Lithium-ion batteries (LIBs) have become the primary energy storage solution for the new energy industry. Efficient and environmentally friendly recycling of valuable metals from spent LIBs is crucial for mitigating environmental pollution and ensuring resource sustainability. This study proposes a clean process combining in situ carbothermal reduction with wet magnetic separation to recover valuable metals from spent LIBs. Thermodynamic calculations and experimental results confirmed that cathode materials (LiNixCoyMn(1-x–y)O2) can be reduced and decomposed by anode graphite to form Fe–Ni–Co alloy, Li2CO3 or Li2O, and MnO. These products were effectively separated and enriched into magnetic concentrate, selective leaching solution, and non-magnetic slag, respectively. Under optimal conditions—carbothermal reduction at 1000 °C for 120 min, followed by wet magnetic separation at 70 °C with 18.3 wt

Objective At the microscale, the increased surface area-to-volume ratio greatly enhances the effect of surface forces, making them essential for fluid control. In mixed systems, the composition of the interfacial layer often differs substantially from that of the bulk phase. While this difference has minimal influence on surface tension measurement at the macroscopic scale, where the interfacial layer's thickness is comparable to the amplitude of surface waves, it becomes critical at the microscopic scale. Surface tension, a macroscopic thermophysical property, depends not only on the free energy at the interface but also on the adsorption of solute molecules in the adjacent interfacial layer. Thus, microscale variations play a crucial role in surface adsorption, necessitating the study of methods to measure liquid surface tension in microchannels under in situ conditions. Methods In this paper, we propose a novel experimental system designed for light scattering on reflective surfaces, with adjustable micrometer-scale channel widths. In addition, a microscale liquid level control platform is developed, incorporating three-dimensional motion and a rotary stage that rotates along the z-axis to control dimensions in the x, y, z, and phi directions. Precise movement in the x-direction is achieved using a one-dimensional digital displacement stage, which offers a stroke of 25.4 mm and a step accuracy of 1 mu m. This system enables the creation of microchannels ranging from 10 to 100 mu m in width, with the capability to continuously vary channel dimensions by several micrometers. The power spectrum equation for surface waves in microscale channels is derived based on strict boundary conditions. Surface tension is determined by applying this equation to the channel data, following time-domain data processing techniques such as zero-channel-point acquisition, data folding, and discrete fast Fourier transform. Results and Discussions The power spectra of surface waves confined within microchannels of different widths at 298.15 K and atmospheric pressure are obtained using isooctane. As the channel width increases, the power spectrum shifts to lower frequencies, while the peak value gradually rises. According to Eq. (6), as the channel width increases, the extracted wavelength also increases, leading to a decrease in scattering angle and intensity, thus raising the power spectrum's peak (Fig. 5). Minor deviations between measurements of the three standard substances and the reference data, as well as slight variations in repeated single-point measurements, demonstrate that the new system offers enhanced precision, consistency, and reliability across a wide range of channel widths or wave numbers. Furthermore, the first-order approximate solutions for iso-octane, n-decane, and hexadecane increasingly deviate due to the neglect of body-phase dissipation near the critical oscillatory region. The primary approximation applies only to extremely large Y values (e.g., Y>100), indicating extremely low viscosities (Fig. 6). In most practical cases, fluids do not meet this condition, resulting in significant systematic deviations when determining surface tension using this approach. Conclusions We propose an experimental system for measuring light scattering on microscale reflective surfaces and assess its accuracy and reliability using iso-octane, n-decane, and n-hexadecane under ambient temperature and pressure. The key findings are as follows. First, the surface wave power spectrum equation for microscale channels is derived by considering the surface wave dispersion equation and boundary conditions. Second, by integrating a precisely adjustable microchannel (30 to 90 mu m) with a reflective light scattering system, we successfully measure fluid surface tension with minimal sample volumes (about 2 mu L). Third, we validate the new system and measurement method using reference materials, and the discrepancies between the experimental and theoretical surface tension values for the three alkanes are within 3%, with single-point measurements taking only a few seconds. This meets the requirements for high-precision surface tension measurement and sensing. Lastly, a comparison of the surface wave power spectrum equation and the first- order approximation equation shows that the former accurately calculates surface tension in microscale channels, while the latter introduces significant systematic deviations.

