Vanadium is a monocrystal metal. It is grey and it is a transition element. Vanadium has a high melting point of 1890℃ and boiling point of 3380℃. The density of vanadium is 6.110 g/cm3 at room temperature. It is a refractory metal including niobium, tantalum, tungsten and molybdenum. Vanadium possesses qualities of ductility, hard grain, nonmagnetic. It is not easy to oxidize in the air and it can be dissolved in hydrofluoric acid, nitric acid and aqua regia. Furthermore, vanadium is resistant to corrosion and rather stable in alkali, sulfuric acid, hydrochloric acid. Vanadium is widely used in metallurgy, space navigation, chemical engineering and battery industries in the form of ferro-vanadium and vanadium compounds.
The extraction of vanadium in China is mostly from vanadium ore and stone coal with technical process of sodium salt roasting--water immersion--acid deposition--alkaline bath--ammonium salt deposition--metavanadic acid ammonium pyrolysis. The shortage of this process indicates it generates great amount of hydrogen chloride, chlorine poisonous gas during the process of roasting. In addition, there are lots of salts in the sewage water which contaminate environment severely and vanadium conversion rate is low. To solve these issues, many experts did a large deal of researches. They found out a good method of raw ore oxidation roasting--alkaline leaching, calcium salt roasting--ammonium carbonate leaching, raw ore acid leaching or boiling out-furnace carbonic acid leaching, bacterial leaching--sodium salt roasting--water leaching residues and etc.
Vanadium is an important alloyed element mainly used in steel industry. The steel containing vanadium has great intensity, big ductility, good abrasive resistance and so on. It can be broadly applied in machineries, automobiles, shipbuilding, railways, aviation, bridges, electronic techniques, national defense and etc. which accounts for 85% of vanadium consumption. Among of these fields, steel industry occupies the most, so requests from steel field directly affects the vanadium market. Approximately 10% of world' s vanadium is used for producing titanium alloys in aerospace. Vanadium is a stabilizer and reinforcer which can enhance ductility and plasticity of titanium alloys. In addition, Primarily vanadium can be used as catalyst and enhancer in chemical industry. Vanadium is also applied in producing rechargeable hydrogen or vanadium redox storage battery.