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Structures and Reduction Kinetics of Pelletized Rich Iron Ores for Iron Production: a Case Study for Na Rua Iron Ore in Vietnam
Mining, Metallurgy & Exploration ( IF 1.9 ) Pub Date : 2022-07-07 , DOI: 10.1007/s42461-022-00646-5
Kien Trung Nguyen, Hoan Thanh Nguyen, Bac Quang Nguyen, Chuc Ngoc Pham, Dung Trung Doan, Chi Thi Ha Nguyen, Lim Thi Duong, Hoa Anh Bui, Que Anh Nguyen, Thuat Ngoc Pham, Du Duy Bui, Nhiem Ngoc Dao

The microstructures and kinetics of a rich iron ore (TFe = 65.84%) of Na Rua mine, Vietnam, used for the iron production were investigated in this study. Thermal behaviors of iron ores were well-examined by heating microscopy, thermogravimetric analysis, and differential thermal analysis. After being pelletized and then oxidatively fired at 500–1200 °C for 2 h, the pellets fired at 1200 °C (P1200) displayed a hard and dense structure with a decent compressive strength of 317.9 kg/pellet whereas those fired at 500 °C (P500) had a soft and spongy structure. The reduction of iron pellets conducted in a flow of a 60–100% CO2/Ar gas mixture at 900–1100 °C showed significantly higher efficiency than the reduction using coal. The spongy pellets showed superior performance for the reduction in the CO/Ar gas mixture compared to the dense ones, compatible with the production of sponge iron. When mixed with an amount of coal, P1200 designed for iron production in the blast furnace demonstrated an impressive reduction activity compared to P500 and previous studies. The kinetics of pellet reduction was determined by the diffusion of substances through the solid product layers having the mathematical model of \(1- \frac{2}{3}f- {\left(1-f\right)}^{2/3}=kt\). The microstructures of pellets during the oxidative firing and reduction were also examined by X-ray diffractometry; scanning electronic microscopy; energy-dispersive X-ray spectroscopy; and Brunauer, Emmet, and Teller method.



中文翻译:

铁生产用球状富铁矿石的结构和还原动力学:以越南 Na Rua 铁矿石为例

 本研究研究了用于生产铁的越南 Na Rua 矿的富铁矿石 (T Fe = 65.84%) 的微观结构和动力学。通过加热显微镜、热重分析和差热分析对铁矿石的热行为进行了深入研究。造粒后在 500-1200 °C 下氧化烧制 2 小时后,在 1200 °C 下烧制的颗粒 (P1200) 显示出坚硬致密的结构,抗压强度为 317.9 kg/颗粒,而在 500 °C 下烧制的颗粒(P500) 具有柔软的海绵状结构。在 60–100% CO 2的流动中进行铁球团的还原/Ar 气体混合物在 900–1100 °C 的效率显着高于使用煤的还原。与致密颗粒相比,海绵颗粒在减少 CO/Ar 气体混合物方面表现出优异的性能,与海绵铁的生产相容。当与一定量的煤混合时,设计用于高炉炼铁的 P1200 与 P500 和之前的研究相比表现出令人印象深刻的还原活性。颗粒减少的动力学由物质通过固体产品层的扩散确定,数学模型为\(1- \frac{2}{3}f- {\left(1-f\right)}^{2 /3}=kt\). 还通过X射线衍射法检查了氧化烧制和还原过程中球团的微观结构;扫描电子显微镜;能量色散 X 射线光谱仪;以及 Brunauer、Emmet 和 Teller 方法。

更新日期:2022-07-08
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