Lithium based high temperature sorbent from copper slag: Synthesis and CO2 capture performance
Peng Li, Jiang Zhou, Hongwei Guo, Wei Zhao, Feng Zheng, Yijian Chen, Bingji Yan, Dong Chen
Abstract
Using high temperature CO 2 sorbent for carbon capture is an effective approach to reduce carbon footprint. Copper slag , as an abundant metallurgical waste containing substantial amount of Si and Fe resources, was being explored as cheap raw material for the preparation of lithium-based sorbent. The results shows that the lithiation is initiated at 450–600 °C, where fayalite and magnetite in slag are firstly oxidized by released water vapor from the decomposition of LiOH, then further react with Li 2 O to form Li 4 SiO 4 and LiFeO 2 . As the temperature rises, the conversion of LiFeO 2 to Li 5 FeO 4 and incorporation of Fe 3+ , Al 3+ into Li 4 SiO 4 lattice occur in parallel. The resulting sorbent exhibited excellent CO 2 chemisorption ability with a capture capacity of 420 mg/g material at 725 °C. Particularly, even in the gas stream containing 5 vol% CO 2 , it showed a CO 2 uptake capacity of 383 mg/g material. In the CO 2 cycling tests, the sorbent suffered a decay in sorption capacity, which was ascribed to the poor regeneration ability of Li 5 FeO 4 . Comparatively, it possesses a relatively high capacity of 241 mg/g material in 20 vol% CO 2 after 20 cycles, which is higher than those of previously reported Li-silicate sorbents derived from wastes.