collection, flotation and levigating are separation methods of heterogeneous mixtures. Let's look at each case in particular:
collection
This is perhaps the oldest way to separate heterogeneous mixtures. The method can be used for simple tasks performed in our own homes, such as separating impurities from cereals and vegetables. This is an old task, from grandma's time, but it perfectly portrays how we can separate heterogeneous mixtures through grooming.
Before cooking rice, beans, soybeans, lentils, peas, etc., the housewife used to select the grains. The selection was made by separating immature grains (which did not develop), pebbles and other residues from the manual harvesting process. These materials (impurities) were removed, or rather, separated from the food through the hands of the cook.
Currently, any of these impurities that may be mixed with the grains are removed with the help of specialized machines. Food distributors ensure that cereals and vegetables arrive clean at our tables, and there is no longer the need to select such foods.
Now you know! The process of manually separating the different components (or phases) that make up a mixture is called grooming. The term comes from the act of “picking up” the ingredients.
Flotation
If you were to separate, for example, a mixture of sand and washing powder, which method would you use?
Flotation is a great alternative to fractionate these components.
In the first instance, you submit the ingredients of the mixture to a dissolution, place them in a bowl and add water. The less dense part of the mixture (the washing powder) dissolves in the water and floats, while the denser part (the sand) is submerged in the bottom of the container.
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THE flotation it can be used in mining to separate ores from their impurities. The rock to be mined is subjected to crushing and then oil is added. The ore particles, taken from the rock, attach themselves to the oil. If we add water to the set, the particles fixed in the oil go to the surface, and the impurities stay at the bottom of the container.
Levitation
The mixture formed by solid substances of many different densities can be separated considering the ownership of each phase. If we submit the mixture to a stream of water, we will have the components separated by density, a method called levigating.
A great example of this method is the one used for gold extraction in the mines. Typically, gold is found near a patch of earth or sand. To separate these substances, the mixture is crushed in a proper container and a stream of water is applied to it. The less dense part (the sand or the earth) is carried by the water, and the denser (the gold) is deposited in the fund. In this way, we separate the denser elements from the less dense ones.
By Líria Alves
Graduated in Chemistry
Would you like to reference this text in a school or academic work? Look:
SOUZA, Líria Alves de. "Scavenging, Flotation and Levitation"; Brazil School. Available in: https://brasilescola.uol.com.br/quimica/catacao-flotacao-levigacao.htm. Accessed on June 27, 2021.
