All About Salt: Properties, Mining, Production, and Uses

1. COMMODITY SALT What are salts?

2. WHAT ARE SALTS? • Formal name for NaCl is Halite • Chemically defined as reaction between Na, Cl and H2O to form NaCl or compound of metal and non metal • Greek word ‘hals’ means saltSalt – crystalline compound NaCl. • Salt-halite – colourless to yellow, but may be light blue, light blue and pink • Pure NaCl contains by weight 39.34% Na and 60.66% Cl • NaCl sometimes known as common salt or table salt • Salt was used as currency to soldiers in the Roman society

3. PROPERTIES OF SALT • Colourless to white but sometimes red, blue and purple • Exhibit isometric • Refractive index of 1.554 • Hardness of 2 • Cell contents is Na4Cl4 • Perfect cleavage • Specific gravity of 2.168 • Melting point of 804 degrees Celsius(1,479F) • Boiling point of 1,413 degrees Celsius(2,575F)

4. MINERAL PHOTOS - SALT Mii Photos Halite (Sodium chloride--Salt)

5. GEOLOGIC DESCRIPTION - SALT • Deposits are either in solution or in solid state • Bedded Salt Deposit: Deposit is associated with sedimentary rocks such as limestone, shale, dolomite and anhydrite. • Salt Domes: formed as a results of deposition of restricted marine basins, over period of time salt is then covered with sediment and becomes buried. • Lakes: Formed as a results of natural accumulations of water in topographic depression. • Groundwater: Formed either by connate or meteoric water. Examples are chloride-sulphate, chloride-carbonate, sulphate-carbonate and acids. • Solid Salt: They are found in playa lake deposits, bedded salt deposit and salt domes.

6. MINING - SALT • Rock salt is mined using room-and-pillar method of UG mining. - U.S and Canadian rock salt mine used this method. • Salt can be produced by controlled evaporation of seawater or brines in salt lakes. -This process is used at Great Salt lake in Utah- U.S • Vacuum pan process, this uses mechanical evaporation technology - Salt is obtained by dehydrating brines using heat or in combination with a vacuum. • Salt is produced in most countries on earth.

7. PRODUCTION - SALT • Oceans – 42% of salt is dissolved in oceans • U.S - produces about 1/5 of the world’s salt • U.S - also import about 1/5 of her salt from other countries. • In U.S. 40% of salt is used in chemical industry and another 40% as a de-icer on roads during winter • U.S. table salt account for only 1%

8. PRODUCTION - SALT Cont.

9. PRODUCTION - SALT Cont. Source:

10. USES - SALT There are numerous uses of salts in the world, the following includes some of the uses. • Food seasoning and food preservation • Canning process- use as flavour enhancer and preservative • Baking- use in baking industry to control rate of fermentation in bread dough • Preparation of sodium hydroxide, soda ash, caustic soda, chlorine, hydrochloric acids.

11. USES - SALT cont. • In oil and gas exploration- drilling fluids • Textiles and Dyeing- as brine to separate organic contaminants • Use in the manufacture of neoprene rubber, white rubber and other plastics. • High way de-icing- use to melt snow and ice on roadways

12. FORMULA- Other uses

13. SUBSTITUTES - SALT • No economic substitutes for salt • Calcium chloride and calcium magnesium acetate, hydrochloric acid and potassium chloride can be substituted for salt but at higher cost.

14. REFERENCES - SALT • 1. Barker, J.M., Kogel, J.E., Trivedi, N.C., and Krukowski, S.T., 2006, Industrial minerals and rocks, 7th Edition. • 2. www.saltinstitute.org/images/map.pdf • 3. USGS, Minerals Commodity Summaries, January 2011 • 4. USGS, Minerals Yearbook - 2009