JPH0413404B2 - - Google Patents
Info
- Publication number
- JPH0413404B2 JPH0413404B2 JP20565784A JP20565784A JPH0413404B2 JP H0413404 B2 JPH0413404 B2 JP H0413404B2 JP 20565784 A JP20565784 A JP 20565784A JP 20565784 A JP20565784 A JP 20565784A JP H0413404 B2 JPH0413404 B2 JP H0413404B2
- Authority
- JP
- Japan
- Prior art keywords
- molten iron
- secondary combustion
- oxygen
- gas
- converter
- 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
Links
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 76
- 229910052742 iron Inorganic materials 0.000 claims description 38
- 238000002485 combustion reaction Methods 0.000 claims description 31
- 239000007789 gas Substances 0.000 claims description 24
- 238000007664 blowing Methods 0.000 claims description 22
- 229910052799 carbon Inorganic materials 0.000 claims description 22
- 239000002893 slag Substances 0.000 claims description 16
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 15
- 238000007670 refining Methods 0.000 claims description 15
- 238000006243 chemical reaction Methods 0.000 claims description 12
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 7
- 229910001882 dioxygen Inorganic materials 0.000 claims description 7
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- 238000007254 oxidation reaction Methods 0.000 claims description 6
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 3
- 238000009841 combustion method Methods 0.000 claims description 3
- 230000003647 oxidation Effects 0.000 claims description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 2
- 239000001569 carbon dioxide Substances 0.000 claims description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 2
- 238000012546 transfer Methods 0.000 claims description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 33
- 229910052760 oxygen Inorganic materials 0.000 description 33
- 239000001301 oxygen Substances 0.000 description 33
- 229910052751 metal Inorganic materials 0.000 description 15
- 239000002184 metal Substances 0.000 description 15
- 238000005261 decarburization Methods 0.000 description 14
- 239000011651 chromium Substances 0.000 description 8
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 6
- 229910052804 chromium Inorganic materials 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- 238000003723 Smelting Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 239000000571 coke Substances 0.000 description 3
- 239000011449 brick Substances 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 229910017082 Fe-Si Inorganic materials 0.000 description 1
- 229910017133 Fe—Si Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 239000000112 cooling gas Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/35—Blowing from above and through the bath
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Description
（産業上の利用分野）
溶銑の脱炭の如き溶鉄精錬の改善に関してこの
明細書で述べる技術内容は、害精錬に随伴して発
生し又は発生させたCOガスを、精錬容器内で
CO2にまで酸化させ、それにより発生する酸化反
応熱を効率的に溶鉄に伝えることについての開発
研究の成果、とり分け溶銑の脱炭精錬時における
熱補償の向上に関するものであり、より具体的に
いうと転炉内での脱炭精錬時に発生するCOガス
