镁铝尖晶石不烧滑板砖的研制与使用

本文介绍镁铝尖晶石不烧滑板砖的研制及使用情况,探讨了其基质的组成、碳及添加剂的加入对制品性能的影响,对制品的性能及使用情况进行了分析。研究表明:以电熔镁铝尖晶石和电熔镁砂为原料,加入适当的石墨和添加剂,以酚醛树脂作结合剂可制得性能优良的镁铝尖晶石不烧滑板砖。经武钢第一炼钢厂试用,其效果令人满意。     

镁铝尖晶石粉体的性能、制备与应用趋势

近20年来,镁铝尖晶石制备技术及应用发生了根本性变化.过去用于耐火材料、耐磨材料、陶瓷工业的镁铝尖晶石粉体,逐渐应用于功能材料、激光晶体材料等高技术领域.综述了高性能镁铝尖晶石的性能、以及制备技术的发展状况和应用前景.特别指出粉体纯度是一个重要性能指标.     

添加轻烧氧化镁对镁铝尖晶石轻质耐火材料烧结性能的影响

以工业氧化铝和重烧氧化镁为原料,通过添加轻烧氧化镁微粉的方法,合成了镁铝尖晶石轻质耐火材料,考察了添加轻烧氧化镁微粉对一步煅烧法制备的镁铝尖晶石轻质耐火材料烧结性能的影响.研究结果表明,添加轻烧氧化镁微粉对镁铝尖晶石的烧结具有明显的促进作用,烧结温度越高越有利于镁铝尖晶石的合成.     

镁铝尖晶石的合成与应用

镁铝尖晶石的合成方法有电熔法和烧结法。利用镁铝尖晶石研制的耐火材料主要有尖晶石浇注料、镁铝尖晶石碳砖、方镁石－尖晶石砖等，可用于钢包内衬及水泥回转窖、活性石灰窖等，抗侵蚀性能好，使用寿命长。     

镁铝尖晶石对钢液脱碳的影响

通过高温实验,研究了镁铝尖晶石对钢液脱碳反应的影响,利用热力学分析了镁铝尖晶石对钢液脱碳的作用机理.研究结果表明:高温(1 900 K)下镁铝尖晶石对钢液具有明显的脱碳作用,加热温度、钢中[C]含量以及镁铝尖晶石成分是影响钢液脱碳的主要因素;钢水脱碳量随着加热温度和钢中w[C]的升高而增加;镁铝尖晶石的化学成分对钢液脱碳有重要影响,其中以钢中[C]与MgO组分的反应为主要反应,与MgAl2O4的反应为次要反应.     

全天然原料合成活性镁铝尖晶石的研究

1 前言现代工业技术的不断发展,要求耐火材料的性能相应提高。镁铝尖晶石熔点高,热膨胀系数低,导热性好,抗化学侵蚀能力强,是一种性能优良的碱性耐火原料。在日本及一些欧洲国家人工合成的镁铝尖晶石正推广应用于钢包内衬、水泥窑衬、玻璃窑蓄热室砖等。在我国,镁铝尖晶石原料正处于开发应用之中。镁铝尖晶石原料可分为电熔     

预处理铝灰制备镁铝尖晶石研究

采用铝灰制备耐火材料是其高附加值资源化利用的一个方向,以预处理后的无害化铝灰为主要原料,利用烧结法合成镁铝尖晶石材料。借助XRD、SEM及EDS等对烧结试样的晶型组成及微观形貌进行了分析。结果表明:利用预处理后铝灰添加部分氧化镁可制备出物理性能优良的耐火材料,烧结后的主要物相为镁铝尖晶石,烧结温度对产品性能影响较大,适宜的烧结温度为1 650℃。     

镁铝尖晶石质耐火材料

介绍了尖晶石质耐火材料的种类、生产方法、制品的性能指标、应用领域及有关的使用效果,分析了组成对制品性能影响的规律。镁铝尖晶石(一般简称尖晶石)     

镁铝尖晶石质耐火材料的合成

以MgAl2O4为骨料,MgO和Al2O3为基质料,通过固相烧结法合成了镁铝尖晶石质耐火材料,考察了原料组成、骨料粒度和成型压力对一步烧结法合成镁铝尖晶石烧结性能的影响.结果表明,随着基质料含量的增加和骨料粒度的增大,试样的线变化率和显气孔率逐渐增大;随着成型压力的增加,试样的显气孔率明显减小,线变化率增加.以镁铝尖晶石(粒度＜177μm)为骨料,按镁铝尖晶石,氧化镁,氧化铝的摩尔比为20:40:40配料,在200MPa压力下成型,可以获得显气孔率较低、线变化率适宜的镁铝尖晶石质耐火材料.     

