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以钒钛铁精矿和煤粉为原料,在空气气氛下通过碳热还原法制备Fe-Ti(C,N)复合粉末。通过还原产物X射线衍射分析,对空气气氛下还原温度和配碳量对钒钛铁精矿碳热还原的反应过程以及物相演变进行了研究。结果表明,随着温度的升高,反应过程中的物相演变过程为:Fe_3O_4→Fe,Fe TiO_3→Fe Ti_2O_5→Ti_4O_7→Ti_2O_3→Ti(C,N),配碳量是使反应体系处于气相平衡的关键因素。在配碳量<25%时,体系内CO、CO_2和N2的分压不能达到平衡或维持反应平衡的时间很短,钒钛铁精矿不能被还原或只能部分被还原为Ti(C,N)。在还原温度1 500℃,还原时间30 min,配碳量30%的条件下,还原产物中Ti C_(1-x)N_x的颗粒尺寸约为3μm,Ti C_(1-x)N_x的C/N值为0.491 5,x=0.67。
Fe-Ti (C, N) composite powder was prepared by carbothermal reduction method using vanadium-titanium-iron ore concentrate and pulverized coal as raw materials. Through the X-ray diffraction analysis of the reduction products, the reaction process and phase evolution of vanadium-titanium iron ore concentrate by carbothermal reduction with reduction temperature and carbon content in air were studied. The results show that with the increase of temperature, the phase evolution of the reaction process is: Fe 3 O 4 → Fe, Fe TiO 3 → Fe Ti 2 O 5 → Ti 4 O 7 → Ti 2 O 3 → Ti (C, N) The key to balance. When the carbon content is less than 25%, the partial pressure of CO, CO_2 and N2 in the system can not reach equilibrium or keep the reaction equilibrium for a short time. The vanadium-titanium-iron concentrate can not be reduced or can only be partially reduced to Ti (C, N). The particle size of Ti C 1-x N x in the reduction product was about 3 μm at the reduction temperature of 1 500 ℃, the reduction time of 30 min and the carbon content of 30%. The C / N value 0.491 5, x = 0.67.