JP2016148075A - Method for refining molten iron - Google Patents
Method for refining molten iron Download PDFInfo
- Publication number
- JP2016148075A JP2016148075A JP2015024951A JP2015024951A JP2016148075A JP 2016148075 A JP2016148075 A JP 2016148075A JP 2015024951 A JP2015024951 A JP 2015024951A JP 2015024951 A JP2015024951 A JP 2015024951A JP 2016148075 A JP2016148075 A JP 2016148075A
- Authority
- JP
- Japan
- Prior art keywords
- hot metal
- desiliconization
- mass
- blast furnace
- refining
- 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.)
- Granted
Links
Abstract
Description
本発明は、珪素濃度が０．４５質量％以上の溶銑から高純度鋼を製造するのに適した溶銑の精錬方法に関するものである。 The present invention relates to a hot metal refining method suitable for producing high purity steel from hot metal having a silicon concentration of 0.45 mass% or more.
近年、Ｐ，Ｓ，およびＣ等の含有量を極低レベルにまで低減させた高純度鋼の製造技術に関し、各種技術が開発されている（例えば、特許文献１）。 In recent years, various techniques have been developed for manufacturing technology of high-purity steel in which the contents of P, S, C, and the like are reduced to an extremely low level (for example, Patent Document 1).
従来、これらの高純度鋼の製造には、Ｓｉ等の含有率の低い原料が使用されてきた。しかし、昨今の鉄鋼業界における厳しい価格競争の中、製銑工程においては原料価格を抑制すべく、Ｓｉ等の含有率の高い原料（いわゆる「劣質原料」）へのシフトが行われており、溶銑中のSi濃度が増加する傾向にある。これらの劣質原料を使用しつつ、製鋼工程においては、従来同様に質の高い高純度鋼を、効率よく、かつ、低コストに製造する技術への要求が高まっている。 Conventionally, raw materials having a low content such as Si have been used for the production of these high purity steels. However, in the recent severe price competition in the steel industry, in the ironmaking process, there has been a shift to raw materials with a high content such as Si (so-called “poor materials”) in order to reduce raw material prices. There is a tendency that the Si concentration in the medium increases. While using these inferior raw materials, in the steel making process, there is an increasing demand for techniques for producing high-quality high-purity steel as efficiently and at low cost as before.
高炉から出銑された溶銑中のＳｉ濃度が高い場合、次の製鋼工程での精錬剤使用量が増大し、そのコストが増大するため、一般に、溶銑の脱燐処理に先立って、高炉から出銑された溶銑中のＳｉ濃度を低下させる処理（以下、予備脱珪処理）が行われる。 When the concentration of Si in the hot metal discharged from the blast furnace is high, the amount of refining agent used in the next steelmaking process increases and the cost increases. Therefore, generally, prior to the dephosphorization treatment of the hot metal, A treatment for reducing the Si concentration in the molten hot metal (hereinafter, preliminary desiliconization treatment) is performed.
予備脱珪処理の具体的手法としては、高炉鋳床で脱珪剤を添加する方法、もしくは、溶銑を溶銑輸送容器（混銑車や溶銑鍋等）に移し替えた後に、溶銑輸送容器内に脱珪剤を吹込む方法の何れかが、広く採用されている。 As a specific method of preliminary desiliconization treatment, a method of adding a desiliconizing agent in a blast furnace casting floor, or after transferring hot metal to a hot metal transporting container (such as a kneading car or hot metal ladle) and then removing it into the hot metal transporting container. Any of the methods of blowing a silica is widely adopted.
このうち、高炉鋳床で脱珪剤を添加する方法では、脱珪幅（Δ［％Ｓｉ］）を確保しようとすると、大量の脱珪剤を一気に添加する必要がある。しかし、大量の脱珪剤を一気に添加した場合、スラグのスロッピングやフォーミングを引き起こすため、従来の実操業では、０．０５％程度の脱珪幅（Δ［％Ｓｉ］）しか得られず、脱珪効率が悪いという問題があった。 Among these, in the method of adding a desiliconizing agent in a blast furnace cast floor, it is necessary to add a large amount of desiliconizing agent all at once in order to secure a desiliconization width (Δ [% Si]). However, when a large amount of desiliconizing agent is added at once, it causes slopping and forming of slag, so in the conventional actual operation, only a desiliconization width of about 0.05% (Δ [% Si]) can be obtained. There was a problem that the desiliconization efficiency was poor.
また、溶銑輸送容器内に脱珪剤を吹込む方法では、脱珪剤の供給速度が脱珪反応を律速するが、脱珪剤の供給速度は、既存の装置条件（吹込みランスの強度やノズル径、フリーボード等）によって、所定速度に制限されている。このため、脱珪幅Δ［％Ｓｉ］を大きく確保しようとすると、長時間に亘って脱珪剤の供給を行う必要があるため、脱珪処理に時間がかかり、生産性が悪い（＝短時間処理ができない）という問題があった。 In addition, in the method in which the desiliconizing agent is blown into the hot metal transport container, the supply rate of the desiliconizing agent determines the desiliconization reaction. However, the supply rate of the desiliconizing agent depends on the existing equipment conditions (strength of the blowing lance, Nozzle diameter, free board, etc.) are limited to a predetermined speed. For this reason, in order to secure a large silicon removal width Δ [% Si], it is necessary to supply the silicon removal agent over a long period of time, so it takes time for the silicon removal treatment and the productivity is low (= short) There was a problem that time processing was not possible.
その他、高炉鋳床での脱珪剤添加と、溶銑輸送容器内での脱珪剤吹込みを組み合わせて行う技術も開示されている（特許文献２）。 In addition, a technique for performing a combination of adding a desiliconizing agent in a blast furnace casting and blowing a desiliconizing agent in a hot metal transport container is also disclosed (Patent Document 2).
