The recovery of sodium chloride from sea water

The recovery of sodium chloride from the sea has been practised since ancient times. Modern knowledge of phase rules enables us to recover fairly clean sodium chloride from sea water, which consists of a complex mixture of salts and other minerals. According to quality requirements, two procedures can be applied; solar pre-concentration of the sea water with subsequent vacuum distillation, or solar pre-concentration with subsequent over-saturation and precipitation of the salt. The individual product requirements and cost factors have to be diligently studied in order to decide which procedure is the more feasible.