Presently,ilmenite concentrates from Odisha Sands Complex at Chhatrapur,India are utilized to produce TiO2 slag by direct smelting in an electric arc furnace.However,the process involves the consumption of excess elec...Presently,ilmenite concentrates from Odisha Sands Complex at Chhatrapur,India are utilized to produce TiO2 slag by direct smelting in an electric arc furnace.However,the process involves the consumption of excess electrical energy and difficulty in handling the arc furnace due to frothing effects.A more efficient process of pre-reducing the ilmenite before smelting has been proposed in the present communication.In particular,studies have been undertaken on the reduction process of ilmenite-coke composite pellets.The difference in the reduction behaviour of raw ilmenite and ilmenite-coke composite pellets has been established and compared with that of the pre-oxidized raw pellets.The effects of various processing parameters like temperature,residence time,and reductant percentage on the metallization of composite pellets in a static bed have been investigated.Metallization of about 90%has been achieved at 1250°C for a reduction period of 360 min with a 4%coke composition.Furthermore,the reduced pellets have been characterized through chemical analysis,optical microscopy,field emission scanning electron microscopy and X-ray diffraction analysis.The reduction behaviour of composite pellets has also been found better than that of pre-oxidized pellets indicating the former to be more efficient.展开更多
The effects of pre-compression and pre-aging on the age-hardening response and microstructure of Mg-9.8Sn3.0 Zn(wt.%)alloy have been investigated via hardness test and advanced electron microscopy.The alloy subjected ...The effects of pre-compression and pre-aging on the age-hardening response and microstructure of Mg-9.8Sn3.0 Zn(wt.%)alloy have been investigated via hardness test and advanced electron microscopy.The alloy subjected to both pre-compression and pre-aging exhibits the most refined and densest distribution of precipitates upon aging at 200℃,leading to the superior age-hardening performance observed in the alloy.Comparatively,the alloy that underwent only pre-aging displayed a greater number density of precipitates than its counterpart that was neither pre-compressed nor pre-aged when both were aged to their peak conditions at 200℃,indicating an enhanced age-hardening response in the pre-aged alloy.The precipitates in these three peak-aged alloys consist of Mg_(2)Sn and MgZn_(2)phases.The reason why the pre-aged alloy has a higher number density of precipitates than the directly aged alloy is that MgZn_(2)phase formed during pre-aging can serve as heterogeneous nucleation site for the formation of Mg_(2)Sn.The reason why the pre compression and pre-aged alloy has the highest number density of precipitates is that Mg_(3)Sn and MgZn_(2)phases formed during pre-aging,alongside lattice defects introduced during pre-compression,collectively act as effective heterogeneous nucleation sites for the formation of Mg_(2)Sn during the subsequent aging at 200℃.展开更多
基金Project(MLP-52)supported by the Council of Scientific and Industrial Research(CSIR),India。
文摘Presently,ilmenite concentrates from Odisha Sands Complex at Chhatrapur,India are utilized to produce TiO2 slag by direct smelting in an electric arc furnace.However,the process involves the consumption of excess electrical energy and difficulty in handling the arc furnace due to frothing effects.A more efficient process of pre-reducing the ilmenite before smelting has been proposed in the present communication.In particular,studies have been undertaken on the reduction process of ilmenite-coke composite pellets.The difference in the reduction behaviour of raw ilmenite and ilmenite-coke composite pellets has been established and compared with that of the pre-oxidized raw pellets.The effects of various processing parameters like temperature,residence time,and reductant percentage on the metallization of composite pellets in a static bed have been investigated.Metallization of about 90%has been achieved at 1250°C for a reduction period of 360 min with a 4%coke composition.Furthermore,the reduced pellets have been characterized through chemical analysis,optical microscopy,field emission scanning electron microscopy and X-ray diffraction analysis.The reduction behaviour of composite pellets has also been found better than that of pre-oxidized pellets indicating the former to be more efficient.
基金Project(52101167)supported by the National Natural Science Foundation of ChinaProject(2022JJ40604)supported by the Natural Science Foundation of Hunan Province,ChinaProject(2022ZZTS0538)supported by the Postgraduate Research Innovation Project of Central South University,China。
文摘The effects of pre-compression and pre-aging on the age-hardening response and microstructure of Mg-9.8Sn3.0 Zn(wt.%)alloy have been investigated via hardness test and advanced electron microscopy.The alloy subjected to both pre-compression and pre-aging exhibits the most refined and densest distribution of precipitates upon aging at 200℃,leading to the superior age-hardening performance observed in the alloy.Comparatively,the alloy that underwent only pre-aging displayed a greater number density of precipitates than its counterpart that was neither pre-compressed nor pre-aged when both were aged to their peak conditions at 200℃,indicating an enhanced age-hardening response in the pre-aged alloy.The precipitates in these three peak-aged alloys consist of Mg_(2)Sn and MgZn_(2)phases.The reason why the pre-aged alloy has a higher number density of precipitates than the directly aged alloy is that MgZn_(2)phase formed during pre-aging can serve as heterogeneous nucleation site for the formation of Mg_(2)Sn.The reason why the pre compression and pre-aged alloy has the highest number density of precipitates is that Mg_(3)Sn and MgZn_(2)phases formed during pre-aging,alongside lattice defects introduced during pre-compression,collectively act as effective heterogeneous nucleation sites for the formation of Mg_(2)Sn during the subsequent aging at 200℃.
