Calcium carbonate synthesis from waste concrete for carbon dioxide capture: From laboratory to pilot scale

This research article explains the synthesis and scale-up of calcium carbonate (CaCO₃) from waste concrete as calcium-rich material by an inorganic carbonation process. The operating parameters include S/L ratio, HCl concentration, contact time, and extraction pH were investigated. The calcium hydroxide (Ca(OH)₂) was synthesized by reaction between calcium chloride (CaCl₂) and sodium hydroxide (NaOH), which induced the spontaneous reaction of CaCO₃ without additional energy consumption. The productivity of CaCO₃ was 1 kg/d in the laboratory scale experiment, and the CaCO₃ productivity was scale-up to 20 kg/d through pilot scale process by same way as the laboratory scale. The approximately 4800 g of CaCO₃ was produced and 2112 g of CO₂ was captured per each cycle operation. Consequently, considered power consumption, the estimated amount of reduced CO₂ was 465 g of CO₂ in the pilot-scale reactor per cycle and produced CaCO₃ with a purity of 99.0 %.