CO2 sequestration characteristics in the cementitious material based on gangue backfilling mining method

The increasing anthropogenic CO2 emission and global warming has challenged the China and other countries to seek new and better ways to meet the world's increasing need for energy while reducing greenhouse gas emissions. The overall proposition of this research is to develop a brand-new CO2 physical and chemical sequestration method by using solid waste of coal mining and cementitious material which are widely used for goaf backfilling in coal mining. This research developed a new testing system (constant temperature pressurized reaction chamber (CTPRC)) to study the effects of different initial parameters on mineral carbonation such as different initial water-binder ratio, initial sample porosity and initial carbon dioxide pressure. The experimental results show that the CO2 consumption ratio is 15%, 10% and 7% higher with relatively high initial water-binder ratio, initial sample porosity and initial CO2 pressure within 48 h. In addition, some physical and chemical evidence was found through the electron microscope scanning and XRD test to further explain the above test results. This proposed research will provide critical parameters for optimizing CO2 sequestration capacity in this cementitious backfilling material with forming agent.