Metallurgy

I) Calcination: Calcination involves heating of the ore in the absence of air and the ________ escapes leaving behind the metal oxide.

________: This is useful for low boiling metals like zinc and mercury containing high boiling point metals as impurities.

Naturally occurring sources from which a metal or valuable mineral can be extracted profitably.

________: In this process low melting metal like tin can be made to flow on a sloppy surface.

D. Leaching: Leaching is often used if the ore alone but not the gangue is soluble in some ________.

________ of the gangue from the ore is known as Concentration /dressing /benefaction.

Hydraulic washing is a type of gravity separation, which is based on gravity differences between the ore and the gangue particles

The ________ are washed away and the heavier ore particles are left behind.

In this process an upward stream of running water is used to wash the powdered ore

Magnetic separation is a method of waste management where magnets are used to separate metal from refuse.

Iron ores

Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic. Froth is used in this process.

Sulphide Ores

Leaching is often used if the ore alone but not the gangue is soluble in some suitable solvent.

Leaching of Alumina (Al2O3) from Bauxite

Calcination involves heating of the ore in the absence of air and the volatile matter escapes leaving behind the metal oxide.

ZnCO3→ ZnO+ CO2(g)

Roasting involves heating of the ore in a regular supply of air.

2ZnS+3O2→ 2ZnO+ 2SO2

MxOy+ yC→ xM+ yCO

extracted metal is distilled to obtain the pure metal as distillate.

In this process low melting metal like tin can be made to flow on a sloping surface and is separated from high melting impurities.

The molten metal is stirred with logs of green wood.

Impure metal as anode and pure metal as cathode with the salt of the same metal as an electrolyte.