JP6540632B2 - Dephosphorization method of hot metal - Google Patents
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- JP6540632B2 JP6540632B2 JP2016166644A JP2016166644A JP6540632B2 JP 6540632 B2 JP6540632 B2 JP 6540632B2 JP 2016166644 A JP2016166644 A JP 2016166644A JP 2016166644 A JP2016166644 A JP 2016166644A JP 6540632 B2 JP6540632 B2 JP 6540632B2
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- 229910052751 metal Inorganic materials 0.000 title claims description 182
- 239000002184 metal Substances 0.000 title claims description 182
- 238000000034 method Methods 0.000 title claims description 47
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 150
- 239000001301 oxygen Substances 0.000 claims description 147
- 229910052760 oxygen Inorganic materials 0.000 claims description 147
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 62
- 229910052698 phosphorus Inorganic materials 0.000 claims description 62
- 239000011574 phosphorus Substances 0.000 claims description 62
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 52
- 239000007789 gas Substances 0.000 claims description 44
- 238000007664 blowing Methods 0.000 claims description 28
- 238000002347 injection Methods 0.000 claims description 28
- 239000007924 injection Substances 0.000 claims description 28
- 229910052742 iron Inorganic materials 0.000 claims description 26
- 239000007800 oxidant agent Substances 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 13
- 238000007654 immersion Methods 0.000 claims description 9
- 239000000126 substance Substances 0.000 claims description 7
- 230000001590 oxidative effect Effects 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 5
- 238000003672 processing method Methods 0.000 claims description 2
- 239000002893 slag Substances 0.000 description 32
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 28
- 239000003795 chemical substances by application Substances 0.000 description 22
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 20
- 238000002156 mixing Methods 0.000 description 20
- 238000006243 chemical reaction Methods 0.000 description 18
- 239000000292 calcium oxide Substances 0.000 description 14
- 235000012255 calcium oxide Nutrition 0.000 description 14
- 150000002222 fluorine compounds Chemical class 0.000 description 11
- 230000007423 decrease Effects 0.000 description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- 239000012159 carrier gas Substances 0.000 description 5
- 238000002485 combustion reaction Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000007667 floating Methods 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 3
- 239000012809 cooling fluid Substances 0.000 description 3
- 230000020169 heat generation Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000009628 steelmaking Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000005261 decarburization Methods 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 239000011823 monolithic refractory Substances 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000002203 pretreatment Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 239000012495 reaction gas Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 229910004261 CaF 2 Inorganic materials 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005262 decarbonization Methods 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000010436 fluorite Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000012447 hatching Effects 0.000 description 1
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910001392 phosphorus oxide Inorganic materials 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- VSAISIQCTGDGPU-UHFFFAOYSA-N tetraphosphorus hexaoxide Chemical compound O1P(O2)OP3OP1OP2O3 VSAISIQCTGDGPU-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Furnace Charging Or Discharging (AREA)
Description
本発明は、混銑車などの溶銑搬送容器における溶銑の脱燐処理方法に関する。 The present invention relates to a method of dephosphorizing hot metal in a hot metal transfer container such as a mixing wheel.
混銑車における溶銑脱燐処理において０．０１質量％程度といった低燐濃度まで脱燐処理を行うときには、従来媒溶剤の滓化促進を目的として蛍石（ＣａＦ２）等のフッ素化合物が使用されていた。製鋼工程で発生するスラグは、通常、路盤材等の土木工事材料として利用されるが、フッ素化合物を含有するスラグを路盤材等の土木工事材料として利用すると、スラグからフッ素が溶出して環境がフッ素で汚染されるおそれがある。このため、フッ素化合物を含有する脱燐スラグは、路盤材等の土木工事材料としての利用が制限され、産業廃棄物として埋立処分する等の処理をせざるを得ず、フッ素化合物を使用することは、かえって製造コストを上昇させる要因となる。 When performing dephosphorization processing to a low phosphorus concentration such as about 0.01% by mass in hot metal dephosphorization processing in a mixing car, a fluorine compound such as fluorite (CaF 2 ) is conventionally used for the purpose of promoting the hatching of the medium solvent. The Slag generated in the steelmaking process is usually used as civil engineering material such as roadbed material, but when slag containing a fluorine compound is used as civil engineering material such as roadway material, fluorine is eluted from the slag and the environment is May be contaminated with fluorine. For this reason, the dephosphorization slag containing a fluorine compound is restricted in the use as a civil engineering material such as a roadbed material etc., and it is obliged to carry out disposal such as landfill disposal as an industrial waste, and the fluorine compound is used. Is a factor that raises the manufacturing cost.
そこで、この問題を解消するために、フッ素化合物を使用せずに、溶銑を低燐濃度まで脱燐する方法が提案されている。例えば、特許文献１には、搬送容器に収容された溶銑に酸化剤及び媒溶剤を供給して溶銑中の燐を酸化除去する溶銑の脱燐処理方法において、媒溶剤としてフッ素化合物を含有しないＣａＯ含有物質を使用し、酸化剤とは独立して気体酸素を溶銑上に存在するスラグ中に吹き込む溶銑の脱燐処理方法が開示されている。この方法では、脱燐用の酸化剤とは独立して溶銑上に存在するスラグ中に気体酸素を吹き込むので、スラグ中に含まれる粒鉄と吹き込まれた気体酸素とが反応し、粒鉄の酸化反応による発熱と、生成した鉄酸化物によるスラグの融点低下効果とにより、スラグの固相率が低下し、脱燐処理末期であってもスラグの流動性が確保されることで、脱燐処理末期におけるスラグの流動性低下による脱燐反応の阻害を防止できる、とされている。しかしながら、この溶銑の脱燐処理方法においても、低燐濃度域での脱燐速度の低下を防止する効果は十分ではなく、溶銑の燐濃度をさらに低減できる方法が求められていた。 Therefore, in order to solve this problem, a method of dephosphorizing hot metal to a low phosphorus concentration without using a fluorine compound has been proposed. For example, in Patent Document 1, CaO not containing a fluorine compound as a solvent is disclosed in a method for dephosphorizing molten metal in which an oxidizing agent and a solvent are supplied to the metal contained in a transport container to oxidize and remove phosphorus in the metal. A method of dephosphorizing hot metal is disclosed, wherein the contained material is used and gaseous oxygen is blown into the slag present on the hot metal independently of the oxidizing agent. In this method, gaseous oxygen is blown into the slag present on the hot metal independently of the oxidant for dephosphorizing, so that the granular iron contained in the slag reacts with the gaseous oxygen blown into the slag, causing Since heat generation due to oxidation reaction and the melting point lowering effect of the slag due to the formed iron oxide lowers the solid phase ratio of the slag, and by securing the fluidity of the slag even at the end of the dephosphorization treatment, dephosphorization It is said that the inhibition of the dephosphorization reaction due to the decrease in slag fluidity at the end of treatment can be prevented. However, even in this method of dephosphorizing molten iron, the effect of preventing the decrease in dephosphorization rate in a low phosphorus concentration range is not sufficient, and a method capable of further reducing the phosphorus concentration of molten iron has been required.
