Siderite-calcite (FeCO₃-CaCO₃) series cement formation by accelerated carbonation of CO₂(g)-H₂O-Fe-Ca(OH)₂ systems

Carbonation-cementation and bulk reaction mechanisms are studied in systems containing closely packed mixes of particulate Fe (0) (-10 mu m) and Ca(OH)(2) (0%, 5%, 10% and 15% w/w of Ca(OH)2) subjected to elevated CO2- pressure (1, 5, 10, and 20 barg) and temperature (30 degrees C and 60 degrees C). Solid solutions of (CaxFe1-x)CO3 series minerals are observed through shifting and broadening of XRD-reflections with variations in Ca(OH)(2) content, CO2-pressure and temperature. The product morphologies varied from rhombohedral in non-Ca(OH)(2) systems, to distorted rhombohedral (at 60 degrees C) and scalenohedral (at 30 degrees C) in the systems containing Ca(OH)(2). An X-ray diffraction-based interpolation method is developed to discern mixed and end-member carbonates for more accurate bulk phase quantification. Based on these observations, variations in cementation performances are explained. Exceptional formation of an Fe-LDH and a (Ca,Fe)-LDH has also been observed in some systems. Interestingly, these LDH phases were stable even after being exposed to ambient conditions for more than 75 days.

Jaar van publicatie:2021

Trefwoorden:A1 Journal article

Toegankelijkheid:Open