If clinkers cool down slowly after the clinkering zone due to the falure of the cooling system, what mineral will be the largest content in these clinkers? 

Select the correct answer from the list (2 marks)

NOTE: Questions 16-19 are under the one Category of Cement Production.

There are four different zones in a burning kiln (before cooling): 

• Dehydration zone
• Calcination zone
• Solid-state reaction zone
• Clinkering zone.

After the rapid cooling process, this process creates the four main cement minerals: 

• C3S
• C2S
• C4AF
• C3A

Which zone is involved in the largest CO2 emission during the cement clinkering production? Select the correct answer from the list (2 marks)

Shrinkage only occurs after the concrete is fully hardened.

CaO, Fe2O3, SiO2 and Al2O3 are four major chemical oxides.