熔盐电解法制备镨钕钆合金的研究

本工艺采用熔融氟化锂-氟化镨钕-氟化钆熔盐三元体系为电解质,通过电解氧化钆与氧化镨钕混合物的方法,制备了成分稳定的镨钕钆合金,同时就电解质组元、温度、阴极电流密度、加料速度对电解过程的影响进行了试验研究。结果表明:在试验条件下可以生产钆含量(10~15)%±0.5%(质量分数)的镨钕钆合金,金属直收率大于98%,电流效率大于78%;产品含碳小于0.05%,含铁小于0.3%,含Ca,W均小于0.01%,同时具有成本低、工艺稳定、产品质量好等优点。     

钙熔盐电解石墨阳极破损机理及防护研究

通过扫描电镜和电子探针分析钙熔盐电解中破损石墨阳极的结构和杂质,探索了其破损机理,认为主要是由于孔隙存在导致氧化和孔隙吸附电解质,电解质因水解、脱水等过程使其周围的石墨阳极颗粒受应力不平衡而发生破损.通过实验研制出适合于钙熔盐电解过程用的石墨阳极具有抗氧化性能的涂层,并对涂层进行了XRD,SEM分析和氧化失重实验.实验表明该涂层在680～750℃下成硼玻璃态,能渗透到石墨阳极孔隙中,涂层表面致密无裂纹且附着力强,因而具有较好的抗氧化能力.该涂层是一种适合钙熔盐电解的、性能优良的石墨阳极涂层.     

Preparation of High-Purity Lithium Hydroxide Monohydrate from Technical-Grade Lithium Carbonate by Membrane Electrolysis

A scheme for preparing high-purity lithium hydroxide monohydrate from technical-grade lithium carbonate is suggested.     

Preparation,Structure and Magnetic Properties of Lithium Substituted NiO by Molten Salt Method

A typical Li⁺ substituted NiO compound, Li_0.29Ni_0.71O, was synthesized by molten nitrate method. The effects of Li⁺ substitution on the structure and magnetic properties of NiO were investigated. X-Ray diffraction(XRD), scanning electron microscope(SEM) and high-resolution transmission electron microscope(HRTEM) analyses confirm the cubic structure of Li_0.29Ni_0.71O, with a primary particle size of 150 nm. Analysis of the Ni X-ray photoelectron spectroscopy(XPS) shows the transformation from Ni²⁺ to Ni³⁺ induced by Li⁺ substitution. Two magnetic transitions were observed at 225 and 55 K which were assigned to the ferrimagnetic ordering and spin glass transition, respectively. The different magnetic behavior with respect to that of NiO was attributed to the break of superexchange interaction Ni²⁺-O-Ni²⁺ and the formation of different spin clusters after non-magnetic Li⁺ doping.     

MgCl2-KCl-NaCl-CaCl2熔盐电解镁机理

在725℃温度下,对MgCl2-KCl-NaCl-CaCl2熔盐体系进行电解.研究结果表明,镁电解过程中阴极过电压ηc只有12～51 mV,电解过程的过电压主要是由阳极引起的;阴极还原过程的极限扩散电流密度id为1.56 A/cm2;镁离子阴极放电反应的电子转移数为1.98;2个电子转移步骤之前存在着前置转化步骤MgCl+ Mg2++C1-.应用循环伏安法对4种不同配比下的镁离子行为进行的研究结果表明,CaCl2质量分数从10%增加到40%,维持MgCl2质量分数为10%以及NaCl与KCl的质量比为6: 1不变,随着CaCl2质量分数的增加,镁离子结合成不易移动的络合阴离子,镁离子迁移的电流分数减小,镁离子的析出电位从-1.595 V逐渐负移至与钙、钠共同沉积,阴极峰值电流Ipc值逐渐增大,阳极峰值电位与阴极峰值电位之差的绝对值|φpa-φpc|逐渐增大,阴极放电反应的可逆性逐渐降低.     

无机离子交换法从卤水中提锂的研究进展

无机离子交换法主要适合于从含锂较低的卤水中提取锂,是开发我国盐湖锂资源的重要研究方向之一。重点介绍了国内外无机离子交换法从卤水中提锂的研究进展,并指出了提锂的技术关键和发展方向。     

Molten Salt Derived Graphene-Like Carbon Nanosheets Wrapped SiOx/Carbon Submicrospheres with Enhanced Lithium Storage

Main observation and conclusion There is no doubt that SiOx and carbon composite is one of the promising anode materials for lithium-ion batteries owing to its ...     

