Interactions between pyrite and silicates are very critical to ash slagging in coal-fired boilers. However, no work has been reported regarding the impacts on such interactions of CO₂, the dominant component in the oxy–fuel combustion gas. This was investigated in the present work by using mixtures of pyrite and kaolinite, a prevailing silicate mineral in coal. Furthermore, the sintering strength of the generated products was also evaluated. The pyrite–kaolinite mixtures were treated on a fixed bed reactor in both N₂ and CO₂ for comparison. The treating temperature was 1050, 1150 and 1250 °C while the reaction time was 3, 6 and 12 min, respectively. The solid products were characterized by techniques such as X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Sintering tests of these products were carried out as well. It was found that some interactions between pyrite and kaolinite took place in the N₂ atmosphere. This was evidenced by the formation of iron aluminosilicate and attributed to the effects of water vapor released from kaolinite dehydroxylation. Nevertheless, pyrite–kaolinite interactions in N₂ were limited and had insignificant effects on product sintering strength development. In CO₂, pyrite–kaolinite interactions were significantly enhanced, compared with those in N₂. Although the kaolinite-derived water vapor had some effects, CO₂ was found to play a dominant role. Enhanced pyrite–kaolinite interactions resulted in an increase of eutectic phases. Consequently, the product sintering strength development was greatly elevated. It was further found that, under the conditions investigated, the interactions between pyrite and kaolinite were actually through reactions between FeO, rather than other intermediates, and aluminosilicate. This new finding enabled us to develop the mechanisms for pyrite–kaolinite interactions in N₂ and CO₂.

黄铁矿和硅酸盐之间的相互作用对于燃煤锅炉中的灰渣非常关键。但是，尚未有关于影响含氧燃料燃烧气体中主要成分CO _2的相互作用的工作的报道。在本工作中，通过使用黄铁矿和高岭石（一种在煤中占主导地位的硅酸盐矿物）的混合物进行了研究。此外，还评估了生成产物的烧结强度。黄铁矿-高岭石混合物在固定床反应器中同时在N ₂和CO _{2中进行处理}进行比较。处理温度为1050、1150和1250℃，而反应时间分别为3、6和12分钟。通过诸如X射线荧光（XRF），X射线衍射（XRD）和具有能量色散X射线光谱法（SEM-EDS）的扫描电子显微镜的技术来表征固体产物。还对这些产品进行了烧结测试。发现在N ₂气氛中黄铁矿和高岭石之间发生了一些相互作用。铝硅酸铁的形成证明了这一点，这归因于高岭石脱羟基释放出的水蒸气的影响。然而，N ₂中的黄铁矿与高岭石的相互作用是有限的，对产品烧结强度的发展影响不大。在CO _2中与N ₂相比，黄铁矿与高岭石的相互作用显着增强。尽管衍生自高岭石的水蒸气具有一定作用，但发现CO _2起主要作用。黄铁矿-高岭石相互作用的增强导致共晶相的增加。因此，大大提高了产品的烧结强度。进一步发现，在所研究的条件下，黄铁矿与高岭石之间的相互作用实际上是通过FeO（而不是其他中间体）与铝硅酸盐之间的反应进行的。这一新发现使我们能够开发出黄铁矿与高岭石在N ₂和CO _2中相互作用的机理。