添加氧化铈对反应烧结制备镁铝尖晶石材料性能的影响

为了进一步提高高品质钢冶炼用镁铝尖晶石耐火材料的关键性能,以电熔镁铝尖晶石、轻烧氧化镁和白刚玉为原料,镁铝溶胶为结合剂,氧化铈为添加剂,采用反应烧结工艺成功制备了镁铝尖晶石材料.系统研究了氧化铈添加量(质量分数,0、3％,6％、9％和12％)对合成镁铝尖晶石材料显气孔率、体积密度、线收缩率、体积收缩率、常温耐压强度和抗...     

含尖晶石空心球的刚玉-尖晶石材料制备及性能

采用电熔-喷吹法制备了镁铝尖晶石空心球,结合空心球结构与性质特征,将其引入刚玉-尖晶石材料,对比研究了不同粒径空心球对材料显微结构、力学强度及隔热能力的影响.结果 表明:制备的空心球球形度高,球壁由单层或多层镁铝尖晶石晶粒镶嵌结合而成,球体的抗压能力取决于球壁厚度及其均匀性.降低粒径、引入复合粒径空心球,通过球体之间的...     

利用碳铬渣制备耐火浇注料的试验

对碳铬渣进行矿物分析,得知其矿物组成主要是镁橄榄石和镁铝尖晶石;研究了不同粒径骨料和不同煅烧温度对耐火浇筑料力学性能的影响。结果表明：级配合理的碳铬渣骨料,掺入适量的镁砂粉,以铝酸盐水泥为结合剂,经过1500℃煅烧,可以制备常温力学性能优异的耐火浇注料,其耐压强度大于110MPa,抗折强度可达12.74MPa。     

攀西地区白马钒钛磁铁矿工艺矿物学探讨

为了查明攀西地区白马钒钛磁铁矿工艺矿物学特征,利用化学分析、光学显微镜、扫描电子显微镜、矿物自动分析仪(AMICS)等先进的分析手段,对白马钒钛磁铁矿矿石展开了深入研究。结果表明,矿石的主要矿物为钛磁铁矿、钛铁矿、钙长石、透辉石和蛇纹石等。矿石中Fe、Ti、V的质量分数分别为25.05%、3.46%和0.13%,可以综合回收利用;其中有74.13%的铁以钛磁铁矿的形式存在,13.16%的铁以含铁硅酸盐的形式存在,有63.72%的钛以独立矿物钛铁矿及钛铁矿(客晶)的形式存在,33.67%的钛以类质同象形式存在于钛磁铁矿中。矿石中钛磁铁矿、钛铁矿和硫矿物均以中粒为主,钛铁矿(客晶)和镁铝尖晶石(客晶)的嵌布粒度绝大部分为微粒,小于0.010 mm。矿石中13.16%的铁赋存于硅酸盐中以及大部分钛磁铁矿中含钛铁矿(客晶)和镁铝尖晶石(客晶),是影响铁精矿品位的主要因素。     

Mechanism Study on the Formation of Liquid Calcium Aluminate Inclusion from MgO‐Al2O3 Spinel

A study on the formation mechanism of liquid calcium aluminate inclusions from MgO‐Al₂O₃ spinel was carried out. It was found that spinel reacted with dissolved Ca in liquid steel forming liquid calcium aluminate phase. Stability calculations showed good agreement with the experimental result. According to the thermodynamic calculation, liquid calcium aluminate inclusions would form from spinel even at very low level of dissolved Ca content at 1873 K. At lower temperatures, the compound CaO‐2Al₂O₃ was found to be the stable phase at the spinelmetal interface. Potential sources of dissolved Ca during ladle processes were also discussed.     