この特許文献２の技術は、具体的には、高炉鋳床での脱珪剤添加と、溶銑輸送容器内での脱珪剤吹込みを組み合わせて行いつつ、溶銑輸送容器内に入れ置きした鉄スクラップの配合比率に応じて脱珪剤における気体酸素源と固体酸素源の使用比率を調整することによって、鉄スクラップの装入量に見合った発熱量に制御する技術であり、明細書中には、出銑時の「珪素濃度が０．４５質量％未満」の溶銑を対象として、溶銑中珪素濃度が０．１０質量％となるまで脱珪処理を行う例が開示されている。 Specifically, the technique of Patent Document 2 is a combination of adding a desiliconizing agent in a blast furnace casting floor and blowing a desiliconizing agent in a hot metal transport container, and placing the iron in the hot metal transport container. It is a technology to control the heat generation amount corresponding to the amount of iron scrap charged by adjusting the usage ratio of gaseous oxygen source and solid oxygen source in the desiliconization agent according to the mixing ratio of scrap, An example is disclosed in which desiliconization treatment is performed until the silicon concentration in the hot metal reaches 0.10% by mass, with the hot metal having a “silicon concentration of less than 0.45% by mass” at the time of brewing.
しかし、実際の操業では、珪素濃度が０．２質量％未満となるまで脱珪処理を行うと、脱炭反応が進行してスラグのフォーミングが起こり始めるため、スロッピングを回避するためには、脱珪剤の添加速度を落として脱珪反応を進めることが必要となり、生産性の観点から好ましくない。なお、本発明のように「珪素濃度が０．４５質量％以上」の溶銑を用い、特許文献２の手法に従って、「溶銑中珪素濃度が０．１０質量％」となるまで脱珪処理する場合、処理時間が更に必要となり、生産性が著しく悪化するため、現実の操業条件としては適さない。 However, in actual operation, when desiliconization treatment is performed until the silicon concentration is less than 0.2% by mass, decarburization reaction proceeds and slag forming begins to occur. It is necessary to proceed the desiliconization reaction by reducing the addition rate of the desiliconizing agent, which is not preferable from the viewpoint of productivity. In the case of using the hot metal having a “silicon concentration of 0.45 mass% or more” as in the present invention and performing desiliconization treatment until the “silicon concentration in the molten iron becomes 0.10 mass%” according to the technique of Patent Document 2. Further, the treatment time is further required and the productivity is remarkably deteriorated, so that it is not suitable as an actual operation condition.
本発明の目的は、前記の各問題を解決して、高純度鋼を、効率よく、かつ、低コストに製造する技術を提供することである。 An object of the present invention is to solve the above-described problems and provide a technique for producing high-purity steel efficiently and at low cost.
本発明では上記の課題を解決するための手段として、珪素濃度０．４５質量％以上の高炉溶銑から高純度鋼を溶製する溶銑の精錬方法において、転炉での脱りん、脱炭精錬に先立って、溶銑の珪素濃度を０．２質量％〜０．４質量％とする予備脱珪工程を有し、該予備脱珪工程が、前記の高炉溶銑を、高炉の鋳銑樋から溶銑輸送容器に移す過程において、流下中の溶銑に、脱珪剤として固体酸素源を投入する工程と、前記の溶銑輸送容器内で攪拌を行う工程からなる、という構成を採用した。ここで、「高炉の鋳銑樋から溶銑輸送容器に移す過程において、流下中の溶銑」とは、主樋、あるいは溶銑樋内で流下している溶銑、および、溶銑樋から溶銑搬送容器へ向けて落下している溶銑、を含むものである。 In the present invention, as a means for solving the above problems, in a hot metal refining method for melting high purity steel from a blast furnace hot metal having a silicon concentration of 0.45% by mass or more, dephosphorization and decarburization refining in a converter. Prior to this, there is a preliminary desiliconization step in which the silicon concentration of the hot metal is 0.2 mass% to 0.4 mass%, and this preliminary desiliconization step transports the blast furnace hot metal from the blast furnace cast iron to the hot metal. In the process of transferring to the container, a configuration was adopted which consisted of a step of introducing a solid oxygen source as a desiliconizing agent into the hot metal flowing down and a step of stirring in the hot metal transport container. Here, “in the process of transferring from the blast furnace cast iron to the hot metal transport vessel” means that the hot metal flowing down is the main iron or the hot metal flowing down in the hot metal, and from the hot metal to the hot metal transfer container. Hot metal falling down.
請求項２記載の発明のように、前記の固体酸素源として、密度が３５００ｋｇ／ｍ３以上、かつ、酸素ガス換算の酸素含有量が０．１３Ｎｍ３／ｋｇ以上の固体酸素源を用いることが好ましい。 According to a second aspect of the present invention, as the solid oxygen source, a solid oxygen source having a density of 3500 kg / m 3 or more and an oxygen content in terms of oxygen gas of 0.13 Nm 3 / kg or more is used. preferable.
請求項３記載の発明のように、前記の固体酸素源として、粒径が、球相当径で５ｍｍ〜２５ｍｍの固体酸素源を用いることが好ましい。 As in the third aspect of the invention, it is preferable to use a solid oxygen source having a sphere equivalent diameter of 5 mm to 25 mm as the solid oxygen source.
請求項４記載の発明のように、前記の溶銑輸送容器内で攪拌を行う際に、脱珪剤として鉄を主成分とする脱珪剤を吹き込むことが好ましい。 As in the fourth aspect of the present invention, it is preferable to blow in a desiliconizing agent mainly composed of iron as a desiliconizing agent when stirring in the hot metal transport container.
請求項５記載の発明のように、前記の溶銑輸送容器として、混銑車を用いることが好ましい。 As in the fifth aspect of the invention, it is preferable to use a kneading vehicle as the hot metal transport container.
