Millerite - NiS.

Siegenite - CoNi2S4.

Nickel is a silvery metallic element. Most of the nickel mined comes from two types of deposits. The first are laterites, in which the principal minerals are garnierite (hydrous nickel silicate) and nickeliferous limonite (hydrated iron oxide). The second are magmatic sulfide deposits, in which the principal mineral is pentlandite (iron nickel sulfide). The United States imports nearly all its primary nickel mainly from Australia, Canada, Norway, and Russia. Important uses are in alloy and stainless alloy steels, aluminum alloys, chemicals, copper alloys, electroplating, and superalloys for jet engines and industrial gas turbine components.

Background

Nickel, with a symbol of Ni, is a silvery shiny, metallic element with an atomic number of 28. It can be hammered into thin sheets, which means it is malleable. Nickel, iron and cobalt are the only three elements known to be ferro-magnetic. Of the three, nickel is the least magnetic. When all three ferro-magnetic metals are alloyed together, an unusually strong magnet is created. This alloy conducts heat and electricity fairly well, but is not as good a conductor as pure silver or copper.

In 1751, Axel Fredrik Cronstedt of Sweden attempted to extract copper from the mineral niccolite and to his surprise got a silvery-white metal, instead of the copper. He named the new metal nickel after the mineral name of niccolite. This was the first discovery of nickel in the western world, but an alloy of copper, nickel and zinc - paitung or paktong - was used in China as far back as 235 B.C.E. for utensils and other metal ware.

The presence of elemental nickel in iron-nickel meteorites distinguishes them from rocks or minerals produced in the Earth. The amount of nickel in these meteorites ranges from 5% to almost 20%. When they are sliced and etched with acid, a pattern of intergrown crystals is revealed. This is called a widmanstatten pattern. This texture of the iron-nickel meteorites suggests they cooled and crystallized very, very slowly deep inside asteroids.

Trace amounts of nickel are important to a number of species of animals. It plays a role, along with iron, in the transport of oxygen in the blood. Nickel deficiency has been shown to reduce iron uptake in young pigs.

Nickel is also important to the proper function of some enzymes in both plants and animals. Experiments on rats have shown that insufficient nickel leads to liver damage. Nickel is involved in the transmission of genetic code - DNA, RNA, etc. it is also present in certain enzymes that metabolize sugar. Oats and other whole grains are an excellent source of nickel.

Scientists who study seismic waves from earthquakes, have determined that the core of the Earth consists of a liquid outer core and a solid inner core composed of an iron-nickel mixture.

Name

From very early times nickel-bearing minerals, such as niccolite, were mixed with glass to create green glass. This was called kupfernickel which means Devil/s Copper. When nickel was extracted from niccolite, the mineral name was a logical source of the name for the element, nickel.

Sources

Although today it is not profitable to mine nickel in the U.S., small amounts of by-product nickel are being recovered from copper and palladium-platinum ores in the Western United States.

Approximately 87,000 tons of nickel is recovered annually by recycling stainless steel and other nickel-iron alloys. This represents about 39% of the nickel used each year.

It is estimated that there is about 140 million tons of nickel available in identified deposits. Eighty-four million tons, or 60 percent of the total available nickel is in laterite deposits. A deposit in which rain and surface water leached nickel-rich rock and concentrated the nickel at or near the surface of the earth is a laterite deposit. Nickel sulfide deposits contain the remaining forty percent (56 million tons).

Demand for nickel in the United States is much higher than what recycled nickel can provide, so nickel is imported into the country. Most of the imported nickel comes from Canada (40%), while the rest is imported from Norway (13%), Russia (12%), Australia (10%), and various other nations (25%).

Uses

In the United States, large amounts of nickel (42% of consumption in 2001) are used in the specialty steel industry for stainless steel and related alloys. In 1913, Harry Brearly, an English scientist, was the first to produced stainless steel, when he accidentally discovered that the addition of chromium to steel makes the steel resistant to staining. Today, stainless steel also contains some molybdenum, titanium and nickel, to increase its resistance to corrosion.

Thirty-eight percent of annual nickel use is in nonferrous alloys (or mixed with metals other than steel) and superalloys (metal mixtures designed to withstand extremely high temperatures and/or pressures, or to have high electrical conductivity). Nickel is used as a coating on other metals to slow down corrosion. Nickel coatings accounts for 14% of nickel use.

The remaining 6% of the annual nickel use is for a variety of purposes including the production of coins, nickel-cadmium and nickel-metal hydride batteries; as a catalyst for certain chemical reactions; and, as a colorant, nickel is added to glass to give it a green color. The U.S. 5-cent piece is called a "nickel" because it only contains 25% nickel. The other 75% is copper.

Rechargeable nickel-hydride batteries are widely used for cellular phones, video cameras, and other electronic devices. Nickel-cadmium batteries are used primarily to power cordless tools and appliances.

Substitutes and Alternative Sources

Manganese crusts and nodules on the ocean floor could be a valuable source of nickel someday. These deposits contain manganese and other metal ions, such as nickel. Some deposits appear to have formed when superhot liquids from deep sea volcanoes came in contact with the very cold deep ocean water causing the metals to precipitate and collect on the ocean floor. Other deposits far from subduction zones may have formed when microorganisms in the sea water accelerated the precipitation of dissolved iron and manganese. Today, it is too expensive to mine the deposits, but as the surface nickel deposits are used up, the value of nickel may increase and make it profitable to retrieve these manganese nodules.

There are a number of materials that could be used in place of nickel, but generally, these substitutes are more expensive than nickel and/or less effective. Aluminum, plastics or coated steel could be used in place of stainless steel in some situations. Titanium can be used in place of nickel to make some superalloys.