Cadmium (symbol Cd) is a soft, bluish-white, metallic element that can easily be shaped and cut with a knife. Cadmium melts at 321 degrees Celsius and boils at 765 degrees Celsius. Cadmium burns brightly in air when heated, forming the oxide CdO. In 1871, the German chemist Friedrich Stromeyer discovered cadmium in incrustations in zinc furnaces.
Rare greenockite is the only mineral bearing cadmium. Cadmium occurs most often in small quantities associated with zinc ores, such as sphalerite. Electrolysis or fractional distillation is used to separate the cadmium and zinc. About 80% of world cadmium output is a by-product from zinc refining. The remaining 20% comes from secondary sources and recycling of cadmium products. Cadmium recycling is practical only from nickel-cadmium batteries and from some alloys and dust from electric-arc furnaces.
Cadmium is used primarily for metal plating and coating operations in transportation equipment, machinery, baking enamels, photography, and television phosphors. It is also used in pigments and lasers, and in nickel-cadmium and solar batteries.
Prices - Cadmium prices for the 8 years up to 2005 were at severely depressed levels, reflecting the decreased demand for the substance. In 2005, however, cadmium prices rose very sharply by +172.7% to $1.50 cents per pound. Then in 2006 the price fell 10.0% to $1.35 per pound. Still, that was far above the record low of 14 cents in 1999 and not far below the 20-year average of about $1.60 per pound. The record high of $6.91 per pound was posted in 1988.
Supply - World cadmium production in 2006 fell 2.0% yr/yr to 19,300 metric tons, but still up from the 23-year low of 17,800 metric tons in 2002. The largest producer was China with 16% of total world production followed by Japan with 12%. U.S. production of cadmium in 2006 fell 52.4% yr/yr to a record low of 700 metric tons. The U.S. in 2006 accounted for 3.6% of world cadmium production.
Demand - Consumption of cadmium has been declining fairly steeply in the last few years due to environmental concerns. U.S. cadmium consumption fell by 19.7% yr/yr in 2006 to 561 metric tons, which was a 10-decade low. Of the total apparent consumption, about 75% is used for batteries, 12% for pigments, 8% for coatings and plating, 4% for nonferrous alloys, and 1% for other uses.
Trade - The U.S. in 2006 relied on imports for 29% of its cadmium usage, down from 38% as recently as 1996. U.S. imports of cadmium plunged over the past 10 years but recovered to post a 6-year high in 2005 at 288 metric tons. That, however, was still far below the 1,110 metric tons seen as recently as 1994. Then, in 2006 imports resumed their decline and fell 37.5% to 180 metric tons. U.S. exports of cadmium in 2006 fell sharply by 29.6% to 483 metric tons.