Equilibrium kinetics of manganese-ore carbon-reduction between molten steel and slag

The smelting process of high‐manganese pig iron is studied to determine ways to efficiently utilize the by‐product of manganese‐rich slag. This process consists of two stages: 1) demanganese and carbon retention and 2) decarbonization and dephosphorization. In the first stage, oxygen is supplied at 0.5–2.0 Nm3 t−1 min−1. The temperature is controlled between 1300 and 1400 °C by adding iron ore to the molten bath. Ultimately, high‐manganese slag, which contains more than 50% manganese oxide and semisteel with 3.2% carbon, is produced. In the second stage, oxygen is supplied at 2.0−5.0 Nm3 t−1 min−1 and slag‐forming materials are added to the molten bath for the dephosphorization and desulfurization of the hot metal. Consequently, the iron oxide, manganese oxide, and silicon oxide contents of the high‐manganese slag and the carbon, manganese, phosphorus, and sulfur contents of the semisteel are 10.8–15.3%, 70–77%, and 3–7%, and 3.2–4.2%, 0.3–1.0%, 0.12–0.22%, and 0.01–0.024%, respectively. The main mineral phases of high‐manganese slag, 2MnO·SiO2 and FeO·MnO·SiO2, are suitable for the preparation of high‐carbon ferromanganese raw materials. After further smelting, clean molten steel containing 0.03−0.08%, 0.08−0.20%, 0.005−0.02%, and 0.01−0.024% carbon, manganese, phosphorus, and sulfur, respectively, is obtained.

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“…The activity coefficients of MnO, Mn, C, and Si were retrieved from the literature. [ 23–25 ]

log L^{'} _{\text{Mn}} = - 11.42 + \frac{2511}{T} + \frac{1500.63}{T} - log \left[\right. \% C \left]\right.

…”

Section: Resultsmentioning

confidence: 99%

“…[%C] is the carbon content; r MnO is the activity coefficient of MnO in slag; f Mn is the activity coefficient of manganese; p CO is the The activity coefficients of MnO, Mn, C, and Si were retrieved from the literature. [23][24][25] log…”

Section: Factors Affecting Manganese Distribution Ratio and Decarburi...mentioning

confidence: 99%

Study on Efficient Use of High‐Manganese Pig Iron

Zhao

Yang

et al. 2023

steel research int.

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“…Figure 4 the Cr 2 O 3 content in the slag increases from 1 wt-% to 5 wt-%, the proportion of liquid phase of the slag decreases from 87.31 to 78.56%. One of the advantages of semi-steel smelting is that manganese ore can be added to replace part of the ferromanganese added in the subsequent alloying process, thus greatly reducing the alloying cost [16,17]. The influence of MnO content on the proportion of liquid phase of CaO-SiO 2 -FeO-MgO-MnO-Cr 2 O 3 slag system at 1873K is shown in Figure 5.…”

Section: Resultsmentioning

confidence: 99%

Slag formation path in converter smelting process of semi-steel containing chromium

Diao

Liu

et al. 2020

Ironmaking & Steelmaking

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Aiming at the high-efficiency utilization of vanadium-titanium magnetite with high chromium content, a slag formation path in the converter smelting process of semi-steel containing chromium was proposed. The influences of MnO and Cr 2 O 3 on the melting characteristics of converter slag were calculated through FactSage. The effects of components and temperature on the equilibrium distribution ratio of P, Cr between molten CaO-SiO 2 -FeO-MgO-MnO-Cr 2 O 3 -P 2 O 5 slags and molten steel was obtained by the indirect experimental method and the regular solution model. The results show that the liquidus region and the proportion of liquid phase decrease with the increase of Cr 2 O 3 content in steel slag. The increases of basicity conduces to dechromization and dephosphorization. The L Cr increased continuously with increasing FeO content and the influence of the oxidization of steel slag on the L Cr is greater than L P . Both L P and L Cr decrease distinctly with the increase in temperature. The slag formation path for the smelting process of semi-steel containing chromium is as follows: 17wt-%CaO-16wt-%SiO 2 -67wt-%FeO→25wt-%CaO-20wt-%SiO 2 -55wt-%FeO→57wt-%CaO-17wt-% SiO 2 -6wt-%FeO.

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“…Manganese ore powders with various Mn/Fe mass ratios can refer to these three types of manganese ores. Pyrometallurgical smelting of manganese ores in blast furnaces and electric furnaces constitutes the mainstream production process for Mn alloys in factories [ 9 , 10 , 11 , 12 , 13 ]. In these processes, manganese ore fines or powders are first agglomerated to sinters or pellets, which have superior mechanical and metallurgical properties.…”

Section: Introductionmentioning

confidence: 99%

Physicochemical Aspects of Oxidative Consolidation Behavior of Manganese Ore Powders with Various Mn/Fe Mass Ratios for Pellet Preparation

Zhang

Liu

et al. 2022

Materials

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With the depletion of rich manganese ore resources, plentiful manganese ore powders with various Mn/Fe mass ratios are produced. The physicochemical aspects of oxidative consolidation behavior of manganese ores with various Mn/Fe mass ratios were investigated in this work to determine whether manganese ore powders with high iron content (Fe-Mn ore) can be prepared as high-quality pellets. Physicochemical properties of the pellets were investigated, including cold compression strength (CCS), phase transformation, microstructural evolution, Vickers hardness (HV), porosity, and lattice parameter. CCS testing indicated that the strength of roasted Fe-Mn ore pellets was observably lower than that of pure hematite or manganese ore pellets. Phase and morphology results showed that in Fe-Mn ore pellets, an Mn ferrite phase was generated between hematite and pyrolusite particles. However, newborn Mn ferrites and hematite had an obvious crystal boundary in the crystallographic particles. Moreover, poorly crystallized Mn ferrite particles were evident, along with Mn and Fe element concentration gradients, due to the inadequate diffusion of metal ions. This resulted in poor mechanical properties of the Fe-Mn ore pellets. A temperature over 1275 ∘C and a roasting time of 15 min is required for the oxidative consolidation of Fe-Mn ores. In such optimized cases, Mn, Fe, O, and Al elements were uniformly distributed in the well-crystallized Mn ferrite grains, which provided favorable mineralogy for the consolidation of Fe-Mn ore powders.

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Equilibrium kinetics of manganese-ore carbon-reduction between molten steel and slag

Cited by 9 publications

References 14 publications

Study on Efficient Use of High‐Manganese Pig Iron

Study on Efficient Use of High‐Manganese Pig Iron

Slag formation path in converter smelting process of semi-steel containing chromium

Physicochemical Aspects of Oxidative Consolidation Behavior of Manganese Ore Powders with Various Mn/Fe Mass Ratios for Pellet Preparation

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