SPLITTING OF SOFT-MUD BRICK*

A study was made of the cause and methods of preventing the splitting of Hudson River soft-mud brick. The splitting occurred in the kiln and paralleled the 8- by 4-in face of the brick and was found to be associated with black coring. Tests made on various portions of the brick showed that the black portions were more vitreous and had lower thermal expansions than the outer, more oxidized portions. On cooling, the stresses resulting from the difference in thermal expansion were such as to tend to split the brick Modification of brick mixes and method of setting are recommended to overcome black coring.     

EFFECT OF THE SULFATE ION ON THE PLASTICITY OF BRICK CLAYS*

Two red-firing Iowa brick clays were analyzed for sulfate (SO₄⁻) content by a method suitable for plant-control tests. From this datum the amount of barium carbonate required to react with this ion can be calculated. Plasticity measurements on (1) samples treated with the amount of barium carbonate indicated by SO₄⁻ analysis, (2) untreated samples, and (3) samples treated with normal plant additions show significant differences in this property. These differences can be explained using the modern concepts of the factors which influence the zeta potential.     

成型方式对石英砂烧结砖性能的影响研究

利用低品位石英砂制备高性能石英砂烧结砖,通过对原料和砖体物相分析、砖体的显微结构分析以及砖体的物理性能分析,研究了成型方式对砖体性能的影响。结果表明:等静压成型的压力比手压成型的大得多,使得坯体内部气孔数量少且孔径小,有利烧结。等静压成型所制备的砖体抗压强度(34.8MPa)比可塑(手压)成型的砖体抗压强度(19.5MPa)高得多,但与烧结砖的国家标准相比,两种成型方式的烧结砖各种性能都达到标准。     

EFFECT OF MOLTEN ALUMINUM ON VARIOUS REFRACTORY BRICK*

To study the effect of molten aluminum on refractory brick with a view toward explaining some of the brick failures in aluminum melting furnaces, the following test was conducted. Brick of different compositions and from various manufacturers were placed on end in the bottom of an electrically heated ladle to which molten aluminum was added. After holding the molten aluminum in contact with the brick for thirty-five days, it was poured out and the ladle was allowed to cool slowly to room temperature. A study of the brick revealed that some failed by penetration of the aluminum into the brick accompanied by a reaction between the aluminum and the brick. This penetration was less with the denser brick than with the more porous ones. Of the brick tested, there was the least reaction between aluminum and the chrome brick and most between aluminum and silica brick. Many other factors, however, must be considered when deciding which brick is the most economical to use in aluminum melting.     

AN INVESTIGATION OF THE ACTION OF COAL-ASH SLAGS ON FIRE BRICK BY MICROSCOPIC METHODS*

The action of coal-ash slags on firebrick refractories was studied by microscopic examination of thin sections prepared from quenched samples of ash and refractory heated together. The eight refractories used varied as to clays, method of fabrication, grind, and firing treatment. Six different coal ashes varied from highly corrosive to noncorrosive ashes. Samples were quenched at intervals in the range of 2200 to 2800°F and the critical temperature or maximum safe operating temperature of all combinations of slag and refractory was determined. These values are presented together with a discussion of the various minerals formed.     

等静压成型压力对石英砂烧结砖性能的影响研究

利用低品位石英砂制备高性能石英砂烧结砖,通过对原料和砖体物相分析、砖体的显微结构分析以及砖体的物理性能分析,研究等静压成型压力对砖体性能的影响.结果表明:随着成型压力的增加,砖体的烧结温度逐步降低至最低点然后升高,其中65MPa成型的砖体比100MPa成型的砖体的烧结温度要高15℃.砖体的抗压强度随着成型压力的增大,先升高后降低,其中在100MPa等静压成型所制备的砖体抗压强度达到35.1MPa,与烧结砖的国家标准相比,性能达烧结普通砖的国家最高标准MU30级.     

