41. Chrome magnesite bricks are used in the side walls of soaking pits and arc furnaces. copper melting furnaces & converters. burner block of glass tanks. all (a), (b) and (c) ✅ The correct answer is option D.
42. With increase in the porosity, thermal spalling resistance of fireclay brick increases decreases remains same may increase or decrease ✅ The correct answer is option A.
43. Zircon refractories have low co-efficient of expansion. high RUL (1600°C) and refractoriness (> 2000°C). high spalling resistance. all (a), (b) and (c). ✅ The correct answer is option D.
44. Which is an acidic refractory ? Magnesite Dolomite Fireclay Chrome magnesite ✅ The correct answer is option C.
45. Segar cones are used for the determination of __________ of refractories. softening temperature spalling resistance electrical conductivity resistance to slag attack ✅ The correct answer is option A.
46. With increase in the alumina content in firebricks, its fusion point (refractoriness) decreases linearly remains unchanged increases decreases ✅ The correct answer is option C.
47. Pure oxide refractories are generally monocrystaliine in nature and are self bonded __________ bricks are generally used as moderator in nuclear reactors. Beryllia Carborundum Corundum Thoria ✅ The correct answer is option A.
48. Except __________ , all other refractories are bad conductors of electricity (i.e, have low electrical conductivity). fireclay carborundum graphite chromite ✅ The correct answer is option C.
49. An ideal refractory should have high spalling rate fusion point shrinkage ability none of these ✅ The correct answer is option B.
50. Which of the following bricks has the most close values of RUL and PCE ? Silica bricks Fireclay bricks High alumina bricks Tar dolomite bricks ✅ The correct answer is option A.