Nickel is present in over 3,000 different alloys that are used in over 300,000 products for consumer, industrial, military, transport/aerospace, marine and architectural applications.
Nickel’s biggest use, about 65%, is in alloying – particularly with chromium and other metals to produce stainless and heat-resisting steels. Its primary function is to stabilize the austenitic (face-centered cubic crystal) structure of the steel. Normal carbon steel will, on cooling, transform from an austenite structure to a mixture of ferrite and cementite. When added to stainless steel nickel stops this transformation keeping the material fully austenite on cooling. Austenitic stainless steels have high ductility, low yield stress and high tensile strength when compared to carbon steel – aluminum and copper are examples of other metals with the austenitic structure.
Another 20% is used in other steels, non-ferrous alloys (mixed with metals other than steel) and super alloys (metal mixtures designed to withstand extremely high temperatures and/or pressures or have high electrical conductivity) often for highly specialized industrial, aerospace and military applications.
About 9% is used in plating to slow down corrosion and 6% for other uses, including coins, electronics, in *batteries for portable equipment and hybrid cars, as a catalyst for certain chemical reactions and as a colorant – nickel is added to glass to give it a green color. In many of these applications there is no substitute for nickel without reducing performance or increasing cost.
*Rechargeable nickel-hydride batteries are used for cellular phones, video cameras, and other electronic devices. Nickel-cadmium batteries are used to power cordless tools and appliances.
The US Department of Energy (DOE) has funded a variety of programs designed to encourage more rapid development of renewable energy sources. Specific research and development projects included:
- domestic manufacturing of advanced batteries
- development of improved stationary and portable fuel cell power systems
- development of commercial scale bio-refineries
- improved design of molten salt storage facilities at power plants that concentrate solar energy
- design and evaluation of parabolic troughs, dishes, and heliostats for solar power stations
- construction of demonstration facilities designed to recover and better utilize geothermal energy
All of these expanding subsectors for generating power have the potential to be important users of nickel metal and or nickel-bearing alloys.
Nickel Deposits Come in Two Forms
Nickel deposits are generally found in two forms: sulphide or laterite. About 60% of the world's known nickel resources are laterites. The remaining 40% are sulphide deposits.
Nickel Sulphide Deposits – the principal ore mineral is pentlandite (Fe,Ni)O(OH) – are formed from the precipitation of nickel minerals by hydrothermal fluids. These sulfide deposits are also called magmatic sulfide deposits. The main benefit to sulphide ores is that they can be concentrated using a simple physical separation technique called flotation. Most nickel sulfide deposits have traditionally been processed by concentration through a froth flotation process followed by pyrometallurgical extraction.