SSC JE Civil Engineering 2018 Set 5 Solved Paper

Cement kiln have temperature 1450°C
→ 70° to 110°C: Free water is evaporate
→ 400 to 600°C: Clay like mineral are decomposed into their constituent oxides principally SiO${}_2$and $\mathit{A}{\mathit{l}}_2{\mathit{O}}_3$ . Dolomite $(\mathit{C}\mathit{a}\mathit{H}\mathit{g}{\left(\mathit{C}{\mathit{O}}_3\right)}_2$) decomposes to calcium carbonats $\mathit{C}\mathit{a}\mathit{C}{\mathit{O}}_3$ , HgO and $\mathit{C}{\mathit{O}}_2$ ,
→ 650°C to 900°C: $\mathit{C}\mathit{a}\mathit{C}{\mathit{O}}_3$ reacts with $\mathit{S}\mathit{i}{\mathit{O}}_2$ to form belite $(\mathit{C}{\mathit{a}}_2\mathit{S}\mathit{i}{\mathit{O}}_4$ ) (also known as ${\mathit{C}}_2\mathit{S})$
→ 900°C to 1050°C: Remaining $\mathit{C}\mathit{a}\mathit{C}{\mathit{O}}_3$ decomposes to CaO and $\mathit{C}{\mathit{O}}_2$
→1300°C to 1450°C: Partial (20 - 30%) melting takes place, and belite reacts with CaO to form Alite $(\mathit{C}{\mathit{a}}_3\mathit{O}.\mathit{S}\mathit{i}{\mathit{O}}_4$ ) (${\mathit{C}}_3\mathit{S})$