をCO2まで酸化燃焼させてその反応熱を溶鉄に効
率よく伝えようとするものである。
最近の製鋼技術の発展は、従来転炉内で除去し
ていた燐を転炉装入前に除去する溶銑脱燐技術の
工程化において顕著である。
しかしこの溶銑脱燐に伴う大幅な温度降下のた
めに、通常の転炉操業では目標とする吹錬終了温
度が得られない場合があり、やむなくFe−Si合
金や炭素源を転炉内に添加して、Si又はＣの酸化
発熱により目標温度を得る操作が必要となる。
一方においてMn鉱石やCr鉱石などを転炉内に
添加し、該鉱石の還元によつて合金成分のMnや
Crを回収する方法の利用も進められつつあるが
この場合には、鉱石の顕熱と還元吸熱とを補うた
め、転炉に多量の炭素源たとえばコークスを添加
し、その酸化反応熱により不足熱を補う必要があ
る。
さらには、鉄源価格の変動に従い、溶銑よりス
クラツプ（鋼屑）が安価な場合には、転炉へのス
クラツプ投入量を増加するいわゆる低溶銑比操業
による経済的吹錬が所期されるがこの場合にもス
クラツプの溶解熱を補償するため、同じく多量の
炭素源による熱補償対策が必要とされる。
以上のように炭素源などを転炉内に添加する場
合も含め、上記の如き各種の精錬における熱補償
をより有利に成就するところに、この発明の有用
性は、以下逐次にのべるとおり明らかである。
（従来の技術）
特公昭59−2136号公報では、とくに含クロム鋼
の脱炭精錬に際し、溶鉄浴面にて発生するCOガ
スの燃焼を図るため酸素ガスを該浴面上に吹つけ
ることが開示されている。しかるにこの場合燃焼
反応生成物であるCO2ガスが、鋼中Ｃと反応して
再びCOガスになり、この反応は吸熱を伴うので、
溶鉄加熱の熱源として利用度が減殺される不利が
あつた。
（発明が解決しようとする問題点）
溶鉄の脱炭精錬に際し溶鉄浴面で生成するCO
ガスの該溶鉄に対する加熱源としての利用度をさ
らに高める方途を招くことがこの発明の目的であ
る。
（問題を解決するための手段）
この発明の目的は次の事項で有利に充足され
る。
溶鉄中の炭素ないしは別に添加した炭素源が精
錬容器の内部で酸化して発生する一酸化炭素ガス
を、精錬容器内で更に二酸化炭素ガスになるまで
酸化し、その反応熱を溶鉄に伝えるいわゆる２次
燃焼法による溶鉄の加熱に際し、
２次燃焼反応用の酸素ガスを、その気流の吹出
し方向が溶鉄浴と接触しない向きとしてスラグ中
に供給することを特徴とする、２次燃焼による溶
鉄の加熱方法。
さて精錬容器中に炭素源を加える場合も含め
て、該容器中における酸化反応熱の利用は、次式
(1)によつてあらわされる。Ｃ
＋１／２O2＝CO＋32740（Cal／mol） ……(1)
ここでＣは溶鉄中の炭素および添加した炭素
源。
溶鉄中炭素濃度（以下〔％Ｃ〕）が高い場合に
は、(1)式の反応が大部分であるが、低〔％Ｃ〕の
場合や、上吹き酸素ガスの流量やランス高さを調
整することにより次式の反応の発熱も得ることが
できる。
CO＋１／２O2＝CO2＋61750（Cal／mol） ……(2)
前述の熱補償の目的のためには高〔％Ｃ〕の場
合でも(2)式の反応を進めて大量の発熱を得ること
が望ましいが、通常の転炉操業では、発生する
COガスのうち高々20％を燃焼させるにとどまつ
ていた。
この発明では、従来技術の欠点であつたCOガ
スのCO2への燃焼効率の低さを大幅に改善するた
め、とくにスラグ中への酸素供給用羽口の浸漬配
置により、酸素気流が溶鉄に接しないようにその
噴出方向を溶鉄浴面と事実上平行にする。
第１図に従い具体的に説明を加えると図中１は
転炉炉体、２は底吹き羽口、３は溶鉄、４はスラ
グ、そして５は２次燃焼酸素供給用羽口であり、
６は脱炭用の酸素を供給するランスである。
ここにスラグ４中へ浸漬されている２次燃焼酸
素供給用羽口５は、溶銑装入時や溶鋼出鋼時に炉
体を傾動しても鉄浴面下に浸漬しない位置にて、
２本１組で対向する炉壁に設置し、酸素気流の中
心軸が転炉炉体１の空間で衝突するように方向を
決定する。
この設置要領を採用しないと、スラグ４の形成
が未だ不十分で２次燃焼酸素供給用羽口５がスラ
グ中に浸漬されないとき、酸素気流が対向する炉
壁に直接衝突して、炉壁耐火物を著しく溶損す
る。
一方、２次燃焼酸素供給用羽口５の設置高さ
は、転炉が直立状態でかつ脱炭吹錬の進行中、脱
炭用の酸素ランス６の下端より下方でしかも鉄溶
表面より上方になければならないが、転炉本体１
の形状や耐火物レンガの内容積、ランス高さ下限
などによつても変化するので、一般的には決めら
れず、各転炉毎に決定するを要する。
２次燃焼酸素供給用羽口５は、いわゆる２重管
羽口とし、その内管７より酸素又は酸素含有ガス
を、内管７と外管８との間のすき間から、羽口保
護用の冷却ガスを、それぞれ噴出するようにする
ことがのぞましい。
第２図に脱炭精錬挙動を模式的に示すように、
COガスによつてフオーミング（泡立ち）したス
ラグに対して、鋼浴と接触しないように２次燃焼
用酸素供給用羽口５からスラグ４中に酸素を吹込
むと、溶鉄３の溶面で発生したCOはCO2まで酸
化され、その反応熱はスラグに蓄えられる。
この蓄熱分は、底吹き羽口２を通して供給した
精錬用ガスによるスラグ／メタルの強撹拌の下に
溶鉄３側へ伝えられる。
すなわち、大量の熱がスラグ４を媒介として溶
鉄３へ移行するので、発生したCO2が次式(3)
CO2＋Ｃ＝2CO ……(3)
に従つて再びCOになるような吸熱反応を生ぜず、
効率よく溶鉄加熱に活用できる。
この発明の効果を十分に得るため、底吹き羽口
２を通して、溶鉄浴中に吹き込む精錬用ガスによ
る強撹拌を加えることがのぞましくここに底吹き
ガス流量は、スラグ４中の（％FeO）を低減する
効果の著しいとされている0.1Nm3／min・ｔ以上
がとくに好ましい。
第３図には底吹きガス流量とスラグ／メタル間
の温度差との関係を示し、底吹きガス流量が
0.1Nm3／min・ｔ以上の場合にスラグ／メタル間
の温度差は著しく小さく、スラグ／メタル間の混
合が十分になされて、伝熱が効率よく行われてい
ることを示す。
これに対し第４図ａ，ｂに示した上掲特公昭59
−21367号公報に開示のような従来の技術では、
脱炭精錬の反応生成物であるCOガスの二次燃焼
酸素として、上吹きランス９又は、炉口近くの炉
壁に設けた吹込み口１０から酸素又は酸素含有ガ
スを溶鉄浴３に向つて下向きに吹付けているの
で、さきに式(3)にて示した吸熱反応を生じて、事
実上、式(1)による反応熱、しか利用され得なかつ
たのである。
上記のようにして、この発明の実施が、底吹き
転炉又は、上底吹き転炉において有利に適合する
のは明らかである。
（実施例）
実施例 １
第１図に示した炉容５トンの上底吹き転炉を用
い、２次燃焼酸素供給用羽口５はとくにトラニオ
ン軸近傍にて転炉炉体１の直径上で向い合う２本
１組のみを設置した。
酸素ガスは炉底羽口２から5Nm3／min、上吹
きランス６から10Nm3／minとし、そして２次燃
