Decantation as when the sediments will settle down the impure liquid (that contains the dirt) with be poured out into an another container.Then the pure salt(sediments) will be taken out

Method to obtain pure salt from impure salt: Crystallization

Crystallization is the process used to obtain pure salt from impure salt. This method involves the separation of a solid substance from a solution by forming pure crystals.

Explanation:

Step 1: Dissolving impure salt in water
- The impure salt is first dissolved in water. This forms a salt solution where the impurities are mixed with the salt.

Step 2: Heating the solution
- The salt solution is then heated gently. As the water evaporates, the concentration of salt in the solution increases.

Step 3: Formation of crystals
- Once the solution becomes saturated, meaning it can no longer dissolve any more salt, it is left to cool slowly. As the solution cools, the salt molecules come together and form solid crystals.
- The impurities, being different substances, do not crystallize and remain in the solution.

Step 4: Separation of pure salt crystals
- The pure salt crystals are then separated from the remaining liquid using filtration or decantation.
- Filtration is used when the impurities are solid particles, while decantation is used when the impurities are liquid.

Step 5: Drying the salt crystals
- Finally, the obtained salt crystals are dried to remove any remaining water. This can be done by spreading the crystals on a flat surface and allowing them to air dry or by heating them gently.

Advantages of Crystallization:
- Crystallization is a simple and effective method for obtaining pure salt from impure salt.
- It does not require any complex equipment and can be easily performed.
- The process is based on the principle that different substances have different solubilities, allowing the separation of pure salt crystals from impurities.

Conclusion:
Crystallization is the method used to obtain pure salt from impure salt. This process involves dissolving the impure salt in water, heating the solution to increase the salt concentration, allowing the solution to cool and form crystals, separating the pure salt crystals from the remaining liquid, and finally drying the crystals. This method is efficient and commonly used in industries and laboratories for the production of pure salt.