背景技術の欄に記載のように、従来の予備脱珪技術のうち、高炉鋳床で脱珪剤を添加する方法では、０．０５％程度の脱珪幅（Δ［％Ｓｉ］）しか得られず、脱珪効率が悪いという問題があり、溶銑輸送容器内に脱珪剤を吹込む方法では、生産性が悪い（＝短時間処理ができない）という問題があったのに対し、本発明では、予備脱珪工程を、高炉溶銑を、高炉の鋳銑樋から溶銑輸送容器に移す過程において、流下中の溶銑に、脱珪剤として固体酸素源を投入する工程（以下、第一の予備脱珪工程という）と、この溶銑輸送容器内で攪拌を行う工程（以下、第二の予備脱珪工程という）からなるものとするという構成を採用することにより、これらの問題を合わせて解決している。本発明者らは、各種検討の結果、高炉の鋳銑樋から溶銑輸送容器に移す過程において、流下中の溶銑に、脱珪剤として固体酸素源を投入しただけでは、投入した脱珪剤の一部しか脱珪に寄与出来ないことを見出した。本発明はこの知見に基づくものであり、前記の「第一の予備脱珪工程」に続いて、「第二の予備脱珪工程」を設けることで、投入された脱珪剤のうち、脱珪に寄与する割合の改善を図ることによって、前記の問題を解決した。 As described in the background art section, among the conventional preliminary desiliconization techniques, the method of adding a desiliconization agent in a blast furnace casting floor only obtains a desiliconization width of about 0.05% (Δ [% Si]). However, there is a problem that the desiliconization efficiency is poor, and the method of blowing the desiliconizing agent into the hot metal transport container has a problem that productivity is low (= cannot be processed for a short time), whereas the present invention Then, in the process of transferring the blast furnace hot metal from the blast furnace cast iron to the hot metal transport container, the preliminary desiliconization process is a process in which a solid oxygen source is added as a desiliconizing agent to the hot metal flowing down (hereinafter referred to as the first preliminary process). By adopting a configuration consisting of a desiliconization step) and a step of stirring in the hot metal transport container (hereinafter referred to as a second preliminary desiliconization step), these problems can be solved together. ing. As a result of various studies, the present inventors, in the process of transferring from the cast iron of the blast furnace to the hot metal transport container, just by introducing a solid oxygen source as a desiliconizing agent into the molten iron that is flowing down, We found that only a part can contribute to desiliconization. The present invention is based on this finding, and by providing a “second preliminary desiliconization step” subsequent to the “first preliminary desiliconization step”, the desiliconizing agent that has been put in is removed. The above problem was solved by improving the ratio of contribution to silica.
なお、脱珪工程と、脱硫工程と、脱燐工程と、脱炭工程を有し、この順序で精錬する溶銑の精錬技術は、例えば、「鉄と鋼 第７４年（１９８８） 第２号 ２７０〜２７７頁」に開示されているが、この技術は、脱珪工程において、珪素濃度を０．１５％以下にまで低減させる処理を必須とする技術である。従来のように、Ｓｉ等の含有率の低い高炉溶銑の場合、この従来技術でも、特段の問題はないが、珪素濃度０．４５質量％以上の高炉溶銑を用いる場合、珪素濃度を０．１５質量％未満にまで低減させようとした場合、脱珪剤（ＦｅＯを含有するフラックス）が相当量必要になり、脱珪処理時間は、脱珪剤の使用量とともに増加するため、脱珪処理に時間がかかり生産性が低下する問題がある。 In addition, the refining technique of the hot metal which has a desiliconization process, a desulfurization process, a dephosphorization process, and a decarburization process, and refines in this order, for example, "Iron and steel 74th (1988) No. 2 270" ˜page 277 ”, this technique is a technique that essentially requires a treatment for reducing the silicon concentration to 0.15% or less in the desiliconization step. In the case of blast furnace hot metal having a low content of Si or the like as in the prior art, there is no particular problem with this prior art, but when using a blast furnace hot metal having a silicon concentration of 0.45% by mass or more, the silicon concentration is 0.15. When trying to reduce it to less than mass%, a considerable amount of desiliconizing agent (flux containing FeO) is required, and the desiliconizing treatment time increases with the amount of desiliconizing agent used. There is a problem that it takes time and productivity is lowered.
これに対し、「脱珪処理後の珪素濃度を０．２質量％〜０．４質量％」に留める本発明によれば、上記技術と比較して、脱珪剤の使用量を低減してボトルネック工程となる脱珪処理時間を短縮することができ、生産性の向上を図ることができる。また、脱珪剤の使用量を低減した結果、従来脱珪剤を大量に使用した際生じていた各問題（脱硫反応を阻害する問題や、脱燐工程で復硫が生じる問題、或いは脱珪時のスロッピングの問題）を回避することができる。 On the other hand, according to the present invention that keeps the silicon concentration after desiliconization treatment to 0.2 mass% to 0.4 mass%, the amount of desiliconization agent used is reduced compared to the above technique. It is possible to shorten the desiliconization processing time as a bottleneck process, and to improve productivity. In addition, as a result of reducing the amount of desiliconizing agent used, each problem that occurred when a large amount of desiliconizing agent was used (problem that obstructs desulfurization reaction, problem of desulfurization in dephosphorization process, or desiliconization) Time slopping problem) can be avoided.
また、上記の脱燐処理を溶銑鍋（フリーボード部がない容器）で行う場合、脱燐処理時のスラグフォーミング回避の観点から、事前の脱珪工程で、珪素濃度を「０．１５質量％未満」程度にまで低減させることが要求されるが、本発明のように、脱燐処理を転炉型反応容器で行う構成とすることにより、低塩基度での脱りんが可能になり、ある程度のＳｉ濃度が許容され、事前の脱珪工程における脱珪処理後珪素濃度の目標レベルを「０．２質量％〜０．４質量％」に高めることができる。前記のように、珪素濃度が０．２質量％未満となるまで脱珪処理を行うと、脱炭反応が進行してスラグのフォーミングが起こり始めるが、脱珪処理後珪素濃度を「０．２質量％〜０．４質量％」に留めることにより、スロッピングを確実に回避することができる。なお、脱珪工程で、溶銑中に残存したＳｉは、脱燐工程でスラグ化して溶銑から除かれる。また、脱珪処理後珪素濃度を「０．２質量％〜０．４質量％」に留めることにより、脱燐工程初期におけるスラグボリュームを充分確保し、スラグボリューム確保を目的とした副原料（蛍石等、）使用量を低減するとともに、石灰源の滓化を促進して、脱燐効率を高めることができる。 Further, when the above dephosphorization process is performed in a hot metal ladle (a container having no free board part), from the viewpoint of avoiding slag forming during the dephosphorization process, the silicon concentration is set to “0.15% by mass in the prior desiliconization process. It is required to be reduced to about “less than”. However, by adopting a configuration in which the dephosphorization treatment is performed in the converter type reaction vessel as in the present invention, dephosphorization at a low basicity becomes possible to some extent. Therefore, the target level of the silicon concentration after the desiliconization treatment in the prior desiliconization process can be increased to “0.2 mass% to 0.4 mass%”. As described above, when the desiliconization treatment is performed until the silicon concentration is less than 0.2% by mass, the decarburization reaction proceeds and slag forming begins to occur. By staying at “mass% to 0.4 mass%”, it is possible to reliably avoid the slopping. Note that Si remaining in the hot metal in the desiliconization process is slagted in the dephosphorization process and removed from the hot metal. In addition, by keeping the silicon concentration at “0.2 mass% to 0.4 mass%” after the desiliconization treatment, a sufficient amount of slag volume at the initial stage of the dephosphorization process is secured, and a secondary material (fluorescent material) for the purpose of securing the slag volume is secured. (Stone, etc.) It is possible to increase the dephosphorization efficiency by reducing the amount used and promoting the hatching of the lime source.
