Nickel is a silvery white metal that takes on a high polish. It belongs to the iron group, and is hard, malleable, and ductile. It occurs combined with sulfur in millerite, with arsenic in the mineral niccolite, and with arsenic and sulfur in nickel glance. Nickel is one of the five ferromagnetic elements.
Nickel can be recovered using extractive metallurgy. Oxy-hydroxide ores are treated using hydrometallurgy, and from sulfide mineral concentrates using pyrometallurgical or hydrometallurgical techniques. Sulfide mineral concentrates are produced by applying the froth flotation process.
Nickel is extracted from its ores by conventional roasting and reduction processes which yield a metal of >95% purity. Final purification to >99.99% purity is performed by reacting nickel and carbon monoxide to form nickel carbonyl. This gas is passed into a large chamber at a higher temperature in which tens of thousands of nickel spheres are maintained in constant motion. The nickel carbonyl decomposes depositing pure nickel onto the nickel spheres. The resultant carbon monoxide is re-circulated through the process. The highly pure nickel produced by this process is known as carbonyl nickel.
The largest producer of nickel is Russia which extracts 267,000 tonnes of nickel per year. Australia and Canada are the second and third largest producers.
Largest use of nickel is as component of steels and other alloys. Nickel is a construction material for chemical apparatus, nuclear reactors, accumulators.