A classification of refractories: Properties

A mineralogical petrographic classification of the properties of refractory materials is proposed. By convention, three major groups—phase-sensitive, structure-sensitive, and specific-sensitive—are considered. In terms of this classificatory system, three routes towards improving actual and developing new advanced refractory materials are suggested: a phase-oriented (mineralogical) route, a structure-oriented route, and a combined route.Translated from Novye Ogneupory, No. 6, June, 2004, pp. 25–27.     

Sialon结合SiC耐火材料的化学稳定性

采用高岭土、炭黑为主要结合相原料,合成了Sialon结合SiC耐火材料。考察了Sialon结合SiC耐火材料的氧化行为、高温碱侵蚀行为和冰晶石熔体的侵蚀行为。结果显示,合成Sialon结合SiC耐火材料具有高的机械强度和化学稳定性。     

Properties of periclase-carbon refractories containing metal powders

Conclusions The effect of the metallic additives (Al, Cr, and FeSi) on the properties of unfired periclase-carbon products was studied. It was shown that their presence decreases the degree of oxidation of graphite without decreasing the strength properties of the refractory. When heat treating the periclase-carbon specimens up to 1000°C, the effectiveness of the additives decreases in the following order: Al, Cr, FeSi. At 1400°C, the effectiveness of all the additives is virtually identical.Translated from Ogneupory, No. 8, pp. 7–9, August, 1989.     

Properties of refractories produced from synthetic magnesia

Conclusions The sinterability, open porosity, and cold-crushing strength of magnesite and magnesite-chromite specimens processed from magnesia powders (96–97% MgO) are improved with a decrease in the size of the periclase grains in the powder and with an increase in the firing temperature and do not depend on the percent and composition of the silicates and on the B₂O₃ content of the magnesia powder.The high-temperature bending strength of both types of refractories increases with a decrease in the B₂O₃ content of the magnesia powder. The creep resistance of the magnesite specimens increases with the ratio CaO/SiO₂ in the magnesia powder while the creep resistance of the magnesite — chromite specimens does not depend on this index.The indices of the open porosity and strength of the magnesite and magnesite — chromite specimens were optimal when they were produced with magnesia obtained by the bicarbonate method from dolomite.To produce dense and strong magnesite refractories from magnesia, they should be fired at a temperature not below 1700°C. The firing temperature of magnesite — chromite refractories should not be below 1750°C.Translated from Ogneupory, No. 6, pp. 53–57, June, 1978.     

变芯径光学纤维的性能与应用

变芯径光学纤维不同于现有的普通圆柱形光纤,它是沿长度方向芯径呈线性变化的圆锥形光纤.作为一种新型光纤,可增加光的耦合效率,汇聚输出光的能量,提高系统的稳定性和灵活性,可广泛应用在大功率激光传输、动态位置传感、荧光检测、数据存贮、图象传感等领域,其应用潜力极大.本文简述了变芯径光纤的产品性能及其在一些领域中的实际应用.     

MgO-CaO-ZrO2耐火材料的性能、制备与应用

系统地介绍了MgO-CaO-ZrO2耐火材料的性能特点、应用领域、制备与使用情况.指出,利用高纯原料制备MgO-CaO-ZrO2耐火材料已取得成功,而利用天然原料低成本地制备MgO-CaO-ZrO2耐火材料将成为今后研究的主要课题;同时指出,MgO-CaO-ZrO2耐火材料的剥落现象是影响其使用寿命的主要原因,还有待于进一步研究改进.     

六方氮化硼复合氧化铝耐火材料的性能研究

以粒度为3~1和≤1 mm的板状刚玉为骨料,板状刚玉细粉、α-Al2O3微粉和Si粉为细粉,分别添加质量分数为3%的六方氮化硼、3%和10%的鳞片石墨制备了Al2O3-BN和低碳、高碳Al2O3-C三种试样,并对比了其常温物理性能、高温强度、抗氧化性、抗热震性和抗渣侵蚀性。结果表明:1)Al2O3-BN耐火材料的常温、高温物理性能与低碳铝碳材料相差不大,并优于传统高碳铝碳材料;2)Al2O3-BN耐火材料具有比碳复合耐火材料更好的抗热震性和抗氧化性,抗渣性与低碳铝碳材料的相当;3)考虑到材料的整体性能,六方氮化硼可以替代石墨作为原料,用于制备综合性能优异的氧化铝质复合耐火材料。     

