Experimental investigation of enhanced carbonation by solvent extraction for indirect CO₂mineral sequestration

Abstract

An indirect CO 2 mineral sequestration involving two separated steps with acetic acid as a recycling medium provides a promising method for CO 2 sequestration as well as the minimum CO 2 emission for calcium carbonate production. In such an indirect route, the calcium carbonate production in the second gas-liquid reactive crystallization step has been challenged by low carbonation effi ciency. This paper describes signifi cant enhancement of the second step by coupling reactive crystallization and solvent extraction with the introduction of the organic solvent, tributyl phosphate (TBP), to the process. Based on the reaction mechanism of this enhanced carbonation process, many infl uencing factors including stirring speed, phase ratio, reaction time, reaction temperature, CO 2 partial pressure, and the composition of the initial aqueous solution, were studied. Given the operating conditions of 60 min reaction time, 500 rpm stirring speed, organic-to-aqueous phase volume ratio of 1, 80 °C reaction temperature, 4.0 MPa CO 2 partial pressure, and initial pH of 7, the obtained crystallization conversion in the second step was found to increase from 20% to above 50%, with the incorporation of TBP and the addition of magnesium acetate.

Carbon Capture and Utilization Update

“…Accelerating the reaction kinetics through advanced materials is one way to improve the efficiency of the process . Indirect mineral carbonation is considered to be the most useful process, and it has the potential to be scaled up in the near future . A near‐complete in situ CO 2 mineralization process in Basaltic rocks has recently been achieved within a two‐year timeframe …”

Purification of slag-derived leachate and selective carbonation for high-quality precipitated calcium carbonate synthesis

“…Still, after carbonation of the leachates, the calcium concentration of the post-carbonation precipitates remained in the range of 69 -90 wt%, and different mineralogical phases were also present. Based on these past studies, it appears that improvement of PCC purity may only be reached by removing the main impurities prior to the carbonation step, for example by selective precipitation [9].…”

Carbon Dioxide Capture, Utilization, and Sequestration: Current Status, Challenges, and Future Prospects for Global Decarbonization

“…Despite these challenges, ongoing research is exploring ways to optimize the mineral storage process and reduce the associated costs. For example, researchers are exploring the use of waste materials, such as fly ash from coal-fired power plants, as a source of minerals for the mineral storage process. − Other research is focused on developing more efficient mineral processing techniques, such as using solvents to accelerate the reaction between CO 2 and minerals. , …”

“…273−277 Other research is focused on developing more efficient mineral processing techniques, such as using solvents to accelerate the reaction between CO 2 and minerals. 278,279 Overall, mineral storage has the potential to be a promising method for long-term storage of CO 2 emissions, but further research and development are needed to overcome the current technical and economic challenges.…”