61. Hot metal runner in blast furnace are lined with __________ bricks. September 7, 2025 by Admin silica carborundum fireclay magnesite ✅ The correct answer is option C.
62. Magnesite bricks are used in those parts of furnaces, which are September 7, 2025 by Admin subjected to temperature fluctuation. required to resist corrosive basic slag. subjected to high load. none of these. ✅ The correct answer is option B.
63. Dolomite bricks have good resistance to attack by September 7, 2025 by Admin molten steel iron oxide lime slag none of these ✅ The correct answer is option A.
64. Silica bricks are attacked by basic slags at high temperature. Which of the following is not used solely as a binding material? September 7, 2025 by Admin aluminium phosphate water lime plaster of paris ✅ The correct answer is option B.
65. Thermal diffusivity of a refractory brick is high, when its __________ is high. September 7, 2025 by Admin density specific heat thermal conductivity none of these ✅ The correct answer is option C.
66. High alumina refractory compared to fireclay bricks have September 7, 2025 by Admin less load bearing capacity. less resistance to slag attack. low refractoriness. high resistance to thermal shock and creep. ✅ The correct answer is option D.
67. Cold crushing strength of a refractory does not depend upon its September 7, 2025 by Admin shape composition firing temperature texture ✅ The correct answer is option A.
68. Crushing strength of a refractory September 7, 2025 by Admin increases with rise in service temperature. decreases with rise in service temperature. is unaffected with change in service temperature. decreases with increase in porosity. ✅ The correct answer is option B.
69. Which is a basic refractory ? September 7, 2025 by Admin Fireclay Silica Chrome magnesite None of these ✅ The correct answer is option C.
70. Fireclay bricks is not used for lining the September 7, 2025 by Admin cupola. gas producer. bottom of hot metal mixer. roof of open hearth furnace. ✅ The correct answer is option C.