中文摘要：

以高温直接还原工艺为基础，采用大样热重设备在氮气气氛保护下将石墨和稀土复合铁矿混匀压块，然后在1273～1523K条件下研究其直接还原过程。通过改变还原温度、还原时间和碳氧比研究了各工艺参数对稀土铁矿的还原度、金属化率和稀土相的转变过程。实验结果表明当温度高于1323K时，还原进行到30min时试样金属化率即可达到平台期，基于转底炉工艺为参考得出较优还原工艺参数是碳氧比1．0，还原温度1523K，还原时间20min，在此条件下球团金属化率可达85．06％。考察在1273～1523K温度范围内还原动力学，对还原实验结果进行不同控速方程拟合，得出稀土复合铁矿内配碳直接还原反应受三维扩散控制，获得表观活化能为（228．80±12．58）kJ·mol^-1.通过X射线衍射（XRD）对还原过程中稀土复合铁矿矿物矿相进行检测，发现稀土复合铁矿中稀土相的转变路径是：CeC03F→CeOF→Ce4667（SiO4）30和Ca3Ce2[（Six，P1-x）O4]3·F3（1-x）（0〈x〈1）。

英文摘要：

Based on the technology of rotary hearth furnace （RHF） , the rare earth composite iron ore concentrate （RECIOC） was reduced by graphite isothermally under nitrogen gas in thermogravimetry system at 1273 to 1523 K. The influences of reductive conditions on the reduction degree, metallization degree and transformation of rare earth phase including reduction temperature, reduction time and C/O molar ratio were studied. Results showed that metallization degree would get to platform when the temperature was above 1323 K and at 30 rain. The optimum process conditions were that m（ C）： m（O） was 1.0, reduction temperature was 1523 K, reduction time was 20 rain based on RHF technology, which led to 85.06% metallization ratio. According to different matchings of controlling equation, rare earth composite iron ore concentrate reaction process was controlled by Ginstring-Brounshtein, and apparent activation energy was （228.80 ± 12.58 ） kJ·mol^-1. The transformation path was suggested by X-ray diffraction （XRD） as following in the experiment condition ： CeCO3 F→CeOF→Ce4.667 （ SiO4 ） 30 and Ca3 Ce2 [ （ Six, Pl -x ） 04 ] 3·F3（1 -x）（ 0 〈 x 〈 1 ）.