SALT, BROMINE AND POTASSIUM CHLORIDE

Salt was the name originally given to the residue left by evaporation of sea water. Afterwards the name was employed to include all substances held in solution in sea water. Chemists ultimately extended the name to cover all combinations of an acid and a base. Sodium chloride (Nacl) now called common salt, is an example of the simplest type of chemical salt.

Sodium chloride, common salt, is essential to human life. Our bodies contain up to 450 grams of salt and we need to take in a few grams each week to stay healthy. The value of salt can be seen in the way Roman soldiers used to be paid in salt, leading to the phrase “worth his salt” and our word “salary”. The growth of industry has increased the demand for salt, both for direct use and as a raw material for producing other chemicals.

Throughout the world the main sources of salt are sea water, lake water and rock salt deposits. Salt is recovered from the sea and lakes by evaporation. Rock salt may be mined like coal, or recovered by drilling wells into the salt bed, forcing down pure water and pumping up the saturated brine which forms.

It is a deep red fuming liquid, member of the halogen elements as Group VII of the periodic table that is liquid at ordinary temperature and pressure. Rare element bromine is found in, nature dispersed throughout the earth crust only in compounds such as soluble and insoluble bromides. The chief commercial source of bromine is ocean water from which the element is extracted by means of chemical replacement (oxidation) by more active chlorine. Bromine has traditionally been manufactured as a byproduct from saline mother liquors (bitterns) left after the crystallization of the main salt products.

The properties of bromine are significantly different from those of fluorine and chlorine. Discovered in the early 19th century, in the form of its salts (bromides) in the bitterns remaining after evaporating sea water and extracting the sodium chloride, it was obtained latter from stassfurt, Germany, as a byproduct in the production of potassium salts and from other deposits and salt lakes.

Its main use was originally for bromides in medicine still a minor use. Bromine first because of industrial importance with the development of modern photographic process, in which the light sensitive material is an emulsion of minute particles of silver bromide (together with silver chloride or iodide or both) in gelatin.

For a time, the expanding world automobile industry. Threatened a scarcity of bromine, obtained from brines, which contained about 0.5% bromine. To meet the demand, it was necessary to turn to sea water which contains about 70 ppm bromine.

The chief sources of bromine are sea water, brines and betters and the natural deposits of potassium salts. In these, it is present in very small quantities in the combined state. Sea-water contains, 66 parts per million (0.0066%) of bromine and in 1933, the DOW Chemical Co., (U.S.A.) developed a process for its recovery. Large quantities of bromine are now being produced both from the sea and from the salt & lakes. The U.S.A. is now the world largest producer and used the entire output for the manufacture of ethylene bromine.

The other prominent bromine producing countries are Germany and France.

Bromine, a heavy, mobile, reddish-brown liquid with an interesting irritating odour, is the only non-metallic element that is a liquid at normal temperature. It is a diatomic molecule with the chemical formula Br2

The bromine available for extraction occurs as bromide in the ocean, in salt lakes and in brine or saline deposits left by evaporation of such waters by solar heat. Sea bitterns, the left over concentrated solution after the crystallizing out of salt from the sea water, are very rich in bromine and offer a good raw material for the manufacture of bromine. Bromine is extracted from seawater.

Potassium Chloride occurs naturally as Sylvite. However in general potassium compounds are recorded as valuable article of commerce.

Potassium chloride has a wide field of application viz. source of potassium salts, plant nutrient, salt substitute, and lab reagent, food additive, in slow release tablets and in other pharmaceutical preparations.

Potassium chloride finds its application as fire extinguishing agent. However potassium chloride as fire-extinguishing agent was originally developed as a protein – foam compatible agent with class B capabilities and is about as effective as potassium bicarbonate. It can ce somewhat corrosive and has a specialized use in air-crash fires where corrosion is not normally a problem.

Potassium chloride as in the case of Potassium bicarbonate and multipurpose agents is ground prior to processing As fre-extinguishing agent it is rated as a class B.C. agent by UL and ULC and at one time was listed as foam compatible.

Potassium chloride also is used as water correcting agent Water used in the brewing industry is often corrected to a uniform mineral salt content that corresponds to water known to give the most satisfactory final product. A wide variety of salts are used for this purpose including potassium chloride & others.

Also Potassium chloride finds its application in secondary batteries viz. lithium. Iron sulphide battery utilizers a molten salt eutectic of lithium chloride, potassium chloride at a temperature of you 400-500oC as electrolyte.

USES & APPLICATION OF POTASSIUM CHLORIDE

It is used as:-

1. Fertilizer
2. Source of Potassium Salts
3. Pharmaceutical Preparations
4. Photography
5. Spectroscopy
6. Plant Nutrient
7. Salt Substitute
8. Lab Reagent
9. Buffer Solutions
10. Food Additive
11. In Secondary Batteries
12. As Water-Correcting Agent
13. In Drilling Fluids