Fatih Kutay Mete, Kağan Benzeşik*, Ahmet Turan, Maria Teresa Izquierdo, Onuralp Yücel

The potential of lithium orthosilicate (Li4SiO4) as a material to capture carbon dioxide (CO2) is being explored due to its excellent capture capability and thermal stability. Currently, a significant portion of the world's energy needs are met through the burning of fossil fuels, which leads to an increase in atmospheric CO2 and contributes to global warming. While fossil fuels will remain the primary source of energy for several more years, it is crucial to develop cost-effective and environmentally friendly technology for large-scale CO2 capture and storage before its release into the atmosphere in order to mitigate the associated greenhouse effect. This study focuses on optimizing the synthesis of lithium orthosilicate using a solid-state method to enhance CO2 capture. The research involves assessing the key characteristics of the synthesized material that improve CO2 capture efficiency. The starting materials used for comparison include lithium carbonate (Li2CO3), BF (blast furnace), BOF (blast oxygen furnace) and EAF (electric arc furnace) slags, and pure reagents of silicon dioxide (SiO2). The effect of process conditions, such as synthesis temperatures ranging from 850 to 950°C and varying holding times of 4, 6, 8, and 10 hours in a muffle furnace, were studied and compared. X-ray diffraction (XRD) analysis was performed to characterize the samples and slags. CO2 capture performance of the samples were evaluated in thermobalance test under 92 vol% CO2 (N2 balance) gas concentration at 600°C. As to conclude, carbon dioxide capturing sorbent material was produced by utilizing the slags generated as a by-product in steel production. Thus, considering the principles of circular economy, a material defined as waste was used as raw material for the production of another product used for lowering atmospheric CO2 levels.