JP7476872B2 - Metal manufacturing methods - Google Patents

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JP7476872B2
JP7476872B2 JP2021194622A JP2021194622A JP7476872B2 JP 7476872 B2 JP7476872 B2 JP 7476872B2 JP 2021194622 A JP2021194622 A JP 2021194622A JP 2021194622 A JP2021194622 A JP 2021194622A JP 7476872 B2 JP7476872 B2 JP 7476872B2
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和哉 南谷
憲治 中瀬
由枝 中井
直樹 菊池
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本発明は、金属製錬用または金属精錬用の主原料もしくは副原料として用いられるリンを含有する金属酸化物から、リン濃度の低い金属を製造する方法に関する。 The present invention relates to a method for producing metals with low phosphorus concentrations from phosphorus-containing metal oxides that are used as a main or auxiliary raw material for metal smelting or refining.

近年、製鉄業における冷鉄源(鉄スクラップ等)の使用拡大の需要が高まっている。循環型社会の構築のために、鉄源リサイクルは必要不可欠であるうえ、昨今のCO削減の需要からも冷鉄源使用量増大は不可欠である。冷鉄源は酸化鉄(Fe)である鉄鉱石と異なり、溶製プロセスに還元工程を要さないためCO排出量の低減が可能であり、冷鉄源の使用量は増加の一途をたどっている。 In recent years, the demand for the expansion of the use of cold iron sources (iron scrap, etc.) in the steel industry has been increasing. In order to build a recycling-oriented society, recycling of iron sources is essential, and in light of the recent demand for reducing CO2 emissions, an increase in the use of cold iron sources is essential. Unlike iron ore, which is iron oxide ( Fe2O3 ), cold iron sources do not require a reduction process in the smelting process, making it possible to reduce CO2 emissions, and the use of cold iron sources is steadily increasing.

高炉-転炉法は原料である鉄鉱石(Fe)を還元材であるコークスとともに高炉へ装入、C濃度が4.5-5.0%程度の溶銑を溶製し、その溶銑を転炉に装入して不純物成分であるC、Si、Pなどを酸化除去する製鋼プロセスである。高炉での溶銑製造時には鉄鉱石の還元などのために溶銑1トンあたり、500kg程度の炭素源を必要とし、約2トン程度のCOガスが発生する。一方、冷鉄源、たとえば、鉄スクラップを原料として溶鋼を製造する場合には、鉄鉱石の還元に必要とされる炭素源が不要となり、鉄スクラップを溶解するために必要なエネルギーを考慮しても、1トンの溶銑を1トンの鉄スクラップに置き換えることで、約1.5トンのCOガス削減につながる。上記のことから、温室効果ガスの排出量の削減と生産活動の維持の両立のためには冷鉄源の使用量を増やしていくことが必要である。 The blast furnace-converter process is a steelmaking process in which iron ore (Fe 2 O 3 ), a raw material, is charged into a blast furnace together with coke, a reducing agent, to produce molten pig iron with a C concentration of about 4.5-5.0%, and the molten pig iron is charged into a converter to oxidize and remove impurities such as C, Si, and P. When producing molten pig iron in a blast furnace, about 500 kg of carbon source is required per ton of molten pig iron for the reduction of iron ore, and about 2 tons of CO 2 gas is generated. On the other hand, when molten steel is produced using a cold iron source, for example, iron scrap, as a raw material, the carbon source required for the reduction of iron ore is not required, and even considering the energy required to melt the iron scrap, replacing 1 ton of molten pig iron with 1 ton of iron scrap leads to a reduction of about 1.5 tons of CO 2 gas. From the above, it is necessary to increase the amount of cold iron source used in order to reduce greenhouse gas emissions and maintain production activities at the same time.

昨今、鉄スクラップ、特に高級鋼製造に不可欠な高品位の鉄スクラップの需給が逼迫していることから、冷鉄源としてスクラップに換えて還元鉄のニーズが高まっている。還元鉄は鉄鉱石を還元して製造され、高炉-転炉法の様に生成した鉄中のC濃度を高位とする必要がない。還元剤として、過剰なC源を使用しない分、鉄1トン当たり約0.2トンのCOガス低減につながる。また、還元剤をC源でなく、水素または天然ガス等の炭化水素系ガスとすることで、更なるCO排出量の低減も可能である。 Recently, the demand for scrap iron, especially high-quality scrap iron essential for the production of high-grade steel, has been tight, and so there is a growing need for reduced iron instead of scrap as a cold iron source. Reduced iron is produced by reducing iron ore, and there is no need to increase the C concentration in the produced iron as in the blast furnace-converter process. Since no excess C source is used as a reducing agent, this leads to a reduction in CO2 gas of about 0.2 tons per ton of iron. In addition, by using a hydrocarbon gas such as hydrogen or natural gas as the reducing agent instead of a C source, it is possible to further reduce CO2 emissions.

還元鉄を使用する際の課題の一つとして、還元鉄にはリンが含まれる点が挙げられる。鉄鋼製品中のリンは熱間脆性などの品質低下を及ぼすため、要求品質に応じたリン濃度まで低減する必要がある。電気炉法で還元鉄を溶解して溶鋼を製造する場合には、還元鉄中のリンの大部分が溶鋼中に入る(復リンともいう)。そのため、現状の還元鉄は鉄鉱石中のリン濃度が低い高品位鉄鉱石(リン濃度約0.01質量%)により製造され、還元鉄としてのリン濃度は約0.02質量%程度である。 One of the issues with using reduced iron is that it contains phosphorus. Phosphorus in steel products can cause quality problems such as hot brittleness, so the phosphorus concentration must be reduced to a level appropriate for the required quality. When reduced iron is melted to produce molten steel using an electric furnace, most of the phosphorus in the reduced iron ends up in the molten steel (also known as rephosphorization). For this reason, reduced iron is currently produced from high-grade iron ore with a low phosphorus concentration (phosphorus concentration of approximately 0.01% by mass), and the phosphorus concentration of the reduced iron is approximately 0.02% by mass.

一方で、リン濃度が低い高品位鉄鉱石の枯渇が予想されており、今後はリン濃度の高い低品位鉄鉱石を使用した還元鉄を原料とした溶鋼製造が求められる。現行の高炉法で使用されている鉄鉱石中のリン濃度は0.05~0.10質量%(還元鉄としてのリン濃度に換算すると0.10~0.15質量%)であり、今後更なるリン濃度増加が予想されている。このリン濃度は前記リン濃度が低い高品位鉄鉱石で製造した還元鉄のリン濃度の5~10倍以上である。このような還元鉄を用いて、鉄鋼製品中のリンによる品質低下を防ぐためには、リン濃度が高い還元鉄を溶解して溶鋼を製造する際にリン除去するか、リン濃度の高い鉄鉱石から還元鉄を製造する際にリン除去する必要がある。このようなリン除去に関し、いくつかの技術が提案されている。 On the other hand, it is predicted that high-grade iron ore with a low phosphorus concentration will be depleted, and in the future, it will be necessary to produce molten steel using reduced iron made from low-grade iron ore with a high phosphorus concentration. The phosphorus concentration in iron ore used in the current blast furnace method is 0.05 to 0.10 mass% (0.10 to 0.15 mass% when converted to the phosphorus concentration as reduced iron), and it is predicted that the phosphorus concentration will increase further in the future. This phosphorus concentration is 5 to 10 times or more than the phosphorus concentration of reduced iron produced from the high-grade iron ore with a low phosphorus concentration. In order to prevent the quality degradation of steel products caused by phosphorus using such reduced iron, it is necessary to remove phosphorus when melting reduced iron with a high phosphorus concentration to produce molten steel, or to remove phosphorus when producing reduced iron from iron ore with a high phosphorus concentration. Several technologies have been proposed for removing phosphorus.

