーキルン4からの燃焼排ガスが、破線矢印で示すよ
うに直接入り込む室であるため、ガス温度が最も高い。
The gas temperature is, for example, 220℃ in the third chamber and 550℃ in the whip second chamber.
The temperature of the first chamber is 1000° C. In particular, the combustion exhaust gas from the rotary kiln 4 directly enters the first chamber as shown by the broken line arrow, so the gas temperature is the highest.

予熱機2で予熱されたペレットは高温のロータリーキル
ン4内に入り、バーナ6により加熱され、内装炭材によ
り還元されたのち、クーラー5で冷却されて製品である
還元クロム鉱石ペレットとなる。
The pellets preheated by a preheater 2 enter a high-temperature rotary kiln 4, are heated by a burner 6, are reduced by an internal carbon material, and are then cooled by a cooler 5 to become reduced chromium ore pellets as a product.

しかし、ロータリーキルン4の燃焼排ガス組成は1例え
ばH2O:15.6容量%、GO2:13.5容量%、
CO:4.1容量%、N2:66.8容量%のように酸
化性ガス(GO2+I(20)を約30容量%含んでお
り、かつガス温度が約t ooo℃と高温であるため、
予熱機2の第1室においてペレット表層部に存在する炭
材がC+ 820 = G O+ H2 C+C02=2GO の反応によって脱炭される。この量は一般に全内装炭材
の約20重量%にも達するため、従来のプロセスでは還
元鉱石ペレットの還元率80%の達成が限界であった。
However, the combustion exhaust gas composition of the rotary kiln 4 is 1, for example, H2O: 15.6% by volume, GO2: 13.5% by volume,
CO: 4.1% by volume, N2: 66.8% by volume, which contains about 30% by volume of oxidizing gas (GO2+I(20)), and the gas temperature is as high as about 20°C.
In the first chamber of the preheater 2, the carbonaceous material present in the surface layer of the pellet is decarburized by the reaction C+820=GO+H2C+C02=2GO. Since this amount generally reaches about 20% by weight of the total carbonaceous material, conventional processes have reached the limit of achieving a reduction rate of 80% for reduced ore pellets.

この予熱機内でのペレットからの脱炭抑制対策について
は、従来から決め手が無く、脱炭反応で失われる炭素量
を補うよう内装炭材の配合比率を上昇させることで対処
していたが、内装炭材の増配は顕著にペレットの強度を
低下させ粉率の上昇を招くという致命的な欠点を有して
おり、還元クロム鉱石ペレット以外の還元鉱石ペレット
の製造方法においても同様であった。
Conventionally, there was no decisive measure to suppress decarburization from pellets in the preheating machine, and the solution was to increase the blending ratio of the interior carbon material to compensate for the amount of carbon lost in the decarburization reaction. Increasing the amount of carbonaceous material has the fatal disadvantage of significantly lowering the strength of the pellets and increasing the powder ratio, and this also applies to methods for producing reduced ore pellets other than reduced chromium ore pellets.

[発明が解決しようとする問題点1 本発明は、還元鉱石ペレットの強度低下、粉率上昇とい
った問題を引き起すことなしに、予熱機内での脱炭量を
最少限に抑制する方法を提供し、還元鉱石ペレットの還
元率の飛躍的向上を可能ならしめることを目的とするも
のである。
[Problem to be Solved by the Invention 1] The present invention provides a method for minimizing the amount of decarburization in a preheater without causing problems such as a decrease in the strength of reduced ore pellets and an increase in powder ratio. The purpose is to make it possible to dramatically improve the reduction rate of reduced ore pellets.

【問題点を解決するための手段J 本発明者らは、上記従来技術の問題点を解決すべく研究
を重ねた結果、前記グリーンペレットに塩化カルシウム
を含有させると、該ペレットが強度低下および粉率上昇
を招かず、脱炭率を低下させ還元率を向上させ得る知見
を得1本発明に到達したものである。
[Means for Solving the Problems J] As a result of repeated research in order to solve the above-mentioned problems of the prior art, the present inventors have found that when calcium chloride is added to the green pellets, the strength of the green pellets decreases and the pellets become powdery. The present invention was achieved by obtaining the knowledge that it is possible to reduce the decarburization rate and improve the reduction rate without causing an increase in the decarburization rate.

〔作用] 本発明を、鉱石としてクロム鉱石を用いた場合を例とし
て説明する。
[Operation] The present invention will be explained using an example in which chromium ore is used as the ore.

