耐火浇注料自损坏机理探讨

对实际生产中常见的耐火浇注料粉化现象进行了分析 ,认为高铝水泥浇注料的自损坏机理为高铝水泥水化产物被大气中的酸性气体 (CO2 、SO2 、H2 S)侵蚀 ,导致水化物分解 ,结合强度下降 ,引起高铝水泥耐火浇注料粉化、剥落。另外 ,随着浇注料中水分的蒸发 ,盐类物质不断向蒸发面迁移、析出 ,其中一部分含结晶水的盐类 ,进一步失去结晶水 ,伴随着体积变化 ,加剧了浇注料的损坏过程     

高铝水泥结合浇注料的碳酸化现象

本文研究了高铝水泥结合的轻质浇注料的碳酸化现象,得到了如下结果: 1) 碳酸化反应速度在20℃的温度下比在30℃的温度下快。这主要是由于20℃时在轻质浇注料中生成的不稳定的CAH_(10)迅速进行碳酸化反应所致。 2) 碳酸化反应速度随着湿度的增加而增大。这是由于在高湿度下,与CAH_(10)相比,难于发生的C_2AH_8迅速进行碳酸化反应的缘故。 3) 碳酸化反应速度在部分浸渍于水中的轻质浇注料时显著增大。我们在水蒸发和碱集中的浇注料表面观察到了崩溃和剥落。这是由于伴随水的移动而造成碱的集中,促进碳酸化反应所致。 因此,碳酸化反应的最有效的因素是轻质浇注料中水的移动。 为了防止碳酸化反应,阻止水的移动颇为重要。我们已证实了在轻质浇注料的表面涂抹防水剂,能够抑制高铝水泥的碳酸化反应。     

耐火浇注料的非正常损坏原因及解决措施

耐火浇注料因其与耐火砖相比所特有的性质,越来越被广泛应用。在此主要提出了耐火浇注料使用时非正常损坏的原因有锚国件的脱落、温度的变化、窑的不正常操作、错误施工等。相应解决措施有正确选择锚固件材质和焊条材质、提高浇注料的热震性能、提高施工质量等。     

超低水泥高铝质不定形耐火浇注料的研究

通过采用超微粉和高效外加剂等技术，制备了超低水泥高铝质不定形耐火浇注料（简称为“ULCC”）。采用正交试验设计法，考察了SiO2微粉，Al2O3微粉，铝酸盐水泥和外加剂对ULCC性能的影响。结果表明，混合超微粉的最佳性能掺量为ω（Al2O3微粉）：ω（SiO2微粉）：ω（CA）：ω（外加剂）=3：4：2：0．2；且研制出的ULCC经110℃烘干后的抗折、抗压强度均较低，而经850℃和1300℃热处理的抗折、抗压强度显著提高；不足的是研制的ULCC线性收缩较大。     

抗铝浇注料的开发与应用

用小柴胡激发加减治疗变应性鼻炎６５例，收到较好疗效，说明小柴胡汤具有抗变态反应，抗炎和调整患者免疫功能，减轻鼻腔炎症反应的作用。     

低水泥浇注料的热疲劳

1 前言 耐火材料损耗大致可分为:因炉渣、处理剂与耐火材料反应而引起的蚀损和因热应力造成的龟裂所引起的剥落损毁。 关于各种窑炉产生的蚀损现象,通过对其使用后的材料进行分析,或在实验室评价的基础上,根据热力学的研究进行了系统的整理。 关于剥落损毁,虽然逆井等人正在着眼于成为其原因的龟裂,而不断进行破坏机理的剖     

低水泥自流型浇注料的研究与应用

本文叙述了新型低水泥、低水份、自流型硅酸铝质系列的浇注料的注料的研究与应用。这类产品在设计方面与现在常用的低水泥浇注料类似,用普通的混凝土输送泵喷入/注入,或用搅拌车搅拌后注入,容易施工修补。将其流动性及工作性能与普遍低水泥浇注料进行了比较。在钢铁、水泥、氧化铝、窑炉等工业中为满足施工方便及节省时间的要求都可用混合浇注技术。     

矾土基均质料在水泥窑用高铝高强耐火浇注料中的应用研究

本研究分别以Al2O3含量在80%的矾土基均质料和Al2O3含量在85%的矾土熟料作为骨料来制备水泥窑用耐火浇注料。研究了矾土基均质料和矾土熟料的理化性能,并测试分析了以这两种原料作为骨料制备水泥窑用高铝高强浇注料的性能。结果表明:⑴以矾土基均质料为骨料制备的耐火浇注料在体积密度上略低于以矾土熟料为骨料制备的耐火浇注料体积密度;⑵以矾土基均质料为骨料制备的耐火浇注料除体积密度外其它物理性能均优于以矾土熟料为骨料制备的耐火浇注料;(3)进一步证明了矾土基均质料作为骨料更加适合制备水泥窑用高铝高强耐火浇注料。     