固体酸素源の密度、酸素含有量、粒径を、それぞれ、請求項２、３に記載の範囲とすることにより、固体酸素源の溶解速度、すなわち、脱珪反応の反応速度が最適に制御でき、搬送容器に移し替え時、あるいはそれに引き続くスロッピングを確実に回避することができる。 By setting the density, oxygen content, and particle size of the solid oxygen source within the ranges described in claims 2 and 3, respectively, the dissolution rate of the solid oxygen source, that is, the reaction rate of the desiliconization reaction can be optimally controlled. In addition, it is possible to reliably avoid the slopping during the transfer to the transport container or subsequent.
高炉溶銑の珪素濃度が、例えば、０．７質量％以上等になる場合にも、請求項４記載の発明のように、前記の溶銑輸送容器内で攪拌を行う際に、脱珪剤として酸化鉄を主成分とする脱珪剤を吹き込む手法を併用することにより、上記同様の効果を得ることができる。 Even when the silicon concentration of the blast furnace hot metal becomes, for example, 0.7% by mass or more, when the stirring is performed in the hot metal transport container as described in claim 4, it is oxidized as a desiliconizing agent. The effect similar to the above can be obtained by using a method of blowing a desiliconizing agent mainly composed of iron.
以下に本発明の好ましい実施形態を示す。本実施形態の溶銑の精錬方法は、図１に示すように、脱珪工程〜脱硫工程〜脱燐工程〜脱炭工程の順に、各工程を経て、珪素濃度０．４５質量％以上の高炉溶銑から高純度鋼を溶製する溶銑の精錬方法である。以下、各工程について詳述する。 Preferred embodiments of the present invention are shown below. As shown in FIG. 1, the hot metal refining method of the present embodiment is blast furnace hot metal having a silicon concentration of 0.45% by mass or more through each step in the order of desiliconization step, desulfurization step, dephosphorization step, and decarburization step. This is a method for refining hot metal from high purity steel. Hereinafter, each process is explained in full detail.
＜第一の予備脱珪工程＞
図２に示すように、高炉１から出銑された溶銑は、高炉鋳床２を経て、溶銑搬送用の混銑車３に挿入される。高炉鋳床２には、高炉から出銑された溶銑や溶滓などの高温流体を取扱うための設備が配置されており、まず主樋４において、溶銑と溶滓とは比重差により分離される。その後、溶銑は溶銑樋５、通って混銑車３の注入口まで導かれるように各樋が構築されている。第一の予備脱珪工程では、溶銑を鋳銑樋から混銑車に移す過程において、流下中の溶銑に、脱珪剤として固体酸素源が投入されて、脱珪処理（[Ｓｉ]＋Ｏ２→ＳｉＯ２。ここで、[Ｓｉ] ：溶銑中の珪素、ＳｉＯ２：スラグ中のＳｉＯ２。）が行われる。前記のように、ここで、「高炉の鋳銑樋から溶銑輸送容器に移す過程において、流下中の溶銑」とは、主樋、あるいは溶銑樋内で流下している溶銑、および、溶銑樋から溶銑搬送容器へ向けて落下している溶銑、の双方を含むものである。
<First preliminary desiliconization process>
As shown in FIG. 2, the hot metal discharged from the blast furnace 1 is inserted into a kneading wheel 3 for hot metal transfer through a blast furnace casting floor 2. The blast furnace casting floor 2 is provided with equipment for handling high-temperature fluid such as hot metal and hot metal discharged from the blast furnace. First, in the main iron 4, the hot metal and hot metal are separated by the specific gravity difference. . After that, each hot metal is constructed so that the hot metal is led to the injection port of the kneading wheel 3 through the hot metal 5. In the first preliminary desiliconization step, in the process of transferring the hot metal from the cast iron to the kneading wheel, a solid oxygen source is introduced as a desiliconizing agent into the hot metal flowing down and desiliconization treatment ([Si] + O 2 → . SiO 2 where, [Si]: silicon in the molten iron, SiO 2:. SiO 2 in the slag) is performed. As described above, here, “in the process of transferring from the blast furnace cast iron to the hot metal transport container, the hot metal flowing down” means the hot metal flowing down in the hot metal or the hot metal and hot metal. It includes both hot metal falling toward the hot metal transport container.
固体酸素源としては、焼結鉱粉、ダストペレット、ミルスケールの少なくとも何れかを用いることが好ましい。焼結鉱粉は、焼結工場の集塵機で集積されるもので、密度と酸素含有量が本発明条件を満足し易く、かつ高炉一貫製鉄所では、容易にかつ安価に入手できるので、固体酸素源としては好ましい。ダストペレットは、転炉で発生する転炉ダスト等を原料として粒状に成型したもので、密度が小さいという欠点はあるが、比較的安価に製造可能である。ミルスケールは、圧延工程でのスケールを粉砕したもので、多くの製鉄所で発生し、安価で利用出来るため好ましい。但し、発生量が少ないので大量には使用困難である。これら固体酸素源の１種又は２種以上を造粒又は塊成化して使用することもできる。 As the solid oxygen source, it is preferable to use at least one of sintered ore powder, dust pellets, and mill scale. Sintered ore powder is collected by a dust collector in a sintering plant, and its density and oxygen content are easy to satisfy the conditions of the present invention, and can be obtained easily and inexpensively at the blast furnace integrated steelworks. Preferred as a source. Dust pellets are formed by converting converter dust and the like generated in a converter into granules, and have the disadvantage of low density, but can be manufactured relatively inexpensively. The mill scale is preferable because it is obtained by pulverizing the scale in the rolling process, is generated at many steelworks, and can be used at low cost. However, since the amount generated is small, it is difficult to use in large quantities. One or more of these solid oxygen sources can be granulated or agglomerated for use.
