JP5477274B2 - Smelting furnace - Google Patents

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JP5477274B2
JP5477274B2 JP2010278507A JP2010278507A JP5477274B2 JP 5477274 B2 JP5477274 B2 JP 5477274B2 JP 2010278507 A JP2010278507 A JP 2010278507A JP 2010278507 A JP2010278507 A JP 2010278507A JP 5477274 B2 JP5477274 B2 JP 5477274B2
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JP2012126949A (en
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礼太 齊藤
道丈 藤原
正記 今西
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Description

本発明は、例えば横吹き羽口を有する精錬炉に関するものである。   The present invention relates to a refining furnace having, for example, a horizontal blowing tuyere.

ステンレス鋼の精錬では、AOD（Argon Oxygen Degassing）炉で代表される横吹き羽口を有する精錬容器が使用され、この羽口部からアルゴンや酸素、あるいはその混合ガスを吹き込み、脱炭、還元及び成分調整が行われる。   In the refining of stainless steel, a refining vessel with a horizontal blowing tuyere represented by an AOD (Argon Oxygen Degassing) furnace is used, and argon, oxygen, or a mixed gas thereof is blown from the tuyere to decarburize, reduce and Component adjustment is performed.

このAOD炉を用いた精錬は、その精錬条件が極めて高温で、かつ高侵食性の溶滓が使用されることから、炉内の耐火物が溶損され易い。また、横吹き羽口からガスを吹き込む場合、炉内では一般の底吹き撹拌とは異なると推定される激しいガス対流、溶鋼流が発生しているので、羽口部とその上方に局部的な溶損が発生する。   In the refining using this AOD furnace, since the refining conditions are extremely high and a highly erosive hot metal is used, the refractory in the furnace is easily melted. In addition, when gas is blown from the side-blown tuyere, intense gas convection and molten steel flow, which is estimated to be different from general bottom-blown agitation, are generated in the furnace. Melting occurs.

一方、炉内に内張りされた煉瓦は、使用限界を超えると解体されて再構築されるが、この解体時に発生する廃棄耐火物は構築時のおよそ４０ 〜 ６０ %となっている。   On the other hand, bricks lined in the furnace are demolished and reconstructed when the usage limit is exceeded, but the waste refractory generated at the time of demolition is approximately 40 to 60% of that at the time of construction.

そこで、羽口の周りと羽口の上方に位置する煉瓦を耐溶損性に優れたマグネシア−クロム（MgO・Cr2O3）煉瓦（以下、マグクロ系煉瓦という）とし、他の部分は安価なドロマイト系煉瓦とする構造が開示されている（例えば特許文献１）。このような構造とすることにより、横吹き羽口を有する精錬炉における耐火物の局所的な激しい溶損を抑制して炉全体の寿命を伸ばすことができる。 Therefore, the bricks around the tuyere and above the tuyere are made of magnesia-chromium (MgO · Cr 2 O 3 ) bricks (hereinafter referred to as magcro bricks) with excellent resistance to melting damage, and the other parts are inexpensive. The structure made into a dolomite-type brick is disclosed (for example, patent document 1). By adopting such a structure, it is possible to extend the life of the entire furnace by suppressing local severe melting of the refractory in the refining furnace having the side blow tuyere.

しかしながら、特許文献１に開示された構造では、解体時に溶け残った耐火煉瓦を廃棄する際、前記マグクロ系煉瓦からは、六価クロムが発生して人体や環境への悪影響が危惧される。従って、環境上の問題から解決を迫られている。   However, in the structure disclosed in Patent Document 1, when discarding the refractory bricks remaining undissolved at the time of dismantling, hexavalent chromium is generated from the magcro bricks, and there is a concern about adverse effects on the human body and the environment. Therefore, there is an urgent need to solve it due to environmental problems.

クロムフリー化として、マグクロ系煉瓦の代替に、精錬容器の内張り煉瓦を安価で経済性に優れたドロマイト系煉瓦にするものがある。しかしながら、ドロマイト系煉瓦の溶損速度は、マグクロ系煉瓦に比べて速いため、マグクロ系煉瓦に代えてドロマイト系煉瓦を設ける部分の煉瓦厚さを長尺化する必要がある。   As an alternative to chrome-free bricks, there is a chrome-free brick that replaces the lining bricks of smelting containers with dolomite bricks that are inexpensive and economical. However, since the melting rate of dolomite bricks is faster than that of magchrom bricks, it is necessary to lengthen the brick thickness at the portion where dolomite bricks are provided instead of magchrom bricks.

