Calcium strontium or barium, the oxide–nitride coating that results in air is stable and lathe machining and other standard metallurgical techniques are suitable for calcium. In the United States and Canada, calcium is instead produced by reducing lime with aluminium at high temperatures. Calcium provides a link between tectonics, climate, and the carbon cycle. In the simplest terms, uplift of mountains exposes calcium-bearing rocks to chemical weathering and releases Ca into surface water. These ions are transported to the ocean where they react with dissolved CO to form limestone (), which in turn settles to the sea floor where it is
Calcium nitrate nitrate tetrahydrate is highly endothermic (cooling). For this reason, calcium nitrate tetrahydrate is sometimes used for regenerable cold packs. Calcium nitrate can be used as a part of molten salt mixtures. Typical are binary mixtures of calcium nitrate and potassium nitrate or ternary mixtures including also sodium nitrate. Those molten salts can be used to replace thermo oil in concentrated solar power plants for the heat transfer, but mostly those are used in heat storage. Calcium nitrate Calcium nitrate, also called "Norgessalpeter" (Norwegian saltpeter), is an inorganic compound with the formula Ca(NO). This colourless salt absorbs moisture from the air