Vanadium Pentoxide From Iron Ores

V-containing iron ores are, as mentioned, important vanadium raw materials. The metal can be extracted in two ways. 

After ore dressing a vanadium-rich concentrate is mixed with soda. Roasting (heating with free access of air) gives sodium vanadate, which is leached out with water. 

With sulfuric acid a vanadium hydroxide is precipitated that can be redissolved in soda to a pure soluhon of sodium vanadate. Addition of ammonium chloride precipitates white crystalline ammonium vanadate NH VO. This can be calcined to give orange vanadium pentoxide, suitable for production of pure vanadium and of fer-rovanadium. 

2 Roasting of Steel Manufacturing Slag with Soda 

Pig iron (raw iron) is manufactured in a blast furnace. The vanadium content stays in the raw iron. During subsequent steel manufacture, oxygen is blown over or through the melt to oxidize and remove the carbon. At the same time vanadium is oxidized and the oxide goes to the slag. This slag can be used as raw material for the soda roasting process to extract vanadium. 

---

Most foreiga vanadium is obtained as a coproduct of iron and titanium. South Africa, Norway, and Finland are suppHers. Chile produces slag from an iron operation. AustraUa s first vanadium operation started produciag fused pentoxide flake from a vanadium mine ia 1980. Russia and the People s Repubhc of china produce slag and pentoxide from iron—titanium ores. 

Vanadium is widely, but sparsely, distributed in the earth s crust (Byerrum et al. 1974 Windholz 1983). It may be found at levels as great as 0.07% in the lithosphere and exists in the form of over 50 different mineral ores (Grayson 1983). The principal ores are carnotite, patronite, roscoelite, and vanadinite (Grayson 1983 Byerrum et al. 1974 Weast 1969 Windholz 1983). Vanadium is also found in phosphate rock, some iron ores, and crude petroleum deposits. Flue-gas deposits from oil-fired furnaces have been found to contain up to 50% vanadium pentoxide (Brooks 1986 Grayson 1983 Symanski 1983 Weast 1969). 

---