Refractory Technology Mcqs for Chemical - Set 7

1)   High refractoriness of refractory bricks means, that it has a________________?

a. High spalling resistance
b. Low spalling resistance
c. High resistance to fusion
d. Low porosity
Answer  Explanation 

ANSWER: High resistance to fusion

Explanation:
No explanation is available for this question!


2)   To resist spalling tendency, a refractory should have________________?

a. Greater diffusivity
b. Low specific heat
c. Low thermal co-efficient of expansion
d. All A., B. and C.
Answer  Explanation 

ANSWER: All A., B. and C.

Explanation:
No explanation is available for this question!


3)   Cermets are____________________?

a. Composite material containing both ceramic & metallic constituents
b. Having high strength & resistance to high temperature
c. Used in space vehicles, missiles & nuclear energy plants
d. All A., B. and C.
Answer  Explanation 

ANSWER: All A., B. and C.

Explanation:
No explanation is available for this question!


4)   Dry mix hydraulic compositions of refractory aggregates with suitable bonding materials are called refractory_________________?

a. Mortars
b. Cements
c. Castables
d. None of these
Answer  Explanation 

ANSWER: Castables

Explanation:
No explanation is available for this question!


5)   Hot face insulating linings of high purity alumina fused mullite are used, where_________________?

a. Very high temperatures are involved
b. Highly reducing conditions are involved
c. Presence of iron or silica is harmful
d. All A., B. and C.
Answer  Explanation 

ANSWER: All A., B. and C.

Explanation:
No explanation is available for this question!


6)   Periclase refractory contains mainly________________?

a. CaO
b. MgO
c. Al2O3
d. SiO2
Answer  Explanation 

ANSWER: MgO

Explanation:
No explanation is available for this question!


7)   Silica bricks have low spalling resistance below 600°C, due to its________________?

a. Very high thermal conductivity
b. High co-efficient of expansion upto this temperature
c. High thermal diffusivity
d. Low refractoriness
Answer  Explanation 

ANSWER: High co-efficient of expansion upto this temperature

Explanation:
No explanation is available for this question!


8)   Magnesite refractories have low resistance to___________________?

a. Attack by basic slag
b. Abrasion
c. Disintegration on sudden change of temperature
d. Both B. and C.
Answer  Explanation 

ANSWER: Both B. and C.

Explanation:
No explanation is available for this question!


9)   Which is a basic refractory ?

a. Fireclay
b. Silica
c. Chrome magnesite
d. None of these
Answer  Explanation 

ANSWER: Chrome magnesite

Explanation:
No explanation is available for this question!


10)   Tar dolomite bricks are used in the_________________?

a. Basic Bessemer converter
b. Basic open hearth furnace
c. Electric furnaces
d. All A., B. and C.
Answer  Explanation 

ANSWER: All A., B. and C.

Explanation:
No explanation is available for this question!


11)   Cold crushing strength of fireclay bricks is about ______________ kgf/cm2?

a. 50-100
b. 100-150
c. 200-400
d. 500-1000
Answer  Explanation 

ANSWER: 200-400

Explanation:
No explanation is available for this question!


12)   Sillimanite (Al2O3.SiO2) refractory, which is a neutral refractory, is not used in________________?

a. Pottery furnace
b. Glass melting furnace
c. Crucibles
d. Gas retorts
Answer  Explanation 

ANSWER: Gas retorts

Explanation:
No explanation is available for this question!


13)   Rate of slag attack on refractories increases with rise in temperature due to the___________________?

a. Decreased viscosity of slag
b. Increased thermal conductivity of brick
c. Oxidising condition in the furnace
d. None of these
Answer  Explanation 

ANSWER: Decreased viscosity of slag

Explanation:
No explanation is available for this question!


14)   Tar bonded dolomite bricks__________________?

a. Are stored under controlled temperature & humidity to avoid hydration
b. Are used in outer lining of L.D. converters
c. Have poorer hydration resistance than pitch bonded bricks
d. All A., B. and C.
Answer  Explanation 

ANSWER: All A., B. and C.

Explanation:
No explanation is available for this question!


15)   Which furnace consumes maximum refractory annually in an integrated steel plant ?

a. Soaking pit
b. Blast furnace
c. L.D. converter
d. Coke ovens
Answer  Explanation 

ANSWER: L.D. converter

Explanation:
No explanation is available for this question!


16)   Which of the following bricks should not be used, if the furnace is to be used intermittently ?

a. Firebricks
b. Silica bricks
c. Silicon carbide bricks
d. Sillimanite
Answer  Explanation 

ANSWER: Silica bricks

Explanation:
No explanation is available for this question!


17)   Refractoriness under load (RUL) is the most important property for the refractory bricks_________________?

a. At the hearth bottom of the furnace on which stock is placed
b. Used for furnace insulation
c. Used in the roof of the furnace
d. None of these
Answer  Explanation 

ANSWER: At the hearth bottom of the furnace on which stock is placed

Explanation:
No explanation is available for this question!


18)   Ganister is a source of the ________________?

a. Silica
b. Periclase
c. Lime
d. None of these
Answer  Explanation 

ANSWER: Silica

Explanation:
No explanation is available for this question!


19)   Which is required in an insulating refractory ?

a. High thermal conductivity
b. Low porosity
c. Both A. and B.
d. Neither A. nor B.
Answer  Explanation 

ANSWER: Neither A. nor B.

Explanation:
No explanation is available for this question!


20)   Sillimanite is a _____________ refractory?

a. Basic
b. Neutral
c. High alumina
d. Insulating
Answer  Explanation 

ANSWER: High alumina

Explanation:
No explanation is available for this question!