また、特許文献２には、混銑車に収容された溶銑に脱珪処理及び脱燐処理を施す際に、ランスの高さ方向設置位置を調整することで、溶銑への気体酸素の吹き込みと、溶銑への気体酸素の上吹きとを、１つのランスで行う溶銑の予備処理方法が開示されている。この方法では、脱珪処理で気体酸素を溶銑中に吹き込むランスと、脱燐処理で気体酸素を溶銑に上吹きするランスとを１つのランスで行うので、設備費用の削減及び処理中の操作の簡便化が実現され、効率的に脱珪処理及び脱燐処理を行うことが可能となるとともに、気体酸素を上吹きしてＣＯガスを二次燃焼させる際に、従来の水冷上吹きランスよりも効率的に溶銑に熱を付与することができる、とされている。しかしながら、この溶銑の予備処理方法においては、脱燐処理末期の溶銑温度の低下を抑制するという効果は得られるとしても、低燐濃度域での脱燐速度の低下を防止するには十分ではなく、溶銑の燐濃度をさらに低減できる方法が求められていた。 Further, according to Patent Document 2, when the molten metal contained in the mixing car is subjected to the desiliconization processing and the dephosphorization processing, the injection position of gaseous lance to the molten metal is adjusted by adjusting the installation position of the lance in the height direction; A method of pre-treatment of molten metal is disclosed, in which a lance is used to top-blown gaseous oxygen to the molten metal. In this method, a lance for blowing gaseous oxygen into the molten metal in the desiliconization process and a lance for blowing the gaseous oxygen over the molten metal in the dephosphorization process are performed in one lance, thereby reducing equipment cost and operation during processing. Simplification is realized, and it becomes possible to perform desiliconization treatment and dephosphorization treatment efficiently, and it is possible to carry out the secondary combustion of CO gas by blowing the gaseous oxygen upward, compared to the conventional water-cooled upper blowing lance. It is said that heat can be efficiently applied to hot metal. However, in this hot metal pre-treatment method, although the effect of suppressing the decrease of the hot metal temperature at the end of the dephosphorization treatment can be obtained, it is not sufficient to prevent the reduction of the dephosphorization rate in the low phosphorus concentration region. There has been a need for a method that can further reduce the phosphorus concentration of hot metal.
さらに、特許文献３には、混銑車内に装入された溶銑中に、混銑車内の長手方向を指向して挿入される２本の浸漬ランスから酸素ガスや酸化鉄、ＣａＯ系フラックスなどからなる脱燐剤をキャリアガスとともに吹き込む溶銑の脱燐方法が開示されている。この方法によれば、浸漬ランスを１本で脱燐する方法に比べて、溶銑中へ脱燐剤を分散して供給できるので、脱燐剤の反応効率を向上しつつ高速で脱燐処理を行うことが可能となる、とされている。しかし、２本の浸漬ランスから脱燐剤の吹き込みを行うためには、脱燐剤の吹き込み装置を二重に設ける必要があり、設備費用の大幅な増大が避けられない。 Furthermore, Patent Document 3 discloses removal of oxygen gas, iron oxide, CaO-based flux, etc. from two immersion lances inserted in the longitudinal direction of the mixing car into the hot metal charged in the mixing car. A method of hot metal dephosphorization is disclosed in which a phosphorous agent is blown with a carrier gas. According to this method, since the dephosphorizing agent can be dispersedly supplied to the molten metal compared to the method of dephosphorizing one immersion lance, dephosphorizing treatment can be performed at high speed while improving the reaction efficiency of the dephosphorizing agent. It is supposed to be possible to do. However, in order to blow in the dephosphorization agent from the two immersion lances, it is necessary to provide a double dephosphorization device for blowing in the dephosphorization agent, and a significant increase in equipment cost can not be avoided.
本発明は上記事情に鑑みてなされたもので、その目的とするところは、混銑車、溶銑鍋等の溶銑搬送容器に収容された溶銑を脱燐処理するにあたり、フッ素化合物を使用することなく生石灰等の安価なＣａＯ含有物質を媒溶剤として使用し、設備費用の大幅な増大を招くことなく溶銑の燐濃度を安定して低減できる溶銑の脱燐処理方法を提供することにある。 The present invention has been made in view of the above circumstances, and the object of the present invention is to prepare quick lime without using a fluorine compound when dephosphorizing hot metal contained in a hot metal transfer container such as a mixing wheel and hot metal pot. It is an object of the present invention to provide a hot metal dephosphorization treatment method which can stably reduce the phosphorus concentration of hot metal without using a cheap CaO-containing substance as a solvent and causing a large increase in equipment cost.
発明者らは、０．０１質量％程度といった低燐濃度までの脱燐処理に適した脱燐剤及び酸素の供給方法について鋭意検討した結果、特許文献３に記載されているような２本の浸漬ランスから脱燐剤の吹き込みを行う方法は、このような低燐濃度までの脱燐には必ずしも適したものではないことに着目した。即ち、２本の浸漬ランスから脱燐剤の吹き込みを行う方法では、１本の浸漬ランスから脱燐剤の吹き込みを行う場合に比べて、脱燐剤の総吹き込み速度が大きくなることから、０．０１質量％程度といった低燐濃度まで脱燐処理を行う際には、温度降下速度が増大して脱燐反応の停滞を招く場合があった。そこで、脱燐剤の供給速度を増大することなく撹拌力を増大させて脱燐反応を促進するために、低燐濃度域において気体酸素の吹き込みを利用する方法を着想して、本発明を完成するに至った。 The inventors of the present invention conducted intensive studies on a method of supplying a dephosphorizing agent and oxygen suitable for dephosphorizing treatment to a low phosphorus concentration such as about 0.01% by mass. It was noted that the method of blowing the dephosphorization agent from the immersion lance is not necessarily suitable for dephosphorization to such a low phosphorus concentration. That is, in the method in which the dephosphorization agent is injected from two immersion lances, the total injection speed of the dephosphorization agent is greater than in the case where the dephosphorization agent is injected from one immersion lance; When performing the dephosphorization treatment to a low phosphorus concentration of about 01% by mass, the temperature decrease rate may be increased to cause stagnation of the dephosphorization reaction. Therefore, in order to accelerate the dephosphorization reaction by increasing the stirring power without increasing the supply rate of the dephosphorization agent, the present invention was completed on the idea of utilizing the blowing of gaseous oxygen in the low phosphorus concentration range. It came to
上記課題を解決するための本発明の特徴は、以下の通りである。
（１）溶銑搬送容器に収容された溶銑にインジェクションランスを介して酸化剤及びＣａＯ含有物質を吹き込む溶銑の脱燐処理方法であって、脱燐処理中に燐濃度が０．０３質量％以下に低下した前記溶銑に、前記インジェクションランスを介して酸化剤及びＣａＯ含有物質を吹き込むとともに、前記インジェクションランスとは別に設けた気体酸素供給用ランスの気体酸素の出口を前記溶銑に浸漬させた状態で、前記気体酸素供給用ランスから気体酸素を前記溶銑に吹き込むことを特徴とする、溶銑の脱燐処理方法。
（２）前記気体酸素供給用ランスの気体酸素の出口を前記溶銑に浸漬させて前記気体酸素を前記溶銑中に吹き込む場合に、前記気体酸素の供給速度を前記溶銑１ｔ当たり０．０２Ｎｍ３／（ｍｉｎ・ｔ）以上０．１０Ｎｍ３／（ｍｉｎ・ｔ）以下にし、前記気体酸素供給用ランスの気体酸素の出口の浸漬深さを０．３ｍ以上にすることを特徴とする、（１）に記載の溶銑の脱燐処理方法。
（３）燐濃度が０．０３質量％超えの溶銑に、前記気体酸素供給用ランスの気体酸素の出口を前記溶銑の浴面よりも上に位置させて、前記気体酸素供給用ランスから前記気体酸素を前記溶銑に上吹きすることを特徴とする、（１）または（２）に記載の溶銑の脱燐処理方法。
（４）前記気体酸素供給用ランスの気体酸素の出口を前記浴面よりも上に位置させて前記気体酸素を前記溶銑に上吹きする場合に、前記気体酸素の供給速度を前記溶銑１ｔ当たり０．０５Ｎｍ３／（ｍｉｎ・ｔ）以上０．１０Ｎｍ３／（ｍｉｎ・ｔ）以下にし、前記気体酸素供給用ランスの気体酸素の出口の前記浴面からの高さを０．３ｍ以上０．７ｍ以下にすることを特徴とする、（３）に記載の溶銑の脱燐処理方法。
（５）前記脱燐処理後の前記溶銑の燐濃度を０．００８質量％以下にすることを特徴とする、（１）から（４）の何れか１つに記載の溶銑の脱燐処理方法。
The features of the present invention for solving the above problems are as follows.
