Decarburization Of Iron Research Articles

Chemical reactions during iron reduction from oxides in carbon monoxide environment

The chemical process appearing at thermal contact of hematite with carbon monoxide was modeled using TERRA software package. In this case, the molar ratio of CO/Fe 2 O 3 components varied in the range of 1 – 15, and the process temperature – in the range of 25 – 1500 °C. Carbon monoxide at normal temperature decomposes almost completely to form carbon and carbon dioxide (the Bell-Boudoir reaction). When the process temperature increases, this carbon consistently participates in formation of the phases of magnetite, iron and cementite, and carbon dioxide participates in vustite formation and in iron decarburization. The carbon monoxide does not directly participate as a reducing reagent in local chemical reactions of this process.

Regulating the nitrogen content in steel and alloys

The behavior of nitrogen in the decarburization of iron and alloy melts is analyzed. In laboratory conditions, nitriding from the gas phase is studied, as well as the removal of nitrogen from alloy (Cr-Ni and Cr-Mn) melts. Parameters are established for the regulation of the nitrogen content in steel in gas-oxygen refining and ladle treatment. The results permit the development of guidelines for the alloying of steel with nitrogen and for regulation of the nitrogen content by means of the gas phase (N2, Ar) in smelting and ladle treatment.

Glimmers of research in metallurgy

Directions of research in metallurgy, as well as in general, used to be strongly influenced by national or local needs and circumstances. The availability of raw materials and energy were the key factors for metallurgical industry, especially in such geographically eccentric areas as Finland. In basic research, however, the role of the international context has been quite strong through centuries. In the current globalization scene, the role of R&D is further emphasized for the success of the metallurgical industry. International networks and cooperation take place both in basic research and in the development of new industrial innovations. In this contribution, some personal experiences in metallurgical research during the last 40 years are reviewed and discussed considering the current and future perspectives. As examples, studies on iron decarburization, non‐stoichiometric compounds, oxide sulfation, slag chemistry in steel, copper and ferroalloys processes, injection metallurgy and inclusion control, gas bubble bursting, thermal plasma synthesis, continuous casting and solidification are briefly discussed.

CO-CO<SUB>2</SUB>, H<SUB>2</SUB>-H<SUB>2</SUB>O混合ガスによる高炭素溶鉄の脱炭および脱炭速度におよぼす硫黄の影響

Decarburization of iron with a high carbon content is one of the main reactions in the coal gasification process using molten iron bath, where O2 or H2O is used as an oxidizing agent. In this process, sulphur accumulation through direct dissolution of coal into the melt may influence the decarburization rate.In the present study, high carbon iron was decarburized by blowing H2-H2O and CO-CO2 gas mixtures on the metal surface in the temperature range between 1673 and 1873 K. Influence of sulphur on the rate of decarburization was also studied.The results were summarized as follows.(1) The following non-dimensional correlation was found in the regime of mass transfer control in the gas phase.(This article is not displayable. Please see full text pdf.) (2) When sulphur was added, a negative deviation from the above relationship was observed. This might be due to the mixed control of mass transfer in the gas phase and the chemical reaction on the iron surface.Much more deviation for CO-CO2 than for H2-H2O was observed. It was attributed to the fact that the apparent rate constant for dissociative chemisorption, kC, of H2O was much greater than that of CO2. The ratio between the rate constants was estimated to be more than ten at about 0.4 mass%S.(3) The rate constant for dissociative chemisorption, kC0, of H2O was found to be 30-80 times as large as that for CO2 on the basis of the sulphur blockage mechanism by chemisorbed sulphur. It was concluded that this difference in the kC0-values may cause the stronger influence on the rate of decarburization with CO-CO2 by the chemisorbed sulphur.

Kinetics of carburization and decarburization of iron and iron-10% nickel in CH 4H 2 mixtures

Kinetics of carburization and decarburization of iron and iron-10% nickel in CH 4H 2 mixtures

The use of isotope exchange reactions for the study of heterogenous reaction kinetics

The oxygen transfer to metals and oxides was studied in CO2-CO and H2O-H2 mixtures at 700° – 1000°C with the aid of isotope exchange reactions. Rate equations, rate coefficients and activation energies are obtained for the reactions CO2 ⇋ CO + O (ad) and H2O ⇋ H (ad) + OH (ad). The dependences on the thermodynamic oxygen activity on and in the solid were determined in equilibrium of solid and gas atmosphere. The kinetic data from the isotope exchange studies can be used for the treatment and description of complex heterogeneous reactions in which oxygen transfer from CO2 or H2O occurs as a partial reaction step, for example decarburization of iron, oxidation of iron to wustite and reduction of magnetite, watergas shift reaction and carbon gasification. Résumé Le transfert d'oxygène vers les Métaux et les oxydes a été étudié dans les mélanges CO2CO et H2O-H2 entre 700° et 10000°C, à l'aide de réactions d'échange d'isotopes. Les équations de vitesse, les coefficients de vitesse et les énergies d'activation ont été obtenus pour les réactions CO2 ↔ CO + O(ad) et H2O ↔ H(ad) + OH(ad). A l'équilibre entre Ie solide et l'atmosphère gazeuse, on a déterminé les activités thermodynamiques de l'oxygè ne. Les résu1tats cinétiques de l'echange d'isotopes étudié peuvent être utilisés pour le traitement et la description de réactions complexes hétérogènes dans lesquelles le transfert d'oxygè ne de CO2 ou H2O se produit comme une étape de réaction partielle, par exemple la décarburation du fer, l'oxydation du fer en wustite, la réduction de la magnétite, la réaction de déplacement par le gaz à l'eau, et la gazéification du carbone

鉄鋼の脱炭について（第3報）鉄の微量炭素除去とガス放出

鉄鋼の脱炭について（第3報）鉄の微量炭素除去とガス放出

鉄鋼の脱炭について（第2報）

鉄鋼の脱炭について（第2報）