CadiumChemical symbol Cd. Cadium is produced primarily as a by-product of zinc refining, but also is recovered during the benefication and refining of some lead ores and complex copper-zinc ores. Cadmium is bluish-white soft metal that can be cut with a knife. The principal use of cadmium, which was discovered in Germany in 1817, has been in nickel-cadmium batteries for personal, portable communications, electronic and electrical equipment. Other applications include pigments, coatings and plating, stabilizers for plastics and similar synthetics, alloys, lasers and solar cells.