Production Processes
We have the technological development and proven experience to carry out highly efficient production processes in each of our lines of business.
En At SQM we produce sodium and potassium nitrate from brines and caliche, two natural resources found in Northern Chile. Caliche is extracted from deposits found on the surface in Atacama Desert, from which sodium nitrate and iodine are obtained. Brines are obtained from the subsoil on Atacama Salt Flats, which are deposited in solar evaporation ponds.
The caliche overload is removed with bulldozers. Subsequently, explosive changes are used to break up the ore, which is then placed on trucks by front-end loaders. At Pedro de Valdivia, trucks haul and accumulate the ore on piles or stockpiles near temporary railroad stations, where it is loaded onto wagons to be transported back to the plant.
In the case of Maria Elena, Nueva Victoria and Pampa Blanca (located in Sierra Gorda), the ore is leached in heaps, obtaining solutions destined primarily for iodine production.
After this process, they are transported to solar evaporation ponds, where salts with a high concentration of nitrate are crystallized and transported by truck to plants located in Coya Sur, where they are used as material for potassium nitrate production.
At these plants, the caliche is mechanically ground to approximately one-half inch. It is then transferred to a leaching plant with washing pans in order to extract its nitrate and iodine contents.
The brines extracted from the Atacama Salt Flats are deposited in solar evaporation ponds from which concentrated brines and salts are obtained using solar energy.
Las The concentrated brines are re-injected into subterranean salt deposits. The salts deposited in the evaporation ponds are duly collected and transported. Potassium Chloride, Potassium Sulfate and Boric Acid are obtained by grinding, floating, drying and compacting.
The solutions that result from the leaching of the caliche mineral in the plants of Pedro de Valdivia, Maria Elena and Nueva Victoria are used to produce Iodine from the iodate contained in them. The variations in the contents of iodine and other chemical components in the treated mineral, besides of the other operational parameters, require a high specific level of knowledge to handle the process in an efficient way. The solutions of caliche bleaching contain iodine in the form of iodate. Part of the iodate in the solution is reduced to iodide using sulfur dioxide which is produced when sulfur is burnt. The resulting iodide is combined with the rest of the original solution of iodate to free the elemental iodine. Then, the solid iodine is refined through a process of foundry and prill. In SQM we have obtained licenses in Chile and the United States for the processing of iodine prill.
