Concentration of sulphide ore is done by
  • froth flotation process
  • electrolysis
  • roasting
  • None of these
Malachite is an ore of
  • iron
  • copper
  • zinc
  • Sliver
Ore of aluminium is
  • bauxite
  • hematite
  • dolomite
  • None of these
Removal of the unwanted materials like sand, clays, etc. from the ore is known as ………., …….. or ……….
  • concentration, dressing, benefaction
  • separation, refining, gangue
  • magnetic separation, purification, gangue
  • washing, refining, amalgamation
For which of the following ores froth floatation method is used for concentration?
  • Haematite
  • Zinc blende
  • Magnetite
  • Camallite
The powdered ore is agitated with water or washed with running stream of water. The heavy ore particles and lighter impurities are separated. This method of concentration is known as
  • metallurgy
  • leaching
  • froth floatation process
  • gravity separation
The oil used as frothing agent in froth floatation process is
  • coconut oil
  • castor oil
  • palmitic oil
  • pine oil
Which of the following metals is not extracted by leaching?
  • Aluminium
  • Mercury
  • Silver
  • Gold
Sulphide ore of zinc/copper is concentrated by
  • floatation process
  • electromagnetic process
  • gravity separation
  • distillation
Which of the following ores is concentrated by chemical leaching method?
  • Cinnabar
  • Argentite
  • Copper pyrites
  • Galena
How do we separate two sulphide ores by froth floatation method?
  • By using excess of pine oil
  • By adjusting proportion of oil to water or using depressant.
  • By using some solvent in which one of the sulphides is soluble
  • By using collectors and froth stabilisers like xanthates
Common impurities present in bauxite are
  • CuO
  • ZnO
  • CaO
  • SiO
An ore of tin containing FeCrO
  • gravity separation
  • magnetic separation
  • froth floatation
  • leaching
Which of the following ores cannot be concentrated by magnetic separation?
  • Haematite
  • Malachite
  • Magnetite
  • Siderite
Which of the following metals is extracted using a silica lined convertor?
  • Mg
  • Al
  • Cu
  • Zn
Which of the following sulphides when heated strongly in air gives the corresponding metal without undergoing separate reduction of oxide?
  • Cu
  • FeS
  • HgS
  • ZnS
Which of the following metals cannot be obtained by reduction of its metal oxide bv aluminium ?
  • Cr
  • Mn
  • Fe
  • Mg
Heating pyrites to remove sulphur is called
  • smelting
  • calcination
  • liquation
  • roasting
Impurities of sulphur, silicon and phosphorus can be removed from cast iron by adding
  • carbon which reduces the impurities
  • water which dissolves the impurities
  • limestone which changes impurities into oxides and pass into slag
  • iron oxide which reacts with impurities by forming slag
In metallurgical process, aluminium acts as
  • an oxidising agent
  • a reducing agent
  • acidic flux
  • basic flux
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