煉瓦厚さを長尺化するとライニングコストを悪化させるだけでなく、炉容積が減少するので、１チャージ当りの精錬量が減少し、また湯面の上昇によりスロッピングの危険性が高まる。従って、送酸速度を減じる必要があり、処理時間延長等、生産性を悪化させる。   Increasing the brick thickness not only deteriorates the lining cost, but also reduces the furnace volume, thereby reducing the amount of refining per charge and increasing the risk of slopping due to the rise of the molten metal surface. Therefore, it is necessary to reduce the acid feed rate, which deteriorates productivity such as extending the processing time.

炉内の煉瓦厚さに関しては、羽口近傍での煉瓦厚さを厚くすると同時に、羽口上方の煉瓦を大きな傾斜角で引っ込める構造が開示されているが（例えば特許文献２）、この羽口上方の煉瓦を大きな傾斜角で引っ込める構造は、煉瓦の施工が複雑になる。   Regarding the brick thickness in the furnace, a structure is disclosed in which the brick thickness in the vicinity of the tuyere is increased and at the same time the brick above the tuyere is retracted with a large inclination angle (for example, Patent Document 2). The construction of retracting the upper brick with a large inclination angle makes the construction of the brick complicated.

特開２００７−２２６９号公報Japanese Patent Laid-Open No. 2007-2269 特開昭６３−２６２４１０号公報JP-A 63-262410

本発明が解決しようとする問題点は、羽口周りと羽口の上方位置にある煉瓦を耐溶損性の高いマグクロ系煉瓦として寿命の延長を図る場合、溶け残った耐火煉瓦を廃棄する際、含有クロムによる環境問題が懸念されるという点である。これに対して、マグクロ系煉瓦の代替にドロマイト系煉瓦を使用する場合、煉瓦厚さの長尺化に伴う問題があるという点である。   When the problem to be solved by the present invention is to extend the life of the bricks around the tuyere and above the tuyere as a highly melt-resistant magcro brick, when discarding the undissolved refractory bricks, There are concerns about environmental problems caused by the chromium content. On the other hand, when dolomite brick is used as an alternative to magcro brick, there is a problem with increasing the thickness of the brick.

本発明の精錬炉は、
羽口を有する精錬炉において、マグクロ系耐火物を廃棄物とすることなく、従来よりもライニングコストをかけずに炉寿命を向上させるために、
炉壁に羽口が設けられた精錬炉において、
炉壁に内張りされた耐火煉瓦のうちで、鉄皮側に設けられるパーマネント煉瓦よりも炉内側に施工されるワーク煉瓦の、少なくとも羽口部の上方部分における所定範囲を稼動面側と背面側に２分し、前記２分した部分の稼動面側にはCr2O3を含有するマグクロ系煉瓦を使用し、背面側にはCr2O3を含有しないドロマイト系煉瓦を使用して築炉施工する際に、
炉容積で決まる段毎の、前記パーマネント煉瓦の炉内側端面から前記稼動面側の煉瓦の炉内側端面までの長さをワーク煉瓦の有効厚みとした場合、背面側の煉瓦と稼動面側の煉瓦それぞれの厚さが占める割合を前記有効厚みの２０〜８０％としたことを最も主要な特徴としている。 The refining furnace of the present invention is
In a refining furnace with tuyere, in order to improve the life of the furnace without using magcro refractories as waste and lining costs more than before,
In a refining furnace with a tuyere on the furnace wall,
Among the refractory bricks lined on the furnace wall, the work bricks constructed on the inner side of the furnace than the permanent bricks provided on the iron skin side, at least the predetermined range in the upper part of the tuyere is on the working surface side and back side Construction work was done using magchrom bricks containing Cr 2 O 3 on the working surface side and dolomite bricks not containing Cr 2 O 3 on the back side. When doing
When the length from the furnace inner end face of the permanent brick to the furnace inner end face of the working surface side brick is the effective thickness of the work brick for each stage determined by the furnace volume, the back side brick and the working side brick The main feature is that the ratio of each thickness is 20 to 80% of the effective thickness .

