A. Reduction with carbon B. Reduction with aluminium C. Reduction with hydrogen D. Electrolytic method

A. Carbon filters B. Compressed air C. Limestone D. Sulphuric acid

A. Magnetic treatment B. Froth floatation C. Electrolysis D. Roasting

A. Calamine B. Pitch blende C. Cryolite D. None

A. Concentration B. Refining C. Smelting D. None of these