Abstract: A method in which carbon dioxide can be efficiently fixed, calcium carbonate that is a valuable can be efficiently produced from carbon dioxide, and a waste gypsum board can be effectively recycled without being wasted as it is by using the waste gypsum board for fixing carbon dioxide. This method includes: bringing a first solution containing an alkali metal hydroxide and gas containing carbon dioxide into contact with each other to produce a second solution containing an alkali metal salt; and bringing the second solution and a gypsum-containing material into contact with each other to produce calcium carbonate.

Abstract: Provided is a calcium carbonate generation method and system in which calcium carbonate having a high purity can be generated using a calcium-containing waste. Provided is a calcium carbonate generation method of generating calcium carbonate from a calcium-containing waste, the calcium carbonate generation method including: a calcium dissolution step of adding aqueous hydrochloric acid to a calcium-containing waste and dissolving calcium to generate an aqueous solution containing a calcium ion; a separation step of adjusting a hydrogen ion concentration index of the aqueous solution containing a calcium ion and separating a component containing at least one selected from the group consisting of Si, Al, Mg, and heavy metal from the aqueous solution; and a calcium carbonate collection step of generating calcium carbonate using an aqueous solution obtained in the separation step and an aqueous solution containing potassium carbonate and/or sodium carbonate.