Extraction of zinc from zinc blende is achieved by
(a) electrolytic reduction
(b) roasting followed by reduction with carbon
(c) roasting followed by reduction with another metal
(d) roasting followed by self-reduction
Answers
(b) roasting followed by reduction with carbon
Answer: b) roasting followed by reduction with carbon is the correct answer.
Explanation:
Zinc has atomic number 30.
Its oxidation state is +2.
It is present in ores along with copper, silver and lead.
It is also present in Snake's venom and animal cells.
The important minerlas of Zinc are
Zinc blend
Calamine
Zincite
Willemite
The carbon reduction process consists of 4 stages
Concentration
Roasting
Reduction
Purification
In concentration zinc blend ore is freed from rocky materials.
This can be done by gravity seperation, flotation and electromagnetic seperation.
The concentrated zinc sulphide ore is roasted in reverberatory furnance in presence of excess air.
It takes place at 1000K.
Then the reduction process is fine by retort process or smelting.
Purification, the last step is done by electrolytic refining.
Hence, b) roasting followed by reduction with carbon is the correct answer.