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
D.
Zn
In Mc Arthur Forest method, silver is extracted from the solution of sodium agenticyanide by using zinc.
2Na[Ag(CN)2] + Zn → Na2[Zn(CN)4] + 2Ag ↓