特許文献1には、アーク炉単独で比較的短時間に低濃度まで溶鋼中のリンを除去するための、酸化カルシウムを主成分とし、酸化アルミニウムが5ないし15質量%、酸化鉄が25ないし35質量%および残部が不可避的不純物からなるアーク炉での脱リン精錬用フラックスが提案されている。 Patent Document 1 proposes a flux for dephosphorization refining in an arc furnace, which is composed mainly of calcium oxide, 5 to 15 mass % aluminum oxide, 25 to 35 mass % iron oxide, and the remainder unavoidable impurities, in order to remove phosphorus from molten steel to a low concentration in a relatively short time using only an arc furnace.

また、特許文献2には、鉄鉱石を還元する際に金属鉄が生成しない条件でリンを還元し気化除去を行った後、金属鉄まで還元する方法が提案されている。 Patent Document 2 also proposes a method of reducing iron ore under conditions in which metallic iron is not produced, and then vaporizing and removing phosphorus, and then reducing the phosphorus to metallic iron.

また、特許文献3には、リン含有物質を窒素含有ガスと反応させることでリンを除去する方法が提案されている。 Patent Document 3 also proposes a method for removing phosphorus by reacting a phosphorus-containing substance with a nitrogen-containing gas.

特開平8-120322号公報Japanese Patent Application Laid-Open No. 8-120322 特開2020-20010号公報JP 2020-20010 A 国際公開第2019/131128号International Publication No. 2019/131128

しかしながら、上記従来技術には以下の問題がある。
特許文献1の技術では、スクラップ等のリン濃度が低い鉄源を想定しており、溶鋼中のリン濃度を0.020質量%から0.005質量%まで低減するため、溶鋼量7000gに対してフラックスを350g添加している。還元鉄中のリン濃度が0.15質量%だと仮定すると、リン濃度を鉄鋼製品程度の0.01質量%まで低減するのに必要なフラックス量は、溶鋼1t当たり230kgとなる。したがって、電気炉のアーク炉内でフラックスが占める体積割合が大きくなって溶鋼処理量が減少し、製造効率が悪化するという課題がある。
However, the above-mentioned conventional techniques have the following problems.
The technology of Patent Document 1 assumes that an iron source with a low phosphorus concentration, such as scrap, is used, and 350 g of flux is added per 7,000 g of molten steel to reduce the phosphorus concentration in molten steel from 0.020 mass% to 0.005 mass%. Assuming that the phosphorus concentration in reduced iron is 0.15 mass%, the amount of flux required to reduce the phosphorus concentration to 0.01 mass%, which is the same as that of steel products, is 230 kg per ton of molten steel. Therefore, there is a problem that the volume ratio of the flux in the electric arc furnace increases, reducing the amount of molten steel processing and deteriorating production efficiency.

また、特許文献2の方法は、鉱石中にアパタイトCa(PO)(F,OH)、ストレンジャイトFe(PO)・2(HO)、ウェイベライトAl(PO(F,OH)・5HO等様々な化学形態で存在するリンを還元する必要があるため、脱リン工程での脱リン率が40~60%と低いという課題がある。 Furthermore, the method of Patent Document 2 requires the reduction of phosphorus that exists in the ore in various chemical forms, such as apatite Ca 5 (PO 4 ) (F, OH), strengite Fe (PO 4 ) · 2 (H 2 O), and weaverite Al 3 (PO 4 ) 2 (F, OH) 3 · 5H 2 O, and therefore has the problem that the dephosphorization rate in the dephosphorization process is low at 40 to 60%.

特許文献3の方法は、金属が生成しない温度、酸素分圧での処理であり、リンを除去した後の酸化物を再還元して金属化が必要という課題がある。 The method in Patent Document 3 involves treatment at a temperature and oxygen partial pressure at which metals are not produced, and has the problem that the oxides after phosphorus removal must be re-reduced to metallize them.

本発明は、このような事情に鑑みてなされたものであって、その目的とするところは、湿式処理を行わず、金属製錬用または金属精錬用の主原料もしくは副原料として用いられるリンを含有する金属酸化物から、リンを短時間かつ低コストで効果的に低減させるための、金属酸化物からのリン濃度の低い金属を製造する方法を提案することである。 The present invention was made in consideration of the above circumstances, and its purpose is to propose a method for producing a metal with a low phosphorus concentration from a metal oxide, which is used as a main or auxiliary raw material for metal smelting or refining and contains phosphorus, in a short time and at low cost, without using wet processing, to effectively reduce phosphorus from the metal oxide.

上記課題を有利に解決する本発明にかかる金属の製造方法は、金属製錬用または金属精錬用の主原料もしくは副原料として用いられるリンを含有する金属酸化物を、処理温度T、および酸素分圧PO2,1の調整下で還元性ガスと反応させ、金属を含む固体を生成する金属化処理工程と、金属化処理された前記固体を、温度Tおよび酸素分圧PO2,2の調整下で還元性ガスと反応させ、前記金属中のリンを気相へ除去するリン除去処理工程と、を含み、リン濃度の低い金属を得るものである。 The method for producing a metal according to the present invention, which advantageously solves the above-mentioned problems, includes a metallization process in which a phosphorus-containing metal oxide, which is used as a main or auxiliary raw material for metal smelting or metal refining, is reacted with a reducing gas while adjusting the treatment temperature T1 and the oxygen partial pressure P O2,1 to produce a solid containing a metal, and a phosphorus removal process in which the metallized solid is reacted with a reducing gas while adjusting the temperature T2 and the oxygen partial pressure P O2,2 to remove the phosphorus in the metal into a gas phase, thereby obtaining a metal with a low phosphorus concentration.

なお、本発明にかかる金属の製造方法は、
(ア)前記金属化処理工程では、前記処理温度T(℃)が750℃以上1100℃以下であり、前記酸素分圧PO2,1(atm)が下記の式(1)の条件を満たし、前記リン除去処理工程では、前記処理温度T2(℃)が1000℃以上前記固体の融点Tm(℃)以下であり、前記酸素分圧PO2,2(atm)が下記の式(2)の条件を満たすこと、
(イ)前記リン除去処理工程では、前記酸素分圧PO2,2(atm)が下記の式(3)の条件を、さらに満たすこと、
(ウ)前記金属酸化物が鉄鉱石またはマンガン鉱石であること、
などが好ましい解決手段になり得るものと考えられる。
The method for producing a metal according to the present invention is as follows:
(A) in the metallization treatment step, the treatment temperature T 1 (°C) is 750°C or higher and 1100°C or lower, and the oxygen partial pressure P O2,1 (atm) satisfies the condition of the following formula (1); and in the phosphorus removal treatment step, the treatment temperature T 2 (°C) is 1000°C or higher and the melting point Tm (°C) of the solid or lower, and the oxygen partial pressure P O2,2 (atm) satisfies the condition of the following formula (2);
(A) in the phosphorus removal treatment step, the oxygen partial pressure P O2,2 (atm) further satisfies the condition of the following formula (3);
(c) the metal oxide is iron ore or manganese ore;
This is thought to be a preferable solution.

