Modified Bauxite Residue as an Alternative Supplementary Cementitious

Modified Bauxite Residue as an Alternative Supplementary Cementitious Material Pithchai Sivakumar KU Leuven (Belgium)

Current scenario Ø Cement industry = 8 to 10 % of global CO 2 emission, 4 to 5 billions tonnes of cement production Ø Alumina industry = 150 to 180 millions tonnes of bauxite residue Possible alternative Can we use bauxite residue in cement industry? Yes! As a SCM after modification 2 Faculty of Engineering Science, Department of Materials Engineering

Experimental procedure 81. 5% BR 9. 25% Si. O 2 9. 25% B 2 O 3 Thermodynamic calculation Ø 64 wt% liquid Ø 36 wt% hematite 1 h 1200 °C Quenching BR Slag mortar 40% (BR Slag) + 60% (OPC)+ Sand + Water “BR Slag” 3 Faculty of Engineering Science, Department of Materials Engineering

Results and discussion Characterisation of BR slag “BR Slag” Amorphous (Ti, Al) Hematite Component Al 2 O 3 Si. O 2 B 2 O 3 Ca. O Fe 2 O 3 Ti. O 2 Na 2 O wt% 28 26 14 11 8 6 3 4 Composition of amorphous phase (mass balance) Faculty of Engineering Science, Department of Materials Engineering

Compressive strength “BR Slag mortar” Conclusion Ø Use of B 2 O 3 and Si. O 2 as fluxing admixtures in a thermal process. Ø BR slag mortar: compressive strength = 66 MPa after 28 d, exceeding the OPC. Ø Process contributes to minimising the volume of disposed BR. 5 Faculty of Engineering Science, Department of Materials Engineering

Thank you. . .