JP2595549B2 - Melt reduction method of Cr raw material - Google Patents
Melt reduction method of Cr raw materialInfo
- Publication number
- JP2595549B2 JP2595549B2 JP62201002A JP20100287A JP2595549B2 JP 2595549 B2 JP2595549 B2 JP 2595549B2 JP 62201002 A JP62201002 A JP 62201002A JP 20100287 A JP20100287 A JP 20100287A JP 2595549 B2 JP2595549 B2 JP 2595549B2
- Authority
- JP
- Japan
- Prior art keywords
- blown
- secondary combustion
- blowing
- reduction
- ore
- 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
Links
- 230000009467 reduction Effects 0.000 title claims description 56
- 238000000034 method Methods 0.000 title claims description 21
- 239000002994 raw material Substances 0.000 title claims description 15
- 238000002485 combustion reaction Methods 0.000 claims description 54
- 239000002184 metal Substances 0.000 claims description 54
- 229910052751 metal Inorganic materials 0.000 claims description 54
- 238000007664 blowing Methods 0.000 claims description 48
- 239000007789 gas Substances 0.000 claims description 43
- 239000002893 slag Substances 0.000 claims description 42
- 238000003723 Smelting Methods 0.000 claims description 19
- 239000003575 carbonaceous material Substances 0.000 claims description 12
- 238000005261 decarburization Methods 0.000 claims description 6
- 239000011261 inert gas Substances 0.000 claims description 5
- 239000000155 melt Substances 0.000 claims description 4
- 230000001603 reducing effect Effects 0.000 claims description 4
- 238000006722 reduction reaction Methods 0.000 description 53
- 238000007796 conventional method Methods 0.000 description 15
- 238000012545 processing Methods 0.000 description 9
- 238000012546 transfer Methods 0.000 description 9
- 238000003756 stirring Methods 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 6
- 239000000571 coke Substances 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- 230000009471 action Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 230000004907 flux Effects 0.000 description 4
- 238000011946 reduction process Methods 0.000 description 4
- 239000002253 acid Substances 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- ZPUCINDJVBIVPJ-LJISPDSOSA-N cocaine Chemical compound O([C@H]1C[C@@H]2CC[C@@H](N2C)[C@H]1C(=O)OC)C(=O)C1=CC=CC=C1 ZPUCINDJVBIVPJ-LJISPDSOSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000007667 floating Methods 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000011819 refractory material Substances 0.000 description 2
- 229910000604 Ferrochrome Inorganic materials 0.000 description 1
- 102000004316 Oxidoreductases Human genes 0.000 description 1
- 108090000854 Oxidoreductases Proteins 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 239000003610 charcoal Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000012733 comparative method Methods 0.000 description 1
- 239000000112 cooling gas Substances 0.000 description 1
- 230000002079 cooperative effect Effects 0.000 description 1
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- 230000007423 decrease Effects 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
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- 238000003672 processing method Methods 0.000 description 1
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- 238000009834 vaporization Methods 0.000 description 1
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Landscapes
- Manufacture And Refinement Of Metals (AREA)
- Manufacture Of Iron (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、Cr鉱石やCr鉱ペレツト等のCr原料の溶融還
元方法に関する。The present invention relates to a method for smelting and reducing Cr raw materials such as Cr ore and Cr ore pellets.
従来、ステンレス鋼等の高Cr鋼は、Cr鉱石から製造さ
れたフエロクロムを原料として溶製されてきた。このよ
うな従来の方法に対し、最近、省エネルギー、低製造コ
ストの観点から、Cr鉱石等のCr原料（以下、Cr鉱石を例
に説明する）から直接高Cr溶銑を得る、所謂溶融還元法
が注目を集めている。この溶融還元法は、還元炉にCr鉱
石、炭材等を投入し、Crを還元して直接高Cr溶銑を得る
ものである。Conventionally, high Cr steel such as stainless steel has been melted using ferrochrome produced from Cr ore as a raw material. In contrast to such a conventional method, a so-called smelting reduction method for obtaining high Cr hot metal directly from a Cr raw material such as Cr ore (hereinafter, Cr ore is described as an example) has recently been proposed from the viewpoint of energy saving and low production cost. Attracting attention. In this smelting reduction method, Cr ore, carbonaceous material and the like are charged into a reduction furnace, and Cr is reduced to directly obtain high Cr hot metal.
この溶融還元法として、従来いくつかの方式が提案さ
れているが、そのうちの１つとして、ランスからのO2上
吹きとともに、底吹き羽口からO2、横吹き羽口からN2を
それぞれ吹き込む方法、或いはランスからのO2上吹きと
ともに、底吹き羽口からO2、横吹き羽口からO2及びN2を
それぞれ吹き込む方法が知られている。例えば、後者の
例としては特開昭61−279608号をあげることができる。As the smelting reduction method, some conventional methods have been proposed, as one of them, O 2 top-blown with from the lance, the bottom tuyeres O 2, from the side tuyeres N 2, respectively method of blowing, or O 2 top blowing with from the lance, O 2 from the bottom tuyeres, a method of blowing from the side blowing tuyeres O 2 and N 2, respectively are known. For example, JP-A-61-279608 is an example of the latter.
しかし、これら従来の方法はいずれもCrの還元速度が
小さく、処理に時間がかかるという大きな問題がある。
この背景には以下のような点をあげることができる。However, each of these conventional methods has a serious problem that the reduction rate of Cr is low and the processing takes time.
This can be explained by the following points.