本発明の精錬炉は、ワーク煉瓦の、少なくとも羽口部の上方部分における所定範囲を稼動面側と背面側に２分し、前記２分した部分の稼動面側にはCr2O3を含有するマグクロ系煉瓦を使用するので、耐火物の溶損を抑制できる。また、炉の解体時には、稼動面側のマグクロ系煉瓦は溶損され、背面側のCr2O3を含有しないドロマイト系煉瓦だけを解体するので、含有クロムによる環境問題は発生しない。 The refining furnace of the present invention divides a predetermined range at least in the upper part of the tuyere of the work brick into two parts on the working surface side and the back side, and contains the Cr 2 O 3 on the working surface side of the two- divided part. Since the magchrom bricks that are used are used, the refractory can be prevented from being melted. Further, when the furnace is dismantled, the magchrom bricks on the working surface side are melted and only the dolomite bricks that do not contain Cr 2 O 3 on the back side are dismantled, so there is no environmental problem due to the chromium content.

本発明は、溶損の激しい部分の稼動面側煉瓦を、Cr2O3を含有するマグクロ系煉瓦を使用するので、耐火物の溶損を抑制でき、従来よりも炉寿命を向上させることができる。また、炉の解体時には、稼動面側のマグクロ系煉瓦は溶損されているので、背面側のCr2O3を含有しないドロマイト系煉瓦だけを解体することになって、含有クロムによる環境問題が発生することがない。 Since the present invention uses a magcro brick containing Cr 2 O 3 as the working surface side brick in the part where the erosion is severe, it can suppress the refractory erosion and improve the life of the furnace than before. it can. In addition, when the furnace was dismantled, the magchrom bricks on the working surface side were melted, so only the dolomite bricks that did not contain Cr 2 O 3 on the back side were dismantled, which caused environmental problems due to the chromium content. It does not occur.

本発明の精錬炉における耐火物の施工例を示す羽口側部分の縦断面図である。It is a longitudinal cross-sectional view of the tuyere side part which shows the construction example of the refractory in the refining furnace of this invention. 本発明の精錬炉における羽口部の上方部分に施工する耐火物の説明図である。It is explanatory drawing of the refractory constructed to the upper part of a tuyere part in the refining furnace of this invention. 図２を高さ方向に施工する場合の一例を示した図である。It is the figure which showed an example in the case of constructing FIG. 2 in the height direction. 従来の精錬炉における耐火物の施工例（従来例１）を示す羽口側部分の縦断面図である。It is a longitudinal cross-sectional view of a tuyere side part which shows the construction example (conventional example 1) of the refractory in the conventional refining furnace. 従来の精錬炉における耐火物の施工例（従来例２）を示す羽口側部分の縦断面図である。It is a longitudinal cross-sectional view of a tuyere side part which shows the construction example (conventional example 2) of the refractory in the conventional refining furnace.

本発明では、マグクロ系耐火物を廃棄物とすることなく、従来よりもライニングコストをかけずに炉寿命を向上させるという目的を、鉄皮側のパーマネント煉瓦よりも炉内側のワーク煉瓦の少なくとも羽口部の上方部分を稼動面側と背面側に２分し、その稼動面側にはマグクロ系煉瓦を、背面側にはドロマイト系煉瓦を使用することで実現した。   The purpose of the present invention is to improve the life of the furnace without using magcro-based refractories as waste and without increasing the lining cost compared to the prior art, and at least the wing of the work brick inside the furnace than the permanent brick on the iron skin side. It was realized by dividing the upper part of the mouth into two parts, the working surface side and the back side, and using magchrom bricks on the working surface side and dolomite bricks on the back side.

以下、本発明の精錬炉を、羽口側部分の縦断面図を示した図１を用いて説明する。
１は炉壁に横吹き羽口２が設けられた本発明の精錬炉で、鉄皮１ａ側にパーマネント煉瓦３を、このパーマネント煉瓦３の炉内側にワーク煉瓦４が内張り施工されて炉壁を形成している。 Hereinafter, the refining furnace of the present invention will be described with reference to FIG. 1 showing a longitudinal sectional view of a tuyere side portion.
1 is a refining furnace according to the present invention in which a horizontal blow tuyere 2 is provided on the furnace wall. A permanent brick 3 is installed on the iron skin 1a side, and a work brick 4 is lined on the furnace inner side of the permanent brick 3 so that the furnace wall is covered. Forming.

