The compound(s) that is(are) removed as slag during the extraction of copper is:
(1) CaO
(2) FeO
(3) Al₂O₃
(4) ZnO
(5) NiO
Choose the correct answer from the options given below

We need to identify which compound(s) are removed as slag during copper extraction.

In the extraction of copper from copper pyrites ($$CuFeS_2$$), the ore is roasted and then smelted in a blast furnace or reverberatory furnace.

During smelting, silica ($$SiO_2$$) is added as a flux and the iron impurity in the form of $$FeO$$ reacts with silica via the reaction $$FeO + SiO_2 \rightarrow FeSiO_3 \text{ (ferrous silicate - slag)}$$ to form the slag.

When evaluating the options, CaO is not a typical impurity in copper pyrites extraction; FeO is removed as iron silicate slag ($$FeSiO_3$$); $$Al_2O_3$$ is not typically removed as slag in copper extraction; ZnO is not a primary slag component in copper extraction; and NiO is not typically removed as slag in copper extraction.

The main slag formed during copper extraction is ferrous silicate ($$FeSiO_3$$), formed from FeO.

Hence, the correct answer is Option B.