纯铝酸钙耐火水泥混凝土的试验

一、前言以水硬性纯铝酸钙水泥结合的浇注料,生产工艺简单,施工方便,节约能源,是目前国内外广泛使用的不定形耐火材料之一。近年来,由于使用耐火度高的低气孔率集料以及更纯的铝酸钙水泥,因此耐火混凝土的耐火度、体积稳定性及耐用性均得到提高。耐火混凝土的发展在冶金、化工、建材等行业以及有关热工设备的厂家使用中表明耐火混凝土具有与烧结耐火砖进行竞争的潜力,耐火混凝土的试验与应用已成为当前生产单位急需而具有重要现实意义的研究课题。二、纯铝酸钙水泥耐火混凝土的技术性能     

耐火预制件在水泥窑中的应用

耐火预制件是将不定形耐火材料定形化,兼具有定形和不定形的优点。本文针对耐火预制件的特点以及在原料配比、形状设计等方面的要求,根据水泥窑不同部位的使用条件,分别介绍了篦冷机矮墙及顶部预制件、三次风管弯道预制件、三次风管闸板预制件、窑头罩预制件,为水泥窑用耐火材料的长寿化提供了方法,具有良好的应用前景。     

新一代耐火混凝土的流变学

制备新型耐火混凝土时,主要的工艺问题在于,要使成型物系在极限浓度情况下具有必须的流动性。不同工艺阶段的机械载荷作用使凝固(触变)结构破坏,以及使用不同稀释添加剂(电解液)和流变性能调节剂可达到上述条件。机械工艺过程(混练,各种振动成型法)是调节混凝土混合料及混凝土应力变形状态和结构形成作用的强有力手段,因为它们存在有最重要的流变性能——触变性。触变性振     

阿利特-硫铝酸钡钙水泥混凝土耐火性能的研究

采用与普通硅酸盐水泥混凝土对比的方法,通过对阿利特-硫铝酸钡钙水泥混凝土试件经受高温作用时表观现象的观察分析和力学性能测试,详细研究了阿利特-硫铝酸钡钙水泥混凝土的耐火性能,探讨了该水泥混凝土在高温作用下的行为特征和性能变化规律。研究表明,高温作用下,阿利特-硫铝酸钡钙水泥混凝土内部水分的逸出比普通硅酸盐水泥混凝土阻力大,逸出温度滞后,爆裂现象略微严重;相同配合比下,经受600℃高温作用后,该水泥混凝土的剩余强度约为62%～68%,耐火性能较普通水泥混凝土好。     

浅谈耐火铝酸盐水泥的现状与发展前景

浅谈耐火铝酸盐水泥的现状与发展前景凌继栋，杨久俊郑州大学建筑工程学院（４５００５２）早在１９０９年，Ｓｈｅｐｈｅｒｄ等［１］便开始研究ＣａＯ－Ａｌ２Ｏ３二元系统相图，为加工制造耐火铝酸盐水泥奠定了理论基础。法国于１９１４年首次开发成功矾土（熔块）水泥...     

水泥窑里衬用镁铬质耐火混凝土

目前,开发水泥回转窑烧结带里衬用耐火混凝土生产工艺的工作仍在继续进行,其方向是根据资源储备和能源储备的最新原则,深化理论研究和扩大试验开发。 从这一观点出发,莫斯科国立建筑大学开发的耐火混凝土具有很大的意义,此种混凝土采用复合硅酸     

玻璃熔窑用低水泥耐火浇注料制品

玻璃熔窑所用耐火材料，全世界总的需求量共为75～100万t，其使用寿命目前已增至14年。     

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。     

Investigation of three-stage compressive creep of a spinel forming refractory castable containing 8% MgO

A spinel forming castable with an initial MgO content of 8%, commonly applied in refractory linings in the steel industry, was characterised with regard to the creep behaviour. Three creep stages were observed for 1300, 1400, and 1500 °C for application relevant loads between 3 and 8 MPa for sintered samples. The parameters of the Norton–Bailey creep model were determined for all three creep stages. The added microsilica increased the creep strain rate in the temperature range above 1300 °C. The fitting of the results for only one temperature carries the risk of over-fitting. This was observed for the first creep stage at 1400 and 1500 °C. Nevertheless, for the investigated material, it was not possible to achieve a common fit for a larger temperature range. The evaluation of the creep parameters by different combinations of measurements allowed to obtain statistical information about the creep parameters.     

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     

耐火浇注料衬里受冻试验研究

研究了常用的重质和轻质耐火浇注料在正常养护以及加入普通混凝土防冻剂后经受低温处理的性能变化 ,分析了耐火浇注料的低温冻害机理。认为只要在施工和养护期间采取适当的保暖措施 ,使其强度得以正常发展后即可解除保暖而不会影响衬里的性能。普通混凝土常用的防冻剂不利于耐火浇注料的高温性能 ,不能盲目使用。     

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.     

高铝水泥浇注料损坏现象研究

分析了在实际生产现场发生损坏的高铝水泥浇注料的表面析出物 ,证实了造成这一现象的直接原因是浇注料水化物的碳酸化、硫酸化和盐析效应。研究认为 ,改善养护条件以及水源质量可以减少浇注料损坏现象的发生。     

Re-examining the prospects of aluminous cements based on alkali-earth and rare-earth oxides

In the family of aluminous cements the potential of strontium aluminate, the strontium–barium aluminate and the barium aluminate cements have been sporadically and incoherently studied over several decades in various parts of the world and more particularly in the East European countries without much wide-spread commercial success. Attempts had also been made to extend the exploratory studies to the (Ca, Sr, Ba)O–Al₂O₃–ZrO₂–HfO₂ system to synthesize super-refractory binders.In fact, the above compositions, prima facie, seem to have the potential of arriving at cementitious formulations that, apart from being super-refractory, may as well be highly resistant to seawater, X-rays and gamma radiation.Looking at these potentials, quite a few experimental studies have been carried out under the guidance and supervision of the present author. The present paper is an endeavour to collate the data on some of these systems both from the published literature as well as from the author's findings. The prime motive has been to review and re-assess the prospects of manufacturing a range of new aluminous binders with superior properties.     

SM高效减水剂及锆英石对耐火浇注料性能的影响

研究了SM高效减水剂对浇注料流动值和力学性能指标的影响,以及添加锆英石粉对耐火浇注料热震后残余抗折强度的影响。结果表明,在试验范围内随SM加入量增大浇注料流动值增大,体积密度增大,显气孔率降低,耐压强度、抗折强度增大;随锆英石加入量增加,热震15次后残余抗折强度先增大后减小。     

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.     

低水泥自流耐火浇注料

简述了加有ＳｉＯ２、Ａｌ２Ｏ３微粉的高铝质低水泥自流浇注料中所涉及的化学过程。研究了ＳｉＯ２、Ａｌ２Ｏ３微粉、高铝水泥含量、加水量对低水泥耐火浇注料物理性能的影响。讨论了分散剂、促凝剂、延迟硬化剂在低水泥自流耐火浇注料中的作用。