Vanadium Recovery from Combustion Ash of Orinoco Tar in Venezuela

摘要

Vanadium is added to the special steel like tool, ship and pipe. Vanadium is produced as a by-product of other metals or recovered from petroleum refining catalyst. Recently, attention has been given to Orinoco tar combustion ash as vanadium resource, because the ash contains more than 20 mass% V2O5. In the first step, vanadium recovery was tried from the combustion ash of Orinoco tar in the present work. The ash mixed CaO was reduced with carbon at 1773K. The mixed sample melted completely and separated into slag and metal containing vanadium carbide at the temperature. Vanadium was not observed in slag phase, and it meant that all of vanadium in ash was recovered as VC in the metal phase. The metal was Fe-Ni alloy. In the second step, Fe-Ni-V-C quo-ternary isothermal section phase diagram was experimentally assembled at 1773K. As the result, the mechanism of vanadium recovery from Orinoco tar combustion ash by reduction with carbon was discussed based on the Fe-Ni-V-C phase diagram system and generating gas species analysis in the heating process.