This study investigated the interdiffusion of calcium ferrite/calcium titanate system in the time range of 0–120 min by the diffusion couple method in a CO/N 2 reducing atmosphere at 700°C. The results show that after the diffusion reaction occurred, no longitudinal agglomerations were present on the substrate surface on the calcium titanate side. When the diffusion time was increased to 105 min, a net vacancy flow from calcium titanate to calcium ferrite might have occurred, causing the surface of the calcium ferrite substrate to collapse. The thickness of the diffusion layer of the calcium ferrite/calcium titanate system was about 17–48 µm, which conforms to the parabolic law of diffusion. The diffusion coefficient and the Ti 4+ concentration in the calcium ferrite/calcium titanate system are related. This shows an increase in the diffusion coefficient with the increase of Ti 4+ concentration, and the diffusion coefficient value was in the range of 10 −12 –10 −11 cm 2 ·s −1 .
An economic and effective strategy synchronously utilizing blast furnace bag dust (BF-BD) and converter-removing dust (C-RD) by carbothermic reduction roasting is reported to achieve separation and recovery of iron and zinc. In this paper, the effect of operating parameters on the recovery rate and remove rate of Fe and Zn from BD and GD was initially studied by synergetic carbothermic roasting reduction. The optimized parameters include a reduction temperature pf 1200 °C, a reduction time of 90 min, a FC/O of 2.0, and a proportion of C-RD/BF-BD of 7:3, and the removal efficiency of Zn and metallization degree of Fe reached 98.35% and 90.58%, respectively. The phase transformation and stepwise reduction behavior of wüstite (ZnO) x (FeO) 1− x , spinel Zn x Fe 1− x Al 2 O 4 , olivine Zn x Fe 2− x SiO 4 , and gehlenite Zn z Fe 2− x SiAl 2 O 7 are systematically investigated by SEM–EDS, XRD, TG/DTG, and thermodynamic analyses. It was found that the formation of wüstite (ZnO) x (FeO) 1− x as an intermediates plays an crucial role in the formation of metallic Zn–Fe–C alloy. Phase transformation and reduction mechanisms of C-RD and BF-BD and the interfacial reaction formation mechanism of wüstite (ZnO) x (FeO) 1− x were discussed and clarified in synergistic carbothermic reduction process. Graphical Abstract
危险品化学品经营许可证（带存储）