定形耐火材料的高温耐磨性研究

用高温耐磨试验装置研究了高铝砖、刚玉砖、氮化硅结合碳化硅砖和黏土结合碳化硅砖4种定形制品在高温下的耐磨性。结果表明:耐火制品的磨损量随温度的变化曲线可分为两种类型,非氧化物材料(氮化硅结合碳化硅砖)的磨损量-温度曲线接近水平直线,即在整个试验温度区域中(25~1 400℃)磨损量几乎没有变化;氧化物(或氧化物结合)耐火制品(高铝砖、刚玉砖和黏土结合碳化硅砖)在一定温度范围内磨损量变化不大,温度达到某值以上,磨损量大幅度降低,此温度对应为该种材料开始塑性变形温度。高铝砖、刚玉砖、黏土结合碳化硅砖磨损量开始明显下降的温度点分别为800、1 000和600℃。影响不同材质耐火砖的高温耐磨性的因素有物相组成、玻璃相性质以及工艺因素等。     

酸性铬铁渣对耐火材料侵蚀的试验研究

为了研究冶炼铬铁的竖炉炉缸用耐火材料受酸性渣侵蚀情况,利用化学试剂CaO、MgO、SiO2、Al2O3和铬铁矿配制了不同碱度(分别为0.31、0.45和0.55)的酸性铬铁渣,采用静态坩埚法,分别在1500℃、1550℃、1580℃保温3h条件下,对高铝质、莫来石质、铝碳质、铝碳化硅质、刚玉-莫来石质、刚玉质和棕刚玉-碳化硅质等耐火材料进行侵蚀试验,比较了不同耐火材料被侵蚀和渗透的程度。试验结果表明:随着铬铁渣碱度和温度的增加,耐火材料的侵蚀量都有所增加;铬铁渣对铝碳砖的侵蚀和渗透程度均很轻,对莫来石砖和棕刚玉-碳化硅砖的较轻;而对刚玉、刚玉-莫来石砖渗透程度很严重,但侵蚀很轻;对高铝砖和铝-碳化硅砖侵蚀程度严重。     

β-SiAlON结合刚玉砖的高温力学性能与显微结构

以常用的刚玉砖和低蠕变高铝砖作对比材料,研究了β-SiAlON(包括氧化铝基β-SiAlON和矾土基β-SiAlON)结合刚玉砖的高温力学性能、显微结构特征和断裂特征。结果表明:(1)β-SiAlON结合刚玉砖在1 400℃时的抗折强度是刚玉砖和低蠕变高铝砖的5倍以上,其塑性变形开始温度和粘滞流动开始温度都较刚玉砖和高铝砖的高200~300℃,在相同条件下,其高温蠕变变形率仅为低蠕变高铝砖的10%~20%;(2)在β-SiAlON结合刚玉砖中,主晶相刚玉颗粒构成了砖体的骨架结构,原位生成的β-SiAlON晶体填充于刚玉颗粒的间隙中,与粒状刚玉结合紧密,这种结构特征增强了复合材料的高温力学性能;(3)在1 400℃高温下,β-SiAlON结合刚玉砖的断裂方式是以穿颗粒断裂为主的混合断裂。     

耐火材料的发射率与温度、波长关系的研究

玻璃熔窑在高温条件下运行,用光学高温计或红外辐射温度计测定砌筑玻璃熔窑的耐火材料温度,测得的是耐火材料的亮度温度。要得到耐火材料的实际温度,必须要先得到耐火材料的发射率。本研究测定了砌筑玻璃窑炉常用的五种耐火材料,即硅砖、粘土砖、高铝砖、镁砖和锆刚玉砖的发射率。镁砖为镁铬砖,锆刚玉砖为33~#电熔锆刚玉砖。测定了在不同的温度和波长条件下,可见光谱范围内五种耐火材料的发射率。     

煤焦浆气化炉用耐火材料的选择

采用回转抗渣法进行氧化锆砖、高纯刚玉砖、铬刚玉砖、86高铬砖和90高铬砖等不同材质耐火材料抗石油焦渣侵蚀能力的对比试验,并采用扫描电镜和X衍射等分析方法对侵蚀试验砖的显微结构进行了观察与分析,研究了不同材质耐火材料抗石油焦渣侵蚀能力的差异.结果显示:90高铬砖抗石油焦渣侵蚀能力最好,试验前后厚度几乎无变化;氧化锆砖最差,侵蚀厚度达14 mm;不同材质耐火材料抗侵蚀性能优劣的顺序为:90铬砖>85铬砖>铬刚玉砖>刚玉砖>氧化锆砖.     

