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In situ formed Mg(BH_(4))_(2) for improving hydrolysis properties of MgH_(2)
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作者 Yongyang Zhu Mili Liu +6 位作者 liming Zeng Yin Wang Daifeng Wu Rui Li Qing Zhou Renheng Tang Fangming Xiao 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第3期1204-1214,共11页
The hydrolysis of MgH_(2) delivers high hydrogen capacity(15.2 wt%),which is very attractive for real-time hydrogen supply.However,the formation of a surface passivation Mg(OH)_(2) layer and the large excess of H_(2)O... The hydrolysis of MgH_(2) delivers high hydrogen capacity(15.2 wt%),which is very attractive for real-time hydrogen supply.However,the formation of a surface passivation Mg(OH)_(2) layer and the large excess of H_(2)O required to ensure complete hydrolysis are two key challenges for the MgH_(2) hydrolysis systems.Now,a low-cost method is reported to synthesize MgH_(2)@Mg(BH_(4))_(2) composite via ball-milling MgH_(2) with cheap and widely available B2O_(3)(or B(OH)3).By adding small amounts of B2O_(3),the in-situ formed Mg(BH_(4))_(2) could significantly promote the hydrolysis of MgH_(2).In particular,the MgH_(2)–10 wt%B2O_(3) composite releases 1330.7 mL·g^(−1) H_(2)(close to 80%theoretical hydrogen generation H_(2))in H_(2)O and 1520.4 mL·g^(−1) H_(2)(about 95%)in 0.5 M MgCl2 in 60 min at 26℃ with hydrolysis rate of 736.9 mL·g^(−1)·min^(−1) and 960.9 mL·g^(−1)·min^(−1) H_(2) during the first minute of the hydrolysis,respectively.In addition,the MgCl2 solution allows repeated use by filtering and exhibits high cycle stability(20 cycles),therefore leading to much reduced capacity loss caused by the excess H_(2)O.We show that by introducing B2O_(3) and recycling the 0.5 M MgCl2 solution,the system hydrogen capacity can approach 5.9 wt%,providing a promising hydrogen generation scheme to supply hydrogen to the fuel cells. 展开更多
关键词 HYDROLYSIS MgH_(2) Mg(BH_(4))_(2) Hydrogen generation B2O_(3) MgCl2.
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Metallurgical properties of CaO–SiO_(2)–Al_(2)O_(3)–4.6wt%MgO–Fe_(2)O_(3)slag system pertaining to spent automotive catalyst smelting
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作者 Ruili Zheng Jianfang Lü +5 位作者 Weifeng Song Mudan Liu Huashan Li Yong Liu Xianjin Lü Zhiyuan Ma 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第5期886-896,共11页
The metallurgical properties of the CaO–SiO_(2)–Al_(2)O_(3)–4.6wt%Mg O–Fe_(2)O_(3)slag system,formed by the co-treatment process of spent automotive catalyst(SAC)and copper-bearing electroplating sludge(CBES),were... The metallurgical properties of the CaO–SiO_(2)–Al_(2)O_(3)–4.6wt%Mg O–Fe_(2)O_(3)slag system,formed by the co-treatment process of spent automotive catalyst(SAC)and copper-bearing electroplating sludge(CBES),were studied systematically in this paper.The slag structure,melting temperature,and viscous characteristics were investigated by Fourier transform infrared(FTIR)spectroscopy,Raman spectroscopy,Fact Sage calculation,and viscosity measurements.Experimental results show that the increase of Fe_(2)O_(3)content(3.8wt%–16.6wt%),the mass ratio of CaO/SiO_(2)(m(CaO)/m(SiO_(2)),0.5–1.3),and the mass ratio of SiO_(2)/Al_(2)O_(3)(m(SiO_(2))/m(Al_(2)O_(3)),1.0–5.0)can promote the depolymerization of silicate network,and the presence of a large amount of Fe_(2)O_(3)in form of tetrahedral and octahedral units ensures the charge compensation of Al^(3+)ions and makes Al_(2)O_(3)only behave as an acid oxide.Thermodynamic calculation and viscosity measurements show that with the increase of Fe_(2)O_(3)content,m(Ca O)/m(SiO_(2)),and m(SiO_(2))/m(Al_(2)O_(3)),the depolymerization of silicate network structure and low-melting-point phase transformation first occur within the slag,leading to the decrease in melting point and viscosity of the slag,while further increase causes the formation of high-melting-point phase and a resultant re-increase in viscosity and melting point.Based on experimental analysis,the preferred slag composition with low polymerization degree,viscosity,and melting point is as follows:Fe_(2)O_(3)content of 10.2wt%–13.4wt%,m(CaO)/m(SiO_(2))of 0.7–0.9 and m(SiO_(2))/m(Al_(2)O_(3))of 3.0–4.0.This work provides a theoretical support for slag design in co-smelting process of SAC and CBES. 展开更多
