Cadmium is a chemical element, which was discovered in 1817
AD by a German chemist Friedrich Stromeyer
, while he was working on zinc and its impurities. Cadmium was named after the Greek god Cadmus. According to Greek mythology, Cadmus had an adventurous life around 2000 BC. The present article tells you about the uses of cadmium.Facts About Cadmium
► Cadmium is a rare, transition metallic element with the symbol 'Cd'. It is found in Group IIB of the periodic table.Uses of Cadmium
► Its atomic number and relative atomic mass are 48 and 112.40 respectively. It is a fairly abundant element.
► It is soft to the touch and bluish-white in color. Cadmium is a ductile metal which melts at 320 degree centigrade.
► It undergoes slow oxidation in moist air. Cadmium burns on being heated. Cadmium prefers an oxidation state of +2 in majority of its compounds.
► It finds resemblance with two other metals in group 12. They are zinc and mercury. Alike mercury, it shows a low melting point when compared to other transition metals.
► Pure cadmium is rarely found in nature. It is often found in association with other elements like zinc, copper and lead.
► Cadmium is present in abundance in zinc ores and in Greenockite (CdS). Cadmium is separated from zinc and other elements by repeated distillation of its ores. It is also produced by precipitates obtained from the liquors, during the electrolyte refining of zinc.
► Cadmium and its compounds are toxic in nature. Therefore, a health condition called Cadmium poisoning is observed in those who have prolonged exposure to cadmium.
► It is not abundant in its native state, and therefore, could be found in many zinc ores.
► The element cadmium's uses are numerous. Cadmium is one of the byproducts of the primary non-ferrous industry.
► It has several unique and remarkable characteristics. Some of them are great resistance to corrosion, excellent electrical conductance, low melting point and its excellent resistance to chemicals and high temperatures.
► Scientists and engineers have been able to make use of these unique properties of cadmium in several important industrial applications.
► Cadmium is used in electroplating, which is the process of coating metal by making use of an electric current. Electroplating accounts for more than 60% of cadmium use.
► It is used in bearing alloys which has great resistance to fatigue and low coefficients of friction. Cadmium is widely used in electronic items.
► It is mostly used in the form of cadmium sulfide, which is a photosensitive material. It is used in black and white television phosphors as well as in the green and blue phosphors of color television tubes.
► Cadmium is used in the Weston standard voltaic cell. It forms a number of salts. Cadmium sulfide is used as a yellow pigment.
► There are numerous ways in which small amounts of cadmium are used. Thin films of cadmium telluride or cadmium sulfide are used in photovoltaic cells to covert light energy into electrical energy.
► Cadmium mercury telluride is a semiconductor for infrared imaging technique in various research applications. Cadmium salts of organic acids are used as catalysts in the generation of a wide variety of organic products.
► Alloys containing silver-indium-cadmium are used in control rods which are used in pressurized water reactors in nuclear power generation. The rods absorb free neutrons, and thus are able to control the process.
► Another cadmium use in the field of engineering is in the form of sheets which are used for shielding by similar neutron absorption.
Cadmium and its compounds are mostly considered as carcinogenic by most health and safety agencies. When ingested, it irritates the internal organs such as lungs and intestines. Cadmium poisoning is an occupational hazard. People are exposed to cadmium while working on the element, or through the air and water polluted with it. Its long term exposure can even lead to death. Once cadmium has polluted an area, it is difficult to remove it. This is a major issue in areas where it is mined and processed.