The abundant refractory titanomagnetite (TTM) provides a cheap alternative source of iron, but this ore contains impurities and is difficult to process to make suitable concentrates for the blast furnace. In this study, reduction roasting of a primary TTM concentrate followed by magnetic separation was investigated to understand the effects of reduction time, coal dosage, and CaF₂ addition on the reduction behavior of TTM and growth mechanism of iron particles. The phase composition of reduced samples was characterized by X-ray diffraction. The size distribution of iron particles was quantitatively examined using image analysis. Results showed that CaF₂ can help improve the reduction degree and particle size of metallic iron. The metallization degree increased from 85.5% to 89.5% when the CaF₂ dosage increased from 0% to 4%, while a minor increase was observed when the CaF₂ dosage exceeded 4%. Accordingly, the TTM samples were treated by reduction roasting with 4% CaF₂ and 25% coal at 1200°C for 60 min followed by magnetic separation. A magnetic concentrate with an iron content of 91.1% and a recovery of 92.9% was achieved. In addition, the relationship between the size distributions of iron particles and grinding fineness was also studied. The size distribution using data from the diameter of iron particles was found to be close to the actual grinding fineness.

丰富的难熔钛磁铁矿（TTM）提供了廉价的铁替代原料，但该矿石含有杂质，难以加工成适合高炉的精矿。在这项研究中，主要的TTM精矿的还原焙烧，然后进行磁选进行了研究，以了解还原时间，煤用量和CaF _2的添加对TTM还原行为和铁颗粒生长机理的影响。还原样品的相组成通过X射线衍射表征。使用图像分析定量检查铁颗粒的尺寸分布。结果表明，CaF ₂可以帮助提高金属铁的还原度和粒径。当CaF ₂剂量从0％增加到4％时，金属化程度从85.5％增加到89.5％，而当CaF ₂剂量超过4％时，观察到轻微的增加。因此，通过在1200°C下用4％CaF ₂和25％煤还原焙烧60分钟来处理TTM样品，然后进行磁分离。获得了铁含量为91.1％且回收率为92.9％的磁性精矿。另外，还研究了铁颗粒尺寸分布与磨削细度之间的关系。发现使用来自铁颗粒直径的数据进行的尺寸分布接近于实际的研磨细度。