Carbon dioxide sequestration by industrial wastes through mineral carbonation: Current status and perspectives

Abstract

Mineral carbonation using natural minerals or industrial wastes is a safe and promising strategy for CO₂ sequestration. Application of industrial wastes for this purpose has significant ecological and environmental value, which is one of the key green technologies in the global carbon mitigation portfolio. This review summarizes the current research status of CO₂ mineralization by industrial wastes. It surveys the mechanisms and capacities of CO₂ mineralization using different industrial wastes (mainly steel slags, blast furnace slags, coal fly ash, waste gypsum, phosphogypsum and red mud), evaluates the influence of carbonation pathways and process parameters on the CO₂ sequestration capacity of industrial wastes, and analyzes the current industrial application status of CO₂ sequestration using industrial wastes. Direct aqueous carbonation and indirect carbonation are the two most studied and most promising mineralization routes. The leaching-mineralization cycle process has great potential for industrial application, especially for the treatment of coal fly ash, steel slag and other wastes containing calcium oxide, owing to the stable cycle performance of the absorbers. Researches pay more attention to CO₂ mineralization by steel slag compared to other wastes, and the capacity of CO₂ mineralization varies greatly for different wastes. Several reports already reported carbonation effectiveness up to 100%. A CO₂ sequestration capacity reached 536 g/kg for steel slag and 361 g/kg of blast furnace slag, revealing superior properties of these materials. CO₂ sequestration using industrial wastes benefits CO₂ emission reduction and comprehensive utilization of industrial wastes. To overcome the problem of the high energy consumption for regeneration of absorbent, a novel integrated CO₂ absorption-mineralization process is currently widely studied. A possibility of co-production of value-added products - like different types of zeolite or lithium orthosilicate based adsorbents was highlighted, improving the economic balance of the overall process. More studies on pilot scale should be performed, to fully confirm the feasibility of developed technologies. Application of these developments at real case scenario is still faced with significant issues, including low carbonation efficiency, poor product quality, high process cost, and insufficient mass and heat transfer. In future studies, it is necessary to investigate the mechanisms of CO₂ sequestration, the optimization of process parameters, the exploration of ways to accelerate carbonation, and the generation of value-added products or effective by-product utilization.