Question

The ore containing the impurity of\[\;F{e_2}Cr{O_4}\] is concentrated by?
A) Magnetic separation
B) Gravity separation
C) Froth floatation process
D) Electrostatic method

Answer 1

Hint: The ore \[\;F{e_2}Cr{O_4}\] is ferromagnetic substance. It’s an ore of tin and as Iron is magnetic in nature. It is attracted by a magnet. The impurity is not attracted by a magnetic. In other words, impurity is nonmagnetic in nature. Thus, using the magnet, you can separate \[\;F{e_2}Cr{O_4}\] ore from the impurity.

Complete answer:
The concentration of ore means removal of the gangue or waste material from the ore. There are various methods which depend upon the properties of ore.An ore of tin-containing \[FeCr{O_4}\] is concentrated by magnetic separation as \[\;F{e_2}Cr{O_4}\] is ferromagnetic in nature.

Magnetic separation based on differences in magnetic properties of the ore components. If either the ore or the gangue is attracted towards the magnetic field, then the separation is carried out by this method.

For example, iron ores are attracted towards the magnet; hence, non–magnetic impurities can be separated from them using magnetic separation.

Here, \[\;F{e_2}Cr{O_4}\] being an iron ore can be separated by magnetic separation. Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic example cinnabar \[\left( {HgS} \right)\]. Electrostatic method is used most often in the process of sorting mineral ore.

Hence the correct answer is option ‘A’.

Note:The method of concentration of ore completely depends upon the ore containing metal. Thus, you cannot use a magnetic separation method when both ore and the gangue are non-magnetic. Similarly, you cannot use the froth floatation process when you separate hydrophobic ore from hydrophobic gangue.