水泥含量对高纯铝尖晶石自流浇注料性能的影响

以致密刚玉和尖晶石为主要原料,铝镁尖晶石的含量为19%,在颗粒组成(5～0 mm)不变的情况下,研究了水泥含量分别为3%、8%和13%对高纯铝尖晶石自流浇注料性能的影响.结果显示1)随着水泥含量的增加,浇注料的加水量、干燥后致密度和强度均增加,但烧后致密度和强度都下降;2)水泥含量的变化对自流浇注料热态强度的影响不明显;3)随着水泥含量的增加,自流料烧后线变化增加,但水泥含量达到8%以后变化不明显;4)对于LF精炼炉渣,不管水泥的含量多少,自流料都不被渗透,但随水泥含量增加,自流料的抗熔蚀性变差;5)对于转炉钢包渣,随着水泥含量的增加,自流料的抗渗透性增强,抗熔蚀性变差,而渗透与熔蚀量之和减少;6)对于转炉末期渣,随着水泥含量增加,浇注料的抗渗透性增强,抗熔蚀性变差;7)应用相图分析了铝尖晶石浇注料的侵蚀机理,认为渣中Fe2O3或低熔点相CF的增加是渣渗透的主要原因.     

尖晶石加入量、水泥种类对刚玉-尖晶石浇注料高温抗折强度的影响

以板状刚玉、烧结尖晶石、氧化铝微粉和铝酸钙水泥为主要原料制备了铝酸钙水泥结合刚玉-尖晶石浇注料,研究了镁铝尖晶石加入量(质量分数分别为4%、7%、9%、11%、13%和15%)、铝酸钙水泥的类型(CA-270、CA-25R、CA-14M和Secar 71)对刚玉-尖晶石浇注料高温抗折强度的影响。结果表明:刚玉-尖晶石浇注料具有良好的高温抗折强度,试样的高温抗折强度受CA6高温结合相生成量、Al2O3固溶尖晶石的作用和原料带入的杂质高温下产生玻璃相共同作用的影响。在1 500~1 600℃范围内试样的高温抗折强度随着温度的升高而降低;在相同温度条件下,试样的高温抗折强度在尖晶石加入量为15%(w)时表现最好;不同种类水泥对试样高温抗折强度的影响主要表现为对高温结合物相CA6生成量的影响,同时水泥的细度和杂质含量对强度有明显影响,水泥越细,杂质越少,高温抗折强度越大。     

刚玉-尖晶石质自流浇注料的流动特性

采用流动台法对刚玉-尖晶石质自流浇注料的自由流动植进行了研究。着重于骨料的颗粒级配、骨料与粉料的比例对流动性的影响。研究发现,把试验配方按照Andreassen曲线拟合,即q＝0．22时,该浇注料的流动性好,自流值可达214mm。     

添加纳米氧化铝粉对铝尖晶石质自流浇注料性能和显微结构的影响

伊朗研究人员在铝尖晶石自流浇注料中加入质量分数分别为0、2%、4%的纳米氧化铝粉(比表面积为35 m2.g-1),研究了纳米氧化铝粉对浇注料常温耐压强度、显气孔率、显微结构和相组成的影响。研究表明:     

板状氧化铝质自流浇注料的蠕变研究

在不同应力和温度下，研究了两种不同硅微粉粒级对板状氧化铝质超低水泥自流浇注料的影响。由于莫来石形成使结构增强，故在1400℃下试验试样的蠕变与1300℃时相比显示出形变差异较小。由温差法获得的活性能显示随温度升高有减小的趋势。活性能的显著降低表明在骨料间成分中形成液相，控制选用的浇注料蠕变。     

添加氧化镁或尖晶石对氧化铝系浇注料的影响

1 前言 最近,作为钢包用氧化铝-氧化镁系浇注料受到了注目。与以往氧化铝-尖晶石系比较,两者都是以Al_2O_3和MgO为主要成分,化学组成大体相同。根据使用条件,一般氧化铝-氧化镁系的耐用性较优良。为了弄清影响其耐用性因素,从组织变化方面进行了研究。     

二氧化硅微粉对氧化铝-尖晶石浇注料性能的影响

对富含Al2O320%的MgO-Al2O3尖晶石和CaO1.7%及二氧化硅微粉添加达1.3%的浇注料的物理性能进行了研究。结果表明:加入0.1%的二氧化硅微粉有助于增加浇注料的高温抗折强度,而当加入量>0.1%时则非常有害。观察到二氧化硅微粉加入量为0.3%的浇注料在1500℃烧成3h后,由于CA6的形成,出现了最大的气孔率。当二氧化硅微粉的加入量>0.3%时,其气孔率降低的原因则是因为液相烧结。     

烧结尖晶石细粉加入量对刚玉-尖晶石浇注料性能的影响

为了改善刚玉-尖晶石浇注料的高温性能,以质量分数分别为10%的15~8 mm的白刚玉、58%的≤8 mm的白刚玉、5%的≤0.08 mm的白刚玉、14%的≤0.045 mm的白刚玉、9%的α-Al2O3微粉、4%的水泥制备了刚玉-尖晶石浇注料。在固定以5%(w)的≤0.048 mm的烧结尖晶石等量替代≤0.045 mm的白刚玉基础上,研究≤0.038 mm的烧结尖晶石等量替代≤0.045 mm的白刚玉的加入量(质量分数分别为1%、3%、5%和7%)对刚玉-尖晶石浇注料性能的影响。结果表明:烧结尖晶石细粉的添加可以改善材料的高温抗折强度和抗热震性能,并且在≤0.038 mm的烧结尖晶石细粉加入量为5%(w)时,试样的高温抗折强度最高,抗热震性最好。分析认为,刚玉在烧结尖晶石细粉中的固溶作用,对试样的高温性能影响较大。     

