. An ore on heating in air produces sulphur dioxide. What type of ore is this
How can it be concentrated? How can the metal be obtained from the concentrated ore?
Ans: An ore which on heating in air produces sulphur dioxide is a sulphide ore.
It is concentrated by froth-floatation process.
The metal is obtained from the concentrated ore in the following two steps:
i. Roasting: It is heating the ore strongly in the presence of air. The metal sulphide is converted into metal oxide along with evolution of sulphur dioxide gas. For example, Cinnabar (HgS) is an ore of mercury. When it is heated in air, it is first converted into mercuric oxide (HgO)
ii. Reduction: Mercuric oxide is then reduced to mercury on further heating.