State the principle for each of the following processes which are used in metallurgy in general.
(i) Roasting
(ii) Gravity separation
(iii) Froth flotation
(iv) Aluminothermy
(v) Calcination
(vi) Electromagnetic separation.
State the principle for each of the following processes which are used in metallurgy in general.
(i) Roasting
(ii) Gravity separation
(iii) Froth flotation
(iv) Aluminothermy
(v) Calcination
(vi) Electromagnetic separation.
(i) Roasting: In this process, metal ores are heated in the presence of air. This method is used to extract metals from their sulphide ores.
(ii) Gravity separation: It is based on the differences in densities of ore and gangue particles. Gangue is washed with water, resulting in the concentration of the ore to be obtained.
(iii) Froth flotation: It is based on the preferential wettability of ore and gangue particles. In this method, the gangue particles are removed by agitating the mixture with water, oil and chemicals so as to obtain the concentrated ore. It is usually used to extract metals from their sulphide ores.
(iv) Aluminothermy: In this process, aluminium is added to a metal oxide and the mix is then ignited. This results in the oxidation of aluminium and reduction of metal oxide.
(v) Calcination: In this process, metal ores are heated in the absence of air. This is used to extract metals from their carbonate ores.
(vi) Electromagnetic separation: This process involves the removal of unwanted particles from iron ores through the usage of a magnetic force. Pure metals get easily attracted by the magnetic field, resulting into their separation from the gangue particles.
(i) Roasting: In this process, metal ores are heated in the presence of air. This method is used to extract metals from their sulphide ores.
(ii) Gravity separation: It is based on the differences in densities of ore and gangue particles. Gangue is washed with water, resulting in the concentration of the ore to be obtained.
(iii) Froth flotation: It is based on the preferential wettability of ore and gangue particles. In this method, the gangue particles are removed by agitating the mixture with water, oil and chemicals so as to obtain the concentrated ore. It is usually used to extract metals from their sulphide ores.
(iv) Aluminothermy: In this process, aluminium is added to a metal oxide and the mix is then ignited. This results in the oxidation of aluminium and reduction of metal oxide.
(v) Calcination: In this process, metal ores are heated in the absence of air. This is used to extract metals from their carbonate ores.
(vi) Electromagnetic separation: This process involves the removal of unwanted particles from iron ores through the usage of a magnetic force. Pure metals get easily attracted by the magnetic field, resulting into their separation from the gangue particles.
