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Chemical Engineering :: Refractory Technology

  1. The main raw material for manufacture of silicon carbide refractories is

  2. A.
    corrundum
    B.
    carborundum
    C.
    bauxite
    D.
    periclase

  3. Chromite refractories are used in

  4. A.
    bottom of soaking pits.
    B.
    between acid & basic linings in basic open hearth furnaces to prevent their chemical action with each other.
    C.
    both (a) & (b)
    D.
    neither (a) and (b)

  5. Which of the following has the lowest electrical resistivity ?

  6. A.
    Graphite
    B.
    Fireclay
    C.
    Alumina
    D.
    Zircon

  7. Dry mix hydraulic compositions of refractory aggregates with suitable bonding materials are called refractory

  8. A.
    mortars
    B.
    cements
    C.
    castables
    D.
    none of these

  9. Silica bricks have low spalling resistance below 600°C, due to its

  10. A.
    very high thermal conductivity.
    B.
    high co-efficient of expansion upto this temperature.
    C.
    high thermal diffusivity.
    D.
    low refractoriness.

  11. Tar dolomite bricks are used in the

  12. A.
    basic Bessemer converter
    B.
    basic open hearth furnace
    C.
    electric furnaces
    D.
    all (a), (b) and (c)

  13. Pick out the wrong statement.

  14. A.
    Electrical conductivity of refractory is not important, when these are to be used in electrical furnaces.
    B.
    Graphite and metals are the good electrical conductor among the refractories and others are all electrical insulators.
    C.
    Refractories used for lining electrical furnaces should ordinarily have very low electrical conductivity.
    D.
    Electrical conductivity of porous refractory material is low.

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

  16. A.
    Soaking pit
    B.
    Blastfurnace
    C.
    L.D. converter
    D.
    Coke ovens

  17. Lower part of hot metal mixer are lined with __________ bricks.

  18. A.
    superduty fireclay
    B.
    high alumina
    C.
    silica
    D.
    carborundum

  19. Pick out the wrong statement.

  20. A.
    Sand & coke is the main raw material for the manufacture of silicon carbide.
    B.
    Carbon refractories can not be used in the furnaces operating under reducing conditions.
    C.
    Mullite can be obtained by the heating of alusite, kyanite or silimanite.
    D.
    Silica occurs in nature in all cellular, amorphous or crystalline form.