Maximum apparent porosity of magnesite bricks is about _____________ percent?

Related Mcqs:

1. 10 to 30% magnesite is added to Chromite to produce chrome-magnesite refractories. Magnesite addition is mainly done to improve the _____________ of Chromite?

   A. Spalling resistance
   B. Refractoriness
   C. Crushing strength
   D. Resistance to slag

2. Porosity of silica bricks varies from ______________ percent?

   A. 5 to 10
   B. 20 to 30
   C. 45 to 60
   D. 60 to 75

3. Firing temperature of magnesite bricks is about _____________ °C?

   A. 800-1000
   B. 1000-1200
   C. 1600-1800
   D. 2400-2600

4. Magnesite bricks have poor resistance to attack by _____________ slag?

   A. Lime
   B. Basic
   C. Acid
   D. None of these

5. 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

6. Chrome magnesite bricks are used in the_________________?

   A. Side walls of soaking pits and arc furnaces
   B. Copper melting furnaces & converters
   C. Burner block of glass tanks
   D. All A., B. and C.

7. Magnesite chrome bricks are used in the___________________?

   A. Roof lining of basic open hearth & other basic furnaces
   B. Reheating furnaces
   C. Soaking pits
   D. All A., B. and C.

8. Which of the following impurities reduces the refractoriness of magnesite bricks ?

   A. Al2O3
   B. CaO
   C. SiO2
   D. All A., B. & C.

9. Magnesite bricks are used in those parts of furnaces, which are __________________?

   A. Subjected to temperature fluctuation
   B. Required to resist corrosive basic slag
   C. Subjected to high load
   D. None of these

10. 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.