氟磷灰石还原的影响因素和等温动力学

来源期刊:中国有色金属学报2020年第2期

论文作者:栗艳锋 孙永升 韩跃新 王定政

文章页码:431 - 438

关键词:氟磷灰石;Ca10(PO4)6F2-SiO2-Fe2O3-C体系;影响因素;动力学方程

Key words:fluoropatite; Ca10(PO4)6F2-SiO2-Fe2O3-C system; influencing factors; kinetic equation

摘    要:为深入了解高磷铁矿煤基还原过程中氟磷灰石还原行为的影响因素和等温动力学参数,试验采用纯矿物配比的方式研究了二氧化硅含量、氧化铁含量、碳用量、还原时间和还原温度对磷灰石还原度的影响,并在此基础上,探明Ca10(PO4)6F2-SiO2-Fe2O3-C体系下氟磷灰石还原的等温动力学机理函数和动力学方程。结果表明:在一定的条件下,增加二氧化硅、氧化铁、碳用量、还原时间或还原温度均能够促进氟磷灰石的还原反应。在Ca10(PO4)6F2-SiO2-Fe2O3-C体系中,二氧化硅和氧化铁与氟磷灰石的最佳含量比分别为1.8和2.2,最佳C/O摩尔比为2.0。在最佳反应物用量条件下,氟磷灰石深度还原的最佳动力学机理函数为A1/3:1/3(1-α)[-ln(1-α)]-2;最佳动力学方程为:k(T)=3.89033×107exp(-282.748×103/RT),其中,指前因子为3.89033×107 min-1,活化能为282.748 kJ/mol。还原反应的限制环节为固态扩散。

Abstract: To study the influencing factors and isothermal kinetic parameters of fluoropatite reduction in the process of coal-based reduction of high-phosphorus iron ore, the effects of reduction time, reduction temperature, and content of silica, iron oxide or carbon on reduction degree of fluorapatite were studied by mixing pure minerals in the experiment. On this basis, the reduction kinetic mechanism function and isothermal kinetic equation of fluoroapatite in Ca10(PO4)6F2-SiO2-Fe2O3-C system were investigated. The results show that increasing the amounts of silica, iron oxide and carbon, and decreasing time and temperature, can accelerate the reduction reactions of fluoroapatite under experiment conditions. In Ca10(PO4)6F2-SiO2-Fe2O3-C system, the optimum ratios of silica, iron oxide comparing to fluorapatite are 1.8 and 2.2, respectively, and the optimal C/O molar ratio is 2.0. Based on the optimum amount of reactants, the best mechanism function for the reduction of fluoroapatite is the A1/3: 1/3(1-α)[-ln(1-α)]-2; the best kinetic equation is K(T)=3.89033×107exp(-282.748×103/RT), where the pre-exponential factor is 3.89033×107 min-1, and the activation energy is 282.748 kJ/mol. The limiting factor of the reduction reaction is solid-state diffusion.

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