Question

How do we separate two sulphide ores by the froth flotation method?

Answer 1

Hint : We know that the froth floatation method is used for removing gangue from sulphide ore. Here the ore is mixed with water to form a suspension, then collectors are added, for example pine oil, fatty acid, and xanthates.

Complete Step By Step Answer:
As we know, the froth flotation method is widely used for the concentration of sulphide ore such as zinc sulfide, Copper pyrites and galena. It is based on the fact that the surface of sulphide Ore is preferentially wetted by oils while that of gangue is preferentially wetted by water. The froth flotation is a method which is used for the concentration of sulphide ores with the help of froth stabilizers and collectors. It is based on the principle of difference in wetting properties of ore and gangue particles with oil and water. The non-wettability of mineral particles means mineral particles become wet by oil while the gangue particles by water.
Froth stabilizers are added like cresol or aniline which stabilize the froth. After this a rotating paddle agitates the mixture and draws air in it so a froth is formed which takes the mineral particles. This method is also used to separate two sulphide Ores by using a depressant like sodium cyanide. For the separation of two sulphide ores, the proportion in which oil and water are taken should be adjusted. This can also be done by using depressants such as sodium cyanide. If an ore contains Zinc sulphide and lead sulphide then sodium cyanide is added during the process. Zinc sulphide forms a complex with sodium cyanide preventing it from coming into froth. Thus, Lead sulphide follows into the froth and that’s how it gets separated.

Note :
Remember that the froth flotation method can also be used for the purification of sulphide Chloride and potassium chloride and Minerals of clay; the crushed mineral is suspended in brine solution while fatty ammonium acids are present inside it.