Refining
Salt that is gained through evaportation of seawater needs to be cleaned; this is done by dissloving it in brine and then forcing it to crystallize. After the process, it is no lnoger possible to distinguish it from the salt extracted from rocks, by a mining process. Depending on the country, table salt for common use as a food additive may have iodine added. Sometimes Potassium fluoride is added as well.