How does aluminum reduction produce a vanadium regulus?

In the production of pure vanadium metal, the aluminothermic process is used to reduce vanadium pentoxide ($V_2{O}_5$) by mixing it with aluminum powder. This mixture is then either heated in an electric furnace or ignited within a refractory-lined vessel, typically using barium peroxide as a thermal booster to facilitate the reaction. The resulting vanadium regulus can subsequently be further purified through electron-beam melting.1