Determining the kinetic rate constants of Fe3O4-to-Fe and FeO-to-Fe reduction by H2
Determining the kinetic rate constants of Fe3O4-to-Fe and FeO-to-Fe reduction by H2
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DOI：
10.1016/j.cej.2022.134771
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发表时间：
2022-01-22
影响因子：
15.1
通讯作者：
Huang, Kevin
中科院分区：
文献类型：
--
作者：
Tang, Qiming;Huang, Kevin
使用煤炭的钢铁生产约占全球碳排放量的 8%。 “绿色钢铁”是最近提出的一个新的宏伟概念，利用可再生的“绿色氢”从铁矿石中炼钢，以实现零碳排放。使用 H-2 作为还原剂将铁矿石还原成铁的动力学和限速步骤对于这项新技术的成功至关重要。虽然 H-2 将 Fe2O3 还原成 Fe 需要多个步骤，但过去关于该主题的研究主要涉及整体平均动力学，而对元素和限速步骤提供的信息很少。在这里，我们报告了一项专门设计的动力学研究，旨在获得 Fe3O4 一步还原为 Fe 和 FeO 还原为 Fe 的动力学速率常数。在热力学的指导下，我们首先展示了如何在精确控制 H2O 和 H-2 分压比的情况下原位产生所需的起始氧化物相，即 Fe3O4 和 FeO。然后，我们显示由质谱仪收集的随时间变化的原始 H2O 含量数据以及经过处理的还原数据以提取动力学速率常数。我们发现两个一步还原反应的动力学很好地遵循 Johnson-Mehl-Avrami (JMA) 相变模型。还讨论了一步还原机制和活化能。
Steel production using coal accounts for ~ 8% of global carbon emissions. "Green Steel " is a new grand concept proposed recently to make steel from iron ores using renewable derived "Green Hydrogen " to achieve zero carbon emission. The kinetics and rate-limiting steps of iron ore reduction into iron with H-2 as a reducing agent is critically important to the success of this new technology. While reduction of Fe2O3 into Fe by H-2 follows multiple steps, the past research on this topic mainly deals with the overall averaged kinetics, giving little information on the elemental and rate-limiting steps. Here we report a kinetic study specifically design to attain kinetic rate constants of one-step reduction of Fe3O4-to-Fe and FeO-to-Fe. Guided by thermodynamics, we show first how to create in situ the desirable starting oxide phases, i.e., Fe3O4 and FeO, with precisely controlled the ratio of partial pressures of H2O and H-2. We then show time-dependent raw H2O content data collected by a mass spectrometer and the processed reduction data to extract kinetic rate constants. We found that the kinetics of the two one-step reduction reactions follows nicely the Johnson-Mehl-Avrami (JMA) phase transformation model. The one-step reduction mechanisms and activation energy are also discussed.