钒铁炉渣对矾土基自流浇注料性能的影响

以矾土、钒铁炉渣、硅灰为主要原料,铝酸盐水泥为结合剂,制备了矾土基自流浇注料.测试了试样的常温抗折强度、耐压强度、烧后线变化率,利用X射线衍射(XRD)分析了烧后试样的物相组成,采用扫描电子显微镜(SEM)观察和分析了烧后试样的显微结构.结果表明:随着矾铁炉渣加入量的增加,1 10℃烘后试样强度逐渐降低,1350℃烧后试样强度先增大后减小,试样的体积密度略有降低,形成的镁铝尖晶石相逐渐增多,试样烧后线变化率由收缩转为膨胀;引入适量的矾铁炉渣,有益于矾土基浇注料烧结强度的提高,同时能够有效保持材料的体积稳定性,其最佳加入量为40％.     

Effect of Synthesized Forsterite Addition on Properties of MgO Based Castables

High purity forsterite with a mass ratio 60：40 of MgO over SiO2 was synthesized using magnesite, caustic magnesia and natural silica as starting materials. The synthesized forsterite aggregates were added in magnesia based custable with MgO -SiO2 -H2 0 binding system to replace dead burned magnesia up to 60 mass% at an in- terval of 15 mass%. Effect of the forsterite addition on properties ~f MgO based castables was investigated. Micro- structure analysis of related specimens was carried out by means of SEM. Special grade bauxite powders were also in- corporated to form spinel by reaction with magnesia, ac- companying volumetric expansion to compensate high tem- perature shrinkage. Bulk density of the castable decreases with increased forsterite addition. Properties in terms of cold crushing strength and cold modulus of rupture, hot modulus of rupture at 1 400 ℃ and thermal shock resist- ance can be improved by adding an appropriate amount of the forsterite aggregate, preferably around 30 mass%.     

Preparation and characterisation of self-flowing refractory material containing 971U type microsilica

Abstract

A newer composition of self-flowing low cement brown fused alumina castable containing 971U type microsilica was developed. Optimum flow characteristics were achieved using water addition of 4·6?wt-%. This batch was sintered at different firing temperatures up to 1500°C. To understand the effect of both firing temperatures and corresponding phases, the present castable was characterised in terms of X-ray diffraction, scanning electron microscopy, bulk density (BD), apparent porosity (AP), water absorption (WA), cold crushing strength (CCS) and self-leveling flowability. The results revealed that gradual increase in firing temperature from 1100 through 1500°C caused low AP and WA, and high CCS properties due to the densification of the castable.     

Effect of zirconia particle size on the properties of alumina-spinel castables

The industrial application of alumina-spinel refractory castables has crucial requirements on the service performance. Thus, the effects of different sized desilicated zirconia particles on the castables microstructure, thermal-mechanical properties and high temperature elastic modulus have been investigated. The zirconia particle sizes were varied from 1000 µm to 2.5 µm (d₅₀). It was observed that the finer (below 88 µm) zirconia particles were beneficial to improve the cold modulus of rupture (CMOR) and the hot modulus of rupture (HMOR), but could not effectively enhance the thermal shock resistance. Fine zirconia particles can homogeneously disperse in the matrix and significantly promote the sintering process. Accompanied with the phase transformation of zirconia, both the high density of matrix cracks and the strong ceramic bonding (between the coarse grains and the matrix) were found in the refractory castables, which was responsible for an increase of CMOR. However, the binding characteristic could also give rise to the high stored elastic energy that was adverse to the thermal shock resistance, and the excessive amount of preexisting matrix cracks could induce more microdamage during the thermal shock. Additionally, it was proposed that the second-phase dispersion reinforcement and the highly ceramics bonding resulted in the superior HMOR when introducing fine ZrO₂ particles.     

钢纤维增强浇注料预制块在阳极焙烧炉炉墙上的应用

预焙阳极焙烧炉炉墙采用钢纤维增强浇注料预制块替代传统的小块异型砖 ,在国内尚属首次。应用结果表明 ,该方法在不改变焙烧技术条件的情况下 ,就可以完成阳极焙烧炉的大修和改造工作 ,具有投资省、节能效果好、寿命长和施工方便等特点。     

废镁铬砖加入量对镁质浇注料性能的影响

将回转窑烧成带废弃直接结合镁铬砖经过处理后,制成废镁铬砖再生料,用它替代镁质浇注料中的镁砂原料.文章研究了废镁铬砖的加入量对镁质浇注料性能的影响.结果表明:经过一定工艺处理后的废镁铬砖满足掺入要求,并且随着废砖加入量的增加,试样的烘干、高温和中温耐压强度、抗折强度、体积密度均逐渐增大.实验证明加入量为37%时,其性能指标接近对照试样,并对高温烧后试样进行了SEM及XRD分析.     

低水泥结合氧化铝空心球轻质浇注料的研究

针对氧化铝空心球的结构特点,采用低水泥结合、浇注成型的方式,对低水泥结合氧化铝空心球轻质浇注料的可行性进行了研究。经过相图理论计算、性能检测及X-射线衍射分析,结果表明,铝酸钙水泥不仅有利于提高材料的常温强度,并且对材料的高温烧结具有促进作用,材料的主要矿物组成为CA6和刚玉,材料的高温性能良好,使用温度可以达到1650℃以上。     

氧化铝微粉在轻质隔热浇注料中的应用研究

以超轻氧化铝质骨料为主要原料,铝酸钙水泥为结合系统,研究了不同含量氧化铝微粉对轻质隔热浇注料性能的影响。结果表明,轻质隔热浇注料的体积密度随着热处理温度的提高呈现先减小后增大的变化规律,并且随着氧化铝微粉含量的增加,体积密度增大。轻质隔热浇注料的抗折强度和耐压强度随着热处理温度的提高呈现先减小后增大的变化规律,并且当氧化铝微粉含量为5％时,材料的抗折强度和耐压强度最大。     

氧化锆空心球浇注料的研制

研究了氧化锆空心球的加入量、m-ZrO2微粉和不同添加剂对浇注料的物理性能的影响。结果表明,氧化锆空心球的加入量有一个较合适的范围。m-ZrO2微粉的引入,不仅可使浇注料有一个较合适的体积密度,又可使其强度提高。两种Mg0-Al2O3系添加剂均能大大提高浇注料的物理性能,并对材料的相组成产生影响,因而能提高其高温使用性能。     

石墨改性处理对Mg O-C浇注料性能的影响

本文用三种方法对石墨进行了改性处理,并研究了含这些处理石墨的镁炭浇注料的性能和组织结构。结果表明与含未处理石墨的浇注料相比,含处理石墨浇注料的各项性能都有了很大改善。其中含镁炭造粒颗粒的浇注料的强度和致密度相对最好,而以钛盐水解共沉积处理的石墨在浇注料中分布最均匀。