1. Cement ingredients

Mineralogically speaking, cement is made essentially from four constituents:

• Lime CaO (simplified designation "C"), rather basic;

• silica SiO ₂ (simplified designation "S") ;

• Alumina Al ₂ O ₃ (simplified designation "A");

• iron oxide Fe ₂ O ₃ (simplified designation "F"), rather acidic.

• These four basic elements are not found in nature in the right state for the emergence of hydraulic binders. Indeed, lime CaO carbonates easily by absorbing carbon dioxide from...