(1) A method of dephosphorizing a molten metal in which an oxidizing agent and a CaO-containing substance are blown into a molten metal stored in a molten metal transport container through an injection lance, and the phosphorus concentration is 0.03 mass% or less during the dephosphorization processing While blowing the oxidizing agent and the CaO-containing substance through the injection lance into the lowered hot metal, and with the outlet for gaseous oxygen of the lance for supplying oxygen supplied separately from the injection lance dipped in the hot metal, A method for dephosphorizing molten iron, comprising: injecting gaseous oxygen into the molten iron from the lance for supplying gaseous oxygen.
(2) When the gaseous oxygen outlet for the gaseous oxygen supply lance is immersed in the molten iron and the gaseous oxygen is blown into the molten iron, the supply rate of the gaseous oxygen is 0.02 Nm 3 / (t) for the molten iron. min. t) or more and 0.10 Nm 3 / (min. t) or less, and the immersion depth of the outlet of the gaseous oxygen of the lance for gaseous oxygen supply is 0.3 m or more, (1) Dephosphorization treatment method of hot metal as described.
(3) In the molten metal having a phosphorus concentration of more than 0.03% by mass, the gaseous oxygen outlet of the gas oxygen supplying lance is located above the bath surface of the molten metal, and the gas from the gaseous oxygen supplying lance is (10) The method according to (1) or (2), wherein oxygen is blown up to the hot metal.
(4) When the outlet for gaseous oxygen of the lance for gaseous oxygen supply is positioned above the bath surface and the gaseous oxygen is blown upward to the molten iron, the supply rate of the gaseous oxygen is 0 per t of the molten iron. .05 Nm 3 / (min · t) or more and 0.10 Nm 3 / (min · t) or less, and the height from the bath surface of the outlet of the gaseous oxygen of the lance for gaseous oxygen supply is 0.3 m or more and 0.7 m The method for dephosphorizing molten metal according to (3), characterized in that:
(5) The method of dephosphorizing molten metal according to any one of (1) to (4), wherein the phosphorus concentration of the molten metal after the dephosphorizing treatment is 0.008 mass% or less. .
本発明による溶銑の脱燐処理方法を実施することで、脱燐設備の設備費用の増大を招くことなく、低燐濃度域における脱燐速度を向上でき、脱燐処理後の溶銑の燐濃度を安定して０．０１０質量％以下に低減できる。 By carrying out the dephosphorization treatment method of hot metal according to the present invention, the dephosphorization rate in the low phosphorus concentration region can be improved without increasing the equipment cost of the dephosphorization facility, and the phosphorus concentration of the hot metal after the dephosphorization treatment It can be stably reduced to 0.010% by mass or less.
溶銑搬送容器における溶銑の脱燐処理では、脱燐反応のための酸化剤として焼結鉱などの酸化鉄含有物質を用いることが一般的であり、インジェクションランスを介して酸化剤及びＣａＯ含有物質を吹き込む方法が広く用いられている。この際、吹き込まれた酸化剤の一部は、溶銑中を浮上中に溶銑中の炭素、珪素、燐及びマンガンなどと反応するが、短かい浮上時間中に十分に反応が進行する訳ではなく、溶銑上に浮かんでいるスラグ中にも大量の酸化鉄が供給され、スラグと溶銑との間でも酸化還元反応が一部進行する。 In the dephosphorization treatment of hot metal in a hot metal transport container, it is common to use an iron oxide-containing material such as sintered ore as an oxidizing agent for the dephosphorization reaction, and the oxidizing agent and CaO-containing material are injected through an injection lance. The blowing method is widely used. At this time, a part of the blown-in oxidant reacts with carbon, silicon, phosphorus, manganese, etc. in molten metal while floating in the molten metal, but the reaction does not necessarily proceed sufficiently during a short floating time. Also, a large amount of iron oxide is supplied also to the slag floating on the hot metal, and the redox reaction partially progresses also between the slag and the hot metal.
しかしながら、一般的にフリーボードの小さい溶銑搬送容器でのスラグと溶銑との撹拌は必ずしも十分ではなく、主に反応ガスの浮上領域付近で反応する以外は、脱燐反応への寄与は小さいと考えられていた。特に、混銑車（トピードカー）ではフリーボード及び開口部が小さく、開口部からの溶銑等の噴出を防止するために、斜め吹きのインジェクションランスを用いており、反応ガスを含む混相流の浮上位置が容器の長手方向に偏った位置となるので、容器内全体で見た場合にはスラグと溶銑との反応は活発ではないと考えられていた。 However, in general, stirring of slag and molten metal in a small freeboard small molten metal transfer container is not always sufficient, and the contribution to the dephosphorization reaction is considered to be small except for reaction mainly in the vicinity of the floating region of the reaction gas. It was being done. In particular, in a mixing car (topied car), the freeboard and the opening are small, and in order to prevent the spouting of molten iron etc. from the opening, an injection lance of oblique blowing is used, and the floating position of the multiphase flow containing the reaction gas is It was considered that the reaction between the slag and the molten metal was not active when viewed from the entire inside of the container because the container was biased in the longitudinal direction.
そこで、発明者らはスラグの有する脱燐能をさらに有効に利用する方法を種々検討し、インジェクションランスとは別に設けた気体酸素供給用ランスを介して、溶銑に浸漬させたノズルから気体酸素を溶銑中に吹き込むことで、溶銑中燐濃度が０．０３質量％以下の低燐濃度域における脱燐速度を向上できることを見出して本発明を完成させた。以下、発明の実施の形態を通じて本発明を説明する。 Therefore, the inventors examined various methods for more effectively utilizing the dephosphorization ability of the slag, and through the lance for gas oxygen supply provided separately from the injection lance, the gas oxygen was removed from the nozzle immersed in the hot metal By blowing into a molten metal, it was found that the dephosphorization rate in a low phosphorus concentration region where the phosphorus concentration in the molten metal is 0.03% by mass or less can be improved to complete the present invention. Hereinafter, the present invention will be described through embodiments of the invention.
図１は、本実施形態に係る溶銑の脱燐処理方法を用いて混銑車に収容された溶銑に脱燐処理を施す際に、低燐濃度域の溶銑に対して脱燐処理を施す場合の様子を示す概略図である。高炉から出銑された溶銑２０は、炉口１２を通って溶銑搬送容器（混銑車）１４に収容され、気体酸素供給ランス１６と、インジェクションランス１８とを備えた溶銑脱燐設備１０に移送され、脱燐処理が施される。また、溶銑搬送容器１４に収容された溶銑２０は、本実施形態に係る溶銑の脱燐処理方法による脱燐処理が実施された後に、製鋼用精錬炉（転炉）を備えた製鋼工場に搬送され、溶銑搬送容器１４を、回転軸を中心として傾斜させて、炉口１２から装入鍋（不図示）等の容器に出湯され、その後さらに脱硫処理及び脱炭処理が施される。 FIG. 1 shows the case where the molten metal stored in the mixing car is dephosphorized using the method for dephosphorizing molten metal according to the present embodiment, and the molten metal in the low phosphorus concentration region is dephosphorized. It is the schematic which shows a mode. The hot metal 20 discharged from the blast furnace is stored in a hot metal transfer container (mixing vehicle) 14 through a furnace port 12 and transferred to a hot metal dephosphorization facility 10 equipped with a gas oxygen supply lance 16 and an injection lance 18. And dephosphorization treatment. Moreover, the molten iron 20 accommodated in the molten metal conveyance container 14 is conveyed to a steelmaking factory provided with a steelmaking refining furnace (converter) after the dephosphorization treatment according to the present embodiment is performed. The molten metal transfer container 14 is inclined about the rotation axis and is poured from a furnace port 12 into a container such as a charging pot (not shown), and then desulfurization and decarburization are further applied.