This work investigates the phase diagram and thermophysical properties of the binary, ternary and quaternary nitrates containing NaNO3, KNO3, Ca(NO3)2 and LiNO3. We developed an equal-composition method to predict the eutectic point and the corresponding composition based on the CALPHAD method with the FactSage software. This approach enables the expansion of existing binary and ternary phase diagrams to a quaternary one while maintaining consistency with the ternary phase diagrams. The melting temperature at the eutectic point was predicted to be 382.19 K with the molar composition of 9.16 % NaNO3 / 49.91 % KNO3 / 13.93 % Ca(NO3)2 / 27 % LiNO3, respectively. The melting point, eutectic point, and specific heat capacity measured at the predicted eutectic point were 352.1 K, 383.9 K, and 1.30 kJ.kg-1.K-1, respectively. The decomposition temperature was determined to be 833.17 K with thermogravimetric analysis method. This work provided an efficient way of constructing quaternary phase diagram for molten salts and could facilitate the selection of low melting point molten salts that applicable to the thermal energy storage applications.

Generally, hydrometallurgy process is adopted in factory to recover valuable metal from anode materials in lithium ion battery. The mother liquor generated from the precipitation of lithium carbonate in this process is often managed by evaporative crystallization process which is high energy-consuming and expensive. The methodology employed in this research involves pretreatment and bipolar membrane electrodialysis to partition salts within the mother liquor into acids and bases, thereby achieving cost savings. The findings reveal that a significant 76.5% reduction in COD is achievable through the application of potassium permanganate and activated carbon in the treatment of the mother liquor. Subsequently, the treated mother liquor can be transfer to electrodialysis process for further treatment. During this process, desalination of the mother liquor occurs, leading to the decomposition of sodium sulfate into sulfuric acid and sodium hydroxide. Analysis of the experimental data reveals that optimizing the initial concentrations of sulfuric acid and sodium hydroxide within the acid and alkali collection chambers, along with the application of elevated electric current density and maintaining a high pH value of the mother liquor, yields improvements in current efficiency and concomitant reductions in energy consumption. Under optimal conditions, the current efficiency of acid and alkali preparation is 52.53% and 62.12% respectively, along with energy consumption of acid and alkali preparation is 8.68kWh/kg and 8.99kWh/kg respectively. The pretreatment and bipolar membrane electrodialysis process is low-energy consumption and inexpensive, facilitating a reduction in processing expenses to $6.659 per ton of mother liquor.

Fatty acid methyl/ethyl esters have a potential application as fuel or fuel additives in internal combustion diesel engine. The present work focused on the determination of the liquid thermal diffusivity of six fatty acid methyl esters (FAMEs) and four fatty acid ethyl esters (FAEEs) over a wide temperature range from (303.15 to 473.15) K by dynamic light scattering (DLS) method. Results demonstrated that the liquid thermal diffusivity of FAMEs and FAEEs decreased as the increasing temperature but increased as the increasing carbon chain. Furthermore, the polynomial correlation of the liquid thermal diffusivity against the temperature was proposed. The maximum relative deviation (MRD) and absolute average relative deviation (AARD) between experimental data and the corresponding calculated values from the correlation were 2.00% and 1.00%, respectively. The obtained experimental data and proposed correlation in this study provide necessary data support for future industry applications of FAMEs and FAEEs as fuels or fuel additives in internal combustion engines.

This work employs a theoretical power spectrum of the dynamics of surface fluctuations in the frequency domain to elucidate the dissipation of capillary waves of fluids in the near-critical oscillation or transition region, seeking to resolve the problem of large discrepancies in viscosity and surface tension measurements in the region. The frequency-domain analysis approach was suggested, involving the discrete Fourier transform to transform the time domain data to the frequency domain and the fitting algorithm for the power spectrum. A total of three refrigerants, four alkanes and six fatty esters were chosen to examine the approach, with a range of the dimensionless number Y between 1.3 and 101.9. The findings demonstrate that frequency-domain approach is an effective way of dealing with dissipation issues for surface light scattering method when approaching the critical oscillation region, and thus could extend the technique for determining the viscosity and surface tension of Newtonian fluids to a sufficient wide viscosity range.