焼酸素供給用羽口５からは２本の合計で5Nm3／
minをそれぞれ供給した。
約５トンの溶銑を表１に示す条件にて転炉内に
装入した後に上述の酸素ガスで吹錬を続けて、炭
素濃度〔％Ｃ〕が約0.10％になつた時点での溶鋼
温度を測定しこの間また、〔％Ｃ〕が約１％の時
点で出鋼孔から炉内のガス採取を行い、ガスクロ
マトグラフイーによりガス組成の分析も行つて、
表１に示す精錬成績を得た。
(Industrial Application Field) The technical content described in this specification regarding the improvement of molten iron refining such as decarburization of hot metal is to remove CO gas generated or produced along with harmful smelting in the smelting vessel.
The results of development research on oxidizing CO 2 and efficiently transmitting the resulting oxidation reaction heat to molten iron, and in particular on improving heat compensation during decarburization and refining of hot metal. In other words, the CO gas generated during decarburization refining in the converter is oxidized and burned to CO2 , and the heat of reaction is efficiently transferred to the molten iron. Recent developments in steelmaking technology are notable in the process of hot metal dephosphorization technology that removes phosphorus, which was conventionally removed in the converter, before charging into the converter. However, due to the significant temperature drop associated with this hot metal dephosphorization, the target blowing completion temperature may not be achieved during normal converter operation, so Fe-Si alloys and carbon sources are unavoidably added to the converter. Therefore, it is necessary to perform an operation to obtain the target temperature using heat generated by oxidation of Si or C. On the other hand, Mn ore, Cr ore, etc. are added to the converter, and by reducing the ore, the alloying component Mn and
The use of a method to recover Cr is also progressing, but in this case, in order to compensate for the sensible heat and reduction endotherm of the ore, a large amount of carbon source, such as coke, is added to the converter, and the heat of the oxidation reaction replaces the insufficient heat. need to be supplemented. Furthermore, due to fluctuations in iron source prices, if scrap is cheaper than hot metal, economical blowing is expected by increasing the amount of scrap input to the converter, so-called low hot metal ratio operation. In this case as well, heat compensation measures using a large amount of carbon source are required in order to compensate for the heat of dissolution of the scrap. The usefulness of the present invention is clear as described below in that it more advantageously achieves heat compensation in various types of refining as described above, including when carbon sources are added into the converter. be. (Prior art) Japanese Patent Publication No. 59-2136 discloses that, especially during decarburization of chromium-containing steel, it is possible to blow oxygen gas onto the surface of a molten iron bath in order to burn the CO gas generated on the surface of the bath. Disclosed. However, in this case, CO 2 gas, which is a combustion reaction product, reacts with C in the steel and becomes CO gas again, and this reaction is accompanied by endothermy.
