锂离子筛前驱体LiMn2O4的制备及锂吸附性能研究

以氢氧化锂和乙酸锰为主要原料,采用溶胶-凝胶法合成了尖晶石型LiMn2O4前驱体,经酸浸脱锂后得到对Li+具有特殊选择性吸附的离子筛,采用XRD、SEM、吸附动力学等手段对前驱体及相应离子筛的晶相结构及吸附性能进行了研究。结果表明,由550℃煅烧10h制备出的前驱体LiMn2O4中表现出最好的结构稳定性,酸浸转型之后锂离子筛能够保持尖晶石锂锰氧化物的结构,离子筛的最大吸附容量达到32mg/g。     

锂锰氧化物离子筛的研究进展

尖晶石型锂锰氧化物是目前最具发展前景的锂吸附剂.介绍了锂锰氧化物的合成方法及结构、Li+的抽提/嵌入反应机理和锂离子筛吸附锂过程中的影响因素,讨论了对目前在锂吸附剂的制备及实际应用等方面存在的问题,并展望了锂锰氧化物离子筛未来的研究方向.     

TiO2离子筛的合成及锂吸附性能研究

以离子筛型氧化物为关键材料的锂离子选择性吸附技术是近年来盐湖卤水提锂的重要研究方向.采用商品TiO2经过研磨、焙烧浸锂、酸洗脱锂和干燥过程制备得到立方晶相尖晶石结构的TiO2离子筛,通过XRD和SEM对样品晶相结构和表面形貌进行了表征,探索了焙烧温度和Li/Ti比对离子筛前驱体结构的影响,进一步对Li+吸附性能进行了研究.结果表明,当Li/Ti摩尔比为0.9,TiO2和Li2CO3在1173K焙烧24h后得到了近乎为纯晶相的尖晶石结构Li4Ti5O12前驱体,经酸脱锂后得到对Li+具有记忆效应的TiO2离子筛,对Li+的平衡吸附量为2.530 mmol/g.     

低维纳米立方相Li_4Mn_5O_(12)的制备及锂吸附性能

以MnSO4·H2O和(NH4)2S2O8为原料通过控制水热反应条件合成了纯的四方相β-MnO2纳米氧化物,进一步通过低温固相法制备了立方相Li4Mn5O12,经酸浸脱锂后得到对Li+具有特殊选择性的MnO2离子筛.用XRD、HRTEM、SAED、吸附等温线、吸附动力学及共存金属离子的分配系数等手段对产物的晶相结构和Li+选择性吸附性能进行了研究.HRTEM和SAED图像表明氧化物MnO2、前驱体Li4Mn5O12和离子筛MnO2均为低维纳米棒.离子筛的最大吸附量达到6.6mmol/g,且当Li+初始浓度仅为5.0mmol/L时,离子筛的吸附量即可达到约5.0mmol/g,这对于在海水或锂离子浓度极低的盐湖卤水提锂具有重要的实用意义.     

PVDF为成膜材料制备锂离子筛膜的性能研究

将锂锰氧化物(Li1.6Mn1.6O4)添加到聚偏氟乙烯(PVDF)铸膜液中,通过相转化法制备了掺杂Li1.6Mn1.6O4的锂离子筛前驱体膜,经过盐酸处理洗脱锂离子后制得锂离子筛膜。采用X射线衍射、扫描电镜、吸附实验等手段对膜的结构和吸附性能进行表征。吸附实验表明,随着Li1.6Mn1.6O4含量的增加,锂离子筛膜的吸附量先增加后减小。当添加Li1.6Mn1.6O4的质量分数为15%时,锂离子筛膜的吸附量最高为6.98×102 mg/cm2。     

