Separation of mixtures

Separation of the components of the mixtures . The components of a mixture are separated taking into account several of their physical properties , such as the state of aggregation , the solubility in water or in another solvent and the boiling temperature .

For the separation of the components of the mixtures, one or more operations are carried out, both in the laboratory and in industry and the home.

Summary

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  • 1 Operations to separate the components of a mixture
    • 1 Decantation
    • 2 Filtration
      • 2.1 Use of decantation and filtration in water treatment
    • 3 Vaporization
    • 4 Distillation
  • 2 Source

Operations to separate the components of a mixture

  • Settling
  • Filtration
  • Vaporization
  • Distillation

Sometimes it is necessary to do only one of the mentioned operations to separate the substances that constitute a mixture. But in most cases you have to do two or more of these and even add a substance, usually a liquid. Other operations in the industry are more complex but are based on the same principle. If the components of a mixture and their properties are known, a prediction on how to separate them can be formulated and then tested in practice.

Settling

Settling

The decantation is carried out to separate the liquid component of one mixture from another (solid or liquid) practically insoluble in it and that after a relatively short time it is deposited in the bottom of the container.

The sand and water that form a mixture can be separated by decantation, as the sand is practically insoluble in water and settles at the bottom of the container after a short time.

The non-miscible (practically insoluble) liquids between each other, which constitute a mixture, as occurs with gasoline and water , are also separated by decantation. This mixture is poured into a separating funnel and allowed to stand until the separation between the two liquids is clearly observed (interface). Then the bottom one is decanted, while the other remains in the funnel. In this example, water forms the bottom layer.

Decantation can also be done by suction. In this case, the liquid is extracted with a dropper or with a suction pump , depending on the volume of liquid contained in the mixture.

In one of the phases of the industrial production of sugar or sucrose, the juice of the cane or guarapo is separated by decantation of the cachaça and solid impurities such as clays and sands.

Filtration

Filtration

Filtration is carried out to separate the liquid component of a mixture from another solid that is practically insoluble in the liquid and whose particles float on its surface or remain in suspension for a relatively long time.

The components of the mixtures of sawdust and water , as well as powdered chalk and water can be separated by filtration. Both solids are practically insoluble in this solvent. In addition, the sawdust floats on the surface of the water, while the powdered chalk, after remaining in suspension for some time, is deposited at the bottom of the container.

Filter paper is generally used in the laboratory to filter. During filtration, the liquid that passes through the filter is called filtrate and the solid that is retained in said filter is called waste.

In sugar mills , the guarapo that is extracted from sugar cane is separated from different suspended solids, among which is the bagasse, mainly by filtration. Also a large volume of juice contained in the cachaça is recovered by filtration. In addition, in the refining process of raw sugar, hot water is added to the cachaça formed in the refineries and then it is decanted or filtered to recover most of the sucrose that it may still contain (recovered).

In industrial processes, cloth cloth, glass wool , cotton , gravel or sand , wire cloth or canvas, among others, are used as filters .

Use of decantation and filtration in water treatment

The decantation and filtration of the water are carried out in the aqueducts , to make them drinkable. Thus, the water is pumped from the supply source to a place where the sedimentation of numerous solid impurities occurs, which will be separated by decantation of this solvent. But since the water still contains solid impurities on its surface or in suspension, they are removed by filtering them through a layer of sand in another section. Dichloro and other substances that destroy bacteria and pathogens are added to the filtrate . It is then stored in another area, ready for distribution to the population.

Decantation and filtration consist of transferring a liquid to a container, to separate it from one or more components (solid or liquid) of the mixture.

Vaporization

Vaporization

Vaporization is carried out to separate one or more solid components, generally dissolved, from the liquid component of a mixture , and is based on the different boiling temperatures of the substances that make up the mixture. In other words, vaporization involves the passage of a liquid into the gaseous state to separate it from one or more solid components of the mixture.

This operation is carried out, basically, to separate the components of a solution, as long as you want to collect the solute and it does not decompose into other substances at the temperature used. For example, if the seawater is vaporized, the solid substances dissolved in it are collected.

Vaporizing a liquid can be done at room temperature or with heating. In the latter case sometimes the mixture is heated to boiling to separate the solid from the liquid (vaporization by boiling).

If vaporization only occurs on the surface of the liquid at room temperature it is called evaporation, as it occurs in the sea , rivers, dams, puddles, etc.

porcelain capsule is frequently used in the laboratory for vaporization by heating. If vaporization is desired to occur at room temperature, then a crystallizer is generally used . Also vaporization is often used to dry wet solids.

Distillation

Simple distillation

Distillation is generally carried out to separate the liquid component or components from a mixture in which there is one or more dissolved substances (solid or liquid) and is based on the different boiling temperatures of the substances that make up the mixture .

Distillation is carried out, on many occasions, to separate the components of a solution, mainly when it is desired to collect the solvent or various liquids from the mixture. For example, if the water in the aqueduct is distilled , high purity water is collected, known as distilled water . This distillation is very simple, which is why it is called simple distillation.

In summary, the distillation consists of vaporizing, by heating, one or more liquid components of a mixture, to later condense those vapors and collect the liquids at different boiling temperatures. Therefore, during distillation two changes of state of aggregation occur: first the vaporization of the liquid and then the condensation of the vapor.

 

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