热态钢渣降温过程固定CO2机理研究

The cooling process of hot steel slag emits a lot of heat energy, it is an important developing trend of steel slag disposal at present that minimize the oxidation of metal Fe and performance improvement of slag in cooling process. Based on “using waste to treat waste” recycling development concept, mineral carbonation can solidify carbon dioxide to achieve carbon emission reduction and performance improvement of steel slag, namely carbon dioxide capture of exhaust gas by use of composition in steel slag, meanwhile lowing free calcium oxide contents. However, current understanding of steel slag carbonation technology is mostly adapted from room temperature, there are great differences in temperature, and the key elements of the coupling mechanism of carbon dioxide capture and performance improvement of steel slag are still unknown. Based on thermodynamic consideration of the gas-solid interface reaction of hot steel slag phase composite in various gas content. By theoretical analysis and experimental study, the influence rules of different atmosphere, slag particle size and temperature on carbon dioxide capture process, and change of phase composition, volume stability and gelation properties of steel slag before and after carbon dioxide capture are studied. Then propose the coupling associated with effects of carbon dioxide capture and performance improvement of Steel slag, and a model is expected to build in order to interpret the mechanism of the reactions and phase changes during the carbon dioxide containing gas cooling the steel slag.

热态钢渣降温过程释放大量热能，降温中实现减少金属Fe氧化同时改善渣性能是钢渣处置的发展趋势。基于“以废治废”循环发展理念，开展钢渣碳酸化研究——即利用钢渣组成固定废气中CO2，同时降低钢渣中的f-CaO含量，从而达到碳减排和改善钢渣性能的目的。但现有钢渣碳酸化技术研究大多是基于常温，同高温热态渣碳酸化的区别较大，另外关于CO2固定和渣性能协同改善的关键因素有待探明。本项目在开展了热态钢渣在不同气氛下的气-固相界面反应热力学分析基础上，结合理论分析与试验研究，研究气氛、颗粒度、温度等参数对钢渣固定CO2的影响作用，以及固定CO2前后对钢渣性能如矿物相组成、体积稳定性、胶凝性能的影响对比。在此基础上揭示CO2固定与渣性能协同改善之间的关联效应，以期构建热态钢渣CO2冷却的反应作用机理和物相转变分析模型。

钢渣中存在大量游离氧化物（f-CaO、f-MgO），容易吸水体积膨胀，严重降低了钢渣建材资源化利用率。针对此，本课题提出了并开展了利用热态钢渣降温过程产生的CO2对热态钢渣碳酸化改性的研究；分别对热态钢渣碳酸化高温实验及碳酸化反应机理、热态钢渣碳酸化对钢渣应用性能的影响和热态钢渣碳酸化与钢渣综合性能改善的协同作用进行了系统研究。.针对热态钢渣碳酸化高温实验及碳酸化反应机理研究，结合气氛组成、温度参数及钢渣颗粒度等参数，开展热态高温碳酸化实验，系统地研究碳酸化后的钢渣物相组成、化学组成及微观结构形貌，以及碳酸化反应中涉及到的气氛与钢渣之间的气-固相和固-固相的热力学反应规律和钢渣的碳酸化的反应动力学机制，确定了热态钢渣高温碳酸化的关键影响因素。.针对热态钢渣碳酸化对钢渣应用性能的影响进行研究，对碳酸化后的钢渣体积稳定性、胶凝性能和水化性能等建材应用性能的影响，分析其作用机理。.针对热态钢渣碳酸化与钢渣综合性能改善的协同作用分析，探讨热态钢渣碳酸化效果与碳酸化钢渣综合性能（物相组成、应用性能）的关联和协同作用机制，构建热态钢渣碳酸化及碳酸化钢渣综合性能协同改善参数模型，为热态钢渣碳酸化改性技术的工程应用提供理论支撑。