The impurities like sand, limestone and mica are called…………….
a) gangue
b) ore
c) salt
d) paints
Huge lumps of ores broken into small pieces with the help of …………..
a) crusher
b) grinder
c) hammer
d) both a & b
Ores are broken into small pieces and these pieces are then reduced to fine powder with the help of a……………..
a) ball mill
b) stamp mill
c) both a & b
d) none of these
The ores are concentrated to sufficient degree of purify by simply picking it with hand and breaking the rock stone with hammer is called
a) hand picking
b) froth floatation
c) hydraulic washing
d) crushing
…………method is based on the difference in densities of the ore and gangue.
a) froth floatation
b) hand packing
c) grinding
d) hydraulic washing
In….……method the denser ore settles in the groove while the lighter gangue particles are washed away.
a) leaching
b) electrolysis
c) roasting
d) hydraulic washing