以下に、溶銑脱燐設備１０における各装置の構成について説明する。インジェクションランス１８は、炉口１２から鉛直方向に対して斜めに混銑車に挿入され、溶銑２０に浸漬された状態で保持され、インジェクションランス１８から酸化剤である酸化鉄と、ＣａＯ含有物質とを含む脱燐剤３４を、搬送ガス３６とともに溶銑２０へ吹き込む。インジェクションランス１８から吹き込まれる酸化剤としては、鉄鉱石、鉄鉱石の焼結鉱粉、ミルスケール等の酸化鉄源を使用することができ、また、気体酸素をこれらの酸化鉄源とともに酸化剤として併用できる。また、インジェクションランス１８で使用する搬送ガス３６としては、気体酸素、空気、窒素ガス、希ガスなどを使用することができる。 Below, the structure of each apparatus in the hot metal dephosphorization installation 10 is demonstrated. The injection lance 18 is inserted into the mixing car obliquely from the hearth opening 12 with respect to the vertical direction, held in a state immersed in the hot metal 20, and from the injection lance 18 iron oxide which is an oxidant and a CaO containing substance The dephosphorization agent 34 is blown into the hot metal 20 together with the carrier gas 36. As the oxidizing agent blown from the injection lance 18, iron oxide sources such as iron ore, sintered ore powder of iron ore, mill scale, etc. can be used, and gaseous oxygen is used as an oxidizing agent together with these iron oxide sources. It can be used together. Further, as the carrier gas 36 used in the injection lance 18, gaseous oxygen, air, nitrogen gas, a rare gas or the like can be used.
インジェクションランス１８の外側には不定形耐火物からなる耐火物被覆層が設けられており、内部は単管または２重管構造となっている。インジェクションランス１８が２重管構造となっている場合は、内管と外管との隙間からは例えばインジェクションランス１８を保護するための冷却用流体が供給される。 On the outside of the injection lance 18, a refractory covering layer made of a monolithic refractory is provided, and the inside is a single pipe or double pipe structure. When the injection lance 18 has a double-pipe structure, a cooling fluid for protecting, for example, the injection lance 18 is supplied from the gap between the inner pipe and the outer pipe.
気体酸素供給ランス１６は、炉口１２から鉛直方向に溶銑搬送容器１４の内部に挿入される。気体酸素２２は、気体酸素供給ランス１６から溶銑２０に供給される。気体酸素供給ランス１６は、図１に示すように、気体酸素供給ランス１６の気体酸素の出口が溶銑搬送容器１４内の溶銑２０に浸漬された状態で保持されるように構成され、気体酸素供給ランス１６から気体酸素２２を溶銑２０に吹き込むことができる。 The gaseous oxygen supply lance 16 is inserted into the interior of the hot metal carrier 14 in the vertical direction from the furnace port 12. The gaseous oxygen 22 is supplied to the hot metal 20 from the gaseous oxygen supply lance 16. The gaseous oxygen supply lance 16 is configured such that the gaseous oxygen outlet of the gaseous oxygen supply lance 16 is held in the molten metal 20 in the molten metal transport container 14 as shown in FIG. Gaseous oxygen 22 can be blown into the hot metal 20 from the lance 16.
また、図２は、本実施形態に係る溶銑の脱燐処理方法を用いて混銑車に収容された溶銑に脱燐処理を施す際に、後述する高燐濃度域の溶銑に対して脱燐処理を施す場合の様子を示す概略図である。図２に示すように、気体酸素供給ランス１６の気体酸素の出口が溶銑２０の浴面よりも上の位置でも保持できるように構成され、気体酸素供給ランス１６から気体酸素２２を溶銑２０に上吹きできることが好ましい。 Further, FIG. 2 shows that when the hot metal contained in the mixing car is subjected to the dephosphorization treatment using the hot metal dephosphorization treatment method according to the present embodiment, the hot metal in the high phosphorus concentration region described later It is the schematic which shows the mode in the case of giving. As shown in FIG. 2, the gaseous oxygen supply lance 16 is configured such that the gaseous oxygen outlet can be held at a position above the bath surface of the molten iron 20, and the gaseous oxygen supply lance 16 places the gaseous oxygen 22 on the molten iron 20. It is preferable to be able to blow.
図３は、気体酸素供給ランス１６の断面図である。図３を用いて、気体酸素供給ランス１６の構造を説明する。気体酸素供給ランス１６は、内管２４及び外管２６を有する二重管構造となっており、外管２６の外側には、不定形耐火物から構成される耐火物被覆層２８が設けられている。内管２４は、気体酸素供給ランス１６の下部で、図３における左右の２方向に分岐し、気体酸素の出口である左右２つの内管ノズル３０に接続している。また、外管２６も内管２４と同じく、気体酸素供給ランス１６の下部で左右の２方向に分岐し、外管２６と内管２４との隙間も、左右２つの外管ノズル３２に接続している。なお、図３における左右方向を混銑車の長手方向に一致させるように気体酸素供給ランス１６を設置することが好ましい。 FIG. 3 is a cross-sectional view of the gaseous oxygen lance 16. The structure of the gaseous oxygen supply lance 16 will be described with reference to FIG. The gaseous oxygen supply lance 16 has a double tube structure having an inner tube 24 and an outer tube 26, and a refractory covering layer 28 composed of a monolithic refractory is provided on the outside of the outer tube 26. There is. The inner pipe 24 branches in two directions, left and right in FIG. 3, at the lower part of the gas oxygen supply lance 16 and is connected to the two inner pipe nozzles 30 on the left and right which are outlets of the gaseous oxygen. Also, the outer pipe 26 is branched to the left and right in two directions at the lower part of the gas oxygen supply lance 16 similarly to the inner pipe 24 and the gap between the outer pipe 26 and the inner pipe 24 is also connected to the two outer pipe nozzles 32 on the left and right ing. Preferably, the gas oxygen supply lance 16 is installed so that the left and right direction in FIG. 3 coincides with the longitudinal direction of the mixing vehicle.