本発明では、前記構成からなる炉壁のうち、横吹き羽口２部の上方部分の所定範囲、例えば炉底から６段目から２５段目までの前記ワーク煉瓦４を、稼動面側と背面側に２分している。なお、この所定範囲は、精錬時における横吹き羽口２から吹き出す撹拌用ガスの流量等によって、適宜決定するものである。   In the present invention, among the furnace walls having the above-described configuration, the work bricks 4 in a predetermined range in the upper portion of the horizontal blow tuyere 2 part, for example, the sixth to 25th stages from the furnace bottom are arranged on the working surface side and the back surface. 2 minutes to the side. This predetermined range is appropriately determined depending on the flow rate of the stirring gas blown out from the horizontal blowing tuyere 2 during refining.

そして、この２分した部分の稼動面側には耐溶損性に優れたマグクロ系煉瓦４ａを使用し、背面側には安価で経済性に優れ、含有クロムによる環境問題が発生することがないドロマイト系煉瓦４ｂを使用している。   And the dolomite which uses the magchrom brick 4a which was excellent in the melt resistance on the working surface side of the bisected portion and is inexpensive and excellent in economy on the back side and which does not cause environmental problems due to the contained chromium. The system brick 4b is used.

なお、横吹き羽口２部（炉底から２段目から５段目）は、従来と同様、背面側及び稼動面側共にマグクロ系煉瓦４ａを使用している。   In addition, the 2 parts of the horizontal blowing tuyere (2nd to 5th steps from the bottom of the furnace) use magchrom bricks 4a on the back side and the operation side as in the conventional case.

前記稼動面側のマグクロ系煉瓦４ａは、例えばCaOが０質量％、MgOが５０質量％以上含み、耐溶損性を考慮してCr2O3が１５質量％以上含むものを使用する。一方、前記背面側のドロマイト系煉瓦４ｂは、CaOが３０〜５０質量％、MgOが７０〜５０質量％含み、含有クロムによる環境問題が発生することがないようにCr2O3が０質量％のものを使用する。 As the working surface side magcro brick 4a, for example, a CaO content of 0% by mass, a MgO content of 50% by mass or more, and a Cr 2 O 3 content of 15% by mass or more is used in consideration of resistance to melting. On the other hand, the dolomite brick 4b on the back side contains 30 to 50% by mass of CaO and 70 to 50% by mass of MgO, and 0% by mass of Cr 2 O 3 so as not to cause environmental problems due to the contained chromium. Use one.

前記ワーク煉瓦４の有効厚みである、前記パーマネント煉瓦４の炉内側端面から前記稼動面側のマグクロ系煉瓦４ａの炉内側端面までの長さは、段毎に炉容積等で決まるものである。   The length from the furnace inner end face of the permanent brick 4 to the furnace inner end face of the working surface side magcro brick 4a, which is the effective thickness of the work brick 4, is determined by the furnace volume for each stage.

本発明では、段毎の前記マグクロ系煉瓦４ａと前記ドロマイト系煉瓦４ｂの厚さは、図２に示すように、それぞれ前記有効厚みの２０〜８０％とする。そして、この範囲内で、稼動面側のマグクロ系煉瓦４ａが先行溶損されて背面側のドロマイト系煉瓦４ｂが残り、マグクロ系煉瓦４ａのクロム分が鋼中で還元リサイクルされるように、溶損速度に応じてマグクロ系煉瓦４ａの厚みを設定するのである。 In the present invention, the thickness of the Magukuro system brick 4a of each stage the dolomite brick 4b, as shown in FIG. 2 shall be the 20-80% of each of the effective thickness. Within this range, the magchrom brick 4a on the working surface side is preliminarily melted and the dolomite brick 4b on the back side remains, so that the chromium content of the magcro brick 4a is reduced and recycled in the steel. The thickness of the mug brick 4a is set according to the loss speed.

