The Oxidation and Decomposition Behavior of Carbonate Iron Ore

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• 作者：Yating Tang ; Mansheng Chu ; Jue Tang ; Lin You and Zhenggen Liu
• 刊名：steel research international
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：88
• 期：2
• 全文大小：1312K
• ISSN：1869-344X

文摘

With the aim of high-efficiency utilization of carbonate iron ore, a new beneficiation process of preoxidation-reduction-magnetic separation is proposed. This work focuses on the oxidation and decomposition behavior of carbonate iron ore during the preoxidation. Based on the single factor experiment and non-isothermal analysis results, it shows that with the increasing of oxidation temperature and time, the oxidation degrees of carbonate iron ore increase rapidly. After oxidizing at 773 K for 30 min, the oxidation degrees OX⁰, D, and y₀ reach 97.36%, 99.12%, and 1.475, respectively. Besides, a porous structure forms with a large amount of cracks after oxidation which is beneficial to the gas diffusion. Then both the oxidation and the decomposition of carbonate iron ore are enhanced consequently. And the main phase and structure transformation of carbonate iron ore during the preoxidation is proceeded as follow as FeCO₃ (rhombohedral crystal) → Fe₃O₄ (cubic crystal) → γ-Fe₂O₃ (cubic crystal) → α-Fe₂O₃ (rhombohedral crystal). Moreover, the nearest mechanism for carbonate iron ore decomposition within 650–950 K is F1 model, which is random nucleation and subsequent growth. And the values of activation energy and pre-exponential factor are 220.64 kJ mol⁻¹ and 1.510 × 10¹⁴ min⁻¹, respectively.