粉末涂层材料粒度测试的研究

采用干筛分法、 激光衍射法和扫描电子显微镜法测试了粉末涂层材料的粒度, 对比了不同方法的测试结果, 研究了粉末材料的形貌对粒度测试的影响。 结果表明： 干筛分法测试球形的粉末、 不规则形粉末、 片状粉末的粒 度分布具有较好的重复性; 三种方法测试的结果相差较大, 且粒度越大, 差异越大。     

Bioinspired Graphene Oxide Membranes with Dual Transport Mechanisms for Precise Molecular Separation

The implementation of membrane technology to replace or combine with energy‐intensive cryogenic distillation for precise separation of ethylene/ethane mixture proves an extremely important yet highly challenging task. Inspired by the hierarchical structure and facilitated gas transport of biological membranes, a highly selective ethylene/ethane separation membrane is explored through the fixation of a silver ion carrier and the impregnation of ionic liquid within 2D nanochannels of graphene oxide laminate, where plenty of ethylene‐permeating in‐plane nano‐wrinkles and ethylene‐facilitated plane‐to‐plane nanochannels are constructed. By virtue of synergistic effects of molecular sieving and carrier‐facilitated transport, an unprecedented combination of high ethylene permeance (72.5 GPU) and superhigh ethylene/ethane selectivity (215) is achieved, out‐performing currently reported advanced membranes. Moreover, molecular dynamics simulations verify a favorable membrane nanostructure for fast and selective transport of ethylene molecules. This bioinspired approach with dual transport mechanisms may open novel avenues to the design of high‐performance membranes for precise molecular separation.     

MXene Materials for Designing Advanced Separation Membranes

MXenes are emerging rapidly as a new family of multifunctional nanomaterials with prospective applications rivaling that of graphenes. Herein, a timely account of the design and performance evaluation of MXene-based membranes is provided. First, the preparation and physicochemical characteristics of MXenes are outlined, with a focus on exfoliation, dispersion stability, and processability, which are crucial factors for membrane fabrication. Then, different formats of MXene-based membranes in the literature are introduced, comprising pristine or intercalated nanolaminates and polymer-based nanocomposites. Next, the major membrane processes so far pursued by MXenes are evaluated, covering gas separation, wastewater treatment, desalination, and organic solvent purification. The potential utility of MXenes in phase inversion and interfacial polymerization, as well as layer-by-layer assembly for the preparation of nanocomposite membranes, is also critically discussed. Looking forward, exploiting the high electrical conductivity and catalytic activity of certain MXenes is put into perspective for niche applications that are not easily achievable by other nanomaterials. Furthermore, the benefits of simulation/modeling approaches for designing MXene-based membranes are exemplified. Overall, critical insights are provided for materials science and membrane communities to navigate better while exploring the potential of MXenes for developing advanced separation membranes.     

对新流行词“话语权”的若干思考

“话语权”一词近几年来在中文媒体上出现后被广泛沿用的过程中,在文辞表达上普遍存在着概念模糊、文理不通和逻辑混乱的现象。对此,作者通过分析指出其根本原因,在于该词并不具有可被确切把握和让人们达成共识的真实涵义。进一步从语言学和术语学的角度分别进行深入探索,其结果表明：“话语权”作为普通词语不符合组词规则;对于相关学科（如“传播学”）来说,它也不能成为可以表达某个特定概念的名实相符的专业术语。文章最后还分析指出了该词近几年间之所以能成为”新流行词”的几方面原因。     

Combination of Different Size Distributions for Mineral Particles by Applying Experimentally Determined Apparent Mean Shape Factor

As is well known, the behavior of systems of fine particles is strongly dependent on the size of the individual particles, and the size effects become increasingly important as the particles become progressively smaller. This study covers two different size analysis techniques, sieving and laser diffraction measurement, and constructs whole size distribution for different mill (ball and rod) products of some industrial minerals: barite and quartz minerals. A smooth overlap of corrected laser diffraction size distribution and sieve size distribution was obtained by applying the particle size with the apparent mean shape factor shifting to the right side of the curve for the rod-milled barite and ball- and rod-milled quartz. The apparent mean shape factors determined from the corrected particle size distributions were found to be 1.02 and 1.39 for ball- and rod-milled barite and 1.29 and 1.25 for ball- and rod-milled quartz, respectively. The results indicate that the ball-milled products of barite mineral have more regular (rounder in shape) particles than those of rod-milled barite, but there are not significant differences between the shape factors of ball- and rod-milled products of quartz mineral, i.e., both of them have irregular particles that deviate from spherical shape, as evident from the SEM pictures taken.     