このようにすることで、ドロマイト系煉瓦４ｂのマグクロ系煉瓦４ａに対する溶損性の劣位を克服して、炉寿命を向上させることが可能になる。また、最終的に残る煉瓦（図１にハッチングを施した部分の煉瓦）はドロマイト系煉瓦４ｂだけとなって、マグクロ系煉瓦４ａの廃棄による環境汚染の問題がなくなる。   By doing in this way, it becomes possible to overcome the inferior erosion resistance of the dolomite brick 4b to the magcro brick 4a and to improve the furnace life. Further, the last remaining brick (the hatched portion in FIG. 1) is only the dolomite brick 4b, and the problem of environmental pollution due to the disposal of the magcro brick 4a is eliminated.

図３に前記ワーク煉瓦４の高さ方向の積み方の模式図を示す。
図３に示したように、段毎の、前記背面側のドロマイト系煉瓦４ｂと前記稼動面側のマグクロ系煉瓦４ａの長さが、前記有効厚みの２０〜８０％の範囲内で交互に長短となるようにし、上下段で挟む千鳥構造とすれば、煉瓦の抜け落ちを防止することができる。 FIG. 3 shows a schematic diagram of how the work bricks 4 are stacked in the height direction.
As shown in FIG. 3, the lengths of the dolomite bricks 4b on the back side and the magcro bricks 4a on the working surface side are alternately short and long within a range of 20 to 80% of the effective thickness. If the zigzag structure is sandwiched between the upper and lower stages, it is possible to prevent the bricks from falling off.

上記本発明の効果を確認するために行った実施条件を下記表１に、実施結果を下記表２に示す。ここで、表１中の有効煉瓦厚さとは、炉内に施工した段毎のワーク煉瓦の煉瓦長さに占めるマグクロ系煉瓦の厚さの割合（図２参照）を示したものである。   The implementation conditions performed to confirm the effects of the present invention are shown in Table 1 below, and the implementation results are shown in Table 2 below. Here, the effective brick thickness in Table 1 indicates the ratio (see FIG. 2) of the thickness of the magcro bricks to the brick length of the work brick for each stage constructed in the furnace.

Figure 0005477274
Figure 0005477274

従来例１は、横吹き羽口を有するAOD炉のワーク煉瓦として、図４に示すように、全段マググロ系煉瓦を、従来例２は、図５に示すように、横吹き羽口部分を除いて全段ドロマイト系煉瓦を使用したものである。従来例２の煉瓦長さは、従来例１よりも長尺化した。なお、図４、図５中のハッチングを施した部分は、解体時に煉瓦が残存する範囲である。   As shown in FIG. 4, the conventional example 1 has a whole-stage maggro brick as a work brick of an AOD furnace having a horizontal blowing tuyere, and the conventional example 2 has a side blowing tuyere part as shown in FIG. Except for all-stage dolomite bricks. The brick length of Conventional Example 2 is longer than that of Conventional Example 1. In addition, the hatched part in FIGS. 4 and 5 is a range where the brick remains at the time of dismantling.

これに対し、比較例１〜４及び発明例１〜１４は、炉底から６段目から２５段目までのワーク煉瓦の稼動面側にマグクロ系煉瓦を、背面側にドロマイト系煉瓦を施工したものである。このうち、比較例１、２及び発明例１〜７は稼動面側と背面側に施工した二種類の煉瓦を従来の施工方法で築炉したもの、比較例３、４及び発明例８〜１４は稼動面側と背面側に施工した二種類の煉瓦を、図３のように千鳥積みにして築炉したものである。 In contrast, Comparative Examples 1-4 and Invention Examples 1 to 1 4, the Magukuro based bricks from sixth stage from the furnace bottom in the operation surface side of the workpiece brick up to 25 stage, applying a dolomite bricks on the back side It is a thing. Among these, Comparative Examples 1 and 2 and Invention Examples 1 to 7 are the ones in which two types of bricks constructed on the working surface side and the back surface side are constructed by a conventional construction method, Comparative Examples 3 and 4 and Invention Examples 8 to 14. Fig. 3 shows two types of bricks constructed on the working surface side and the back surface side and built in a staggered manner as shown in Fig. 3.

上記従来例及び発明例のように築炉施工したAOD炉で、SUS304に代表されるステンレス鋼を以下の条件で精錬した。   Stainless steel represented by SUS304 was refined under the following conditions in the AOD furnace constructed and constructed as in the above-described conventional examples and invention examples.

