JEE Main · 2023 · 30 Jan 2023 · Shift 1 · General Principles and Processes of Isolation of Metals

In the extraction of copper, its sulphide ore is heated in a reverberatory furnace after mixing with silica to :

(A)separate CuO as $CuSiO X_{3}$
(B)remove calcium as $CaSiO X_{3}$
(C)decrease the temperature needed for roasting of $Cu X_{2} S$
(D)remove FeO as $FeSiO X_{3}$ ✓ Correct

Answer: (D)

Solution

Copper sulphide ores are always contaminated with iron, which appears as iron(II) oxide once the ore is partly roasted. Silica is added as an acidic flux in the reverberatory furnace, where it combines with this basic oxide by

FeO + Si O_{2} \to FeSi O_{3}

. The iron silicate forms a light, fusible slag that floats on the molten matte and is run off, freeing the matte of iron. The silica is mixed with the ore so as to remove iron(II) oxide as iron silicate slag.

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JEE Main · 2023 · 30 Jan 2023 · Shift 1 · General Principles and Processes of Isolation of Metals

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