In a cement plant, which process is a major source of carbon dioxide emissions during cement production?

• A. Conversion of atmospheric nitrogen to ammonia in the kiln, which directly produces carbon dioxide
• B. Calcination of limestone in the kiln, where calcium carbonate decomposes into calcium oxide and carbon dioxide: $C_{1}a{C}_1{O}_3\to CaO+C{O}_2$
• C. Electrolysis of water to form hydrogen and oxygen, releasing carbon dioxide as a byproduct: $2H_{2}O\to 2H_2+O_2+C{O}_2$
• D. Condensation of water vapor from cooling exhaust gases, which generates carbon dioxide as it cools

Answer: (B)

Verified step by step guidance

1. Identify the key chemical processes involved in cement production, focusing on those that could release carbon dioxide (CO\_2).
2. Understand that calcination is the thermal decomposition of calcium carbonate (CaCO\_3) into calcium oxide (CaO) and carbon dioxide (CO\_2), which occurs in the kiln during cement production.
3. Write the chemical equation for calcination: \(\text{CaCO\_3} \rightarrow \text{CaO} + \text{CO\_2}\), showing how CO\_2 is directly produced from this reaction.
4. Recognize that other processes mentioned, such as nitrogen conversion or electrolysis of water, do not produce CO\_2 as a direct byproduct in cement production.
5. Conclude that the major source of CO\_2 emissions in cement production is the calcination of limestone (CaCO\_3) in the kiln.