Question

How to concentrate an ore of tin containing $\left( {FeCr{O_4}} \right)$ ?

Answer 1

Hint : To answer this question we should have a proper knowledge of extracting process and various ores. Also we need to have the knowledge of magnetic properties of compounds that is the compound is ferromagnetic, anti-ferromagnetic, paramagnetic, diamagnetic, etc. We will discuss the properties of tin and the compound given in question below in brief.

Complete Step By Step Answer:
As we know that $FeCr{O_4}$ is ferromagnetic in nature so an ore of tin can be concentrated by magnetic separation. Magnetic separation is based on the differences in magnetic properties of the ore components. For example, we know that iron ore gets attracted towards magnets, therefore, the impurities which are non-magnetic in nature can be separated from them using magnetic separation. In this process finely ground ore is put onto the conveyor belt and below there is a magnet present. So when the ores move forward, the magnetic ore present in it gets attracted by the magnet and the non-magnetic particles or impurities get dispatched separately. It is the most important physical separation technique.

Note :
The name of the compound $FeCr{O_4}$ is iron $\left( {II} \right)$ chromate. There are many other compounds of iron chromate such as $F{e_2}{\left( {Cr{O_4}} \right)_3}$ it is called iron $\left( {III} \right)$ chromate and this can be formed by the reaction of potassium chromate and iron $\left( {III} \right)$ nitrate. Another method to form it is by the oxidation of iron by air and chromium oxides in a basic environment. It was discovered by Samuel Hibbert-Ware in $1817$ .