Describe how the following steps can be carried out?
(a) Recovery of Gold from leached gold metal complex.
(b) Conversion of Zirconium iodide to pure Zirconium.
(c) Formation of slag in the extraction of copper.
(Write the chemical equations also for the reactions involved)

Explanation

(a) Leached gold complex is treated with Zinc and gold is recovered by displacement method
`2Au[(CN)_(2)]^(-)(aq) + Zn(s) to 2Au(s) + [Zn(CN)_(4)]^(2-)(aq)`
(b) Zirconium iodide is decomposed on a tungsten filament, electrically heated to 2075 K. Pure Zr metal is deposited on the filament.
`ZrI_(4) to Zr + I_(2)`
(c) Silica is added to the ore and heated. It helps to slag off iron oxide as iron silicate
`FeO + SiO_(2) to FeSiO_(3) ("slag")`