Question

For which of the following ores froth floatation method is used for concentration?
A. Haematite
B. Zinc blende
C. Magnetite
D. Carnallite

Answer 1

Hint: Recollect the concepts of metallurgy. To answer the correct compound we should know about the froth floatation process. We should know that froth floatation is separation of hydrophobic materials from hydrophilic. Find out the minerals which are separated using the froth floatation process and then attempt the answer.

Complete step by step answer:
So, first of all we'll know about the froth floatation process. Froth floatation is one of the most popular processes for mineral processing. In this process we separate minerals commercially. These minerals are separated from their impurities.
If we want to separate minerals from impurities we will do the separation by creating froth on which minerals separate out. We should know that this method of froth floatation is a method of mineral processing in which different minerals are separated according to our need. Such ores containing multiple metals such as lead, copper and zinc can be selectively extracted by using froth floatation.
Now we will know about the simple principle of working of froth floatation. The process of froth floatation starts with the increase of the surface area of the ore. The ores are crushed into a fine powder which is then mixed with water. The mixture obtained is called Slurry. We add a surfactant chemical to the slurry to enhance the hydrophobic nature of the mineral.
Then we force the air into it to create bubbles. The required mineral is repelled by water and thus, gets attached to the air bubbles. As these air bubbles rise up to the surface with mineral particles sticking to it, these are called froth or scum. This Froth is separated and further taken for the next process of refining and extraction.
We generally use this process for metals of low reactivity generally sulphur compounds. We should note that sulphide ores are easily wetted by the oils which will make them float on water. First of all, these minerals are first converted into a fine powder and then mixed with water. After that we add oil to this slurry. By injecting high pressure air bubbles are created. After this we notice that sulphide ore comes on the top with the froth and oil. The remaining gangue particles which did not dissolve in oil settle down. The foam is removed and we remove it for further processing. Hence we now separated the minerals by the froth -flotation process.
Froth floatation process is diagrammatically represented as follows:

So, if we now look at the options only zinc blende has sulphur present so it is our correct answer.
So, the correct answer is “Option B”.

Note: In froth floatation process, we use a collector. Collectors are such types of organic compounds that when added selectively attach to the surface of the minerals and add water repelling nature to the particles. This makes it very important, because we are able to extract useful minerals. Examples of collectors are fuel oil and kerosene oil.