熔盐法制备氧化锆纳米棒

采用非水解溶胶-凝胶工艺合成氧化锆干凝胶粉,然后将干凝胶粉与熔盐混合制备氧化锆纳米棒。借助DTA-TG、XRD、FE-SEM、TEM等测试手段研究了氧化锆的物相转变过程,探讨了熔盐种类与用量、氟化物的添加等工艺参数对制备氧化锆纳米棒的影响。结果表明：以NaVO₃为熔盐,用量为1：1（熔盐与干凝胶的质量比）,并且在添加氟化钠的条件下能够制备产率高,且沿[010] 方向择优生长的单斜氧化锆纳米棒;氟离子一方面加速了熔盐中Zr⁴⁺离子的传质,促使氧化锆干凝胶粉的溶解,另一方面吸附在氧化锆的高能晶面上抑制该晶面的生长,两者的共同作用促进了大量氧化锆纳米棒的形成。     

熔盐法制备氧化锆纳米棒

采用非水解溶胶-凝胶工艺合成氧化锆干凝胶粉,然后将干凝胶粉与熔盐混合制备氧化锆纳米棒。借助DTA-TG、XRD、FE-SEM、TEM等测试手段研究了氧化锆的物相转变过程,探讨了熔盐种类与用量、氟化物的添加等工艺参数对制备氧化锆纳米棒的影响。结果表明:以Na VO3为熔盐,用量为1∶1(熔盐与干凝胶的质量比),并且在添加氟化钠的条件下能够制备产率高,且沿[010]方向择优生长的单斜氧化锆纳米棒;氟离子一方面加速了熔盐中Zr4+离子的传质,促使氧化锆干凝胶粉的溶解,另一方面吸附在氧化锆的高能晶面上抑制该晶面的生长,两者的共同作用促进了大量氧化锆纳米棒的形成。     

熔盐电解法制备纳米碳管及纳米线

以LiCl、LiCl+SnCl2等为熔盐电解质,采用电解石墨的方法制备了纳米碳管和纳米线,并运用TEM、XRD、EDS等分析手段对产物的形貌和结构进行了表征.结果表明,熔盐成分对电解产物的形态和性质有显著影响.在LiCl熔盐中可得到直径为75～100nm的纳米碳管;在LiCl+1.0%SnCl2熔盐中可生成β-Sn填充的纳米碳管.XRD测试表明,电解制备的β-Sn纳米线经氧化处理后在碳管内可转变为SnO2,其晶体结构为四方晶系,直径为20～50 nm.电解过程中Li+在石墨阴极上反应生成的LiC6化合物对纳米碳结构的形成具有重要作用.     

BaKPbO和BaKPbBiO的熔盐阳极电结晶

钙钛石（ＡＢＯ３）型复杂氧化物由于Ａ位、Ｂ位在适当范围内掺杂其他离子而成为性能宽广的功能材料．例如ＢａＰｂＯ３及其取代物ＢａＰｂＢｉＯ是甲烷偶联反应的催化剂［１］,ＢａＰｂＢｉＯ［２］和ＢａＫＢｉＯ［３］还具有超导性．另一方面,这些复杂氧化物的功能又?..     

Biohydrometallurgy for Rare Earth Elements Recovery from Industrial Wastes

Biohydrometallurgy recovers metals through microbially mediated processes and has been traditionally applied for the extraction of base metals from low-grade sulfidic ores. New investigations explore its potential for other types of critical resources, such as rare earth elements. In recent times, the interest in rare earth elements (REEs) is growing due to of their applications in novel technologies and green economy. The use of biohydrometallurgy for extracting resources from waste streams is also gaining attention to support innovative mining and promote a circular economy. The increase in wastes containing REEs turns them into a valuable alternative source. Most REE ores and industrial residues do not contain sulfides, and bioleaching processes use autotrophic or heterotrophic microorganisms to generate acids that dissolve the metals. This review gathers information towards the recycling of REE-bearing wastes (fluorescent lamp powder, spent cracking catalysts, e-wastes, etc.) using a more sustainable and environmentally friendly technology that reduces the impact on the environment.     

Mo,W电极在MgCl2-KCl-NaCl-CaCl2熔盐中电解镁的钝化行为

应用循环伏安法和计时电流法研究了Mg(Ⅱ)在MgCl2-KCl-NaCl-CaCl2四元熔盐体系中于(Mo、W)阴极上的放电过程及其钝化行为.结果表明,W电极放电反应的可逆性比Mo电极的好.后者的计时电流曲线偏离线性特征,且其阴极钝化比W严重.     

熔盐电化学创新研究——武汉大学电化学研究中心熔盐电化学研究工作简介

简要介绍近3年武汉大学电化学研究中心在熔盐电化学方面的若干研究进展:1)熔盐电解固态化合物制备单质硅及其合金以及无机功能材料;2)适于高温熔盐的全密封长寿命Ag/AgCl参比电极和可负载微量粉末的金属腔(坑)工作电极新技术;3)“三相界线电化学”新概念以及描述三相界线在薄层固态化合物电解还原过程中扩展变化的薄层模型.     