自流浇注料的研究

本文介绍了自流浇注料的研究及在水泥工业中的应用，探讨了超细粉对浇注料流动性的影响。自流浇注料用于水泥回转窑某些部位，不需振动，易于施工，并能延长使用寿命，改善工作环境。     

自流耐火烧注料流变学分析

利用宾汉姆体模型对耐火浇注料的流变参数进行了分析。认为研制自流耐火浇注料应兼顾以下四个方面：（１）颗粒级配；（２）超细粉的品种及加入量；（３）减水剂的品种及加入量；（４）水泥的矿物组成、细度和相应的添加剂     

Revisiting CA6 formation in cement-bonded alumina-spinel refractory castables

This work revisits the proposed mechanisms presented in the literature for CA₆ formation in Al₂O₃-MgO and Al₂O₃-MgAl₂O₄ castables bonded with calcium aluminate cement. New experimental tests, thermodynamic simulations and re-evaluation of the chemical composition and microstructural aspects observed for samples fired in the temperature range of 1150 °C to 1500 °C were carried out. Based on these data, a new interpretation of the CA₆ generation process, as well as the features which influence the location and morphology of this phase were proposed. CA₆ formation via solid and liquid states are suggested to take place in all evaluated compositions, where the former (solid-state) is the main reaction predicted for the silica-free refractories (AM0MS and AS0MS), whereas the liquid-state one prevails in the AM1MS and AS1MS materials. The CA₆ crystal morphology should be affected by these different reaction mechanisms. According to the experimental results, it was also discussed the role of the calcium hexaluminate features in the overall corrosion behavior of the designed refractories when they were placed in contact with molten slag at high temperatures. Such aspects have not been previously reported in published papers related to this subject.     

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.     

水泥窑用耐火浇注料的开发及应用

本文介绍了水泥窑用耐火浇注料的研究和应用情况。实际使用表明，在水泥窑的某些部位，特别是在那些由于结构复杂或窑体变形而不适宜采用砖的部位，采用浇注料更适宜。     

基质组成对铝镁质浇注料性能的影响

研究了电熔刚玉、电熔镁砂、镁铝尖晶石等细粉的配比变化对铝镁质浇注料性能的影响。结果表明 ,基质中同时引入一定量的刚玉、镁砂及合成镁铝尖晶石 ,有利于提高浇注料的综合性能 ;当基质中MgO与Al2 O3之比处于尖晶石理论组成附近时 ,材料的综合性能表现较好 ;由镁砂和刚玉粉反应生成的原位尖晶石 ,比加入的预合成尖晶石对提高浇注料性能更能产生积极的影响 ,但原位尖晶石的生成量过大时会导致材料的综合性能下降。     

结合剂对铝镁浇注料烧后膨胀行为的影响

研究了硅灰、水泥的加入量对铝镁浇注料高温烧后膨胀行为的影响,结果表明：硅灰、水泥的引入影响浇注料的物相组成及显微结构,严重制约其高温烧后线变化,为了在使用中获得适当的残余膨胀,应合理控制浇注料中硅灰和水泥的加入量。     

Influence of Synthesized Super Al2O3 Powder on the Properties of Alumina Castable

The in fluence of three different Al2O3 powder on self-flowing alumina castable was studied.Maximum compaction of sample was computed by Andresen Equation.The result showed that the Al2O3 powder.which has much smaller particle size,could improve the microstructure and the mechanical properties of castable under room temperature and high temperature.With the same powder size,the room tem perature strength of the castable added with Al2O3 powder properties of which were altered by adding mineralizing agent,was higher than that of the castable added with common Al2O3 powder ,but the flowability of these three different castable was almost the same.     

尖晶石微粉对铝镁质钢包浇注料性能的影响

研究了尖晶石微粉（MgO15．98％）的加入量对铝镁质浇注料作积密度、显气孔率、强度、热震稳定性及抗渣侵蚀与渗透能力的影响。当尖晶石微粉的加入量为2％～4％时,铝镁质浇注料的性能较好。微粉粒径、加入量、MgO的含量等诸因素相配合是很重要的。     

Role of cement content on the properties of self-flowing Al2O3 refractory castables

In this work, Al₂O₃ self-flowing castables (SFCs) were produced based on various cement contents. The SFCs were sintered at 1273 K, 1573 K and 1773 K and the exhibited properties were experimentally determined. Among the properties determined in this work are bulk density (BD), apparent porosity (AP), water absorption (WA), cold crushing strength (CCS), modulus of rupture (MOR) and fracture toughness (K_IC). It is found that additions of 5% cement lead to SFCs with maximum MOR and K_IC values after firing at 1773 K. Firing at 1573 K leads to a reduction in both, MOR and K_IC. In SFC containing 3% cement, maximum K_IC values of 3.53 MPa m^1/2 were achieved after firing at 1573 K. In the low cement SFCs (1 wt%) after firing at 1773 K the exhibited K_IC values were below those obtained in either the SFC-3 or SFC-5, but they were significantly high (3.43 MPa m^1/2).