Figure 0007476872000001
Figure 0007476872000001

Figure 0007476872000002
Figure 0007476872000002

Figure 0007476872000003
Figure 0007476872000003

本発明によれば、金属製錬用または金属精錬用の主原料もしくは副原料として用いられ、リンを含有する鉄鉱石やマンガン鉱石などの金属酸化物に対し、加熱して還元性ガスと反応させ、金属を含む固体を生成する金属化処理工程と、金属化処理された前記固体中のリンを気相へガスとして直接除去するリン除去処理工程と、を含む方法により、短時間かつ低コストで効果的にリン濃度の低い金属を製造することが可能となる。 According to the present invention, a method including a metallization process in which phosphorus-containing metal oxides such as iron ore and manganese ore, which are used as the main or auxiliary raw materials for metal smelting or metal refining, are heated and reacted with a reducing gas to produce a solid containing the metal, and a phosphorus removal process in which the phosphorus in the metallized solid is directly removed as a gas into the gas phase, makes it possible to effectively produce metals with low phosphorus concentrations in a short time and at low cost.

リンをPガスとして気相へ除去する反応(a)、酸化鉄から金属鉄への還元反応(b)についてFeO活量を1としてそれぞれの反応の平衡が成り立つときの温度(T)と酸素分圧(logPO2)の関係を示すグラフである。1 is a graph showing the relationship between temperature (T) and oxygen partial pressure (logP O2 ) when equilibrium is established for the reaction (a) of removing phosphorus into the gas phase as P2 gas , and the reduction reaction (b) of iron oxide to metallic iron, with the FeO activity set to 1. リンをPガスとして気相へ除去する反応(a)、酸化鉄から金属鉄への還元反応(b)についてFeO活量を0.6としてそれぞれの反応の平衡が成り立つときの温度(T)と酸素分圧(logPO2)の関係を示す図である。FIG. 1 shows the relationship between temperature (T) and oxygen partial pressure (logP O2 ) when the equilibrium of each reaction is established for the reaction (a) of removing phosphorus into the gas phase as P2 gas , and the reduction reaction (b) of iron oxide to metallic iron, with the FeO activity set to 0.6. 表2-1~2-4に示す中でリン除去処理工程の処理温度Tが1148℃以上1152℃以下、リン除去処理工程の酸素分圧Po2,2が1.07×10-13以上1.30×10-13以下でほぼ一定の条件である処理No.1~16、処理No.33~51において、金属化処理工程の処理温度T、酸素分圧Po2、1とリン除去率の関係を示す図である。This figure shows the relationship between the treatment temperature T 1 and the oxygen partial pressure P o2,1 in the metallization treatment step and the phosphorus removal rate in Treatment Nos. 1 to 16 and Treatment Nos. 33 to 51, which are under almost constant conditions in which the treatment temperature T 2 in the phosphorus removal treatment step is 1148°C or higher and 1152°C or lower, and the oxygen partial pressure P o2,2 in the phosphorus removal treatment step is 1.07×10 -13 or higher and 1.30×10 -13 or lower, as shown in Tables 2-1 to 2-4. 表2-1~2-4に示す中でリン除去処理工程の処理温度Tが1048℃以上1052℃以下、リン除去処理工程の酸素分圧Po2,2が3.53×10-16以上4.70×10-16以下でほぼ一定の条件である処理No.17~32、処理No.52~70において、金属化処理工程の処理温度T、酸素分圧Po2,1とリン除去率の関係を示す図である。This figure shows the relationship between the treatment temperature T 1 and the oxygen partial pressure P o2,1 in the metallization treatment step and the phosphorus removal rate in Treatment Nos. 17 to 32 and Treatment Nos. 52 to 70, which are conditions in which the treatment temperature T 2 in the phosphorus removal treatment step is 1048° C. or higher and 1052° C. or lower, and the oxygen partial pressure P o2,2 in the phosphorus removal treatment step is 3.53×10 −16 or higher and 4.70×10 −16 or lower, and are almost constant, as shown in Tables 2-1 to 2-4. 表3-1および3-2に示すリン除去処理工程の処理温度Tと酸素分圧PO2、2とがリン除去率に与える影響を示す図である。FIG. 13 is a diagram showing the influence of the treatment temperature T 2 and the oxygen partial pressure P O2, 2 of the phosphorus removal treatment step shown in Tables 3-1 and 3-2 on the phosphorus removal rate.

以下、本発明の実施の形態について具体的に説明する。なお、以下の実施形態は、本発明の技術的思想を具体化するための方法を例示するものであり、構成を下記のものに特定するものでない。すなわち、本発明の技術的思想は、特許請求の範囲に記載された技術的範囲内において、種々の変更を加えることができる。 The following is a detailed description of the embodiments of the present invention. Note that the following embodiments are merely examples of methods for realizing the technical idea of the present invention, and do not limit the configuration to that described below. In other words, the technical idea of the present invention can be modified in various ways within the technical scope described in the claims.

本発明の開発にあたり、発明者らは、金属製錬用または金属精錬用の主原料もしくは副原料として、リン濃度が高く安価な物質に着目し、そうした金属酸化物、たとえば、鉄鉱石やマンガン鉱石から、リン濃度が金属酸化物より低い金属を製造する方法について研究をすすめた。 In developing the present invention, the inventors focused on inexpensive substances with high phosphorus concentrations as main or auxiliary raw materials for metal smelting or refining, and conducted research into a method for producing metals with lower phosphorus concentrations than metal oxides from such metal oxides, such as iron ore or manganese ore.

金属鉄製錬用原料として用いられる鉄鉱石中のリンは、主としてアパタイトCa5(PO4)(F,OH)、ストレンジャイトFe(PO)・2(HO)、ウェイベライトAl(PO(F,OH)・5HO等の酸化物として含有しており、その他にCaOやSiO、MgO、Al、MnO、Mn、FeO、Feなどの金属酸化物が含まれているのが普通である。 The phosphorus in iron ore used as a raw material for smelting metal iron is contained mainly in the form of oxides such as apatite Ca5 ( PO4 )(F,OH), strengite Fe( PO4 ).2( H2O ), and weaverite Al3 ( PO4 ) 2 (F, OH ) 3.5H2O , and usually also contains metal oxides such as CaO , SiO2 , MgO, Al2O3 , MnO, Mn2O3 , FeO, and Fe2O3 .

このように、鉄鉱石は、様々な金属酸化物によって構成されている。ところで、リンは、カルシウム(Ca)および珪素(Si)と比較して酸素との親和力が弱いことから、鉄鉱石を、炭素、珪素、アルミニウムなどを使って還元した場合、鉄鉱石中のリン酸化物は容易に還元されることが知られている。一方で、多くの製鉄用原料中には、鉄がFeOやFeの形態の酸化物(以下、まとめて「FexO」と記す)で含有しており、これらの鉄酸化物は酸素との親和力がリンと同等であることから、鉄鉱石を、炭素や珪素、アルミニウムなどで還元すると、同時にFexOも還元されることになる。 As described above, iron ore is composed of various metal oxides. Since phosphorus has a weaker affinity for oxygen than calcium (Ca) and silicon (Si), it is known that when iron ore is reduced using carbon, silicon, aluminum, etc., the phosphorus oxides in the iron ore are easily reduced. On the other hand, many raw materials for steelmaking contain iron in the form of oxides such as FeO and Fe2O3 (hereinafter collectively referred to as "FexO"), and since these iron oxides have the same affinity for oxygen as phosphorus, when iron ore is reduced using carbon, silicon, aluminum, etc., FexO is also reduced at the same time.

