Natural Occurrence and Commercial Preparation Nearly all
chemical compounds that contain either sodium or chlorine are
ultimately derived from salt. Salt is widely and abundantly
distributed in nature. It makes up nearly 80% of the dissolved
material in seawater, and is the greater part of dissolved
matter in the Dead Sea, the Great Salt Lake, and in salt wells
in various parts of the world. It is also widely distributed in
solid form. The mineral halite is pure salt. Rock, or mineral,
salt is usually less pure; it is found in large deposits in the
United States, notably in New York, Michigan, Ohio, Kansas,
Texas, and Louisiana, and also in Great Britain, France,
Germany, Russia, China, and India. The manufacture and use of
salt is one of the oldest chemical industries. Salt is mined
from deposits or is obtained as a brine by introducing water
into the deposits to dissolve the salt and then pumping the
solution to the surface. Salt is also obtained by evaporation of
seawater, usually in shallow basins warmed