Potash is the term commonly used to refer to the nutrient forms of the element potassium (K). Potassium is plentiful in nature and is required for many of the vital functions that occur in plants, animals and humans. Potash is a vital fertilizer for the worlds food supply.
Clay minerals, rain and sea water all contain K. There are sizeable potash bearing rock deposits in many regions of the world originating from minerals in oceans that evaporated millions of years ago. Most potash fertilizer comes from one such potash rock, sylvinite, which requires only separation from salt and other minerals and then suitable preparation for use in fertilizers.
Conventional underground mining using large boring and mining machines is the most common method of potash mining today accounting for a majority of global potash capacity. The mined ore is transported by conveyors to the surface to be milled. Another potash mining method is solution mining whereby heated brine (a solution of salt in water) is injected to extract potash from underground ores. The potash-rich brine is pumped to surface ponds from which the potash is extracted. The extracted potash ore is then milled – the ore is crushed into small pieces to release potash and salt crystals, and agitated to separate the crystals from clay particles which are then removed using size separators.