关键词 spent automotive catalyst co-treatment slag system slag structure melting temperature phase transformation VISCOSITY
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Mixing states and secondary formation processes of organic nitrogen-containing single particles in Guangzhou,China
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作者 Lijun Yun Chunlei Cheng +9 位作者 Suxia Yang Zaihua Wang Mei Li Qi En Zhong LiyuanMao Sulin Liu Xiaoya Cheng Duanying Chen Fan Yang Zhen Zhou 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2024年第4期62-73,共12页
Organic nitrogen(ON)compounds play a significant role in the light absorption of brown carbon and the formation of organic aerosols,however,the mixing state,secondary formation processes,and influencing factors of ON ... Organic nitrogen(ON)compounds play a significant role in the light absorption of brown carbon and the formation of organic aerosols,however,the mixing state,secondary formation processes,and influencing factors of ON compounds are still unclear.This paper reports on the mixing state of ON-containing particles based on measurements obtained using a highperformance single particle aerosol mass spectrometer in January 2020 in Guangzhou.The ON-containing particles accounted for 21% of the total detected single particles,and the particle count and number fraction of the ON-containing particles were two times higher at night than during the day.The prominent increase in the content of ON-containing particles with the enhancement of NO_xmainly occurred at night,and accompanied by high relative humidity and nitrate,which were associated with heterogeneous reactions between organics and gaseous NO_(x)and/or NO_(3)radical.The synchronous decreases in ON-containing particles and the mass absorption coefficient of water-soluble extracts at 365 nm in the afternoon may be associated with photo-bleaching of the ON species in the particles.In addition,the positive matrix factorization analysis found five factors dominated the formation processes of ON particles,and the nitrate factor(33%)mainly contributed to the production of ON particles at night.The results of this study provide unique insights into the mixing states and secondary formation processes of the ON-containing particles. 展开更多
关键词 Organic nitrogen compounds Single particles Mixing state Secondary formation Nighttime chemistry
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Selective leaching of lithium from spent lithium-ion batteries using sulfuric acid and oxalic acid
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作者 Haijun Yu Dongxing Wang +6 位作者 Shuai Rao Lijuan Duan Cairu Shao Xiaohui Tu Zhiyuan Ma Hongyang Cao Zhiqiang Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2024年第4期688-696,共9页
Traditional hydrometallurgical methods for recovering spent lithium-ion batteries(LIBs)involve acid leaching to simultaneously extract all valuable metals into the leachate.These methods usually are followed by a seri... Traditional hydrometallurgical methods for recovering spent lithium-ion batteries(LIBs)involve acid leaching to simultaneously extract all valuable metals into the leachate.These methods usually are followed by a series of separation steps such as precipitation,extraction,and stripping to separate the individual valuable metals.In this study,we present a process for selectively leaching lithium through the synergistic effect of sulfuric and oxalic acids.Under optimal leaching conditions(leaching time of 1.5 h,leaching temperature of 70°C,liquid-solid ratio of 4 mL/g,oxalic acid ratio of 1.3,and sulfuric acid ratio of 1.3),the lithium leaching efficiency reached89.6%,and the leaching efficiencies of Ni,Co,and Mn were 12.8%,6.5%,and 21.7%.X-ray diffraction(XRD)and inductively coupled plasma optical emission spectrometer(ICP-OES)analyses showed that most of the Ni,Co,and Mn in the raw material remained as solid residue oxides and oxalates.This study offers a new approach to enriching the relevant theory for selectively recovering lithium from spent LIBs. 展开更多
关键词 selective leaching oxalic acid sulfuric acid spent lithium-ion batteries
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钨渣吸附剂的制备及其对含铅废水的吸附 被引量:1
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作者 魏渤函 薛志远 +4 位作者 杨裕东 钟晓聪 任如山 王瑞祥 张魁芳 《Journal of Central South University》 SCIE EI CAS CSCD 2023年第6期1841-1855,共15页
