Abstract
Giorgiosite is a relatively unknown hydrated magnesium carbonate (HMC) without a clear understanding of its characteristics and synthesis pathway. The phase has a nano-wire morphology with high surface area, and hence, attracts immediate interests for various applications including as early-strength-giving phase in HMC-based binder. However, there had been no clear and successful pathway in the past to synthesize the phase. The present work addresses this research gap and reports an effective protocol to obtain giorgiosite in high purity. We found that giorgiosite can be synthesized via the conversion of pure nesquehonite [MgCO3·3H2O] in a 1M Mg-acetate solution at 50 °C. In contrast, nesquehonite converted to dypingite [Mg5(CO3)4(OH)2·5H2O] in the absence of acetate. Here, the characteristics of giorgiosite as determined by XRD, TGA/FTIR, SEM, and Raman spectroscopy are reported. The better understanding of the characteristics of giorgiosite will contribute to the development of HMC-based binders, which have the potential to be a carbon-negative construction material. Further work is needed to shed light on the conversion pathway in the presence of organic ligand (e.g., acetate) and to determine the thermodynamic properties of giorgiosite.Abstract
Giorgiosite is a relatively unknown hydrated magnesium carbonate (HMC) without a clear understanding of its characteristics and synthesis pathway. The phase has a nano-wire morphology with high surface area, and hence, attracts immediate interests for various applications including as early-strength-giving phase in HMC-based binder. However, there had been no clear and successful pathway in the past to synthesize the phase. The present work addresses this research gap and reports an effective protocol to obtain giorgiosite in high purity. We found that giorgiosite can be synthesized via the conversion of pure nesquehonite [MgCO3·3H2O] in a 1M Mg-acetate solution at 50 °C. In contrast, nesquehonite converted to dypingite [Mg5(CO3)4(OH)2·5H2O] in the absence of acetate. Here, the characteristics of giorgiosite as determined by XRD, TGA/FTIR, SEM, and Raman spectroscopy are reported. The better understanding of the characteristics of giorgiosite will contribute to the development of HMC-based binders, which have the potential to be a carbon-negative construction material. Further work is needed to shed light on the conversion pathway in the presence of organic ligand (e.g., acetate) and to determine the thermodynamic properties of giorgiosite
