ORALS

SESSION: NonferrousTuePM1-R5	8th Intl. Symp. on Sustainable Non-ferrous Smelting & Hydro/Electrochemical Processing
Tue. 29 Nov. 2022 / Room: Arcadia 2
Session Chairs: TBA Session Monitor: TBA

14:50: [NonferrousTuePM107] OS
Calcined Clay Blended Cements For Sustainable Cement Production
Ran Li¹ ; Marlene Schmid¹ ; Aleksandar Jaglicic¹ ; Tongbo Sui² ; Johann Plank³ ; ¹Technical University of Munich (TUM), Garching, Germany; ²Sinoma Int’l & Sinoma Research Institute, Chaoyang District, Beijing, China; ³Technical University of Munich, Garching, Germany;
Paper Id: 141 [Abstract]

This paper presents that the CO₂ footprint of cement can be reduced significantly by blending Portland cement clinker with thermally activated (calcined) clays (CCs). Investigations on pure meta phases obtained via calcination of kaolin, montmorillonite, illite and muscovite reveal that they increase water demand and decrease workability of the cement. The effect depends on fineness and internal porosity of the calcined clay and the chemical composition of the native clay, with illite and kaolin behaving much less favorably than montmorillonite or muscovite. A comparison of three industrial calcined samples of mixed layer clays originating from natural clay deposits in Germany, India and China confirmed the increased water demand of composite cements holding up to 40 wt. % of these calcined clays. The increase in water demand correlates well with the amorphous part and the content of meta kaolin in the calcined mixed layer clay. For one sample holding ~ 50 % meta kaolin, an increase in superplasticizer dosage of ~ 400 % as compared to neat OPC was recorded. Whereas, a high content of meta kaolin proved to be favorable with respect to early strength development as a result of its high pozzolanic reactivity. It can be concluded that calcined clays offer the potential of significant CO₂ reduction in cement manufacture, however this comes at the price of higher admixture dosages for superplasticizers. Still, a substantial savings in CO₂ emission can be realized, and the cement industry can progress into an era of more eco-friendly binders.

References:
K. Scrivener, F. Martirena, S. Bishnoi, S. Maity, Calcined clay limestone cements (LC3), Cem. Concr. Res. 114 (2018) 49–56.\nS. Ferreiro, D. Herfort, J.S. Damtoft, Effect of raw clay type, fineness, water-tocement ratio and fly ash addition on workability and strength performance of calcined clay – Limestone Portland cements, Cem. Concr. Res. 101 (2017) 1–12.\nT. R. Muzenda, P. Hou, S. Kawashima, T. Sui, X. Cheng, The role of limestone and calcined clay on the rheological properties of LC3, Cem. Concr. Compos. 107 (2020), 103516.\nR. Fernandez, F. Martirena, K.L. Scrivener, The origin of the pozzolanic activity of calcined clay minerals: A comparison between kaolinite, illite and montmorillonite, Cem. Concr. Res. 41 (2011) 113–122.\nS. Krishnan, A.C. Emmanuel, S. Bishnoi, Hydration and phase assemblage of ternary cements with calcined clay and limestone, Constr. Build. Mat. 222 (2019) 64–72.

SESSION: NonferrousTuePM2-R5	8th Intl. Symp. on Sustainable Non-ferrous Smelting & Hydro/Electrochemical Processing
Tue. 29 Nov. 2022 / Room: Arcadia 2
Session Chairs: Harn Wei Kua; Session Monitor: TBA

15:55: [NonferrousTuePM209] OS Keynote
Climate Change: Consequences for the Global Construction Industry
Johann Plank¹ ; ¹Technical University of Munich, Garching, Germany;
Paper Id: 325 [Abstract]

In Europe, construction including heating & coaling of buildings amounts for 40 % of total CO2 emission and hence presents by far the largest source of CO2 release. Globally, a similar situation exists. The paper presents current steps in the construction industry to dramatically reduce its CO2 footprint which include: 1) Migrate to low or zero carbon binders by replacing Portland cement clinker with calcined clay, slag etc. Currently, cement manufacture accounts for ~ 8 % of total global CO2 emission, just behind coal, oil and gas. 2) Capture CO2 released in cement plants and utilize for concrete hardening or dispose on CCS wells. 3) Identify CO2 stable new cements which can be used on CCS wells 4) Make highly effective thermal insulation materials mandatory on buildings. 5) Introduce concepts for mega cities to avoid unnecessary heat-up by having plants on facades, roofs, etc. to provide a sun shelter and absorb CO2. 6) Switch from heating using fossil fuel to “green” energy including solar, geothermal and wind energy. 7) Discourage the use of wood in construction, as we need more trees as a natural sink for CO2. These measures require a complete reset of our current construction processes and will result in a huge transformation of this industry.