为实现钨冶炼渣的资源化利用,通过正交试验和静态吸附试验,研究了钨渣-膨润土颗粒吸附剂制备的最佳成分比例和工艺条件。结果表明,颗粒吸附剂制备的最佳条件为:钨渣与膨润土的质量比为5:1,颗粒粒径为2 mm,烧结工艺为800℃,2 h。使用X射... 为实现钨冶炼渣的资源化利用,通过正交试验和静态吸附试验,研究了钨渣-膨润土颗粒吸附剂制备的最佳成分比例和工艺条件。结果表明,颗粒吸附剂制备的最佳条件为:钨渣与膨润土的质量比为5:1,颗粒粒径为2 mm,烧结工艺为800℃,2 h。使用X射线衍射仪和扫描电镜验证吸附剂主要形态为颗粒状的铁锰氧化物,其表面有大量的孔洞。在溶液pH为6,吸附剂用量为15 g/L,铅初始浓度为300 mg/L,吸附时间为200 min的条件下,吸附剂对废水中Pb2+的去除率达99.95%。该吸附剂对Pb2+的吸附过程符合准二级动力学方程,吸附等温线符合Langmuir方程,对Pb2+的吸附属于单分子层的特异性化学吸附。 展开更多
关键词 钨冶炼渣 资源化利用 吸附 含铅废水
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New insights into the formation of ammonium nitrate from a physical and chemical level perspective
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作者 Yuting Wei Xiao Tian +8 位作者 Junbo Huang Zaihua Wang Bo Huang Jinxing Liu Jie Gao Danni Liang Haofei Yu Yinchang Feng Guoliang Shi 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2023年第11期209-221,共13页
High levels of fine particulate matter(PM_(2.5))is linked to poor air quality and premature deaths,so haze pollution deserves the attention of the world.As abundant inorganic components in PM_(2.5),ammonium nitrate(NH... High levels of fine particulate matter(PM_(2.5))is linked to poor air quality and premature deaths,so haze pollution deserves the attention of the world.As abundant inorganic components in PM_(2.5),ammonium nitrate(NH_(4)NO_(3))formation includes two processes,the diffusion process(molecule of ammonia and nitric acid move from gas phase to liquid phase)and the ionization process(subsequent dissociation to form ions).In this study,we discuss the impact of meteorological factors,emission sources,and gaseous precursors on NH4NO3 formation based on thermodynamic theory,and identify the dominant factors during clean periods and haze periods.Results show that aerosol liquid water content has a more significant effect on ammonium nitrate formation regardless of the severity of pollution.The dust source is dominant emission source in clean periods;while a combination of coal combustion and vehicle exhaust sources is more important in haze periods.And the control of ammonia emission is more effective in reducing the formation of ammonium nitrate.The findings of this work inform the design of effective strategies to control particulate matter pollution. 展开更多
关键词 Ammonium nitrate formation Thermodynamic theory Aerosol liquid water content Source apportionment
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一种新型茴香羟肟酸捕收剂对钨、锡矿物的浮选性能研究 被引量:2
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作者 赵刚 周晓彤 +2 位作者 李方旭 付广钦 尚兴科 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第11期3645-3655,共11页
为了提升钨锡矿物的浮选回收,本文研究了一种新型羟肟酸捕收剂——对甲氧基苯甲羟肟酸(茴香羟肟酸,PMOB)对白钨矿、黑钨矿和锡石的浮选性能。以茴香酸乙酯为原料与盐酸羟胺通过肟化反应制备PMOB,采用质谱与核磁共振光谱对产物结构进行... 为了提升钨锡矿物的浮选回收,本文研究了一种新型羟肟酸捕收剂——对甲氧基苯甲羟肟酸(茴香羟肟酸,PMOB)对白钨矿、黑钨矿和锡石的浮选性能。以茴香酸乙酯为原料与盐酸羟胺通过肟化反应制备PMOB,采用质谱与核磁共振光谱对产物结构进行表征。单矿物浮选试验结果表明,在适宜的浮选pH条件下,PMOB对白钨矿、黑钨矿和锡石的回收率分别为97.45%、95.77%和90.08%,而苯甲羟肟酸(BHA)对三者的回收率分别为91.00%、84.30%和84.67%;根据黑白钨混合矿实际矿石浮选结果,获得相近的浮选指标时PMOB的用量比BHA降低约45%,浮选研究表明PMOB的捕收能力强于BHA。Zeta电位测试研究证实,在浮选pH区间,PMOB的吸附导致三种矿物的表面电性发生不同程度的负移,PMOB在矿物表面发生了化学吸附。此外,采用密度泛函理论(DFT)方法研究了取代基—OCH_(3)的电子效应,DFT计算结果表明,与苯甲羟肟酸、对甲基苯甲羟肟酸和对羟基苯甲羟肟酸相比,取代基团的引入提高了PMOB的给电子能力,增强了PMOB与矿物表面的结合能力,另一方面,甲氧基同时也提高了PMOB的疏水性能,对其捕收性能的提升起到促进作用。 展开更多
关键词 浮选 羟肟酸 白钨矿 黑钨矿 锡石
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Grain boundary construction and properties enhancement for hot deformed(Ce,La,Y)-Fe-B magnet by a two-step diffusion process
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作者 Xuefeng Liao Weiwei Zeng +10 位作者 Lizhong Zhao Qing Zhou Jiayi He Wei Li Xiangyi Liu Hongya Yu Xiaolian Liu Haoyang Jia Jean-Marc Greneche Xuefeng Zhang Zhongwu Liu 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2023年第34期253-261,共9页
The rare earth-iron-boron magnets based on high abundance rare earths(REs)show potential for costeffective permanent magnets but their hard magnetic properties have to be greatly improved.The grain boundary diffusion ... The rare earth-iron-boron magnets based on high abundance rare earths(REs)show potential for costeffective permanent magnets but their hard magnetic properties have to be greatly improved.The grain boundary diffusion process(GBDP)is known as an effective way to improve the coercivity of Nd-Fe-B magnets,however,the conventional diffusion method faces a challenge for Ce-based magnets since there is no enough continuous GB layer as the diffusion channel.Here,a two-step(Nd-Cu doping followed by Nd-Cu diffusion)GBDP was introduced