电冶矾土刚玉质自流浇注料的研究

以电冶矾土刚玉为骨料有利于提高浇注料的自流性能 ;六偏磷酸钠分散剂对Al2 O3泥浆流变性能有较理想的改善作用 ;电冶矾土刚玉质自流浇注料具有优良的抗渣性能 ,这主要同浇注料的显微结构和电冶矾土刚玉骨料的性能相关。     

微粉对刚玉质自流浇注料性能的影响

研究了由四种Ａｌ２Ｏ３微粉制得的泥浆的流变性能及对刚玉质自流浇注料性能的影响。研究发现,由环缝磨制备的电熔白刚玉微粉制得的泥浆具有优良的流动性能,微粉泥浆的流动性同微粉原料的晶相组成、组织结构、粒径分布和粉碎设备有关。浇注料中加入适量的优质微粉,能显著提高浇注料的流动性,改善刚玉质自流浇注料的组织结构     

α-Al2O3微粉和水泥对刚玉质自流浇注料性能的影响

研究了α-Al2O3微粉和纯铝酸钙水泥的加入量对刚玉质自流浇注料性能的影响.结果表明α-Al2O3微粉和水泥的加入量分别为6%和4%(质量分数,下同)时,基质料泥浆具有较低的粘度,可获得低加水量(4.5%)、高流动度(105%)、性能良好的刚玉质自流浇注料.     

氧化铝微粉与减水剂对刚玉质浇注料施工性能的影响

研究了减水剂(包括六偏磷酸钠和萘系、三聚氰胺类及聚羧酸盐类3类减水剂)、氧化铝微粉(包括烧结氧化铝微粉和活性氧化铝微粉)对纯铝酸钙水泥结合刚玉质浇注料的流动性能和力学性能的影响。结果表明:1)氧化铝微粉的平均粒度对浇注料的流动度有较大的影响,在一定范围内,粒度越粗,浇注料的初始流动性越小,可工作时间越短。2)氧化铝微粉中可溶性碱性氧化物的含量对浇注料的施工性能和可工作时间有一定的影响。3)减水剂既影响浇注料的需水性,还影响浇注料的强度发展,必要时需引入缓凝剂或者促硬剂进行调节。4)综合比较萘系、三聚氰胺类及聚羧酸盐类3类减水剂,以聚羧酸盐类减水剂的减水效果较好。     

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。     

刚玉质自流浇注料流变性和流动性的关系

以电熔白刚玉、SiO2微粉、α-Al2O3微粉、纯铝酸钙水泥和Alphabond为原料配制刚玉质自流浇注料,用全组分浇注料流变仪和L型流动性测试装置,研究了不同种类和加入量的微粉(加入SiO2微粉质量分数6%～8%或α-Al2O3微粉质量分数1%～4%)、1%～4%的结合剂(纯铝酸钙水泥或Alphabond)对自流浇注料流变性和流动性的影响。结果表明:(1)随着SiO2微粉和α-Al2O3微粉加入量的增加,刚玉质自流浇注料的剪切扭矩和相对塑性黏度下降;自流值随SiO2微粉加入量的增多而增大。(2)水泥加入量的变化对刚玉质自流浇注料流变性和流动性的影响很小;随Alphabond加入量的增加,剪切扭矩和相对塑性黏度显著增大,而自流值呈增大的趋势。(3)刚玉质自流浇注料的流变性与流动性之间存在一定的关系:相对塑性黏度与自流时间T30有较好的线性相关性,而与自流值无明显关联。     

低硅刚玉自流浇注料的研制

以刚玉为主要原料 ,并辅以纯铝酸钙水泥和其它外加剂 ,研制出了Al2 O3含量达 98% ,CaO含量 2 %的自流浇注料 ,其烧后体积密度 2 .98g·cm- 3,常温耐压强度 94.4MPa ,常温抗折强度2 0 .4MPa,均超过了国外同类产品的性能指标。     

影响自流浇注料性能的因素

本文以85均质矾土为自流浇注料的主要原料,纯铝酸钙水泥为结合剂,研究了不同减水剂对自流浇注料施工性能的影响;不同促硬剂对自流浇注料脱模强度的影响;不同热处理温度对自流浇注料体积密度和强度的影响。研究结果表明:减水剂B的加入能够使喷煤管用浇注料实现自流,而减水剂A的加入虽然可以改善喷煤管用浇注料的流动值,但不能使浇注料实现自流。促硬剂B能够明显提高自流浇注料的脱模强度,而促硬剂A对自流浇注料的脱模强度没有明显影响。因此,减水剂B与促硬剂B适宜做为自流浇注料的外加剂,掺量选为0.2%和0.003%较为合理。     

Self-flowing Cement-free MgO Castables Using a New Additive Package

Although high-performance basic refractory materials play an essential role in state-of-the-art steel-making,magnesia castables have not been widely used until now. A major challenge is that brucite formation( Mg( OH)2) during Mg O hydration causes volume expansion and subsequent cracking—a phenomenon commonly called slaking. To overcome problems related to slaking,a new specialty product,Siox X- Mag,has recently been developed for cement-free Mg O castables based on Mg O- SiO 2- H2 O bond. Specimens from industrial-scale-sized blocks after dry-out were characterised by SEM and XRD techniques. Using Siox X- Mag in combination with microsilica,cracking caused by brucite formation is suppressed. The results demonstrate that the dosage of microsilica plays essential roles in the crack formation in large samples. Furthermore,the compatibility of Siox X- Mag with different types of basic aggregates, medium to high-grade dead-burned magnesia and olivine, has also been evaluated. High-performance,self-flowing cement-free Mg O castables have been developed.     

