JSS 2: Separation techniques

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            SEPARATION TECHNIQUES 

Separation techniques are physical methods used for the separation of the constituents of a mixture. A mixture contains two or more substances that are physically combined.

Examples of separation techniques are: 

1. Sieving

2. Filtration 

3. Sublimation 

4. Decantation 

5. Separating funnel 

6. Evaporation 

7. Centrifugation 

8. Distillation 

9. Fractional distillation 

10. Chromatography 

11. Crystallization 

12. Fractional crystallization 

13. Magnetic separation

  

SIEVING

This is used to separate solid particles of different sizes. Particles smaller than the size of the sieve (mesh) pass through leaving behind particles of larger sizes. It is used in gold and diamond mines and garri industries.

                            Sieving

FILTRATION 

This method is used to separate insoluble solids from liquids using a filter. For example, a mixture of chalk particles in water can be separated using a filtration technique.

Filtration is used in industries such as water purification plants and breweries.

                               Filtration

SUBLIMATION

Sublimation is the change of state from solid to gas directly on the application of heat. Examples of substances that sublime are iodine and ammonium chloride. Sublimation can be used to separate these substances. The pure crystal recovered is the sublimate.

                         Sublimation

DECANTATION

Decantation is a separation technique used to separate a mixture containing an insoluble solid from a liquid. This is done when the mixture is allowed to settle down with the upper clear liquid carefully poured or decanted into a clean container thereby leaving the lower solid in the container originally containing the mixture. This is a quick but inaccurate method of separating the components of a mixture.

                 

                          Decantation

SEPARATING FUNNEL

This is used to separate immiscible liquids. It depends on the densities of the two liquids. The less dense will be on top and the denser below. It is used to separate water and kerosene.

       Separating funnel method

EVAPORATION

Evaporation is used to recover soluble solute from its solvent. For example, salt can be separated from salt solution by evaporation.

 Evaporation of salt solution to dryness

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