How is ammonium metavanadate converted into vanadium pentoxide?

To convert ammonium metavanadate into vanadium pentoxide ($V_2{O}_5$), the precipitate is first filtered and dried. Once prepared, it undergoes a process called calcination, which converts the compound into high-purity vanadium pentoxide.1

The specific steps for obtaining this precipitate can vary depending on the source material:

• From carnotite: After vanadium is extracted in a solvent circuit and stripped with a soda ash solution, it is precipitated using ammonium sulfate. The resulting ammonium metavanadate is then filtered, dried, and calcined to produce $V_2{O}_5$.1
• From other ores or slags: After the material is roasted and leached, the vanadium is often precipitated as "red cake" (sodium hexavanadate). This can be purified by dissolving it in an aqueous solution of sodium carbonate. After adjusting the acidity to remove impurities, ammonium chloride is added to precipitate the vanadium as ammonium metavanadate. This precipitate is then filtered and calcined to yield $V_2{O}_5$ with a purity greater than 99.8 percent.1