Pilot-Scale Operation of a Concrete Sludge Recycling Plant and Simultaneous Production of Calcium Carbonate

• Published in: Chemical engineering communications Vol. 204; no. 1; pp. 79 - 85
• Main Authors: Iizuka, Atsushi, Sasaki, Takeshi, Honma, Masato, Yoshida, Hiroyuki, Hayakawa, Yasuyuki, Yanagisawa, Yukio, Yamasaki, Akihiro
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 02.01.2017; Taylor & Francis Ltd
• Subjects: Calcium; Calcium carbonate; Carbon capture and storage; Carbon dioxide; Concrete construction; Concrete sludge; Concretes; Mineral carbonation; Power plants; Sludge; utilization; Waste treatment
• ISSN: 0098-6445; 1563-5201
• DOI: 10.1080/00986445.2016.1235564

A pilot-scale plant to treat concrete sludge and produce calcium carbonate (CaCO 3 ) and an environmental purification agent (phosphorus adsorbent derived from concrete sludge, PAdeCS®) was designed, constructed, and operated. Concrete sludge from a concrete pile and pole production plant, boiler gas containing CO 2 , and groundwater were used in the plant. The process involved calcium extraction from concrete sludge into water, followed by reaction of the calcium with CO 2 to produce crystalline CaCO 3 . The pilot-scale plant was operated for 1 week, and the mass flows, conversion of CO 2 to CaCO 3 , and net CO 2 emissions of the process were estimated. High-purity CaCO 3 (>97%) suitable for industrial use was obtained. Based on the power consumption of the process and the amount of CO 2 sequestered into CaCO 3 , a net reduction in CO 2 emissions can be achieved using this process. The produced PAdeCS can be used as an inexpensive substitute for calcium series environmental purification agents.