MCQOPTIONS
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MCQOPTIONS
This section includes 209 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
*/*_In panel test for spalling resistance, the average face temperature of panel assembly is maintained at __________ °C for 24 hours.? |
| A. | 700 |
| B. | 1000 |
| C. | 1600 |
| D. | 2000 |
| Answer» D. 2000 | |
| 52. |
*/*_Maximum alumina content in high alumina refractory can be as high as __________ percent.? |
| A. | 30 |
| B. | 50 |
| C. | 70 |
| D. | 90 |
| Answer» E. | |
| 53. |
*/*_Spalling resistance of a refractory can not be increased by? |
| A. | Increasing its porosity |
| B. | Using a coarser grog during its manufacture |
| C. | Decreasing its thermal co-efficient of expansion |
| D. | Making it denser |
| Answer» E. | |
| 54. |
*/*_Zirconia refractories are not used in? |
| A. | Making sheaths for thermocouple |
| B. | Lining high temperature ceramic kilns |
| C. | Furnaces subjected to fluctuating temperature |
| D. | High frequency induction furnaces in the form of inductors |
| Answer» D. High frequency induction furnaces in the form of inductors | |
| 55. |
*/*_Upper portion of hot metal mixer are lined with mullite bricks, which helps in resisting the? |
| A. | Washing action of metal |
| B. | Corrosion by layer of slag |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» B. Corrosion by layer of slag | |
| 56. |
*/*_Ramming masses are used for? |
| A. | Obtaining monolithic working faces |
| B. | Repairing construction of various furnace parts |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» D. Neither A nor B | |
| 57. |
*/*_Refractoriness/fusion points of 'superduty' refractories is __________ °C.? |
| A. | 1520-1630 |
| B. | 1630-1670 |
| C. | > 1730 |
| D. | > 2000 |
| Answer» D. > 2000 | |
| 58. |
*/*_Which one contains minimum percentage of SiO‚ÇÇ?? |
| A. | Firebrick |
| B. | Sillimanite |
| C. | Semi-silica |
| D. | Aluminous firebrick |
| Answer» C. Semi-silica | |
| 59. |
*/*_The linear thermal expansion of __________ bricks upto 1000 °C is very low of the order of ≤ 0.5 percent.? |
| A. | Fireclay |
| B. | Silica |
| C. | Magnesite |
| D. | Corundum |
| Answer» B. Silica | |
| 60. |
*/*_Periclase is? |
| A. | Crystalline form of MgO |
| B. | MgCO‚ÇÉ |
| C. | ZrSO‚ÇÑ |
| D. | Amorphous magnesite |
| Answer» B. MgCO‚Äö√á√â | |
| 61. |
*/*_Magnesite chrome refractories? |
| A. | Have better spalling resistance than chrome magnesite refractories |
| B. | Have very low thermal co-efficient of expansion |
| C. | Are not at all resistant to the corrosive action of iron oxide |
| D. | Have very low (50 kg/cm² ) cold crushing strength (C.C.S.), and can not be used in metalcase form |
| Answer» B. Have very low thermal co-efficient of expansion | |
| 62. |
*/*_Which is not an alumino-silicate refractory?? |
| A. | Fireclay bricks |
| B. | Mullite bricks |
| C. | Tar dolomite bricks |
| D. | High alumina bricks |
| Answer» D. High alumina bricks | |
| 63. |
%_Crushing strength of a refractory_% |
| A. | Increases with rise in service temperature |
| B. | Decreases with rise in service temperature |
| C. | Is unaffected with change in service temperature |
| D. | Decreases with increase in porosity |
| Answer» C. Is unaffected with change in service temperature | |
| 64. |
%_Maximum apparent porosity of magnesite bricks is about __________ percent._% |
| A. | 8 |
| B. | 24 |
| C. | 44 |
| D. | 58 |
| Answer» C. 44 | |
| 65. |
%_Tar bonded dolomite bricks_% |
| 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 of the above |
| Answer» E. | |
| 66. |
%___________ of carbon blocks in the hearth of blast furnace helps in avoiding skull formation, when it becomes cold._% |
