Purifying salt from rock salt involves a simple process of dissolving, filtering, and evaporating. This method effectively separates the salt from insoluble impurities present in the rock salt.
The Purification Process: A Step-by-Step Guide
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Crushing: First, crush the rock salt into smaller pieces. This increases the surface area, allowing for faster and more complete dissolution in the next step. [Reference 1, Reference 7]
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Dissolution: Add water to the crushed rock salt. Stir the mixture thoroughly to dissolve the salt. The salt (sodium chloride) will dissolve in the water, leaving behind insoluble impurities like sand, clay, and other minerals. [Reference 2, Reference 7, Reference 9]
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Filtration: Filter the mixture using a filter paper or a cloth to remove the undissolved solids. This step separates the insoluble impurities from the saltwater solution. The filtered liquid, called the filtrate, contains dissolved salt and water. [Reference 3, Reference 7, Reference 9]
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Evaporation: Carefully evaporate the water from the filtrate. This can be done by boiling the solution or allowing it to evaporate slowly. As the water evaporates, pure salt crystals will be left behind. [Reference 5, Reference 7, Reference 9]
Tips for Optimal Purification
- Use clean water: Starting with clean water ensures that you don't introduce additional impurities.
- Fine filter: Using a fine filter during filtration will remove even the smallest solid particles.
- Gentle evaporation: Slow evaporation produces larger, more aesthetically pleasing salt crystals. Boiling can potentially splatter the solution.
Understanding the Process: Chemistry in Action
This purification method leverages the difference in solubility between salt and the impurities found in rock salt. Salt readily dissolves in water, while many impurities do not. Filtration separates the dissolved salt from insoluble matter, and evaporation separates the salt from the water.
