Froth Floatation Process - Practice Questions & MCQ

In the Froth Floatation process, you will come across different terminologies. Let's discuss them.

1. Frothers - Frother is an agent that is active in froth flotation through its ability to change the surface tension of a liquid generate a stable froth that rises to the top of the tank. Example -  pine oil, Eucalyptus oil, etc.
2. Froth stabilizers - Froth stabilizers are those substances that help stabilise the froth formed during the froth floatation process. Example - cresols, aniline, etc.
3. Collectors - A collector is a chemical that selectively binds to the surface of target minerals and imparts hydrophobicity to those mineral particles, a necessary condition for air bubble attachment. Example - pine oils, fatty acids, xanthates, etc.
4. Depressants - These reagents depress the flotation property and help in the separation of different sulphide ores present in a mixture. We can say ‘Depressants’ are used for adjusting the proportion of oil to water to separate two sulphide ores. Example: ore containing ZnS and PbS, the depressant used is NaCN.

This method is used for removing gangue from sulphide ores. In this process, a suspension of the powdered ore is made with water. Collectors and froth stabilisers are added to it. Collectors (e.g., pine oils, fatty acids, xanthates, etc.) enhance non-wettability of the mineral particles and froth stabilisers (e.g., cresols, aniline) stabilise the froth. The mineral particles become wet by oils while the gangue particles by water. A rotating paddle agitates the mixture and draws air in it. As a result, froth is formed which carries the mineral particles. The froth is light and is skimmed off. It is then dried for recovery of the ore particles. Sometimes, it is possible to separate two sulphide ores by adjusting the proportion of oil to water or by using 'depressants.' For example, in the case of an ore containing ZnS and Pbs, the depressant used is NaCN. It selectively prevents ZnS from coming to the froth but allows Pbs to come with the froth.