THE HISTORY OF SALT
Most people recognize the mineral halite as plain old salt; that white granular food seasoning found in a salt shaker on virtually every dining table. In fact, salt is involved in almost all aspects of human activity. Throughout history, salt (sodium chloride, NaCl) has been such an important element of life that it has been the subject of much folklore. The use of salt in everyday life has been important enough that information about how to use it has been passed down from generation to generation. In case your grandmother never passed her "salt secrets" along to you, you can use this link to discover a few of them.
Salt is an essential element in the diet of not only humans but of animals, and even of many plants. It is one of the most effective and most widely used of all food preservatives. Its industrial and other uses are almost endless. Salt has even served as money at various times and places, and it has been the cause of bitter warfare.
How long has salt been an important element of our lives? About 2,700 years B.C.- 4,700 years ago- the PENG-TZAO-KAN-MU was published in China. It is the earliest known treatise on pharmacology and a major portion of it was devoted to a discussion of more than 40 kinds of salt including descriptions of two methods of extracting and manufacturing salt that are amazingly similar to processes used today.
Salt was exchanged for slaves in ancient Greece giving rise to the expression, "not worth his salt." Roman soldiers were provided with salt rations known as "salarium argentum," the forerunner of the English word "salary." More than 30 references to salt can be found in the Bible.
The military and political significance of salt in history should not be overlooked. Napoleon's troops died during his retreat from Moscow because their wounds would not heal as a result of a lack of salt. And in 1777, the British Lord Howe was jubilant when he succeeded in capturing General Washington's salt supply.
Throughout history, because of its essential role in our lives, salt has been subjected it to governmental monopoly and special taxes. Salt taxes long supported British monarchs and thousands of Britishers were imprisoned for smuggling salt. French kings developed a salt monopoly by selling exclusive rights to produce it to a favored few who exploited that right to the point where the scarcity of salt was a major contributing cause of the French Revolution. In 1931, Mahatma Ghandi defied British salt laws as a means of mobilizing popular support for self-rule in India.
HISTORY OF SALT IN THE UNITED STATES
From the very beginning of settlement of "The New World", salt has played a prominent role in American history. The first patent issued by the British crown to an American settler was to Samuel Winslow of the Massachusetts Bay Colony for the exclusive right for ten years to make salt using his particular method.
But even earlier reports from Onondaga, New York in 1654, indicated the Onondaga Indians made salt by boiling brine from salt springs. Colonial Americans were making salt by boiling brine in iron kettles during the time the U.S. Constitution was drafted. By the time of the Civil War, 3,000 workers produced over 225,000 short tons of salt by boiling. Settlers reported that native Americans made salt at Kanawha, West Virginia before 1755, by boiling brine from salt springs. Large scale salt production from brine springs was underway by 1800, and the process of drilling for more concentrated brine began within a few years. Kanawha valley production peaked during the Civil War when it supplied the Confederacy with salt.
Similar events occurred at Avery Island, Louisiana. Historians believe that native Americans produced salt from salt springs more than 500 years before the arrival of Europeans. Salt produced by boiling brine supplied salt during The War of 1812. Full scale production in open pits or quarries began in 1862, during the Civil War, and the first underground salt mine was started in 1869, with the sinking of a shaft.
Salt played an important role in the exploration of the western United States. A detail from the Lewis and Clark Corps of Discovery was assigned to make salt for use in curing meat during the winter of 1805, which the Corps spent at Fort Clatsop located on the south side of the Columbia River in what is today the state of Oregon.
Solar salt was produced during the early 1800's in less than ideal climates, by building movable, covered sheds over the evaporating pans, protecting the salt and brine from precipitation. Solar salt making began on San Francisco Bay, California in 1770, and at the Great Salt Lake in Utah in 1847. During the 1830's on Cape Cod there were 442 salt works.
Mechanical evaporation began in about 1833, along with methods to purify the brine before evaporation allowing salt makers to produce a clean, white, desirable salt product. Further developments during the 1800's at Silver Springs, New York, produced the concept of crystallizing salt.
Between 1790 and 1860, salt was produced in Ohio, Michigan, Pennsylvania, Kentucky, Indiana, Illinois and Missouri by boiling brine in salt furnaces. Waste wood products from the lumber industry supplied low cost fuel to produce salt from salt springs at Saginaw and St. Clair, Michigan during the mid-1800's. Drillers found a rock salt deposit at St. Clair, Michigan in 1882, that provided a saturated brine to feed the evaporators. Solution mining of rock salt deposits spread rapidly throughout the salt producing states. When rock salt deposits were reached by drilling, conventional underground mining soon followed. Salt mining continues today throughout North America in Kansas, Louisiana, Ohio, New York, Texas, Ontario, New Brunswick (potash and salt), Quebec and Nova Scotia.