INVESTIGATION OF THE EFFECT OF HEAT ON THE CLAY MINERALS ILLITE AND MONTMORILLONITE*

Samples of three purified illites, one purified montmorillonite, and one natural clay containing montmorillonite, quartz, and limonite were heated at successive temperatures up to 1400°C. X-ray and optical determinations were made on all samples. The changes that take place in the clay minerals, illite and montmorillonite, when they are heated at various temperatures up to 1400°C. are discussed.     

DISINTEGRATING EFFECT OF REPEATED FREEZING AND THAWING ON BUILDING BRICK*

Laboratory freezing and thawing tests (A.S.T.M. test No. C47–44 and modifications thereof) were correlated with results of outdoor-exposure tests. This correlation was based on saturation coefficient, absorption, rate of absorption, strength, and method of manufacture. New York building brick of the soft-mud and stiff-mud types were investigated. The results show that those brick within a specific absorption range and with the greatest strength and the smallest saturation coefficient will have lower loss in the freezing-thawing tests.     

EFFECT OF COMPOSITION ON PROPERTIES OF TITANIUM ENAMELS*

The development of a superopaque, acid-resistant titanium enamel is described. Different components of the batch were varied systematically and the properties, such as reflectance, color, flow, gloss, and acid resistance, were determined. Variations in composition, reflectance curves, and spectrophotometer curves are given for all of the enamels investigated. The stability of this type of enamel during firing and smelting was also studied. Spectrophotometric analyses of this type of enamel show a characteristic low reflectance in the short-wave length region of the visible spectrum, differing in this respect from superopaque antimony and zirconia enamels. Additions of as much as 0.5% Fe₂O₃ and 0.2% V₂O₅ to the titanium enamel did not cause any appreciable variations in color. Although some differences in the spectrophotometer curves were noted over the field of enamels investigated, the only major change in color occurred when minute amounts of Cr₂O₃ were present. X-ray diffraction patterns of enamels show that rutile crystals in most cases, or sometimes anatase, are the crystals causing opacity.     

PRELIMINARY INVESTIGATION ON THE EFFECT OF FOAM STABILIZERS ON THE PHYSICAL CHARACTERISTICS AND RECONSTITUTION PROPERTIES OF FOAM-MAT DRIED SOYMILK

Soymilk, a colloidal dispersion obtained by wet milling of soya bean (Glycine max (L) Merill), was subjected to the foam-mat drying process at 65°C using two foam stabilizers namely, carboxy methyl cellulose (CMC) and glyceryl distearate (GDS) at 5, 10 and 15% levels. While CMC did not produce a stable foam at any of the levels used, it was however, found that a minimum of 10% GDS was required to produce a stable foam. The physical characteristics and reconstitution properties of 10% GDS foamed soymilk powder and 15% GDS foamed soymilk powder were found to be similar but better than those of unfoamed soymilk powder and inferior to those of a spray dried powder sample.     

PRELIMINARY INVESTIGATION ON THE EFFECT OF FOAM STABILIZERS ON THE PHYSICAL CHARACTERISTICS AND RECONSTITUTION PROPERTIES OF FOAM-MAT DRIED SOYMILK

Soymilk, a colloidal dispersion obtained by wet milling of soya bean (Glycine max (L) Merill), was subjected to the foam-mat drying process at 65°C using two foam stabilizers namely, carboxy methyl cellulose (CMC) and glyceryl distearate (GDS) at 5, 10 and 15% levels. While CMC did not produce a stable foam at any of the levels used, it was however, found that a minimum of 10% GDS was required to produce a stable foam. The physical characteristics and reconstitution properties of 10% GDS foamed soymilk powder and 15% GDS foamed soymilk powder were found to be similar but better than those of unfoamed soymilk powder and inferior to those of a spray dried powder sample.     

