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Chemical Engineering :: Refractory Technology

  1. Bottom of basic open hearth furnace are constructed of

  2. A.
    dead burnt magnesite ramming mass.
    B.
    porous fireclay bricks.
    C.
    semi-silica bricks.
    D.
    silicon carbide bricks.

  3. Which form of silica has the highest specific gravity ?

  4. A.
    Quartz
    B.
    Cristobalite
    C.
    Tridymite
    D.
    All have the same specific gravity

  5. Ceramic recuperators used for waste heat recovery from high temperature flue gas going out of the furnace is made of

  6. A.
    fireclay
    B.
    silicon carbide
    C.
    corrundum
    D.
    siliceous fireclay

  7. __________ is the measure of the strength of refractory under the combined effect of temperature & load.

  8. A.
    Porosity
    B.
    RUL
    C.
    Specific gravity
    D.
    Thermal conductivity

  9. Fireclay bricks are not used in the

  10. A.
    blast furnace
    B.
    hot blast stove
    C.
    cupola
    D.
    wall of coke oven

  11. Pick out the wrong statement.

  12. A.
    A ceramic material which becomes fluid upon heating and can be moulded in liquid/viscous state is termed s glass.
    B.
    Ceramic materials do not undergo vitrification on heating.
    C.
    Ceramic materials are brittle in nature.
    D.
    Non-oxide ceramic materials generally act as a semi-conductor.

  13. Lower wall courses of soaking pits are made of __________ bricks to avoid the action of molten slag & scale.

  14. A.
    chrome or magnesite
    B.
    silicon carbide
    C.
    silica
    D.
    lowduty fireclay

  15. Addition of grog in fireclay brick during its manufacture is advantageous, because it results in

  16. A.
    less shrinkage in heating, decreased apparent porosity & increased specific gravity.
    B.
    high strength & thermal spalling resistance.
    C.
    less addition of water to get a workable plasticity & lesser time required for drying the raw refractories and hence increased rate of production.
    D.
    all (a), (b) and (c).

  17. Slide gates in teeming laddie used for steel pouring in ingot moulds is lined with __________ bricks.

  18. A.
    bakelite impregnated or fused periclase
    B.
    silica
    C.
    semi-silica
    D.
    fireclay

  19. Fireclay refractories

  20. A.
    are not resistant to the action of basic slags.
    B.
    combine with salts (e.g. chlorides sulphates etc.) & bases (e.g. lime, magnesia etc.) forming fusible aluminates silicates etc.
    C.
    shrink during firing
    D.
    all (a), (b) and (c)