Showing papers in "Transactions of The Indian Ceramic Society in 1971"
TL;DR: In this paper, a literature survey regarding zircon has been carried out covering the period upto 1970, which is organized into several chapters dealing with occurrence and beneficiation, crystal structure and morphology, the binary system ZrO2-SiO2, synthesis and dissociation of Zircon with and without added impurities, thermal properties, metamictization, uses for refractory, glass, enamel, glaze, pigment, porcelain, paint, foundry and other purposes.
Abstract: A literature survey regarding zircon has been carried out covering the period upto 1970. The material is organized into several chapters dealing with occurrence and beneficiation, crystal structure and morphology, the binary system ZrO2-SiO2, synthesis and dissociation of zircon with and without added impurities, thermal properties, metamictization, uses for refractory, glass, enamel, glaze, pigment, porcelain, paint, foundry and other purposes, and ternary systems in which the binary system ZrO2-SiO2 is a part.
8 citations
TL;DR: In this paper, the crystal structure of thorium silicate has been studied and a detailed theoretical calculation of the intensity has been done and the positions of the atoms have been assigned.
Abstract: Thorium silicate has been prepared during the course of hydrolysis of thorium salt solution at 180° C in sealed pyrex glass tubes. An attempt has been made to study the crystal structure of this substance. The system belongs to tetragonal system with space group: D194h—I4/amd. The values of ao and co are 7.00 and 6.32 in angstrom respectively. A detailed theoretical calculation of the intensity has been done and the positions of the atoms have been assigned.
4 citations
TL;DR: In this article, the effect of H-kaolinite on the pH of a dilute suspension of a H-montmorillonite has been studied and the nature of their interaction was examined in relation to their lattice structure and surface property.
Abstract: The effect of H-kaolinite on the pH of a dilute suspension of H-montmorillonite has been studied and the nature of their interaction was examined in relation to their lattice structure and surface property A small but gradual decrease of pH of the H-montmorillonite suspension was observed up to 18% addition of H-kaolinite beyond which the pH increases rapidly The titration behaviour is similar to that of HCl-H-clay system H-kaolinite was found to interact with H-montmorillonite due to the electrostatic attraction between the positive and negative sites of H-kaolinite and H-montmorillonite respectively The interaction appears to be independent of the structural peculiarity of the clay particles but related to their surface area
3 citations
3 citations
TL;DR: In this paper, the authors measured the vapour pressure of stoichiometric CsBO2 in the temperature range 898-1361° K and pseudo-vapour pressure over cesium tetrasilicate and borosilicate.
Abstract: Volatilisation loss of cesium from glass melts and from glass batches containing cesium nitrate has been reported Transpiration vapour pressure measurement of stoichiometric CsBO2 in the temperature range 898–1361° K and pseudo-vapour pressure of cesium over cesium silicate and cesium borosilicate in the temperature range 1323–1423° K have been determined Cesium metaborate has a vapour pressure of the order of 10−2 atmosphere at 1361° K whereas cesium vapour pressures over cesium tetrasilicate and cesium borosilicate are of the order of 10−5 atmosphere Cesium vapour pressure over cesium borosilicate is about 3 times higher at 1150° C than the corresponding pressure of cesium silicate Heat and entropy of evaporation for the reaction CsBO2 (l) ⇌ CsBO2 (v) have been found to be 4138 ± 4 Kcal/mole and 235 eu respectivelyThe reaction between CsNO3 and SiO2 or B2O3 is rapid and is accompanied with evolution of NO2 fumes Rapid reaction between CsNO3 starts at about 680° C and is complete within 15 minu
2 citations
TL;DR: In this article, a body of 95% alumina, 3.75% silica and 1.25% magnesia was sintered to a 98% theoretical density at a temperature of 1500°C.
Abstract: High alumina bodies of near theoretical density are necessary for many high temperature applications. Methods of preparation of such bodies (greater than 95% alumina content) at moderate sintering temperatures and the influence of liquid phase on the sintering behaviour of bodies in the magnesia low end of the MgO-Al2O3-SiO2 system have been studied. It was possible to sinter a body of 95% alumina, 3.75% silica and 1.25% magnesia to a 98%, theoretical density at a temperature of 1500°C.
2 citations
TL;DR: In this article, the technique of washing barium titanate calcines with hot water was used to obtain consistent dielectric properties. But the results showed that the results can be improved further by repeated calcination and prolonged grinding.