気体酸素供給ランス１６の内管２４からは、気体酸素２２が供給され、内管２４と外管２６との隙間からは、気体酸素２２の反応熱から内管ノズル３０を保護するための冷却用の流体が供給される。気体酸素供給ランス１６の内管ノズル３０を溶銑２０に浸漬して気体酸素２２を吹き込む場合には、冷却用の流体として炭化水素ガス、または、搬送ガスによって搬送される液体炭化水素などを用いる。これにより、気体酸素供給ランス１６の耐用性を向上できる。また、気体酸素供給ランス１６の内管ノズル３０を溶銑２０の浴面より上にして気体酸素２２を上吹きする場合には、冷却用の流体として窒素、または、不活性ガス等の気体を用いてよい。 Gaseous oxygen 22 is supplied from the inner pipe 24 of the gas oxygen supply lance 16, and the gap between the inner pipe 24 and the outer pipe 26 is a cooling for protecting the inner pipe nozzle 30 from the heat of reaction of the gaseous oxygen 22. Fluid is supplied. In the case where the inner pipe nozzle 30 of the gas oxygen supply lance 16 is immersed in the hot metal 20 and the gas oxygen 22 is blown, a hydrocarbon gas or liquid hydrocarbon carried by a carrier gas is used as a cooling fluid. Thereby, the durability of the gaseous oxygen supply lance 16 can be improved. When the gas oxygen 22 is blown up with the inner pipe nozzle 30 of the gas oxygen supply lance 16 above the bath surface of the molten iron 20, a gas such as nitrogen or an inert gas is used as the cooling fluid. You may
内管ノズル３０は、図３に示すように、例えば、鉛直下向き方向に対して４５°となる左右２方向に分岐して設けられる。このように、内管ノズル３０を互いに異なる方向に設け、内管２４を分岐させることで、気体酸素供給ランス１６から互いに異なる方向に分散して気体酸素２２を噴出できる。なお、内管ノズル３０の方向は、鉛直下向き方向に対して３０°以上６０°以下にすることが好ましい。内管ノズル３０の方向を鉛直下向き方向に対して３０°以上にすることで、内管ノズル３０を溶銑２０に浸漬して気体酸素２２を吹き込む場合には、気泡の水平方向の到達距離を大きくしてスラグ／メタルの撹拌領域を拡大できる。また、内管ノズル３０を溶銑２０の浴面より上にして気体酸素２２を上吹きする場合には、内管ノズル３０の方向を鉛直下向き方向に対して３０°以上にすることで、酸化鉄の溶銑２０への吹き込みによって発生したＣＯガスの二次燃焼を促進させることができ、溶銑２０及びスラグ３８への着熱量を増やすことができる。 As shown in FIG. 3, for example, the inner pipe nozzle 30 is branched in two directions, left and right, which are 45 ° with respect to the vertically downward direction. As described above, by providing the inner pipe nozzles 30 in mutually different directions and branching the inner pipe 24, it is possible to disperse gas oxygen from the gas oxygen supply lance 16 in mutually different directions. The direction of the inner pipe nozzle 30 is preferably 30 ° or more and 60 ° or less with respect to the vertically downward direction. When immersing the inner tube nozzle 30 in the hot metal 20 and blowing in the gaseous oxygen 22 by setting the direction of the inner tube nozzle 30 to 30 ° or more with respect to the vertical downward direction, the horizontal distance of the bubbles is increased. Thus, the slag / metal stirring area can be expanded. Further, in the case where the inner tube nozzle 30 is above the bath surface of the hot metal 20 and the gas oxygen 22 is blown upward, the direction of the inner tube nozzle 30 is set to 30 ° or more with respect to the vertical downward direction. The secondary combustion of CO gas generated by the blowing into the hot metal 20 can be promoted, and the heat generation amount to the hot metal 20 and the slag 38 can be increased.
また、内管ノズル３０の方向を鉛直下向き方向に対して６０°以下にすることで、溶銑２０に気体酸素２２を上吹きする場合に、溶銑搬送容器１４の内壁、特に天井部分の耐火物がＣＯガスの二次燃焼による高温に曝されて耐火物の溶損が増大することを抑制できるとともに、当該二次燃焼熱を効率良く溶銑２０及びスラグ３８に伝熱できる。 In addition, when the gas oxygen 22 is blown upward to the hot metal 20 by setting the direction of the inner pipe nozzle 30 to 60 ° or less with respect to the vertical downward direction, the refractory of the inner wall of the hot metal transfer container 14, particularly the ceiling portion While being able to suppress that it is exposed to the high temperature by the secondary combustion of CO gas, and the melting loss of a refractory material increasing, the said secondary combustion heat can be efficiently transferred to the hot metal 20 and the slag 38 efficiently.
以下に、溶銑脱燐設備１０を用いる本発明に係る溶銑の脱燐処理方法の実施形態について説明する。インジェクションランス１８から供給される酸化鉄及び気体酸素からなる酸化剤中の酸素により、溶銑中の燐が酸化されて燐酸化物が生成する酸化反応（２Ｐ＋５／２Ｏ２→Ｐ２Ｏ５）が起こる。この燐酸化物が、添加されるＣａＯ含有物質の滓化によって形成されるスラグ３８に吸収されることで溶銑２０の脱燐が進行する。脱燐処理においては、スラグからの復燐反応を抑制するとともに、スラグの液相率が著しく低下して撹拌・混合が阻害されることを防止する観点から、脱燐処理後のスラグの塩基度が１．５以上３．０以下になるように、脱燐剤３４の吹き込み量を調整することが好ましい。 Hereinafter, an embodiment of a hot metal dephosphorization treatment method according to the present invention using the hot metal dephosphorization facility 10 will be described. The oxidation reaction (2P + 5 / 2O 2 → P 2 O 5 ) occurs in which the phosphorus in the hot metal is oxidized by the oxygen in the oxidant consisting of iron oxide and gaseous oxygen supplied from the injection lance 18 to oxidize the phosphorus in the hot metal. The phosphorus oxide is absorbed by the slag 38 formed by the hydrogenation of the CaO-containing substance to be added, whereby the dephosphorization of the hot metal 20 proceeds. In the dephosphorization treatment, the basicity of the slag after the dephosphorization treatment from the viewpoint of suppressing the rephosphorization reaction from the slag and preventing the liquid phase rate of the slag from being significantly reduced to thereby inhibit the stirring and mixing. It is preferable to adjust the blowing amount of the dephosphorization agent 34 so as to be 1.5 or more and 3.0 or less.
図４は、従来の混銑車での溶銑脱燐処理における脱珪外酸素原単位と、脱燐処理後の溶銑の燐濃度との関係を示したグラフである。図４に示したグラフにおいて、横軸は、脱珪外酸素原単位（Ｎｍ３／ｔ）であり、縦軸は、脱燐処理後の溶銑の燐濃度である。なお、脱珪外酸素原単位とは、炉内に供給される酸素原単位のうち、脱珪反応に使用される分を除いた酸素原単位を意味する。図４に示すように、溶銑の燐濃度０．０３質量％を境界にグラフの傾きが徐々に小さくなっている。このことから、溶銑の燐濃度が０．０３質量％超えの高燐濃度域では脱燐酸素効率の変化は小さく、燐濃度が０．０３質量％以下の低燐濃度域では、溶銑中における燐の物質移動速度の影響で、燐濃度が低下するに従って脱燐酸素効率が低下すると考えられる。従来のフッ素化合物を使用しない溶銑の脱燐処理方法では、低燐濃度域で脱燐酸素効率が低下するため、脱燐剤原単位の増大と処理時間の延長が必要となり、これにより溶銑温度が低下することでさらに脱燐反応の停滞を招き、低燐溶銑の製造を難しくしていた。 FIG. 4 is a graph showing the relationship between the desilicateing oxygen unit in the hot metal dephosphorizing treatment of a conventional mixing car and the phosphorus concentration of the hot metal after the dephosphorizing treatment. In the graph shown in FIG. 4, the horizontal axis is the desiliconizing extraneous oxygen unit (Nm 3 / t), and the vertical axis is the phosphorus concentration of the molten metal after the dephosphorization treatment. In addition, the silicon | silicone removal outside silicon unit means the oxygen basic unit except the part used for a silicon removal reaction among the oxygen units which are supplied in a furnace. As shown in FIG. 4, the slope of the graph gradually decreases at the boundary of the phosphorus concentration of 0.03% by mass of hot metal. From this, the change in dephosphorization oxygen efficiency is small in the high phosphorus concentration region where the phosphorus concentration of the molten metal exceeds 0.03 mass%, and in the low phosphorus concentration region where the phosphorus concentration is 0.03 mass% or less, the phosphorus in the molten metal It is believed that the dephosphorization oxygen efficiency decreases as the phosphorus concentration decreases due to the mass transfer rate of In the conventional method of dephosphorizing hot metal without using a fluorine compound, the dephosphorization oxygen efficiency is lowered in the low phosphorus concentration region, so it is necessary to increase the dephosphorizing agent base unit and extend the processing time, which causes the hot metal temperature The decrease further causes stagnation of the dephosphorization reaction, making it difficult to produce a low phosphorus solution.
