Pre-concentration of vanadium from stone coal by gravity separation

• A new process for vanadium pre-concentration from stone coal was researched.
• The mineralogy on the stone coal was investigated.
• The process can improve V2O5 grade and decrease acid consuming mineral content.

In China, more than 87% of vanadium is discovered from stone coal. However, because the vanadium grade in stone coal is generally low, current vanadium extraction technology faces challenges in terms of large ore tonnage and high energy consumption, acid consumption and cost.A new process for pre-concentration of vanadium from stone coal by gravity separation was investigated based on mineralogical study. It was confirmed that the vanadium occurred in muscovite and illite, and the acid consuming minerals were pyrite and calcite. The process comprised three key steps: decarburization, selective grinding and gravity separation. In the decarburization stage, the thermal energy of carbon in the stone coal can be used and the V2O5 grade increased to some extent. The differences of V2O5 grade among different size fractions increased through the selective grinding stage. In the gravity separation stage, 28.9% of the feed ore were rejected as final tailings, while the V2O5 loss was 9.7%. The pre-concentration of vanadium from stone coal can improve the V2O5 grade and decrease the content of high acid consuming minerals. The benefits of the pre-concentration process in terms of cost savings and solving processing problems were discussed.