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Papers by Samir Ganguly
ISIJ International, 2010
Reduction of MnO from slag and wetting of carbonaceous materials were studied in reaction of synt... more Reduction of MnO from slag and wetting of carbonaceous materials were studied in reaction of synthetic and industrial ferromanganese slags with graphite and coke substrates by the sessile drop method at 1 450-1 550°C. Reduced metal was found at slag-substrate interface and at gas-slag-substrate boundary of slag perimeter. The reduced metal was mainly manganese with small amount of dissolved silicon and carbon. The reduction rate of MnO increased with increasing activity of MnO in slag and temperature. The rate of MnO reduction from industrial slag was faster than from the synthetic slag; slag was more reactive with coke substrate than with graphite substrate. The reduction rate was observed to increase with increasing ash content in the substrate. The dynamic contact angle between carbon substrate and slag varied in a range of 80°to 140°and it decreased in the process of reaction. Lower contact angle was observed for a substrate with higher ash content.
ISIJ International, 2003
This paper examines the reduction of pure MnO, Groote Eylandt (Northern Australia) manganese ore,... more This paper examines the reduction of pure MnO, Groote Eylandt (Northern Australia) manganese ore, siliceous manganese fines and ferromanganese slag by graphite. Reduction was conducted in the stagnant atmosphere of argon, Ar-CO gas of varying composition and helium. The rate and extent of reduction were determined by thermo-gravimetric analysis and by monitoring CO and CO 2 concentrations in the gas phase. The rate of MnO reduction in Ar-CO gas increased with decreasing CO partial pressure. Reduction in helium was faster than in argon. Under given experimental conditions (stagnant gas atmosphere) the reduction rate was mix-controlled by CO mass transfer in the gas phase and chemical reaction.
SYNOPSIS Carbothermal reduction of manganese oxides and manganese ores in the solid state was stu... more SYNOPSIS Carbothermal reduction of manganese oxides and manganese ores in the solid state was studied in hydrogen, helium and argon at different temperatures, ore compositions and carbon to manganese oxide ratios. Wessels ore (South Africa) and two grades of the Groote Eylandt ore (Australia) with different level of impurities were examined. Ores were characterised by XRD, X-ray fluorescence, optical microscopy
Metallurgical and Materials Transactions B Process Metallurgy and Materials Processing Science, Sep 30, 2008
Carbothermal reduction of manganese oxides was studied in hydrogen, helium, and argon at differen... more Carbothermal reduction of manganese oxides was studied in hydrogen, helium, and argon at different temperatures and carbon-to-manganese oxide ratios. Isothermal and temperature programmed carbothermal reduction experiments were conducted in a fixed bed reactor in a vertical tube furnace, with on-line monitoring of gas composition by the CO-CO 2 infrared sensor. The extent of reduction was calculated using the off-gas composition and LECO oxygen contents in the reduced samples. In all gas atmospheres, the reaction rate increased with temperature. The reduction rate of manganese oxide in hydrogen was higher than in helium, and in helium higher than in argon. This was attributed to the involvement of hydrogen in the reduction process and the difference in CO and CO 2 diffusion coefficients in helium and argon.
Steel Research International, 2006
ABSTRACT
ISIJ International, 2004
The paper presents results of reduction of pure manganese oxides by methane containing gas in non... more The paper presents results of reduction of pure manganese oxides by methane containing gas in nonisothermal and isothermal experiments and reduction mechanisms. The extent and rate of manganese oxide reduction were determined by on-line off-gas analysis using a mass-spectrometer in a fixed bed laboratory reactor in the temperature range 1 000-1 200°C at different gas compositions. Manganese oxides were reduced to carbide Mn 7 C 3. High extent and rate of reduction by methane-containing gas in comparison with carbothermal reduction were attributed to high carbon activity in the reducing gas, which was in the range 15-50 (relative to graphite). The rate of reduction of manganese oxide increased with increasing temperature. Increasing methane content in the reducing gas to 10-20 vol% CH 4 favoured the reduction process. Increase in hydrogen partial pressure had a positive effect on the reduction rate. Addition of carbon monoxide to the reducing gas retarded the reduction process. The addition of Fe 3 O 4 to manganese oxide increased the rate of reduction. Reduction by methane-containing gas occurs through adsorption and cracking of methane with formation of active adsorbed carbon. Deposition of solid carbon retarded the reduction.
