Refractory Technology

171. Upper portion of hot metal mixer are lined with mullite bricks, which helps in resisting the

1. Washing action of metal
2. Corrosion by layer of slag
3. Both (A) & (B)
4. Neither (A) nor (B)

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172. Use of higher percentage of lime for bonding silica bricks, reduces their

1. Strength
2. Abrasion resistance
3. Both (A) & (B)
4. Neither (A) nor (B)

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173. Vacuum steel degassing units are lined with

1. Silica bricks
2. Low duty firebricks
3. High alumina bricks
4. Graphite blocks

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174. Walls, roofs & combustion chambers of annealing furnaces are made of _________ bricks.

1. High duty fireclay
2. Silica
3. Mullite
4. Carborundum

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175. Water content in ground refractory material to be shaped into bricks by hand moulding is about _________ percent.

1. 5
2. 20
3. 40
4. 55

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176. What is the value of 'q' for saturated liquid feed to a distillation column?

1. 0
2. <1
3. 1
4. >1

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177. Which brick undergoes maximum shrinkage on drying?

1. Tar bonded dolomite bricks
2. Fireclay bricks
3. Magnesite bricks
4. Chromite bricks

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178. Which form of silica has the highest specific gravity?

1. Quartz
2. Cristobalite
3. Tridymite
4. All have the same specific gravity

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179. Which furnace consumes maximum refractory annually in an integrated steel plant ?

1. Soaking pit
2. Blast furnace
3. L.D. converter
4. Coke ovens

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180. Which is a basic refractory?

1. Fireclay
2. Silica
3. Chrome magnesite
4. None of these

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