ただ、リンは鉄中への溶解度が高く、とくに還元により生成したリンは、還元により生成した鉄中に溶解し、高リン含有鉄となる。そのため金属鉄が存在する条件では還元により生成したリンが金属鉄に取り込まれてしまうことが課題となる。 However, phosphorus has a high solubility in iron, and in particular the phosphorus produced by reduction dissolves in the iron produced by reduction, resulting in iron with a high phosphorus content. Therefore, in conditions where metallic iron is present, the phosphorus produced by reduction is absorbed into the metallic iron, which poses an issue.

発明者らは、この問題を解決すべく鋭意研究を重ねた結果、鉄などの原料の酸化物を金属まで還元する過程で、原料中の脈石(SiOやAl等の不純物)と必要に応じて添加するCaO源により生成するスラグ相にリンが濃化することに着目し、金属鉄生成段階では鉄中へリンを移行させる事なくスラグ相にリンを濃化し、リンが濃化したスラグ相から効率的にリンを還元して気化除去することにより、金属鉄にリンが取り込まれることを抑制しつつ金属鉄を生成することが可能であることを見出した。この知見は、還元されるリンの挙動が鉄と類似するマンガン鉱石においても、適用できることを確認している。 The inventors have conducted extensive research to solve this problem, and as a result, have focused on the fact that phosphorus is concentrated in the slag phase formed from gangue (impurities such as SiO2 and Al2O3 ) in the raw material and a CaO source added as necessary during the process of reducing oxides of raw materials such as iron to metal, and have found that in the metallic iron production stage, phosphorus is concentrated in the slag phase without transferring to iron, and phosphorus is efficiently reduced and vaporized and removed from the phosphorus-concentrated slag phase, thereby making it possible to produce metallic iron while suppressing phosphorus incorporation into metallic iron. It has been confirmed that this finding can also be applied to manganese ore, in which the behavior of reduced phosphorus is similar to that of iron.

以下、金属酸化物の例として鉄鉱石を例に説明する。すなわち、発明者らは、鉄鉱石中に酸化物として存在するリンを、金属化処理においては下記の化学式1に示す反応(a)は進行させずに鉄鉱石に含まれる鉄酸化物が還元されて金属鉄となる下記の化学式2に示す反応(b)を進行させ、金属鉄相から分離することを実験的検討で確認した。また、リン除去処理においては下記の化学式1に示す反応(a)を進行させ、気相へリン除去することを実験的検討で確認した。 The following describes iron ore as an example of a metal oxide. In other words, the inventors have confirmed through experimental studies that in a metallization process, phosphorus present as an oxide in iron ore is separated from the metallic iron phase by proceeding with reaction (b) shown in chemical formula 2 below, in which the iron oxide contained in the iron ore is reduced to metallic iron, without proceeding with reaction (a) shown in chemical formula 1 below. In addition, the inventors have confirmed through experimental studies that in a phosphorus removal process, reaction (a) shown in chemical formula 1 below is proceeded, and phosphorus is removed into the gas phase.

Figure 0007476872000004
Figure 0007476872000004

Figure 0007476872000005
Figure 0007476872000005

化学式1や2の上記反応(a)や(b)について、平衡が成り立つときの温度と酸素分圧の関係を図1に示す。実線が反応(a)、破線が反応(b)を示す。ここで、P活量を0.001、FeO活量を1、P分圧を0.001atmとした。処理を受ける装入物中に酸化鉄が存在していることを想定し、FeO活量を1とした。なお、図1のグラフは上記条件において、各物質の活量および分圧における温度Tと酸素分圧PO2の平衡関係であり、原料である鉄鉱石の種類や、添加する副原料の種類および量によって変化する。また、鉄以外の金属が主となる場合、たとえばマンガン鉱石では、その主となる金属の還元反応を反応(b)に置き替えることで適用できる。 The relationship between temperature and oxygen partial pressure when equilibrium is established for the above reactions (a) and (b) of chemical formulas 1 and 2 is shown in FIG. 1. The solid line indicates reaction (a), and the dashed line indicates reaction (b). Here, the P2O5 activity is set to 0.001, the FeO activity is set to 1, and the P2 partial pressure is set to 0.001 atm. Assuming that iron oxide is present in the charge to be treated, the FeO activity is set to 1. Note that the graph in FIG. 1 shows the equilibrium relationship between temperature T and oxygen partial pressure P02 at the activity and partial pressure of each substance under the above conditions, and varies depending on the type of iron ore as the raw material and the type and amount of auxiliary raw materials added. In addition, when a metal other than iron is the main component, for example manganese ore, the reduction reaction of the main metal can be replaced with reaction (b) for application.

図1において、反応(a)や(b)それぞれの線より下側の温度と酸素分圧の領域において、反応(a)や(b)がそれぞれ右側に進行する。つまり、金属化処理において反応(a)のリン還元を抑制し、反応(b)による金属鉄の生成が進行するのは、反応(a)の線の上側かつ反応(b)の線の下側であり、ハッチング部である。具体的には酸素分圧を750℃では3.17×10-22atm以上かつ5.49×10-21atm以下、850℃では2.95×10-19atm以上かつ1.66×10-18atm以下、950℃では4.39×10-17atm以上かつ1.09×10-16atm以下、1050℃では1.04×10-15atm以上かつ1.54×10-15atm以下であると好適である。 In Fig. 1, in the temperature and oxygen partial pressure regions below the respective lines for reactions (a) and (b), reactions (a) and (b) proceed to the right, respectively. In other words, in the metallization treatment, the phosphorus reduction in reaction (a) is suppressed, and the production of metallic iron in reaction (b) proceeds above the line for reaction (a) and below the line for reaction (b), which is the hatched area. Specifically, the oxygen partial pressure is preferably 3.17×10 −22 atm or more and 5.49×10 −21 atm or less at 750°C, 2.95×10 −19 atm or more and 1.66×10 −18 atm or less at 850°C, 4.39×10 −17 atm or more and 1.09×10 −16 atm or less at 950°C, and 1.04×10 −15 atm or more and 1.54×10 −15 atm or less at 1050°C.

