Industrial by-products have been used as an alternative raw material for the long-term storage of CO₂ as a mineral carbonate with various polymorphs and properties. For example; desulfurization gypsum (DG) obtained from a power station has great potential due to its high CaO content. This study used a mineral carbonation process to produce CaCO₃ particles (PCC) from DG wastes for fixation of CO₂ The effects of solid-to-liquid ratio (1:13, 1:9, and 1:7) and hydroxide sources (NaOH, NH₄OH) on properties of PCC were determined using XRD, SEM, FTIR, AAS, and wet chemical analyses. Calcite crystals were produced in all cases with the use of NaOH, whereas calcite crystals along with spherical vaterite crystals were observed in the presence of NH₄⁺. This study suggested a good option due to not only fixation of CO₂ but also production of PCC with a high purity.

Steelmaking slag is a good alternative material for the fixation of CO₂ gas as precipitated calcium carbonate (PCC) that are of used in many industrial applications such as paint, plastic, medical and so on. Therefore, the experimental conditions for production of PCC from steelmaking slag produced in Iskenderun Steelmaking Industry were determined via indirect carbonation process. At first, the influences of acid concentration, liquid-to-solid (L/S) ratio, particle size, reaction time and temperature on the dissolution of Ca from steelmaking slag were investigated, respectively. We determined that all parameters had strong effects on the dissolution of Ca from steelmaking slag except for the reaction time. Also, the effects of Na/CH₃COO ratio, CO₂ flow rate, reaction temperature and time on the precipitation of Ca ions as PCC particles were investigated. The properties of PCC were determined using chemical, SEM, XRD and particle size analyses. Furthermore, non-reacted CO₂ left from the carbonation reactor was stored in the lab-scale gasometer tank for the re-use in that process.