Advanced Materials and Processes Research Institute
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Electrochemical studies on the oxidation behaviour of iron in NaNO3-NaNO2 melt.
No full textThe oxidation behaviour of iron in NaNO3-NaNO2 melt has been studied by potentiodynamic polarisation and electrochemical noise measurements in the temperature range of 250–550°C. The open circuit potential and the repassivation potential shifted in a noble direction with temperature up to 450°C due to the formation of stable oxide film. An opposite effect was found at 550°C due to breakdown of the oxide film. An increase of noise power values with the increase of temperature was observed which indicated an increased diffusion of iron ions in the formation of oxide film. X-ray diffraction investigation of the surface film formed on iron showed the presence of a sodium ferrite layer on the iron surface. The oxidation rate obtained by the Tafel extrapolation method was in agreement with the harmonic current measurements. The activation energy of the process was 57.43 kJ mol−1.\u
Annual Progress Report of Regional Research Laboratory, Bhopal for 1993-1994
No full textAnnual Progress Report of Regional Research Laboratory, Bhopal for 1993-199
Determination of total phosphorus in rock phosphate minerals by a modified faster titrimetric method.
No full text
Mineralogical investigations on an Indian glauconitic sandstone of Madhya Pradesh state
No full textGlauconitic sandstone occurring in Majhgawan, Madhya Pradesh (India) was examined to study the composition and association of glauconite with different minerals. The study was carried out by petrographic investigation, X-ray powder diffraction (XRD), simultaneous thermal analyses (STA) and infrared (IR) spectral method. With a majority of quartz grains, glauconite pellets (both clear and limonitized) along with a smaller percentage of potash feldspars and mica minerals are found embedded in a mixed ferruginous and glauconitic matrix. The nature of (001), (020) and (003) spacings as found in the XRD patterns obtained for different fractions of the sample suggests the presence of disordered glauconite in the glauconitic sandstone. XRD identification is amply supported by endotherms at 560°C in differential thermal analysis (DTA) curves representing loss of constitutional water from the glauconite structure. Appearance of endotherms in DTA curves in the 275–353°C temperature range indicates the presence of poorly crystalline goethite, which is also substantiated by the absence of characterstic d lines of goethite in XRD patterns. On heating the sample to 760°C, (001) reflection of kaolinite disappears and further heating to 1000°C causes collapse of the glauconite structure also. Formation of hematite takes place in the sample heat-treated at 1000°C. The results demonstrate a clear rising trend of glauconite and kaolinite contents and diminishing proportions of quartz with the reduction in the particle size of the sample
Modelling of a 76 mm Diammeter Dense Medium Cyclone.
No full textModelling of a 76 mm diameter dense medium cyclone treating coal in the size range - 2·0 + 0·5 mm have been done on the basis of extensive experimental data generated. The behaviour of independent sizes such as 2·0+ 1·4,-1·4+1·18,- 1·18 + 1·0,- 1·0 + 0·6,-0·6+0·5 mm fractions within the size range of-2·0+ 0·5 mm were separately analysed. Mathematical relationships for the throughput of slurry, water distribution to the overflow and underflow have been developed. Three methods have been devised for the prediction of yield and ash content of the clean coal under different combinations of design parameters such as vortex finder and spigot diameter and the operating condition such as relative density of the magnetite medium. Generalised distribution curves of independent size fractions for the separation of coal using the distribution curves of coal of different size fractions have been mathematically represented. It was found that classification size of magnetite medium solids has effect on the relative density of separation of coal