Based on the principle of dynamic light scattering, this paper develops a set of dynamic light scattering apparatus which can measure the thermal diffusivity. The experimental system includes scattering light path, pressure vessel, temperature control system, and data acquisition system. The optical fiber is introduced into the dynamic light scattering system as a probe, which reduces the experimental system to 1/3 of the similar system. In this paper. the reference fluid n-hexane was used to test the accuracy of the experimental system. The thermal diffusivity obtained from the experiment was fitted into a polynomial equation with a maximum deviation of 0. 19%, an average absolute deviation of 0. 11%, and the maximum deviation between experimental and literature values was 3%. After uncertainty analysis. the uncertainty of liquid thermal diffusivity measured by the newly developed dynamic light scattering experimental system is 2% (k=2).

基于改进相变模型和工质饱和蒸汽压关系式对重力热管相变传热过程进行数值模拟,通过与文献结果和该文实验数据的对比,分析了冷凝过程质量转换时间松弛因子(冷凝系数)和相变判据对模拟结果的影响.结果表明:通过对冷凝系数的优化促进了热管启动过程的热质平衡,合理控制冷凝系数的变化速率可显著降低计算域质量偏差,并提高管壁温度模拟精度;饱和温度对热管蒸发段壁面温度影响最大,对冷凝段壁面温度影响最小,同等条件下低于合理取值的饱和温度将导致更大的管壁温度模拟偏差;采用工质饱和蒸汽压关系式作为相变判据能获得合理的饱和温度,模拟结果与实验值具有良好的一致性;基于改进模型的数值模拟结果直观再现了热管内部相变传热传质过程.结果可为热管相变传热数值模型的优化改进提供指导,有助于加深对热管内部传热机理的认识.

赤泥是氧化铝生产过程中产生的强碱性固体残渣,强碱性限制了其在水泥等领域的大宗应用,亟待开发赤泥高效脱碱技术和配套的钠含量分析检测技术.本文采用火焰原子吸收分光光度法测量拜耳法赤泥中钠,对现有方法进行了改进,选用盐酸(1+1)消解赤泥样品,无需使用贵金属坩埚,优化了样品消解时间,并采用KCl有效消除了钠元素的电离干扰,纠正了文献中KCl的有效浓度范围.在优化测量条件下,加标回收率在99.17%～105.00%,赤泥标准样品测量相对误差在-0.22%～0.29%;赤泥原样测量相对标准偏差 RSD(n = 10)为 1.28%,赤泥标准样品测量相对标准偏差 RSD(n = 3)为0.85%～2.72%.该方法灵敏度高、准确度和精密度好,常规实验室均可满足分析检测条件,可为赤泥高效脱碱和综合利用技术的开发提供可靠的分析检测支撑.

A semi-circular channel with connecting pipes is proposed to improve the overall heat transfer performance of the Printed Circuit Heat Exchanger (P CHE) used in the regenerator of the SCO2 Brayton cycle. Two semi-circular channels at the top and bottom, which are horizontally placed, were filled with hot and cold CO2, respectively. Thermophysical properties of SCO2 were solved by integrating NIST into the FLUENT 2020. A mesh number of 5.0M and the SST k-omega turbulence model were selected via comparison with experimental data. As results show, the overall heat transfer performance of the semi-circular channel with connecting pipes is improved by 1.1-2.5 times. The vortex structure induced by the connecting pipes increases turbulent kinetic energy and further enhances the heat transfer. This indicates that the connecting pipe proposed in this study is beneficial to activate heat transfer and reduce flow resistance.