Abstract: There is a wide variation in the dielectric properties of barium titanate bodies, generally attributed to the changes in the BaO: TiO2 ratio and the presence of phases other than barium titanate. By incorporating the technique of washing barium titanate calcines with hot water it was found that bodies with consistent dielectric properties can be prepared. Improvement in properties can be achieved further by repeated calcination and prolonged grinding.
2 citations
TL;DR: In this paper, the effect of humic acids on the agglomerate structures of kaolinite and montmorillonite particles as well as their natural mixture in dilute H-clay suspension has been studied.
Abstract: The effect of humic acids on the agglomerate structures of kaolinite and montmorillonite particles as well as their natural mixture in dilute H-clay suspension has been studied. It has been observed that humic acids even when added in small proportion in H-kaolinite suspension, the agglomeration of the particles disappear and they remain in dispersed state. No such effect is observed either in montmorillonite or in mixture of kaolinite and montmorillonite suspension where particles also exist in agglormerated form. A possible mechanism has been suggested to explain their behaviour with humic acids.
1 citations
TL;DR: In this paper, the equilibrium between octahedral and tetrahedral cobalt (II) has been studied in H2O-HCl, HCl-O4-HCL, HCL-KCNS solutions and CaO-B2O3-Al 2O3 glasses.
Abstract: The equilibrium between octahedral and tetrahedral cobalt (II) has been studied in H2O- HCl, H2O-HClO4-HCl, H2O-KCNS solutions and in R2O-B2O3, R2O-SiO2, R2O-Al2O3-SiO2, and CaO- B2O3-Al2O3 glasses. In aqueous solution, cobalt (II) absorption, in the region 10 to 25 kK, increases with increased addition of HCl or KCNS. In R2O-B2O3 and R2O-SiO2 glasses absorption of cobalt (II) increases with increased addition of R2O. In R2O-Al2O3-SiO2 and CaO-B2O3-Al2O3 glasses the total absorption area and the relative area of the resolved band around 15 kK (characteristic of tetrahedral cobalt (II) decrease with increased substitution of Al2O3 for SiO2 or B2O3. However, in CaO-B2O3-Al2O3 glasses containing a high proportion of Al2O3 and CaO, the octahedral-tetrahedral equilibrium of cobalt (II) behaved differently.In all the systems of solutions and glasses the total absorption area from 10 to 25 kK or the relative area of the resolved band around 15 kK (4A2)(F) → 4T1(P) could be used as a qualitative measure of the oc...
1 citations
TL;DR: In this article, the coagulation behavior of binary H-clay mixtures of kaolinite and montmorillonite in dilute suspension has been studied in the presence of various cations.
Abstract: Coagulation behaviour of binary H-clay mixtures of kaolinite and montmorillonite in dilute suspension has been studied in the presence of various cations. It has been observed that the coagulation and charge reversal characteristics of one clay constituent is modified by the other in presence of electrolytes. The extent of modification depends upon the nature and proportion of each electrolyte and on the composition of the mixture. The coagulating power as well as charge reversal capacity of cations increases in the following way: Th+4> > H+ > Ca+2 > Na+. An attempt has been made to explain these characteristics.
1 citations
TL;DR: In this article, the suitability of Indian lepidolite as a flux for the development of semi-vitreous and vitreous bodies at comparatively low temperatures was investigated.
Abstract: A study has been made of the suitability of Indian lepidolite as a flux for the development of semi-vitreous and vitreous bodies at comparatively low temperaturesSubstitution of felspar by lepidolite not only reduced the maturing temperature but appreciably increased the mechanical strength and maturing range This improvement was all the more pronounced with increasing flux content A combination of lepidolite, felspar and talc was found to be ideally suited for the development of vitreous and semi-vitreous bodies at temperatures lying between cone 01 and 2 and having a firing range good enough for commercial firing There was however, no appreciable effect on thermal expansion
TL;DR: In this article, thermal studies on Pyrophyllite Diaspore Minerals were carried out in the Indian Ceramic Society (ICS.30, No. 2, pp 68-71).
Abstract: (1971). Thermal Studies on Pyrophyllite Diaspore Minerals. Transactions of the Indian Ceramic Society: Vol. 30, No. 2, pp. 68-71.
TL;DR: In this paper, three sets of UO2-ThO2 mixtures, varying in their powder characteristics, were sintered between 1250°c and 1550°C for different soaking periods.
