In nature it is not possible to find all substances in their pure state, however, even when they are mixed they do not lose their chemical characteristics, so it is possible to separate them using the methods following:
filtration: this method consists of passing the mixture through a porous surface, in this case a filter, which retains the solid part and allows the liquid part to pass through. There are several types of filters: cotton, paper, porcelain, etc. To be considered drinking water, it has to pass through the filter plugs, which retain disease-causing microorganisms. Another example is when we use paper filters to prepare coffee.
Decantation: In this process, a mixed liquid is separated from another. The heterogeneous mixtures of liquids, if left for a while, have their solid part deposited at the bottom of the container. This can be seen in a mixture of water with sand or clay, for example. You can do this experience yourself, without difficulty. After the solid part has settled to the bottom of the container, we can pour the liquid part into another container, separating them.
Magnetic Separation: It is a method used to separate ferromagnetic metallic materials from others by the magnet's attraction force. A mixture of iron filings (dust) with another substance, sulfur dust, for example, can be separated using a magnet. Bringing the magnet closer to the mixture, the iron filings attach to it, separating from the sulfur.
Ventilation: Do you know the rice processing machine? It separates the husk from the grain as if it were blowing. The rice husk is less dense than the rest of the grain and is carried along with the air current. Ventilation is the method of separating a solid substance, of different density from the immersed medium, through a current of air.
Thamisation: When preparing the cake, the grocers usually sift the flour and yeast. In this way, the good flour is separated from the lumpy one. The finer part (the good flour) passes through the meshes of the sieve and the lumps are retained. In laboratories, very fine sieves called sieves are used, so the process of separating mixtures by means of sieves is called sieving.
By Líria Alves
Graduated in Chemistry
Source: Brazil School - https://brasilescola.uol.com.br/quimica/fracionamento-misturas-heterogeneas.htm