危废处理焚烧炉内衬用耐火材料研究进展

对常用的危险废弃物焚烧炉内衬用耐火材料的种类进行了综述，指出不同工作环境使用的内衬耐火材料主要有刚玉质、碳化硅质、莫来石质、黏土质、铬刚玉质、刚玉-碳化硅质、刚玉-莫来石质、镁铝质等，总结了内衬耐火材料损毁的机制，包括机械磨损、热剥落和化学侵蚀，并对危废焚烧炉内衬用耐火材料的发展方向进行了展望。     

巩义市金荣耐火材料有限公司

正公司占地50余亩,建筑面积10000多m~2,四栋现代化钢构车间内拥有40m~3超高温(1750℃)梭式窑四座,大吨位数控压力机10余台。主要生产氧化铝空心球砖、刚玉砖、锆英石砖、锆刚玉砖、莫来石砖、硅线石砖、碳化硅砖、低气孔砖、三低砖、高铝砖等高、中档耐火制品及散装耐火材料,广泛用于冶金、化工、玻璃、陶瓷、熔块、电力、铝合金、垃圾焚烧、耐火     

巩义市金荣耐火材料有限公司

正公司占地50余亩,建筑面积10000多m~2,四栋现代化钢构车间内拥有40m~3超高温(1750℃)梭式窑四座,大吨位数控压力机10余台。主要生产氧化铝空心球砖、刚玉砖、锆英石砖、锆刚玉砖、莫来石砖、硅线石砖、碳化硅砖、低气孔砖、三低砖、高铝砖等高、中档耐火制品及散装耐火材料,广泛用于冶金、化工、玻璃、陶瓷、熔块、电力、铝合金、垃圾焚烧、耐火     

耐火材料耐磨性的研究

总结了不同材质类型的耐火材料耐磨性差异,探讨材料物相组成、结合相状态、工艺控制等因素对耐火材料耐磨性强弱的作用;同时,研究了耐火浇注料试样的热处理温度对试样磨损量的影响,以及以试样的原砖面和切开面分别作为试验面对材料磨损量结果的影响。结果表明:以碳化硅、刚玉为主要物相的耐火材料具有高的耐磨性,以莫来石、石英、方镁石为主要物相的材料则耐磨性较差。当耐火浇注料试样的热处理温度高于耐磨试验温度时,试样的磨损量偏大。试验面选择原砖面和切开面的试验结果有明显的差异,两者的磨损量相差10%以上,其原因与材质等因素相关。     

水泥旋窑常用耐火材料的品种及消耗

水泥旋窑可分为传统窑和新型干法窑。传统窑包括湿法窑、干法窑和立波尔窑。这类窑虽然生产工艺不尽相同,但对耐火材料的要求基本一致。新型干法窑是指预热器(SP)窑和预分解(PC)窑。这类窑,尤其是日产2000吨以上的大型窑,对耐火材料的要求很高。目前我国传统的耐火材料多数由冶金系统和地方的耐火材料厂供应,而大型新型干法窑的耐火材料,则主要依赖进口。 1 水泥旋窑常用的耐火材料 水泥旋窑主要用铝质和镁质两类耐火材料。镁质材料也称碱性材料。常用的铝质材料有粘土砖、高铝砖和磷酸盐结合铝质砖;镁质材料有普通镁铬砖、直接结合镁铬砖和尖晶石砖。此外,常用的还有耐碱粘土砖。现     

Slag Resistance of Refractories for Direct Reduction of Laterite Nickel Ores in Rotary Kilns

Aiming at prolonging the service life of refractories for direct reduction of laterite nickel ores in rotary kilns, the slag resistance of ten materials(corundum bricks, chrome corundum bricks, silicon nitride bonded silicon carbide bricks, high alumina silicon carbide bricks, high alumina bricks, magnesia chrome bricks, magnesium aluminate spinel bricks, spinel chrome corundum bricks, chrome corundum castables and magnesia alumina chrome composite spinel bricks) was evaluated by rotary slag tests, which simulate the service conditions in rotary kilns. The corroded residual bricks were analyzed by SEM and EDS. The results show that the magnesia alumina chrome composite spinel brick possesses the advantages of magnesium aluminate spinel bricks and chrome corundum bricks; MgO-rich spinel can absorb the penetrated ferric oxide, and forms a dense zeylanite layer, which prevents the penetration of the molten laterite nickel ores; therefore, it is an ideal lining of rotary kilns for direct reduction of laterite nickel ores.     

Use of aluminum phosphate as a bond for refractory corundum products and washes

Summary The use of aluminum phosphate is desirable for preparing corundum products and washes based on commercial calcined alumina.A composition was developed ensuring strong bonding of corundum refractories and also of corundum refractories with steel and graphite.The bonded refractory components (corundum) are tightly held on graphite components of thermocouples after 15 h operation in the walls of electric arc furnaces at 2000°C.Aluminophosphate bond increases the spalling resistance of corundum products and also raises their strength.     

