Se refiere al proceso de purificación de la sal (mediante flotación) para uso en la industria química y para consumo humano

Ejemplos:

Flotation. In many types of rock salt the impurities (anhydrite, insolubles) are dispersed throughout the crystalline salt. The final product quality attainable by flotation therefore depends not only on salt grinding, and thus on minerals separation, but also on removal of the impurities with the foam product, which is influenced by the used flotation reagents. Selective separation of anhydrite from fine-ground rock salt requires grinding to 250 mm and the use of sulfated fatty acids. Sulfate contents of 500 ppm in the final product are achievable. Disadvantages of salt flotation result from the very fine grains, which can be hard to debrine and require additional effort during later production of brine. Attention must be paid to the complicated handling of the flotated salt and its residual flotation reagents, and a suitable possibility for disposal of the tailings must be available...

http://www.fisme.science.uu.nl/toepassingen/28147/documents/...

Flotation was the only unit operation that was promising. Flotation takes place in the SALEX process naturally. Krebs Swiss only had to enhance the natural flotation with suitable reagents. In search for reagents, they came across a potash mine with a plant for salt flotation. The flotated salt was used by chloralkali producers using mercury and membrane cells...
http://www.salt-partners.com/pdf/Purification of salt IM96.p...