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DESCRIPTIONHow is Sodium Chloride(Salt) obtained commercially?. Done by: Li Shida (1O2). Definitions. Brine solution: H2O + NaCl (water + salt) Commercially (In This Case): Methods that are used to obtain NaCl is suitable for commercial uses. 3 Main Methods. Solar Evaporation Rock Salt mining - PowerPoint PPT Presentation
Done by: Li Shida (1O2)
How is Sodium Chloride(Salt) obtained commercially?
• Brine solution: H2O + NaCl (water + salt)• Commercially (In This Case): Methods that are
used to obtain NaCl is suitable for commercial uses.
3 Main Methods
• Solar Evaporation• Rock Salt mining• Vacuum 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
Step 1: Diverge large amounts of sea water into salt ponds.The ponds must be large in total area for commercial production.
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.
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
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
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
Diverge Sea water into
evaporation ponds (~3.5% concentration)
Removal of impurities
Crystallization & Final
Method 2: Rock Salt Mining
• Second oldest method• Mines rock salt underground2 types of rock salt deposit: Vein form and dome formVein form: salt deposit spreads over a large area like veinsDome form: Salt chunked together in large amounts
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.
Step 2: Crushed into manageable chunks & hauled to the surface• Transportation of rock salt requires it to be
smaller in size
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
Methods used & Process
• Filtration: Filters the unwanted minerals away. Important for quality control of the salt.
• 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%
Step 1: Dissolving• Rock salt or solar salt is dissolved to obtain a
brine solution• Normally done in large amounts
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
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
Methods used & process
• Evaporation: Separation of NaCl and H2O was very important and evaporation does the job well