Question

a) Name the method used for removing gangue from sulphide ores.
b) How is wrought iron different from steel?

Answer 1

Hint: a) To answer this question, we should know what is gangue? Gangue is the vein matter in which most of the valuable metals or many minerals are present. The process which is used to remove gangue is based on the chemical and physical properties of the gangue.
b) Wrought iron consists of iron Having very less amount of carbon and is purest form of iron having very less amount of impurities and no additives.. Steel is composed of carbon with other components too.

Step by step answer: (a) The method which is used for the removal of gangue from sulphide ore is froth flotation process. In this process, a mixture of oil (pine oil) and water is made to froth in the tank which separates the sulphide ores. The gangue particles and the ores separated because of the differences between the wetting properties of them.
Froth is produced by the compressed air through the pipe in the tank. The gangue particles wetted by the water and settles down at the bottom of the tank whereas sulphide ores wetted by the pine oil and these are more electronegative so it is transferred to other containers where or get washed and dried.
(b) The difference between wrought iron and steel is given below:

Wrought iron	Steel
It is alloy of iron and composed of almost pure iron with less quantity of carbon i.e., 0.02%	It contains less iron but more carbon content i.e., (0.15% to 0.25%)
Less tensile strength	High tensile strength due to more content of carbon.
Resistant to corrosion.	Non-resistant to corrosion.
It is more malleable and ductile so welders can easily recast into different designs.	It is less malleable and ductile

Note: Remember that in the froth flotation process, sulphide ore is more electronegative than gangue particles. Sulphide ore attracts to oil and gangue attracts towards water. Steel is a little stronger than wrought iron due to the presence of high carbon content in it.