(716b) An Analysis of Extraction Mechanism and the Role of Grinding in Carbon Dioxide Mineralization Processes

In order to effectively extract the alkaline-earth metals contained within raw minerals for carbon dioxide mineralization, the source minerals must be activated. Activation of these minerals almost always involves comminution to small particle sizes, which increase the reactive surface area and thus the availability of these alkaline-earth metals for extraction and reaction. However, the energy use for the comminution step can be a concern when intensive grinding is employed. In this paper, we attempt to analyze the role of grinding and set it against a broader context. The results of our analysis indicates that 1) grinding is not a major energy consumer, especially when compared with other unit operations typically involved in carbon dioxide mineralization processes, and 2) intensive grinding is often not required, as the amount of alkaline-earth metals extracted does not increase proportionally with the increased grinding. The first conclusion suggests that research should be focused on other more energy intensive aspects of the process design, and the second conclusion suggests that capital costs for the comminution step can be reduced as intensive grinding gives diminishing returns beyond a certain particle size limit. Three scenarios were designed to predict the extraction physical mechanism. A model is suggested here to present the mechanism of the solid-liquid extraction for mineral dissolution. The crackling core model described by the cracks on the surface of the mineral solid pellet and acid penetrate into interior area. The shrinking of the original core occurred with shaping a grainy structure behind. It was observed that each grain reacts with acid by shrinking core model.