Gravity separation process is used for the concentration of:
calamine
haematite
chalcopyrite
bauxite
In Mc Arthur forest method, silver is extracted from the solution of Na[Ag(CN)2] by the use of:
Fe
Mg
Cu
Zn
Which of the following is not an ore of magnesium?
Magnesite
Dolomite
Gypsum
Carnallite