Extraction of vanadium from low-vanadium grade magnetite concentrate pellets with sodium salt

This study reported the extraction of vanadium from low-vanadium grade magnetite concentrate pellets using sodium salt. 71.1% of vanadium can be extracted under the following optimal conditions: pelletizing with 5 wt% Na2CO3, preheating at 1050 °C for 10 min, roasting at 1250 °C for 10 min, and water leaching at 120 °C for 120 min with a liquid:solid ratio of 5:1 (mL/g) in the bench-scale experiment. XPS and SEM-EDS results showed that part of trivalent vanadium was not oxidized completely during the sodium salt roasting and still occurred in the iron mineral phase; consequently, this part of vanadium was retained in the leached iron ore. The sodium salt roasting parameters are consistent with those of the iron ore oxidized pellets produced by grate-kiln or straight-grate methods; thus, the production efficiency of sodium salt roasting for vanadium extraction can be improved significantly. Pilot-scale experiment was further performed to verify the feasibility of the recommended method in a traveling grate, a better vanadium extraction ratio of 79.1% was achieved.