Topic summary
Salterns

Extracted from the Wikipedia article Saltern.
Salterns usually begin with seawater as the initial source of brine but may also use natural saltwater springs and streams. The water is evaporated, usually over a series of ponds, to the point where sodium chloride and other salts precipitate out of the saturated brine, allowing pure salts to be harvested. Where complete evaporation in this fashion was not routinely achievable due to weather, salt was produced from the concentrated brine by boiling the brine.