Salt (chemical name: sodium chloride - NaCl) is composed of ions, which are electrically-charged atoms formed when the elements sodium and chlorine bond.
During the reaction, the sodium atoms become positively-charged sodium ions (Na+) and the chlorine atoms become negatively charged chloride ions (Cl-). Each sodium ion is surrounded by six chloride ions to form a perfect symetrical crystal. As opposites attract the bonds are very tight. If salt is heated to more than 800°C, the strong bond between the individual ions weakens and the crystal melts.
If salt is added to water, the water molecules push their way between the ions and weaken the electrical attraction - the crystal dissolves.
Learn more about crystal structures on wikipedia.org
How we dig the salt up
Huge machines with sharp rotors tunnel their way through the rock salt. An automatic electrohydraulic drilling machine drills rows of holes about 14 meters deep into the ceiling. They are then filled with explosives which are detonated once all the workers leave the mine. The crushed rock salt is then transported by conveyor belt to the shaft where it is sent to the surface.
Germany is one of the world's main sources of salt. The country boasts one of the largest salt mines in Europe which is located in Borth. Subterranean deposits are estimated at more than 200,000 million tonnes.
Another method of extracting salt is to pour hot water into underground salt plugs. The salt dissolves and the brine is pumped to the surface. The advantage of this method is that the extraction process can be regulated so that many of the impurities in the salt remain underground. The brine is concentrated by evaporation in large vacuum plants, yielding 99.9% pure salt.
As it is an essential ingredient in producing chlorine, we work closely with the European salt industries and as of April 2016, the non-profit European salt producers trade association EU Salt is part of the Euro Chlor family.