Objective Viscosity and interfacial tension of fluid are key thermophysical properties, which influence the flow, as well as heat and mass transfer of fluid, and they are crucial parameters for studying and controlling multidisciplinary processes in the field of energy, chemistry, and life sciences. The surface light scattering (SLS) method can accurately access the viscosity and interfacial tension of Newtonian fluid in the full viscosity range. It has been rigorously supported by the theory and confirmed by experiments. Since the theory is developed in the frequency domain, it is necessary to convert the collected correlation data concerning the scattered light intensity from the time domain to the frequency domain by fast Fourier transform, and therefore a high signal-to-noise ratio of the time-domain data is crucial. For the sensing interfacial properties of fluid by the SLS method, it is necessary to guarantee both measurement accuracy and speed. In order to achieve the target, it is crucial to apply a small scattering angle and then correct the instrumental broadening effect. We thus develop an algorithm for the correction of the instrumental broadening effect in the frequency domain with an assumption of Gaussian distribution broadening instrumental function. We also check the theory with a low-viscosity refrigerant R1336mzz(Z) and high-viscosity fluid ethyl myristate with SLS apparatus at the small scattering angle. This paper aims to reduce the single-point measurement time of viscosity and interfacial tension of fluid by the SLS method to 2-5 minutes and will promote the further development of SLS sensors. Methods The frequency-domain data evaluation scheme of SLS is addressed in this paper. Under the assumption of a Gaussian intensity distribution of the laser beam, a modified frequency-domain model is established by considering the instrument broadening effect at the small scattering angle as well as the fluctuation-dissipation theory of capillary waves in the critical damping range. The spectrum model considers a series of collected wave vectors around the pre-defined q(0). Firstly, the intensity correlation data in the time domain at the specific q(0) are obtained by the SLS apparatus, and the zerochannel data are added by evaluating the fitted normalized intensity correlation function at tau = 0, and then the whole data are folded. The repeated data at the last channel are deleted, and a Fourier transform is applied to generate the frequencydomain data for subsequent fitting of the regression model. For the fitting process, an appropriate discrete component number d and integral interval variable n should be considered to represent the real wave vector distribution. Subsequently, the discrete spectrum model is fitted to the spectrum data, and the viscosity and interfacial tension are accessed with other thermophysical properties in the model as input data. In addition, the algorithm that considers multiple wave numbers simultaneously as well as the instrumental broadening effect is developed and manifests excellent performance. Results and Discussions Since the small angle measurement scheme is adopted in this paper, the signal-to-noise ratio is greatly improved, and the measurement time is significantly reduced to 2-5 minutes ( Fig. 2). In view of the instrument broadening effect at small angles, the weighted spectrum model [Eq. (11)] with Gaussian instrumental function is adopted. By collecting the thermophysical properties of the reference fluid R1336mzz(Z) at a temperature of T= 373. 05 K and incident angle Theta(i) of 1. 0-3. 2 degrees, the discrete component number d, integral interval variable n, and mean broadening constant Delta(q) are determined to be 10, 5, and (4507. 46 +/- 223. 34) m(-1), respectively (Fig. 5). The low-viscosity refrigerant R1336mzz( Z) and the high-viscosity ethyl myristate are used as two reference fluids to verify the correctness of the Gaussian modified spectrum model in two typical cases, where the capillary waves evolve as oscillatory damped modes far away from the critical oscillation point (Y' >> 1) and purely damped modes in the critical oscillation region (Y' -> 1), respectively. For low viscosity cases with Y' >> 1 ( Fig. 6), the interfacial tension and viscosity in both the time domain and frequency domain agree well for both large and small scattering angles after the instrumental broadening correction. For high viscosity cases with Y' -> 1 (Fig. 7), the viscosity data obtained by the frequency-domain method considering the dissipation effect in the bulk phases underneath surface waves are sufficiently larger compared with those obtained by the time-domain based method, especially close to the near-critical oscillation region. However, the data obtained by the frequency-domain approach are in good agreement with the literature values, and the instrumental broadening correction has no influence since the frequency omega(q) of surface waves tends to be zero at this time, and the spectrum broadening Delta omega(I) is negligible as shown in Eq. (7). Conclusions To improve the accuracy and speed of SLS measurement, we have applied small scattering angles and modified the line-broadening effect simultaneously. An algorithm is theoretically developed for correcting the instrumental broadening effect in the frequency domain with the assumption of Gaussian distribution of scattering light. With the reference fluids, the integral interval variable n and discrete component number d are obtained to be 5 and 10 to represent the distribution of the wave vectors, and the mean broadening constant.q is determined to be (4507. 46 +/- 223. 34) m-1 for the present SLS apparatus. We also check the theory with a low-viscosity refrigerant R1336mzz(Z) and high-viscosity fluid ethyl myristate with SLS apparatus, and the results show that the measuring speed is improved, and only 2-5 minutes for a single measurement point are required for the same accuracy as the large scattering angle scheme. This paper will facilitate the further development of SLS sensors and other applications in connection with complex interfacial property measurement.

