Calcium nitrate salt" 5Ca(NO).NHNO·10HO. This is called calcium ammonium nitrate. Formulations lacking ammonia are also known: Ca(NO)·4HO (11.9-0-0 + 16.9 Ca) and the water-free 17-0-0 + 23.6 Ca. A liquid formulation (9-0-0 + 11 Ca) is also offered. An anhydrous, air-stable derivative is the urea complex Ca(NO)·4[OC(NH)], which has been sold as Cal-Urea. Calcium nitrate is also used to control certain plant diseases. For example, dilute calcium nitrate (and calcium chloride) sprays are used to control bitter pit and cork spot in apple trees. Calcium nitrate is used in waste water pre-conditioning for odour emission prevention. The waste water pre-conditioning is based
Calcium apatite ([Ca(PO)F]). The major producers of calcium are China (about 10000 to 12000 tonnes per year), Russia (about 6000 to 8000 tonnes per year), and the United States (about 2000 to 4000 tonnes per year). Canada and France are also among the minor producers. In 2005, about 24000 tonnes of calcium were produced; about half of the world's extracted calcium is used by the United States, with about 80% of the output used each year. In Russia and China, Davy's method of electrolysis is still used, but is instead applied to molten calcium chloride. Since calcium is less reactive than