従来、炉内におけるCr鉱石の還元はスラグ中でCr鉱石
が溶解した後、炭材のＣが作用することにより進行する
ものであつて、Cr鉱石の溶融がCr還元の律速であると考
えられ、このため処理時間を短縮するための主要な技術
的関心は、スラグ組成の特定等の点に向けられていた。
しかし、Cr鉱石は基本的に難溶融性であり、Cr鉱石の溶
融を促進して還元速度を高めることには限界がある。Conventionally, the reduction of Cr ore in the furnace proceeds by the action of C on the carbonaceous material after the dissolution of the Cr ore in the slag, and it is considered that the melting of the Cr ore is the rate-limiting rate of Cr reduction. Therefore, major technical interest in shortening the processing time has been directed to the identification of the slag composition and the like.
However, Cr ore is basically difficult to melt, and there is a limit in promoting the melting of Cr ore to increase the reduction rate.
Cr鉱石のスラグ中での溶融速度を上げCr鉱石の還元処
理速度を向上させるため、炉内のCOガスを二次燃焼さ
せ、その熱を利用するという方法が考えられ、従来でも
炉上部壁から二次燃焼用O2を吹き込む方法が採られてい
る。しかし従来では、二次燃焼比を上げると排ガス温度
は上昇するものの、排ガス顕熱を効率よく溶湯へ伝達さ
せる技術がなく、この結果、着熱効率が低下し、高温排
ガスを排出せざるを得ない。そして、このような高温排
ガスは炉内壁耐火物や排ガスフードの耐火物を激しく損
耗させるという大きな問題があり、このため二次燃焼比
はあまり上げられないというのが一般的な考え方であつ
た。In order to increase the melting rate of Cr ore in slag and increase the reduction rate of Cr ore, secondary combustion of CO gas in the furnace and the use of that heat have been considered. a method of blowing secondary combustion O 2 is adopted. However, conventionally, although the exhaust gas temperature rises when the secondary combustion ratio is increased, there is no technology for efficiently transmitting the sensible heat of the exhaust gas to the molten metal, and as a result, the heat transfer efficiency is reduced and the high-temperature exhaust gas has to be discharged. . Such high-temperature exhaust gas has a serious problem that the refractory inside the furnace wall and the refractory of the exhaust gas hood are severely worn. Therefore, it is a general idea that the secondary combustion ratio cannot be increased so much.
このような従来の認識に対し、本発明者等は溶融還元
のメカニズム及びこれに対応した具体的な手段について
検討を重ねたものであり、この結果、次のような事実を
見い出した。In response to such conventional recognition, the present inventors have repeatedly studied the mechanism of smelting reduction and specific means corresponding thereto, and as a result, have found the following facts.
上述したように、従来ではCr鉱石はスラグ中に溶解し
た後、スラグ中の炭材により還元されるものと考えられ
ているが、実際の還元反応のほとんどは、実は溶湯中の
Ｃが還元物質として作用していることが判明した。した
がつて、Cr鉱石のスラグ中への溶解ではなく、高温に加
熱されたCr鉱石への溶湯の接触が還元速度の律速であ
り、溶湯を鉱石に積極的に接触させることにより還元速
度を効果的に高めることができる。As described above, it is conventionally thought that the Cr ore is dissolved in the slag and then reduced by the carbonaceous material in the slag. Was found to be acting. Therefore, the contact of the molten metal with the ore heated to a high temperature is the rate-determining rate of reduction rather than the dissolution of the ore in the slag, and the reduction rate is effected by positively contacting the molten metal with the ore. Can be increased.
上述したように、従来では着熱効率向上に対する技術
的限界や耐火物の損耗の面で二次燃焼比を大きく上げら
れないというのが基本的な考え方であるが、二次燃焼を
主としてスラグ中で生じさせるようO2を吹き込み、且つ
スラグを強撹拌することにより、高二次燃焼を確保しつ
つ着熱効率を効果的に高めることができる。このような
高二次燃焼、高着熱効率により、スラグ及びスラグ中の
Cr鉱石の温度が高くなり、 Cr2O3＋Ｃ＝Cr＋CO で表わされるＣ（溶湯中Ｃ）によるCr鉱石の還元速度を
効果的に高めることができる。As described above, in the past, the basic idea was that the secondary combustion ratio could not be increased significantly in terms of the technical limit for improving the heating efficiency and the wear of refractories, but secondary combustion was mainly performed in slag. By blowing O 2 and generating strong agitation of the slag so as to generate the heat, it is possible to effectively increase the heating efficiency while ensuring high secondary combustion. Due to such high secondary combustion and high heating efficiency, slag and slag
The temperature of the Cr ore is increased, and the reduction rate of the Cr ore by C ( C in the molten metal) represented by Cr 2 O 3 + C = Cr + CO can be effectively increased.
従来法では、還元処理の一時期または全期間、O2の底
吹きを行つている例があるが、このようなO2底吹きは、
二次燃焼に有害である。すなわち、O2を底吹きすると溶
湯中で大量のCOガスを生じさせて溶湯を強撹拌し、この
結果、溶湯スプラツシユが二次燃焼域に達し、溶湯中Ｃ
がO2と反応することにより二次燃焼が阻害される。した
がつて還元期間の一部または全部を問わず、O2を底吹き
するのは絶対に避ける必要がある。In the conventional method, one time or lifetime reduction treatment, but the bottom of the O 2 blowing There are examples are Gyotsu, blow such O 2 bottom,
Harmful for secondary combustion. That is, when O 2 is blown from the bottom, a large amount of CO gas is generated in the molten metal and the molten metal is vigorously stirred. As a result, the molten metal splash reaches the secondary combustion zone, and
Reacts with O 2 to inhibit secondary combustion. Therefore, regardless of part or all of the reduction period, bottom-blowing of O 2 must be avoided.
