11. Answer the following in two or three sentences

i) Write down the ore minerals of copper, zinc, lead and nickel.

ii) What is the role of scrap iron in lead blast furnace smelting?

iii) Why is it necessary to smelting concentrate in two/three stages?

iv) Write down the anodic and cathodic reactions in the electro winning of copper.

v) Though it is possible to dehydrate aluminium hydroxide at , the calcination is done at .

vi) What is the purpose of poling in fire-refining of copper?

vii) What is cryolite ratio in Hall-Heroult bath?

viii) Why is it not possible to used high silica bauxite for the Bayer process?

ix) While galena and sphalerite concentrates are dead roasted but not the chalcopyrite concentrate. Give reasons.

x) Distinguish between kroll and Hunter processes of titanium production.

xi) Name aluminium production plants and their locations in India?

xii) Why is it not possible to produce Al by reduction smelting?

   
12) A copper converter treats per charge 10tons of 40%  matte. Blast is furnished at the r at of 100CU.M. per minute. Before adding flux a preliminary blow of 9 min. is given to produce a magnetite coating, which analyzes as  and unoxidized constituents 15%. Assume that this is entirely corroded by the . The flux carries .

The blister copper is . The converter gases carry no free oxygen.