A large number of studies have shown that oolitic hematite is an iron ore that is extremely difficult to utilize because of its fine disseminated particle size,high harmful impurity content and oolitic structure.To re...A large number of studies have shown that oolitic hematite is an iron ore that is extremely difficult to utilize because of its fine disseminated particle size,high harmful impurity content and oolitic structure.To recover iron from oolitic hematite,we developed a novel multistage dynamic magnetizing roasting technology.Compared with traditional magnetizing roasting technologies,this novel technology has the following advantages:firstly,the oolitic hematite is dynamically reduced in a multi-stage roasting furnace,which shortens the reduction time and avoids ringing and over-reduction;secondly,the novel dynamic magnetizing roasting technology has strong raw material adaptability,and the size range of raw materials can be as wide as 0–15 mm;thirdly,the roasting furnace adopts a preheating-heating process,and the low-calorific value blast furnace gas can be used as the fuel and reductant,which greatly reduces the cost.The actual industrial production data showed that the energy consumption in the roasting process can be less than 35 kg of standard coal per ton of raw ore.The iron grade of the concentrate and iron recovery reached 65%and 90%,respectively.展开更多
Niobium pentoxide(Nb_(2)O_(5))anodes have gained increasing attentions for high-power lithium-ion batteries owing to the outstanding rate capability and high safety.However,Nb2O5 anode suffers poor cycle stability eve...Niobium pentoxide(Nb_(2)O_(5))anodes have gained increasing attentions for high-power lithium-ion batteries owing to the outstanding rate capability and high safety.However,Nb2O5 anode suffers poor cycle stability even after modified and the unrevealed mechanisms have restricted the practical applications.Herein,the over-reduction of Nb5+has been demonstrated to be the critical reason for the capacity loss for the first time.Besides,an effective competitive redox strategy has been developed to solve the rapid capacity decay of Nb_(2)O_(5),which can be achieved by the incorporation of vanadium to form a new rutile VNbO_(4)anode.The highly reversible V^(3+)/V^(2+)redox couple in VNbO_(4)can effectively inhibit the over-reduction of Nb^(5+).Besides,the electron migration from V^(3+)to Nb5+can greatly increase the intrinsic electronic conductivity for VNbO4.As a result,VNbO4 anode delivers a high capacity of 206.1 mAh g^(−1)at 0.1 A g^(−1),as well as remarkable cycle performance with a retention of 93.4%after 2000 cycles at 1.0 A g^(−1).In addition,the assembled lithium-ion capacitor demonstrates a high energy density of 44 Wh kg^(−1)at 5.8 kW kg^(−1).In summary,our work provides a new insight into the design of ultra-fast and durable anodes.展开更多
基金National Natural Science Foundation of China(No.51974204)。
文摘A large number of studies have shown that oolitic hematite is an iron ore that is extremely difficult to utilize because of its fine disseminated particle size,high harmful impurity content and oolitic structure.To recover iron from oolitic hematite,we developed a novel multistage dynamic magnetizing roasting technology.Compared with traditional magnetizing roasting technologies,this novel technology has the following advantages:firstly,the oolitic hematite is dynamically reduced in a multi-stage roasting furnace,which shortens the reduction time and avoids ringing and over-reduction;secondly,the novel dynamic magnetizing roasting technology has strong raw material adaptability,and the size range of raw materials can be as wide as 0–15 mm;thirdly,the roasting furnace adopts a preheating-heating process,and the low-calorific value blast furnace gas can be used as the fuel and reductant,which greatly reduces the cost.The actual industrial production data showed that the energy consumption in the roasting process can be less than 35 kg of standard coal per ton of raw ore.The iron grade of the concentrate and iron recovery reached 65%and 90%,respectively.
基金support from National Natural Science Foundation of China(51874142)Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2019TQ05L903)Young Elite Scientists Sponsorship Program by CAST(2019QNRC001).
文摘Niobium pentoxide(Nb_(2)O_(5))anodes have gained increasing attentions for high-power lithium-ion batteries owing to the outstanding rate capability and high safety.However,Nb2O5 anode suffers poor cycle stability even after modified and the unrevealed mechanisms have restricted the practical applications.Herein,the over-reduction of Nb5+has been demonstrated to be the critical reason for the capacity loss for the first time.Besides,an effective competitive redox strategy has been developed to solve the rapid capacity decay of Nb_(2)O_(5),which can be achieved by the incorporation of vanadium to form a new rutile VNbO_(4)anode.The highly reversible V^(3+)/V^(2+)redox couple in VNbO_(4)can effectively inhibit the over-reduction of Nb^(5+).Besides,the electron migration from V^(3+)to Nb5+can greatly increase the intrinsic electronic conductivity for VNbO4.As a result,VNbO4 anode delivers a high capacity of 206.1 mAh g^(−1)at 0.1 A g^(−1),as well as remarkable cycle performance with a retention of 93.4%after 2000 cycles at 1.0 A g^(−1).In addition,the assembled lithium-ion capacitor demonstrates a high energy density of 44 Wh kg^(−1)at 5.8 kW kg^(−1).In summary,our work provides a new insight into the design of ultra-fast and durable anodes.
