Question: High alumina refractory compared to fireclay bricks have____________________?

• 1. Less load bearing capacity
• 2. Less resistance to slag attack
• 3. Low refractoriness
• 4. High resistance to thermal shock and creep

Question: Porosity of fireclay refractories is _______________ percent?

• 1. 5-10
• 2. 10-25
• 3. 25-35
• 4. 35-50

Question: Fusion temperature of pure silica (SiO2) is _______________ °C?

• 1. 1350
• 2. 1715
• 3. 2570
• 4. 2800

Question: Bottom of basic open hearth furnace are constructed of__________________?

• 1. Dead burnt magnesite ramming mass
• 2. Porous fireclay bricks
• 3. Semi-silica bricks
• 4. Silicon carbide bricks

Question: Addition of zircon to silica refractory brick improves its_____________________?

• 1. Crushing strength
• 2. Resistance to slag attack
• 3. Both A and B
• 4. Neither A nor B

Question: Refractories subjected to alternate cycles of heating & cooling are liable to loose their resistance to__________________?

• 1. Thermal spalling
• 2. Slag attack
• 3. Fusion under load
• 4. CO attack

Question: Refractory bricks with lower permeability is produced by using __________________?

• 1. Higher firing temperature
• 2. Higher moulding pressure
• 3. Finer grog size
• 4. All A, B and C

Question: Pure oxide refractories are generally monocrystalline in nature and are self bonded _______________ bricks are generally used as moderator in nuclear reactors?

• 1. Beryllia
• 2. Carborundum
• 3. Corundum
• 4. Thoria

Question: Ceramic recuperators used for waste heat recovery from high temperature flue gas going out of the furnace is made of________________?

• 1. Fireclay
• 2. Silicon carbide
• 3. Corundum
• 4. Siliceous fireclay

Question: Refractory bricks having lower porosity have_________________________?

• 1. High insulating properties
• 2. Low heat capacity
• 3. Low thermal conductivity
• 4. Greater strength