SQM's Sodium Nitrate and Potassium Nitrate

The natural solution for thermal storage and heat transfer.

SQM's thermo-solar salts, a mixture of Sodium Nitrate and Potassium Nitrate, allow CSP plants to compete with conventional fossil-fuelled plants and nuclear power plants, since they can also operate 24/7 to match electricity output and demand.

Annually, SQM produces around 1 million MT (more than 50% of the world market quantities!) of sodium and potassium nitrate from Caliche Ore and Salar Brines, two natural resources found in Northern Chile. Caliche is extracted from surface deposits in the Atacama Desert; derived products including Sodium Nitrate and Iodine. The Salar Brines are pumped from underground brines in the Salar de Atacama (Atacama Salt Flat) after which they are deposited in large solar evaporation ponds to separate the desired elements. Products derived from Salar Brines include Lithium Chloride Brine, Potassium Chloride, Magnesium Chloride Hexahydrate, Boric Acid and Potassium Sulphate.

To produce nitrates, the caliche mineral is crushed and then subjected to a leaching process with water. Sodium Nitrate is obtained from this leached solution by crystallization. Part of the obtained Sodium Nitrate goes through another stage of processing during which Potassium Chloride, from the Salar de Atacama is added. The mixture is then subjected to ion exchange, crystallization, refining and drying processes to yield Potassium Nitrate. Control of stoichiometry of the reaction and crystallization process allows for a controlled mix of Sodium Nitrate and Potassium Nitrate.