Dolomite-based binders manufactured using concentrated solar energy in a fluidised bed reactor. (15th January 2022)

• Record Type: Journal Article
• Authors: Marroccoli, Milena; Ibris, Neluta; Telesca, Antonio; Tregambi, Claudio; Solimene, Roberto; Di Lauro, Francesca; Ruiz de Ballesteros, Odda; Salatino, Piero; Montagnaro, Fabio
• Is Part Of: Solar energy. Volume 232(2022)
• Page Start: 471
• Page End: 482
• Publication Date: 2022-01-15
• Subjects: Concentrated solar thermal energy -- Directly irradiated fluidised bed reactor -- Dolomite-based binders -- Hydration -- Low-CO2 cements -- Solar materials production; A Anhydrite (CaSO4) signal in XRD (AMCSD code 0020857) -- B Brucite (Mg(OH)2) signal in XRD (AMCSD code 0002433) -- BFS Blast furnace slag -- C Calcite (CaCO3) signal in XRD (AMCSD code 0000098)/DT-TG -- CD Calcined dolomite -- CH Ca(OH)2 signal in DT-TG -- CSH Calcium silicate hydrates signal in DT-TG -- CSP Concentrating solar power -- D Dolomite (CaMg(CO3)2) signal in XRD (AMCSD code 0000906) -- DEP Dehydration endothermal peak -- DT-TG Differential thermal-thermogravimetric -- FA Fly ash -- FB Fluidised bed -- GGBFS Ground granulated blast furnace slag -- Gh Hydrated gehlenite (2CaO·Al2O3·SiO2·8H2O) signal in DT-TG -- He Hematite (Fe2O3) signal in XRD (AMCSD code 0000143) -- HSD/BFS3 Slaked dolomite and 30% by mass blast furnace slag hydrated sample -- HSD/BFS5 Slaked dolomite and 50% by mass blast furnace slag hydrated sample -- HSD/FA3 Slaked dolomite and 30% by mass fly ash hydrated sample -- HSD/FA5 Slaked dolomite and 50% by mass fly ash hydrated sample -- Ht Hydrotalcite (Mg6Al2(CO3)(OH)16·4H2O) signal in XRD (AMCSD code 0014738)/DT-TG -- ID Internal diameter -- IRC Infrared camera -- L Lime (CaO) signal in XRD (AMCSD code 0008328) -- M Mullite (3Al2O3·2SiO2) signal in XRD (AMCSD code 0001059) -- MBC MgO-based cements -- MC MgCO3 signal in DT-TG -- MH Mg(OH)2 signal in DT-TG -- P Portlandite (Ca(OH)2) signal in XRD (AMCSD code 0008415) -- PC Portland cement -- PC-Cli Portland cement clinker -- Pe Periclase (MgO) signal in XRD (AMCSD code 0020752) -- Q Quartz (SiO2) signal in XRD (AMCSD code 0000789) -- RK Rotary kiln -- S Siderite (FeCO3) signal in XRD (AMCSD code 0017592) -- SCM Supplementary cementitious materials -- SD Slaked dolomite -- SD/BFS3 Mixture of slaked dolomite and 30% by mass blast furnace slag -- SD/BFS5 Mixture of slaked dolomite and 50% by mass blast furnace slag -- SD/FA3 Mixture of slaked dolomite and 30% by mass fly ash -- SD/FA5 Mixture of slaked dolomite and 50% by mass fly ash -- TWL Total weight loss -- XRD X-ray diffraction -- XRF X-ray fluorescence; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2022.01.007
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: Low-CO2 dolomite-based binders were synthesized. Light burned dolomite was manufactured from solar driven calcination in fluidised bed. Slaked dolomite was mixed with blast furnace slag or coal fly ash samples. Formation of hydrotalcite and calcium silicate hydrates was demonstrated. The proposed approach reduces the carbon footprint of the cement industry. Abstract: Dolomite-based binders are characterised by interesting technical and environmental features. For their synthesis, sources of both CaO and MgO are required. The idea developed in this work is to couple the synthesis of dolomite-based binders, starting from a natural dolomite, through the concept of concentrated solar energy (needed to drive the endothermal dolomite calcination process) in fluidised bed reactors. To this end, a fluidised bed system, where the concentrated solar radiation is mimicked by the use of Xe-lamps (short-arc), has been set up and operated. Natural dolomite (sieved in the 420–590 μm size range) was calcined at a nominal temperature of 850 °C, and bed temperature profiles during solar-driven calcination were investigated. Then, four binders were prepared by mixing slaked dolomite (obtained from the hydration of solar calcined dolomite) with either blast furnace slag or coal fly ash as supplementary cementitious materials. The binders were hydrated for curing times ranging from 7 to 56 days. X-ray fluorescence, X-ray diffraction and combined differential thermal and thermogravimetric analyses were employed as characterisation techniques both to analyse the chemical composition of starting materials and to investigate the evolution of the hydration in the four systems.