上記の温度と酸素分圧における金属化処理において、70%以上の高い金属化率と共に、大部分のリンがスラグ相に濃化し、金属鉄中にリンがほとんど存在しないことを確認した。ここで、化学式1および2の上記反応(a)および(b)について、P活量が0.001、FeO活量が0.6、P分圧が0.001atmの場合の温度と酸素分圧の平衡関係を図2に示す。FeO活量を0.6としたのは、金属化処理により装入物中に純粋な酸化鉄がほとんど残っていないことを考慮したことによる。原料や処理条件に応じた適切な値を設定することが好ましい。金属化処理後の鉄鉱石に対し、反応(a)の線の下側となる温度と酸素分圧で処理を行うことで、金属鉄中へのリンの移行を抑制することが可能であった。上述の様に、リンは鉄中への溶解度が高いので、金属鉄の付近で反応(a)によって気化リンが生成しても、金属鉄に吸収されてしまう。しかし、本実施形態では、金属化処理の過程でスラグ相が生成して、凝集・粗大化し、金属鉄との分離が進行する。このため、金属鉄と接触していないスラグ相から金属鉄に吸収されずにリンが気化除去されたと考えられる。また、本実施形態のリン除去処理は還元性ガスを供給して行うものであり、気化したリンは直ちに還元性ガスにより希釈されるので、金属鉄と接触しているスラグ相から生成した気化リンも金属鉄への吸収が起こりにくかったものと考えられる。ただし、リン除去処理の処理温度1000℃未満においてはリン除去がわずかであった。リン酸化物の気化反応を促進するために1000℃以上の高温での処理が好ましい。また1370℃以上においてはリン除去がわずかであり、処理後の金属鉄は、気孔および金属鉄間の間隙が閉塞していたことから、還元性ガスとリン酸化物の接触面積が減少したことが原因と考えられる。示差熱分析法により測定した金属鉄の融点(Tm)は1370℃であり、1300℃では高いリン除去率が得られたため、金属鉄の融点Tm(℃)以下とすることがリン除去のための反応界面積確保の上で好ましいと考えられる。すなわちリンを気相へ除去するためには図2の斜線部においてリン除去処理を行うことが好ましい。 In the metallization treatment at the above temperature and oxygen partial pressure, it was confirmed that the metallization rate was high at 70% or more, most of the phosphorus was concentrated in the slag phase, and almost no phosphorus was present in the metallic iron. Here, for the above reactions (a) and (b) of chemical formulas 1 and 2, the equilibrium relationship between temperature and oxygen partial pressure when the P2O5 activity is 0.001, the FeO activity is 0.6, and the P2 partial pressure is 0.001 atm is shown in Figure 2. The FeO activity is set to 0.6 because it is considered that almost no pure iron oxide remains in the charge after the metallization treatment. It is preferable to set an appropriate value according to the raw material and treatment conditions. By treating the iron ore after the metallization treatment at a temperature and oxygen partial pressure below the line of reaction (a), it was possible to suppress the migration of phosphorus into the metallic iron. As mentioned above, phosphorus has a high solubility in iron, so even if vaporized phosphorus is generated by reaction (a) near the metallic iron, it is absorbed by the metallic iron. However, in this embodiment, a slag phase is generated during the metallization process, which aggregates and coarsens, and separation from metallic iron proceeds. For this reason, it is considered that phosphorus is vaporized and removed from the slag phase that is not in contact with metallic iron without being absorbed by metallic iron. In addition, the phosphorus removal process in this embodiment is performed by supplying a reducing gas, and the vaporized phosphorus is immediately diluted by the reducing gas, so it is considered that the vaporized phosphorus generated from the slag phase in contact with metallic iron is also unlikely to be absorbed by metallic iron. However, phosphorus removal was slight at a treatment temperature of less than 1000°C. In order to promote the vaporization reaction of phosphorus oxide, a treatment at a high temperature of 1000°C or higher is preferable. In addition, phosphorus removal was slight at 1370°C or higher, and it is considered that this is due to the fact that the pores and gaps between the metallic iron in the treated metallic iron were blocked, resulting in a decrease in the contact area between the reducing gas and the phosphorus oxide. The melting point (Tm) of metallic iron measured by differential thermal analysis is 1370°C, and since a high phosphorus removal rate was obtained at 1300°C, it is considered preferable to set the temperature at or below the melting point Tm (°C) of metallic iron in order to ensure a reaction interface area for phosphorus removal. That is, in order to remove phosphorus into the gas phase, it is preferable to perform the phosphorus removal treatment in the shaded area in Figure 2.

なお、前記融点Tmは、固体試料が液体に変化する温度のことであり、下記第1~第3のいずれかの方法で決定することが簡易的であり好ましいが、これらの方法に限定するものではない。
第1の方法は、るつぼ等の容器に固体試料を装入し、対象とするガス雰囲気下において、電気抵抗炉などにより毎分5℃、望ましくは毎分1℃以下で昇温しながら容器内の試料を連続的に観察し、固体試料の粒同士の隙間が消失し、表面に平滑面が生じた温度を融点とする方法である。
第2の方法は、対象とするガス雰囲気下において、示差熱分析法により毎分5℃、望ましくは毎分1℃以下で昇温して測定した際の、吸熱ピークの極小点の温度を融点とする方法である。ここで、吸熱ピークが複数生じる場合、それぞれの吸熱ピークが生じた温度で測定を止めて、測定試料の外観を観察し、固体試料の粒同士の隙間が消失し、表面に平滑面が生じた温度の中で最も低温の吸熱ピークの極小点の温度を融点とする方法である。
第3の方法は、電子計算機の熱力学計算ソフトを用い、試料組成を入力して温度を変化させて液相率を計算し、計算液相率が95%を超える温度を融点とする方法である。
The melting point Tm is the temperature at which a solid sample changes into a liquid, and is preferably determined by any one of the following first to third methods because it is easy to do so, but is not limited to these methods.
The first method is to place a solid sample in a container such as a crucible, and in a target gas atmosphere, use an electric resistance furnace or the like to raise the temperature at a rate of 5°C per minute, preferably 1°C per minute or less, while continuously observing the sample in the container, and determine the melting point as the temperature at which the gaps between the grains of the solid sample disappear and a smooth surface appears on the surface.
The second method is to measure the melting point by increasing the temperature by 5° C. per minute, preferably 1° C. per minute or less, using differential thermal analysis in a target gas atmosphere, and to determine the temperature of the minimum point of the endothermic peak. When multiple endothermic peaks are generated, the measurement is stopped at the temperature at which each endothermic peak occurs, the appearance of the measured sample is observed, and the melting point is determined to be the lowest temperature of the minimum point of the endothermic peak at which the gaps between the grains of the solid sample disappear and a smooth surface appears on the surface.
The third method is to use a thermodynamic calculation software of a computer, input the sample composition, change the temperature to calculate the liquid phase ratio, and define the temperature at which the calculated liquid phase ratio exceeds 95% as the melting point.

還元処理のための還元剤としては、還元性ガスを用いる。固体炭素や金属Al、金属Si等の固体還元剤は極めて強い還元能力を有しているため、処理温度と酸素分圧を本実施形態で定める適正な条件とすることが困難である。一方で、還元性ガスであれば、ガス成分を調整することで、上述の処理温度と酸素分圧を適正条件とすることが容易である。さらに、気孔率および比表面積が増大した鉄鉱石を効率的に還元することが可能となり、短時間での処理が期待される。還元性ガスのガス種は特に限定されず、CO、H、CH等の還元成分を少なくとも1種以上含むガスであれば使用することが出来る。また、還元性ガスは天然に採掘されるガスに限らず、高炉炉頂ガスやコークス炉ガス等の副生ガス、および水の電気分解により生成したHガス等を、単独または混合して用いることが可能である。また、上記例では、鉄鉱石を用い、金属鉄を生成することを例に説明したが、マンガン鉱石などにも適用可能である。 A reducing gas is used as a reducing agent for the reduction treatment. Since solid reducing agents such as solid carbon, metal Al, and metal Si have extremely strong reducing ability, it is difficult to set the treatment temperature and oxygen partial pressure to the appropriate conditions defined in this embodiment. On the other hand, if a reducing gas is used, it is easy to set the above-mentioned treatment temperature and oxygen partial pressure to the appropriate conditions by adjusting the gas components. Furthermore, it is possible to efficiently reduce iron ore with increased porosity and specific surface area, and treatment in a short time is expected. The type of reducing gas is not particularly limited, and any gas containing at least one reducing component such as CO, H 2 , and CH 4 can be used. In addition, the reducing gas is not limited to naturally mined gas, and by-product gases such as blast furnace top gas and coke oven gas, and H 2 gas generated by electrolysis of water, etc., can be used alone or in mixture. In the above example, the example of generating metallic iron using iron ore has been described, but it is also applicable to manganese ore, etc.