The thermal and mutual diffusion coefficients of fluid working fluids are important transfer properties that characterize their heat and mass transfer in the field of refrigeration,petroleum,chemical and others. Reliable thermal and mutual diffusion coefficient data are normally necessary for design and optimization of the equipment and process. The thermal and mutual diffusion coefficients can be determined with different equipment. The dynamic light scattering method owns the advantages of measuring properties under equilibrium condition and in the non-contact and absolute way. However,it is still not an easy way to obtain the two properties simultaneously and reliably by the dynamic light scattering method. Therefore,the present study tries to understand the influence of sampling time,incident angle,viscosity, refractive index deviation and Lewis number Le in dynamic light scattering method on the reliability and accuracy of the method. In consideration of the difference of viscosity and refractive index,three binary systems of n-Hexane/ n- Decane,n-Hexane/n-Hexadecane and n-Hexane/ n- Decane at the defined molar fractions(0.50/0.50,0.06/ 0.94 and 0.85/0.15,respectively)are selected as reference fluids. The first and third systems have similar viscosity,but different refractive index difference of the components;the second and third systems have similar refractive index difference,but different viscosity. The measurement is performed in the saturated condition at different sampling times,incident angles and in a wide temperature range. Correlations are established based on the experimental data for both properties. The results show that the thermal diffusion coefficient and Le number decrease as the temperature increases,while the mutual diffusion coefficient increases as the temperature increases. The relaxation times of temperature fluctuations and concentration fluctuations of the binary system of n- Hexane and n- Decane with equal molar fractions satisfy a proportional relationship with the inverse of the square of the wave number,and the temperature and concentration fluctuations corresponding to the heat and mutual diffusion coefficients are verified to be consistent with the hydrodynamic model at the same time. The maximum fitting deviations between the measured thermal diffusivity and the calculated value of the fitting equation are 1.50%,1.10% and 1.00% respectively,and the average absolute deviations are 4.00%,0.34% and 1.95% respectively;the maximum deviations of mutual diffusion coefficient are 2.00%,5.62% and 1.00% respectively, and the average absolute deviations are 1.06%, 2.58% and 0.31% respectively. As the sampling time is 1.5 to 3 times of the relaxation time,the incident angle is between 8 degrees and 12 degrees,the system has lower viscosity and higher refractive index deviation (> 4%) and the Le value is 10 similar to 80,so it is possible to obtain both the thermal and mutual diffusion coefficients of the binary mixtures with an uncertainty of less than 5%. The dynamic light scattering experimental system developed in this study can be used to obtain the thermal and mutual diffusion coefficients of various complex binary systems simultaneously under the above defined conditions, providing a method for the study of diffusion in complex binary systems.

教材是教学活动的主要载体,也是人才培养的重要保障.基于新时代背景下应用型本科高校教材建设的新要求及内涵特征分析,建立了应用型本科"三新"(新时代、新工科、新形态)、"一融"(将学生价值塑造、知识传授和能力培养融为一体)的教材建设评价指标体系,以期对加强应用型本科高校教材建设,保障应用型本科人才培养质量提供参考.

In the present work, the liquid kinematic viscosity and surface tension of two low-GWP (Global Warming Potential) refrigerants as potential working fluids in heat pump, refrigeration, and organic Rankine cycles were investigated under saturation conditions by surface light scattering in the temperature range from (303.15 K to T-c). With the experimental data, a van der Waals type equation, and a polynomial equation with an additional term were proposed to correlate the surface tension and viscosity data, respectively. (C) 2022 Elsevier B.V. All rights reserved.

赤泥是氧化铝生产过程中产生的强碱性固体残渣,其环境污染大,安全隐患高,综合利用难,严重制约了氧化铝行业的可持续发展.赤泥作为水泥等生产原料是实现大规模综合利用的可行途径之一,但碱含量超标使得水泥制品出现开裂、鼓包和泛霜等现象,目前只能少量掺合使用,亟待系统开展赤泥脱碱研究.本文基于氧化铝生产工艺流程分析了拜耳法赤泥中各碱性物质的形成过程,综述了赤泥脱碱的方法与技术、热力学原理和动力学机理,分析了当前赤泥脱碱存在的问题,并展望了未来脱碱技术的发展方向,可为氧化铝行业赤泥脱碱和综合利用提供科学参考.