なお、本実施形態では、脱珪剤として、密度３５００ｋｇ／ｍ３以上、酸素含有量（酸素ガス換算）０．１３Ｎｍ３／ｋｇ以上、粒径が（球相当径）５ｍｍ〜２５ｍｍの固体酸素源を使用することにより、脱珪反応の反応速度を最適に制御して、スロッピングの回避を図っている。脱珪剤の密度が３５００ｋｇ／ｍ３未満であると、必要な添加量に対し、体積が大きくなり、フリーボード体積を占有してしまい、必要な添加量が確保できなくなること、更には、フォーミングしたスラグを収容できずに溢れ、スロッピングが起きるからである。また、酸素含有量が０．１３Ｎｍ３未満であると、やはり脱珪に必要な酸素量が確保できなくなるためである。また固体酸素源として、粒径が、球相当径で５ｍｍ〜２５ｍｍの固体酸素源を用いることが好ましい。これは、高炉から溶銑輸送容器に移す過程において脱珪剤を添加する際に、添加速度を高めるた場合、粒径が５ｍｍ未満であると、一気に反応が進み、スラグのフォーミング、スロッピングが激しくなるからである。また２５ｍｍ超では、溶銑輸送容器での撹拌を行なっても比表面積が小さく、撹拌を行なっても反応が進まなくなるためである。 In this embodiment, as a desiliconizing agent, a solid oxygen source having a density of 3500 kg / m 3 or more, an oxygen content (in terms of oxygen gas) of 0.13 Nm 3 / kg or more, and a particle size (sphere equivalent diameter) of 5 mm to 25 mm. By using this, the reaction rate of the desiliconization reaction is optimally controlled to avoid slipping. If the density of the desiliconizing agent is less than 3500 kg / m 3 , the volume becomes larger than the required amount added, and the free board volume is occupied, and the necessary amount added cannot be secured. This is because the slag overflows without being able to be accommodated and slopping occurs. Further, if the oxygen content is less than 0.13 Nm 3 , the oxygen amount necessary for desiliconization cannot be secured. As the solid oxygen source, it is preferable to use a solid oxygen source having a particle diameter equivalent to a sphere of 5 mm to 25 mm. This is because when adding the desiliconization agent in the process of transferring from the blast furnace to the hot metal transport container, when the addition rate is increased, if the particle size is less than 5 mm, the reaction proceeds at a stretch, and slag forming and slopping are intense. Because it becomes. On the other hand, if it exceeds 25 mm, the specific surface area is small even if stirring is performed in the hot metal transport container, and the reaction does not proceed even if stirring is performed.
前記のように、本発明者らは、各種検討の結果、高炉の鋳銑樋から溶銑輸送容器に移す過程において、流下中の溶銑に、脱珪剤として固体酸素源を投入しただけでは、投入した脱珪剤の一部しか脱珪に寄与出来ないことを見出した。本発明はこの知見に基づくものであり「第一の予備脱珪工程」に続いて、「第二の予備脱珪工程」を設けることで、投入された脱珪剤のうち、脱珪に寄与する割合の改善を図っている。 As described above, the present inventors, as a result of various studies, in the process of transferring from the blast furnace cast iron to the hot metal transport container, just by adding a solid oxygen source as a desiliconizing agent to the hot metal flowing down, It was found that only a part of the desiliconizing agent that was made can contribute to desiliconization. The present invention is based on this finding, and by providing a “second preliminary desiliconization step” following the “first preliminary desiliconization step”, among the input desiliconizers, it contributes to desiliconization. To improve the percentage of
＜第二の予備脱珪工程＞
第二の予備脱珪工程では、図３に示すように、混銑車３内の溶銑の撹拌が行われる。脱珪反応は、スラグ/溶銑界面で進行するため、撹拌によって反応界面積を増加させ、反応促進を図ることが出来る。撹拌手段は特に限定されず、機械式攪拌、ガス吹き式攪拌等、任意の手段を採用することができる。
<Second preliminary desiliconization process>
In the second preliminary desiliconization step, as shown in FIG. 3, the hot metal in the kneading wheel 3 is stirred. Since the desiliconization reaction proceeds at the slag / hot metal interface, the reaction interface area can be increased by stirring to promote the reaction. The stirring means is not particularly limited, and any means such as mechanical stirring and gas blowing stirring can be adopted.
本実施形態では、混銑車３の上方に配置したランス６から窒素ガスを吹き込むことにより、溶銑の撹拌を行っている。この撹拌により、「第一の予備脱珪工程」で投入された固体酸素源を利用する反応を促進させ、珪素濃度を０．２質量％〜０．４質量％とする脱珪処理を行っている。前記のように、珪素濃度が０．２質量％未満となるまで脱珪処理を行うと、脱炭反応が進行してスラグのフォーミングが起こり始めるが、脱珪処理後珪素濃度を「０．２質量％〜０．４質量％」に留めることにより、スロッピングを確実に回避することができる。 In the present embodiment, the hot metal is stirred by blowing nitrogen gas from the lance 6 disposed above the kneading wheel 3. By this stirring, the reaction utilizing the solid oxygen source introduced in the “first preliminary desiliconization step” is promoted, and the desiliconization treatment is performed so that the silicon concentration is 0.2 mass% to 0.4 mass%. Yes. As described above, when the desiliconization treatment is performed until the silicon concentration is less than 0.2% by mass, the decarburization reaction proceeds and slag forming begins to occur. By staying at “mass% to 0.4 mass%”, it is possible to reliably avoid the slopping.