It had the disadvantage of being less useful as a heat source for heating molten iron. (Problem to be solved by the invention) CO generated on the surface of the molten iron bath during decarburization and refining of molten iron.
It is an object of this invention to provide a way to further increase the utility of gas as a heating source for the molten iron. (Means for solving the problem) The objects of the present invention are advantageously fulfilled by the following matters. The carbon monoxide gas generated by the oxidation of carbon in the molten iron or a separately added carbon source inside the smelting vessel is further oxidized into carbon dioxide gas within the smelting vessel, and the heat of reaction is transferred to the molten iron. Heating of molten iron by secondary combustion, characterized in that when heating molten iron by secondary combustion method, oxygen gas for secondary combustion reaction is supplied into the slag with the blowing direction of the airflow not coming into contact with the molten iron bath. Method. Now, the utilization of the heat of oxidation reaction in the refining vessel, including the case where a carbon source is added to the vessel, is as follows:
It is expressed by (1). C + 1/2O 2 = CO + 32740 (Cal/mol) ... (1) Here, C is carbon in the molten iron and the added carbon source. When the carbon concentration in the molten iron (hereinafter referred to as [%C]) is high, the reaction expressed by equation (1) takes place in most cases, but when the carbon concentration in the molten iron is low [%C], the flow rate of top-blown oxygen gas and the lance height may be changed. By adjusting, the exothermic reaction of the following formula can also be obtained. CO + 1/2O 2 = CO 2 + 61750 (Cal/mol) ...(2) For the purpose of heat compensation mentioned above, even in the case of high [%C], the reaction of equation (2) is carried out to generate a large amount of heat. However, during normal converter operation,
At most, only 20% of the CO gas was burned. In this invention, in order to significantly improve the low combustion efficiency of CO gas to CO 2 , which was a drawback of the conventional technology, the oxygen gas flow is applied to the molten iron by immersing the tuyeres for supplying oxygen into the slag. The direction of the jet is made practically parallel to the surface of the molten iron bath so that it does not come in contact with the surface of the molten iron bath. To explain in detail according to FIG. 1, in the figure, 1 is a converter furnace body, 2 is a bottom blowing tuyere, 3 is molten iron, 4 is slag, and 5 is a tuyere for supplying secondary combustion oxygen.
6 is a lance that supplies oxygen for decarburization. The secondary combustion oxygen supply tuyere 5 immersed in the slag 4 is located at a position where it will not be immersed below the surface of the iron bath even if the furnace body is tilted during charging of hot metal or tapping of molten steel.
