Question

Copper matte contains
A.$C{u_2}O,\,C{u_2}S$
B.$C{u_2}O,\,FeS$
C.$FeS,\,C{u_2}S$
D.$FeO,\,C{u_2}S$

Answer 1

To answer this question, you should recall the concept of extraction of copper. The commonest ore used in the extraction of copper is chalcopyrite $(CuFe{S_2})$ also known as Copper Pyrites and other such sulphides.

Complete step by step answer:
- Copper exists in the form of sulphide in the ore. After concentration of the ore, it is heated strongly with silicon dioxide, calcium carbonate and air or oxygen in a furnace or series of furnaces. This results in the copper (II) ions in the chalcopyrite being reduced to copper(I) sulphide.
- The iron impurities in the ore get converted into an iron (II) silicate slag which is removed. The other Sulphur impurities are converted into Sulphur dioxide gas. This method is used to produce sulphuric acid via the Contact Process.
- Copper matte is a mixture of copper sulfide $(C{u_2}S)$ and some iron sulfide $\left( {FeS} \right)$. Matte is a process in which copper is extracted before the final reduction. When a hot blast of air is blown through a molten matte placed in a silica lined converter, $FeS$ of the matte oxidizes to $FeO.$
This $FeO$ combines with $Si{O_2}$ (silica) to produce $FeSi{O_3}$;(slag).
- The reaction can be represented as: $2FeS{\text{ }} + {\text{ }}3{O_2}\; \Rightarrow 2FeO{\text{ }} + {\text{ }}2SO2FeO{\text{ }} + {\text{ }}Si{O_2}\; \Rightarrow FeSi{O_3}$.

Hence, the correct answer to this question is option C.

Note:
Another method of extraction of copper is electrolytic refining for extraction of copper from its ore. The purification in this method uses an electrolyte of copper (II) sulphate solution, impure copper anodes, and strips of high purity copper for the cathodes. At the cathode, copper (II) ions get deposited as solid copper due to reduction: $C{u^{2 + }} + 2{e^ - } \to Cu(s)$. At the anode, copper gets dissolved in the electrolyte as copper (II) ions $Cu(s) \to C{u^{2 + }} + 2{e^ - }$.