本発明は、このような知見に基づき次のような条件を
規定し、これにより高い処理速度での還元処理を可能な
らしめたものである。The present invention defines the following conditions based on such knowledge, thereby enabling reduction processing at a high processing speed.
（イ）撹拌ガスの底吹きと横吹きの組み合せにより、溶
湯をスラグ中のCr鉱石の存在する領域に積極的に拡散さ
せ、溶湯中ＣによりCr鉱石の還元作用を促進させる。(A) The combination of bottom blowing and horizontal blowing of the stirring gas actively diffuses the molten metal into the region of the slag where the Cr ore is present, and promotes the reducing action of the Cr ore by C in the molten metal.
（ロ）所定レベル以上の二次燃焼比が得られるよう、脱
炭用O2とは別に二次燃焼用O2の吹き込みを行う。そし
て、この二次燃焼用O2を上吹きランスからスラグ中に吹
き込んで二次燃焼領域をスラグ中に形成させ、且つ横吹
きガスによりスラグを強撹拌し、二次燃焼により生じた
熱をCr鉱石に着熱させる。(B) The secondary combustion O 2 is blown separately from the decarburization O 2 so as to obtain a secondary combustion ratio higher than a predetermined level. Then, the secondary combustion O 2 is blown into the slag from the upper blowing lance to form a secondary combustion region in the slag, and the slag is vigorously stirred by the side-blown gas, and the heat generated by the secondary combustion is converted into Cr. Heat the ore.
（ハ）溶湯中Ｃによる還元作用及び上吹きO2による二次
燃焼が阻害されないようにするため、横吹きガス及び底
吹きガスはCOまたは不活性ガスとし、O2は使わない。(C) In order to prevent the reduction action by C in the molten metal and the secondary combustion by top-blown O 2 from being hindered, the side-blown gas and the bottom-blown gas are CO or an inert gas, and O 2 is not used.
すなわち、本発明は底吹き羽口、横吹き羽口及び上吹
きランスを備えた溶融還元炉を用い、Cr鉱石等のCr原料
を炭材のＣ源により還元して高Cr溶銑を得る方法におい
て、還元期間中、下記（イ）〜（ハ）のガス吹き込みを
行い、 （イ）底吹き羽口からCOまたは／および不溶性ガスを吹
き込む、 （ロ）ガス流の少なくとも一部が、底吹きガスによる溶
湯隆起部に当たるよう、横吹き羽口からCOまたは／およ
び不活性ガスを吹き込む、 （ハ）上吹きランスから、溶湯中へ脱炭用O2を吹き込む
とともに、スラグ中へ二次燃焼用O2を吹き込む、 且つ、二次燃焼比を0.3以上に保持しつつ還元処理を行
うことをその基本的特徴とする。That is, the present invention relates to a method of obtaining a high Cr hot metal by reducing a Cr raw material such as Cr ore with a C source of carbonaceous material using a smelting reduction furnace provided with a bottom blowing tuyere, a side blowing tuyere and an upper blowing lance. During the reduction period, the following gas blowing (a) to (c) is performed; (b) CO or / and an insoluble gas is blown from the bottom blowing tuyere; as striking the melt elevation according blown with CO and / or inert gas from the side blowing tuyeres, from (c) top-blow lance, into the melt with blowing decarburization for O 2, O for secondary combustion into the slag Its basic features are to blow 2 and to perform reduction treatment while maintaining the secondary combustion ratio at 0.3 or more.
以下、本発明の詳細を説明する。 Hereinafter, details of the present invention will be described.
第１図及び第２図は本発明法を模式的に示したもので
ある。1 and 2 schematically show the method of the present invention.
本発明では、主に転炉型の溶融還元炉を使用してCr鉱
石やCrペレツト等のCr原料の還元を行うもので、具体的
には、底吹き羽口（１）、横吹き羽口（２）及び上吹き
ランス（３）を備えた炉を用いる。In the present invention, reduction of Cr raw materials such as Cr ore and Cr pellets is mainly performed using a converter-type smelting reduction furnace. Specifically, a bottom-blowing tuyere (1) and a side-blowing tuyere A furnace equipped with (2) and a top lance (3) is used.
本発明法によれば、上記溶融還元炉中の金属浴にCr原
料（以下、Cr鉱石を例に説明する。）、炭材及びフラツ
クスが装入され、次のような条件で還元処理が行われ
る。According to the method of the present invention, a Cr raw material (hereinafter, described as an example of a Cr ore), a carbon material, and a flux are charged into a metal bath in the smelting reduction furnace, and a reduction treatment is performed under the following conditions. Will be
まず、還元処理中は、その初期から終期に至るまで底
吹き羽口（１）、横吹き羽口（２）及び上吹きランス
（３）からのガス吹き込みが行われる。First, during the reduction process, gas is blown from the bottom blowing tuyere (1), the side blowing tuyere (2) and the top blowing lance (3) from the beginning to the end.
底吹き羽口（１）及び横吹き羽口（２）からのガス吹
き込みは、両者の協働作用により溶湯をスラグ中に拡散
させ、還元速度を飛躍的に高める効果をもたらす。The gas blowing from the bottom-blow tuyere (1) and the side-blow tuyere (2) has the effect of diffusing the molten metal into the slag due to the cooperative action of the two, and dramatically increasing the reduction rate.
