Question

An ore gives carbon dioxide on treatment with dilute acid. Identify the ore and name the process that should be used to concentrate this.

Answer 1

1. Identification of ore

The ore that gives Carbon dioxide $\left({\mathrm{CO}}_2\right)$ gas on reaction with dilute Hydrochloric acid $\left(\mathrm{HCl}\right)$ is a carbonate ore.

$\mathrm{Metal}\mathrm{carbonate}+\mathrm{dil}.\mathrm{HCl}\to \mathrm{Metal}\mathrm{oxide}+{\mathrm{CO}}_2$

2. Process used to concentrate the ore

Carbonate ores can be concentrated by using the process of calcination followed by reduction.

1. Calcination is the process of heating the concentrated ore in the absence of air. This method is usually used for the conversion of carbonate ores and hydrated oxide ores into their oxides.

$\mathrm{Metal}\mathrm{carbonate}\stackrel{\mathrm{Calcination}}{\to }\mathrm{Metal}\mathrm{oxide}+\mathrm{Carbon}\mathrm{dioxide}$

2. In the reduction process, the metal oxide is further reacted with carbon which forms a free metal with the release of Carbon monoxide (CO) gas.

$\mathrm{Metal}\mathrm{oxide}+\mathrm{Carbon}\left(\mathrm{coke}\right)\stackrel{\mathrm{Reduction}}{\to }\mathrm{Metal}+\mathrm{CO}$

Therefore, the ore is Carbonate and the process used to concentrate the metal is calcination followed by reduction.