Question

Which of the following methods is used to separate wolframite and stannic oxide present in cassiterite?
A. Hydraulic washing using Wilfley table
B. Froth floatation
C. Hydraulic classifier
D. Magnetic separation

Answer 1

Hint: An ore of tin is known as cassiterite which has impurity along with pure metal oxide. The separation is based on the principle that the impurity should have magnetic properties.

Complete answer:
-There are two metal molecules present in the ore of tin also known as cassiterite.
-The molecules are stannic oxide with a molecular formula of $\text{Sn}{{\text{O}}_{2}}$ it doesn't have magnetic properties.
-Another molecule is wolframite with a molecular formula of $\text{FeW}{{\text{O}}_{4}}$, it has magnetic properties.
-So, if we will use the magnetic separation method to separate them, then wolframite will attach to the magnet and stannic oxide will be separated.
-Other options like froth floatation method are used to separate the sulphur from impurities.
-The hydraulic classifier works on the principle of separating particles by the difference in the densities of the pure and impure molecules in the stream of water.
-A hydraulic classifier is used for oxide and carbonate ores.
-Hydraulic washing is based on the different specific gravity of the impurity and pure molecule in the ore.
-Hydraulic washing methods are generally used for lead and tin ores.

So, the correct answer is “Option D”.

Note: Magnetic separation can also be used in dairy, grain, oils and textiles. Ores like magnetite and ilmenite can also be separated using this technique because they are the ores of iron and we all know that they have magnetic properties.