(実施例1)
処理に用いた鉄鉱石の組成を表1に示す。示差熱分析法により測定した金属鉄の融点(Tm)は1370℃である。5トン/hr規模の回転炉床炉に鉄鉱石を装入し、加熱バーナーによって鉄鉱石を加熱した。このとき加熱バーナーに供給する炭化水素、酸素ガスの流量を制御して処理温度を調整し、炭化水素と酸素の比および流量を制御することにより酸素分圧を調整して金属化処理を実施し、金属鉄を生成した。装入から排出までの時間が90分となるように炉床の移動速度を設定した。次いで、5トン/hr規模の別の回転炉床炉に金属化処理後の金属鉄を装入し、加熱バーナーによって金属鉄を加熱した。このとき加熱バーナーに供給する炭化水素、酸素ガスの流量を制御して処理温度を調整し、炭化水素と酸素の比および流量を制御することにより酸素分圧を調整してリン除去処理を実施した。装入から排出までの時間が90分となるように炉床の移動速度を設定した。金属化処理、リン除去処理の処理温度、処理ガス組成はそれぞれの装入から処理時間の2分の1の時点で存在する箇所での温度測定、ガス組成分析を行って調製した。燃焼反応は下記化学式3に示す反応(c)によって代表され、酸素分圧はガス組成分析の測定値から下記式(4)および(5)より算出した。式(4)は反応(c)のギブズ自由エネルギーΔG°を表し、式(5)は反応(c)の平衡定数Kを表す。式(4)および式(5)中、Tは測定した温度(K)、Rは気体定数(cal/(K・mol))、PCOおよびPCO2はガス組成分析におけるCOおよびCOの分圧である。
Example 1
The composition of the iron ore used in the treatment is shown in Table 1. The melting point (Tm) of metallic iron measured by differential thermal analysis is 1370°C. The iron ore was charged into a 5 ton/hr rotary hearth furnace and heated by a heating burner. At this time, the flow rates of the hydrocarbon and oxygen gas supplied to the heating burner were controlled to adjust the treatment temperature, and the ratio and flow rate of the hydrocarbon and oxygen were controlled to adjust the oxygen partial pressure to perform the metallization treatment and produce metallic iron. The moving speed of the hearth was set so that the time from charging to discharging was 90 minutes. Next, the metallic iron after the metallization treatment was charged into another 5 ton/hr rotary hearth furnace and heated by a heating burner. At this time, the flow rates of the hydrocarbon and oxygen gas supplied to the heating burner were controlled to adjust the treatment temperature, and the ratio and flow rate of the hydrocarbon and oxygen were controlled to adjust the oxygen partial pressure to perform the phosphorus removal treatment. The moving speed of the hearth was set so that the time from charging to discharging was 90 minutes. The treatment temperature and treatment gas composition of the metallization treatment and phosphorus removal treatment were adjusted by measuring the temperature at the point where the gas was present at half the treatment time from the time of charging and analyzing the gas composition. The combustion reaction is represented by reaction (c) shown in the following chemical formula 3, and the oxygen partial pressure was calculated from the measured value of the gas composition analysis by the following formulas (4) and (5). Formula (4) represents the Gibbs free energy ΔG° of reaction (c), and formula (5) represents the equilibrium constant K of reaction (c). In formulas (4) and (5), T is the measured temperature (K), R is the gas constant (cal/(K·mol)), and P CO and P CO2 are the partial pressures of CO and CO2 in the gas composition analysis.

Figure 0007476872000006
Figure 0007476872000006

Figure 0007476872000007
Figure 0007476872000007

Figure 0007476872000008
Figure 0007476872000008

金属化処理工程では、温度およびガス組成条件を変更して、雰囲気の酸素分圧を制御した。リン除去処理工程では、処理温度T=1150℃程度、PCO/PCO2=4程度、および、処理温度T=1050℃程度、PCO/PCO2=11.4程度の2水準を選んだ。各処理条件を表2-1~2-4に記載する。質量基準の百分率で表す、リン除去率ΔP=[1-{(リン除去処理後P濃度)/(リン除去処理後T.Fe濃度)}/{(リン除去処理前P濃度)/(リン除去処理前T.Fe濃度)}]×100(%)および金属化率=(リン除去処理後M.Fe濃度)/(リン除去処理後T.Fe濃度)×100(%)をそれぞれ表2-1~2-4に併記する。ここで、T.Fe濃度は試料中の全鉄濃度の分析値であり、M.Fe濃度は試料中の金属鉄濃度の分析値である。 In the metallization process, the temperature and gas composition conditions were changed to control the oxygen partial pressure of the atmosphere. In the phosphorus removal process, two levels were selected: a treatment temperature T 2 = about 1150°C, P CO /P CO2 = about 4, and a treatment temperature T 2 = about 1050°C, P CO /P CO2 = about 11.4. The treatment conditions are shown in Tables 2-1 to 2-4. The phosphorus removal rate ΔP = [1 - {(P concentration after phosphorus removal process) / (T.Fe concentration after phosphorus removal process)} / {(P concentration before phosphorus removal process) / (T.Fe concentration before phosphorus removal process)}] x 100 (%) and the metallization rate = (M.Fe concentration after phosphorus removal process) / (T.Fe concentration after phosphorus removal process) x 100 (%), expressed as a percentage based on mass, are also shown in Tables 2-1 to 2-4. Here, the T.Fe concentration is the analytical value of the total iron concentration in the sample, and the M.Fe concentration is the analytical value of the total iron concentration in the sample. The Fe concentration is the analytical value of the metallic iron concentration in the sample.

Figure 0007476872000009
Figure 0007476872000009

Figure 0007476872000010
Figure 0007476872000010

Figure 0007476872000011
Figure 0007476872000011

Figure 0007476872000012
Figure 0007476872000012

表2-1~2-3に示す、リン除去処理条件が処理温度T=1148℃~1152℃の範囲および酸素分圧logPO2,2(atm)=-13.0~-12.9の範囲にある処理No.1~16および33~51について、金属化処理の温度T、酸素分圧PO2,1とリン除去率ΔPの関係を図3に図示した。図3中に、処理No.1~16を●の記号で、処理No.33~51を×の記号でプロットした。 For Process Nos. 1 to 16 and 33 to 51, whose phosphorus removal treatment conditions are in the range of process temperature T2 = 1148°C to 1152°C and oxygen partial pressure logP O2,2 (atm) = -13.0 to -12.9 as shown in Tables 2-1 to 2-3, the relationship between the metallization treatment temperature T1 , oxygen partial pressure P O2,1 , and the phosphorus removal rate ΔP is shown in Figure 3. In Figure 3, Process Nos. 1 to 16 are plotted with the symbol ●, and Process Nos. 33 to 51 are plotted with the symbol ×.