固体酸素源の不足分は、ランスを介した微粉吹き込みにより追加投入することができる。ここで吹き込む固体酸素源としては、酸化鉄を主成分とする脱珪剤を用いることが好ましい。 The shortage of solid oxygen source can be additionally charged by blowing fine powder through a lance. As the solid oxygen source to be blown in here, it is preferable to use a desiliconizing agent mainly composed of iron oxide.
＜脱硫工程＞
前記の脱珪工程を経て、脱珪スラグを排出した後、溶銑は、脱硫処理用の精錬容器に挿入され、脱硫剤を添加して脱硫処理（[Ｓ]＋ＣａＯ→ＣａＳ＋[Ｏ]）が行われる。ここで、精錬容器や撹拌手段は、特に限定されず、溶銑鍋や混銑車での脱硫剤インジェクション方式や、溶銑鍋での機械撹拌方式を採用することができる。
<Desulfurization process>
After discharging the desiliconization slag through the desiliconization process, the hot metal is inserted into a refining vessel for desulfurization treatment, and a desulfurization agent is added to perform desulfurization treatment ([S] + CaO → CaS + [O]). Is called. Here, the refining vessel and the stirring means are not particularly limited, and a desulfurization agent injection method in a hot metal ladle or a kneading vehicle, or a mechanical stirring method in a hot metal ladle can be adopted.
＜脱燐工程＞
脱燐反応は、２[Ｐ]＋５[Ｏ]＋３ＣａＯ→３ＣａＯ・Ｐ２Ｏ５のように進行する。ここで、 [Ｐ]：溶銑中の燐、[Ｏ]：溶銑中の酸素（酸素ガスあるいは酸化鉄）、ＣａＯ：スラグ中のＣａＯ、ＣａＯ・Ｐ２Ｏ５：スラグ中のＣａＯに固定されたＰ２Ｏ５である。
<Dephosphorization process>
The dephosphorization reaction proceeds as 2 [P] +5 [O] + 3CaO → 3CaO · P 2 O 5 . Here, [P]: phosphorus in hot metal, [O]: oxygen (oxygen gas or iron oxide) in hot metal, CaO: CaO in slag, CaO · P 2 O 5 : fixed to CaO in slag it is P 2 O 5.
前記の工程を経て、脱硫スラグを排出した後、溶銑は、脱燐工程用の転炉型反応容器に挿入され、脱燐剤を添加して、上底吹き撹拌により、脱燐処理が行われる。従来技術のように、脱燐処理を溶銑鍋（フリーボード部が小さい容器）で行う場合、脱燐処理時のスラグフォーミング回避の観点から、事前の脱珪工程で、珪素濃度を「０．１５質量％未満」程度にまで低減させることが要求されるが、本実施形態のように、脱燐処理を転炉型反応容器で行う構成とすることにより、ある程度のスラグフォーミングが許容され、事前の脱珪工程における脱珪処理後珪素濃度の目標レベルを「０．２質量％〜０．４質量％」に高めることができる。脱珪工程で、溶銑中に残存したＳｉは、この脱燐工程でスラグ化して溶銑から除かれる。 After discharging the desulfurization slag through the above steps, the hot metal is inserted into a converter reactor for the dephosphorization step, and a dephosphorization process is performed by adding a dephosphorization agent and stirring the top bottom. . When the dephosphorization process is performed in a hot metal pan (a container having a small free board portion) as in the prior art, the silicon concentration is set to “0.15” in the prior desiliconization process from the viewpoint of avoiding slag forming during the dephosphorization process. It is required to be reduced to a level of less than “mass%”. However, by adopting a configuration in which the dephosphorization process is performed in a converter reactor as in this embodiment, a certain amount of slag forming is allowed, The target level of the silicon concentration after the desiliconization process in the desiliconization process can be increased to “0.2 mass% to 0.4 mass%”. Si remaining in the hot metal in the desiliconization process is converted into slag and removed from the hot metal in the dephosphorization process.
本実施形態では、前記のように、脱珪処理後珪素濃度を「０．２質量％〜０．４質量％」に留めることにより、脱燐工程初期におけるスラグボリュームを充分確保し、スラグボリューム確保を目的とした副原料（蛍石等、）使用量を低減するとともに、石灰源の滓化を促進して、脱燐効率を高めている。 In the present embodiment, as described above, the silicon concentration after the desiliconization treatment is kept at “0.2 mass% to 0.4 mass%”, thereby sufficiently securing the slag volume at the initial stage of the dephosphorization process and securing the slag volume. In addition to reducing the amount of secondary materials (fluorite, etc.) used for the purpose of promoting the hatching of lime sources, the dephosphorization efficiency is increased.
＜その他の工程＞
必要に応じて、脱燐処理後の溶銑に脱炭剤を添加して脱炭処理を行う脱炭工程や、その後の２次精錬（脱ガス、脱硫）工程を追加することもできる。
<Other processes>
If necessary, a decarburization process in which a decarburizing agent is added to the hot metal after the dephosphorization process to perform a decarburization process, and a subsequent secondary refining (degassing, desulfurization) process may be added.
高Ｓｉ溶銑を、混銑車脱珪→（スラグ排出）→鍋脱硫→転炉脱燐のプロセスで処理した結果を下記（表１）の実施例１〜３、比較例１〜４に示している。なお、下記表１において、「添加場所Ａ」は鋳銑樋、「添加場所Ｂ」は溶銑搬送容器である混銑車を示す。「含有酸素量」は、単位質量あたりの脱珪剤に含まれる酸素ガス体積換算の酸素量(Ｎｍ３／ｋｇ)を意味する。「脱珪時間」は、混銑車での脱珪開始から脱珪処理終了までの時間（ｍｉｎ）である。高炉での脱珪処理については、脱珪を行なった場合、行わない場合でも溶銑の移し替えに同様の時間を要するため、除外している。「ダストペレット」としては、転炉ダストを造粒したものを用いた。 The results of treating the high Si hot metal by the process of kneading car desiliconization → (slag discharge) → pan desulfurization → converter dephosphorization are shown in Examples 1 to 3 and Comparative Examples 1 to 4 below (Table 1). . In Table 1 below, “addition location A” indicates a cast iron, and “addition location B” indicates a kneading vehicle that is a hot metal transfer container. “Oxygen content” means an oxygen amount (Nm 3 / kg) in terms of oxygen gas volume contained in the desiliconizing agent per unit mass. “Desiliconization time” is the time (min) from the start of desiliconization in a chaotic vehicle to the end of the desiliconization process. The desiliconization treatment in the blast furnace is excluded because it takes a similar time to transfer the hot metal even when desiliconization is not performed. As the “dust pellet”, granulated converter dust was used.
