碱金属对煤灰熔融特性的影响机理  

Characteristics and Mechanism on Coal Ash Fusion

作　　者：刘欢欢 杜梅芳[1] 王要克 李明强[2] LIU Huanhuan;DU Meifang;WANG Yaoke;LI Mingqiang(College of science,University of Shanghai for Science and Technology,Shanghai 200093,China;School of Environment and architecture,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学理学院,上海200093 [2]上海理工大学环境与建筑学院,上海200093

出　　处：《材料科学与工程学报》2018年第6期985-992,共8页Journal of Materials Science and Engineering

基　　金：中国国家自然科学基金资助项目(51276212);国家科技支撑计划资助项目(2015BAA04B01);上海市科委计划资助项目(15dz1206500)

摘　　要：碱性矿物质是高碱煤灰沾污结渣的重要影响因素。本文首先通过影像式烧结点试验仪研究了一种准东高碱煤与四种非高碱煤灰的熔融特性,并利用电感耦合等离子体-原子发射光谱(ICP)、X射线衍射仪(XRD)对高碱煤灰熔融过程中元素迁移及矿物变化进行研究,在此基础上,进一步利用量子化学理论从微观层面分析了碱性矿物质降低高碱煤灰熔融温度的机理。结果表明:高碱煤比其他四种非高碱煤初始熔融温度低60℃到110℃;随着高碱煤制灰温度的升高,初始熔融温度也由700℃逐渐升高至770℃,初始熔融的量也随之降低,其沾污、结渣倾向减弱;灰中K_2SO_4、NaAlSiO_4参与灰中低温共熔体的生成,随着温度的升高其物相逐渐消失;灰中碱性矿物NaAlSi_3O_8的相变活性位点优先受到灰中K^+、Mg^(2+)、Na^+、Ca^(2+)等离子势较低的离子攻击,使其矿物体系中硅氧四面体[SiO_4]^(4-)与铝氧四面体[AlO_4]^(5-)分离成片段,进而发生分子段的重组,形成熔点更低的低温共熔体而增加灰中液相。Alkaline mineral effects on the fusion point of high alkali coal is reported in this paper. The movement and transformation of element and fusion characteristics of coal ashes was at first investigated, then the behavior how alkaline mineral lower the fusion point of the ash was analyzed using the quantum chemistry theory. The result shows the fusion point of ZD high alkali coal is about 60℃ to 100℃ lower than the others; With the increase of ash-making temperature, the fusion point increases from 700℃ to 770℃, the initial fusion amount decreases and it becomes harder to foul and slag; K2SO4、NaAlSiO4 participate in the formation of low temperature co-melting substance, then gradually dissolve with increasing temperature; Some low potential ions such as K+、Mg2+、Na+、Ca2+ etc. will attack the active-site of phase transition in NaAlSi3O8 and break the [SiO4]4- and [AlO4]5- tetrahedron chains into fragments, some of which will form another low fusion point co-melting substance and more liquid phase in the ash.

关 键 词：高碱煤 熔融特性 量子化学 相变活性位点 低温共融 

分 类 号：TQ534[化学工程—煤化学工程]