Done by: Li Shida (1O2)

1. How is Sodium Chloride(Salt) obtained commercially? Done by: Li Shida (1O2)

2. Definitions • Brine solution: H2O + NaCl (water + salt) • Commercially (In This Case): Methods that are used to obtain NaCl is suitable for commercial uses.

3. 3 Main Methods • Solar Evaporation • Rock Salt mining • Vacuum Evaporation

4. Solar evaporation • Oldest Method • First observed in sea water caught in holes and evaporate to form salt as a natural process • Was manually done by our ancestors to obtain salt • Commercialized now days • Evaporation, Filtration and Crystallization used

5. Step 1 Step 1: Diverge large amounts of sea water into salt ponds. The ponds must be large in total area for commercial production.

6. Step 2 Step 2: Wait for natural evaporation • This process might take 2 years • Concentration of water causes crystallization • Chemicals such as calcium carbonate will crystallize first and will be removed • Sunshine and wind are key factors. The more of these, the faster the evaporation will take place.

7. Step 3 Step 3: Removal of brine solution into crystallizing ponds • The saturated salt solution will be filtrated and pumped into crystallizing ponds • Other impurities that are not dissolved will be drained away

8. Step 4 Step 4 : Crystallization & final cleaning • All water will evaporate in the crystallization ponds, forming solid NaCl of purity more than 99.7% • The NaCl will then be washed with brine solution. Since no salt can dissolve more in the brine solution, there will be no loss • 99.8% purity of NaCl is finally obtained

9. Separation Methods used • Filtration: Impurities that can affect the quality of NaCl production is removed • Evaporation: Saves energy as compared to manual heating. Concentrates water • Crystallization: To obtain almost pure dry NaCl, the final product

11. Method 2: Rock Salt Mining • Second oldest method • Mines rock salt underground 2 types of rock salt deposit: Vein form and dome form Vein form: salt deposit spreads over a large area like veins Dome form: Salt chunked together in large amounts

12. Step 1 Step 1: Locating & Blasting • After a salt deposit is located, explosives will be used to make them fall to the ground. Older methods such as mining was also used.

13. Step 2 Step 2: Crushed into manageable chunks & hauled to the surface • Transportation of rock salt requires it to be smaller in size

14. Step 3 Step 3: Screening • The rock salt is screened to make sure that its quality is of standard. • Some minerals must be removed because it might be harmful. • A brine solution might also be used to treat it. The solution might also be filtrated to leave the rock salt as the residue. • 99. 8% purity of NaCl is obtained

15. Methods used & Process • Filtration: Filters the unwanted minerals away. Important for quality control of the salt.

16. Vacuum Evaporation • Dissolving rock salt or solar salt in water to create a brine solution, then boiling off the water to leave behind pure salt. • Newest and most high-tech method • Lowers atmospheric pressure to lower boiling point • Can increase purity to 99.99%

17. Step 1 Step 1: Dissolving • Rock salt or solar salt is dissolved to obtain a brine solution • Normally done in large amounts

18. Step 2 Step 2: Boiling • The brine solution will be pumped into a vacuum • The boiling point lowers since there is less atmospheric pressure in a vacuum • Water is boiled away to obtain 99.99% purity of NaCl

19. Interesting facts about vacuum evaporation • Purifies salt to meet high standards of purity • The vacuum “boiling pots” can be stacked together, with pots on top having a lower atmospheric pressure than pots below. The water vapor from the lower ones can cause the upper one to boil, saving energy and money

20. Methods used & process • Evaporation: Separation of NaCl and H2O was very important and evaporation does the job well

21. Bibliography • http://www.scribd.com/doc/17490071/How-is-Salt-Produced • http://www.saltinstitute.org/Production-industry/Production-technologies/Solar-salt-sea-salt • http://www.mortonsalt.com/salt-facts/salt-production-and-processing • http://www.bigsiteofamazingfacts.com/how-is-salt-made • http://www.madehow.com/Volume-2/Salt.html • http://www.cargill.com/salt/about/howsaltismade/index.jsp

22. Thank you