SiC-Si废料制备耐火材料的研究
发布时间：2018-03-15 07:12
本文选题：SiC-Si废料 切入点：氧化 出处：《济南大学》2017年硕士论文 论文类型：学位论文
【摘要】：太阳能光伏所需晶体硅片加工过程中产生大量的切割废料浆。干燥后固态切割废料除含少量聚乙二醇外,主要成分为SiC、Si,因此称之为SiC-Si废料。本课题首先研究了某晶体硅片厂排放的SiC-Si废料的组成及其升温氧化过程,在此基础上采用烧结法直接制备了硅质耐火材料,并通过调整废料中Al2O3的掺量制备了性能优良的多孔和莫来石质耐火材料。利用这种固体废弃物制备耐火材料有助于减轻企业的环保压力,并降低耐火材料的生产成本。实验通过XRF、XRD、TG、SEM等现代测试手段对SiC-Si废料原粉和氧化料、制备的耐火材料进行了分析,探讨了不同温度、升温速率和粒度对废料氧化性的影响以及制备工艺对耐火材料形成、结构和性能的影响。通过大量实验,确定了该废料制备硅质、多孔和莫来石质耐火材料的最佳配比及工艺参数。成分分析显示所用SiC-Si废料中含有62.63%SiC和27.49%Si,这些成分可作为制备耐火材料的硅源。结合20-1500℃范围内的非恒温和恒温热重分析以及X射线衍射分析结果,可以看出SiC-Si废料的升温氧化过程包含Si的氧化、Fe的氧化和SiC的氧化三个阶段,完全氧化后的产物是方石英和Fe2O3。球磨预处理和以较低的升温速率升温更有利于SiC-Si废料的氧化。单独以SiC-Si废料为原料采用烧结法成功制备了以方石英为主晶相的硅质耐火材料。最佳制备工艺条件为:在50MPa压力下制坯,以3℃/min的升温速率升温到1550℃,烧结6h。所得试样中SiO2含量为94.86%,体积密度为1.75g/cm3,抗折强度为23.32MPa,耐火度可达1680℃。SiC-Si废料中的SiC高温氧化会产生SiO2和碳氧化物气体,Fe会被氧化成Fe2O3,通过调整配料中Al2O3的掺量,可在高温热烧结时形成液相,同时碳氧化物气体被这种液相包裹难以排出,从而成功的制备了多孔耐火材料。研究表明,当Al2O3掺量为20%时,SiC-Si废料在1515℃烧结2h可制备出多孔耐火材料。烧结所得试样体积密度为0.78g/cm3,室温导热系数为0.354W/(mK),耐火度可达1560℃,可作为高温隔热保温材料使用。SiC-Si废料的氧化产物以SiO2为主,为获得莫来石相含量较高的耐火材料,需在原料中加入67~80%的Al2O3。实验比较了氧化铝掺量、烧结温度、烧结时间对烧结体中莫来石生成的影响。结果表明,当氧化铝掺量为75%,烧结温度为1550℃,烧结时间为2h时,热处理后的试样莫来石相含量最高,可达92.99%。试样的体积密度为1.63g/cm3,耐火度超过1800℃。
[Abstract]:A large amount of cutting waste slurry is produced during the processing of crystal silicon wafer required for solar photovoltaic. The solid cut waste after drying contains a small amount of polyethylene glycol. The main component is sic Si, so it is called SiC-Si waste. Firstly, the composition of SiC-Si waste discharged from a crystal silicon wafer plant and its heating and oxidation process are studied. On this basis, silicon refractories are directly prepared by sintering method. The porous and mullite refractories with excellent properties were prepared by adjusting the amount of Al2O3 in the waste materials. In addition, the production cost of refractories was reduced. The raw powder and oxidizing material of SiC-Si waste were analyzed by means of modern testing methods such as XRF, XRD, TG-SEM, and the different temperatures were discussed. The effects of heating rate and particle size on the oxidation of the waste and the effect of the preparation process on the formation, structure and properties of the refractory. Optimum proportioning and technological parameters of porous and mullite refractories. Composition analysis shows that the waste SiC-Si used contains 62.63sic and 27.49Si. these components can be used as silicon source for the preparation of refractories. Combined with non-constant temperature and constant temperature in the range of 20-1500 鈩，
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