Abstract: The literature survey on sintering of binary oxide systems like UO2-ThO2 shows a vast difference of opinion on the effect of composition on sintering of mixtures. Three sets of UO2-ThO2 mixtures, varying in their powder characteristics, were sintered between 1250°C and 1550°C for different soaking periods.The results are explained on the basis of a proposed concept of sintering. This concept, seems to adequately explain the large variations in the sintering behaviour of such oxides., reported in this work as well as in the work of earlier authors.
TL;DR: In this paper, the formation of solid solution during sintering treatment has a significant effect on the densification behavior of the oxide mixtures and the influence of temperature and composition on the solid solution formation was studied.
Abstract: UO2 and ThO2 are known to form a continuous series of solid solutions over the entire range of composition. The formation of solid solution during the sintering treatment has a significant effect on the densification behaviour of the oxide mixtures. Attempts were made to study the solid solution formation in this system by X-ray diffraction technique.The influence of temperature and composition on the solid solution formation was studied. An indication of the role of diffusion in material movement was obtained by tracing the progress of solid solution formation with change in the heat treatment. Lattice parameters of UO2-ThO2 solid solutions were also determined.
TL;DR: In this article, the hydraulicity of synthetic slags with fixed lime and varying SiO2 and Al2O3 ratio was studied in relation to their crystallization.
Abstract: Hydraulicity of synthetic slags with fixed lime and varying SiO2 and Al2O3 ratio was studied in relation to their crystallization. Slags with low Al2O3 content produced improved hydraulicity on low temperature heat treatment. Slags with higher Al2O3content, which were almost non-hydraulic in the glassy state, showed better hydraulicity on crystallization.
TL;DR: An apparatus for continuous classification of abrasive powders into various pre- determined particle size groups (grits) is described in this article, where the conventional method of using water has been modified to incorporate an agitation zone and a separation zone in the body of the elutriator.
Abstract: An apparatus for continuous classification of abrasive powders into various pre determined particle size groups (grits) is described. The conventional method of e/utria tion (using water) has been modified to incorporate an agitation zone and a separation zone in the body of the elutriator. The effect of velocity of water, degree of agitation, rate of through-put (feed rate of solids), pulp density and the height of elutriation column on the particle size distribution and yield of the product, have been studied.
TL;DR: In this paper, the authors reviewed some of the latest developments in the refractory construction and other improvements incorporated in the blast furnaces of the Tata Iron & Steel Company, including the sinter in the burden, increasing hot blast temperature, etc.
Abstract: During the last two decades, several developments have taken place in the field of iron production. Necessary design changes were made in the blast furnaces to suit the demands. The furnaces are driven harder for increased productivity by incorporating the sinter in the burden, increasing the hot blast temperature, etc. These improvements in the field of metallurgy naturally demand better refractories and construction methods. This article reviews some of the latest developments in the refractory construction and other improvements incorporated in the blast furnaces of the Tata Iron & Steel Company.
TL;DR: In this article, high density uranium dioxide pellets prepared by sintering at 1500° C were refired at 1800°, 1900° and 2000°C, and the electrical conductivity of the samples varied considerably showing a minima at a refiring temperature of 1900°C.
Abstract: As reported earlier, electrical conductivity of sintered uranium dioxide pellets depended on the calcination temperature and the sintering treatments, and could be related to the microstructure attained. The highest sintering temperature studied was 1700° C. In the present study, high density pellets prepared by sintering at 1500° C were refired at 1800°, 1900° and 2000°C. Though there were no significant changes in the densities, the electrical conductivity of the samples varied considerably showing a minima at a refiring temperature of 1900°C. Attempts were made to correlate the changes in electrical conductivity to the microstructural changes which still seem to be influenced by the thermal history of the samples.
TL;DR: In this article, dielectric measurements on six different glasses have been made at room temperatures between the frequency range 105 and 3 × 107 cycles per second by resonance technique, and a peculiar loss peak has been observed in one case which has been suggested to be due to vibration of a large group of ions having a resonant frequency much lower than the frequency of vibration of individual ions.
Abstract: Dielectric measurements on six different glasses have been made at room temperatures between the frequency range 105 and 3 × 107 cycles per second by resonance technique. A peculiar loss peak has been observed in one case which has been suggested to be due to vibration of a large group of ions having a resonant frequency much lower than the frequency of vibration of individual ions.