Mineral carbonation is a promising CO_(2) sequestration strategy that can utilize industrial wastes to convert CO_(2) into high-value CaCO_(3).This review summarizes the advancements in CO_(2) mineralization using typ...Mineral carbonation is a promising CO_(2) sequestration strategy that can utilize industrial wastes to convert CO_(2) into high-value CaCO_(3).This review summarizes the advancements in CO_(2) mineralization using typical industrial wastes to prepare ultrafine CaCO_(3).This work surveys the mechanisms of CO_(2) mineralization using these wastes and its capacities to synthesize CaCO_(3),evaluates the effects of carbonation pathways and operating parameters on the preparation of CaCO_(3),analyzes the current industrial application status and economics of this technology.Due to the large amount of impurities in solid wastes,the purity of CaCO_(3) prepared by indirect methods is greater than that prepared by direct methods.Crystalline CaCO_(3) includes three polymorphs.The polymorph of CaCO_(3) synthesized by carbonation process is determined the combined effects of various factors.These parameters essentially impact the nucleation and growth of CaCO_(3) by altering the CO_(2) supersaturation in the reaction system and the surface energy of CaCO_(3) grains.Increasing the initial pH of the solution and the CO_(2)flow rate favors the formation of vaterite,but calcite is formed under excessively high pH.Vaterite formation is favored at lower temperatures and residence time.With increased temperature and prolonged residence time,it passes through aragonite metastable phase and eventually transforms into calcite.Moreover,polymorph modifiers can decrease the surface energy of CaCO_(3) grains,facilitating the synthesis of vaterite.However,the large-scale application of this technology still faces many problems,including high costs,high energy consumption,low calcium leaching rate,low carbonation efficiency,and low product yield.Therefore,it is necessary to investigate ways to accelerate carbonation,optimize operating parameters,develop cost-effective agents,and understand the kinetics of CaCO_(3) nucleation and crystallization to obtain products with specific crystal forms.Furthermore,more studies on life cycle assessment(LCA)should be conducted to fully confirm the feasibility of the developed technologies.展开更多
Aragonite calcium carbonate whisker was prepared by thermal decomposition of Ca（HCO3）2 in aqueous solution in the presence of chloride salts. The influences of reaction temperature, time and concentrations of CaCl2,...Aragonite calcium carbonate whisker was prepared by thermal decomposition of Ca（HCO3）2 in aqueous solution in the presence of chloride salts. The influences of reaction temperature, time and concentrations of CaCl2, MgCl2 and KCl on the morphology of CaCO3 whiskers were studied. The structure characteristics of CaCO3 whiskers were analyzed by XRD and SEM. The results indicate that the optimum conditions are 80～100 ℃, 50～60 min and the suitable concentrations of Ca（HCO3）2, KCl, MgCl2, CaCl2 are 6.0 mmol/L, 14.0 mmol/L, 1.0 mmol/L, 1.5 mmol/L respectively. The purity of the whiskers is 99.53% and the average aspect ratio is 24.1.展开更多
基金support was received the Science&Technology Foundation of RIPP(PR20230092,PR20230259)the National Natural Science Foundation of China(22278419)the Key Core Technology Research(Social Development)Foundation of Suzhou(2023ss06).
文摘Mineral carbonation is a promising CO_(2) sequestration strategy that can utilize industrial wastes to convert CO_(2) into high-value CaCO_(3).This review summarizes the advancements in CO_(2) mineralization using typical industrial wastes to prepare ultrafine CaCO_(3).This work surveys the mechanisms of CO_(2) mineralization using these wastes and its capacities to synthesize CaCO_(3),evaluates the effects of carbonation pathways and operating parameters on the preparation of CaCO_(3),analyzes the current industrial application status and economics of this technology.Due to the large amount of impurities in solid wastes,the purity of CaCO_(3) prepared by indirect methods is greater than that prepared by direct methods.Crystalline CaCO_(3) includes three polymorphs.The polymorph of CaCO_(3) synthesized by carbonation process is determined the combined effects of various factors.These parameters essentially impact the nucleation and growth of CaCO_(3) by altering the CO_(2) supersaturation in the reaction system and the surface energy of CaCO_(3) grains.Increasing the initial pH of the solution and the CO_(2)flow rate favors the formation of vaterite,but calcite is formed under excessively high pH.Vaterite formation is favored at lower temperatures and residence time.With increased temperature and prolonged residence time,it passes through aragonite metastable phase and eventually transforms into calcite.Moreover,polymorph modifiers can decrease the surface energy of CaCO_(3) grains,facilitating the synthesis of vaterite.However,the large-scale application of this technology still faces many problems,including high costs,high energy consumption,low calcium leaching rate,low carbonation efficiency,and low product yield.Therefore,it is necessary to investigate ways to accelerate carbonation,optimize operating parameters,develop cost-effective agents,and understand the kinetics of CaCO_(3) nucleation and crystallization to obtain products with specific crystal forms.Furthermore,more studies on life cycle assessment(LCA)should be conducted to fully confirm the feasibility of the developed technologies.
文摘Aragonite calcium carbonate whisker was prepared by thermal decomposition of Ca（HCO3）2 in aqueous solution in the presence of chloride salts. The influences of reaction temperature, time and concentrations of CaCl2, MgCl2 and KCl on the morphology of CaCO3 whiskers were studied. The structure characteristics of CaCO3 whiskers were analyzed by XRD and SEM. The results indicate that the optimum conditions are 80～100 ℃, 50～60 min and the suitable concentrations of Ca（HCO3）2, KCl, MgCl2, CaCl2 are 6.0 mmol/L, 14.0 mmol/L, 1.0 mmol/L, 1.5 mmol/L respectively. The purity of the whiskers is 99.53% and the average aspect ratio is 24.1.