本実施形態に係る溶銑の脱燐処理方法において、溶銑２０の燐濃度が０．０３質量％以下の溶銑中における燐の物質移動速度の影響で脱燐酸素効率が低下する領域では、図１に示したように、内管ノズル３０が溶銑２０に浸漬した状態で気体酸素供給ランス１６を保持し、当該気体酸素供給ランス１６から溶銑２０に気体酸素２２を吹き込み、気体酸素２２の吹き込みによって生成されたＣＯガスによって溶銑搬送容器１４内の溶銑２０を撹拌する。これにより、溶銑２０中の燐の物質移動が促進されて、インジェクションランス１８から吹き込む脱燐剤３４による脱燐反応を促進できる。さらに、気体酸素供給ランス１６から溶銑２０に気体酸素２２を吹き込み、気体酸素２２の吹き込みによって生成されたＣＯガスによって溶銑搬送容器１４内のスラグ３８と溶銑２０との撹拌・混合も促進される。これにより、スラグ３８による脱燐反応も促進できる。このように、溶銑２０に気体酸素２２を吹き込むことで、溶銑２０中における物質移動を促進して脱燐剤３４による脱燐反応を促進できるとともにスラグ３８による脱燐反応をも促進でき、この結果、溶銑２０の脱燐速度は向上し、溶銑２０の燐濃度を安定して０．０１０質量％以下に低減できる。 In the region where the dephosphorization oxygen efficiency decreases due to the effect of the mass transfer rate of phosphorus in the molten metal with a phosphorus concentration of 0.03% by mass or less in the molten metal dephosphorization treatment method according to the present embodiment, FIG. As shown, with the inner tube nozzle 30 immersed in the molten iron 20, the gaseous oxygen supply lance 16 is held, and the gaseous oxygen supply lance 16 blows the gaseous oxygen 22 into the molten iron 20 and is generated by the gaseous oxygen 22 The hot metal 20 in the hot metal transfer container 14 is stirred by the CO gas. Thereby, the mass transfer of phosphorus in the hot metal 20 is promoted, and the dephosphorization reaction by the dephosphorization agent 34 blown from the injection lance 18 can be promoted. Furthermore, the gaseous oxygen 22 is blown into the molten metal 20 from the gaseous oxygen supply lance 16, and the CO gas generated by the gaseous oxygen 22 promotes stirring and mixing of the slag 38 and the molten metal 20 in the molten metal transport container 14. Thereby, the dephosphorization reaction by the slag 38 can also be promoted. Thus, by blowing gaseous oxygen 22 into the hot metal 20, it is possible to promote mass transfer in the hot metal 20 to promote the dephosphorization reaction by the dephosphorization agent 34 and also to promote the dephosphorization reaction by the slag 38. The dephosphorization rate of the hot metal 20 is improved, and the phosphorus concentration of the hot metal 20 can be stably reduced to 0.010 mass% or less.
また、溶銑２０の燐濃度が０．０３質量％超えの脱燐酸素効率の変化が小さい高燐濃度域では、溶銑２０に気体酸素２２を吹き込んでも脱燐反応の促進効果は大きくないため、図２に示したように、内管ノズル３０が溶銑２０の浴面よりも上になる位置で気体酸素供給ランス１６を保持し、溶銑２０に気体酸素２２を上吹きすることが好ましい。このように、溶銑２０に気体酸素２２を上吹きすることによって、脱燐処理中に過剰に脱炭が進んで、次工程の熱源として使用できる溶銑中の炭素が減少することを抑制できる。さらに、溶銑２０の浴面に気体酸素２２を上吹きすることで、酸化鉄の吹き込みによって発生したＣＯガスを効果的に二次燃焼させることができ、溶銑２０及びスラグ３８への着熱量を増やすことができる。 Also, in the high phosphorus concentration area where the phosphorus concentration of the hot metal 20 is more than 0.03% by mass and the change in the dephosphorization oxygen efficiency is small, blowing the gaseous oxygen 22 into the hot metal 20 does not have a large promoting effect on the dephosphorization reaction. As shown in FIG. 2, it is preferable to hold the gaseous oxygen supply lance 16 at a position where the inner pipe nozzle 30 is above the bath surface of the hot metal 20, and to blow the hot oxygen 20 to the hot metal 20. As described above, by blowing the gaseous oxygen 22 upward to the hot metal 20, it is possible to suppress excessive reduction of carbon in the hot metal that can be used as a heat source of the next step due to excessive decarbonization during the dephosphorization treatment. Furthermore, by blowing gas oxygen 22 upward to the bath surface of the hot metal 20, the CO gas generated by the blowing of iron oxide can be effectively secondarily burned, and the heat generation amount to the hot metal 20 and the slag 38 is increased. be able to.
脱燐処理中の溶銑２０の燐濃度は、高炉から出銑した溶銑２０の燐濃度の測定値と、インジェクションランス１８から吹き込む酸化鉄と気体酸素からなる酸化剤の供給量と、経験的に得られている各酸化剤の脱燐酸素効率とから推定できる。すなわち、溶銑２０の燐濃度が０．０３質量％となる酸化剤あるいは脱燐剤３４を供給した時点の近辺で、気体酸素供給ランス１６の高さを変更すればよい。 The phosphorus concentration of the hot metal 20 during the dephosphorization treatment is obtained empirically from the measured value of the phosphorus concentration of the hot metal 20 discharged from the blast furnace and the supply amount of the oxidizing agent consisting of iron oxide and gaseous oxygen blown from the injection lance 18 It can be estimated from the dephosphorization oxygen efficiency of each oxidizing agent. That is, the height of the gas oxygen supply lance 16 may be changed in the vicinity of the point of supplying the oxidizing agent or the dephosphorizing agent 34 in which the phosphorus concentration of the hot metal 20 is 0.03 mass%.
また、溶銑２０の燐濃度が０．０３質量％以下であって、気体酸素供給ランス１６から溶銑２０に気体酸素２２を吹き込む場合において、気体酸素供給ランス１６の内管ノズル３０の先端を溶銑２０の浴面から０．３ｍ以上浸漬させることが好ましく、さらに、０．５ｍ以上浸漬させることがより好ましい。また、溶銑２０に気体酸素２２を吹き込む場合に、気体酸素供給ランス１６から供給する気体酸素２２の供給速度を０．０２Ｎｍ３／（ｍｉｎ・ｔ）以上にすることが好ましく、さらに、０．０５Ｎｍ３／（ｍｉｎ・ｔ）以上にすることがより好ましい。このように、気体酸素供給ランス１６の内管ノズル３０の浸漬深さ、及び／または、気体酸素２２の供給速度を上記の範囲内にすることで撹拌動力密度が高くなり、これにより、溶銑２０中の脱燐を効果的に促進できる。一方、気体酸素２２の供給速度を大きくし過ぎても、脱燐速度の向上効果は飽和し、かえって脱炭量の増大を招くので、気体酸素２２の供給速度は０．１０Ｎｍ３／（ｍｉｎ・ｔ）以下にすることが好ましい。 In the case where the phosphorus concentration of the molten iron 20 is 0.03 mass% or less and the gaseous oxygen 22 is blown into the molten iron 20 from the gaseous oxygen supply lance 16, the tip of the inner pipe nozzle 30 of the gaseous oxygen supply lance 16 is It is preferable to immerse 0.3 m or more from the bath surface, and it is more preferable to immerse 0.5 m or more. Moreover, when blowing gaseous oxygen 22 into the hot metal 20, it is preferable to set the supply rate of the gaseous oxygen 22 supplied from the gaseous oxygen supply lance 16 to 0.02 Nm 3 / (min · t) or more, and more preferably 0.05 Nm. It is more preferable to set it to 3 / (min · t) or more. As described above, by setting the immersion depth of the inner tube nozzle 30 of the gas oxygen supply lance 16 and / or the supply rate of the gas oxygen 22 within the above range, the stirring power density is increased. It can effectively promote the dephosphorization inside. On the other hand, even if the supply rate of gaseous oxygen 22 is increased too much, the improvement effect of the dephosphorization rate saturates, which in turn causes an increase in the amount of decarburization, so the supply rate of gaseous oxygen 22 is 0.10 Nm 3 / (min · · t) or less is preferable.
