载氧体辅助燃烧(Oxygen Carrier Aided Combustion, OCAC)技术的协同固碱潜力得到越来越多学者的关注。以天然钛铁矿提钛后的尾矿及单一组分模化物Fe₂TiO₅和TiO₂作为吸收剂，以KCl和CH₃COOK作为模拟碱源，在静态吸收实验装置上研究了钛铁矿尾矿对碱金属钾的高温吸收特性，系统探究了时间、粒径、温度、质量比、气固组分等多种因素对吸收效果的影响规律，结合X射线衍射仪、电感耦合等离子体发射光谱仪、扫描电子显微镜和X射线能谱仪等表征手段，揭示了K在钛铁矿表面富集和体相迁移的微观机理。结果表明，钛铁矿尾矿在高温下具有较好的K吸收能力，吸收速率随时间增长表现出先快后慢的变化趋势。在一定条件下，减小颗粒尺寸、提高反应温度和气相中的K浓度，可进一步提升钛铁矿尾矿的固碱性能。在与实际工业烟气相似的温度和碱金属浓度条件下，钛铁矿尾矿对K的捕集率可达40%以上。钛铁矿尾矿的主相具有富Fe层和富Ti层交替排列的独特片层结构，且相较单一组分模化物具有更复杂的形态和更优异的固碱能力。其过程为：K首先在钛铁矿表面沉积并逐渐形成富集层，随后通过固相扩散向内渗入，并沿富Ti层深度迁移至颗粒内部；同时，富Ti层中的Fe逐渐向颗粒外层迁移，并对K在钛铁矿中的吸收产生双重影响。此外，Cl可通过与钛铁矿表面的Fe反应生成易挥发的FeCl₂而进一步促进钛铁矿对K的吸收，钛铁矿尾矿中铁钙铝榴石等脉石相对K亦具有十分显著的协同吸收作用。本文的研究结果进一步证实了OCAC技术的协同固碱潜力，同时为低品位钛铁矿的资源化利用提供新思路。

The synergistic alkali metals fixation potential of Oxygen Carrier Aided Combustion (OCAC) technology has attracted increasing attention. Using the tailings from natural ilmenite after titanium extraction and its individual components Fe₂TiO₅ and TiO₂ as absorbents, and KCl and CH₃COOK as simulated alkali sources, the high-temperature absorption characteristics of alkali metal potassium by ilmenite tailings were studied in a static absorption experimental setup. The effects of various factors such as time, particle size, temperature, mass ratio, and gas-solid components on the absorption performance were systematically investigated. Techniques such as X-ray diffraction, inductively coupled plasma optical emission spectrometry scanning electron microscopy and X-ray energy dispersive spectroscopy were used to reveal the micro-mechanisms of K enrichment on the surface and bulk phase migration within ilmenite. The results show that ilmenite tailings possess good potassium absorption capabilities at high temperatures, with the absorption rate displaying a trend of rapid increase followed by a slow decline over time. Under certain conditions, reducing particle size, increasing reaction temperature, and the concentration of K in the gas phase can further enhance the alkali fixation performance of ilmenite tailings. At the temperatures and alkali metal concentrations like those of actual industrial flue gases, ilmenite tailings can achieve a K capture rate of over 40%. The primary phase of ilmenite tailings has a unique lamellar structure composed of iron-rich and titanium-rich layers arranged alternately. Compared to single-component model substances, it has a more complex morphology and superior alkali fixation capabilities. The process involves an initial deposition of K on the ilmenite surface, forming an enriched layer, followed by a solid-phase diffusion inward and migration deep into the particle along the titanium-rich layers. Fe in the titanium-rich layers migrates synchronously outward, doubly impacting the absorption of K in ilmenite. Additionally, Cl can further promote the absorption of K in ilmenite by reacting with Fe on the surface to form volatile FeCl₂. Minerals such as almandine calcian in ilmenite tailings also show a significant synergistic absorption of K. The findings further confirm the synergistic alkali metals fixation potential of OCAC technology, while also offering new insights into the resource utilization of low-grade ilmenite.