クロム鉱石=79重量部 コークス=18重量部 ベントナイト:3重量部 からなる配合原料に対し、塩化カルシウムなCaCβ2
として0.1〜1.0重量%添加し、直径10mmのグ
リーンペレットとし、塩化カルシウム添加率と脱炭率、
予熱ペレット強度および還元率との関係を試験した。
Chromium ore = 79 parts by weight Coke = 18 parts by weight Bentonite: For the blended raw material consisting of 3 parts by weight, calcium chloride CaCβ2
Add 0.1 to 1.0% by weight as green pellets with a diameter of 10 mm, and calculate the calcium chloride addition rate and decarburization rate.
The relationship between preheated pellet strength and reduction rate was tested.

第1図に、1000℃でCO2: 30容量%、N2ニ
ア’0容量%雰囲気下に上記グリーンペレットを60分
間放置した場合の脱炭率と塩化カルシウム添加率との関
係を示す、塩化カルシウム0.1重量%以上の添加で脱
炭率が顕著に低下するが、0.5重量%以上添加しても
、それ以上の効果は得られ雇い。
Figure 1 shows the relationship between the decarburization rate and the calcium chloride addition rate when the green pellets were left for 60 minutes in an atmosphere of 30% CO2 and 0% N2 by volume at 1000°C. The decarburization rate decreases markedly when adding .1% by weight or more, but even greater effects can be obtained even when adding 0.5% by weight or more.

この試験結果より、予熱機内での脱炭抑制には、塩化カ
ルシウムの最大0.5重量%までの添加で十分効果が得
られることが分かる。
The test results show that adding up to 0.5% by weight of calcium chloride is sufficient to suppress decarburization in the preheater.

第2図に、900℃でN2雰囲気下に40分間放置した
場合の、ペレット各個の強度と塩化カルシウム添加率と
の関係を示す、塩化カルシウム0.5重量%までの添加
ではペレット強度に殆ど変化は見られず、0.7重量%
以上の添加では強度が低下するようである。
Figure 2 shows the relationship between the strength of each pellet and the addition rate of calcium chloride when left in a N2 atmosphere at 900°C for 40 minutes. Addition of calcium chloride up to 0.5% by weight causes almost no change in pellet strength. is not observed, 0.7% by weight
It seems that the strength decreases when the above amount is added.

第3図に1000℃でCO2:30容量%、N2ニア0
容量%雰囲気下に60分保持後、N2雰囲気に切換え1
300℃に昇温し45分間保持した場合の、還元率と塩
化カルシウム添加率との関係を示す、塩化カルシウムの
添加で還元率が向上するが、0.5重量%以上添加して
もそれ以上の効果は得られない。
Figure 3 shows CO2: 30% by volume and N2 near 0 at 1000℃.
After holding the volume% atmosphere for 60 minutes, switch to N2 atmosphere 1
The relationship between the reduction rate and the addition rate of calcium chloride is shown when the temperature is raised to 300°C and held for 45 minutes.The reduction rate improves with the addition of calcium chloride, but even if it is added at 0.5% by weight or more, it does not increase. effect cannot be obtained.

塩化カルシウムが上記の効果を示す理由は詳かではない
が、塩素系ガスによるグリーンペレットの酸化性ガスか
らの保護効果によるものと思われる。
Although the reason why calcium chloride exhibits the above effect is not clear, it is thought to be due to the effect of protecting the green pellets from oxidizing gases by chlorine gas.

還元鉱石ペレットにおける塩化カルシウム添加の効果は
、クロム鉱石以外の鉱石についてもほぼ同様に得ること
ができる。
The effect of adding calcium chloride to reduced ore pellets can be obtained in substantially the same way with ores other than chromium ore.

〔実施例J クロム鉱石ニア9重量部 コークス:18重量部 ベントナイト:3重量部 からなる配合原料を用い、配合原料に対するCaCβ2
として0.3重量%の塩化カルシウムを水溶液としてパ
グミル内の配合原料に添加し、配合原料を加湿・混練し
たのちディスクペレタイザーで調湿・造粒してグリーン
ペレットとなし。
[Example J Using a blended raw material consisting of 9 parts by weight of chromium ore nia, 18 parts by weight of coke, and 3 parts by weight of bentonite, CaCβ2 relative to the blended raw material was used.
0.3% by weight of calcium chloride was added as an aqueous solution to the raw materials in the pug mill, and the raw materials were humidified and kneaded, then humidified and granulated using a disk pelletizer to form green pellets.

グリーンペレットを下記操業条件にて乾燥・加熱・還元
し、塩イ7ヒカルシウム無添加時の比較例とともに、還
元率および一5mm粉率を第1表に示した。
The green pellets were dried, heated, and reduced under the following operating conditions, and the reduction rate and the -5 mm powder rate are shown in Table 1, along with a comparative example in which calcium salt was not added.

