The most valuable rocks are ores. These rocks contain minerals or metals that can be of great commercial value, such as gold, platinum, copper, iron, nickel or silver.Continue Reading
Some elements are found in more than one type of rock, and some rocks contain more than one type of element. Galena, for example, is a major source of lead, but it can also contain silver.
Nickel, a silvery white, shiny metal that has leant its name to an American coin, is found in limonite, which also contains iron. Another nickel ore is pentlandite, which contains iron as well as small amounts of cobalt.
Iron, which is strong, ductile and malleable, is one of the most sought after metals and is inexpensive because it's abundant. This is true even though iron is such a reactive element that it's rarely found in its free state. Among the ores of iron besides those mentioned are hematite, goethite and magnetite. The Earth's core is made of iron, and it's even found in meteors in the form of siderite.
Copper is also found in many types of rocks, especially rocks that are abundant in carbonates, oxides and sulphides. These ores include rocks that have their own esthetic value such as malachite, cuprite and azurite.Learn more about Geology
Iron ores in the form of hematite (ferrous oxide) and magnetite are removed from the earth through mining. The use of heavy mining equipment is necessary to dig out large pits in an area with a large deposit of iron ore; however, because iron does not occur naturally, it is necessary to use a blast furnace to separate or refine iron from the other substances in the iron ore.Full Answer >
As with most ores, mercury recovery is achieved through underground mining. The mercury is conventionally mined and blasted and then scraped or mechanically loaded onto ore cars.Full Answer >
Metal extraction from ores occurs in many different ways involving physical, chemical and electrical means. Even ores of the same metal sometimes require different methods of separation depending on the concentration of the metal and its chemical composition within the ore.Full Answer >
Nickel is extracted from ores via the Mond process, in which nickel oxides are purified through multiple steps into pure nickel metal. It is placed with hydrogen and carbon monoxide gases at 122 degrees Fahrenheit, which converts it to impure nickel. This impure nickel then reacts with the carbon monoxide, becoming nickel tetracarbonyl. This is then heated to 446 degrees Fahrenheit, which releases the carbon monoxide gas and leaves pure nickel metal.Full Answer >