Nickel
A silvery-white metal with a slight golden tinge, nickel stands as one of only four elements that remain ferromagnetic at room temperature. The other three are iron, cobalt, and gadolinium. Its Curie temperature sits at 354 degrees Celsius, meaning bulk nickel loses its magnetic properties above this point. The unit cell of nickel forms a face-centered cube structure with a lattice parameter of 0.352 nanometers. This crystal arrangement remains stable under pressures reaching at least 70 gigapascals. Nickel possesses high electrical and thermal conductivity for a transition metal. It is hard yet malleable and ductile enough to be drawn into wires or hammered into sheets. Ideal crystals theoretically possess a compressive strength of 34 gigapascals. Real-world bulk material never achieves this theoretical limit due to the formation and movement of dislocations within the atomic lattice. However, researchers have successfully reached this strength in nickel nanoparticles.
Most nickel on Earth resides deep within the planet's outer and inner cores. Kamacite and taenite form naturally occurring alloys of iron and nickel found in meteorites. Kamacite usually maintains an alloy ratio between 90 parts iron and 10 parts nickel. Taenite contains anywhere from 20 percent to 65 percent nickel. These minerals also appear within terrestrial rocks known as ultramafic types. Identified land-based resources averaging one percent nickel or greater total over 130 million tons globally. About 60 percent exists in laterite deposits while 40 percent lies within sulfide deposits. The largest producers include Indonesia with 2.2 million tonnes annually. Russia follows with 210,000 tonnes and Canada contributes 190,000 tonnes. Extensive sources exist in the Clarion Clipperton Zone of the Pacific Ocean. Polymetallic nodules pepper the seafloor at depths between 3.5 and 6 kilometers below sea level. These nodules contain approximately 1.7 percent nickel mixed with rare-earth metals.
Unintentional use of nickel traces back to 3500 BCE in bronze artifacts from Syria containing up to 2 percent nickel. Ancient Chinese manuscripts mention white copper used between 1700 and 1400 BCE. Baron Axel Fredrik Cronstedt first isolated and classified the element in 1751. He worked at a cobalt mine in the village of Los, Sweden. Miners had previously blamed a mischievous sprite named Nickel for their inability to extract copper from certain ores. They called this ore kupfernickel, meaning Nickel's copper. Cronstedt produced a white metal instead of copper and named it after the spirit. Coins made of pure nickel appeared in Switzerland starting in 1881. The United States Mint introduced the five-cent shield nickel in 1866 with an alloy of 25 percent nickel and 75 percent copper. This specific proportion is not ferromagnetic unlike earlier versions.
Nickel extraction relies on pyrometallurgical techniques or hydrometallurgical methods depending on the ore type. Most sulfide deposits undergo concentration through froth flotation before pyrometallurgical extraction. The Sherritt-Gordon process removes copper by adding hydrogen sulfide to leave a concentrate of cobalt and nickel. Solvent separation then distinguishes the two metals with final purity exceeding 86 percent. Leaching involves dissolving metal matte into a salt solution followed by electrowinning onto a cathode. Ludwig Mond patented the Mond process before the beginning of the 20th century. This method treats nickel oxide with carbon monoxide at temperatures between 40 and 80 degrees Celsius. A sulfur catalyst facilitates the formation of volatile nickel carbonyl gas. Tens of thousands of nickel spheres stir inside large chambers where decomposition deposits pure metal. Alternative processes decompose the carbonyl in smaller chambers at 230 degrees Celsius to create fine powder. The resulting product achieves over 99.99 percent purity known as carbonyl nickel.
Global production reaches approximately 3.7 million tonnes annually across major producing nations. About 68 percent of world output goes toward stainless steel manufacturing. Ten percent serves nonferrous alloys while nine percent supports electroplating operations. Seven percent enters alloy steels and three percent fills foundry needs. Four percent covers other applications including rechargeable batteries for electric vehicles. The market price fluctuates wildly based on geopolitical events and supply constraints. In early 2007, trading reached US$52,300 per tonne before falling to $11,000 later that year. During the 2022 Russian invasion of Ukraine, prices quadrupled within two days reaching US$100,000 per tonne. The London Metal Exchange cancelled contracts worth $3.9 billion and suspended trading for over a week. Analyst Andy Home noted such shocks stem from purity requirements limiting commodity availability. Only Grade I metal with 99.8 percent purity qualifies for exchange trading. Most global supply exists in ferro-nickel alloys or lower-grade purities unsuitable for direct exchange use. Average pricing in 2024 settled at $15,328 per metric ton.
Nickel plays an essential role in enzymes for certain plants bacteria archaea and fungi. Urease catalyzes hydrolysis of urea into ammonia and carbamate within these organisms. NiFe hydrogenases facilitate oxidation of carbon monoxide to form protons and electrons. A nickel-tetrapyrrole coenzyme called cofactor F430 appears in methyl coenzyme M reductase. This enzyme catalyzes methane formation in methanogenic archaea during the Permian-Triassic extinction event. Dietary intake averages between 70 and 100 micrograms daily with less than 10 percent absorption. Relatively large amounts leach into food cooked in stainless steel containers. One serving of tomato sauce after ten cooking cycles contains approximately 88 micrograms of nickel. The US Institute of Medicine has not confirmed nickel as essential for humans. No Recommended Dietary Allowance exists for human consumption. Tolerable upper intake levels stand at one milligram per day for soluble salts. Nickel compounds classified as human carcinogens based on respiratory cancer risks observed in ore refinery workers. Inhalation exposure limits set by OSHA reach one milligram per cubic meter over eight hours. Sensitized individuals develop contact dermatitis from skin exposure to jewelry or coins.
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Common questions
What is the Curie temperature of nickel?
The Curie temperature of nickel sits at 354 degrees Celsius. Bulk nickel loses its magnetic properties above this point.
When was nickel first isolated and classified by Baron Axel Fredrik Cronstedt?
Baron Axel Fredrik Cronstedt first isolated and classified the element in 1751. He worked at a cobalt mine in the village of Los, Sweden.
How much nickel does Indonesia produce annually?
Indonesia produces 2.2 million tonnes of nickel annually. It stands as one of the largest producers alongside Russia and Canada.
What percentage of global nickel output goes toward stainless steel manufacturing?
About 68 percent of world output goes toward stainless steel manufacturing. Ten percent serves nonferrous alloys while nine percent supports electroplating operations.
Why are nickel compounds classified as human carcinogens?
Nickel compounds are classified as human carcinogens based on respiratory cancer risks observed in ore refinery workers. Inhalation exposure limits set by OSHA reach one milligram per cubic meter over eight hours.