表2-1~2-4に示す、リン除去処理条件が処理温度T=1048℃~1052℃の範囲および酸素分圧logPO2,2(atm)=-15.4~-15.3の範囲にある処理No.17~32および52~70について、金属化処理の温度T、酸素分圧PO2,1とリン除去率ΔPの関係を図4に図示した。図4中に、処理No.17~32を●の記号で、処理No.52~70を×の記号でプロットした。 For Process Nos. 17 to 32 and 52 to 70, which are shown in Tables 2-1 to 2-4 and have phosphorus removal conditions in the range of process temperature T 2 =1048°C to 1052°C and oxygen partial pressure logP O2,2 (atm) =-15.4 to -15.3, the relationship between the metallization process temperature T 1 , oxygen partial pressure P O2,1 and phosphorus removal rate ΔP is shown in Figure 4. In Figure 4, Process Nos. 17 to 32 are plotted with the symbol ●, and Process Nos. 52 to 70 are plotted with the symbol ×.

図1の検討、図3および4の結果から金属化処理工程における、処理温度Tが750℃以上1100℃以下の範囲、かつ、処理温度T、酸素分圧PO2,1が下記式(1a)および(1b)を満たすときに72%以上の高いリン除去率ΔPおよび85%以上の高い金属化率が得られていることがわかる。
logPO2,1≧-2.49×10-5 +0.0861T-84.1 (1a)
logPO2,1≦-2.08×10-5 +0.0720T-72.4 (1b)
From the examination of FIG. 1 and the results of FIGS. 3 and 4, it can be seen that when the treatment temperature T1 in the metallization treatment step is in the range of 750° C. or higher and 1100° C. or lower, and the treatment temperature T1 and the oxygen partial pressure P O2,1 satisfy the following formulas (1a) and (1b), a high phosphorus removal rate ΔP of 72% or higher and a high metallization rate of 85% or higher are obtained.
logP O2,1 ≧−2.49×10 −5 T 1 2 +0.0861 T 1 −84.1 (1a)
logP O2,1 −2.08× 10−5 T12 + 0.0720T1−72.4 (1b)

表2-1~2-4において、金属化処理工程の評価欄において、Aは処理温度Tが750℃以上1100℃以下の範囲にあり、酸素分圧PO2,1が上記式(1a)および式(1b)を満たすもの、Bは処理温度T1が750℃以上1100℃以下の範囲にあり、酸素分圧PO2,1が上記式(1a)および式(1b)のいずれかを満たさないもの、Cは処理温度Tが750℃以上1100℃以下の範囲になく、酸素分圧PO2,1が上記式(1a)および式(1b)を満たすもの、Dは処理温度T1が750℃以上1100℃以下の範囲になく、酸素分圧PO2,1が上記式(1a)および式(1b)のいずれかを満たさないものを表す。リン除去処理工程の評価については後述する。 In Tables 2-1 to 2-4, in the evaluation column for the metallization process, A indicates that the treatment temperature T1 is in the range of 750° C. or more and 1100° C. or less, and the oxygen partial pressure P O2,1 satisfies the above formulas (1a) and (1b), B indicates that the treatment temperature T1 is in the range of 750° C. or more and 1100° C. or less, and the oxygen partial pressure P O2,1 does not satisfy either of the above formulas (1a) and (1b), C indicates that the treatment temperature T1 is not in the range of 750° C. or more and 1100° C. or less, and the oxygen partial pressure P O2,1 satisfies either of the above formulas (1a) and (1b), and D indicates that the treatment temperature T1 is not in the range of 750° C. or more and 1100° C. or less, and the oxygen partial pressure P O2,1 does not satisfy either of the above formulas (1a) and (1b). The evaluation of the phosphorus removal process will be described later.

表2-1~2-2に示す処理No.1~32は、金属化処理工程の評価およびリン除去処理工程の評価がいずれもAであり、72%以上の高いリン除去率ΔPおよび85%以上の高い金属化率が得られている。 Treatment Nos. 1 to 32 shown in Tables 2-1 to 2-2 were both rated A for the metallization process and the phosphorus removal process, and achieved a high phosphorus removal rate ΔP of 72% or more and a high metallization rate of 85% or more.

(実施例2)
次に、実施例1と同様の原料および設備を用い、リン除去処理工程では、温度およびガス組成条件を変更して、雰囲気の酸素分圧を制御した。金属化処理工程では、処理温度T=900℃程度、PCO/PCO2=3程度のほぼ一定とした。各処理条件を表3-1~3-2に記載し、実施例1と同様、リン除去率ΔPおよび金属化率を併記した。
Example 2
Next, using the same raw materials and equipment as in Example 1, the temperature and gas composition conditions were changed to control the oxygen partial pressure of the atmosphere in the phosphorus removal treatment step. In the metallization treatment step, the treatment temperature T 1 was approximately constant at about 900° C., and P CO /P CO2 was approximately 3. The treatment conditions are shown in Tables 3-1 to 3-2, and the phosphorus removal rate ΔP and metallization rate are also shown as in Example 1.

Figure 0007476872000013
Figure 0007476872000013

Figure 0007476872000014
Figure 0007476872000014

表3-1および3-2の結果を、リン除去処理の温度T、酸素分圧PO2,2とリン除去率ΔPの関係で整理し、図5に図示した。図5中の記号◆はリン除去率ΔPが80%以上かつ金属化率が85%以上の処理No.71,72,74,75,77,78,80,81,83,84,86,87、89,90,92,93を表す。図5中の記号■はリン除去率ΔPが72%以上80%未満かつ金属化率が85%以上の処理No.73、76、79、82、85、88、91、94を表す。図5中でその他の条件を記号×とした。 The results of Tables 3-1 and 3-2 were organized in terms of the relationship between the phosphorus removal treatment temperature T 2 , oxygen partial pressure P O2,2 , and the phosphorus removal rate ΔP, and are shown in Figure 5. The symbol ◆ in Figure 5 represents treatment Nos. 71, 72, 74, 75, 77, 78, 80, 81, 83, 84, 86, 87, 89, 90, 92, and 93, which had a phosphorus removal rate ΔP of 80% or more and a metallization rate of 85% or more. The symbol ■ in Figure 5 represents treatment Nos. 73, 76, 79, 82, 85, 88, 91, and 94, which had a phosphorus removal rate ΔP of 72% or more but less than 80% and a metallization rate of 85% or more. Other conditions in Figure 5 are marked with the symbol ×.

表3-1および表3-2の処理No.71~94の結果ならびに図5から明らかなように、リン除去処理工程では、処理温度Tが1000℃以上金属の融点T以下の範囲で、Tおよび酸素分圧PO2,2が下記式(2)の関係を満たすときに、72%以上のリン除去率ΔPおよび85%以上の金属化率が得られることがわかる。
logPO2,2≦-1.05×10-5 +0.0408T-45.5 (2)
As is apparent from the results of Treatment Nos. 71 to 94 in Tables 3-1 and 3-2 and Fig. 5, in the phosphorus removal treatment step, when the treatment temperature T2 is in the range of 1000°C or higher and the melting point Tm of the metal or lower, and T2 and the oxygen partial pressure P02,2 satisfy the relationship of the following formula (2), a phosphorus removal rate ΔP of 72% or higher and a metallization rate of 85% or higher can be obtained.
logP O2,2 ≦−1.05× 10−5 T22 + 0.0408T1−45.5 (2)

さらに、上記条件に加えて、リン除去処理工程で、処理温度Tおよび酸素分圧PO2,2が下記式(3)の関係を満たすときに、80%以上のリン除去率ΔPおよび85%以上の金属化率が得られることがわかる。
logPO2,2≧-0.823×10-5 +0.0339T-41.4 (3)
Furthermore, in addition to the above conditions, it can be seen that when the treatment temperature T2 and the oxygen partial pressure P02,2 in the phosphorus removal treatment step satisfy the relationship of the following formula (3), a phosphorus removal rate ΔP of 80% or more and a metallization rate of 85% or more can be obtained.
logP O2,2 ≧−0.823× 10−5 T22 + 0.0339T2−41.4 (3)

