碳热还原氮化攀钢高钛高炉渣制取Ti(C,N)的研究

Preparation of Ti(C,N) from titanium-bearing blast furnace slag in Panzhihua Iron & Steel Co by carbothermal reduction-nitridation

以攀钢高炉渣(粒度≤0.074mm,w(TiO2)=21.19%)和炭黑(w(C)=98%)为原料,在密封管式炉中通入流量0.5L·min-1的工业N2(纯度>95%),分别在1300℃、1350℃、1400℃、1450℃、1500℃保温2h以及在1450℃下分别保温0、2h、4h、6h、8h的条件下,采用碳热还原氮化法制备了Ti(C,N)。用X射线衍射仪、电子探针、图像分析仪等研究了碳氮化处理温度及保温时间对Ti(C,N)的形成及其晶粒大小的影响。结果表明碳氮化处理温度对高炉渣中Ti(C,N)的形成过程产生显著影响,温度从1300℃升至1500℃时,产物中Ti(C,N)的相对含量增大,其晶粒也逐渐长大,但超过1450℃后,影响又不太显著;在1450℃下延长保温时间能促进Ti(C,N)的生成与晶粒长大,但保温时间超过2h后,此促进作用又不太明显。

Ti（C,N） were prepared using titanium-bearing blast furnace slag （≤0.074 mm,w（TiO2）=21.19%） in Panzhihua Iron ＆ Steel Coand carbon black （w（C）=98%） as starting materials by carbothermal reduction-nitridation method in a vertical tube furnace.Reaction was performed at 1 300 ℃,1 350 ℃,1 400 ℃,1 450 ℃ and 1 500 ℃,respectively for 2 h and at below 1 450 ℃ for 0,2 h,4 h,6 h and 8 h in nitrogen atmosphere at flow rate of 0.5 L·min^-1（〉95% purity）.The effect of nitriding temperature and holding time on formation and. grain size of Ti（ C, N） were studied by X-ray diffractometry, Electron probe microanalysis （EPMA） and micro-image analysis. The results show that nitriding temperature significantly affects Ti（C,N） formation. With the increase of nitriding temperature from 1 300 ℃ to 1.500 ℃,the relative content and grain size of Ti（C,N） in products increase. But no significant change occurs after rising over 1 450 ℃. It is helpful to facilitate the formation and growth of Ti（C,N） by extending the holding time at 1 450 ℃ but no more than 2 h.