Method for manufacturing cement composition

(22) 13.12.2023

(43) 04.07.2024

(57) Provided is a method for manufacturing a cement composition in which carbon dioxide is immobilized. The method is capable of reducing the reaction time between cement and carbon dioxide and immobilizes a large amount of carbon dioxide. The method for manufacturing a cement composition uses cement, an aggregate, and water, and said method comprises: (A) a step of mixing a part of the cement and a part of the water to obtain a cement slurry in which the water-cement ratio is 250%; (B) a step of bringing the cement slurry into contact with carbonic acid gas to obtain a carbonized slurry; (C) a step of separating some water from the carbonized slurry to obtain a concentrated slurry with a liquid-solid ratio of 80% to 400%; (D) a step of mixing/kneading the concentrated slurry with the remainder of the cement to obtain a composition having a high concentration of cement; and (E) a step of mixing/kneading the composition containing a high concentration of cement with the remainder of the water to obtain the cement composition. The aggregate is supplied in step (D) or step (E).

(71) TAIHEIYO Cement Corporation, Tokyo (JP)