Sulphur is used in fertilizers, normally in the form of ammonium sulphate, where there is a deficiency of sulphur in the soil.
Sulphur is also used to make sulphuric acid from sulphur dioxide. Sulphur dioxide is used to make dyes and as a bleaching agent.
Sulphur has a pale yellow appearance and has a slight odour of rotten egg. It is insoluble in water, but soluble in carbon disulphide.
It is found in meteorites, volcanoes, hot springs, and as galena, gypsum, Epsom salts and barite. It is also a minor constituent of fats, body fluids and skeletal minerals.
There are two key sources of processing sulphur. The first is the Frasch process, where sulphur is extracted from underground without mining it.
In the Frasch process, underground deposits of sulphur are forced to the surface using superheated water and steam (to melt the sulphur) and compressed air. This gives molten sulphur, which is allowed to cool in large basins. Purity can reach 99.5%. The process is energy intense.
Another source of sulphur is as a by-product of processing crude oil and natural gas, which contain hydrogen sulphide. It is produced in crush lump, flake and prilled form.
Key industrial uses of sulphur includes production of black gunpowder, asphalt, vulcanisation of natural rubber, as a fungicide and as a fumigant, use in the bleaching of dried fruits and for paper products.