Formation of magnesium aluminate (spinel) in cast SiC particulate-reinforced Al(A356) metal matrix composites

Transmission (TEM) and scanning electron microscopy (SEM) are employed to study the SiC/Al-alloy interface in a cast SiC_p/Al(A356) metal matrix composite (MMC). Magnesium aluminate (spinel), MgAl₂O₄, was found at the interface as a reaction product after material processing. Comparisons of the crystal structure, structure factor, and interface reaction ther-modynamics between MgAl₂O₄ and MgO have been carried out. The results from these com-parisons confirm the experimental observation;i.e., the favored interface phase is magnesium aluminate (spinel). Based on the thermodynamic analysis, the presence of oxygen in various forms in the system during processing, such as SiO₂, A1₂O₃, and MgO, is believed to be the source which supplies the oxygen for the formation of MgAl₂O₄.     

Origins of Non‐metallic Inclusions and their Chemical Development during Ladle Treatment

In the present work, steel, slag and refractory samples were taken from the ladle at OVAKO Steel in Hofors, Sweden. The steel samples were analysed in LOM, SEM and OES PDA. The chemical compositions of the inclusions were determined by EDS. According to the morphologies and compositions, the inclusions were classified into 5 different types, namely, (1) type‐1, alumina inclusions, (2) type‐2, calcium aluminate, (3) type‐3, spinel+calcium aluminate, (4) type‐4, calcium aluminate surrounded by a CaS shell, and (5) spinel+calcium aluminate surrounded by a CaS shell. Ladle glaze was found to be a major supplier of the inclusions, while the inclusions brought over from EAF could be another important source. The results of OES PDA showed that removal of inclusions took place mostly during the vacuum degassing period.     

Observation on Physical Growth of Nonmetallic Inclusion in Liquid Steel During Ladle Treatment

The behaviors of several types of inclusions at a high temperature were examined using a confocal scanning laser microscope (CSLM, 1LM21H/SVF17SP). Although alumina inclusions tended to impact on each other, agglomerate, and grow quickly, no other inclusion type, such as spinel as well as solid and liquid calcium aluminate, was observed to attract each other. The results of confocal microscope study were compared with the industrial investigation. For this purpose, many steel samples were taken at different stages of ladle treatment. The samples were analyzed by scanning and light optical microscopes. Approximately 50,000 inclusions of several types were examined. Only alumina inclusions were attracted to each other and agglomerate. No agglomeration by attractive behavior was observed in the other types of inclusions, including liquid inclusions. Both the industrial data and the in situ observation by CSLM indicate that, although the attraction force and the agglomeration play a significant role in the growth of alumina inclusions, the agglomeration of spinel and calcium aluminate inclusions does not need special consideration in ladle treatment. The agglomeration of liquid calcium aluminate inclusions took place only when they occasionally met as a result of external force, which led to low collision probability. However, the agglomeration of the liquid calcium aluminate inclusions along with alumina particles could be detrimental in the casting process.     

镁处理高碳硬线钢中夹杂物

 为了研究镁处理对高碳硬线钢中夹杂物影响规律,采用扫描电镜-能谱仪、FactSage热力学软件研究了不同镁添加量下钢中夹杂物的成分、形貌、尺寸、数量和分布,计算了高碳硬线钢中夹杂物平衡成分和生成质量随镁添加量的变化,分析了镁处理对夹杂物熟化生长的影响规律。结果表明,高碳硬线钢中镁质量分数由0.001 0%增加到0.001 8%,夹杂物的转变路线为Al₂O₃→Spinel→MgO,夹杂物平均尺寸由1.68 降到1.39 μm,且夹杂物分布更加均匀。随着溶解氧含量的增加,夹杂物的粗化率增加。当钢中溶解氧含量相同时,镁铝尖晶石的粗化率最大,其次是氧化镁,氧化铝夹杂物的粗化率最小。高碳硬线钢中镁添加量为0～0.004%,夹杂物的粗化率先增加后减小,镁添加量为0.001%时,夹杂物的粗化率最大。     

120t BOF-LF-RH-CC流程GCrl5轴承钢洁净度研究

对“120 t BOF-LF-RH-CC”流程GCrl5轴承钢的洁净度研究结果表明,LF精炼结束以A1₂O₃ • MgO尖 晶石和Al₂O₃-MgO-CaO夹杂为主,RH真空处理后, Al₂O₃- MgO尖晶石几乎全部消失,钢中夹杂物以液态钙铝酸盐为主,T.0含量降至5.3x10^-6;浇注过程中间包重新成Al₂O₃- MgO尖晶石;RH终点和中间包钢水以及连铸坯未发现≥20um钙铝酸盐夹杂。