The underlying of blast furnace is made of

The lining of blast furnace is made up of fire clay bricks.

The lining of blast furnace is made up of fire clay bricks.

Inner layer of blast furnace is made of

The inner lining of a blast furnace is made up of

The refractory material used in the lining of blast furnace is

In the extraction of iron, ________ acts as a reducing agent in the upper region of the blast furnace and _________ acts as a reducing agent in the lower region of the blast furnace.