5.1.5. CAC + CO<sup>2</sup> Generation

The search with the keywords, calcium aluminate cement and CO<sup>2</sup> generation (CAC + CO<sup>2</sup> generation) in the Scopus database returned five results. The number of documents produced per year is presented in Figure 8e. This reveals almost no production in the last 9 years.

S. Bharati, et al. [72] developed, with a sustainable approach, a low cost mouldable for low temperature applications using steelmaking slag as raw materials. The ladle slag generated after the secondary steelmaking process was used in the 50–70% range as a complete source of CaO to develop a CAC. The slag was used as a 100% replacement for the limestone and partial replacement of the Al2O<sup>3</sup> source in the cement. In this way, it was possible to eliminate the CO<sup>2</sup> emission associated with the dissociation of the limestone during the clinker manufacturing process. The castable was prepared using primary steel slag as an aggregate and slag cement was developed as a binder. The CA and CA2 phases were detected as primary phases in the slag cement and gehlenite and mayenite as secondary phases.

The slag was used as a 100% replacement for the limestone and a partial replacement for the Al2O<sup>3</sup> source in the cement. Therefore, it was possible to eliminate the CO<sup>2</sup> emission associated with the dissociation of limestone during the clinker manufacturing process. The castable was prepared using primary steel slag as an aggregate, and slag cement was developed as a binder. CA and CA2 were formed as the primary phases in the slag cement, with the Gehlenite phases. Slag cement with a slag content of 60% exhibited superior strength compared to commercial medium purity CAC. In addition, the crush strengths of 110 ◦C and 1000 ◦C were found to be better for casting slag cement than commercial cement. Therefore, it was possible to develop a green mold using by-products from the steel manufacturing process that would not only help reduce the carbon footprint, but also reduce manufacturing costs.
