Nick Beyer, age 15, of Casper, WYO.$ for his question:
WHERE DO WE FIND CHROMIUM?
Chromium is a hard, brittle, metallic element. It does not occur in nature as an uncombined metal. It is a chemical element that is usually combined with iron and oxygen in a mineral called chromite.
Chromite is mined in Cuba, the Philippines, New Caledonia, the U.S.S.R., Zimbabwe, Albania, South Africa and Turkey.
Almost no chromite is mined in the United States, although an extensive deposit of the mineral has been found in Montana.
Chromium takes its name from the Greek word °chroma,' which means color. This name was selected because chromium compounds are very colorful.
The element of chromium was discovered in 1797 by a French chemist named N.L. Vauquelin. He found it in a sample of the mineral crocoite.
Chromium is usually taken from chromite by heating the mineral in the presence of carbon or aluminum.
Chromium is perhaps best known for its use in the trimming found on automobiles. And because of its strength, brightness, luster and resistance to corrosion, chromium is a perfect material to use as a coating for other metals. A thin layer of chromium is often electroplated over the other metal. Sometimes the layer is as thin as one ten thousandth of an inch.
When chromium is added to steel, it helps to make the steel resistant to corrosion and oxidation. Steels that contain at least 10 percent chromium are called stainless steels.
The metal used in the decorative trimming on automobiles and trucks is steel with up to 18 percent chromium added.
Many eating and kitchen utensils are made of stainless steel because it is durable, good looking and easy to keep clean.
Chromium compounds are used in certain paints as coloring agents. Chrome yellow and chrome green are two favorites. Compounds are also used in dyeing cloth, in tanning leather and in photography.
Chromium is steel gray in color. It is lustrous, hard, brittle and it takes a very high polish. It melts at about 3,434 degrees Fahrenheit.
Chromium steel alloys, or mixtures, are used to make armor plate for ships and tanks, safes, ball bearings and the cutting edges of high speed machine tools.
Compounds of chromium are used in the textile industry as mordants, or substances that fix dyes permanently to fabrics. They are also used in the aircraft industry to anodize aluminum, or to coat the metal with a thick, protective oxide film.
Chromium has a chemical symbol of Cr. Its atomic number is 24 and its atomic weight is 51.996.