煤气化灰渣的规模化处置与利用对于煤化工高质量发展和煤炭行业的低碳转型至关重要。制备煤气化灰渣基多孔陶瓷材料是实现煤气化灰渣绿色化、高端化、规模化消纳的重要途径。然而,烧结温度过高仍然制约着煤气化灰渣基多孔陶瓷的规模化开发,通过调变煤气化灰渣灰熔融特性来降低烧结温度是多孔陶瓷制备的关键。为此,选取某水煤浆气化细渣的中炭组分(me-dium-carboncomponents,MCC)为研究对象,以镁渣为添加剂,利用X射线衍射、X射线荧光光谱、扫描电镜和FactSage热力学模拟计算等手段,研究了高温时MCC矿物组成演变规律,以及镁渣对MCC灰熔融温度和灰黏度的影响机理。结果表明:MCC主要矿物组成为石英、方解石和白榴石等,高温下MCC矿物组成会向低熔点钙长石和透辉石转化;镁渣主要成分为CaO和SiO2,以方解石、石英和菱镁矿等矿物形态存在;随着镁渣质量分数增加,MCC灰熔融温度呈先减小后增大趋势,向MCC中添加5%(质量分数,下同)和10%镁渣可促进混合样品中高熔点矿物质向低熔点钙长石-辉石体系转化,长石和辉石生成低温共熔体使体系灰熔融温度降低;此外,CaO和MgO等碱土金属氧化物对硅铝酸盐网状结构的解聚作用,使MCC临界黏度温度降低,黏度对温度的响应更快。

The large-scale disposal and utilization of coal gasification slag is crucial for the high-quality development of the coal chemical industry and the low-carbon transformation of the coal industry. The preparation of porous ceramic materials based on coal gasification is an impor- tant way to achieve the green, high-value and large-scale consumption of coal gasification ash and slag. However, the high sintering temperature still restricts the large-scale development of por- ous ceramics based on coal gasification ash and slag. The key to preparing porous ceramics is to adjust the ash melting characteristics of coal gasification ash by adding flux agents to reduce the sintering temperature. Therefore, the medium-carbon components (MCC) of a specific coal-wa- ter-slurry gasification fine slag were selected as the research object and magnesium slag was used as the flux agent. The evolution of MCC mineral composition at high temperatures and the influ- ence of magnesium slag on MCC ash melting temperature and ash viscosity were studied utilizing X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM) and FactSage thermodynamic simulation calculation. The results show that the primary mineral composition of MCC comprises quartz, calcite and leucite. At high temperatures, the mineral composition of MCC will transform into low melting point plagioclase and diopside. The main components of magnesium slag are CaO and SiO , which exist in the mineral forms of cal- cite, quartz and magnesite; as the mass fraction of magnesium slag increases, the ash melting temperature of MCC first decreases and then increases. Adding 5% (mass fraction) and 10% magnesium slag can promote the conversion of high melting point minerals to low melting point anorthite-pyroxene, the formation of a low-temperature eutectic of feldspar and pyroxene reduces the ash melting temperature of the MCC system; in addition, alkaline earth metal oxides such as CaO and MgO have a depolymerization effect on the network structure of aluminosilicate, resul- ting in a decrease in the critical viscosity temperature and a faster response of viscosity to temper- ature.