They are installed in sets of two on opposing furnace walls, and their directions are determined so that the central axes of the oxygen streams collide in the space of the converter body 1. If this installation procedure is not adopted, when the slag 4 is not sufficiently formed and the secondary combustion oxygen supply tuyere 5 is not immersed in the slag, the oxygen stream will directly collide with the opposing furnace wall, causing the furnace wall to become refractory. Causes significant damage to materials. On the other hand, the installation height of the tuyere 5 for supplying secondary combustion oxygen is set below the lower end of the oxygen lance 6 for decarburization and above the surface of the molten iron when the converter is in an upright state and decarburization blowing is in progress. However, the converter body 1
Since it varies depending on the shape of the refractory brick, the internal volume of the refractory brick, the lower limit of the lance height, etc., it cannot be determined in general and must be determined for each converter. The secondary combustion oxygen supply tuyere 5 is a so-called double-tube tuyere, and oxygen or oxygen-containing gas is supplied from the inner tube 7 through the gap between the inner tube 7 and the outer tube 8 to protect the tuyere. It is desirable that the cooling gas be spouted separately. As shown in Fig. 2, which schematically shows the decarburization refining behavior,
Oxygen is blown into the slag 4 from the secondary combustion oxygen supply tuyeres 5 to prevent it from coming into contact with the steel bath. The CO produced is oxidized to CO 2 , and the heat of the reaction is stored in the slag. This stored heat is transferred to the molten iron 3 side while the slag/metal is strongly stirred by the refining gas supplied through the bottom blowing tuyeres 2. That is, since a large amount of heat is transferred to the molten iron 3 through the slag 4, an endothermic reaction occurs in which the generated CO 2 becomes CO again according to the following equation (3) CO 2 + C = 2CO ... (3) does not produce
It can be used efficiently to heat molten iron. In order to fully obtain the effects of this invention, it is desirable to add strong stirring by the refining gas blown into the molten iron bath through the bottom blowing tuyere 2. A value of 0.1 Nm 3 /min·t or more, which is said to have a remarkable effect of reducing FeO), is particularly preferable. Figure 3 shows the relationship between the bottom blowing gas flow rate and the temperature difference between the slag and metal.
At 0.1 Nm 3 /min·t or more, the temperature difference between the slag and metal is extremely small, indicating that the slag and metal are sufficiently mixed and heat transfer is performed efficiently. In contrast, the above-mentioned special public service shown in Figure 4 a and b
In the conventional technology as disclosed in the −21367 publication,
As secondary combustion oxygen of CO gas, which is a reaction product of decarburization refining, oxygen or oxygen-containing gas is directed toward the molten iron bath 3 from the top blowing lance 9 or the blowing port 10 provided in the furnace wall near the furnace mouth. Since it was sprayed downward, the endothermic reaction shown in Equation (3) occurred, and in fact, only the reaction heat from Equation (1) could be utilized. As described above, it is clear that implementation of the invention is advantageously suited in bottom-blown converters or in top-bottom blown converters. (Example) Example 1 A top-bottom blowing converter with a furnace capacity of 5 tons as shown in FIG. Only one set of two facing each other was installed. The oxygen gas is 5Nm 3 /min from the bottom tuyere 2, 10Nm 3 /min from the top blow lance 6, and 5Nm 3 /min from the secondary combustion oxygen supply tuyere 5 .
min was supplied respectively. After charging approximately 5 tons of hot metal into a converter under the conditions shown in Table 1, blowing with the oxygen gas described above is continued, and the temperature of the molten metal is determined when the carbon concentration [%C] reaches approximately 0.10%. During this time, when [%C] was approximately 1%, gas was sampled from the tap hole, and the gas composition was analyzed using gas chromatography.
The refining results shown in Table 1 were obtained.
