Based on the new process named “Combination Method” for metallurgy and separation of Baotou mixed rare earth concentrate (BMREC), the aim of this paper is to clearly elucidate the phase change behavior of BMREC without additives during oxidative roasting at 450–800 °C. The results indicate that the bastnaesite in BMREC is decomposed at 450–550 °C, the weight loss is about 10.3 wt%, and the activation energy (E) is 144 kJ/mol. The bastnaesite in BMREC is decomposed into rare earth fluoride, rare earth oxides (La₂O₃, Ce₇O₁₂, Pr₆O₁₁ and Nd₂O₃), and CO₂, particularly, with the increase of roasting temperature, bastnaesite in BMREC is more completely decomposed into LaF₃, which causes a decrease in leaching rate of La during the HCl leaching process. Additionally, the maximum cerium oxidation efficiency reaches about 60 wt% when the roasting temperature is equal to or above 500 °C, and the oxidation reaction rate of cerium increases with the increasing roasting temperature.

本文基于包头混合稀土精矿（BMREC）冶金分离新工艺“组合法”，旨在阐明无添加剂BMREC在450~800℃氧化焙烧过程中的相变行为。 . 结果表明，BMREC中氟碳铈矿在450~550 ℃分解，失重约为10.3 wt%，活化能（E）为144 kJ/mol。BMREC 中的氟碳铈矿分解成稀土氟化物、稀土氧化物（La ₂ O ₃、Ce ₇ O ₁₂、Pr ₆ O ₁₁和 Nd ₂ O ₃）和 CO ₂特别是随着焙烧温度的升高，BMREC中氟碳铈矿更完全地分解为LaF ₃，导致在HCl浸出过程中La的浸出率降低。另外，当焙烧温度等于或高于500 ℃时，铈的最大氧化效率达到约60 wt%，并且铈的氧化反应速率随着焙烧温度的升高而增加。