1. . Silica refractories are not used in:
(A) Coke oven walls
(B) Beehive coke ovens
(C) Dome and upper portion of B.F. stoves
(D) Open hearth furnace
2. . Si percentage in silica refractories used in the walls of coke oven is about:
(A) 45
(B) 60
(C) 80
(D) 95
3. . Porosity of silica bricks varies from:
(A) 5 to 10
(B) 20 to 30
(C) 45 to 60
(D) 60 to 75
4. . Chrome magnesite bricks are:
(A) Acidic in nature
(B) Neutral in nature
(C) Having higher RUL than silica bricks
(D) Made by mixing 30% Chromite and 70% Periclase
5. . Alumina-graphite bricks are used for lining the:
(A) Slide gate in teeming ladles
(B) Continuous casting systems
(C) Both (a) and (b)
(D) Neither (a) nor (b)
6. . Maximum shrinkage in volume during firing of dried refractories may be as high as:
(A) 10
(B) 15
(C) 20
(D) 30
7. . The main raw material for manufacture of silicon carbide refractories is:
(A) Corundum
(B) Carborundum
(C) Bauxite
(D) Periclase
8. . Which consumes the maximum tonnage of refractories annually in an integrated steel plant?
(A) Soaking pits
(B) Reheating furnace
(C) L.D. converter
(D) Rotary lime kiln
9. . Upper portion of hot metal mixer lined with mullite bricks helps in resisting:
(A) Washing action of metal
(B) Corrosion by slag
(C) Both (a) & (b)
(D) Neither (a) nor (b)
10. . Lower part of hot metal mixer is lined with:
(A) Superduty fireclay
(B) High alumina
(C) Silica
(D) Carborandum