A Novel Ion-exchange Method for the Synthesis of Nano-SnO/micro-C Hybrid Structure as High Capacity Anode Material in Lithium Ion Batteries

A novel and simple ion-exchange method was developed for the synthesis of nano-SnO/micro-C hybrid structure. The structure of the as prepared nano-SnO/micro-C was directly revealed by scanning electron microscopy（SEM） and transmission electron microscopy（TEM）.SnO particles with the size about 25 nm were well confined in amorphous carbon microparticles.Carbon matrix in micrometer scale not only acts as a protective buffer for the SnO nanoparticles during the battery cycling processes,but also avoids the shortcomings of nanostructures, such as low tap density and potential safety threats.Electrochemical behaviors of the nano-SnO/micro-C were tested as anode material in lithium ion batteries.The initial reversible capacity is 508 mA h g^-1,and the reversible capacity after 60 cycles is 511 mA h g^-1,indicating good capacity retention ability.     

First-principle investigation on mechanism of Ca ion activating flotation of spodumene

Different hypotheses of the activation mechanisms of metallic ions for silicate minerals flotation were stated in this work. Spodumene and Ca ion were taken to illustrate this issue. Flotation test results and diagram of Ca ion species distribution vs pH show that the dominant hydrolyzed species are Ca（OH）？and Ca（OH）2, which is in correspondence with the maximum flotation recovery of spodumene. Density functional theory（DFT） calculation results reveal further that the precipitation of calcium hydroxide on spodumene surface is the effective process to activate the flotation of spodumene.     

矿物原料制备聚合氯化铝的研究进展

综述了利用高岭土、铝矾土、煤矸石等矿物原料制备聚合氯化铝的研究进展,简要分析了利用矿物原料制备聚合氯化铝普遍存在的问题,并对新的研究方向做了展望。     

Migration and distribution of saline ions in bauxite residue during water leaching

Bauxite residue, a highly saline solid waste produced from digestion of bauxite for alumina production, is hazardous to the environment and restricts vegetation establishment in bauxite residue disposal areas. A novel water leaching process proposed here was used to investigate the dynamic migration and vertical distribution of saline ions in bauxite residue. The results show that water leaching significantly reduced the salinity of bauxite residue, leaching both saline cations Na⁺, K⁺, Ca²⁺ and anions CO^2?₃, SO^2?₄, HCO^?₃. Na⁺ and K⁺ migrated from 40–50 to 20–30 cm of the column, presenting a high migration capacity. The migration capacity of Ca²⁺ was lower and accumulated at 30–40 cm of the column. CO^2?₃ initially distributed at 20–30 cm of the column, subsequently transported to 30–40 cm of the column, and finally returned to 20–30 cm of the column along with evaporation. SO^2?₄ was originally distributed at 40–50 cm, but finally migrated to 20–30 cm of the column. Nevertheless, HCO^?₃ remained at the bottom of the column, and its migratory was less affected by evaporation.     

A new kinetic model for Ni(II) ion flotation based on gene expression programming

ABSTRACT

The Ni(II) ion flotation kinetics with sodium dodecylsulfate as collector was studied with the aim of developing new models to predict the flotation rate constant (k) of Ni(II) ions and water removal during the process of Ni(II) ion flotation. In this regard, the most influential parameters on Ni(II) ion flotation efficiency including the ratio of collector concentration on the Ni(II) ion concentration, impeller speed, activity coefficient, and pH were used to develop predictive models. The results show that the proposed gene expression programming models can be used to predict the flotation rate constant of Ni(II) ions and water removal.     