前述したように、本発明者はスラグ中のCr鉱石の還元
は、大部分溶湯中のＣを還元物質として進行するという
事実を解明し、これに基づき溶湯を強撹拌してスラグ
（Cr鉱石が浮遊する領域）中に積極的に拡散させて還元
速度を高めるようにするものである。このため本発明
は、底吹き羽口（１）から撹拌ガスを供給して溶湯面に
隆起部（Ａ）を形成し、同時に、横吹き羽口（２）から
ガス流の少なくとも一部が上記溶湯隆起部（Ａ）に当た
るようにして撹拌ガスを供給するものであり、この横吹
きガスにより溶湯隆起部（Ａ）の溶湯がスラグ中に飛散
することになる。スラグの見掛比重は通常0.3〜0.5であ
り、一方、Cr鉱石の嵩比重は3.0前後であり、したがつ
てスラグ中のCr鉱石は、第２図に示すようにほとんどス
ラグ下部領域に集中して浮遊している。上記のように溶
湯隆起部を横吹きガスで飛散させると、この飛散溶湯
は、第２図からも判るようにCr鉱石が存在するスラグ下
部領域に拡散し、この拡散溶湯中のＣがCr2O3を還元
し、高い還元速度が得られる。このような効果を得るた
めには、底吹き及び横吹きとも比較的大量のガスを吹き
込み、強撹拌を行う必要があることは言うまでもない
が、その吹き込みガス量は溶湯量、溶湯深さ等に応じて
決定される。第８図は底吹きガス量（底吹き羽口１本当
り・溶湯1Ton当りのNm3/min）と溶湯中のCr上昇速度と
の関係を概略的に示したもので、底吹きガス量の増加に
伴いCr上昇速度、すなわちCr還元速度が上昇し、効率的
な還元反応が生じていることが判る。As described above, the present inventors elucidated the fact that the reduction of Cr ore in slag mostly proceeds with C in the molten metal as a reducing substance, and based on this, the molten metal was vigorously agitated and slag (Cr ore was removed). (A floating region) to increase the reduction rate. Therefore, according to the present invention, the rising gas (A) is formed on the surface of the molten metal by supplying the stirring gas from the bottom blowing tuyere (1), and at the same time, at least a part of the gas flow from the horizontal blowing tuyere (2) The stirring gas is supplied so as to hit the molten metal protuberance (A), and the molten metal of the molten metal protruding part (A) is scattered into the slag by the side-blown gas. The apparent specific gravity of slag is usually 0.3 to 0.5, while the bulk specific gravity of Cr ore is around 3.0, so that the Cr ore in the slag is mostly concentrated in the lower area of the slag as shown in Fig. 2. Floating. When the raised portion of the molten metal is scattered by the side-blown gas as described above, the scattered molten metal diffuses into the lower region of the slag where the Cr ore is present as can be seen from FIG. 2, and C in the diffused molten metal becomes Cr 2 O 3 is reduced and a high reduction rate is obtained. In order to obtain such an effect, it is needless to say that a relatively large amount of gas must be blown in both the bottom blow and the side blow to perform strong stirring, but the amount of the blown gas depends on the amount of the molten metal, the depth of the molten metal, and the like. Determined accordingly. FIG. 8 schematically shows the relationship between the amount of bottom blown gas (Nm 3 / min per one blown tuyere and 1 Ton of molten metal) and the rate of rise of Cr in the molten metal. It can be seen that the Cr increase rate, that is, the Cr reduction rate increases with the increase, and an efficient reduction reaction occurs.
このような作用を得るためには、横吹きガス炉の上下
方向及び水平方向においてなるべく正確に上記溶湯隆起
部（Ａ）に当たるようにすることが好ましく、例えば、
水平方向においては第３図（ａ）及び（ｂ）に示すよう
な位置関係で底吹き羽口（１）及び横吹き羽口（２）を
設けることが好ましい。In order to obtain such an effect, it is preferable to hit the molten metal ridge (A) as accurately as possible in the vertical and horizontal directions of the horizontal blowing gas furnace.
In the horizontal direction, it is preferable to provide the bottom blown tuyere (1) and the horizontal blown tuyere (2) in a positional relationship as shown in FIGS. 3 (a) and 3 (b).
横吹きガスは、上述したような溶湯の拡散作用に加
え、二次燃焼領域が形成されるスラグの撹拌作用をも行
うものであり、これについては後述する。The side-blown gas performs a function of stirring the slag in which the secondary combustion region is formed, in addition to the function of diffusing the molten metal as described above, which will be described later.
本発明で使用される横吹きガス及び底吹きガスは、CO
及び不活性ガス（N2,Ar等）に限定され、O2は使用しな
い。これは次のような理由による。The side-blown gas and bottom-blown gas used in the present invention are CO
And inert gas (N 2 , Ar, etc.), and O 2 is not used. This is for the following reasons.
まず、横吹きガスにO2を用いると、Cr鉱石還元のため
に飛散させた溶湯中のＣとこのO2とが反応し、溶湯中Ｃ
による還元作用を阻害してしまうという基本的問題があ
る。加えてO2を使用した場合、耐火物の温度が上昇し、
耐火物の損耗という問題を生じる。First, when O 2 is used as the side-blown gas, C in the molten metal scattered for the reduction of Cr ore reacts with this O 2, and C 2
There is a basic problem that the reduction action by the oxidase is hindered. In addition, when O 2 is used, the temperature of the refractory rises,
The problem of wear of refractories occurs.
