Chemistry:Base metal
A base metal is a common and inexpensive metal, as opposed to a precious metal such as gold or silver.[1] In numismatics, coins often derived their value from the precious metal content; however, base metals have also been used in coins in the past and today.[2]
Specific definitions
In contrast to noble metals, base metals may be distinguished by oxidizing or corroding relatively easily and reacting variably with diluted hydrochloric acid (HCl) to form hydrogen. Examples include iron, nickel, lead and zinc. Copper is also considered a base metal because it oxidizes relatively easily, although it does not react with HCl.
In mining and economics, the term base metals refers to industrial non-ferrous metals excluding precious metals. These include copper, lead, nickel and zinc.[3]
The U.S. Customs and Border Protection agency is more inclusive in its definition of commercial base metals. Its list includes—in addition to copper, lead, nickel, and zinc—the following metals: iron and steel (an alloy), aluminium, tin, tungsten, molybdenum, tantalum, cobalt, bismuth, cadmium, titanium, zirconium, antimony, manganese, beryllium, chromium, germanium, vanadium, gallium, hafnium, indium, niobium, rhenium, and thallium, and their alloys.[4]
Other uses
In the context of plated metal products, the base metal underlies the plating metal, as copper underlies silver in Sheffield plate.
See also
References
- ↑ Oxford dictionary definition of "base metal"[|permanent dead link|dead link}}] oxforddictionaries.com.
- ↑ "Introduction to Numismatic Terms and Methods". http://numismatics.org/seminar/termsmethods/.
- ↑ "Base Metal and Iron Ore Mining, Pollution Prevention and Abatement Handbook. WORLD BANK GROUP 1998". http://responsiblemining.net/pubs/WB_BaseMetalAndIronJul98.pdf.
- ↑ What Every Member of the Trade Community Should Know About: Household Articles of Base Metal, U.S. Customs and Border Protection. Jan. 2010
External links
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