The demand for alternative low-grade iron ores is on the rise due to the rapid depletion of high-grade natural iron ore resources and the increased need for steel usage in daily life.However,the use of low-grade iron ...The demand for alternative low-grade iron ores is on the rise due to the rapid depletion of high-grade natural iron ore resources and the increased need for steel usage in daily life.However,the use of low-grade iron ores is a constant clinical task for industry metallurgists.Direct smelting of low-grade ores consumes a substantial amount of energy due to the large volume of slag generated.This condition can be avoided by direct reduction followed by magnetic separation(to separate the high amount of gangue or refractory and metal parts)and smelting.Chromite overburden(COB)is a mine waste generated in chromite ore processing,and it mainly consists of iron,chromium,and nickel(<1wt%).In the present work,the isothermal and non-isothermal kinetics of the solid-state reduction of self-reduced pellets prepared using low-grade iron ore(COB)were thoroughly investigated via thermal analysis.The results showed that the reduction of pellets followed a firstorder autocatalytic reaction control mechanism in the temperature range of 900-1100℃.The autocatalytic nature of the reduction reaction was due to the presence of nickel in the COB.The apparent activation energy obtained from the kinetics results showed that the solid-state reactions between COB and carbon were the rate-determining step in iron oxide reduction.展开更多
A novel isocratic reverse phase high performance liquid chromatography （RP-HPLC） with photo diode array （PDA） detection method for the determination of dobutamine （DBT） in rat plasma was developed and validated ...A novel isocratic reverse phase high performance liquid chromatography （RP-HPLC） with photo diode array （PDA） detection method for the determination of dobutamine （DBT） in rat plasma was developed and validated after optimization of various chromatographic conditions and other experimental parameters. Homoveratrylamiue was used as an internal standard. Methanol was used as the extracting solvent for the preparation of plasma samples. Samples were separated on a Symmetry C18 （250ram x4.6mm i.d., 5 pro） analytical column. Acetonitrile and 15raM potassium dihydrogen phosphate （pH 5.0 with 0.3% TEA） （20：80, v/v） was used. The column oven temperature was optimized at 35 ~C and the flow rate was 0.8 mL/min. The detection wavelength was fixed at 230 nm for entire analysis. The calibration curve was found to be linear over the concentration range of 50-2000 ng/mL （ra=0.9992）. The limit of quantification （LOQ） of the method was 50 ng/mL. The % RSD values of accuracy and precision values for intra and inter days were 〈 15% at quality control （QC） concentrations. Recovery, stability and robustness were studied within the acceptable range according to ICH guidelines. The method was efficiently applied to a pharmacokinetic study in healthy Wistar rats.展开更多
文摘The demand for alternative low-grade iron ores is on the rise due to the rapid depletion of high-grade natural iron ore resources and the increased need for steel usage in daily life.However,the use of low-grade iron ores is a constant clinical task for industry metallurgists.Direct smelting of low-grade ores consumes a substantial amount of energy due to the large volume of slag generated.This condition can be avoided by direct reduction followed by magnetic separation(to separate the high amount of gangue or refractory and metal parts)and smelting.Chromite overburden(COB)is a mine waste generated in chromite ore processing,and it mainly consists of iron,chromium,and nickel(<1wt%).In the present work,the isothermal and non-isothermal kinetics of the solid-state reduction of self-reduced pellets prepared using low-grade iron ore(COB)were thoroughly investigated via thermal analysis.The results showed that the reduction of pellets followed a firstorder autocatalytic reaction control mechanism in the temperature range of 900-1100℃.The autocatalytic nature of the reduction reaction was due to the presence of nickel in the COB.The apparent activation energy obtained from the kinetics results showed that the solid-state reactions between COB and carbon were the rate-determining step in iron oxide reduction.
基金Mr.Thippani Ramesh thanks MHRD,Government of India for providing financial assistance
文摘A novel isocratic reverse phase high performance liquid chromatography （RP-HPLC） with photo diode array （PDA） detection method for the determination of dobutamine （DBT） in rat plasma was developed and validated after optimization of various chromatographic conditions and other experimental parameters. Homoveratrylamiue was used as an internal standard. Methanol was used as the extracting solvent for the preparation of plasma samples. Samples were separated on a Symmetry C18 （250ram x4.6mm i.d., 5 pro） analytical column. Acetonitrile and 15raM potassium dihydrogen phosphate （pH 5.0 with 0.3% TEA） （20：80, v/v） was used. The column oven temperature was optimized at 35 ~C and the flow rate was 0.8 mL/min. The detection wavelength was fixed at 230 nm for entire analysis. The calibration curve was found to be linear over the concentration range of 50-2000 ng/mL （ra=0.9992）. The limit of quantification （LOQ） of the method was 50 ng/mL. The % RSD values of accuracy and precision values for intra and inter days were 〈 15% at quality control （QC） concentrations. Recovery, stability and robustness were studied within the acceptable range according to ICH guidelines. The method was efficiently applied to a pharmacokinetic study in healthy Wistar rats.