また、底吹きガスにO2を用いると、上述したように溶
湯中で大量のCOガスを生じさせて溶湯を強撹拌し過ぎ、
この結果、溶湯のスプリツシユが二次燃焼領域（第２図
参照）に達し、溶湯中Ｃが後述する二次燃焼用O2と反応
して二次燃焼が阻害されてしまう。加えて、O2を使用す
ると底吹き羽口など耐火物の温度が上がり過ぎるため冷
却ガス（C3H5等）を添加する必要があり、これも底吹き
ガス量を増大させ、強撹拌→溶湯スプラツシユの発生を
過大に助長することになる。第４図は、N2底吹きを行う
本発明法と、N2に代えO2底吹きを行つた比較例につい
て、設定二次燃焼比〔PcO2/（DcO2＋鉱石中O2）〕に対
する実際の二次燃焼比（実測）を調べた結果を示すもの
で、O2底吹きにより二次燃焼が阻害されることが示され
ている。Also, when O 2 is used as the bottom blown gas, a large amount of CO gas is generated in the molten metal as described above, and the molten metal is excessively stirred,
As a result, Supuritsushiyu of the molten metal reaches the secondary combustion region (see FIG. 2), the reaction to secondary combustion and the secondary combustion O 2 the molten metal in C will be described later is inhibited. In addition, if O 2 is used, the temperature of the refractory such as the bottom-blowing tuyere rises too high, so it is necessary to add a cooling gas (C 3 H 5 etc.). This will excessively promote the generation of molten metal splash. FIG. 4 shows a set secondary combustion ratio [PcO 2 / (DcO 2 + O 2 in ore)] for the method of the present invention in which N 2 bottom blowing is performed and a comparative example in which O 2 bottom blowing is performed instead of N 2. The figure shows the result of examining the actual secondary combustion ratio (actual measurement) with respect to, and shows that secondary combustion is inhibited by O 2 bottom blowing.
なお、撹拌ガスたるCOやN2,Ar等の不活性ガスは、単
独または混合して使用することができる。In addition, an inert gas such as CO, N 2 , or Ar serving as a stirring gas can be used alone or as a mixture.
次に、上吹きランス（３）からは溶湯中に脱炭用O2の
吹き込みが行われるとともに、スラグ中に二次燃焼用O2
の吹き込みが行われる。上吹きランス（３）は、脱炭用
O2のノズル孔と二次燃焼用O2のノズル孔とを備えてお
り、二次燃焼用O2は、その供給用ノズル孔から脱炭用O2
よりも外側の斜め下方に供給される。Next, O 2 for decarburization is blown into the molten metal from the upper blowing lance (3), and O 2 for secondary combustion is blown into the slag.
Is performed. Upper blowing lance (3) is for decarburization
O 2 in which a nozzle hole and a secondary combustion O 2 nozzle holes, the secondary combustion O 2 is, O 2 for decarburization from the supply nozzle holes
It is supplied diagonally below and outside.
本発明では、二次燃焼領域を主としてスラグ内に形成
させつつ高二次燃焼を実現させるものであり、このよう
に二次燃焼領域をスラグ内に形成し且つ横吹きガスによ
つてスラグを強撹拌することにより、高二次燃焼を確保
しつつ高い着熱効率を得ることができる。したがつて、
上記二次燃焼用O2は、主としてスラグ内に二次燃焼領域
が形成されるようスラグ中に吹き込まれることが必要で
ある。In the present invention, high secondary combustion is realized while forming the secondary combustion region mainly in the slag. Thus, the secondary combustion region is formed in the slag, and the slag is strongly stirred by the side-blown gas. By doing so, it is possible to obtain high heating efficiency while ensuring high secondary combustion. Therefore,
The secondary combustion O 2 needs to be mainly blown into the slag so that a secondary combustion region is formed in the slag.
具体的には、上吹きランスの高さがスラグや溶湯レベ
ルに対し適度なレベルに設定されることが必要である。
すなわち、上吹きランス（３）はそのノズル孔高さをス
ラグ面上方或いはスラグ面下とすることができるが、そ
の高さが高過ぎると二次燃焼領域がスラグ内に形成され
なくなり、着熱効率が低下するという問題があり、ま
た、ランス高さが低過ぎると二次燃焼領域が適正に形成
されなくなる。Specifically, it is necessary that the height of the upper blowing lance is set to an appropriate level with respect to the slag and the molten metal level.
That is, the nozzle hole height of the upper blowing lance (3) can be set above or below the slag surface. However, if the height is too high, the secondary combustion region is not formed in the slag, and the heating efficiency is reduced. In addition, if the height of the lance is too low, the secondary combustion region is not properly formed.
第５図はランス先端のスラグ面（フオーミングレベ
ル）からの高さと着熱効率との関係を示すもので、ラン
ス高さがスラグ面に対して高過ぎると良好な着熱効率が
得られなくなることが示されている。また、第６図は横
吹きガス量と着熱効率との関係を示すもので、横吹きガ
スを大量に吹き込みスラグ層を強撹拌することにより良
好な着熱効率が得られることが判る。FIG. 5 shows the relationship between the height of the lance tip from the slag surface (forming level) and the heat transfer efficiency. If the lance height is too high relative to the slag surface, good heat transfer efficiency may not be obtained. It is shown. FIG. 6 shows the relationship between the amount of laterally blown gas and the heat transfer efficiency. It can be seen that good heat transfer efficiency can be obtained by blowing a large amount of the horizontally blown gas and strongly stirring the slag layer.
