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An in-depth study has been carried out on the reduction, softening and melting behavior of olivine based pellets in the experimental blast furnace. The aim of the project was to develop a fundamental understanding of the reduction mechanisms of olivine based pellets and to develop a correlation between the reduction rate and the softening behavior in the cohesive zone of blast furnace. The carburization characteristics of reduced iron were also investigated by examining olivine pellet and coke samples excavated and probed from an experimental blast furnace as well as the experimental investigations of pure hematite and heat treated coke. X-ray diffraction analysis was used to successfully determine the reduction degree of olivine pellets in different parts of the experimental blast furnace. These results were found to be consistent with assessments of reduction degree based on a detailed chemical analysis. The average reduction degree of iron oxide was seen to increase as the pellets descended towards lower zones of the EBF. Up to 75% reduction was completed before the pellet had reached the cohesive zone; remaining reduction was completed within the cohesive zone. Coke Lc showed a linear variation with experimental temperature above 11000C; a correlation was established to estimate furnace temperature as a function of EBF depth. The reduction degree of iron ore pellet showed a linear correlation with distance from the stock line of the EBF to the upper part of cohesive zone. But an abrupt increase in reduction rate was observed in the cohesive zone, a result observed in both EBF and experimental studies. The presence of olivine did not have much influence on the reduction degree of iron ore pellets for temperatures below 1100oC in the upper shaft zone of the EBF. However, olivine was found to increase the rate of reduction in the advanced stages of reduction in the cohesive zone for temperatures in excess of 1100oC. This effect was attributed to the formation of increased amount of molten iron oxide within the pellet. The initial melt formation and acceleration of the reduction rate in the cohesive zone of the EBF were also investigated. From the comparison between the reduction degree of excavated olivine pellets in this study and previous studies of EBF, it was found that the excavated pellets were located in the cohesive zone and increase of reduction rate in this zone could be verified by not only the change of gas composition, but also initial melt formation containing FeO phase. The chemical composition of slag phases of excavated pellet samples were located on the line between 2FeO??SiO2 and 2MgO??SiO2 in the FeO-MgO-SiO2 ternary phase diagram. This result is in good agreement with the assumption that the initial slag formation of the olivine pellets had proceeded from the fayalite and after reduction the FeO contents in the slag phase had decreased and eventually precipitated as slag with a higher melting point. From the analysis of carbon contents of the excavated pellets in cohesive zone, it was observed that the carburization of iron pellets began after the complete reduction. This study has established that the reduction rate of iron pellet is the rate controlling step for carburization irrespective of the carburization reaction by the solid carbon.

An in-depth study has been carried out on the reduction, softening and melting behavior of olivine based pellets in the experimental blast furnace. The aim of the project was to develop a fundamental understanding of the reduction mechanisms of olivine based pellets and to develop a correlation between the reduction rate and the softening behavior in the cohesive zone of blast furnace. The carburization characteristics of reduced iron were also investigated by examining olivine pellet and coke samples excavated and probed from an experimental blast furnace as well as the experimental investigations of pure hematite and heat treated coke. X-ray diffraction analysis was used to successfully determine the reduction degree of olivine pellets in different parts of the experimental blast furnace. These results were found to be consistent with assessments of reduction degree based on a detailed chemical analysis. The average reduction degree of iron oxide was seen to increase as the pellets descended towards lower zones of the EBF. Up to 75% reduction was completed before the pellet had reached the cohesive zone; remaining reduction was completed within the cohesive zone. Coke Lc showed a linear variation with experimental temperature above 11000C; a correlation was established to estimate furnace temperature as a function of EBF depth. The reduction degree of iron ore pellet showed a linear correlation with distance from the stock line of the EBF to the upper part of cohesive zone. But an abrupt increase in reduction rate was observed in the cohesive zone, a result observed in both EBF and experimental studies. The presence of olivine did not have much influence on the reduction degree of iron ore pellets for temperatures below 1100oC in the upper shaft zone of the EBF. However, olivine was found to increase the rate of reduction in the advanced stages of reduction in the cohesive zone for temperatures in excess of 1100oC. This effect was attributed to the formation of increased amount of molten iron oxide within the pellet. The initial melt formation and acceleration of the reduction rate in the cohesive zone of the EBF were also investigated. From the comparison between the reduction degree of excavated olivine pellets in this study and previous studies of EBF, it was found that the excavated pellets were located in the cohesive zone and increase of reduction rate in this zone could be verified by not only the change of gas composition, but also initial melt formation containing FeO phase. The chemical composition of slag phases of excavated pellet samples were located on the line between 2FeO??SiO2 and 2MgO??SiO2 in the FeO-MgO-SiO2 ternary phase diagram. This result is in good agreement with the assumption that the initial slag formation of the olivine pellets had proceeded from the fayalite and after reduction the FeO contents in the slag phase had decreased and eventually precipitated as slag with a higher melting point. From the analysis of carbon contents of the excavated pellets in cohesive zone, it was observed that the carburization of iron pellets began after the complete reduction. This study has established that the reduction rate of iron pellet is the rate controlling step for carburization irrespective of the carburization reaction by the solid carbon.

