Water content in ground refractory material to be shaped into bricks by hand moulding is about _____________ percent?

Related Mcqs:

1. An insulating refractory brick should have high porosity and low thermal conductivity. Which of the following is not used for inducing porosity in the insulating refractory bricks during its manufacture ?

   A. Cork
   B. Saw dust
   C. Sand
   D. Chemically prepared foam

2. Maximum alumina content in high alumina refractory can be as high as ____________ percent?

   A. 30
   B. 50
   C. 70
   D. 90

3. Refractory bricks having lower porosity have _____________________?

   A. High insulating properties
   B. Low heat capacity
   C. Low thermal conductivity
   D. Greater strength

4. Refractory bricks with lower permeability is produced by using _________________?

   A. Higher firing temperature
   B. Higher moulding pressure
   C. Finer grog size
   D. All A., B. and C.

5. High porosity refractory bricks have________________?

   A. Poor resistance to the penetration of molten slag, metal & flue gases
   B. Poor heat conductivity & low strength
   C. Better thermal spalling resistance
   D. All A., B. and C.

6. Fusion point of a basic refractory material is________________?

   A. Reduced by the addition of acid oxides
   B. Increased by the addition of acid oxides
   C. Not affected by the addition of acid oxides
   D. Always less than 1000°C

7. N2 content in a urea sample was found to be only 42%. What is the actual urea content of the sample? (Molecular weight of urea = 60) ?

   A. 80%
   B. 90%
   C. 95%
   D. 98%

8. Lower wall courses of soaking pits are made of _____________ bricks to avoid the action of molten slag & scale?

   A. Chrome or magnesite
   B. Silicon carbide
   C. Silica
   D. Low duty fireclay

9. The boiling points for pure water and pure toluene are 100°C and 110.6°C respectively. Toluene and water are completely immiscible in each other. A well agitated equimolar mixture of toluene and water are prepared. The temperature at which the above mixture will exert a pressure of one standard atm. is___________________?

   A. Less than 100°C
   B. 100°C
   C. Between 100 and 110°C
   D. 110.6°C

10. At 100°C, water and methylcyclohexane both have vapour pressures of 1 atm. Also at 100°C, the latent heats of vaporisation of these compounds are 40.63 kJ/mole for water and 31.55 kJ/mole for methylcyclohexane. The vapour pressure of water at 150°C is 4.69 atm. At 150°C, the vapour pressure of methylcyclohexane would be expected to be_________________?

    A. Significantly less than 4.69 atm
    B. Nearly equal to 4.69 atm
    C. Significantly more than 4.69 atm
    D. Indeterminate due to lack of data