上記二次燃焼比は、排ガス中のガス成分の（CO2＋H
2O）／（CO＋CO2＋H2＋H2O）で定義されるが、本発明で
はこの二次燃焼比を0.3以上として上述の還元処理を行
う。本発明では、高着熱効率が得られるため、二次燃焼
比を上記のように高くすることにより、高い還元処理性
（還元速度）が得られるが、これに加え、二次燃焼比を
上げることにより炭材（主としてコークス）の添加量を
低く抑えることができ、この結果、炭材原単位の低減を
図ることができるとともに、溶湯中のＰ成分のほとんど
が炭材により持ち込まれることから、溶湯中Ｐの低減を
図ることができる。また二次燃焼比が高くなると、気化
脱硫現象が活発になり、溶湯中のＳも低下する。このよ
うな観点からも本発明では二次燃焼比を0.3以上とす
る。第７図は、本発明方式の溶融還元における炉内二次
燃焼比とコークス原単位、溶湯中Ｐ成分及びＳ成分との
関係を示すもので、二次燃焼比を0.3以上とすることに
より、コークス原単位が抑えられ、且つ溶湯中のP,Sも
適切に低減している。The above secondary combustion ratio is determined based on the gas component in the exhaust gas (CO 2 + H
2 O) is defined by / (CO + CO 2 + H 2 + H 2 O) , but in the present invention perform the reduction process described above the secondary combustion ratio as 0.3 or more. In the present invention, since a high heat transfer efficiency is obtained, a high reduction treatment property (reduction rate) can be obtained by increasing the secondary combustion ratio as described above. As a result, the amount of carbon material (mainly coke) added can be kept low. As a result, the carbon unit consumption can be reduced, and most of the P component in the molten metal is carried by the carbon material. Medium P can be reduced. Also, when the secondary combustion ratio increases, the vaporization desulfurization phenomenon becomes active, and S in the molten metal also decreases. From such a viewpoint, the present invention sets the secondary combustion ratio to 0.3 or more. FIG. 7 shows the relationship between the in-furnace secondary combustion ratio and the coke basic unit, the P component and the S component in the molten metal in the smelting reduction of the method of the present invention. By setting the secondary combustion ratio to 0.3 or more, The basic unit of coke is suppressed, and P and S in the molten metal are appropriately reduced.
以上が本発明の詳細な内容であるが、本発明を実際に
実施する場合、通常、装入−造滓・昇熱−Cr鉱石溶融還
元という工程となる。The above is the detailed contents of the present invention. When the present invention is actually carried out, usually, the steps are charging, slag making, heat-up, and smelting reduction of Cr ore.
ここで装入工程とは溶銑等のFe源を装入し、炉内に金
属浴を形成することを意味する。造滓・昇熱工程では浴
中への送酸と炭材、フラツクス等の装入を行い、Cr鉱石
の還元領域となるスラグを形成するとともに、浴温度を
還元に必要な温度まで高める。Cr鉱石溶融還元工程で
は、溶融還元炉中にCr鉱石、炭材、フラツクスが順次投
入される。この工程末期においてはCr鉱石の投入を行う
ことなく仕上還元がなされ、溶湯中のCr濃度が目標値と
なつた時点で還元処理を完了させる。Here, the charging step means charging a Fe source such as hot metal and forming a metal bath in the furnace. In the slag making and heating process, acid is fed into the bath and carbon materials, flux, etc. are charged to form slag that serves as a reduction region for Cr ore, and the bath temperature is raised to the temperature required for reduction. In the Cr ore smelting reduction process, Cr ore, carbonaceous material, and flux are sequentially charged into the smelting reduction furnace. In the final stage of the process, finish reduction is performed without charging the Cr ore, and the reduction process is completed when the Cr concentration in the molten metal reaches the target value.
なお、本発明では、Cr原料、炭材等の原料は、炉口上
方から落下させる所謂上置きにより装入することができ
る。In the present invention, the raw materials such as the Cr raw material and the carbonaceous material can be charged by dropping the furnace raw material from above the furnace opening.
転炉型溶融還元炉（5Ton）を用い、3.7Tonの溶銑を装
入した後、Cr鉱石、コークス及びフラツクスを装入して
溶融還元を行い、5.5Tonの18％Cr溶銑を得た。第９図
は、その際の溶銑中のCr,C濃度、浴温度、二次燃焼比OD
等の変化、及びランスによる送酸量、原料装入量を示し
たものである。Using a converter type smelting reduction furnace (5Ton), after charging 3.7Ton hot metal, Cr ore, coke and flux were charged and smelting reduction was performed to obtain 5.5Ton 18% Cr hot metal. Fig. 9 shows the Cr and C concentrations in the hot metal, bath temperature, and secondary combustion ratio OD
And the like, the amount of acid supplied by a lance, and the amount of raw materials charged.
第10図は本実施例の処理時間（還元開始から終了まで
の時間）を、第11図（ａ）及び（ｂ）に示す従来方式に
よる処理時間と比較して示したものである。なお、従来
法（１）は上吹きランスから微粉炭及びO2を上吹きし、
底吹き羽口から撹拌ガスを吹き込む方法、従来法（２）
は上吹きランスからスラグ上にO2を吹き込むとともに、
底吹き羽口からN2、横吹き羽口からN2,O2をそれぞれ引
き込む方法であり、具体的な操業条件は以下の通りであ
る。FIG. 10 shows the processing time (time from the start to the end of reduction) of this embodiment in comparison with the processing time of the conventional method shown in FIGS. 11 (a) and 11 (b). In the conventional method (1), pulverized coal and O 2 are blown up from the top blow lance,
A method of blowing stirring gas from the bottom tuyere, conventional method (2)
Blows O 2 from the top blowing lance onto the slag,
N 2 from the bottom tuyeres, a method to pull N 2 from the side tuyeres, O 2, respectively, specific operating conditions are as follows.
