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self evaluation
self evaluation
1.Stannite deposits constitute an important source for which of the following metal
a) Thorium
b) Titanium
c) Molybdenum
d) Tin
- In mineral beneficiation
a) Mineral is separated
b) Particles containing mineral are separated
c) Mineral is concentrate
d) Tailing are separated
- The imperial smelting process for Zinc employs
a) Horizontal retort
b) Blast furnace
c) Rotary kiln
d) Laser beam
- The Pidgeo is process for magnesium production uses
a) Carbon
b) Aluminum
c) Hydrogen
- Ferro-silicon
- The highest roasting rate is achieved in a
a) Hearth roaster
b) Blast roaster
c) Flash roaster
- Shaft roaster
- Hindered settling condition favors
a) Classification according to size
b) Classification according to specific gravity
c) Separation of slime
d) Thickening of pulp.
- 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.
- Horizontal retort is used for production of zinc. Choose the correct ones from the following
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?
- 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.
Required:
a) The weight of magnetite coating produced, flux required and slag made.
b) The weight of blister copper, and the % of copper recovery
c) The blowing time of each stage.
d) The volume and % composition of the converter gases.
- A cupola melts per hour 15 tons of pig iron of composition of scrap containing. C 3.5%, Si 2.2% Mn 0.8% and PO.7%, and 5 ton of scarp containing C 3,%, Si1.8% Mn 1.1% and P O.2%.
The dry air used is measured at 313K to melt 1ton of pig iron and scrap per minute.
During melting 20% of total Si charged, 15% of total Mn charged 1% of total Fe charged and 5% of
C is oxidized,19% of carbon of coke is absorbed by iron during milting. Enough is charged to give 30% CaO in slag. The coke is 92% C and 8% SiO 2 and weight of coke is 1/9 of the total weight of pig iron and scrap.
Required:
a) Charge balances of cupola for 5 hr run.
b) The % composition of resulting cast iron, slag and gases.
A plant treats 210 tonnes of material in a shift of metal grade 40% and tailing has metal grade 0.2%. Calculate mass of concentrate and tailing.
A roasted lead ore is smelted in a blast furnace with enough to make a slag of 18.5% CaO
.The coke is 16% of the roasted ore and analyzes 90% C and. The composition of roasted
ore;. Of the lead charged 5% is lost in dust andflue, and 8% enters the matte. Of the copper charged 50 % enters the matte and rest copper enters into lead bullion .Ten % of S enters into gases.
Find: Per 1000Kg roasted ore
The amounts of lead bullion, matte and
- Regenerator receives hot flue gases at and cold air at , the flue gases leave at and the air is preheated to. As estimated 15% of the heat given up by the flue gases is heat lost to the regenerator surroundings, and the rest (85%) is recovered in the preheated air. It may be assumed for estimating purposes that for flue gases and for air, independent of temperature. Estimate over all thermal efficiency, efficiency limit, and relative efficiency for this heat exchange operation.
Suppose now that the depth of the regenerator is increased to 2.5 times in such a way to double the
heat exchange area while keeping constant the over-all heat transfer coefficient .The quantities and entering temperatures of the flue gases and air will be kept the same. Heat losses are same as that in a). Estimate for the enlarged regenerator (a) air preheat temperature, (b) over-all thermal