撹拌用のガス種：Arガス
撹拌用のガスの流量：３０００ Nm3／hr程度
スラグの塩基度（CaO／SiO2）：概ね１．３〜２．０
MgO／CaO：０．６程度
精錬時の最高到達温度：概ね１７００℃ Gas type for stirring: Ar gas Flow rate of stirring gas: about 3000 Nm 3 / hr Basicity of slag (CaO / SiO 2 ): about 1.3 to 2.0
MgO / CaO: about 0.6 Maximum temperature reached during refining: 1700 ° C

ライニングコストと精錬回数から、１チャージ当たりのコストを、従来例１を基準に指数化したものを下記表２に示した。   Table 2 below shows the cost per charge indexed from the lining cost and the number of times of refining based on the conventional example 1.

Figure 0005477274
Figure 0005477274

従来例２では、ドロマイト系煉瓦の厚さを従来例１よりも長尺化しているが、マグクロ系煉瓦に比べてドロマイト系煉瓦は安価であるため、ライニングコストは低くなる。しかしながら、ドロマイト系煉瓦の方がマグクロ系煉瓦よりも耐溶損性に劣るため、従来例１よりも従来例２の方が、炉寿命が低位となり、その分１チャージ当たりのコストは高位となる。   In Conventional Example 2, the thickness of the dolomite brick is made longer than that in Conventional Example 1. However, since dolomite brick is less expensive than magchrom brick, the lining cost is low. However, since the dolomite brick is inferior in resistance to melting damage than the magchrom brick, the furnace life of the conventional example 2 is lower than that of the conventional example 1, and the cost per charge is higher accordingly.

これに対して、比較例１〜４及び発明例１〜１４は、ワーク煉瓦の稼動面側にマグクロ系煉瓦を施工することにより、従来例２よりもライニングコストは若干増加するが、炉寿命が延びるため、１チャージ当たりのコストは、従来の煉瓦施工を施した従来例１、２よりも低位となり、コストを抑え炉寿命向上が図れた。 In contrast, Comparative Examples 1-4 and Invention Examples 1 to 1 4, by applying a Magukuro system bricks in the operation surface side of the workpiece brick, but lining cost than the conventional example 2 is slightly increased, the furnace life Therefore, the cost per charge was lower than those of the conventional examples 1 and 2 where the conventional brick construction was applied, and the cost was reduced and the life of the furnace was improved.

但し、比較例１、２及び発明例１〜７は、二種類の煉瓦を組み合わせるので、従来例１、２と比べて煉瓦の抜け落ち頻度は増加するが、比較例３、４及び発明例８〜１４のように、二種類の煉瓦を千鳥積みにすることで、比較例１、２及び発明例１〜７はもとより従来例１、２よりも煉瓦の抜け落ち頻度が減り、１チャージ当たりのコストを低くすることができた。 However, since Comparative Examples 1 and 2 and Invention Examples 1 to 7 combine two types of bricks, the falling frequency of bricks increases compared to Conventional Examples 1 and 2, but Comparative Examples 3 and 4 and Invention Examples 8 to As shown in FIG. 14, by staggering two types of bricks, the falling frequency of bricks is reduced compared to Comparative Examples 1 and 2 and Invention Examples 1 to 7 as well as Conventional Examples 1 and 2, and the cost per charge is reduced. I was able to lower it.

また、比較例のうち、有効煉瓦厚さが１０％の比較例１、３は、マグクロ系煉瓦の比率が少ないので、比較例、発明例のなかではトータル煉瓦の溶損速度が速く、炉寿命が低下して１チャージ当たりのコストが高くなった。 Further, among the comparative examples, comparative effective brick thickness is 10% Example 1, 3, since the small proportion of Magukuro based brick, Comparative Example, faster erosion rate of total brick Among the invention examples, the furnace life Decreased and the cost per charge increased.

一方、比較例２、４及び発明例１〜１４のように有効煉瓦厚さを２０〜９０％と増加させれば、溶損を抑えることができ、１チャージ当たりのコストを従来例１、２よりも低くできた。 On the other hand, if the effective brick thickness is increased to 20 to 90% as in Comparative Examples 2 and 4 and Invention Examples 1 to 14 , melting loss can be suppressed, and the cost per charge is reduced to the conventional examples 1 and 2. Can be lower.

