Patent ID: 8778286

Claim:
A system for fixing carbon dioxide, the system comprising: a first reactor into which a slag is to be introduced, in which an alkali metal component is to be extracted from the slag, and from which a solution containing the extracted alkali metal component is to be discharged; a second reactor into which carbon dioxide and the solution containing the extracted alkali metal component are to be introduced and in which the alkali metal component contained in the introduced solution is to be converted to a carbonate precipitate by a carbonation reaction between the introduced carbon dioxide and the introduced solution, wherein a submerged membrane unit is provided within the second reactor to separate the carbonate precipitate; a recirculation pipeline between the first reactor and the second reactor to recirculate the solution contained in the second reactor into the first reactor; and a supply pipeline between the first reactor and the second reactor to supply the solution contained in the first reactor into the second reactor, wherein a vacuum pump is mounted on the recirculation pipeline, wherein the submerged membrane unit comprises: a plurality of hollow fiber membranes and a pair of hollow cases provided at upper and lower ends of the hollow fiber membranes, wherein the hollow cases are connected to the first reactor by the recirculation pipeline through which the solution contained in the second reactor can be recirculated to the first reactor, and wherein an air diffuser is provided in the second reactor below the submerged membrane unit for delivering gaseous carbon dioxide to the inside of the second reactor.