従来法（１） 上吹きO2 1700Nm3/Hr（仕上還元期） 底吹きN2 350Nm3/Hr（仕上還元期） 溶 銑 10Ton Cr鉱 4600kg（ランスよりインジエクシヨ ン） 炭 材 6700kg（ランスよりインジエクシヨ ン） 従来法（２） 上吹きO2 1000Nm3/Hr（仕上還元期） 底吹きN2 120Nm3/Hr（仕上還元期） 横吹きN2 350Nm3/Hr（仕上還元期） 溶 銑 5Ton Cr鉱（粉鉱石） 5000kg（上置き） 炭 材 3200Kg（上置き） 第10図によれば、従来法（２）はCr濃度が６〜７％程
度にしかならず、また従来法（１）ではCr濃度は目標の
18％にはなるものの、処理に120分も要している。これ
に対し、本発明によれば約半分の60分の処理時間で18％
Crに達しており、本発明の極めて優れた処理性能が示さ
れている。Conventional method (1) the top-blown O 2 1700Nm 3 / Hr (finishing reduction period) bottom blowing N 2 350Nm 3 / Hr (finish-reduction phase) molten iron 10ton Cr ore 4600Kg (Injiekushiyo emissions from lance) carbonaceous material 6700Kg (Injiekushiyo from Reims emissions) conventional method (2) top-blown O 2 1000 Nm 3 / Hr (finishing reduction period) bottom blowing N 2 120 Nm 3 / Hr (finishing reduction period) horizontal blowing N 2 350 Nm 3 / Hr (finish-reduction phase) molten iron 5 ton Cr Ore (fine ore) 5000 kg (top) Charcoal 3200 kg (top) According to Fig. 10, the conventional method (2) has a Cr concentration of only about 6 to 7%, and the conventional method (1) has a Cr concentration of only about 6 to 7%. Is the goal
Although it is 18%, it takes 120 minutes to process. On the other hand, according to the present invention, about half of the processing time of 60 minutes is 18%.
Cr, which indicates the extremely excellent processing performance of the present invention.
なお、第12図は本発明におけるCr純分投入速度（純Cr
量に換算したCr鉱石の投入速度）に対するCr上昇速度を
調べたもので、従来法（１）、（２）に較べ高いCr上昇
速度が得られていることが判る。FIG. 12 is a graph showing the rate of input of pure Cr (pure Cr) in the present invention.
It was found that the rate of increase in Cr with respect to the rate of input of Cr ore in terms of the amount was examined, and that a higher rate of increase in Cr was obtained as compared with the conventional methods (1) and (2).
以上述べた本発明によれば、溶湯によるCr鉱石の還元
作用を積極的に促進し、しかも高い二次燃焼比と着熱効
率を確保した処理を行うためCr鉱石の還元速度を従来レ
ベルに較べ大幅に上昇させることができ、このため溶融
還元処理を短時間で効率的に行うことができる。また、
二次燃焼比が高いため炭材原単位を下げることができる
とともに、得られる溶銑中のP,S成分量を低く抑えるこ
とができる効果がある。According to the present invention described above, the reduction action of Cr ore by the molten metal is positively promoted, and the reduction rate of Cr ore is significantly increased as compared with the conventional level in order to perform the treatment while ensuring a high secondary combustion ratio and heat transfer efficiency. And the smelting reduction treatment can be performed efficiently in a short time. Also,
Since the secondary combustion ratio is high, the carbon unit consumption can be reduced, and the P and S component amounts in the obtained hot metal can be reduced.
第１図及び第２図は本発明における溶融還元の原理を模
式的に示す説明図である。第３図（ａ）及び（ｂ）は底
吹き羽口に対する好ましい横吹きガス噴射方向を示す説
明図である。第４図は本発明法とO2底吹きを行う比較法
について、設定二次燃焼比に対する実測二次燃焼比を示
すものである。第５図は上吹きランス高さと着熱効率と
の関係を示すものである。第６図は横吹きガス量と着熱
効率との関係を示すものである。第７図は炉内二次燃焼
比と溶湯中のＳ量、Ｐ量及びコークス原単位との関係を
示すものである。第８図は本発明における底吹きガス量
に対するCr上昇速度の関係を概略的に示すものである。
第９図は実施例における溶湯中Cr,C濃度、浴温度、二次
燃焼比、ランス送酸量、原料供給量等の経時変化を示す
ものである。第10図は本発明実施例の還元処理時間を従
来法と比較して示すものである。第11図（ａ）及び
（ｂ）は第10図において示した従来法（１）、（２）の
処理方法を示す説明図である。第12図は本発明例におけ
るCr純分投入速度とCr上昇速度との関係を、従来法と比
較して示したものである。 図において、（１）は底吹き羽口、（２）は横吹き羽
口、（３）は上吹きランス、（Ａ）は溶湯隆起部であ
る。1 and 2 are explanatory diagrams schematically showing the principle of smelting reduction in the present invention. FIGS. 3 (a) and 3 (b) are explanatory views showing a preferred side-blown gas injection direction for the bottom-blow tuyere. FIG. 4 shows the measured secondary combustion ratio with respect to the set secondary combustion ratio for the method of the present invention and the comparative method of performing O 2 bottom blowing. FIG. 5 shows the relationship between the height of the upper blowing lance and the heat transfer efficiency. FIG. 6 shows the relationship between the amount of laterally blown gas and the heat transfer efficiency. FIG. 7 shows the relationship between the in-furnace secondary combustion ratio and the amounts of S and P in the molten metal and the basic unit of coke. FIG. 8 schematically shows the relationship between the amount of bottom blown gas and the rate of rise of Cr in the present invention.