锂离子筛前驱体Li4Mn5O12的制备及性能研究

吸附法是目前从低锂浓度的盐湖卤水中提取锂的最有前途的方法。采用EDTA-柠檬酸络合法制备了Li₄Mn₅O₁₂前驱体, 经酸浸脱锂后得到对Li⁺具有特殊选择性的锰氧化物锂离子筛。通过热重、XRD、SEM、FT-IR、化学组成、吸附动力学及共存金属离子的分配系数等手段对样品的晶相结构和Li⁺选择性吸附性能进行了研究。结果表明: 煅烧时间对Li₄Mn₅O₁₂前驱体生成有较大影响, 由400℃煅烧24 h所得的前驱体几乎为纯相的Li₄Mn₅O₁₂化合物, 经酸浸脱锂后的离子筛仍保持着与前驱体相同的尖晶石结构; 前驱体Li₄Mn₅O₁₂和离子筛MnO₂均为 200 nm左右的球状颗粒; 离子筛的最大吸附容量为43.1 mg/g, 并具有较好的Li⁺选择性。     

锂离子筛的制备及其吸附性能研究

采用水热法制备γ-MnOOH,结果表明在温度140℃,KMnO4的量为0.5g时制备的γ-MnOOH结晶效果良好;以自制的γ-MnOOH与Li OH反应制备出离子筛前驱体,对酸洗后所得的锂离子筛的吸附性能进行了系统研究。研究结果表明,pH值12时吸附量最高,不同初始锂溶液浓度条件下锂的吸附量相差较小,锂离子筛对锂的吸附过程可用Langmuir模型来描述。     

水热法合成铬掺杂尖晶石型锂离子筛及其锂吸附性能

以LiOH、H2O2、Mn(NO3)2和Cr(NO3)3·9H2O为原料,直接水热合成出具有尖晶石结构的铬元素掺杂锂离子筛前驱体,再经酸浸脱锂后得到对Li+具有选择吸附性能的掺杂型锂离子筛;采用XRD和1R研究了产物的性能,测定了离子筛在不同pH值的纯锂溶液中对锂的饱和交换容量.结果表明,在LiOH浓度为1.1mol/...     

富锂材料0.6Li[Li_(1/3)Mn_(2/3)]O_2-0.4LiMO_2的制备及其电化学性能

通过共沉淀法制备得到不同钴镍锰比例的M(OH)2(M=Ni,Mn,Co)前驱体,经配锂焙烧合成富锂锰基锂离子电池正极材料0.6Li[Li1/3Mn2/3]O2-0.4LiMO2。XRD测试结果表明材料具有α-NaFeO2层状晶体结构,SEM结果显示材料粒径在200~400nm。当Ni∶Mn∶Co=5∶2∶3,得到的富锂锰基氧化物0.6Li[Li1/3Mn2/3]O2-0.4Li(Ni0.5Mn0.2Co0.3)O2材料在2.0~4.6V范围内,表现出优良的循环性能,循环30次后,容量保持率为92.8%。     

基于不同洗脱剂的单斜晶系钛基锂离子筛的制备及其吸附性能

采用高温固相法,以碳酸锂和二氧化钛为原料合成了锂离子筛前驱体,并分别考察了0.5mol/L盐酸和0.8mol/L过硫酸钠溶液对前驱体的洗脱及产物锂离子筛的吸锂过程。结果表明,0.5mol/L的盐酸作洗脱剂,循环洗脱-吸附5次后离子筛在含锂溶液(等体积0.01mol/L LiCl和0.01mol/L LiOH混合液)中的吸锂量稳定在18mg/g左右;0.8mol/L的过硫酸钠作洗脱剂,5次循环洗脱-吸附后对锂的吸附量约为16mg/g;吸锂过程适宜用伪二级动力学模型描述,且过硫酸钠的洗脱及所得离子筛的吸附动力学性能均优于盐酸作为洗脱剂的情况;过硫酸钠作洗脱剂有助于改善单斜晶系钛基锂离子筛的动力学性能。研究结果有助于拓宽锂离子筛的制备及应用。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from