| A. | High thermal conductivity |
| B. | Low porosity |
| C. | Non-wetting characteristics |
| D. | High density |
| Answer» D. High density | |
| 67. |
%_Periclase is_% |
| A. | Crystalline form of MgO |
| B. | MgCO‚ÇÉ |
| C. | ZrSO‚ÇÑ |
| D. | Amorphous magnesite |
| Answer» B. MgCO‚Äö√á√â | |
| 68. |
%_Ramming masses are used for_% |
| A. | Obtaining monolithic working faces |
| B. | Repairing construction of various furnace parts |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» D. Neither A nor B | |
| 69. |
%_Refractoriness/fusion points of 'superduty' refractories is __________ °C._% |
| A. | 1520-1630 |
| B. | 1630-1670 |
| C. | > 1730 |
| D. | > 2000 |
| Answer» D. > 2000 | |
| 70. |
%_Magnesite chrome refractories_% |
| A. | Have better spalling resistance than chrome magnesite refractories |
| B. | Have very low thermal co-efficient of expansion |
| C. | Are not at all resistant to the corrosive action of iron oxide |
| D. | Have very low (50 kg/cm² ) cold crushing strength (C.C.S.), and can not be used in metalcase form |
| Answer» B. Have very low thermal co-efficient of expansion | |
| 71. |
%_Which is not an alumino-silicate refractory?_% |
| A. | Fireclay bricks |
| B. | Mullite bricks |
| C. | Tar dolomite bricks |
| D. | High alumina bricks |
| Answer» D. High alumina bricks | |
| 72. |
%_Which one contains minimum percentage of SiO‚ÇÇ?_% |
| A. | Firebrick |
| B. | Sillimanite |
| C. | Semi-silica |
| D. | Aluminous firebrick |
| Answer» C. Semi-silica | |
| 73. |
%_The linear thermal expansion of __________ bricks upto 1000 °C is very low of the order of ≤ 0.5 percent._% |
| A. | Fireclay |
| B. | Silica |
| C. | Magnesite |
| D. | Corundum |
| Answer» B. Silica | |
| 74. |
%_Carbon refractories_% |
| A. | Do not burn/oxidise, when exposed to air on heating |
| B. | Are not attacked by slags, as they are not wetted by melts |
| C. | Do not resist temperature fluctuations |
| D. | Have extremely low thermal & electrical conductivities |
| Answer» C. Do not resist temperature fluctuations | |
| 75. |
%_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 |
| Answer» B. Refractoriness | |
| 76. |
%_Skull is not formed on the carbon blocks in the hearth of a blast furnace, when it becomes cold, becaus of its_% |
| A. | Non-wetting characteristic |
| B. | High thermal conductivity |
| C. | High crushing strength |
| D. | None of these |
| Answer» B. High thermal conductivity | |
| 77. |
%_Basic bricks are not made of_% |
| A. | Fireclay |
| B. | Magnesite |
| C. | Foresterite |
| D. | Chromite |
| Answer» B. Magnesite | |
| 78. |
_ Magnesite refractories are generally not used in the$? |
| A. | Electric furnace walls |
| B. | Steel melting furnace |
| C. | Open hearth furnace |
| D. | Burning zone of cement kilns |
| Answer» C. Open hearth furnace | |
| 79. |
_ Zircon refractories have$? |
| A. | Low co-efficient of expansion |
| B. | High RUL (1600°C) and refractoriness (> 2000°C) |
| C. | High spalling resistance |
| D. | All of the above |
| Answer» E. | |
| 80. |
_ Refractoriness under load (RUL) is the most important property for the refractory bricks$? |
| A. | At the hearth bottom of the furnace on which stock is placed |
| B. | Used for furnace insulation |
| C. | Used in the roof of the furnace |
| D. | None of these |
| Answer» B. Used for furnace insulation | |
| 81. |
_ Fireclay refractories$? |
| 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 of the above |
| Answer» E. | |
| 82. |
_ Which is the stable form of silica below 870°C ?$? |
| A. | Tridymite |
| B. | Cristobalite |
| C. | Quartz |
| D. | None of these |
| Answer» D. None of these | |
| 83. |
_ Magnesite bricks are used in those parts of furnaces, which are$? |
