Chile saltpetre is the ore of:

1. Mg

2. K

3. Na

4. Ca

Blast furnace is used in the metallurgy of:

1. Al

2. Fe

3. gold

4. Ag

Liquation is used to purify:

1. Pb

2. Sn

3. Bi

4. All

Wolframite ore contains:

1. Zn

2. W

3. Hf

4. Au

The process in which ore is  heated in limited supply of air below its melting point  is known as:

1. Roasting

2. Calcination

3. Reduction

4. Distillation

Iron is made inactive or passive by:

1. H₃PO₄

2. conc. HNO₃

3. conc. H₂SO₄

4. dil. HNO₃

The inner lining of a blast furnace is  made up of:

1. graphite bricks

2. silica  bricks

3. fire clay bricks

4. basic bricks

Froth floatation process for the concentration of ores is a practical application of:

1. adsorption

2. absorption

3. coagulation

4. sedimentation

Roasting is generally carried out in case of :

1. Oxide ores

2. Sulphide ores

3. Silicate ores

4. Carbonate ores

Which substance is used as basic refractory material in furnace?

1. Al₂O₃

2. SiO₂

3. CaO

4. Fe₂O₃