粘土结合耐火浇注料的研制

选用山东特级焦宝石、贵州焦宝石、河南三级高铝矾土熟料和山西阳泉特级高铝矾土熟料为骨料 ,河南三级高铝矾土熟料和山西阳泉特级高铝矾土熟料的球磨粉为基质 ,广西软质粘土为结合粘土 ,三聚磷酸钠、六偏磷酸钠、柠檬酸钠、酒石酸钠、酒石酸钾钠、碳酸钠 6种钠盐作分散剂 ,铝 60高铝水泥作促凝剂 ,配制了 4种不同组成的粘土结合耐火浇注料。在试验研究的基础上 ,分析了不同分散剂对广西软质粘土的分散效果 ,分散剂在粘土 -水体系中的分散机理和不同骨料对粘土结合耐火浇注料性能的影响。结果表明 :分散剂的分散效果以六偏磷酸钠为最好 ;以广西软质粘土作结合剂 ,用烧结良好的特级高铝矾土熟料作耐火骨料研制的粘土结合耐火浇注料 ,用水量少 ,气孔率低 ,结构致密 ,强度高     

水泥和水合氧化铝对铝镁浇注料性能的影响

固定电熔白刚玉、电熔镁砂粉、αAl2O3微粉、SiO2微粉等原料的含量不变,分别加入不同量的水合氧化铝和纯铝酸钙水泥作结合剂(ρAl2O3加入量为2%、3%和4%,水泥加入量为3%、5%和7%),对比研究了水泥结合和水合氧化铝结合铝镁浇注料的显气孔率、体积密度、耐压强度、抗折强度、抗热震性和抗渣性能。结果表明:与水泥结合铝镁浇注料相比较,水合氧化铝结合浇注料具有更好的抗热震性、抗渣侵蚀和渗透性能;水合氧化铝在浇注料中的合适加入量为3%;水泥结合铝镁浇注料具有较高的常温强度,但其抗渣侵蚀和渗透性能随着水泥含量的增加而逐渐降低。     

Crack-free caustic magnesia-bonded refractory castables

A growing interest in designing high-alumina MgO-bonded refractory castables has been identified in recent years due to the magnesia ability to react: (i) with water at the initial processing stages of these materials (inducing the precipitation of brucite phase) or (ii) with alumina, giving rise to in situ MgAl₂O₄ generation at high temperatures. Nevertheless, despite the great potential of caustic magnesia to be used as a binder in such systems due to its high reactivity, it is still a challenge to control the hydration reaction rate of this oxide and the negative effects derived from the expansive feature of Mg(OH)₂ formation. Thus, this work evaluated the incorporation of different contents of aluminum hydroxyl lactate (AHL) into caustic magnesia-bonded castables, aiming to control the brucite precipitation during the curing and drying steps of the prepared samples, resulting in crack-free refractories. The designed compositions were characterized via flowability, setting behavior, X-ray diffraction, cold flexural strength, porosity, permeability and thermogravimetric measurements. According to the results, instead of Mg(OH)₂, hydrotalcite-like phases [Mg₆Al₂(OH)₁₆(OH)₂.4.5H₂O and Mg₆Al₂(OH)₁₆(CO₃)·4H₂O] were the main hydrated phases identified in the AHL-containing compositions. The addition of 1.0 wt% of aluminum hydroxyl lactate to the designed castable proved to be, so far, the best option for this magnesia source, resulting in the development of a crack-free refractory with enhanced properties and greater spalling resistance under heating.     

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.     

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。     

基质组成对高铝质浇注料荷重软化温度的影响

研究了基质组成对低水泥高铝质浇注料荷重软化温度的影响。结果表明 ,在骨料组成不变的情况下 ,以纯铝酸钙水泥取代复合水泥以及分别在基质中引入适量蓝晶石、α Al2 O3微粉和莫来石 ,浇注料的荷重软化温度均有显著提高     

The role of hydraulic binders on magnesia containing refractory castables: Calcium aluminate cement and hydratable alumina

Previous work by the authors has shown that the effects of calcium aluminate cement (CAC) and hydratable alumina (HA) can modify the magnesia hydration behavior in aqueous suspensions. As a consequence of these studies, the present paper highlights how varying the content of these binders can affect magnesia hydration in refractory castables using pH, apparent volumetric expansion, mechanical strength and porosity measurements and hydration–dehydration tests. Furthermore, as mechanical strength, porosity and refractoriness also play an important role in these materials, binder-free, magnesia-free and magnesia-and-binder-free samples were also tested as references. It was found that the deleterious effects of magnesia hydration can be greatly minimized by the binder and its selection content.     

莫来石结合碳化硅浇注料的研制

对碳化硅含量在 70 %以上的莫来石结合碳化硅质浇注料进行了试验研究。结果表明 :该浇注料从常温到 150 0℃均有较高的强度 ,并且 150 0℃烧后表面不氧化 ,可在 150 0℃及 150 0℃以下的高温环境中应用     

Molten salt synthesis of a SiC coating on graphite flakes for application in refractory castables

A silicon carbide coating was formed on the surface of graphite flakes by reaction of molten Si with carbon at 1100–1300 °C in a 95%KCl-5%NaF molten salt under Ar atmosphere. The effect of temperature and Si/graphite ratio in the initial mixture on the quality and the amount of SiC were investigated by XRD and SEM/EDS analyses. Also, the water wettability, oxidation resistance and zeta potential of un-coated and coated graphite were examined by TGA analysis and sedimentation test. The results show the amount of coating to increase in the coated flakes with increasing temperature and Si/graphite ratio. The SiC coating improves water wettability of graphite and acts as a protective layer to enhance oxidation resistance. The zeta potential of coated graphite was also increased which indicated a better dispersion in water based systems. These improvements in both the water dispersivity and oxidation resistance of SiC coated graphite would make it as promising candidate raw materials for application in C-containing refractory castables.