なお、リン除去処理工程の評価欄において、Aは処理温度Tが1000℃以上金属の融点T以下の範囲にあり、酸素分圧PO2,2が上記式(2)および(3)を満たすもの、Bは処理温度Tが1000℃以上金属の融点T以下の範囲にあり、酸素分圧PO2,2が上記式(2)を満たし、上記式(3)を満たさないもの、Cは処理温度Tが1000℃以上金属の融点T以下の範囲になく、酸素分圧PO2,2が上記式(2)および(3)を満たすもの、Dは処理温度Tが1000℃以上金属の融点T以下の範囲にあり、酸素分圧PO2,2が上記式(2)を満たさないもの、Eは処理温度Tが1000℃以上金属の融点T以下の範囲になく、酸素分圧PO2,2が上記式(2)を満たし、上記式(3)を満たさないもの、を表す。 In the evaluation column for the phosphorus removal process, A denotes a treatment temperature T2 in the range of 1000° C. or higher and the melting point Tm of the metal or lower, and the oxygen partial pressure P O2,2 satisfies the above formulas (2) and (3); B denotes a treatment temperature T2 in the range of 1000° C. or higher and the melting point Tm of the metal or lower, and the oxygen partial pressure P O2,2 satisfies the above formula (2) but does not satisfy the above formula (3); C denotes a treatment temperature T2 not in the range of 1000° C. or higher and the melting point Tm of the metal or lower, and the oxygen partial pressure P O2,2 satisfies the above formulas (2) and (3); D denotes a treatment temperature T2 in the range of 1000° C. or higher and the melting point Tm of the metal or lower, and the oxygen partial pressure P O2,2 does not satisfy the above formula (2); and E denotes a treatment temperature T2 not in the range of 1000° C. or higher and the melting point Tm of the metal or lower, and the oxygen partial pressure P O2,2 satisfies the above formula (2) but does not satisfy the above formula (3).

処理No.95は、処理温度Tが1000℃より低く、リン除去率ΔPは2%であった。リン除去反応が進行するために必要な温度に達していなかったと考えられる。処理No.96~103は、酸素分圧PO2,2が上記式(2)を満たしておらず、リン除去率ΔPは5%以下であった。リン酸化物を還元するために十分な低い酸素分圧となっていなかったと考えられる。処理No.104および105は、処理温度Tが別途測定した金属鉄の融点Tm~1370℃より高く、リン除去率ΔPは5%以下であった。金属鉄が溶融した結果、気孔が閉塞し、気相へ除去されるリンが減少したと考えられる。 In treatment No. 95, the treatment temperature T2 was lower than 1000°C, and the phosphorus removal rate ΔP was 2%. It is believed that the temperature required for the phosphorus removal reaction to proceed was not reached. In treatments No. 96 to 103, the oxygen partial pressure P O2,2 did not satisfy the above formula (2), and the phosphorus removal rate ΔP was 5% or less. It is believed that the oxygen partial pressure was not low enough to reduce phosphorus oxides. In treatments No. 104 and 105, the treatment temperature T2 was higher than the melting point Tm of metallic iron, which was measured separately, 1370°C, and the phosphorus removal rate ΔP was 5% or less. It is believed that the metallic iron melted, causing the pores to be blocked, and the amount of phosphorus removed to the gas phase decreased.

本発明の金属の製造方法は、短時間かつ低コストで効果的にリン濃度の低い金属を製造することができるので、特に鉄鋼製錬・精錬に適用して、炭酸ガス排出量抑制に寄与し、産業上有用である。
The metal production method of the present invention can effectively produce metals with low phosphorus concentrations in a short time and at low cost, and is therefore industrially useful, particularly when applied to steel smelting and refining, and contributes to the reduction of carbon dioxide emissions.

Claims (4)

金属製錬用または金属精錬用の主原料もしくは副原料として用いられる、リンを含有する金属酸化物を、処理温度T、および酸素分圧PO2,1の調整下で還元性ガスと反応させ、金属を含む固体を生成する金属化処理工程と、
金属化処理された前記固体を、温度Tおよび酸素分圧PO2,2の調整下で還元性ガスと反応させ、前記固体中のリンを気相へ除去するリン除去処理工程と、
を含み、リン濃度の低い金属を得る、金属の製造方法。
a metallization process in which a phosphorus-containing metal oxide, which is used as a main or auxiliary raw material for metal smelting or metal refining, is reacted with a reducing gas under the control of a treatment temperature T 1 and an oxygen partial pressure P O2,1 to produce a solid containing a metal;
a phosphorus removal process in which the metallized solid is reacted with a reducing gas under control of a temperature T2 and an oxygen partial pressure P02,2 to remove phosphorus from the solid into a gas phase;
The method for producing a metal includes the steps of:
前記金属化処理工程では、前記処理温度T(℃)が750℃以上1100℃以下であり、前記酸素分圧PO2,1(atm)が下記の式(1)の条件を満たし、
前記リン除去処理工程では、前記処理温度T2(℃)が1000℃以上前記固体の融点Tm(℃)以下であり、前記酸素分圧PO2,2(atm)が下記の式(2)の条件を満たす、請求項1に記載の金属の製造方法。
Figure 0007476872000015
Figure 0007476872000016
In the metallization treatment step, the treatment temperature T 1 (° C.) is 750° C. or higher and 1100° C. or lower, and the oxygen partial pressure P O2,1 (atm) satisfies the condition of the following formula (1):
2. The method for producing a metal according to claim 1, wherein in the phosphorus removal treatment step, the treatment temperature T2 (°C) is 1000°C or higher and the melting point Tm (°C) of the solid or lower, and the oxygen partial pressure P02,2 (atm) satisfies the condition of the following formula (2).
Figure 0007476872000015
Figure 0007476872000016
前記リン除去処理工程では、前記酸素分圧PO2,2(atm)が下記の式(3)の条件を、さらに満たす請求項2に記載の金属の製造方法。
Figure 0007476872000017
The method for producing a metal according to claim 2 , wherein in the phosphorus removal treatment step, the oxygen partial pressure P O2,2 (atm) further satisfies the condition of the following formula (3).
Figure 0007476872000017
前記金属酸化物が鉄鉱石またはマンガン鉱石である請求項1~3のいずれか1項に記載の金属の製造方法。
The method for producing a metal according to any one of claims 1 to 3, wherein the metal oxide is iron ore or manganese ore.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010189762A (en) 2009-01-23 2010-09-02 Kobe Steel Ltd Process for manufacturing granular iron
CN104451016A (en) 2014-11-25 2015-03-25 北京神雾环境能源科技集团股份有限公司 Method for separating metal iron from phosphorus containing iron ore
JP2020020010A (en) 2018-08-02 2020-02-06 日本製鉄株式会社 Reduction method of high-phosphorus iron ore

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010189762A (en) 2009-01-23 2010-09-02 Kobe Steel Ltd Process for manufacturing granular iron
CN104451016A (en) 2014-11-25 2015-03-25 北京神雾环境能源科技集团股份有限公司 Method for separating metal iron from phosphorus containing iron ore
JP2020020010A (en) 2018-08-02 2020-02-06 日本製鉄株式会社 Reduction method of high-phosphorus iron ore

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