ISIJ International, 2010
Reduction of MnO from slag and wetting of carbonaceous materials were studied in reaction of synt... more Reduction of MnO from slag and wetting of carbonaceous materials were studied in reaction of synthetic and industrial ferromanganese slags with graphite and coke substrates by the sessile drop method at 1 450-1 550°C. Reduced metal was found at slag-substrate interface and at gas-slag-substrate boundary of slag perimeter. The reduced metal was mainly manganese with small amount of dissolved silicon and carbon. The reduction rate of MnO increased with increasing activity of MnO in slag and temperature. The rate of MnO reduction from industrial slag was faster than from the synthetic slag; slag was more reactive with coke substrate than with graphite substrate. The reduction rate was observed to increase with increasing ash content in the substrate. The dynamic contact angle between carbon substrate and slag varied in a range of 80°to 140°and it decreased in the process of reaction. Lower contact angle was observed for a substrate with higher ash content.
ISIJ International, 2003
This paper examines the reduction of pure MnO, Groote Eylandt (Northern Australia) manganese ore,... more This paper examines the reduction of pure MnO, Groote Eylandt (Northern Australia) manganese ore, siliceous manganese fines and ferromanganese slag by graphite. Reduction was conducted in the stagnant atmosphere of argon, Ar-CO gas of varying composition and helium. The rate and extent of reduction were determined by thermo-gravimetric analysis and by monitoring CO and CO 2 concentrations in the gas phase. The rate of MnO reduction in Ar-CO gas increased with decreasing CO partial pressure. Reduction in helium was faster than in argon. Under given experimental conditions (stagnant gas atmosphere) the reduction rate was mix-controlled by CO mass transfer in the gas phase and chemical reaction.
SYNOPSIS Carbothermal reduction of manganese oxides and manganese ores in the solid state was stu... more SYNOPSIS Carbothermal reduction of manganese oxides and manganese ores in the solid state was studied in hydrogen, helium and argon at different temperatures, ore compositions and carbon to manganese oxide ratios. Wessels ore (South Africa) and two grades of the Groote Eylandt ore (Australia) with different level of impurities were examined. Ores were characterised by XRD, X-ray fluorescence, optical microscopy
Metallurgical and Materials Transactions B Process Metallurgy and Materials Processing Science, Sep 30, 2008
Carbothermal reduction of manganese oxides was studied in hydrogen, helium, and argon at differen... more Carbothermal reduction of manganese oxides was studied in hydrogen, helium, and argon at different temperatures and carbon-to-manganese oxide ratios. Isothermal and temperature programmed carbothermal reduction experiments were conducted in a fixed bed reactor in a vertical tube furnace, with on-line monitoring of gas composition by the CO-CO 2 infrared sensor. The extent of reduction was calculated using the off-gas composition and LECO oxygen contents in the reduced samples. In all gas atmospheres, the reaction rate increased with temperature. The reduction rate of manganese oxide in hydrogen was higher than in helium, and in helium higher than in argon. This was attributed to the involvement of hydrogen in the reduction process and the difference in CO and CO 2 diffusion coefficients in helium and argon.
Steel Research International, 2006
ABSTRACT
ISIJ International, 2004
The paper presents results of reduction of pure manganese oxides by methane containing gas in non... more The paper presents results of reduction of pure manganese oxides by methane containing gas in nonisothermal and isothermal experiments and reduction mechanisms. The extent and rate of manganese oxide reduction were determined by on-line off-gas analysis using a mass-spectrometer in a fixed bed laboratory reactor in the temperature range 1 000-1 200°C at different gas compositions. Manganese oxides were reduced to carbide Mn 7 C 3. High extent and rate of reduction by methane-containing gas in comparison with carbothermal reduction were attributed to high carbon activity in the reducing gas, which was in the range 15-50 (relative to graphite). The rate of reduction of manganese oxide increased with increasing temperature. Increasing methane content in the reducing gas to 10-20 vol% CH 4 favoured the reduction process. Increase in hydrogen partial pressure had a positive effect on the reduction rate. Addition of carbon monoxide to the reducing gas retarded the reduction process. The addition of Fe 3 O 4 to manganese oxide increased the rate of reduction. Reduction by methane-containing gas occurs through adsorption and cracking of methane with formation of active adsorbed carbon. Deposition of solid carbon retarded the reduction.