cement chemistry.pdf

1Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Fundamentals in Building Industries Cement Chemistry, Chemistry of Admixtures Prof. Dr. Andreas Gerdes Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Important mineral binders – Nowadays and in former times Lime stone (CaCO3) ?Since 5600 – 5000 b.C. ?1st traces of application: Region of the river Danube Portland cement (PC, PZ, CEM) ?Since 1824/1843 invention of J. Aspdin, improved by W. Aspdin ?Portland = natural stone from the island Portland Gypsum (CaSO4 . 2 H2O) ?Known since 9000 b.C. ?1st traces of application: Catal Huyuk Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft 0 5 10 15 20 25 30 35 40 Ze m en tp ro du kt io n in M ill io ne n To nn en [1 99 0] ? sterreich U K D eutschland Italien N orw egen Luxem burg N iederlande Spanien Schw eden Schw eiz The Portland cement – important for Economy and Society 2Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Production of Portland cement – Raw materials Raw materials for cement production: ?limestone (CaCO3) ?clay containing marl (SiO2, Al2O3, Fe2O3) ?lime containing marl (CaCO3 ,SiO2) Ideal chemical raw material composition is calculated by various parameters (e.g. KSt) KSt = Kalkstandard ~ lime standard Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Production process: Primary combustible: ?Mineral coal powder ?Brown coal powder ?Fuel oil ?Natural gas Secondary combustible : ?Waste materials (e.g. used tires) Energy demand: 3000-6000 KJ/kg Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Chemical reactions of the production of Portland cement clinker Deacidification: CaCO3 CaO + CO2(g) Thermal synthesis of the clinker components: 3 CaO + SiO2 Ca3SiO5 2 CaO + SiO2 Ca2SiO4 3 CaO + Al2O3 Ca3Al2O6 4 CaO + Al2O3 + Fe2O3 Ca4Al2Fe2O10 Stoichiometrie “elements“ and ?masses“ 3Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Portland cement clinker C4AF4 CaO.Al2O3 . Fe2O3 Ca4Al2Fe2O1