Techniques for Separating Mixtures

Separating Mixtures

Open Ended

Based on your knowledge of the properties of materials, how would you separate salt dissolved in a beaker of water?

Depending on the properties of the different substances, mixtures can be separated using different techniques.
Filtration, decantation, evaporation, magnetic spearation, and sieving are some of these techniques.

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Separating Mixtures

Filtration is used to separate solids from liquids or gas using a filter medium.
The medium may be a surface filter or a depth filter.
The solid particles are called residue. The filtered liquid is called the filtrate.

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Filtration

Decantation is used to separate insoluble solids from a liquid, or two liquids with different densities.
Sedimentation occurs when solid particles sink to the bottom of the container. This makes it easier to pour out the liquid only.
For two liquids, the denser liquid is allowed to settle at the bottom of a funnel. Then, it is allowed to flow out from an opening.

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Decantation

In evaporation, the liquid substances are boiled until the substance with the lower boiling point turns into gas.

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Evaporation

Magnetic Separation is used to separate magnetic from nonmagnetic substances.
It is used in food production, mining, recycling, mineral processing and many more.

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Magnetic Separation

Sieving is a method of using a sieve to separate particles of different sizes.
Sieves have a plastic or wire mesh in a frame. Fine particles are separated from coarser particles by using a sieve.

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Sieving