第   1   表 塩化カルシウムの添加により、約5%の還元率向上効果
が得られ、かつ粉率の増加は認められなかった。
Table 1 By adding calcium chloride, an effect of improving the reduction rate by about 5% was obtained, and no increase in the powder ratio was observed.

[発明の効果] 本発明の方法により、還元鉱石ペレットの還元率が向上
し1例えば還元クロム鉱石ペレットの還元率向上は、転
炉でのステンレス吹錬工程での各檜原単位削減、吹錬時
間の短縮による生産性の向上など本発明の有用性は極め
て大きく、本発明は還元クロム鉱石ペレットのみでなく
、他の還元鉱石ペレットの製造においても有効である。
[Effects of the Invention] The method of the present invention improves the reduction rate of reduced ore pellets.1 For example, the improvement of the reduction rate of reduced chromium ore pellets reduces the unit consumption of each cypress in the stainless steel blowing process in a converter, and reduces the blowing time. The usefulness of the present invention is extremely large, such as the improvement of productivity by shortening the time, and the present invention is effective not only in the production of reduced chromium ore pellets but also in the production of other reduced ore pellets.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は塩化カルシウム添加率と脱炭率との関係を示す
グラフ、第2図は塩化カルシウム添加率と予熱ペレット
強度との関係を示すグラフ、第3図は塩化カルシウム添
加率と還元率との関係を示すグラフ、第4図は還元クロ
ム鉱石ペレットを製造するプロセスフローシートの一例
を示す図である。 l・−・デスクペレタイザー 2・・・予a1m      3・・・グレートコンベ
ヤ4・・・ロータリーキルン 5・・・クーラー    6・・・バーナー7・・・パ
グミル    8・・・キルン排ガス出゛願人 川崎製
鉄株式会社 川鉄鉱業株式会社
Figure 1 is a graph showing the relationship between calcium chloride addition rate and decarburization rate, Figure 2 is a graph showing the relationship between calcium chloride addition rate and preheated pellet strength, and Figure 3 is a graph showing the relationship between calcium chloride addition rate and reduction rate. FIG. 4 is a diagram showing an example of a process flow sheet for producing reduced chromium ore pellets. l... Desk pelletizer 2... Reserve area 1m 3... Great conveyor 4... Rotary kiln 5... Cooler 6... Burner 7... Pug mill 8... Kiln exhaust gas applicant Kawasaki Steel Kawatetsu Mining Co., Ltd.

Claims (1)

【特許請求の範囲】 1 鉱石を含有するグリーンペレットを、予熱機とロー
タリーキルンとを連設した還元炉を用いて乾燥・加熱・
還元する方法において、該グリーンペレットに塩化カル
シウムを含有させたことを特徴とする還元鉱石ペレット
の製造方法。 2 鉱石がクロム鉱石であることを特徴とする特許請求
の範囲第1項に記載の還元鉱石ペレットの製造方法。
[Claims] 1 Green pellets containing ore are dried, heated, and
A method for producing reduced ore pellets, characterized in that the green pellets contain calcium chloride. 2. The method for producing reduced ore pellets according to claim 1, wherein the ore is chromium ore.
JP32519387A 1987-12-24 1987-12-24 Production of reduced ore pellet Pending JPH01168824A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP32519387A JPH01168824A (en) 1987-12-24 1987-12-24 Production of reduced ore pellet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP32519387A JPH01168824A (en) 1987-12-24 1987-12-24 Production of reduced ore pellet

Publications (1)

Publication Number Publication Date
JPH01168824A true JPH01168824A (en) 1989-07-04

Family

ID=18174053

Family Applications (1)

Application Number Title Priority Date Filing Date
JP32519387A Pending JPH01168824A (en) 1987-12-24 1987-12-24 Production of reduced ore pellet

Country Status (1)

Country Link
JP (1) JPH01168824A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017063250A1 (en) * 2015-10-14 2017-04-20 福建鼎信实业有限公司 Production method for hot-delivering oxidized pellets in shaft furnace to sealed ferrochrome electric furnace
RU2630405C2 (en) * 2015-10-29 2017-09-07 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Сибирский государственный индустриальный университет" Pellet heat treatment method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017063250A1 (en) * 2015-10-14 2017-04-20 福建鼎信实业有限公司 Production method for hot-delivering oxidized pellets in shaft furnace to sealed ferrochrome electric furnace
RU2630405C2 (en) * 2015-10-29 2017-09-07 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Сибирский государственный индустриальный университет" Pellet heat treatment method

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