| A. | Subjected to temperature fluctuation |
| B. | Required to resist corrosive basic slag |
| C. | Subjected to high load |
| D. | None of these |
| Answer» C. Subjected to high load | |
| 84. |
_ Semi-silica bricks compared to silica bricks have$? |
| A. | Less fusion point |
| B. | Better spalling resistance |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» D. Neither A nor B | |
| 85. |
_ Capacity of a refractory brick to withstand-sudden changes in temperature is denoted by the property called$? |
| A. | Spalling resistance |
| B. | Refractoriness |
| C. | Refractoriness under load (RUL) |
| D. | None of these |
| Answer» B. Refractoriness | |
| 86. |
_ Carbon refractories$? |
| A. | Do not burn/oxidise, when exposed to air on heating |
| B. | Are not attacked by slags, as they are not wetted by melts |
| C. | Do not resist temperature fluctuations |
| D. | Have extremely low thermal & electrical conductivities |
| Answer» C. Do not resist temperature fluctuations | |
| 87. |
_ Chrome magnesite bricks are$? |
| A. | Acidic in nature |
| B. | Neutral in nature |
| C. | Having higher RUL than silica bricks |
| D. | Made by mixing 30% chromite and 70% periclase |
| Answer» D. Made by mixing 30% chromite and 70% periclase | |
| 88. |
_ The maximum linear expansion of silica bricks during firing is about __________ percent.$? |
| A. | 0.5 |
| B. | 1 |
| C. | 2 |
| D. | 3.5 |
| Answer» E. | |
| 89. |
_ The main raw material for manufacture of silicon carbide refractories is$? |
| A. | Corrundum |
| B. | Carborundum |
| C. | Bauxite |
| D. | Periclase |
| Answer» C. Bauxite | |
| 90. |
_ Electrical resistor bars are made of$? |
| A. | Silicon carbide |
| B. | Alumina |
| C. | Zirconia |
| D. | Graphite |
| Answer» B. Alumina | |
| 91. |
_ Machine moulding of dry mixture of refractories requires a pressure of the order of __________ kg/cm².$? |
| A. | 10 |
| B. | 100 |
| C. | 500 |
| D. | 1000 |
| Answer» E. | |
| 92. |
_ Faster rate of drying of moulded refractories results in high __________ of refractories.$? |
| A. | Green strength |
| B. | Voids |
| C. | Shrinkage |
| D. | Both B and C |
| Answer» E. | |
| 93. |
__Which of the following is not an acidic refractory?__ |
| A. | Silica bricks |
| B. | Fireclay bricks |
| C. | Bauxite bricks |
| D. | Magnesia bricks |
| Answer» E. | |
| 94. |
__Cold crushing strength of refractories depends upon its__ |
| A. | Composition |
| B. | Texture |
| C. | Firing temperature |
| D. | All of the above |
| Answer» E. | |
| 95. |
__PCE value (Segar cone) of superduty refractories is more than 33, which is equivalent to a temperature of __________ °C.__ |
| A. | 1520 |
| B. | 1630 |
| C. | 1670 |
| D. | 1730 |
| Answer» E. | |
| 96. |
__Outer combustion chamber of blast furnace stove is lined with __________ bricks.__ |
| A. | Fireclay |
| B. | Silica |
| C. | Chrome magnesite |
| D. | Zirconia |
| Answer» B. Silica | |
| 97. |
__Mixing of ground refractory material and water is done in a __________ mill.__ |
| A. | Pug |
| B. | Ball |
| C. | Tube |
| D. | Rod |
| Answer» B. Ball | |
| 98. |
__Which brick undergoes maximum shrinkage on drying?__ |
| A. | Tar bonded dolomite bricks |
| B. | Fireclay bricks |
| C. | Magnesite bricks |
| D. | Chromite bricks |
| Answer» C. Magnesite bricks | |
| 99. |
__Bauxite calcining rotary kilns are lined with __________ bricks.__ |
| A. | Fireclay |
| B. | Carbon |
| C. | 85% alumina |
| D. | Corundum |
| Answer» D. Corundum | |
| 100. |
____________ is the measure of the strength of refractory under the combined effect of temperature & load.__ |
| A. | Porosity |
| B. | RUL |
| C. | Specific gravity |
| D. | Thermal conductivity |
| Answer» C. Specific gravity | |