大容量高压车载储氢气瓶充氢过程的热力学响应特性是氢燃料电池汽车氢气安全充注亟需解决的关键问题.采用CFD模型,对70 MPaⅢ型车载储氢气瓶在不同长径比、充氢速率、气瓶初始压力、气源温度条件下充氢过程的热力学响应特性进行模拟.结果表明,在高压下氢气不可视为理想气体;重力对充氢过程的影响不能忽略;容积100 L储氢气瓶的最佳长径比为3.55;气源温度对充氢过程的影响最为显著,其次是气瓶初始压力与充氢速率,与热力学分析获得的结论类似.

Thermodynamic diagrams of Na?S?Fe?H2O system were constructed to analyze the behavior of sulfur and iron in the Bayer process. After digestion, iron mainly exists as Fe3O4 and Fe2O3 in red mud, and partial iron transfers into solution as Fe(OH)3?, HFeO2?, Fe(OH)4?and Fe(OH)42?. The dominant species of sulfur is S2?, followed by SO42?, and then SO 32? and S2O 32?. The thermodynamic analysis is consistent with the iron and sulfur species distribution in the solution obtained by experiments. When the temperature decreases, sulfur and iron can combine and precipitate. Controlling low potential and reducing temperature are beneficial to removing them from the solution. XRD patterns show that NaFeS2·2H2O, FeS and FeS2 widely appear in red mud and precipitates of pyrite and high-sulfur bauxite digestion solution. Thermodynamic analysis can be utilized to guide the simultaneous removal of sulfur and iron in the Bayer process.

低共熔溶剂是一种类离子液体的绿色溶剂,具有低饱和蒸汽压、低熔点、无毒、可降解以及价格廉价等优势,被广泛应用于科学研究和工程应用.其理化性质,如密度、黏度以及晶格结构等是开发具有特定功能溶剂及其应用的基础.本文采用分子动力学模拟的方法,利用GAFF力场计算了氯化胆碱类低共熔溶剂在293.15～353.15 K下的密度和黏度,与文献实验值的平均绝对偏差分别为0.30％和6.19％,显示出较好的一致性.同时在分子水平上,本文利用径向分布函数分析了不同体系内的结构分布以及氢键网络的形成,发现了低共熔溶剂中存在的大量氢键网络主要由Cl原子和羟基上的H原子相互作用形成的.且它们间的相互作用随着温度的升高而减弱,随着氢键供体烷基链长度的增加而增强.本文工作有助于进一步研究低共熔溶剂的组成、结构与其物理性质间的作用机制.

This study is conducted to solve the problem of large measurement errors in the critical oscillation region by the surface light scattering method and explore the ways to apply this method to measure the viscosity of Newtonian fluids in the full viscosity range. To this end, we correct the instrumental broadening effect of small angles in surface light scattering and establish the frequency- domain dispersion equation of surface waves that can precisely describe the full viscosity range of Newtonian fluids considering the dissipation effect of the bulk phases of surface waves at the gas-liquid interface in the near- critical oscillation region. The discrete fast Fourier transform is adopted to transform the time-domain correlation data into the frequency-domain data. A multivariate frequency- domain-based fitting algorithm is developed to ensure the accurate determination of the viscosity and surface tension in any viscosity range and give the uncertainty of statistical significance. This study provides the absolute viscosity measurement theory, method, and system of surface light scattering for full-viscosity-range Newtonian fluids.

研究单级氢气充注时,氢气充注速率、初始温度和压力对氢气终了温度的影响.通过调用NIST REFPROP中标准氢状态方程,模拟氢气在充注过程温度、压力、充注率等参数的变化.设计和模拟两级和三级氢气充注系统.结果表明:多级充注时,存在最佳的中间压力,使得充灌终了氢气温度最低,且增加级数可降低终了氢气温度.最后,对多级充注系统的能耗进行分析,结果表明随着级数的增加,系统的总能耗降低.