しかしながら、比較例２、４のように、有効煉瓦厚さを９０％とすると、１チャージ当たりのコストは抑えられるものの、解体時における羽口部上方の廃棄煉瓦中にCr2O3が含まれるので、クロムフリー化を達成することができない。 However, as in Comparative Examples 2 and 4 , if the effective brick thickness is 90%, the cost per charge can be suppressed, but the waste brick above the tuyere at the time of dismantling contains Cr 2 O 3. Therefore, it is not possible to achieve chrome-free.

以上より、本発明においては、有効煉瓦厚さは、２０〜８０％とすることが望ましいことが分かる。   From the above, it can be seen that in the present invention, the effective brick thickness is preferably 20 to 80%.

本発明は上記の例に限らず、請求項に記載された技術的思想の範疇であれば、適宜実施の形態を変更しても良いことは言うまでもない。   The present invention is not limited to the above example, and it goes without saying that the embodiments may be changed as appropriate within the scope of the technical idea described in the claims.

例えば上記の例では横吹き羽口２を有する精錬炉１について説明したが、斜め吹き込み、底吹き羽口の精錬炉に適用することも可能である。   For example, in the above example, the refining furnace 1 having the horizontal blowing tuyere 2 has been described. However, the refining furnace 1 can also be applied to a refining furnace having oblique blowing and bottom blowing tuyere.

１ 精錬炉
２ 横吹き羽口
３ パーマネント煉瓦
４ ワーク煉瓦
４ａ マグクロ系煉瓦
４ｂ ドロマイト系煉瓦 DESCRIPTION OF SYMBOLS 1 Refining furnace 2 Horizontal blowing tuyere 3 Permanent brick 4 Work brick 4a Magcro brick 4b Dolomite brick

Claims (3)

炉壁に羽口が設けられた精錬炉において、
炉壁に内張りされた耐火煉瓦のうちで、鉄皮側に設けられるパーマネント煉瓦よりも炉内側に施工されるワーク煉瓦の、少なくとも羽口部の上方部分における所定範囲を稼動面側と背面側に２分し、前記２分した部分の稼動面側にはCr2O3を含有するマグクロ系煉瓦を使用し、背面側にはCr2O3を含有しないドロマイト系煉瓦を使用して築炉施工する際に、
炉容積で決まる段毎の、前記パーマネント煉瓦の炉内側端面から前記稼動面側の煉瓦の炉内側端面までの長さをワーク煉瓦の有効厚みとした場合、背面側の煉瓦と稼動面側の煉瓦それぞれの厚さが占める割合を前記有効厚みの２０〜８０％としたことを特徴とする横吹き精錬炉。 In a refining furnace with a tuyere on the furnace wall,
Among the refractory bricks lined on the furnace wall, the work bricks constructed on the inner side of the furnace than the permanent bricks provided on the iron skin side, at least the predetermined range in the upper part of the tuyere is on the working surface side and back side Construction work was done using magchrom bricks containing Cr 2 O 3 on the working surface side and dolomite bricks not containing Cr 2 O 3 on the back side. When doing
When the length from the furnace inner end face of the permanent brick to the furnace inner end face of the working surface side brick is the effective thickness of the work brick for each stage determined by the furnace volume, the back side brick and the working side brick A horizontal blowing smelting furnace characterized in that a ratio of each thickness is 20 to 80% of the effective thickness . 前記背面側のドロマイト系煉瓦として、質量％でCaOが３０〜５０％、MgOが７０〜５０％、Cr2O3が０％のものを、前記稼動面側のマグクロ系煉瓦として、CaOが０％、MgOが５０％以上、Cr2O3が１５％以上含むものを使用することを特徴とする請求項１に記載の横吹き精錬炉。 As the dolomite brick on the back side, CaO is 30 to 50% by mass, MgO is 70 to 50%, and Cr 2 O 3 is 0%. The horizontal blown smelting furnace according to claim 1 , wherein the MgO contains 50% or more of MgO and 15% or more of Cr 2 O 3 . 段毎の、前記背面側の煉瓦と前記稼動面側の煉瓦の長さが交互に長短となるようにし、上下段で挟む構造としたことを特徴とする請求項１又は２に記載の横吹き精錬炉。 The horizontal blowing according to claim 1 or 2 , wherein the back side brick and the working side brick are alternately lengthened and sandwiched between upper and lower stages for each stage. Refining furnace.
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