{"title":"将 AOD 熔渣转化为具有显著二氧化碳封存功能的高活性矿物掺合料:水化行为、微观结构演变和二氧化碳足迹","authors":"Liwu Mo , Peng Liu , Yahui Gu , Jiahua Kuang","doi":"10.1016/j.cemconcomp.2024.105863","DOIUrl":null,"url":null,"abstract":"<div><div>The use of argon oxygen decarbonization slag (AODS) is restricted due to its volume unsoundness and low hydration reactivity. In this study, the feasibility of transforming AODS toward a highly reactive mineral admixture with appreciable CO<sub>2</sub> sequestration was investigated, the hydration behavior, evolution of the compositions and microstructures of AODS with carbonation time were systematically studied, and CO<sub>2</sub> footprint of carbonated AODS was elucidated. Results indicated that γ-C<sub>2</sub>S in AODS could quickly react with CO<sub>2</sub> to form CaCO<sub>3</sub>. MgO and bredigite dissolved significantly when the pH value of the slurry dropped to 7.0, leading to a significant increase in the Mg<sup>2+</sup> concentration of the slurry, and promoting the conversion of calcite to monohydrocalcite. However, due to the lower Ca/Si and Ca/Mg ratios, calcium silicate (CS) and akermanite exhibited extremely low carbonation reactivity. As the carbonation time increased, the particle size of CaCO<sub>3</sub> gradually increased, from approximately 150 nm at 5min to approximately 400 nm at 20min, [SiO<sub>4</sub>] gradually transited from the Q<sup>0</sup>, Q<sup>1</sup> and Q<sup>2</sup> structures to the Q<sup>3</sup> and Q<sup>4</sup> structures, ultimately forming a large amount of amorphous SiO<sub>2</sub> gel, which led to an obvious increase in specific surface area of AODS. The compressive strength of cement mortar mixed with 20 wt% carbonated AODS (CAODS) was increased by 25.8 % compared with that of the mortar incorporating AODS. The CO<sub>2</sub> sequestration capacity of AODS can reach approximately 200 kg/t, and 193.4 kg CO<sub>2</sub> can be cut when 1 ton of CAODS-based composite cement with excellent cementitious properties is produced.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"156 ","pages":"Article 105863"},"PeriodicalIF":10.8000,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Transforming AOD slag toward a highly reactive mineral admixture with appreciable CO2 sequestration: Hydration behavior, microstructure evolution, and CO2 footprint\",\"authors\":\"Liwu Mo , Peng Liu , Yahui Gu , Jiahua Kuang\",\"doi\":\"10.1016/j.cemconcomp.2024.105863\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The use of argon oxygen decarbonization slag (AODS) is restricted due to its volume unsoundness and low hydration reactivity. In this study, the feasibility of transforming AODS toward a highly reactive mineral admixture with appreciable CO<sub>2</sub> sequestration was investigated, the hydration behavior, evolution of the compositions and microstructures of AODS with carbonation time were systematically studied, and CO<sub>2</sub> footprint of carbonated AODS was elucidated. Results indicated that γ-C<sub>2</sub>S in AODS could quickly react with CO<sub>2</sub> to form CaCO<sub>3</sub>. MgO and bredigite dissolved significantly when the pH value of the slurry dropped to 7.0, leading to a significant increase in the Mg<sup>2+</sup> concentration of the slurry, and promoting the conversion of calcite to monohydrocalcite. However, due to the lower Ca/Si and Ca/Mg ratios, calcium silicate (CS) and akermanite exhibited extremely low carbonation reactivity. As the carbonation time increased, the particle size of CaCO<sub>3</sub> gradually increased, from approximately 150 nm at 5min to approximately 400 nm at 20min, [SiO<sub>4</sub>] gradually transited from the Q<sup>0</sup>, Q<sup>1</sup> and Q<sup>2</sup> structures to the Q<sup>3</sup> and Q<sup>4</sup> structures, ultimately forming a large amount of amorphous SiO<sub>2</sub> gel, which led to an obvious increase in specific surface area of AODS. The compressive strength of cement mortar mixed with 20 wt% carbonated AODS (CAODS) was increased by 25.8 % compared with that of the mortar incorporating AODS. The CO<sub>2</sub> sequestration capacity of AODS can reach approximately 200 kg/t, and 193.4 kg CO<sub>2</sub> can be cut when 1 ton of CAODS-based composite cement with excellent cementitious properties is produced.</div></div>\",\"PeriodicalId\":9865,\"journal\":{\"name\":\"Cement & concrete composites\",\"volume\":\"156 \",\"pages\":\"Article 105863\"},\"PeriodicalIF\":10.8000,\"publicationDate\":\"2024-11-21\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Cement & concrete composites\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0958946524004360\",\"RegionNum\":1,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CONSTRUCTION & BUILDING TECHNOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cement & concrete composites","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0958946524004360","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CONSTRUCTION & BUILDING TECHNOLOGY","Score":null,"Total":0}
Transforming AOD slag toward a highly reactive mineral admixture with appreciable CO2 sequestration: Hydration behavior, microstructure evolution, and CO2 footprint
The use of argon oxygen decarbonization slag (AODS) is restricted due to its volume unsoundness and low hydration reactivity. In this study, the feasibility of transforming AODS toward a highly reactive mineral admixture with appreciable CO2 sequestration was investigated, the hydration behavior, evolution of the compositions and microstructures of AODS with carbonation time were systematically studied, and CO2 footprint of carbonated AODS was elucidated. Results indicated that γ-C2S in AODS could quickly react with CO2 to form CaCO3. MgO and bredigite dissolved significantly when the pH value of the slurry dropped to 7.0, leading to a significant increase in the Mg2+ concentration of the slurry, and promoting the conversion of calcite to monohydrocalcite. However, due to the lower Ca/Si and Ca/Mg ratios, calcium silicate (CS) and akermanite exhibited extremely low carbonation reactivity. As the carbonation time increased, the particle size of CaCO3 gradually increased, from approximately 150 nm at 5min to approximately 400 nm at 20min, [SiO4] gradually transited from the Q0, Q1 and Q2 structures to the Q3 and Q4 structures, ultimately forming a large amount of amorphous SiO2 gel, which led to an obvious increase in specific surface area of AODS. The compressive strength of cement mortar mixed with 20 wt% carbonated AODS (CAODS) was increased by 25.8 % compared with that of the mortar incorporating AODS. The CO2 sequestration capacity of AODS can reach approximately 200 kg/t, and 193.4 kg CO2 can be cut when 1 ton of CAODS-based composite cement with excellent cementitious properties is produced.
期刊介绍:
Cement & concrete composites focuses on advancements in cement-concrete composite technology and the production, use, and performance of cement-based construction materials. It covers a wide range of materials, including fiber-reinforced composites, polymer composites, ferrocement, and those incorporating special aggregates or waste materials. Major themes include microstructure, material properties, testing, durability, mechanics, modeling, design, fabrication, and practical applications. The journal welcomes papers on structural behavior, field studies, repair and maintenance, serviceability, and sustainability. It aims to enhance understanding, provide a platform for unconventional materials, promote low-cost energy-saving materials, and bridge the gap between materials science, engineering, and construction. Special issues on emerging topics are also published to encourage collaboration between materials scientists, engineers, designers, and fabricators.