In the form of flakes in brown colour, mainly used in the manufacture of ferrovanadium alloy and other alloys in metallurgy industry; in the form of powder, mainly used in the decarbonization and d esulphurization in the production of synthetic ammonium; as stains and catalysts in dyeing, glass and ceramics industry; as catalysts in the production of sulphuric acid and in petrochemical industry; used in the manufacture of vanadi um compounds for the production of phosphorus fertilizers and nylon.