Question

is FeO magnetic in nature if so then why is silicone added to seperate iron oxide from an sulphide ore of copper rather than using the magnetic seperation. is adding silicone also a way of concentration?

Answer 1

Dear student,

FeO is paramagnetic in nature due to presence of unpaired e^- and is attracted towards magnetic field.
FeO is a rare ore which can be concentrated (or separated from gangue) using magnetic separation method if the gangue is not attracted towards magnetic field.

Silica is not a way for concentrating, it separates FeO in the form of slag from the ore in blast furnace. In actual process, while heating the ore of copper in a reverberatory furnace, the following reaction takes place:
2 CuFeS₂+ 3 O₂→ 2 FeO + 2 CuS + 2 SO₂
2CuS + 3O₂ → 2CuO + 2SO₂
CuO + C → Cu + CO
In the furnace, silica( SiO₂) is mixed with the ore and hence iron oxide ‘slags of’ as iron silicate and copper is produced in the form of copper matte which contains CuS. FeO and CuS can mix, but when sufficient silica is added, a separate slag layer is formed.
FeO + SiO₂ → FeSiO₃ (Slag)
Slag is less dense than matte, so it forms a layer that floats on top of the matte.

Regards

​