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  • Question
  • Electrical resistor bars are made of


  • Options
  • A. silicon carbide
  • B. alumina
  • C. zirconia
  • D. graphite

  • Correct Answer
  • silicon carbide 


  • Refractory Technology problems


    Search Results


    • 1. Zircon refractories have

    • Options
    • A. low co-efficient of expansion.
    • B. high RUL (1600°C) and refractoriness (> 2000°C).
    • C. high spalling resistance.
    • D. all (a), (b) and (c).
    • Discuss
    • 2. Refractoriness under load (RUL) is the most important property for the refractory bricks

    • Options
    • 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.
    • Discuss
    • 3. Si percentage in silica refractories used in the walls of coke oven is about

    • Options
    • A. 45
    • B. 60
    • C. 80
    • D. 95
    • Discuss
    • 4. The linear thermal expansion of __________ bricks upto 1000 °C is very low of the order of ? 0.5 percent.

    • Options
    • A. fireclay
    • B. silica
    • C. magnesite
    • D. corundum
    • Discuss
    • 5. Fireclay bricks are never used in the

    • Options
    • A. beehive oven
    • B. coke oven walls
    • C. zinc roaster
    • D. lead blast furnace
    • Discuss
    • 6. Maximum safe working temperature for fireclay bricks is about __________ °C.

    • Options
    • A. 1150
    • B. 1300
    • C. 1450
    • D. 1550
    • Discuss
    • 7. Tar bonded dolomite bricks

    • Options
    • 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)
    • Discuss
    • 8. High density refractory bricks have lower

    • Options
    • A. spalling resistance.
    • B. thermal conductivity.
    • C. fusion point.
    • D. slag penetration resistance.
    • Discuss
    • 9. Periclase refractory contains mainly

    • Options
    • A. CaO
    • B. MgO
    • C. Al2O3
    • D. SiO2
    • Discuss
    • 10. Carbon refractory blocks

    • Options
    • A. are wetted by molten iron.
    • B. are used in the hearth of blast furnace.
    • C. are acidic in nature.
    • D. all (a), (b) and (c).
    • Discuss


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