Preparation of briquettes by adding CaF₂ reagent into the Australian iron ore powder. The structure and morphology of iron ore briquettes during various reduction stages (i.e., Fe₂O₃→Fe₃O₄, Fe₃O₄→FeO, and FeO→Fe) were observed via an ore microscope and scanning electron microscopy. The results showed that CaF₂ reacted with SiO₂ to form CaO and SiF₄ gas during the roasting process. The reduction swelling index decreased from 12.36 to 8.83% when the CaF₂ content in the briquettes increased due to CaF₂-mediated refinement of the hematite grains during the first stage of the reduction process. Lattice distortion resulting from the presence of Ca²⁺ in the FeO lattice during the second stage of the reduction process, coupled with an increase in the porosity of the iron ore briquettes and the formation of a low-melting-point slag phase, promoted the anisotropic growth of FeO lamellar crystals, which resulted in an increase in the reduction swelling index from 4.27 to 7.36%. During the third stage of the reduction process, the growth of iron whiskers was promoted by wüstite (FeO) lattice distortion caused by a solid solution of Ca²⁺ in the FeO lattice; the reduction swelling index increased from 15.61 to 24.72%, resulting in the catastrophic swelling of the iron ore briquettes.

在澳大利亚铁矿石粉中加入CaF ₂试剂制备型煤。通过矿石显微镜和扫描电子显微镜观察不同还原阶段（即Fe ₂ O ₃ →Fe ₃ O ₄、Fe ₃ O ₄ →FeO 和FeO→Fe）的铁矿石压块的结构和形貌。结果表明的CaF ₂与反应的SiO ₂以形成CaO和的SiF _4分时的烘烤过程中的气体。由于CaF ₂增加，煤球中CaF ₂含量增加，还原溶胀指数从12.36%下降到8.83%- 在还原过程的第一阶段介导的赤铁矿晶粒细化。在还原过程的第二阶段，由于 FeO 晶格中存在 Ca ²⁺导致的晶格畸变，加上铁矿石压块孔隙率的增加和低熔点渣相的形成，促进了FeO 层状晶体的各向异性生长，导致还原溶胀指数从 4.27% 增加到 7.36%。在还原过程的第三阶段，FeO 晶格中 Ca ²⁺固溶引起的方铁矿 (FeO) 晶格畸变促进了铁晶须的生长；还原溶胀指数从15.61%增加到24.72%，导致铁矿石型煤发生灾难性溶胀。