Question

Pyrite ores are concentrated by which of the following methods?
(A) Calcination
(B) Roasting
(C) Froth Floatation Method
(D) Distillation​

Answer 1

Hint: Think about all the processes one by one: calcination , roasting , froth floatation method and distillation. Think about the types of which can be concentrated calcination , roasting, froth floatation method and distillation.

Complete Step by Step Solution:
Let’s describe the froth floatation method .An aqueous sludge of the ground ore is treated with the frothing agent. sodium ethyl xanthate is an example used as a collector in the flotation of galena (example: lead sulphide) to separate it from sphalerite (e.g., zinc sulphide).

The ore particles attach with the polar part of xanthate and a hydrophobic layer from with the non-polar hydrocarbon part. air bubbles bring the particle to the water surface. hydrophobic action efficiency increases, but the increase in length of hydrocarbon chain in xanthates as the selectivity to ore type decreases.

It is highly selective to copper, nickel, lead, gold and zinc ores because the chain is the shortest in sodium ethyl xanthate. Normally Aqueous solutions (10%) with pH = 7–11 are used in the process. This pulp of hydrophobic particles and hydrophilic particles is introduced to tanks known as flotation cells that are aerated to produce bubbles. The hydrophobic particles attach to the air bubbles and by forming froth rise to the surface.

The froth is removed from the cell by producing a concentrate of the target mineral. It is the whole froth floatation process. So it's clear that for the froth flotation process ore is perfect for concentrating the pyrite ores.
Hence option C is the correct option.

Note: In general, the calcination process is used to concentrate carbonate ore, while roasting is utilised to concentrate sulphide ore. Distillation is used to concentrate metals having low boiling points, such mercury and zinc. The method of froth flotation is often utilised for ore that has greater density impurities. Sulphide ores are mostly concentrated using it.