Q. 225.0( 1 Vote )
Describe how the
(a) The leached gold complex is treated with Zinc.
2Au[(CN)2] - (aq) + Zn (s)2Au (s) + [Zn(CN)4]2 -
The gold is recovered by a displacement reaction.
(b) Zirconium Iodide is decomposed on a tungsten filament which is electrically heated at 1800 K. The pure metal is thus deposited on the filament.
ZrI4Zr + 2I2
This is a part of the van Arkel method for refining Zirconium.
(c ) In the extraction of copper, silica is added to the ore and heated. The iron oxide combines with the slag and is removed as iron silicate.
FeO + SiO2FeSiO3
a) NaCN is used as a depressant to separate two different sulfide ores ZnS and PBS in the froth floatation method. It selectively permits PBS to come with froth and prevents ZnS.
Froth Floatation is a method used for the concentration of ores. It is a method used for the separation of gangue materials from sulphide ores. In this method, a suspension of the ore is mixed with pine oil and frothed well. The ore particles get combined with the froth which is collected and dried.
b) Carbon monoxide is used in the Mond process to form a volatile complex of nickel - nickel tetracarbonyl from which nickel is extracted.
c) Coke is used as a reducing agent to reduce zinc oxide to zinc.
The metal is distilled off and cooled quickly.
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