Pitch blende is an ore of 

  Extraction of the metals from their ores and preparation of alloys is called? 

Sulphide ores are concentrated by

The alloy used in aircraft parts are 

Roasting is generally used for

The impurity present in the ores is 

The material which combines with gangue to form slag is

Haematite is an ore of iron which is chemically

The process in which ore is heated in the absence of air is

 Limestone is