Carbstone: Sustainable Valorisation Technology for Fine Grained Steel Slags and CO2*


Volume 2, Issue 2, Pages 75-79


A technology was developed to produce high strength building materials by treating slags with CO2 at elevated pressure (20 bar) and temperature (140 °C) without addition of binders. The carbonated materials can compete with concrete products (C35/C45) and have excellent environmental and technical properties. The materials have the additional advantage of sequestering 180 – 200 g CO2/kg slag. The process makes use of a unique combination of existing technologies commonly used in the construction industry. Building of a pilot installation for treatment of 10 000 t of slag per year is planned for the near future.


Carbonation, steel slag, CO2, recycling



[1] Nexhip, C; Davidson, R; Norgate, T; Sanetsis, S; Washington, B: Dry granulation of slags for producing cement binder. Green Processing Conference, Fremantle 2004, WA

[2] Bertos, M.F.; Simons, S.J.R.; Hills, C.D.; Carey, P.J.: A review of accelerated carbonation technology in the treatment of cement-based materials and sequestration of CO2. J. of Hazardous Materials 112 (2004) 193–205

[3] Nguyen, E; Lecomte, I; van Mechelen, D: New sustainable valorisation routes for fine grained stainless steel slags. Global Slag 2009, Brussels,  Conference Proceedings 

[4] Gunning, P.J.; Hills, C.D.; Carey, P.J.: Production of lightweight aggregate from industrial waste and carbon dioxide. Waste Management  29 (2009) 2722–2728

[5] Johnson, D.C.; Macload, C.L.; Carey, P.J.: Solidi-fication of stainless steel slag by accelerated carbonation. Environmental Technology 24 (2003) 671–678

[7] Nielsen, P.; Quaghebeur, M.; Laenen, B.; Kemps, R.; van Bommel, P: The use of MSWI bottom ash as aggregate in concrete limitations and possible solutions. WASCON 2009, Lyon, Conference Proceedings

[8] Quaghebeur, M.; Nielsen, P.; Laenen, B.: Accelerated carbonation to improve quality of recycling methods: a study of the real time kinetics. WASCON 2009, Lyon, Conference Proceedings (2009); WO2009/133120 Production of a mainly carbonate bonded article by carbonation of alkaline materials. JP2000-247711 Production of Artificial Stone


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