Experimental and quantum chemical investigations on the generation mechanism of Al-V intermediate alloy by aluminothermic reduction of NaVO3

Abstract

In the present study, the reaction process and reaction mechanism of the aluminothermic reduction of NaVO3 to prepare aluminum-vanadium intermediate alloy were investigated by experimental analysis and quantum chemical calculations. The results of thermal analysis and isothermal experiments indicated that the aluminothermic reduction of NaVO3 was a multi-step process and temperature played a critical role in this process. The aluminum-vanadium intermediate alloy was generated when the temperature exceeded 963 ºC, and it could be further separated from the reduction product after the addition of slag-forming agents (CaO and CaF2) at 1600 ºC. Furthermore, an atomic-level insight into the reaction between aluminum and NaVO3 was explored based on the electrostatic potential (ESP) analysis of the reactivity of NaVO3. The results showed that the aluminum atom first interacted with NaVO3 to form an intermediate complex through electrostatic interaction, and then NaVO3 was reduced to NaVO2 under the continuous action of aluminum. Further, the newly formed NaVO2 was consequently converted to aluminum-vanadium intermediate alloy under the continuous action of aluminum atoms. These theoretical results were essentially consistent with the experimental data, which provided a fundamental understanding about the reaction mechanism of NaVO3 with Al. Moreover, the aluminothermic reduction of NaVO3 also provided a feasible and environmentally friendly metallurgical approach for preparing aluminum-vanadium intermediate alloy.