Which element has the largest abundance in the earth’s crust?
Aluminium
Calcium
Magnesium
Sodium
Which of the following ores is an ore of copper?
Argentite
Hematite
Malachite
Calamine
The slag formed in extraction of copper is
CuFeS2
Cu20 + Fe S
Cu2S + FeO
Fe SiO3
The purest zinc is made by
The Mond process
Bessemer process
Zone refining
Electrolytic refining
In forth floatation process for the purification of ores the particles of ore float because.
Their surface is not easily wetted by water.
They are light
They are insoluble
They bear electrostatic charge.
The process of converting hydrated alumina into anhydrous alumina is called
Roasting
Smelting
Dressing
Calcination
Gravity separation process is used for the concentration of
Haematite
Chalcopyrite
Bauxite
