Potash or potassium salts are produced through two primary sources; brines and evaporite deposits. The two most common and economically important potassium sources are sulfate of potash (K2SO4 – SOP) and muriate of potash (KCl – MOP). Evaporite deposits are usually quite deep, and are either mined through underground mining or in-situ solution mining. The processing thus depends on the mining method but can consist of leaching of impurities, flotation and crystallisation. Brine potash sources are harvested by depositing the brine in solar evaporation ponds, different salts crystallise at different times depending on their solubility and the initial composition of the brine. Brines can be processed this way, or through bulk evaporation and flotation of the combined salt mixture.
MOP and SOP are both used as fertiliser with SOP being a premium product due to not containing chlorides and hence is suitable for chloride sensitive crops such as tobacco, fruits and vegetables. MOP is cheaper and hence is used as a broad acreage fertiliser.