Showing papers in "Transactions of The Indian Ceramic Society in 1962"
TL;DR: The effects of different fluxing ingredients on melting characteristics, thermal expansion, DC resistivity and dielectric properties of the glass compositions, MgO 10, CaO10, Al2O3 19, SiO2 61% and Mg O 18, Al 2O319, Si O2 63% were studied in this paper.
Abstract: The effects of different fluxing ingredients on melting characteristics, thermal expansion, DC resistivity and dielectric properties of the glass compositions, MgO 10, CaO 10, Al2O3 19, SiO2 61% and MgO 18, Al2O3 19, SiO2, 63% were studied. Li2O is the strongest fluxing ingredient but it increased expansivity and dielectric loss. Addition of fluorine up to 3% and MnO up to 6% improved meltability without appreciably affecting thermal and electrical properties. B2O3, ZnO, BaO and TiO2 do not have such beneficial effects. Presence of even small amounts of alkalies (less than 1%) appreciably increased dielectric loss at high temperatures. Properties of these glasses compare well with those of some of the common insulating materials.
5 citations
TL;DR: The effect of impurities present in some natural magnesites on the sintering process and crystal growth of periclase at high temperatures, as well as the nature, and distribution of matrix minerals and pores in the sintered Magnesites have been examined by microscopic and X-ray diffraction studies as discussed by the authors.
Abstract: The effect of impurities present in some natural magnesites on the sintering process and crystal growth of periclase at high temperatures, as well as the nature, and distribution of matrix minerals and pores in the sintered magnesites have been examined by microscopic and X-ray diffraction studies.Iron oxide promotes sintering of magnesites and crystal growth of periclase. Lime does not adversely affect the sintering process, but has a definite retarding effect on the crystal growth of periclase at high temperatures. Sintering behaviour of magnesite rich in silica does not materially differ from that of a relatively pure magnesite but silica acts as a powerful crystal growth promoter for periclase.
4 citations
TL;DR: In this paper, chemical and physical properties of a sample of dead-burnt sea-water magnesia supplied by Messrs. Tata Chemicals, Mithapur, were studied with a view to utilise it for refractory purposes.
Abstract: Chemical and physical properties of a sample of dead-burnt sea-water magnesia supplied by Messrs. Tata Chemicals, Mithapur, were studied with a view to utilise it for refractory purposes. Though th...
3 citations
TL;DR: In this paper, the same SiO2/Al2O3 ratio was used to identify ettringite, tetracalcium aluminate hydrate, tobermorite and hydrogarnets.
Abstract: Slags of varying CaO content, having same SiO2/Al2O3 ratio were hydrated in presence of varying proportions of lime and mixtures of lime and gypsum for different periods. The hydrated materials were subjected to DTA. When slags were hydrated in presence of lime only there appeared tetracalcium aluminate hydrate in all cases. Tobermorite and hydrogarnets were also possibly formed. Absorption of lime was indicated in all cases. This decreased with increase of CaO1 in the slag and increased with time. When slags were hydrated in presence of lime and gypsum, the compounds identified were ettringite, crystalline solution of ‘low-sulfate’ aluminate sulfate double salt and tetracalcium aluminate hydrate. The former changed over to the latter when the proportion of gypsum in the mixture was low and lime in the mixture or CaO in the slag was high. Absorption of lime during hydration in presence of lime and gypsum was always more than in presence of lime only and this increased with acidity of slag and with time. A...
3 citations
TL;DR: The first Shanti Swarup Bhatnagar Memorial Lecture as discussed by the authors was delivered by the author on October 6, 1961, before the National Institute of Sciences, India.
Abstract: This is the first Shanti Swarup Bhatnagar Memorial Lecture delivered by the author on October 6, 1961, before the National Institute of Sciences, India. The author has given a thoughtful account of the development of the optical glass industry and in this he discovers the fundamental prerequisite for industrial progress namely, the close co-ordination among scientific thoughts, technological actions and industrial growth. This happened in different countries in the past, happened again in India in producing optical glass, and is the right step towards our technological independence.In view of the special appeal of the lecture to the workers in the fields of glass and ceramics, it is being reproduced here from the Proceedings of the National Institute of Sciences of India [27A (6) 1961], with the permission of the Institute.Editor
2 citations
TL;DR: The physical tiests, chemical analysis, DTA, X-ray analysis, base exchange study and refractoriness of the clay from Kumbalam (Kerala State) were carried out.