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Dynamic modeling is proposed in this paper as a method of developing a computer model to simulate a water softening treatment unit. Information on water softening economics and ion exchange are examined. The development of a dynamic model is oriented toward uniform effluent water quality and operational flexibility. Several methods are presented to determine the reaction rate used in the completely mixed flow reactor's dynamic model. Based on preliminary data the proposed dynamic model would calculate removal rate similar to those found in an existing plant.

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The aim of this work was to visualise heterogeneous deformation in snow under controlled laboratory conditions. Heterogeneous deformation was observed for both homogenous and heterogeneous loading conditions. Understanding deformation of snow is important in many scientific fields including vehicle traction, avalanche forecasting, and winter sports. This thesis investigates the deformation behaviour of snow on the centimetre scale under moderate strain rates (0.005 to 0.1 s-1) when subject to one-dimensional compression or to indentation. In order to allow controlled and repeatable snow deformation experiments, a new type of artificial snow was developed. This snow type was examined by low temperature scanning electron microscopy and by traditional avalanche observer’s methodology. Penetrometer experiments were conducted on the artificial snow and on natural seasonal snow in Scotland. The two snow types were found to be similar: results obtained on artificial snow are thus applicable to natural snow. A reproducible technique of manufacture and a thorough characterisation of the artificial snow are presented. One-dimensional compression experiments were conducted on the artificial snow. The experiments were in confined compression in a specially constructed apparatus, designed to provide for back-lit photography. Images were taken at 0.25 second intervals and analysed using digital image correlation, thus providing 2D strain fields. With careful control of photographic parameters, it is demonstrated that process of applying tracer substances to the snow is not necessary, thus allowing an unprecedented resolution. Spontaneously-forming strain localisations were observed for the first time, indicating strain softening behaviour. Damage was observed to propagate through the specimen as a moving front, resembling a wave. The force required to propagate the front remained nearly constant until the whole specimen was compacted, at which point a new front formed and the process repeated. The experimental method was extended to 2D indention experiments with a range of sizes and shapes of indenter. Complex deformation fields were observed, extending up to 6 times the width of the indenter on each side. Observed deformation included tensile tearing as well as compression and shear. The maximum local strain achieved in the indentation experiments was similar to that achieved by the first compaction front in one-dimensional compression. The work here presented has implications for snow deformation generally: strain localisation introduces a characteristic length, which may prevent scaling of models or results. The indentation results are particularly relevant to snow penetrometry, where indentation experiments are used to try and extract microstructural information from buried snow layers for the purpose of avalanche prediction. The common assumption that the penetrometer interacts only with snow very close to its tip may need to be reconsidered.