活性稀释剂种类对环氧树脂体系性能的影响研究

采用丁基缩水甘油醚(660)、乙二醇二缩水甘油醚(669)和苯基缩水甘油醚(690)三种活性稀释剂对环氧树脂/甲基四氢邻苯二甲酸酐(MeTHPA)固化体系进行改性,研究了稀释剂对树脂胶液粘度及其固化物力学性能和电性能的影响。结果表明,当加入669和690稀释剂后,体系的介电性能基本不变,耐电弧性能提高,而660的加入会降低体系的介质损耗,对耐电弧性能影响很小。其中,当690的添加量为3%时,耐电弧达到94s,比纯树脂提高了22%;当添加量为3%～12%时,树脂固化物的拉伸强度稳定在45～55MPa之间。     

EFFECT OF EXCHANGEABLE BASES ON TORSION PROPERTIES OF CLAYS*

Torsion properties of a plastic fire clay, a ball clay, two flint fire clays, a bentonite, and Georgia kaolin were studied. The effect of exchangeable bases on the surface of the clay particles on stress-strain relationships was established. The widest differences, in general, were found in the sodium and hydrogen forms of the various bodies. A rational explanation of the behavior of clays with different exchangeable bases lies in the fact that their colloidal natures govern to a large degree their workable characteristics, and colloidal properties, in turn, are dependent on the water film surrounding the particle. The nature of the water film is influenced by the kind and the nature of the charges in the ion atmosphere surrounding the particles and may be changed by replacing an exchangeable base with another cation.     

ZrO2—Al2O3系浆料性能的研究

本文研究了加入高分子电解质——聚丙烯酸(PAA),对于pH值在中性范围内ZrO_2-H_2O、Al_2O_3-H_2O系统的流变和动电特性的影响。根据胶体化学基础知识,利用计算机对实验数据进行分析、处理并设计实验。讨论了PAA在氧化物表面的吸附机理及其饱和吸附量,找到了一种确定ZrO_2-Al_2O_3双组分浆料稳定悬浮条件的新方法。     

EFFECT OF ZINC OXIDE ON SHEET-IRON COVER-ENAMEL PROPERTIES*

The effect of ZnO on sheet-iron cover-enamel properties was studied by evaluation of the properties of a typical sheet-iron cover enamel in which ZnO was used as single- and double-partial replacements for the various ingredients. The fluxing action of ZnO was found to be pronounced and it was markedly effective in decreasing frit solubility in the mill liquor. Improvement in gloss resulted from its use without any adverse effect on enamel extensibility and resistance to thermal shock.     

CORRELATION OF ELECTRICAL AND THERMAL PROPERTIES OF BUILDING BRICK *

A relationship has been found to exist between the electrical and thermal conductivities of certain ceramic materials. This relation appears to be both a direct and an approximately linear function of the porosity of the material and, for the materials used, independent of chemical composition. Current-voltage relations bear out the generally accepted assumption that solid, non-metallic dielectrics, such as ceramic materials, exhibit electrical conductivity by virtue of a movement of ions. Current-time’relations indicate that the materials used in this study exhibited an appreciable polarization current, the magnitude and time of decay of which were closely associated with the porosity. The latter, time of decay, is of particular interest. From these observations, it is evident that the effective direct-current resistance of a ceramic insulator may not be its final steady-state resistance but some much lower value.     

锅炉飞灰燃烧特性实验研究

锅炉飞灰中含碳量高不但导致了锅炉燃烧效率的降低,也限制了飞灰的再利用。因此,降低飞灰含碳量,充分利用其化学能,具有较高的经济价值,对石家庄东方热点公司锅炉飞灰的粒径分布、烧失量分级分布和燃烧特性进行了研究。结果表明,通过飞灰再燃可以有效地降低飞灰中的含碳量,并在实验室小型鼓泡流化床上进行了飞灰再燃降低含碳量的验证实验。     

EFFECT OF ADDITIONS OF DIOPSIDE ON PROPERTIES OF WALL-TILE BODY *

Diopside was substituted for both talc and feldspar in a typical wall-tile body. It was found to lower the fusion temperature and to lower thermal expansion when compared with talc and to raise thermal expansion when compared with feldspar. Its effects on firing shrinkage, fired absorption, and moisture expansion were somewhat similar to those of talc.