Burnt lime and serpentine were incorporated into the sinter mix to improve high iron and low silica sinte-ring. Optimization of how to use burnt lime including dosage of burnt lime, moisture of sinter mix, hydrating a...Burnt lime and serpentine were incorporated into the sinter mix to improve high iron and low silica sinte-ring. Optimization of how to use burnt lime including dosage of burnt lime, moisture of sinter mix, hydrating andgranulation time was performed. Evaluations of sinter characteristics including sinter mineralogy, reducibility, lowtemperature reduction degradation, softening and melting down properties were carried out. Compared with the re-sults of traditional process in base case, the tumbling index (TI) is increased by 1.53%-2.33% through proportio-ning high ratio of burnt lime or adding serpentine in the sinter mix. It is shown that effective granulation, better per-meability and improved high temperature reactivity in the sinter bed are achieved, resulting in an increase in 3.13 %- 5.10% calcium ferrite occurring in acicular and columnar shape and decrease in glass phase, and with the reduc-ibility index(RI) being increased by 1.65%- 3.25%.展开更多
A great amount of red mud generated from alumina production by Bayer process not only threatens the environment but also causes waste of secondary resources.High-iron-content red mud from Bayer process was employed to...A great amount of red mud generated from alumina production by Bayer process not only threatens the environment but also causes waste of secondary resources.High-iron-content red mud from Bayer process was employed to recover alumina and ferric oxide by the process of reduction-sintering,leaching and then magnetic beneficiation.Results of thermodynamic analyses show that ferric oxide should be reduced to Fe if reduction of ferric oxide and formation of sodium aluminate and calcium silicate happen simultaneously.Experimental results indicate that alumina recovery of Bayer red mud can reach 89.71%,and Fe recovery rate and the grade of magnetite concentrate are 60.67%and 61.78%,respectively,under the optimized sintering conditions.展开更多
A new method of utilizing high-silica hematite to produce low-silicon molten iron was proposed.In this method,FASTMELT,which comprised direct reduction and melt separation processes,was applied,with highly reactive bi...A new method of utilizing high-silica hematite to produce low-silicon molten iron was proposed.In this method,FASTMELT,which comprised direct reduction and melt separation processes,was applied,with highly reactive biochar as the reductant in the direct reduction stage.The proposed method was experimentally investigated and the results show that the method is feasible.In the direct reduction stage,ore-char briquette could achieve a metallization rate of 84%-88% and residual carbon of 0.27-0.89mass% at temperature of 1373 K,biochar mixing ratio of 0.8-0.9,and reduction time of 15 min.Some silica particles remained embedded in the iron phase after the reduction.In the melting separation stage,molten iron with a carbon content of 0.02-0.03mass% and silicon content of 0.02-0.18mass%could be obtained from the metallic briquettes under the above-mentioned conditions;the iron recovery rate was83%-91% and impurities in the obtained metal were negligible.展开更多
FeCe nanocomposite catalysts with different iron contents were synthesized by a facile co-precipitation method.The as-prepared materials were characterized by various techniques including powder X-ray diffraction(XRD)...FeCe nanocomposite catalysts with different iron contents were synthesized by a facile co-precipitation method.The as-prepared materials were characterized by various techniques including powder X-ray diffraction(XRD),N2 adsorption/desorption and high-resolution transmission electron microscopy(HRTEM).Catalyst with the highest iron content(90 FeCe) shows the best activity for the hydrogen generation via ammonia decomposition.83% NH3 conversion is achieved at 550℃ and nearly full conversion of NH3 is realized at 600℃ with a GHSV of 24000 cm3/(gcat·h).The large content and small size crystal particles of iron species are responsible for the good catalytic performance.Temperatureprogrammed reduction by hydrogen(H2-TPR) was performed to investigate the interaction between cerium and iron species.It is found that slight cerium can exert strong interaction with iron compound thus effectively prevent the self-aggregation of active iron species,so as to improve the catalytic activity for ammonia decomposition.展开更多
基金Project(2000-26) supported by the Foundation for the Teaching and Research Program for Outstanding Young Teachers in Higher Education Institutions of Education Ministry, China
文摘Burnt lime and serpentine were incorporated into the sinter mix to improve high iron and low silica sinte-ring. Optimization of how to use burnt lime including dosage of burnt lime, moisture of sinter mix, hydrating andgranulation time was performed. Evaluations of sinter characteristics including sinter mineralogy, reducibility, lowtemperature reduction degradation, softening and melting down properties were carried out. Compared with the re-sults of traditional process in base case, the tumbling index (TI) is increased by 1.53%-2.33% through proportio-ning high ratio of burnt lime or adding serpentine in the sinter mix. It is shown that effective granulation, better per-meability and improved high temperature reactivity in the sinter bed are achieved, resulting in an increase in 3.13 %- 5.10% calcium ferrite occurring in acicular and columnar shape and decrease in glass phase, and with the reduc-ibility index(RI) being increased by 1.65%- 3.25%.
基金Project(2005CB623702)supported by the National Basic Research Program of China
文摘A great amount of red mud generated from alumina production by Bayer process not only threatens the environment but also causes waste of secondary resources.High-iron-content red mud from Bayer process was employed to recover alumina and ferric oxide by the process of reduction-sintering,leaching and then magnetic beneficiation.Results of thermodynamic analyses show that ferric oxide should be reduced to Fe if reduction of ferric oxide and formation of sodium aluminate and calcium silicate happen simultaneously.Experimental results indicate that alumina recovery of Bayer red mud can reach 89.71%,and Fe recovery rate and the grade of magnetite concentrate are 60.67%and 61.78%,respectively,under the optimized sintering conditions.
基金the National Natural Science Foundation of China(Grant No.51144010)for the financial support
文摘A new method of utilizing high-silica hematite to produce low-silicon molten iron was proposed.In this method,FASTMELT,which comprised direct reduction and melt separation processes,was applied,with highly reactive biochar as the reductant in the direct reduction stage.The proposed method was experimentally investigated and the results show that the method is feasible.In the direct reduction stage,ore-char briquette could achieve a metallization rate of 84%-88% and residual carbon of 0.27-0.89mass% at temperature of 1373 K,biochar mixing ratio of 0.8-0.9,and reduction time of 15 min.Some silica particles remained embedded in the iron phase after the reduction.In the melting separation stage,molten iron with a carbon content of 0.02-0.03mass% and silicon content of 0.02-0.18mass%could be obtained from the metallic briquettes under the above-mentioned conditions;the iron recovery rate was83%-91% and impurities in the obtained metal were negligible.
基金Project supported by the Natural Science Foundation of Jiangsu Province (BK20170232,BK20170238)National Natural Science Foundation of China (51908256)。
文摘FeCe nanocomposite catalysts with different iron contents were synthesized by a facile co-precipitation method.The as-prepared materials were characterized by various techniques including powder X-ray diffraction(XRD),N2 adsorption/desorption and high-resolution transmission electron microscopy(HRTEM).Catalyst with the highest iron content(90 FeCe) shows the best activity for the hydrogen generation via ammonia decomposition.83% NH3 conversion is achieved at 550℃ and nearly full conversion of NH3 is realized at 600℃ with a GHSV of 24000 cm3/(gcat·h).The large content and small size crystal particles of iron species are responsible for the good catalytic performance.Temperatureprogrammed reduction by hydrogen(H2-TPR) was performed to investigate the interaction between cerium and iron species.It is found that slight cerium can exert strong interaction with iron compound thus effectively prevent the self-aggregation of active iron species,so as to improve the catalytic activity for ammonia decomposition.
