Some 99 percent of the world’s chromite is found in southern Africa and Zimbabwe. Chemical and metallurgical industries for example in the U.S. use about 85% of the chromite consumed.
Chromium is a hard, bluish metallic element Cr with an atomic number of 24. In the mid-1700’s, chemical analysis of a mineral from Siberia showed that it contained lead. This mineral, Crocoite (PbCrO4, lead chromate), was known as “red lead” because of the beautiful orange-red color of its crystals. It also contained another, then-unknown material. This material was identified as chromium trioxide (CrO3) by Louis-Nicholas Vauquelin. In 1797, he heated this oxide with charcoal to remove the oxygen (chemists call this reaction a reducing process) which left the metal chromium.
Shortly after Vauquelin’s discovery, a German chemist name Tassaert discovered chromium in an ore that geologists now call Chromite (FeCr2O4, ferrous chromic oxide). Chromite (chromium ore) forms in an igneous environment.
Chromium is alloyed (that is, mixed) with steel to make it corrosion resistant or harder. An example is its use in the production of stainless steel, a bright, shiny steel that is strong and resistant to oxidation (rust). Stainless steel production consumes most of the chromium produced annually. Chromium is also used to make heat-resisting steel. So-called “superalloys” use chromium and have strategic military applications.
Chromium also has some use in the manufacture of certain chemicals. For example, chromium-bearing chemicals are used in the process of tanning leather. Chromium compounds are also used in the textiles industries to produce a yellow color.
Substitutes and Alternative Sources
There is no good alternative for chromium in the manufacture of steel or chromium chemicals. Scrap metal that contains chromium can be recycled as an alternative source. The natural abundance of chromite in the Earth’s crust makes alternative sources unnecessary at this time.
The only ore of chromium is the mineral chromite. U.S. chromium consumption is equivalent to about 14% of all the chromite ore mined each year. In the western hemisphere, chromite ore is produced only in Brazil and Cuba; the U.S., Mexico and Canada do not produce chromite. (The Stillwater Complex in Montana is the biggest chromium deposit in the United States). By comparison, about 80% of world production of chromite comes from India, Kazakhstan, Turkey and southern Africa. Southern Africa itself produces about half of this.
Geologists estimate that there are about 11 billion tons of chromium ore (chromite) in the world that could be mined. Most of these resources are found in southern Africa. This is enough chromium ore to meet world demand for hundreds of years into the future.