さらに、溶銑２０の燐濃度が０．０３質量％超えであって、気体酸素供給ランス１６から溶銑２０に気体酸素２２を上吹きする場合において、気体酸素供給ランス１６の内管ノズル３０の先端の溶銑２０の浴面からの高さを０．３ｍ以上、０．７ｍ以下にすることが好ましく、さらに、０．３ｍ以上、０．５ｍ以下にすることがより好ましい。また、溶銑２０に気体酸素２２を上吹きする場合に、気体酸素供給ランス１６から供給する気体酸素２２の供給速度を０．０５Ｎｍ３／（ｍｉｎ・ｔ）以上にすることが好ましい。このように、気体酸素供給ランス１６の内管ノズル３０の溶銑浴面からの高さ、及び／または、気体酸素２２の供給速度を上記の範囲内にすることで二次燃焼量及び着熱効率を適正な範囲とすることができ、溶銑２０及びスラグ３８への着熱量を増やすことができる。一方、気体酸素２２の供給速度を大きくし過ぎると耐火物の溶損を増大させるおそれがあるので、気体酸素２２の供給速度は０．１０Ｎｍ３／（ｍｉｎ・ｔ）以下にすることが好ましい。 Furthermore, when the phosphorus concentration of the hot metal 20 exceeds 0.03 mass% and the gas oxygen 22 is blown up from the gas oxygen supply lance 16 to the hot metal 20, the tip of the inner pipe nozzle 30 of the gas oxygen supply lance 16 The height of the hot metal 20 from the bath surface is preferably 0.3 m or more and 0.7 m or less, and more preferably 0.3 m or more and 0.5 m or less. Further, in the case where the gaseous oxygen 22 is blown upward to the hot metal 20, the supply rate of the gaseous oxygen 22 supplied from the gaseous oxygen supply lance 16 is preferably set to 0.05 Nm 3 / (min · t) or more. Thus, by setting the height from the hot metal bath surface of the inner tube nozzle 30 of the gaseous oxygen supply lance 16 and / or the supply rate of the gaseous oxygen 22 within the above range, the secondary combustion amount and heat transfer efficiency can be achieved. The appropriate range can be made, and the heat amount to the hot metal 20 and the slag 38 can be increased. On the other hand, if the supply rate of the gaseous oxygen 22 is excessively increased, there is a possibility that melting loss of the refractory may be increased. Therefore, the supply rate of the gaseous oxygen 22 is preferably 0.10 Nm 3 / (min · t) or less.
また、本実施形態に係る溶銑の脱燐処理方法は、滓化促進剤としてフッ素化合物を使用せずに、生石灰等の安価なＣａＯ含有物質を使用することが望ましい。これにより、当該脱燐処理方法の実施により生じるスラグはフッ素化合物を含まないので、炉盤材等の土木工事材料としての利用が制限されず、スラグの処理コストの増加に伴う製造コストの上昇を抑制できる。 Moreover, as for the dephosphorization processing method of the hot metal which concerns on this embodiment, it is desirable to use cheap CaO containing materials, such as quick lime, without using a fluorine compound as a hardening promotion agent. As a result, since the slag generated by the implementation of the dephosphorization treatment method does not contain a fluorine compound, the use as a civil engineering material such as a blast furnace material and the like is not limited, and the manufacturing cost increases due to an increase in the processing cost of slag. It can be suppressed.
また、溶銑２０への気体酸素２２の上吹きと、溶銑２０への気体酸素２２の吹き込みとを別々のランスを用いて行なうとなると、設備費用の増大、オペレーションの複雑化、ランス変更時の酸素供給時間のロス等の問題が発生する。これに対し、本発明の一つの実施形態に係る溶銑の脱燐処理方法では、１本の気体酸素供給ランス１６を用いて、溶銑２０の浴面への気体酸素２２の上吹きと、溶銑２０への気体酸素２２の吹き込みとを実施できるので、設備費用を増大させること、オペレーションを複雑化させること、及び、ランス変更時の酸素供給時間のロスが発生することを抑制できる。 In addition, if the blowing of the gaseous oxygen 22 into the hot metal 20 and the blowing of the gaseous oxygen 22 into the hot metal 20 are performed using separate lances, the equipment cost increases, the operation becomes complicated, and the oxygen at the lance change. Problems such as loss of supply time occur. On the other hand, in the method of dephosphorizing hot metal according to one embodiment of the present invention, using one gas oxygen supply lance 16, the upper blowing of the gaseous oxygen 22 onto the bath surface of the hot metal 20 and the hot metal 20. Since the injection of the gaseous oxygen 22 can be performed, it is possible to increase the equipment cost, to complicate the operation, and to suppress the loss of the oxygen supply time at the time of the lance change.
また、上述した説明においては、混銑車用の溶銑脱燐設備１０を用いて本実施形態に係る溶銑の脱燐処理方法を実施した例を示したが、気体酸素供給ランス１６及びインジェクションランス１８を備えるものであれば、溶銑鍋であっても上述した説明に沿って本実施形態に係る溶銑の脱燐処理方法を実施できる。 In the above description, an example is shown in which the hot metal dephosphorization method according to the present embodiment is carried out using the hot metal dephosphorization facility 10 for a mixed car, but the gas oxygen supply lance 16 and the injection lance 18 If it is provided, even if it is a hot metal ladle, the dephosphorization treatment method of hot metal according to the present embodiment can be performed according to the above description.