酚醛树脂-CarboresP结合镁碳材料的性能与应用

研究了环境友好型含碳材料CarboresP在镁碳砖中的应用。采用MT14A镁碳砖生产工艺,改变CarboresP的加入量,对试样180℃处理后的体积密度、高温抗折强度(1400℃),以及1000℃埋炭处理后的显气孔率、耐压强度等指标进行了研究和对比,确定镁碳砖中合适的CarboresP添加量为1%,并且可适量降低金属防氧化剂的加入量;分析了酚醛树脂-CarboresP结合炭的显微结构,表明其为均质炭和非均质石墨化炭的混合结构,这将有助于改善炭化结构的抗氧化性能;采用尖劈试验绘制镁碳砖试样的应力-应变曲线,表明添加CarboresP的镁碳砖的特征长度LCH值得到明显提高,说明它具有很好的韧性和吸收应力的能力;与传统工艺生产的MT14A镁碳砖相比较,采用酚醛树脂-CarboresP“软性结合”工艺生产的MT14A镁碳砖,成型性能及热处理后各项性能指标均得到改善,在国内某40tLF-VD精炼钢包渣线上进行现场使用证明,平均使用寿命比现用渣线镁碳砖提高18.4%。     

Properties of fired dolomite refractories with tar bond

Conclusions The laboratory specimens made of tar-bonded fired dolomite showed an apparent porosity of 8 to 18%; slightly better porosity was shown by specimens made with more fully sintered dolomite.The tar barely permeates the dolomite grains.When they are stored, the porosity is increased and the bulk density and strength of the specimens are reduced. This is less obvious after coke firing.Bricks made of all the tested dolomites with the addition of 8 and 6% tar at a pressure of 500 kg/cm² showed a bulk density of 2.6 g/cm² or more. Similar results are obtained when making the bricks by pneumatic tamping.For tests in the lining of converters we recommend blocks made of freshly fired dolomite with an apparent porosity of 5–10 and 15–20 and a grain composition lower than 15–10 mm. As a bond, 6 to 8% tar containing 65–70% medium coaltar pitch and 35–30% anthracite oil should be added. The blocks have to be pressed at at least 500 kg/cm².     

聚硅酸锌絮凝剂的性质与用途

介绍了聚硅酸锌絮凝剂的性质及其在制糖工业，饮用水处理和工业废水处理等方面的应用，说明聚硅酸锌絮凝剂对水和工业废水的处理效果优于传统的絮凝剂，具有絮凝颗粒大而实，沉降速度快，污泥含水率低，出水水质清，质量好，可以循环使用等优点。     

Properties of lime and lime-periclase refractories on a ceramic binder

Lime specimens obtained by clinker technology from sintered lime clinker with a relative density exceeding 75% of the theoretical value using TiO₂ as a sintering addition are investigated. It is established that the heat resistance of lime specimens is 25 heat cycles without fracture and the loss of strength after 20 – 25 heat cycles is insignificant. Posthydration investigation of the degradation of the strength of specimens has shown that the critical hydration level is 2%, after which the strength begins to fall sharply.Translated from Ogneupory, No. 2, pp. 2 – 5, February, 1995.     

Increasing the number of uses of the refractories in the slide gates of large steel-teeming ladles

Conclusions A method of enrichment of brucite by washing and sorting of it was developed. An experimental lot of composite slide gate plates for two teemings from the 300-ton steel teeming ladles of Magnitogorsk Metallurgical Combine was prepared from enriched fused brucite at Magnesite Combine. The physicochemical indices of the plates were 97.9 wt.% magnesium oxide with a nonequiaxiality of the periclase crystals of 1.94, 0.3% silica, 0.2% iron oxide, compressive strength 110 N/mm², and open porosity 12%. Under conditions of repeated openings and closings the plates made it possible to provide 100% quality teeming of the first heat and to direct 60% of the slide gates to repeated teeming, which was done with 32%. For a final experimental verification it would be desirable to prepare a larger experimental production lot of refractories using the method developed with specific repeated use.Translated from Ogneupory, No. 2, pp. 47–51, February, 1988.     

Properties and uses of some unsaturated fatty alcohols and their derivatives

A number of unsaturated fatty alcohols are known, but only those of the C₁₆ and C₁₈ chain lengths are of much importance. In particular, oleyl alcohol., 9,10-octadecenol-1, is by far the most important. A variety of grades of oleyl alcohols is produced and used in the USA ranging from high purity material having iodine values (IV) of 90–95 to those having IV of 45–55, with the other components being primarily cetyl (hexadecanol-1) and stearyl (octadecanol-1) alcohols. This paper takes a brief look at the various grades of unsaturated alcohols used in the USA, methods of preparation, and the change in physical and chemical properties as the octadecanol-1 content and IV decline. Uses of these alcohols industrially and in cosmetic and pharmaceutical preparations are also discussed. Unsaturated alcohols are useful chemical intermediates since they have two reactive sites, the hydroxyl group and the carbon-carbon double bond. Particular attention is paid to the properties, uses and potential uses of some of their sulfates, ether sulfates, ethylene oxide adducts and ethylene/propylene oxide adducts as detergents and emulsifiers for ultimate use in cosmetics and light-duty and heavy-duty systems. Current estimated consumption of unsaturated alcohols in the USA is discussed.