1. What is wet process?
a) Grinding and mixing of the raw materials in their dry state
b) Grinding and mixing of the raw materials in their medium state
c) Grinding and mixing of the raw materials in their wet state
d) Grinding and mixing of the raw materials in their overheated state
Explanation: Grinding and mixing of the raw materials in their wet state is called wet process and grinding and mixing of the raw materials in their dry state is called dry process.
2. What is the moisture content in slurry for wet process?
a) 35-50%
b) 12%
c) 40-45%
d) 100%
Explanation: The moisture content in slurry for wet process is 35-50%. 12% is the moisture content for dry process.
3. Size of the kiln needed to manufacture the cement is bigger for wet process.
a) True
b) False
Explanation: The kiln size is bigger for wet process than for dry process to manufacture the cement because much of the kiln’s length was used up for the drying process.
4. Among the below statement, which one is correct for wet process?
a) The amount of heat required is high, so the required fuel amount is high
b) The amount of heat required is lesser, so the required fuel amount is less
c) The amount of heat required is high, so the required fuel amount is less
d) The amount of heat required is less, so the required fuel amount is high
Explanation: The amount of heat required is higher, so the required fuel amount is higher for wet process and vice-versa for dry process.
5. The slurry with the desired lime content passes into the _____
a) Clinker
b) Rotary kiln
c) Slurry tank
d) Cement silo
Explanation: The slurry with the desired lime content passes into the rotary kiln up to 8 m in diameter and length 230m.
6. The slurry, in its movement down the kiln, encounters a progressively higher temperature. At first, the water is driven off and ___ is liberated.
a) SiO2
b) CO2
c) Gypsum
d) CaO
Explanation: At 900°C limestone decomposes, CaCO3.CaO + CO2 (endothermic reaction) CO2 is swept away by current air.
7. The machinery and equipments do not need much maintenance.
a) True
b) False
Explanation: In wet process, raw materials can be mixed easily and therefore we don’t need any extra energy and due to this machinery and equipments do not need much maintenance.
8. When chalk is used _______
a) It is finely broken up and dispersed in water in a wash mill
b) It has to be blasted, then crushed, usually in two progressively smaller crushers
c) It is sieved and fed into a rotating dish called a granulator
d) The raw materials are crushed and fed into a grinding mill, where they are dried and reduced into fine powder
Explanation: When chalk is used, it is finely broken up and dispersed in water in a wash mill. Similarly, the clay is also broken up and mixed with water, usually in a similar wash mill.
9. In the wet process, the kiln is ___________
a) Horizontal
b) Vertical
c) Slightly inclined with vertical
d) Slightly inclined with horizontal
Explanation: The kiln is slightly inclined with horizontal so that the slurry coming from slurry tank can free fall with the gravity into the next process.
10. In the wet process of cement manufacturing raw material is heated to about _____________
a) 650-900 °C
b) 900-1300 °C
c) 1300-1450 °C
d) 900-1050 °C
Explanation: At 1300-1450 °C partial (20–30%) melting takes place, and belite reacts with calcium oxide to form alite.