6. Hindered settling condition favors

a) Classification according to size

b) Classification according to specific gravity

c) Separation of slime

d) Thickening of pulp.

7. Matte is a

a) Solid solution of sulphides

b) Liquid solution of oxides and sulphides

c) Liquid solution of metal sulphides

d) Solid solution of sulphides and arsenides.

8. Horizontal retort is used for production of zinc. Choose the correct ones from the following

a) The retort is made of clay

b) The input materials are heated above the boiling point of zinc.

c) The retort is made of metal

d) The input materials are heated upto the melting point of zinc

9. The output of Zn-retort process is

a) Liquid Zn +residue

b) Zn vapour + residue

c) Residue only

d) Spelter + residue

10. In imperial smelting process

a) Molten lead is used to condense zinc vapors

b) Lead and zinc both can be produced

c) Liquid zinc is produced

d) Molten tin is used to condense zinc vapors