実施例１〜３は、何れも、第一の予備脱珪工程後に、第二の予備脱珪工程を行って、脱珪処理後の珪素濃度を０．２質量％〜０．４質量％とした例である。実施例１〜３の何れも、短時間で効率よく脱珪処理を行うことができた。 In each of Examples 1 to 3, after the first preliminary desiliconization step, the second preliminary desiliconization step is performed, and the silicon concentration after the desiliconization treatment is 0.2 mass% to 0.4 mass%. This is an example. In all of Examples 1 to 3, the desiliconization treatment could be performed efficiently in a short time.
比較例１は、第二の予備脱珪工程を行わない例である。混銑車３では溶銑攪拌を行わず、鋳銑樋の流下溶銑への投入のみであったため、脱珪効率が低下した。その上、処理後Siも高く十分な脱珪が確保できず、転炉型脱燐炉での脱燐も悪化した。
比較例２は、第一の予備脱珪工程を行わない例である。脱珪剤を混銑車３の溶銑中に吹き込んだ。吹き込む際に窒素ガスを７００Ｎｍ３／ｈ使用した。脱珪剤の吹込速度律速の為に、処理時間が長く、脱珪処理率が低かった。
比較例３は、第一の予備脱珪工程を行わない例である。脱珪剤を混銑車３内の溶銑に上方添加し、窒素ガス７００Ｎｍ３／ｈを吹込んで溶銑攪拌を行った。脱珪処理にてスロッピングが多発した。このため脱珪剤添加速度をおとしたので所要時間は長時間となり、また脱珪スラグ中の未反応酸化鉄ＦｅＯ＋Ｆｅ２Ｏ３が多くなった。
比較例４は、予備脱珪後の珪素濃度を、０．２質量％未満とした例である。第一の予備脱珪工程に続く、第二の予備脱珪工程で、大量の脱珪剤を窒素ガス７００Ｎｍ３／ｈで吹込み、脱珪処理後の溶銑を低Ｓｉとしたため、脱炭反応が進行してスラグのフォーミングが起こり始め、スロッピングが多発した。このため脱珪処理中断を余儀なくされ。処理終了までに長時間を要した。
Comparative Example 1 is an example in which the second preliminary desiliconization step is not performed. In the kneading wheel 3, the hot metal stirring was not performed, and only the casting iron was poured into the flowing hot metal, so that the desiliconization efficiency was lowered. In addition, the Si after treatment was high and sufficient desiliconization could not be secured, and the dephosphorization in the converter dephosphorization furnace deteriorated.
Comparative Example 2 is an example in which the first preliminary desiliconization step is not performed. A desiliconizing agent was blown into the hot metal of the kneading vehicle 3. Nitrogen gas was used at 700 Nm 3 / h when blowing. Due to the rate control of the desiliconizing agent, the treatment time was long and the desiliconization rate was low.
Comparative Example 3 is an example in which the first preliminary desiliconization step is not performed. A desiliconizing agent was added upward to the hot metal in the kneading wheel 3 and nitrogen gas 700 Nm 3 / h was blown to perform hot metal stirring. Slopping occurred frequently during the desiliconization process. For this reason, since the desiliconizing agent addition speed was reduced, the time required was long and unreacted iron oxide FeO + Fe 2 O 3 in the desiliconized slag increased.
Comparative Example 4 is an example in which the silicon concentration after preliminary desiliconization is less than 0.2% by mass. In the second preliminary desiliconization process following the first preliminary desiliconization process, a large amount of desiliconizing agent was blown in with nitrogen gas 700Nm 3 / h, and the molten iron after desiliconization treatment was made to be low Si. Progressed and slag forming began to occur and slopping occurred frequently. For this reason, the desiliconization process is forced to be interrupted. It took a long time to complete the process.
上記表１の脱珪処理後の溶銑の脱燐炉として転炉型反応炉を用い、下表２の条件にて脱燐処理を実施した。上記表１の「脱燐処理後」は、表２の脱燐処理(脱珪脱燐処理含む)を施した後の溶銑中のＳｉ濃度[％Ｓｉ]とＰ濃度［％Ｐ］を示す。
実施例１〜３では、上記プロセスを経て、極極低リン溶銑を得る事ができた。比較例１〜４では、何れも、脱燐効率の低下が確認され、上記プロセスを経ても、極極低リン溶銑を得る事ができなかった。 In Examples 1 to 3, extremely low phosphorus hot metal was obtained through the above process. In each of Comparative Examples 1 to 4, it was confirmed that the dephosphorization efficiency was lowered, and it was not possible to obtain extremely low phosphorus hot metal even after the above process.
１ 高炉
２ 高炉鋳床
３ 混銑車
４ 主樋
５ 溶銑樋
６ ランス
1 Blast Furnace 2 Blast Furnace Casting 3 Chaotic Wheel 4 Main Steel 5 Hot Metal 6 Lance
Claims (5)
転炉での脱りん、脱炭精錬に先立って、溶銑の珪素濃度を０．２質量％〜０．４質量％とする予備脱珪工程を有し、
該予備脱珪工程が、
前記の高炉溶銑を、高炉の鋳銑樋から溶銑輸送容器に移す過程において、流下中の溶銑に、脱珪剤として固体酸素源を投入する工程と、
前記の溶銑輸送容器内で攪拌を行う工程
からなることを特徴とする溶銑の精錬方法。 A hot metal refining method for producing high purity steel from a blast furnace hot metal having a silicon concentration of 0.45% by mass or more,
Prior to dephosphorization and decarburization refining in the converter, a preliminary desiliconization step is performed in which the silicon concentration of the hot metal is 0.2 mass% to 0.4 mass%,
The preliminary desiliconization step includes
In the process of transferring the blast furnace hot metal from the blast furnace cast iron to the hot metal transport container, a step of supplying a solid oxygen source as a desiliconizing agent to the hot metal flowing down;
A method for refining hot metal, comprising the step of stirring in the hot metal transport container.
