Kinetics of vanadium reduction from slags by solid carbon

The laboratory investigation results of the vanadium reduction are presented. Experiments were performed with CaO-SiO2-Al2O3-MgO-V2O3 slags in an air atmosphere. The solid carbon was used as a reducing agent. The reduction kinetics was studied by sampling. It has been shown that reduction proceeds to VC carbide. The process rate is inversely proportional to the slag viscosity. The formation of a carbide film on the carbon surface leads to a sudden, by an order of magnitude, reduction in the rate. The process of vanadium reduction from oxide melts by solid carbon is electrochemical in nature and is limited by the stage of carbon anodic oxidation. The influence of slag viscosity on the process kinetics is explained by the fact that it is controlled by the growth rate and removal of gas bubbles. The appearance of the carbide film, apparently, transfers the reduction process into the intra diffusion mode, when the transfer of carbon and vanadium through the carbide film is limiting. © Published under licence by IOP Publishing Ltd