Towards robust and reactive iron ore oxygen carriers: Potassium feldspar-induced lattice bridging for enhanced chemical looping combustion

Chemical looping combustion (CLC) represents a transformative CO₂ capture technology, yet its commercial viability is hindered by the rapid attrition of oxygen carriers under cyclic redox conditions. This study adopted a crystallographic engineering strategy to overcome the intrinsic brittleness of Fe-based oxygen carriers through potassium feldspar (KAlSi₃O₈) modification. In this work, iron ore-based composites were developed via two distinct synthesis pathways, i.e. premixed calcination (PC) and solid–solid co-fluidization (SF), to systematically investigate the effect of KAlSi₃O₈ loading (0.5–2 wt.%) on mechanical resilience and redox performance. A paradigm shift in oxygen carrier design is revealed: SF-derived composites with 0.5 wt.% KAlSi₃O₈ exhibit strong synergy between durability and reactivity, achieving a 40.5% increase in mechanical strength (5.60 N vs. PC’s 5.27 N) and a stabilized attrition rate of 0.019%/h—62% lower than unmodified counterparts. Remarkably, redox kinetics are simultaneously enhanced, with oxygen release activation energy reduced by 41.4% through anisotropic lattice oxygen transport pathways. Multi-scale characterization revealed the mineral lattice bridging mechanism: Ki₂TiO₃ fibers generated in situ extended into skeletal defects, forming three-dimensional bridging frameworks that redistribute fracture energy via edge effects and crack deflection. Techno-economic analysis demonstrates the scalability of this approach. While material costs rise marginally ($1.5–(Formula presented) vs. $1–(Formula presented) ), SF-modified carriers reduce annual replacement and CO₂emission costs by 50–85% and 50–75%, respectively. This work establishes a framework for designing fatigue-resistant oxygen carriers through natural mineral-inspired toughening strategies, bridging the gap between fundamental fracture mechanics and industrial-scale CO₂ capture technology implementation.