Advertisements
Advertisements
Question
Write chemical reactions taking place in the extraction of zinc from zinc blende.
Solution
The different steps involved in the extraction of zinc from zinc blende (ZnS) are given below:
(i) Concentration of ore
First, the gangue from zinc blende is removed by the froth floatation method.
(ii) Conversion to oxide (Roasting)
Sulphide ore is converted into oxide by the process of roasting. In this process, ZnS is heated in a regular supply of air in a furnace at a temperature, which is below the melting point of Zn.
`2 ZnS + 3O_2 -> 2ZnO + 2SO_2`
(iii) Extraction of zinc from zinc oxide (Reduction)
Zinc is extracted from zinc oxide by the process of reduction. The reduction of zinc oxide is carried out by mixing it with powdered coke and then, heating it at 673 K.
iv) Electrolytic Refining
Zinc can be refined by the process of electrolytic refining. In this process, impure zinc is made the anode while a pure copper strip is made the cathode. The electrolyte used is an acidified solution of zinc sulphate (ZnSO4). Electrolysis results in the transfer of zinc in pure from the anode to the cathode.
Anode : `Zn -> Zn^(2+) + 2e^(-)`
Cathode: `Zn^(2+) + 2e^(-) -> Zn`
APPEARS IN
RELATED QUESTIONS
How is 'cast iron' different from 'pig iron'?
Write down the reactions taking place in different zones in the blast furnace during the extraction of iron.
The choice of a reducing agent in a particular case depends on thermodynamic factor. How far do you agree with this statement? Support your opinion with two examples.
How will you convert the following:
Zinc blende to Zinc metal
In the metallurgy of aluminium ______.
Choose the correct option of temperature at which carbon reduces \[\ce{FeO}\] to iron and produces \[\ce{CO}\].
For the reduction of \[\ce{FeO}\] at the temperature corresponding to point D, which of the following statements is correct?
Wrought iron is the purest form of iron. Write a reaction used for the preparation of wrought iron from cast iron. How can the impurities of sulphur, silicon and phosphorus be removed from cast iron?
The purest form of iron is prepared by oxidising impurities from cast iron in a reverberatory furnace. Which iron ore is used to line the furnace? Explain by giving reaction.
The mixture of compounds A and B is passed through a column of \[\ce{Al2O3}\] by using alcohol as eluant. Compound A is eluted in preference to compound B. Which of the compounds A or B, is more readily adsorbed on the column?
Why is sulphide ore of copper heated in a furnace after mixing with silica?
Write down the reactions taking place in Blast furnace related to the metallurgy of iron in the temperature range 500-800 K.
Explain the following:
\[\ce{CO2}\] is a better reducing agent below 710 K whereas \[\ce{CO}\] is a better reducing agent above 710 K.
Explain the following:
Generally sulphide ores are converted into oxides before reduction.
Heating of MgCl2 6H2O in absence of HCl gives ______.
Carbon deposition reaction taking place in ______.
Assertion: For the extraction of iron, haematite ore is used.
Reason: Haematite is a carbonate ore of iron.