Abstract: The physical tiests, chemical analysis, DTA, X-ray analysis, base exchange study and refractoriness of the clay from Kumbalam (Kerala State) were carried out It has been found to be a good clay for refractory purpose
2 citations
TL;DR: In this article, the effect of heat on structural changes in kaolinite was studied by measuring density, loss in weight, linear shrinkage and moisture absorption of a 95% clay heated to different temperatures.
Abstract: The effect of heat on structural changes in kaolinite was studied by measuring density, loss in weight, linear shrinkage and moisture absorption of a 95% kaolinite clay heated to different temperatures. The results show that metakaoline is formed around 500°C, and it partially retains the structure of kaolinite. With further rise in temperature, the semblance of crystallinity is lost gradually and a new crystalline phase appears at about 850°C, as envisaged by Brindley and Nakahira.
2 citations
TL;DR: In this article, the Indian Standard method for testing alkalinity of glass was modified to improve the accuracy and rapidity of the method and the results obtained by the two methods show that the extracted glass constituents other than the alkalies did not have any effect on the titre value.
Abstract: The Indian Standard method for testing alkalinity of glass was modified to improve the accuracy and rapidity of the method. Ten commercial glasses having, widely different chemical durabilities were tested for alkalinity and the extracted amounts of alkalies were estimated flame photometrically as well as by titration. The results obtained by the two methods show that the extracted glass constituents other than the alkalies did not have any effect on the titre value.The same sampled were also tested according to the DIN method as proposed by the International Standards Organisation and the ratio of the titre values as obtained by the IS and DIN methods was found to be 0.55.
1 citations
TL;DR: In this article, two clays from Bansi, Mirzapur District, were studied for their suitability for refractory purposes and chemical and physical tests carried out on these clays reveal that they are refractor in nature and can be utilised for the manufacture of medium-heat-duty fire clay refractories.
Abstract: Samples of two clays from Bansi, Mirzapur District, were studied for their suitability for refractory purposes. One of the clays which was non-plastic appeared to be partially dehydrated in the natural state. Chemical and physical tests carried out on these two clays reveal that they are refractory in nature and can be utilised for the manufacture of medium-heat-duty fire clay refractories. These clays show a high porosity even when fired atl450°C. This property may be taken advantage of in making insulation refractories by suitable addition of combustible matter.
1 citations
TL;DR: In this paper, expansion during the curing of cements consisting of granulated blast furnace slag, lime and gypsum in different proportions was studied and the extent of interaction of reacting components was followed by DTA and measurement of degree of hydration and compressive strength.
Abstract: Expansion during curing of cements consisting of granulated blast furnace slag, lime and gypsum in different proportions was studied. The extent of interaction of reacting components was followed by DTA and measurement of degree of hydration and compressive strength. The amount of ettringite formed was found to determine expansion. Results indicated that the ettringite formed at first was accommodated in the pores and when the proportion of ettringite increased an expansive force was set up which increased with the increase of ettringite content. Presence of time and gypsum was found necessary for ettringite formation to continue.
1 citations
TL;DR: In this article, the authors obtained PbO-B2O3-SO3 and ZnO-BSO3 -SO3 clear and stable glasses containing upto 20 mole per cent SOs.
Abstract: In the systems PbO-B2O3-SO3 and ZnO-B2O3-SO3 clear and stable glasses containing upto about 20 mole per cent SOs were obtained. Unlike the borate glasses, thin films of sulphate-containing glasses show selective infra-red transmission around 12μ. Compared to the corresponding borate glasses, thermal expansion is higher. DC resistivity, dielectric constant and softening temperature do not change significantly by replacing B2O3 with SO3. Addition of SO3, improves resistance of lead glasses to water attack but deteriorates zinc glasses. Some of the glasses did not show any visible change after they were kept exposed to atmosphere for about a year.
TL;DR: In this paper, the regenerators of glass melting tank furnaces are discussed and some of the important considerations in designing regenerators and selecting the refractories for their constructions are discussed.
Abstract: Construction of the regenerators of glass melting tank furnaces needs careful thought to enable them to outlive the tank proper. Some of the important considerations in designing regenerators and selecting the refractories for their constructions are discussed here.