The non-isothermal kinetic method was used in this manuscript to obtain the reaction models by fitting the reduction ratio of low-grade phosphate ore and the volatilization ratio of phosphorus. And the reaction mechanism of vacuum carbothermal reduction of low-grade phosphate was investigated by combining XRD, SEM, EDS, chemical analysis, and FactSage7.2. Ca₅(PO₄)₃F first reacted with a small amount of SiO₂ in the ore sample at 1080 °C to form Ca₃(PO₄)₂, CaSiO_3, and SiF₄ (escaped in the form of gas). Then, Ca₃(PO₄)₂ was reduced by C. When the temperature reached approximately 1300 °C, a large number of Ca₅(PO₄)₃F in ore sample began to react with C to form CaO, P₂(g), CO(g), and CaF₂. Through the mutual verification of Coats-Redfern and Šatava-Šesták methods, it is concluded that the unitary reduction process was under the control of the shrinking core model, and the activation energy of unitary reduction was 74.54±10.39 kJ/mol. The volatilization of P was under the control of the 3-D diffusion (anti-Jander), and the activation energy was 416.43±1.81 kJ/mol.

该手稿采用非等温动力学方法，通过拟合低品位磷矿的还原率和磷的挥发率来获得反应模型。结合XRD，SEM，EDS，化学分析和FactSage7.2，研究了低级磷酸盐真空碳热还原反应的机理。Ca ₅（PO ₄）₃ F首先在1080°C下与矿石样品中的少量SiO ₂反应形成Ca ₃（PO ₄）₂，CaSiO ₃和SiF ₄（以气体形式逸出）。然后，Ca ₃（PO ₄）₂当温度达到约1300°C时，矿石样品中大量的Ca ₅（PO ₄）₃ F开始与C反应形成CaO，P ₂（g），CO（g）和CaF ₂。通过对Coats-Redfern方法和Šatava-Šesták方法的相互验证，得出的结论是，一元还原过程是在收缩核模型的控制下进行的，一元还原的活化能为74.54±10.39 kJ / mol。P的挥发受3-D扩散控制（抗Jander），活化能为416.43±1.81 kJ / mol。