不同种类再生刚玉对刚玉浇注料性能的影响

分别以板状刚玉、钢包再生刚玉、精炼炉再生刚玉为骨料,以板刚玉(≤0.074 mm)α-Al2O3微粉(D50=1.8 μm)、纯铝酸钙水泥及外加剂等原料为基质制作刚玉浇注料,研究了不同种类再生刚玉对刚玉浇注料性能指标的影响.结果表明:钢包再生刚玉及精炼炉再生刚玉的加入,导致刚玉浇注料的气孔率增大,体积密度、常温强度减小,抗渣性下降等.     

不同微粉对刚玉质浇注料性能的影响研究

在刚玉质低水泥浇注料中分别引入SiO2微粉和Al2O3/SiO2凝胶粉,研究了试样经烘烤(110 ℃×24 h)和烧成(分别为1100 ℃×3 h和1500 ℃×3 h)后的气孔率、体积密度、线变化率、抗折强度及耐压强度等物理性能.研究结果表明:在刚玉质低水泥浇注料中加入Al2O3/SiO2凝胶粉和SiO2微粉均能有效地降低气孔率,提高其体积密度和强度;但微粉的引入使试样的线变化率增大,且随着热处理温度的提高,影响更加显著.微粉的引入可以有效地改善浇注料中物料的填充行为及烧结行为,从而提高浇注料的密度与强度;在浇注料中加入6wt%的SiO2微粉或6wt%的Al2O3/SiO2凝胶粉可使浇注料获得较好的综合物理性能.     

Effects of Tabular Corundum Types on Properties of Corundum-spinel Castables

The corundum-spinel castables were prepared by six kinds of tabular corundum as aggregates,respectively,and their linear change rate on heating,apparent porosity,bulk density,cold modulus of rupture,cold crushing strength,hot modulus of rupture and thermal shock resistance were compared and studied. The results show that: 1) the six tabular corundum materials have similar main chemical composition but their physical properties vary for the different technical procedures which result in different properties of castables; 2) the optimal properties of corundum-spinel castables correspond to different tabular corundum types,so the corundum type shall be selected according to the application of the castables.     

Effects of Specific Surface Area and Impurities of Reactive Alumina on Properties of Corundum Based Castables

Effects of specific surface area and tiny amount of impurities of reactive alumina on the workability,sintering and high temperature mechanical strength of corundum based castables were investigated. The results show that the presence of reactive alumina with high specific surface area leads to accelerating of the hydration of calcium aluminate cement,thus shortening the working time and setting time of the castables,which can be ascribed that the critical energy barrier for stable nuclei of hydration products of cement can be reduced by the high specific surface area of reactive alumina. The sintering of the corundum based castables can be accelerated by the reactive alumina with high specific surface area and high amount of impurities, however, the reactive alumina with too high specific surface area and impurities can also lead to noticeable shrinkage of castables. In addition,high temperature mechanical strength of corundum based castables can be decreased by the higher amount of trace impurities of reactive alumina due to formation of lowmelting phase at high temperatures.     

Influence of Dispersants on Flow Ability of Colloidal Alumina Bonded Corundum Castables

In order to make corundum castables satisfy more severe service conditions in high temperature industries, colloidal alumina due to the same main component with corundum castables was introduced for a pure binding system. The influence of three dispersants(citric acid, FS10 and urea) on the flow ability of colloidal alumina bonded corundum castables was researched to choose a suitable dispersant for solving the shaping problem. In order to further understand the influence of dispersants on the flow ability and the mechanism, the rheological property and Zeta potential value of the colloidal aluminadispersant system and the matrix-colloidal alumina-urea-water system were tested. The results show the castables added with the urea have the best flow ability, and the appropriate addition of the urea is 0.5%.     

锆莫来石加入量对刚玉质耐火浇注料抗热震性的影响

以电熔刚玉、锆莫来石、α-Al2O3微粉为主要原料,以铝酸钙水泥为结合剂,制备了刚玉质耐火浇注料.研究了锆莫来石加入量(质量分数分别为0、3％、6％、9％)对刚玉质耐火浇注料物理性能、物相组成和显微结构的影响.结果表明:随着锆莫来石加入量的增加,110℃×24 h烘干后试样体积密度呈先增大后减小,显气孔率呈先减小后增大趋势,常温抗折强度变化不大;1600℃×3h处理后耐火浇注料试样体积密度和常温抗折强度呈先增大后减小的趋势,1500℃×0.5 h高温抗折强度呈明显下降趋势.锆莫来石的引入对刚玉质耐火浇注料的抗热震性有所提高.综合各项性能,认为锆莫来石的最佳加入质量分数为3％.     

NSP窑用刚玉质浇注料侵蚀损毁的热力学分析

NSP窑用刚玉质耐火浇注料,受碱(K2O)侵蚀,经热力学分析,α-Al2O3可以转变为钾β-Al2O3,形成K2O·11Al2O3固溶体,造成浇注料体积膨胀而损毁.