Regular Article

Preparation of high quality FeV65N by carbonitrothermic reduction of V₂O₅ and Fe₂O₃

State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, PR China

^* e-mails: ghzhang0914@ustb.edu.cn; ghzhang_ustb@163.com

Received: 2 April 2018
Accepted: 4 October 2018

Abstract

In this work, high quality FeV65N alloy (vanadium and nitrogen contents were 65 and 13 wt.%, respectively) is prepared by carbonitrothermic reduction reaction at 1823 K among V₂O₅, Fe₂O₃ and graphite. Compared with the traditional methods, it avoids the preparation of ferrovanadium, thus decreases the cost and energy consumption. Moreover, the introduction of Al or Si element is avoided. The effects of the C/O molar ratio and reaction temperature on the nitrogen, carbon and oxygen concentrations of the final product are studied. The experimental results show that a higher temperature is beneficial for increasing the nitrogen content and density of FeV65N alloy. The C/O molar ratio is critical to obtain a high nitrogen concentration. A higher or lower C/O molar ratio will result in the decrease of the nitrogen concentration. At a C/O molar ratio of 0.8, the carbon and nitrogen contents of FeV65N alloy prepared at 1823 K are 0.066 and 16.19 wt.%, respectively. The compositions completely fulfill the requirements of Chinese national standard of FeV65N alloy. Moreover, the density of FeV65N alloy can be up to 3.99 g/cm³. Furthermore, the effect of Fe addition on the carbon, oxygen and nitrogen contents is studied. It is found that the addition of Fe can increase the nitrogen content and further remove oxygen and carbon, since it provides a liquid tunnel for carbon diffusion, which enhances the reaction kinetics greatly.