Effective Removal of Cesium and Strontium from Radioactive Wastes Using Chemical Treatment Followed by Ultra Filtration

Chemical treatment assumes an important role in the management of radioactive wastes as it is a simple technique and offers advantage in terms of handling of wastes thereby reducing the risk of mansievert exposure. Low level wastes (LLW) and intermediate level wastes (ILW) are generated in various facets of nuclear fuel cycle and have various chemical composition. A systematic study was carried out by using copper ferrocyanide and calcium phosphate precipitation methods for the removal of cesium and strontium, respectively. The supernatants were subjected to ultra filtration (UF) using a membrane having a pore size of 0.2 m. The decontamination factors (DF) at 2 and 24-hour intervals with and without UF were estimated. The DF obtained was in the range of 200–300 for cesium and 200 for strontium with LLW solution which has chemical characteristics similar to ground water. Two hours of settling is adequate for strontium before UF. In case of cesium there is no much change in the DF values by UF. However, the UF has helped in the solid — liquid separation as the flocks of copper ferrocyanide precipitate are feathery in nature. The effect of ionic strength and the presence of TBP on the removal efficiency of cesium and strontium have also been studied. DF are observed to be a function of ionic strength and are low in deionized water, in salt solutions containing 1 to 4M sodium nitrate and also in solutions of ILW. However, increasing the chemical dosing to two times of normal plant dosing has yielded a DF of about 200 for sodium nitrate solutions with respect to cesium removal. When the concentration of ammonium nitrate in the waste exceeds 0.1M, the DF reduces. Entrained TBP as well as soluble TBP reduces the removal efficiency of cesium. This paper deals with the experimental data and mechanism of the processes involved in the removal of cesium and strontium.     

熔盐法合成NiO纳米微晶

纳米科技的基础是纳米结构材料的合成．它是纳米科技在分散与包覆、高比表面材料、功能纳米器件、强化材料等方面实现突破的起点。纳米颗粒（1-100nm）本身具有宏观量子隧道效应、量子尺寸效应、表面效应许多独特的性能．其制备研究日益得到广泛关注和重视．     

Low-Temperature Synthesis of Honeycomb CuP2@C in Molten ZnCl2 Salt for High-Performance Lithium Ion Batteries

Phosphorus-rich metal phosphides have very high lithium storage capacities, but they are difficult to prepare. A low-temperature phosphorization method based on Mg reducing PCl₃ in ZnCl₂ molten salt at 300 °C is developed to synthesize phosphorus-rich CuP₂@C from a Cu-MOF derived Cu@C composite. Abnormal oxidation of Cu by Zn²⁺ in the molten salt is observed, which leads to the porous honeycomb nanostructure and homogeneously distributed ultrafine CuP₂ nanocrystals. The honeycomb CuP₂@C exhibits excellent lithium storage performance with high reversible capacity (1146 mAh g⁻¹ at 0.2 A g⁻¹) and superior cycling stability (720 mAh g⁻¹ after 600 cycles at 1.0 A g⁻¹), showing the promising application of P-rich metal phosphides in lithium ion batteries.     

低温熔融盐合成富磷相CuP_2纳米材料及其储锂应用

正纳米过渡金属磷化物(MP_x,M=Cu,Ni,Fe,等)在电催化,光催化,超级电容器以及锂离子电池等领域具有很大的应用前景~(1–3)。在储锂应用中,过渡金属磷化物的理论容量与磷的含量成正比,因此富磷的过渡金属磷化物最具吸引力。但目前富磷MP_x的合成比较困难,往往需要特殊的合成条     

熔盐法制备结晶二氧化硅粉体

以硅酸四乙酯为原料,氯化钠和氯化钾为助熔剂和催化剂,采用熔盐辅助法制备了系列结晶二氧化硅粉体,其结构经XRD和SEM表征。研究了工艺参数对其性能的影响。结果表明:反应温度和熔盐组成对其结晶性和微观形貌具有显著影响。     

熔融法制备纳米管Li-Ti-O化合物及其表征

在熔融的LiNO₃中，以纳米管钛酸钠为母体进行锂-钠离子交换，制得了具有高表面积的纳米管Li-Ti-O化合物(198.6 m²·g^-1)。XRD、XPS、TG表征结果表明: 此纳米管Li-Ti-O化合物包含两种晶型物质, 即立方尖晶石结构的Li₂Ti₂O₄和锐钛矿结构的Li_xTiO₂(x＜0.1)]，Li⁺在这两种晶型物质中的结合能不同；在空气中此纳米管Li-Ti-O化合物具有较强的吸水性，化学吸附水在高于400 ℃时才开始脱附。