Lei Liu , Guangfeng Ou , Lei Xu , Naoki Ogiwara , Sayaka Uchida , Huaming Yang , Yuya Sakai
{"title":"利用碱处理和碳化法同时从废弃混凝土粉末中制备高纯度碳酸钙和无定形纳米富硅凝胶。","authors":"Lei Liu , Guangfeng Ou , Lei Xu , Naoki Ogiwara , Sayaka Uchida , Huaming Yang , Yuya Sakai","doi":"10.1016/j.jenvman.2024.123319","DOIUrl":null,"url":null,"abstract":"<div><div>Simultaneous productions of high-purity CaCO<sub>3</sub> (calcium carbonate) and amorphous nanosized SiO<sub>2</sub>-rich (silica-rich) gel from waste concrete powder remain quite challenging, and thus the high-value added utilization of waste concrete powder is significantly limited. A novel technology involving a combination of alkaline treatment and carbonation, has been proposed for the greatly enhanced utilization of waste concrete powder. Through alkaline treatment, CaCO<sub>3</sub> and SiO<sub>2</sub>-rich gel formed during carbonation of concrete powder were transformed into Ca(OH)<sub>2</sub> (calcium hydroxide) and Na<sub>2</sub>SiO<sub>3</sub> (sodium metasilicate), respectively. Subsequently, Ca(OH)<sub>2</sub> and Na<sub>2</sub>SiO<sub>3</sub> were separated. As a result, CaCO<sub>3</sub> with a high purity of 98.54% and amorphous nanosized SiO<sub>2</sub>-rich gel were obtained via carbonation, and the recovery ratio of CaCO<sub>3</sub> was 81.46%. Furthermore, the concrete powder exhibited a high CO<sub>2</sub> (carbon dioxide) uptake efficiency of 0.24g CO<sub>2</sub>/g. 30.31 Mt CaCO<sub>3</sub> and 2.77 Mt SiO<sub>2</sub>-rich gel productions as well as 38.54 Mt CO<sub>2</sub> emission reduction could be realized via recycling a quarter of annually generated waste concrete powder worldwide.</div></div>","PeriodicalId":356,"journal":{"name":"Journal of Environmental Management","volume":"372 ","pages":"Article 123319"},"PeriodicalIF":8.0000,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Simultaneous productions of high-purity calcium carbonate and amorphous nanosized silica-rich gel from waste concrete powder by alkaline treatment and carbonation\",\"authors\":\"Lei Liu , Guangfeng Ou , Lei Xu , Naoki Ogiwara , Sayaka Uchida , Huaming Yang , Yuya Sakai\",\"doi\":\"10.1016/j.jenvman.2024.123319\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Simultaneous productions of high-purity CaCO<sub>3</sub> (calcium carbonate) and amorphous nanosized SiO<sub>2</sub>-rich (silica-rich) gel from waste concrete powder remain quite challenging, and thus the high-value added utilization of waste concrete powder is significantly limited. A novel technology involving a combination of alkaline treatment and carbonation, has been proposed for the greatly enhanced utilization of waste concrete powder. Through alkaline treatment, CaCO<sub>3</sub> and SiO<sub>2</sub>-rich gel formed during carbonation of concrete powder were transformed into Ca(OH)<sub>2</sub> (calcium hydroxide) and Na<sub>2</sub>SiO<sub>3</sub> (sodium metasilicate), respectively. Subsequently, Ca(OH)<sub>2</sub> and Na<sub>2</sub>SiO<sub>3</sub> were separated. As a result, CaCO<sub>3</sub> with a high purity of 98.54% and amorphous nanosized SiO<sub>2</sub>-rich gel were obtained via carbonation, and the recovery ratio of CaCO<sub>3</sub> was 81.46%. Furthermore, the concrete powder exhibited a high CO<sub>2</sub> (carbon dioxide) uptake efficiency of 0.24g CO<sub>2</sub>/g. 30.31 Mt CaCO<sub>3</sub> and 2.77 Mt SiO<sub>2</sub>-rich gel productions as well as 38.54 Mt CO<sub>2</sub> emission reduction could be realized via recycling a quarter of annually generated waste concrete powder worldwide.</div></div>\",\"PeriodicalId\":356,\"journal\":{\"name\":\"Journal of Environmental Management\",\"volume\":\"372 \",\"pages\":\"Article 123319\"},\"PeriodicalIF\":8.0000,\"publicationDate\":\"2024-11-16\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Environmental Management\",\"FirstCategoryId\":\"93\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S030147972403305X\",\"RegionNum\":2,\"RegionCategory\":\"环境科学与生态学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ENVIRONMENTAL SCIENCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Environmental Management","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S030147972403305X","RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
Simultaneous productions of high-purity calcium carbonate and amorphous nanosized silica-rich gel from waste concrete powder by alkaline treatment and carbonation
Simultaneous productions of high-purity CaCO3 (calcium carbonate) and amorphous nanosized SiO2-rich (silica-rich) gel from waste concrete powder remain quite challenging, and thus the high-value added utilization of waste concrete powder is significantly limited. A novel technology involving a combination of alkaline treatment and carbonation, has been proposed for the greatly enhanced utilization of waste concrete powder. Through alkaline treatment, CaCO3 and SiO2-rich gel formed during carbonation of concrete powder were transformed into Ca(OH)2 (calcium hydroxide) and Na2SiO3 (sodium metasilicate), respectively. Subsequently, Ca(OH)2 and Na2SiO3 were separated. As a result, CaCO3 with a high purity of 98.54% and amorphous nanosized SiO2-rich gel were obtained via carbonation, and the recovery ratio of CaCO3 was 81.46%. Furthermore, the concrete powder exhibited a high CO2 (carbon dioxide) uptake efficiency of 0.24g CO2/g. 30.31 Mt CaCO3 and 2.77 Mt SiO2-rich gel productions as well as 38.54 Mt CO2 emission reduction could be realized via recycling a quarter of annually generated waste concrete powder worldwide.
期刊介绍:
The Journal of Environmental Management is a journal for the publication of peer reviewed, original research for all aspects of management and the managed use of the environment, both natural and man-made.Critical review articles are also welcome; submission of these is strongly encouraged.