<P> Four inorganic compounds are used as iodide sources, depending on the producer: potassium iodate, potassium iodide, sodium iodate, and sodium iodide . Any of these compounds supplies the body with its iodine required for the biosynthesis of thyroxine (T) and triiodothyronine (T) hormones by the thyroid gland . Animals also benefit from iodine supplements, and the hydrogen iodide derivative of ethylenediamine is the main supplement to livestock feed . </P> <P> Salt is an effective vehicle for distributing iodine to the public because it does not spoil and is consumed in more predictable amounts than most other commodities . For example, the concentration of iodine in salt has gradually increased in Switzerland: 3.75 mg / kg in 1952, 7.5 mg / kg in 1962, 15 mg / kg in 1980, 20 mg / kg in 1998, and 25 mg / kg in 2014 . These increases were found to improve iodine status in the general Swiss population . </P> <P> Salt that is iodised with iodide may slowly lose its iodine content by exposure to excess air over long periods . </P> <P> Edible salt can be iodised by spraying it with a potassium iodate or potassium iodide solution . 57 grams of potassium iodate, costing about US $1.15 (in 2006), is required to iodise a ton of salt . Dextrose is added as a stabilizer to prevent potassium iodide from oxidizing and evaporating . Anti-caking agents such as calcium silicate are commonly added to table salt to prevent clumping . </P>

Most of the salt produced in australia is used for which purpose