Q15 of 26 Page 1

(i) Write the name of method of refining Ni.

(ii) What is the role of cryolite in the extraction of Aluminium?


(iii) Write one difference between Roasting and Calcination.


(i) Name of method of refining Ni is Mond’s process.


In this process crude Ni is heated in a stream of CO to form volatile nickel carbonyl. That nickel carbonyl is then subjected to high temperature to get pure Ni.



(ii) Role of cryolite in the extraction of Aluminium is that it decreases the melting point and increases the fusibilityof alumina.


(iii) One difference between Roasting and Calcination is that roasting is done in a free supply of air, below the melting point of metal and calcinations is done in a limited supply of air so that all volatile impurities can escape.


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