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Qiang Zhang, Yongsheng Sun, Yuexin Han, Yanjun Li, and Peng Gao, Reaction behavior and non-isothermal kinetics of suspension magnetization roasting of limonite and siderite, Int. J. Miner. Metall. Mater., 30(2023), No. 5, pp.824-833. https://dx.doi.org/10.1007/s12613-022-2523-3
Qiang Zhang, Yongsheng Sun, Yuexin Han, Yanjun Li, and Peng Gao, Reaction behavior and non-isothermal kinetics of suspension magnetization roasting of limonite and siderite, Int. J. Miner. Metall. Mater., 30(2023), No. 5, pp.824-833. https://dx.doi.org/10.1007/s12613-022-2523-3
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褐铁矿和菱铁矿悬浮磁化焙烧反应行为及非等温动力学

摘要: 为实现褐铁矿资源的低碳开发利用,本研究提出以菱铁矿作为清洁还原剂用于褐铁矿的磁化焙烧。在菱铁矿用量40wt%、焙烧温度700°C、焙烧时间10 min的最佳悬浮磁化焙烧条件下,磁选可以获得铁精矿铁品位65.92wt%、铁回收率98.54wt%的良好指标。磁性分析表明,悬浮磁化焙烧实现了弱磁性铁矿物向强磁性铁矿物的转化,从而实现了通过弱磁选回收铁矿物。相变分析表明,在悬浮磁化焙烧过程中,褐铁矿首先脱水并转化为赤铁矿,然后菱铁矿分解生成磁铁矿和CO,其中CO将新形成的赤铁矿还原为磁铁矿。微观结构演化分析显示,新生磁铁矿颗粒疏松多孔,颗粒结构明显破坏,有利于后续磨矿。非等温动力学分析结果表明,褐铁矿和菱铁矿之间的主要反应符合二维扩散机制,表明反应过程主要受CO扩散控制。试验结果为使用菱铁矿作为悬浮磁化焙烧的清洁还原剂提供了理论依据。

 

Reaction behavior and non-isothermal kinetics of suspension magnetization roasting of limonite and siderite

Abstract: In order to develop limonite and decrease CO2 emissions, siderite is proposed as a clean reductant for suspension magnetization roasting (SMR) of limonite. An iron concentrate (iron grade: 65.92wt%, iron recovery: 98.54wt%) was obtained by magnetic separation under the optimum SMR conditions: siderite dosage 40wt%, roasting temperature 700°C, roasting time 10 min. According to the magnetic analysis, SMR achieved the conversion of weak magnetic minerals to strong magnetic minerals, thus enabling the recovery of iron via magnetic separation. Based on the phase transformation analysis, during the SMR process, limonite was first dehydrated and converted to hematite, and then siderite decomposed to generate magnetite and CO, where CO reduced the freshly formed hematite to magnetite. The microstructure evolution analysis indicated that the magnetite particles were loose and porous with a destroyed structure, making them easier to be ground. The non-isothermal kinetic results show that the main reaction between limonite and siderite conformed to the two-dimension diffusion mechanism, suggesting that the diffusion of CO controlled the reaction. These results encourage the application of siderite as a reductant in SMR.

 

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