容量約３００トンの混銑車に高炉から出銑した溶銑を受銑し、この溶銑に対して、脱燐剤としてフッ素化合物を使用せずに、溶銑の燐濃度を０．００８質量％以下にすることを目標に溶銑の脱燐処理を実施した。比較例１〜３は、インジェクションランス１８から焼結鉱粉と生石灰粉からなる脱燐剤３４を溶銑２０へ吹き込んで溶銑の脱燐処理を行い、脱燐処理全体を通じて、気体酸素供給ランス１６の内管ノズル３０の先端を溶銑の浴面からの高さを０．３０〜０.４５ｍにした位置から溶銑に気体酸素（工業用純酸素）を上吹きして脱燐処理を実施した。一方、実施例１〜３は、インジェクションランス１８から焼結鉱粉と生石灰粉からなる脱燐剤３４を溶銑２０へ吹き込んで溶銑の脱燐処理を行い、脱燐処理前半（溶銑の燐濃度０．０３質量％超え）においては、気体酸素供給ランス１６の内管ノズル３０の先端を溶銑の浴面からの高さを０．３０〜０.４５ｍにした位置から溶銑に気体酸素を上吹きして脱燐処理し、脱燐処理後半（溶銑の燐濃度０．０３質量％以下）においては、気体酸素供給ランス１６の内管ノズル３０の先端を溶銑の浴面から０．３０〜０．４５ｍ浸漬させた状態で、溶銑に気体酸素を吹き込んで脱燐処理した。生石灰の使用量は何れの実施例及び比較例においても溶銑１ｔ当たり約５ｋｇ／ｔとした。これらの処理条件及び結果を表１に示す。 A hot metal from the blast furnace is received in a mixing car with a capacity of about 300 tons, and the phosphorus concentration of the hot metal is reduced to 0.008 mass% or less without using a fluorine compound as a dephosphorizing agent for this hot metal. We performed dephosphorization treatment of hot metal with the goal of In Comparative Examples 1 to 3, the dephosphorizing agent 34 consisting of sintered mineral powder and quicklime powder is blown into the molten metal 20 from the injection lance 18 to perform dephosphorization processing of the molten metal, and the gas oxygen supply lance 16 is Degassing treatment was carried out by blowing gas oxygen (pure oxygen for industry) over the hot metal from a position where the height of the tip of the inner tube nozzle 30 from the bath surface of the hot metal was 0.30 to 0.45 m. On the other hand, in Examples 1 to 3, the dephosphorizing treatment of the molten metal is performed by blowing the dephosphorizing agent 34 consisting of sintered mineral powder and quicklime powder into the molten metal 20 from the injection lance 18 to remove phosphorus in the first half of the dephosphorizing treatment (phosphorus concentration of the molten metal 0 In the case where the height of the tip of the inner tube nozzle 30 of the gaseous oxygen supply lance 16 is 0.30 to 0.45 m, the gaseous oxygen is blown upward to the molten Dephosphorization treatment, and in the second half of the dephosphorization treatment (phosphorus concentration of 0.03% by mass or less of hot metal), the tip of the inner pipe nozzle 30 of the gas oxygen supply lance 16 is 0.30 to 0.45 m from the bath surface of the hot metal In the immersed state, gaseous oxygen was blown into the hot metal to remove phosphorus. The amount of quick lime used was about 5 kg / t per ton of molten iron in all the Examples and Comparative Examples. These processing conditions and results are shown in Table 1.
表１に示すように、脱燐処理全体を通じて気体酸素を浴面から０．３０〜０.４５ｍ上方位置から上吹きして脱燐処理した比較例１〜３においては、実施例１〜３と供給した気体酸素原単位が同じであるにも関わらず、脱燐処理後の溶銑の燐濃度を目標値である０．００８質量％以下にできなかった。さらに、比較例１では、脱燐処理後の溶銑の燐濃度が０．０１１質量％になっており、脱燐脱燐処理後の溶銑の燐濃度を安定して０．０１０質量％以下に低減できなかった。一方、実施例１〜３は、何れにおいても脱燐処理後の溶銑の燐濃度を目標値である０．００８質量％以下にすることができた。このように、本実施形態に係る溶銑の脱燐処理方法を実施することで、脱燐処理後の溶銑の燐濃度を安定して０．０１０質量％以下に低減できることが確認された。 As shown in Table 1, in Comparative Examples 1 to 3 in which dephosphorization was performed by blowing gas oxygen upward from the position 0.30 to 0.45 m above the bath surface throughout the dephosphorization treatment, Even though the supplied gaseous oxygen basic unit was the same, the phosphorus concentration of the hot metal after the dephosphorization treatment could not be reduced to the target value of 0.008 mass% or less. Furthermore, in Comparative Example 1, the phosphorus concentration of the molten metal after the dephosphorization treatment is 0.011 mass%, and the phosphorus concentration of the molten metal after the dephosphorization treatment is stably reduced to 0.010 mass% or less could not. On the other hand, in any of Examples 1 to 3, the phosphorus concentration of the molten metal after the dephosphorization treatment could be set to the target value of 0.008 mass% or less. As described above, it was confirmed that the phosphorus concentration of the molten metal after the dephosphorization treatment can be stably reduced to 0.010% by mass or less by carrying out the method for dephosphorizing the molten metal according to the present embodiment.
１０ 溶銑脱燐設備
１２ 炉口
１４ 溶銑搬送容器（混銑車）
１６ 気体酸素供給ランス
１８ インジェクションランス
２０ 溶銑
２２ 気体酸素
２４ 内管
２６ 外管
２８ 耐火物被覆層
３０ 内管ノズル
３２ 外管ノズル
３４ 脱燐剤
３６ 搬送ガス
３８ スラグ
10 hot metal dephosphorization equipment 12 furnace port 14 hot metal transfer container (mixing car)
DESCRIPTION OF SYMBOLS 16 Gas oxygen supply lance 18 Injection lance 20 Hot metal 22 Gas oxygen 24 Inner pipe 26 Outer pipe 28 Refractory coat layer 30 Inner pipe nozzle 32 Outer pipe nozzle 34 Dephosphorization agent 36 Carrier gas 38 Slag
Claims (4)
燐濃度が０．０３質量％超えの前記溶銑に、前記インジェクションランスを介して酸化剤及びＣａＯ含有物質を吹き込むとともに、前記インジェクションランスとは別に設けた気体酸素供給用ランスの気体酸素の出口を前記溶銑の浴面よりも上に位置させて、前記気体酸素供給用ランスから前記気体酸素を前記溶銑に上吹きし、
脱燐処理中に燐濃度が０．０３質量％以下に低下した前記溶銑に、前記インジェクションランスを介して酸化剤及びＣａＯ含有物質を吹き込むとともに、前記気体酸素供給用ランスの気体酸素の出口を前記溶銑に浸漬させた状態で、前記気体酸素供給用ランスから気体酸素を前記溶銑に吹き込むことを特徴とする、溶銑の脱燐処理方法。 A method of dephosphorizing a molten metal in which an oxidizing agent and a CaO-containing substance are blown through an injection lance into a molten metal stored in a molten metal transport container,
An oxidant and a CaO-containing substance are blown into the hot metal having a phosphorus concentration of more than 0.03% by mass through the injection lance, and the outlet for gaseous oxygen of the lance for supplying gaseous oxygen separately provided from the injection lance is Above the bath surface of the molten iron, the gaseous oxygen is blown up to the molten iron from the lance for supplying gaseous oxygen;
The hot metal to phosphorus concentrations in the dephosphorization drops below 0.03 wt%, with blowing an oxidizing agent and CaO-containing material through the injection lance, the outlet of the gaseous oxygen supply lance GOX A method of dephosphorizing treatment of molten metal, characterized in that gaseous oxygen is blown into the molten metal from the lance for supplying gaseous oxygen while immersed in the molten metal.
酸素を前記溶銑に上吹きする場合に、前記気体酸素の供給速度を前記溶銑１ｔ当たり０．０５Ｎｍ３／（ｍｉｎ・ｔ）以上０．１０Ｎｍ３／（ｍｉｎ・ｔ）以下にし、前記気体酸素供給用ランスの気体酸素の出口の前記浴面からの高さを０．３ｍ以上０．７ｍ以下にすることを特徴とする、請求項１または請求項２に記載の溶銑の脱燐処理方法。 When the gas oxygen outlet of the gas oxygen supply lance is positioned above the bath surface and the gas oxygen is blown upward to the molten iron, the supply rate of the gaseous oxygen is 0.05 Nm 3 per t of the molten iron. / (Min · t) or more and 0.10 Nm 3 / (min · t) or less, and the height from the bath surface of the outlet of the gaseous oxygen of the lance for gaseous oxygen supply is 0.3 m or more and 0.7 m or less The method for dephosphorizing hot metal according to claim 1 or 2 , characterized in that
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