薛湖选煤厂筛分作业问题分析与改造

分析了薛湖选煤厂原煤性质,指出了该厂筛分作业在实际生产中所存在的问题,筛分作业效率不高影响了选煤厂后续生产,导致精煤产率降低。通过技术改造,用香蕉筛替代博后筛后成功解决了这些问题。     

废镁砖中贵金属综合回收技术创新与实践

针对金银转炉拆迁废镁砖中金银含量较高、脉石主要为氧化镁等特点,在生产实践中综合考虑投资成本、可操作性等情况,在小型选矿试验基础上,经技术研究与论证,提出干磨—筛分分选—细粒浮选工艺,即干磨后试样采用高频振筛,将粗粒金银颗粒预先筛分回收,再采用浮选对细粒金银进一步回收,实现了废镁砖中金银的梯级回收。工业生产获得了金银精矿含金674.91 g/t,含银9.14%,金回收率为90.37%,银回收率为88.02%的较好指标,且具有较好的经济效益。     

冻融循环与硫酸盐侵蚀耦合作用下湿筛混凝土超声波波速与抗压强度的关系

为研究超声波对冻融循环与硫酸盐侵蚀耦合作用下水工混凝土的检测效果,开展了冻融循环与硫酸盐(5%Na2SO4)侵蚀耦合作用下湿筛混凝土试验,利用超声波检测仪测试分析了波速随冻融循环次数的变化规律及波速与抗压强度之间的关系。结果表明,波速随冻融次数的增加而逐渐减小,尤其是200次以后急剧下降,波速与冻融次数之间呈抛物线关系,并与抗压强度密切相关,可以反映出湿筛混凝土的抗冻性能变化,为运用波速评价冻融循环与硫酸盐侵蚀耦合作用下湿筛混凝土的损伤性能提供了理论依据。     

An Innovative Device for Quantification of Percolation and Sieving Segregation Patterns–Single Component and Multiple Size Fractions

ABSTRACT

Segregation occurs during most particulate materials-related unit operations including mixing, conveying, discharging, filling, and compaction. A redesigned second-generation primary segregation shear cell (PSSC-II) was fabricated to simulate and quantify percolation and sieving mechanisms-based segregation. Several binary mixtures were tested to quantify the effect of size ratios and absolute size. The constituents of binary mixtures studied were spherical glass beads. Three binary size ratios, 4:1, 6:1, and 8:1, were tested. For a given size ratio, three different absolute coarse (710–850, 1000–1200, and 1400–1700 μm) to fine particle sizes were studied. The experimental results showed that the PSSC-II was capable of quantifying segregation potential for various materials. Several physical parameters such as segregation rate (SR), phase of segregation rate (PSR), distribution of segregation rate (DSR), maximum segregation rate (MSR), and normalized segregation rate (NSR) were created to describe the quantity of segregation to a certain level. It was concluded that: (1) Generally, the segregation rates increase with the increase in size ratio. A linear relationship between NSR and size ratio exists for glass beads (R² = 0.99). (2) Segregation rate also increases with absolute size. NSR increases linearly with absolute size for glass beads (R² = 0.99). Furthermore, a quantitative relationship exists between certain size ratios and segregation rates, i.e., while size ratio increased two-fold from 4:1 to 8:1, the NSR increased approximately six-fold. (3) The largest magnitude of the NSR occurred where both absolute size and size ratio were at their largest values. (4) The DSR for the binary mixture of glass beads was mainly concentrated in the center region of the shear box for larger size ratios such as 8:1 and 6:1, whereas, for smaller size ratios such as 4:1, the DSR is approximately uniformly distributed. (5) Both duration of lag phase (DLP) and duration of acceleration phase (DAP) decrease with increase in size ratios and in absolute sizes. The smaller the DLP and DAP, the larger the MSR.     

动态模拟在循环水配方筛选及日常管理中的应用

动态模拟作为一种先进的化工流程模拟技术,极具科学性和可靠性。本文就循环水动态模拟装置在循环水配方筛选及日常管理中的应用作了认真研究和系统总结。