Chemical Engineering - Refractory Technology
Exercise :: Refractory Technology - Section 3
| 36. |
Pick out the wrong statement. |
| A. |
A ceramic material which becomes fluid upon heating and can be moulded in liquid/viscous state is termed s glass. | | B. |
Ceramic materials do not undergo vitrification on heating. | | C. |
Ceramic materials are brittle in nature. | | D. |
Non-oxide ceramic materials generally act as a semi-conductor. |
Answer: Option B
Explanation:
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| 37. |
Lower wall courses of soaking pits are made of __________ bricks to avoid the action of molten slag & scale. |
| A. |
chrome or magnesite | | B. |
silicon carbide | | C. |
silica | | D. |
lowduty fireclay |
Answer: Option A
Explanation:
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| 38. |
Addition of grog in fireclay brick during its manufacture is advantageous, because it results in |
| A. |
less shrinkage in heating, decreased apparent porosity & increased specific gravity. | | B. |
high strength & thermal spalling resistance. | | C. |
less addition of water to get a workable plasticity & lesser time required for drying the raw refractories and hence increased rate of production. | | D. |
all (a), (b) and (c). |
Answer: Option D
Explanation:
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| 39. |
Slide gates in teeming laddie used for steel pouring in ingot moulds is lined with __________ bricks. |
| A. |
bakelite impregnated or fused periclase | | B. |
silica | | C. |
semi-silica | | D. |
fireclay |
Answer: Option A
Explanation:
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| 40. |
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 (a), (b) and (c) |
Answer: Option D
Explanation:
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