密度が３５００ｋｇ／ｍ３以上、かつ、酸素ガス換算の酸素含有量が０．１３Ｎｍ３／ｋｇ以上
の固体酸素源を用いることを特徴とする請求項１記載の溶銑の精錬方法。 As the solid oxygen source,
The method for refining hot metal according to claim 1, wherein a solid oxygen source having a density of 3500 kg / m 3 or more and an oxygen content in terms of oxygen gas of 0.13 Nm 3 / kg or more is used.
粒径が、球相当径で５ｍｍ〜２５ｍｍ
の固体酸素源を用いることを特徴とする請求項１または２記載の溶銑の精錬方法。 As the solid oxygen source,
Particle diameter is 5mm to 25mm in equivalent sphere diameter
The method for refining hot metal according to claim 1 or 2, wherein a solid oxygen source is used.
ことを特徴とする請求項１〜３の何れかに記載の溶銑の精錬方法。 The hot metal refining method according to any one of claims 1 to 3, wherein a desiliconizing agent mainly composed of iron oxide is blown as a desiliconizing agent when stirring in the hot metal transport container.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2015024951A JP6500476B2 (en) | 2015-02-12 | 2015-02-12 | How to smelt molten metal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2015024951A JP6500476B2 (en) | 2015-02-12 | 2015-02-12 | How to smelt molten metal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2016148075A true JP2016148075A (en) | 2016-08-18 |
| JP6500476B2 JP6500476B2 (en) | 2019-04-17 |
Family
ID=56687755
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2015024951A Active JP6500476B2 (en) | 2015-02-12 | 2015-02-12 | How to smelt molten metal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP6500476B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2021046583A (en) * | 2019-09-19 | 2021-03-25 | Ｊｆｅスチール株式会社 | Pretreatment method for molten iron |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54103719A (en) * | 1978-02-01 | 1979-08-15 | Nisshin Steel Co Ltd | Production of low phosphorous and sulfur steel by using conuerter |
| JPS56217A (en) * | 1979-06-14 | 1981-01-06 | Nippon Steel Corp | Continuous desilicification for molten pig iron |
| JPS5735604A (en) * | 1980-08-13 | 1982-02-26 | Sumitomo Metal Ind Ltd | Pretreatment of hot iron |
| JPS6160814A (en) * | 1984-08-30 | 1986-03-28 | Sumitomo Metal Ind Ltd | Preliminary treatment of molten iron |
| JPH059534A (en) * | 1991-07-04 | 1993-01-19 | Kawasaki Steel Corp | Method for pretreating molten iron |
-
2015
- 2015-02-12 JP JP2015024951A patent/JP6500476B2/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54103719A (en) * | 1978-02-01 | 1979-08-15 | Nisshin Steel Co Ltd | Production of low phosphorous and sulfur steel by using conuerter |
| JPS56217A (en) * | 1979-06-14 | 1981-01-06 | Nippon Steel Corp | Continuous desilicification for molten pig iron |
| JPS5735604A (en) * | 1980-08-13 | 1982-02-26 | Sumitomo Metal Ind Ltd | Pretreatment of hot iron |
| JPS6160814A (en) * | 1984-08-30 | 1986-03-28 | Sumitomo Metal Ind Ltd | Preliminary treatment of molten iron |
| JPH059534A (en) * | 1991-07-04 | 1993-01-19 | Kawasaki Steel Corp | Method for pretreating molten iron |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2021046583A (en) * | 2019-09-19 | 2021-03-25 | Ｊｆｅスチール株式会社 | Pretreatment method for molten iron |
| JP7095668B2 (en) | 2019-09-19 | 2022-07-05 | Ｊｆｅスチール株式会社 | Pretreatment method for hot metal |
Also Published As
| Publication number | Publication date |
|---|---|
| JP6500476B2 (en) | 2019-04-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5573424B2 (en) | Desulfurization treatment method for molten steel | |
| WO2018135344A1 (en) | Desulfurization treatment method for molten steel, and desulfurization agent | |
| JP6481774B2 (en) | Molten iron dephosphorizing agent, refining agent and dephosphorizing method | |
| JP5807720B2 (en) | Hot metal refining method | |
| JP6693536B2 (en) | Converter steelmaking method | |
| JP2016151027A (en) | Production method of molten steel | |
| JP6222490B2 (en) | Hot phosphorus dephosphorization method | |
| JP5983492B2 (en) | Hot metal pretreatment method | |
| JP4977870B2 (en) | Steel making method | |
| JP5904238B2 (en) | Method of dephosphorizing hot metal in converter | |
| JP5233378B2 (en) | Hot phosphorus dephosphorization method | |
| JP2007262576A (en) | Method for smelting molten iron | |
| JP6500476B2 (en) | How to smelt molten metal | |
| JP6405876B2 (en) | Hot metal refining method | |
| WO2018135351A1 (en) | Molten iron dephosphorization method | |
| CN107849624B (en) | Bessemerize method | |
| JP2011184753A (en) | Method for desiliconizing molten iron | |
| JP2009114489A (en) | Method for dephosphorizing molten iron | |
| JP6658049B2 (en) | Hot metal desiliconization method | |
| JP4649694B2 (en) | Hot metal refining method | |
| CN108588340A (en) | A kind of method that low-temperature refining prepares low aluminium calcium impurities Antaciron | |
| JP2001107124A (en) | Method for dephosphorizing molten iron | |
| JP5333423B2 (en) | Hot metal dephosphorization method | |
| JP6375822B2 (en) | Hot metal desiliconization method | |
| JP5341735B2 (en) | Method for supplying gaseous oxygen and solid oxygen source in dephosphorization process |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20171005 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20180822 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20180918 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20181029 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20190219 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20190304 |
|
| R151 | Written notification of patent or utility model registration |
Ref document number: 6500476 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R151 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |