Rare earth elements(REE)include the lanthanide series elements(La,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Dy.Ho,Er,Tm,Yb,and Lu)plus Sc and Y.Currently these metals have become very critical to several modern technologies ranging fro...Rare earth elements(REE)include the lanthanide series elements(La,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Dy.Ho,Er,Tm,Yb,and Lu)plus Sc and Y.Currently these metals have become very critical to several modern technologies ranging from cell phones and televisions to LED light bulbs and wind turbines.This article summarizes the occurrence of these metals in the Earth’s crust,their mineralogy,different types of deposits both on land and oceans from the standpoint of the new data with more examples from the Indian subcontinent.In addition to their utility to understand the formation of the major Earth reservoirs.multi-faceted updates on the applications of REE in agriculture and medicine including new emerging ones are presented.Environmental hazards including human health issues due to REE mining and large-scale dumping of e-waste containing significant concentrations of REE are summarized.New strategies for the future supply of REE including recent developments in the extraction of REE from coal fired ash and recycling from e-waste are presented.Recent developments in individual REE separation technologies in both metallurgical and recycling operations have been highlighted.An outline of the analytical methods for their precise and accurate determinations required in all these studies,such as,Xray fluorescence spectrometry(XRF),laser induced breakdown spectroscopy(LIBS),instrumental neutron activation analysis(INAA),inductively coupled plasma optical emission spectrometry(ICP-OES),glow discharge mass spectrometry(GD-MS),inductively coupled plasma mass spectrometry(including ICP-MS,ICP-TOF-MS,HR-ICP-MS with laser ablation as well as solution nebulization)and other instrumental techniques,in different types of materials are presented.展开更多
Hydrogen metallurgy is a technology that applies hydrogen instead of carbon as a reduction agent to reduce CO2 emission,and the use of hydrogen is beneficial to promoting the sustainable development of the steel indus...Hydrogen metallurgy is a technology that applies hydrogen instead of carbon as a reduction agent to reduce CO2 emission,and the use of hydrogen is beneficial to promoting the sustainable development of the steel industry.Hydrogen metallurgy has numerous applications,such as H2reduction ironmaking in Japan,ULCORED and hydrogen-based steelmaking in Europe;hydrogen flash ironmaking technology in the US;HYBRIT in the Nordics;Midrex H2TM by Midrex Technologies,Inc.(United States);H2FUTURE by Voestalpine(Austria);and SALCOS by Salzgitter AG(Germany).Hydrogen-rich blast furnaces(BFs)with COG injection are common in China.Running BFs have been industrially tested by AnSteel,XuSteel,and BenSteel.In a currently under construction pilot plant of a coal gasification–gas-based shaft furnace with an annual output of 10000 t direct reduction iron(DRI),a reducing gas composed of 57 vol%H2 and 38 vol%CO is prepared via the Ende method.The life cycle of the coal gasification–gas-based shaft furnace–electric furnace short process(30 wt%DRI+70 wt%scrap)is assessed with 1 t of molten steel as a functional unit.This plant has a total energy consumption per ton of steel of 263.67 kg standard coal and a CO2 emission per ton of steel of 829.89 kg,which are superior to those of a traditional BF converter process.Considering domestic materials and fuels,hydrogen production and storage,and hydrogen reduction characteristics,we believe that a hydrogen-rich shaft furnace will be suitable in China.Hydrogen production and storage with an economic and large-scale industrialization will promote the further development of a full hydrogen shaft furnace.展开更多
The extraction of vanadium from high calcium vanadium slag was attempted by direct roasting and soda leaching. The oxidation process of the vanadium slag at different temperatures was investigated by X-ray diffraction...The extraction of vanadium from high calcium vanadium slag was attempted by direct roasting and soda leaching. The oxidation process of the vanadium slag at different temperatures was investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. The effects of roasting temperature, roasting time, Na2CO3 concentration, leaching tem- perature, leaching time, and liquid to solid ratio on the extraction of vanadium were studied. The results showed that olivine phases and spinel phases in the vanadium slag were completely decomposed at 500 and 800℃, respectively. Vanadium-rich phases were formed at above 850℃. The leaching rate of vanadium reached above 90% under the optimum conditions： roasting temperature of 850℃, roasting time of 60 min, Na2CO3 concentration of 160 g/L, leaching temperature of 95℃, leaching time of 150 min, and liquid to solid ratio of 10：1 mL/g. The main impurities were Si and P in the leach liquor.展开更多
The influence of roasting on the leaching rate and valence of vanadium was evaluated during vanadium extraction from stone coal. Vanadium in stone coal is hard to be leached and the leaching rate is less than 10% when...The influence of roasting on the leaching rate and valence of vanadium was evaluated during vanadium extraction from stone coal. Vanadium in stone coal is hard to be leached and the leaching rate is less than 10% when the raw ore is leached by 4 moUL H2SO4 at 90℃ for 2 h. After the sample is roasted at 900℃ for 2 h, the leaching rate of vanadium reaches the maximum, and more than 70% of vanadium can be leached. The crystal of vanadium-bearing mica minerals decomposes and the Content of V（V） increases with the rise of roasting temperature from 600 to 900℃, therefore the leaching rate of vanadium increases significantly with the decomposition of the mica minerals. Some new phases, anorthite for example, form when the roasting temperature reaches 1000℃. A part of vanadium may be enwrapped in the sintered materials and newly formed phases, which may impede the oxidation of low valent vanadium and make the leaching rate of vanadium drop dramatically. The leaching rate of vanadium is not only determined by the valence state of vanadium but also controlled by the decomposition of vanadium-bearing minerals and the existence state of vanadium to a large extent.展开更多
文摘Rare earth elements(REE)include the lanthanide series elements(La,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Dy.Ho,Er,Tm,Yb,and Lu)plus Sc and Y.Currently these metals have become very critical to several modern technologies ranging from cell phones and televisions to LED light bulbs and wind turbines.This article summarizes the occurrence of these metals in the Earth’s crust,their mineralogy,different types of deposits both on land and oceans from the standpoint of the new data with more examples from the Indian subcontinent.In addition to their utility to understand the formation of the major Earth reservoirs.multi-faceted updates on the applications of REE in agriculture and medicine including new emerging ones are presented.Environmental hazards including human health issues due to REE mining and large-scale dumping of e-waste containing significant concentrations of REE are summarized.New strategies for the future supply of REE including recent developments in the extraction of REE from coal fired ash and recycling from e-waste are presented.Recent developments in individual REE separation technologies in both metallurgical and recycling operations have been highlighted.An outline of the analytical methods for their precise and accurate determinations required in all these studies,such as,Xray fluorescence spectrometry(XRF),laser induced breakdown spectroscopy(LIBS),instrumental neutron activation analysis(INAA),inductively coupled plasma optical emission spectrometry(ICP-OES),glow discharge mass spectrometry(GD-MS),inductively coupled plasma mass spectrometry(including ICP-MS,ICP-TOF-MS,HR-ICP-MS with laser ablation as well as solution nebulization)and other instrumental techniques,in different types of materials are presented.
基金the National Natural Science Foundation of China(No.51904063)the Fundamental Research Funds for the Central Universities(Nos.N2025023,N172503016,N172502005,and N172506011)+1 种基金the China Postdoctoral Science Foundation(No.2018M640259)the Xingliao Talent Plan(No.XLYC1902118)。
文摘Hydrogen metallurgy is a technology that applies hydrogen instead of carbon as a reduction agent to reduce CO2 emission,and the use of hydrogen is beneficial to promoting the sustainable development of the steel industry.Hydrogen metallurgy has numerous applications,such as H2reduction ironmaking in Japan,ULCORED and hydrogen-based steelmaking in Europe;hydrogen flash ironmaking technology in the US;HYBRIT in the Nordics;Midrex H2TM by Midrex Technologies,Inc.(United States);H2FUTURE by Voestalpine(Austria);and SALCOS by Salzgitter AG(Germany).Hydrogen-rich blast furnaces(BFs)with COG injection are common in China.Running BFs have been industrially tested by AnSteel,XuSteel,and BenSteel.In a currently under construction pilot plant of a coal gasification–gas-based shaft furnace with an annual output of 10000 t direct reduction iron(DRI),a reducing gas composed of 57 vol%H2 and 38 vol%CO is prepared via the Ende method.The life cycle of the coal gasification–gas-based shaft furnace–electric furnace short process(30 wt%DRI+70 wt%scrap)is assessed with 1 t of molten steel as a functional unit.This plant has a total energy consumption per ton of steel of 263.67 kg standard coal and a CO2 emission per ton of steel of 829.89 kg,which are superior to those of a traditional BF converter process.Considering domestic materials and fuels,hydrogen production and storage,and hydrogen reduction characteristics,we believe that a hydrogen-rich shaft furnace will be suitable in China.Hydrogen production and storage with an economic and large-scale industrialization will promote the further development of a full hydrogen shaft furnace.
基金financially supported by the National High-Tech Research and Development Program of China (No. 2008AA031104)the National Basic Research and Development Program of China (No. 2007CB13503)the National Natural Science Foundation of China(No. 51090382)
文摘The extraction of vanadium from high calcium vanadium slag was attempted by direct roasting and soda leaching. The oxidation process of the vanadium slag at different temperatures was investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. The effects of roasting temperature, roasting time, Na2CO3 concentration, leaching tem- perature, leaching time, and liquid to solid ratio on the extraction of vanadium were studied. The results showed that olivine phases and spinel phases in the vanadium slag were completely decomposed at 500 and 800℃, respectively. Vanadium-rich phases were formed at above 850℃. The leaching rate of vanadium reached above 90% under the optimum conditions： roasting temperature of 850℃, roasting time of 60 min, Na2CO3 concentration of 160 g/L, leaching temperature of 95℃, leaching time of 150 min, and liquid to solid ratio of 10：1 mL/g. The main impurities were Si and P in the leach liquor.
基金financially supported by the National Key Technologies R&D Program of China(Nos.2011BAB05B01 and 2011BAB05B04)the Exclusive Research Fund of Environmental Protection for the Commonweal of China(No.201009013)
文摘The influence of roasting on the leaching rate and valence of vanadium was evaluated during vanadium extraction from stone coal. Vanadium in stone coal is hard to be leached and the leaching rate is less than 10% when the raw ore is leached by 4 moUL H2SO4 at 90℃ for 2 h. After the sample is roasted at 900℃ for 2 h, the leaching rate of vanadium reaches the maximum, and more than 70% of vanadium can be leached. The crystal of vanadium-bearing mica minerals decomposes and the Content of V（V） increases with the rise of roasting temperature from 600 to 900℃, therefore the leaching rate of vanadium increases significantly with the decomposition of the mica minerals. Some new phases, anorthite for example, form when the roasting temperature reaches 1000℃. A part of vanadium may be enwrapped in the sintered materials and newly formed phases, which may impede the oxidation of low valent vanadium and make the leaching rate of vanadium drop dramatically. The leaching rate of vanadium is not only determined by the valence state of vanadium but also controlled by the decomposition of vanadium-bearing minerals and the existence state of vanadium to a large extent.