【表】
これに対して酸素供給は上述の条件に揃えて
20Nm3／minとし、全量を底吹き羽口２のみから
供給する従来の底吹き吹錬（従来例１，２）と
5Nm3／minを底吹きランス２よりまた、15N
m3／minを上吹きランス６から供給する従来の上
底吹き吹錬（従来例３，４）とについても同様な
測定を行い、成績を比較した。
装入溶銑の条件すなわち温度、Ｃ，Si濃度とも
ほぼ同一の範囲内にあり、かつ吹止め時のＣ濃度
も同一範囲であつても吹止時温度は従来例１，２
と比べて50〜70℃、同じく３，４と比べて30〜50
℃高くなつている。
またガス中のCO2濃度も明らかに高く、２次燃
焼の効果が明確に現われている。
２次燃焼率をCO2／CO＋CO2×100（％）で定義すれ
ば従来例１，２では3.4〜5.4％、同３，４でも
11.1〜12.2％であるのに対し、この発明の場合に
は26.5〜34.5％まで上昇している。
この実施例では２次燃焼用酸素を5Nm3／min
一定としたため、高々34.5％の２次燃焼率であつ
たが、別に行つた実験で10Nm3／minまで２次燃
焼用酸素を増加した時には（脱炭用酸素は15N
m3／min）２次燃焼率は62％まで上昇し、溶鋼温
度は1740℃以上を記録した。
実施例 ２
実施例１と同じ５トン転炉を用いて、同一の２
次燃焼用羽口を使用し、酸素を供給しつつ、溶鋼
温度が1550〜1600℃になるようにクロム鉱石とコ
ークス塊を炉口から投入した。コークス塊は25
Kg／min、クロム鉱石は温度の高低により投入量
を調整した。この事例はクロム鉱石中のクロム酸
化物を炭素還元して、溶鉄中に回収する目的に従
い、クロム鉱石を大量に短時間に投入して生産性
の向上を期するものである。
脱炭用酸素は15Nm3／minとし、２次燃焼酸素
供給用羽口５を通して10Nm3／minの酸素を供給
したところクロム鉱石は45〜50Kg／minの投入速
度で温度は上記範囲に収つた。しかし第４図に示
した溶鉄に直接酸素気流が当たる方式の羽口では
25〜30Kg／minの投入速度に止まり、また２次燃
焼酸素供給用羽口５を使用せずに全酸素量は同一
条件にした場合には、15〜20Kg／minの投入速度
しか達成できなかつた。
この例から明らかなように、２次燃焼酸素供給
用羽口を設置する位置とその酸素気流の方向をこ
の発明のようにしなければ高い２次燃焼率が得ら
れず、したがつて鉱石投入速度も小さくなること
がわかる。
（発明の効果）
この発明によれば、溶鉄の脱炭精錬によつて生
成するCOガスの適切な２次燃焼が導かれそれに
よる有効な溶鉄の加熱が可能になる。[Table] On the other hand, oxygen supply is adjusted to the above conditions.
20Nm 3 /min, and the entire amount is supplied only from the bottom blowing tuyere 2 (conventional examples 1 and 2).
5Nm 3 /min from bottom blowing lance 2 and 15N
Similar measurements were made for conventional top-bottom blowing (conventional examples 3 and 4) in which m 3 /min was supplied from the top blowing lance 6, and the results were compared. Even though the charging hot metal conditions, that is, temperature, C, and Si concentrations are in almost the same range, and the C concentration at blow-off is also in the same range, the blow-off temperature is lower than that of conventional examples 1 and 2.
50~70℃ compared to 3 and 4, and 30~50℃ compared to 3 and 4.
The temperature is rising. The CO 2 concentration in the gas was also clearly high, clearly showing the effect of secondary combustion. If the secondary combustion rate is defined as CO 2 /CO + CO 2 × 100 (%), it is 3.4 to 5.4% in Conventional Examples 1 and 2, and 3.4 to 5.4% in Conventional Examples 3 and 4.
While it is 11.1-12.2%, it increases to 26.5-34.5% in the case of this invention. In this example, the oxygen for secondary combustion is 5Nm 3 /min.
Since the secondary combustion rate was kept constant, the secondary combustion rate was at most 34.5%, but in a separate experiment, when the secondary combustion oxygen was increased to 10Nm 3 /min (the decarburization oxygen was 15Nm 3 /min), the secondary combustion rate was 34.5%.
m 3 /min) The secondary combustion rate rose to 62%, and the molten steel temperature was recorded at over 1740°C. Example 2 Using the same 5-ton converter as in Example 1, the same 2
Using tuyeres for secondary combustion, chromium ore and coke lumps were introduced through the furnace mouth while supplying oxygen so that the temperature of the molten steel was 1550 to 1600°C. Coke lump is 25
Kg/min, and the input amount of chromium ore was adjusted depending on the temperature. In this case, chromium oxide in chromium ore is reduced with carbon and recovered in molten iron, and a large amount of chromium ore is introduced in a short period of time to improve productivity. Oxygen for decarburization was set at 15 Nm 3 /min, and when 10 Nm 3 /min of oxygen was supplied through the tuyere 5 for secondary combustion oxygen supply, the temperature of the chromium ore was within the above range at an input rate of 45 to 50 kg/min. . However, with the tuyeres shown in Figure 4, where the oxygen stream hits the molten iron directly,
If the injection speed remains at 25 to 30 kg/min, and if the secondary combustion oxygen supply tuyere 5 is not used and the total oxygen amount is kept the same, the injection speed will only be 15 to 20 kg/min. Ta. As is clear from this example, a high secondary combustion rate cannot be obtained unless the location of the secondary combustion oxygen supply tuyeres and the direction of the oxygen flow are as in this invention, and therefore the ore input rate is You can see that it also becomes smaller. (Effects of the Invention) According to the present invention, appropriate secondary combustion of CO gas generated by decarburization and refining of molten iron is induced, thereby making it possible to effectively heat the molten iron.
