QUESTION $2$

a$)$ A copper concentrate assaying $($weight $\%)$: $30\%$ Cu; $22\mathrm{.}5\%$ S; $26\mathrm{.}2\%$ Fe and $21\mathrm{.}3\%$ gangue is roasted to $12\mathrm{.}5\%$ S$.$ Calculate the weight of the calcine based on $100$kg of concentrate?

b$)$ Give reasons for drying mineral concentrates?

c$)$ Identify the methods used for agglomeration of minerals?

d$)$ Describe the Mond Carbonyl process for refining of Ni$,$ use chemical equations?

QUESTION $3$

a$)$ The refining of lead bullion follows a sequence of processes. Describe the following processes used to remove metallic impurities:

i$.$ Liquation?

ii$.$ Drossing?

iii. Softening?

Iv$.$ Desilvering $($Parkes process$)?$

b$)$ Explain why the Ellingham curve for the formation of HgO shows a steep rise at $356\backslash$deg C$?$

c$)$ Al reduces $$Cr$\_2$ O$\_3$ to Cr$.$ What is the AG$\backslash$deg for the reaction?

d$)$ What are the main objectives of matte smelting?