Question

Which of the following is true for calcination of a metal ore?

• A. It makes the ore more porous
• B. The ore is heated to a temperature when fusion just begins.
• C. Hydrated salts lose their water of crystallization
• D. Impurities of S, As and Sb are removed in the form of their volatile oxide.

Answer 1

Answer: (A), (C)

The correct options are
A

It makes the ore more porous

C

Hydrated salts lose their water of crystallization

Calcination is a process in which concentrated ore is heated in a suitable furnace, generally much below its melting point in the limited supply of air or oxygen, which makes the ore porous and hydrated salts lose their water of Crystallization. During which impurities of Sulphur and arsenic are volatilized away as oxides and thus pores are formed in ores.

$S_8+8O_2\to 8S{O}_2$

$P_4+5O_2\to P_4{O}_{10}$

$4As+3O_2\to 2A{s}_2{O}_3$