水泥-聚丙烯酸复合结合快硬耐磨涂抹料

为了克服现有耐磨涂抹料涂抹性能差、硬化速度慢、强度低等缺点,以低铝莫来石、棕刚玉、高铝矾土为主要原料,采用纯铝酸钙水泥和聚丙烯酸乳胶作为复合结合剂,研制了配比(w)为低铝莫来石(5～1 mm)29%,低铝莫来石(1～0.09 mm)24%,棕刚玉(≤0.09 mm)16%,高铝矾土(≤0.02 mm)8%,硅灰8%,纯铝酸钙水泥15%,聚丙烯酸乳胶9%(外加),耐热钢纤维4%(外加),三聚磷酸钠+有机酸0.3%(外加)的快硬耐磨涂抹料,并进行了现场试用。结果表明:研制的涂抹料从常温养护到500℃处理后都具有较高的常温强度和较好的耐磨性;现场试用发现,研制的快硬耐磨涂抹料易于涂抹,硬化时间短,使用寿命长,有望作为快速修补料或在平均温度<500℃的衬体中取代现有的磷酸盐结合涂抹料。     

Solid particle impact erosion of alumina-based refractories at elevated temperatures

Solid particle erosion tests have been conducted on three different alumina-based refractories at elevated temperatures up to 1400 °C, using sharp SiC particles between 325 and 830 μm in diameter. The impact speed is 50 m/s and the impact angle is varied between 30° and 90°. The objective of this study is to ascertain the effects of temperature and impact angle on the erosion resistance of alumina refractories. The experimental results reveal that the alumina-based refractories, in general, exhibit increasing erosion resistance with increasing temperature and decreasing impact angle, with the minimum erosion rate at 1200 °C and 30° impact angle. Chrome corundum refractory brick is the most resistant to vertical erosion, due to its highest alumina content, and associated hardness and density, as well as strongly bonded aggregate and binder phase. The primary material removal mechanisms are fracture and chipping of binder phase and aggregate, as well as aggregate pull-out.     

Properties of some high alumina refractories obtained from different alumina sources

Within the same alumina level, refractories made using different sources of alumina vary widely in their densification and refractory properties. Refractories based on the more volume stable synthetic mullite and sillimanite grains are dense and more creep resisting than the continuously bloating easily deformed bauxite ones. The mineralogical composition of the grog grain used and the matrix developed in a fired brick appears to be the most important factor determining its resistance at high temperatures.     

Effect of some technological parameters on the properties of corundum refractories

Conclusions In producing corundum refractories from commercial alumina, the technological parameters of the process can be altered widely with respect to their action on the properties of the goods. The basic parameters are firing temperature, grain-size composition, and the quantity of corundum chamotte, the method of preparing the commercial alumina used as the bond, the incorporation of TiO₂ as additive, and the firing temperature of the goods.By changing the technological parameters it is possible to manufacture products with different porosities and strength values, and also with a high resistance to creep under load at high temperatures.It is also necessary to set up a production cycle for corundum refractories in which it is possible to alter widely the technological parameters required for manufacturing goods with basic properties, providing real variety in their service conditions.A technology was developed for producing corundum refractories the creep resistance of which at high temperatures and loads make them promising materials for use in high-temperature gas and air heater units of blast furnaces.Translated from Ogneupory, No.2, pp. 46–54, February, 1970.     

A PROGRESS REPORT ON THE DEVELOPMENT OF AN ABRASION TEST FOR REFRACTORIES AT HIGH TEMPERATURES1

A report of progress in the development of a method of testing refractories for their resistance to abrasion at high temperatures. The method developed consists of a steel chisel point moving back and forth over faces of the brick clamped together. Eleven brick are tested at one time. The chisel is actuated by means of a jack hammer and is water-cooled. The blow delivered vanes from 6.5 inch-pounds at the beginning of the test to 13 inch-pounds under the most severe conditions. The chisel has a rounded point l/8-ch radius and 1 inch wide. Data show that the principle is correct and capable of differentiating between brick of varying resistances to abrasion at tempcratures as high as 1350°C.     

Synthesis and two-step sintering behavior of sol–gel derived nanocrystalline corundum abrasives

Nanocrystalline corundum abrasive with mean crystal size of less than 100 nm was synthesized by two-step sintering method using sol–gel process. A remarkable suppression of grain growth was achieved by controlling sintering temperature and taking advantage of sintering aids during the final stage of a two-step sintering process. The grain size of the high densification samples (>99% theoretical density) produced by two-step sintering method was about 10 times less than the samples made by the conventional sintering technique. The microstructure of the samples was homogeneous without abnormal grain growth and the sol–gel derived corundum abrasive with two-step sintering technique exhibited excellent mechanical properties and wear resistance compared to those sol–gel derived corundum abrasive with conventional sintering methods and fused corundum abrasive.