for hot deformed(Ce,La,Y)-Fe-B magnet,and the excellent magnetic properties ofμ0Hc=0.63 T,μ0Mr=0.68 T,and(BH)max=72.4 kJ/m^(3)were achieved.The Nd-Cu doping helps the formation of RE-rich GB layer,and then it acts as the diffusion channel for increasing the ef-ficiency of the subsequent Nd-Cu diffusion and results in the increased volume fraction of continuously distributed GB phase,whose paramagnetism was verified by 57Fe Mössbauer spectrometry.Those paramagnetic GB phases help to form the discontinuous domain walls,as observed by Lorentz transmission electron microscopy,and break the magnetic exchange coupling of RE2Fe14B grains.It thus contributes to the coercivity enhancement of the hot deformed magnet with two-step diffusion,which is further proved by micromagnetic simulation.This study proposes a potential technique to prepare anisotropic hot deformed(Ce,La,Y)-Fe-B magnet with high cost-performance. 展开更多
关键词 High abundance rare earth Hot deformed RE-Fe-B magnets Grain boundary diffusion process Magnetic properties Grain boundary phase
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Holocene millennial-scale megaflood events point to ENSO-driven extreme climate changes
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作者 Cong CHEN Yanwei ZHENG +9 位作者 Zhuo ZHENG Yongqiang ZONG Kangyou HUANG Barry VROLETT Huanhuan PENG Xiao ZHANG Yongjie TANG Qiuchi WAN Guifang ZHANG Rachid CHEDADDI 《Science China Earth Sciences》 SCIE EI CAS CSCD 2023年第11期2530-2545,共16页
Reconstructing the Holocene megaflood history is a key component of understanding the mechanism of past climate change and assessing the potential impact of future catastrophic events.The Pearl River is the longest wa... Reconstructing the Holocene megaflood history is a key component of understanding the mechanism of past climate change and assessing the potential impact of future catastrophic events.The Pearl River is the longest watercourse in southern China,and its lower reach has been identified as one of the world's most vulnerable regions for flood exposure.However,there is a complete lack of millennial-scale geological records of paleomegafloods for the future prediction of once-in-a-hundred(even once-in-a-thousand)year floods in southern China.Here,we identified a series of paleomegaflood deposits interbedded with wood-rich peat layers in the lower West Pearl River area.All paleoflood layers have been well dated using AMS~(14)C dating method.According to the regional correlation of the flood sequence,sediment characteristics and provenance analysis,there have been at least 7 megafloods corresponding to once-in-a-thousand-year events in the lower reaches of the West Pearl River during the past 6000 years,with an average return period of approximately 855 years.The identified paleomegafloods were coeval with periods of strong El Ni?o-Southern Oscillation(ENSO),indicating that weakening of the Asian summer monsoon,associated with enhanced ENSO variability,may have triggered abnormally high precipitation leading to flooding of exceptional magnitude in southern China.In addition,the most prominent paleomegafloods identified in the lower Pearl River coincided with intervals of lower precipitation and fewer storms in central-eastern China,indicating the intensification of the meridional“tripole”pattern of precipitation across eastern China during the latter half of the Holocene.Increased land use and deforestation over the last 2000 years have resulted in soil loss and rapid degradation of local primeval forest ecosystems,leading to more catastrophic flooding.Large amounts of rice pollen in the uppermost flood layer during the Song Dynasty indicate that this megaflood may have inundated a large area of cultivated land.The periodic occurrence of Holocene megafloods not only caused damage to human existence,but also affected the evolution of local civilization.This study reveals for the first time a series of Holocene millennial-scale megafloods and sheds new light on the importance of atmosphere-ocean interactions in the tropical Pacific and monsoon subtropical climate dynamics for precipitation anomalies in East Asia.Our data yield valuable information for future research into climate extremes and hazard prevention. 展开更多
关键词 Holocene megaflood Asian monsoon ENSO Vegetation change Early farming West Pearl River
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