The Erie Canal, opened in 1825, was known as "the ditch that salt built" because salt, a bulky product presenting major transportation difficulties, originally was its principal cargo. Syracuse, NY, is to this day often called "Salt City."
In December, 1864, Union forces made a forced march and fought a 36-hour battle to capture Saltville, Virginia, the site of an important salt processing plant thought essential to sustaining the South's beleaguered armies.
The bottom line is, that white granular substance we take for granted is essential to life as we know and live it. We are fortunate that in the United States that it has never been subjected to discriminatory taxes, and that in North America it is plentiful and one of the most easily obtainable and least expensive of our necessities.
PRIMARY USES OF SALT
AS AN ESSENTIAL NUTRIENT — All animals, humans included, require both sodium and chloride for life and health. Since the body cannot manufacture either, they are "essential" nutrients. While developed countries dedicate most of their salt to chemical production, developing countries often use most of their salt for human and animal nutrition.
IN MAKING PAPER - The greatest single use for salt is in the production of chlorine and caustic soda used in paper making. The caustic soda is used to break down wood fibers and chlorine is used to bleach the pulp. It is also used to make sodium chlorate and metallic sodium by electrolysis, and sodium sulfate and hydrochloric acid by reacting with sulfuric acid. Sodium chlorate replaces chlorine as the primary chemical for bleaching pulp.
AS A DIETARY SUPPLEMENT — Livestock, poultry and other animals do not always receive adequate amounts of sodium and chloride from forages and other feeds. They need supplemental salt as part of a nutritionally balanced diet to remain healthy, disease free, and to achieve optimum growth and reproduction rates. Because animals have a natural, definitive appetite for salt (they will eat only a certain amount), it is used to ensure adequate intake of less palatable nutrients and as a means of limiting feed intake. Salt can be mixed with feed or fed free-choice, and is an excellent carrier for trace minerals. It is produced plain or as trace mineralized salt, in 50 lb blocks, smaller spools and as loose salt, commonly known as mixing salt.
AS A DE-ICER — Salt is the most effective, readily available, economical highway deicer in use today. It assures winter driving safety and continued mobility in snowbelt states, even under the most adverse snow and icing conditions. Rock salt and solar salt are used on U.S. highways. In Europe, because of its availability, evaporated salt is sometimes used. The lowest temperature at which sodium chloride will melt ice (the eutectic point) is -21.12° C (-6.02° F), at a concentration of 23.3% NaCl. Salt works best at temperatures near 0° C (32° F) because melting occurs quickly with a relatively small amount of salt. As the temperature falls, it takes more salt and more time to melt ice because a higher concentration of brine is required. Fortunately, most snowstorms occur when the temperature is near freezing, where salt is very effective. More than 40% of the dry salt produced in the United States is used for highway deicing.
AS A WATER SOFTENER — Water is considered hard when it contains calcium and magnesium (hardness ions). Hard water requires more soap and detergent for laundering, cleaning and bathing because suds do not form as well in hard water. The reaction between soap and hard water results in a greasy, curd-like deposit which makes fabrics feel harsh and leaves water spots on dishes and utensils. Mineral scale builds up in hot water appliances and industrial boilers, reducing energy efficiency and shortening appliance and equipment life. Water is conditioned or softened by removing the calcium and magnesium ions from hard water and replacing them with "soft" sodium ions. Water softeners use cation exchange resin to exchange sodium for calcium and magnesium. As supply water flows through the resin bed, the exchange takes place and the water becomes soft. Water softener cation exchange resins are regenerated with a 10% salt brine solution made by dissolving water softener salt.
IN INDUSTRIAL PROCESSES — Salt is used to fix and standardize dye batches in the textile industry; it is used in metal processing and secondary aluminum making, to remove impurities; rubber manufacturers use salt to separate rubber from latex; salt is used as a filler and grinding agent in pigment and dry-detergent processes; ceramics manufacturers use salt for vitrifying the surface of heated clays; soap makers separate soap from water and glycerol with salt; oil and gas drillers use salt in well drilling muds to inhibit fermentation, increase density and to stabilize drilling in rock salt formations; and hide processors and leather tanners use salt to cure, preserve and tan hides.
SOME SALT FACTS
|Crystal form||isometric, cubic|
|Density||2.165 (135 lb/cu. ft)|
|Melting point||800.8 °C (1,473.4 °F)|
|Boiling point||1,413 °C (2,575 °F)|
|Hardness||(Moh's Scale) - 2.5|
(Check out our Periodic Chart of the Elements for additional information.)