第１図はこの発明に従う２次燃焼方法の実施要
領を示す上底吹き転炉の断面図、第２図は炉内反
応挙動を示す模式図であり、第３図は転炉の底吹
きガス流量がスラグ／メタル間温度差に及ぼす影
響を示すグラフであり、第４図は従来法の説明図
である。
１……転炉炉体、２……底吹き羽口、３……溶
鉄、４……スラグ、５……２次燃焼用羽口、６…
…脱炭用酸素上吹きランス、７……２次燃焼用の
酸素供給ノズル、８……２次燃焼用羽口のクーラ
ントガス入口。
FIG. 1 is a cross-sectional view of a top-bottom blowing converter showing the procedure for carrying out the secondary combustion method according to the present invention, FIG. 2 is a schematic diagram showing reaction behavior in the furnace, and FIG. 3 is a bottom-blowing converter gas FIG. 4 is a graph showing the influence of flow rate on the temperature difference between slag and metal, and FIG. 4 is an explanatory diagram of the conventional method. 1... Converter furnace body, 2... Bottom blowing tuyere, 3... Molten iron, 4... Slag, 5... Tuyere for secondary combustion, 6...
...Oxygen top-blowing lance for decarburization, 7...Oxygen supply nozzle for secondary combustion, 8...Coolant gas inlet of tuyere for secondary combustion.
Claims (1)
精錬容器の内部で酸化して発生する一酸化炭素ガ
スを、精錬容器内で更に二酸化炭素ガスになるま
で酸化し、その反応熱を溶鉄に伝える、いわゆる
２次燃焼法による溶鉄の加熱に際し、 ２次燃焼反応用の酸素ガスを、その気流の吹出
し方向が溶鉄浴と接触しない向きとしてスラグ中
に供給することを特徴とする、２次燃焼による溶
鉄の加熱方法。 ２ 精錬容器が底吹き転炉または上底吹き転炉で
ある１記載の方法。[Scope of Claims] 1 Carbon monoxide gas generated by oxidation of carbon in molten iron or a separately added carbon source inside a refining container is further oxidized to carbon dioxide gas in the refining container, and the reaction is performed. When heating the molten iron by the so-called secondary combustion method, which transfers heat to the molten iron, oxygen gas for the secondary combustion reaction is supplied into the slag in such a way that the direction of the airflow does not come into contact with the molten iron bath. , a method of heating molten iron by secondary combustion. 2. The method according to 1, wherein the refining vessel is a bottom-blowing converter or a top-bottom blowing converter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20565784A JPS6184311A (en) | 1984-10-02 | 1984-10-02 | Method for heating molten iron by secondary combustion method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20565784A JPS6184311A (en) | 1984-10-02 | 1984-10-02 | Method for heating molten iron by secondary combustion method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6184311A JPS6184311A (en) | 1986-04-28 |
| JPH0413404B2 true JPH0413404B2 (en) | 1992-03-09 |
Family
ID=16510522
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20565784A Granted JPS6184311A (en) | 1984-10-02 | 1984-10-02 | Method for heating molten iron by secondary combustion method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6184311A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH079017B2 (en) * | 1986-05-29 | 1995-02-01 | 日本鋼管株式会社 | Melt reduction method |
| JPH02156011A (en) * | 1988-12-07 | 1990-06-15 | Sumitomo Metal Ind Ltd | Oxygen converter steelmaking method in converter providing furnace shoulder tuyere |
| KR100242565B1 (en) * | 1991-09-20 | 2000-03-02 | 제이 엠. 플로이드 | Process for production of iron |
-
1984
- 1984-10-02 JP JP20565784A patent/JPS6184311A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6184311A (en) | 1986-04-28 |
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