FIG. 9 shows changes with time of the Cr and C concentrations in the molten metal, the bath temperature, the secondary combustion ratio, the lance acid supply amount, the raw material supply amount, and the like in the example. FIG. 10 shows the reduction processing time of the embodiment of the present invention in comparison with the conventional method. FIGS. 11 (a) and (b) are explanatory diagrams showing the processing methods of the conventional methods (1) and (2) shown in FIG. FIG. 12 shows the relationship between the Cr pure component feed rate and the Cr rise rate in the example of the present invention in comparison with the conventional method. In the figure, (1) is a tuyere with a bottom blow, (2) is a tuyere with a side blow, (3) is a lance with a top blow, and (A) is a bulge of molten metal.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 岩崎 克博 東京都千代田区丸の内１丁目１番２号 日本鋼管株式会社内 (72)発明者 井上 茂 東京都千代田区丸の内１丁目１番２号 日本鋼管株式会社内 (56)参考文献 特開 昭61−67727（ＪＰ，Ａ) 特開 昭61−279608（ＪＰ，Ａ) ────────────────────────────────────────────────── ─── Continuing on the front page (72) Katsuhiro Iwasaki, Inventor Katsuhiro Iwasaki, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Shigeru Inoue 1-1-2, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan (56) References JP-A-61-67727 (JP, A) JP-A-61-279608 (JP, A)
Claims (2)
を備えた溶融還元炉を用い、Cr鉱石等のCr原料を炭材の
Ｃ源により還元して高Cr溶銑を得る方法において、還元
期間中、下記（イ）〜（ハ）のガス吹き込みを行い、 （イ）底吹き羽口からCOまたは／および不溶性ガスを吹
き込む、 （ロ）ガス流の少なくとも一部が、底吹きガスによる溶
湯隆起部に当たるよう、横吹き羽口からCOまたは／およ
び不活性ガスを吹き込む、 （ハ）上吹きランスから、溶湯中へ脱炭用O2を吹き込む
とともに、スラグ中へ二次燃焼用O2を吹き込む、 且つ、二次燃焼比を0.3以上に保持しつつ還元処理を行
うことを特徴とするCr原料の溶融還元法。1. A method for obtaining high Cr hot metal by reducing a Cr raw material such as Cr ore by a C source of carbonaceous material using a smelting reduction furnace having a bottom blown tuyere, a side blown tuyere and a top blown lance. During the reduction period, the following gas blowing (a) to (c) is performed; (b) CO or / and an insoluble gas is blown from the bottom blowing tuyere; as striking the melt elevation according blown with CO and / or inert gas from the side blowing tuyeres, from (c) top-blow lance, into the melt with blowing decarburization for O 2, O for secondary combustion into the slag 2. A smelting reduction method for a Cr raw material, characterized in that a reduction treatment is performed while blowing 2 and maintaining the secondary combustion ratio at 0.3 or more.
面下に位置したランスにより、脱炭用O2及び二次燃焼用
O2を吹き込むことを特徴とする特許請求の範囲（１）記
載のCr原料の溶融還元法。2. A lance whose tip is located near or below the slag surface during operation, for decarburizing O 2 and secondary combustion.
The smelting reduction method of a Cr raw material according to claim 1, wherein O 2 is blown.
Priority Applications (10)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62201002A JP2595549B2 (en) | 1987-08-13 | 1987-08-13 | Melt reduction method of Cr raw material |
| AU22560/88A AU606457C (en) | 1987-08-13 | 1988-08-11 | Process for melt reduction of Cr starting material and melt reduction furnace |
| US07/360,916 US4961784A (en) | 1987-08-13 | 1988-08-11 | Method of smelting reduction of chromium raw materials and a smelting reduction furnace thereof |
| BR888807168A BR8807168A (en) | 1987-08-13 | 1988-08-11 | REDUCING FUSION PROCESS OF CHROME RAW MATERIALS AND ITS REDUCING FUSION OVEN |
| AT88906890T ATE107710T1 (en) | 1987-08-13 | 1988-08-11 | FURNACE AND PROCESS FOR REDUCING A CHROMIUM PRECURSOR BY MELTING. |
| EP88906890A EP0328677B1 (en) | 1987-08-13 | 1988-08-11 | PROCESS FOR MELT REDUCTION OF Cr STARTING MATERIAL AND MELT REDUCTION FURNACE |
| DE3850381T DE3850381T2 (en) | 1987-08-13 | 1988-08-11 | OVEN AND METHOD FOR REDUCING A CHROME PRE-PRODUCT BY MELTING. |
| PCT/JP1988/000800 WO1989001532A1 (en) | 1987-08-13 | 1988-08-11 | Process for melt reduction of cr starting material and melt reduction furnace |
| CA000596453A CA1338731C (en) | 1987-08-13 | 1989-04-12 | Method of smelting reduction of chromium raw materials and a smelting reduction furnace thereof |
| CN89103058A CN1047109A (en) | 1987-08-13 | 1989-05-06 | Melting and reducing method of chromium raw material and melting and reducing furnace |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62201002A JP2595549B2 (en) | 1987-08-13 | 1987-08-13 | Melt reduction method of Cr raw material |
| CA000596453A CA1338731C (en) | 1987-08-13 | 1989-04-12 | Method of smelting reduction of chromium raw materials and a smelting reduction furnace thereof |
| CN89103058A CN1047109A (en) | 1987-08-13 | 1989-05-06 | Melting and reducing method of chromium raw material and melting and reducing furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6447832A JPS6447832A (en) | 1989-02-22 |
| JP2595549B2 true JP2595549B2 (en) | 1997-04-02 |
Family
ID=27168269
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62201002A Expired - Lifetime JP2595549B2 (en) | 1987-08-13 | 1987-08-13 | Melt reduction method of Cr raw material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2595549B2 (en) |
-
1987
- 1987-08-13 JP JP62201002A patent/JP2595549B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6447832A (en) | 1989-02-22 |
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