氯化亚铁在氯化尾气淋洗中的应用研究

氯化亚铁溶液因其制备工艺简单，原料价格低廉等，被作为还原剂广泛应用于化工领域和冶金领域。试验主要应用其易与氯气发生化学反应的特点，创新地应用到氯化生产中的尾气治理方面，有效解决因长期依赖碱液淋洗尾气带来的管道堵塞现象及二次污染等问题。     

Reversible Flat to Rippling Phase Transition in Fe Containing Layered Battery Electrode Materials

Layered sodium transition metal oxides of NaTMO₂ (TM = 3d transition metal) show unique capability to mix different compositions of Fe to the TM layer, a phenomenon that does not exist in LiTMO₂. Here, a novel spontaneous TM layer rippling in the sodium ion battery cathode materials is reported, revealed by in situ X‐ray diffraction, Cs‐corrected scanning transmission electron microscopy, and density functional theory simulation, where the softening and distortion of FeO₆ octahedra collectively drives the flat TM planes into rippled ones with inhomogeneous interlayer distance at high voltage. In such a rippling phase, charge and discharge of Na ions take different evolution pathways, resulting in an unusual hysteresis voltage loop. Importantly, upon discharge beyond a certain Na composition, the rippling TM layer will go back to flat, giving the reversibility of such structural evolution in the following cycles.     

Polybutadiene/polyhedral oligomeric silsesquioxane nanohybrid: investigation of various reactants in polyesterification reaction

Nano‐sized polyhedral oligomeric silsesquioxane (POSS) diol or ethylene glycol (EG) as diol monomer was incorporated into hydroxyl‐terminated polybutadiene (HTPBD) chain in the presence of fumaryl or thionyl chloride as extenders. Using these polyesterification reactions, two fumarate‐based polyesters and two polyester sulfites were synthesized. Each couple of polyesters and polyester sulfites includes a linear (diol:EG) and a nanohybrid macromer (diol:POSS). Full structural characterization was performed using Fourier transform infrared, ¹H NMR and ¹³C NMR spectroscopies. Gel permeation chromatography was undertaken to study polyesterification mechanisms by deconvolution of the obtained traces. Finally, differential scanning calorimetry, thermogravimetric analysis and cell culture were performed to evaluate the structure–property relationship for the synthesized macromers in comparison with unreacted HTPBD. © 2016 Society of Chemical Industry     

锂离子电池的可逆及不可逆产热测试

针对商业化的圆柱型18650锂离子电池,对其在充放电过程中的可逆及不可逆产热参数分别进行测试和计算,结合绝热加速量热仪(ARC)对电池放热的实测数据进行拟合分析,结果表明:根据该测试方法计算的可逆及不可逆产热数值与实测值具有很好的吻合性;该电池在0.3 C充放电过程中的总产热功率变化情况由可逆产热功率决定;可逆产热功率在电池荷电态为20%~60%区间内呈现出一个最高峰,对应电池发生熵变的脱嵌锂电化学主反应;不可逆产热功率在低荷电态下较高,而在其他荷电区间内变化幅度较小;电池在充放电过程中的总产热功率曲线是以不可逆产热功率曲线为对称轴,而在形状上基本呈现为上下对称。     

Flocculation and mechanism of self-flocculating lipid producer microalga Scenedesmus quadricauda for biomass harvesting

In this study, the extracellular polymeric substance of Scenedesmus quadricauda called EPS-S.q and its bioflocculatoin mechanism were investigated. Results showed EPS-S.q was successfully used as bioflocculating agent for S. quadricauda biomass harvesting and flocculation efficiency of up to 86.7% to S. quadricauda cells could be achieved in presence of Zn²⁺. EPS-S.q was the flocculating agent for self-flocculating microalga S. quadricauda and bioflocculation mechanism was polymer bridging. The sugar and protein mass fraction of dry EPS-S.q was sugar 56.7% and protein 41%. The infrared spectrum further indicated the presence of hydroxyl, carboxyl and amino groups. Moreover, pH decrease induced the flocculation of S. quadricauda and 78.4% of flocculation efficiency was the highest at pH 3. In addition, chemical flocculant FeCl₃ was efficiently used for S. quadricauda harvesting and up to 96.8% of flocculation efficiency could be achieved for S. quadricauda culture with biomass concentration 0.21–0.39 g L⁻¹ at pH 7.