基于力测量法研究滑石的晶面各向异性

层状硅酸盐矿物滑石在解离时会形成具有明显性质差异的2种表面，滑石的晶面各向异性会导致矿物不同表面表现出不同的润湿性以及不同的电荷密度。通过原子力显微镜力（AFM）曲线测量以及经典DLVO理论计算，对滑石的非极性面和极性面进行深入研究，首先利用AFM力曲线测量和计算，得到不同pH值时氮化硅的电位值，利用AFM直接力测量法对符合粗糙度要求的滑石非极性面和极性面样品在10 mmol/L的KCl溶液中进行测量，得到不同pH值环境下的力曲线，通过DLVO理论拟合计算得到滑石非极性面和极性面的表面电位值。滑石的非极性面电位值在研究的pH范围内一直为负，且恒定，极性面电位值随pH升高而降低，零电点出现在pH=7.6左右。将计算得到的滑石表面电位与氮化硅之间的作用力拟合曲线与实际测得的作用力进行对比发现，计算值与测量值基本一致，拟合度较高。     

The improvement of the self-healing ability of MoSi2 coatings at 900–1200 °C by introducing SiB6

The brittleness of MoSi₂ ceramic and the thermal mismatch between MoSi₂ coating and C / C composite lead to brittle cracking of the coating at 900−1200 °C. This problem has been overcome in this studyby introducing submicron-SiB₆ into the coating. The pre-fabricated cracks and a kinetics model of hot-pressed SiB₆-MoSi₂ ceramic could quantitatively predict the glass growth and crack healing. As expected, enhancing temperature and SiB₆ content increased the growth rate of the borosilicate glass and the crack healing ability of MoSi₂ ceramic, which was ascribed to the lower oxidation activation energy and larger specific surface area of submicron-SiB₆. For the plasma sprayed coating, SiB₆ with submicron structure was benefit for cracking inhibition and formation of borosilicate glass during oxidation, reducing the oxygen permeability and the consumption of inner coating. Hence, the 15 % SiB₆-MoSi₂ coatings raised the protection times to 84 and 120 h at 900 and 1200 °C respectively, presenting favorable oxidation protective performance.     

Highly permeable macroporous cordierite ceramics with controlled microstructure produced by particle-stabilized emulsions with a reactive thermal treatment

Macroporous cordierite ceramics, comprising hierarchical microstructures, are produced by a method of particle-stabilized emulsions, combined with a followed reactive thermal treatment. The microstructure is tailored by altering sintering temperature and solid content in the emulsion templates. Pore throats generate in-situ by introducing magnesite in templates, in contrast to conventional methods, which use either surfactants or depending on thin film contact. Moreover, microstructural evolution of samples is studied by DTA/TG, XRD, and SEM analyses. The results of analyses show that the formation of much more pore throats is closely related to the release of gas from the raw materials and volume shrinkage. The optimal process conditions are a temperature of 1300 °C and a solid content of 30 vol.%. The as-prepared sample displays a nitrogen permeability of ∼1.8 × 10⁻¹¹ m². The method shows great promise for producing many other highly permeable ceramics using pore former agents in the emulsion templates.     

Structure and properties of TiC/Ti coatings fabricated on NiTi by plasma immersion ion implantation and deposition

A titanium carbide (TiC) nanostructured coating and Ti intermediate layer are fabricated on NiTi by plasma immersion ion implantation and deposition (PIII&D) to improve the surface properties. The chemical composition and structure are determined by X-ray diffraction, Auger electron spectroscopy, scanning electron microscopy, and atomic force microscopy. Nano-indentation is used to evaluate the mechanical properties of the thin film and the biological characteristics are assessed by electrochemical measurement and soaking tests in simulated body fluids. Based on the potentiodynamic polarization and Ni release data after the polarization test, the Ti/TiC nanostructure coating has better corrosion resistance compared to the NiTi substrate and there is significantly less Ni ion release from the NiTi substrate into the simulated body fluids than the uncoated NiTi alloy.     

某复杂金多金属矿石选矿试验研究

吉尔吉斯斯坦某金多金属矿石中伴生多种有价元素,有用矿物嵌布状态复杂且嵌布粒度细。针对矿石性质,采用铜优先浮选—金钴混合浮选工艺流程,可初步实现该金多金属矿石中有价金属的有效分选。闭路试验可获得Au品位228.00 g/t、Au回收率12.19%,Ag品位974.00 g/t、Ag回收率37.71%,Cu品位27.590%、Cu回收率80.65%的铜精矿,以及Au品位65.00 g/t、Au回收率57.22%,Ag品位28.00 g/t、Ag回收率17.86%,Co品位0.5500%、Co回收率53.02%的金钴精矿。     

First-principles calculations of electronic structures and optical,phononic, and thermodynamic properties of monoclinic α-spodumene

To further the applications of spodumene in ceramic materials, we performed first-principles density functional theory calculations using a quasi-harmonic approximation to investigate the electronic structures and optical, phononic, and thermodynamic properties of monoclinic types of α-spodumene with C2 and P2₁ structures. The electronic structures of C2- and P2₁-spodumene including band structure and density of states, were observed to be similar. These spodumene can be treated as wide-direct-band-gap insulators with band-gap widths of 5.537 eV for C2 -spodumene and 6.335 eV for P2₁-spodumene. The optical properties of C2- and P2₁-spodumene indicated that both C2- and P2₁-spodumene were found to be optically anisotropic and they can be used for UV shielding in optical devices. Additionally, we investigated the phononic properties of these spodumene to explore their thermodynamic characteristics, and found that both types are dynamically stable.     

The formulation and use of mixed collectors in sulphide flotation

Mixtures of collectors have been widely used for many years in sulphide flotation, and a range of performance benefits have been reported for many different systems. The combinations of collector types have varied, as have the ratios that have been used. Synergistic effects have been obtained (greater than the sum of the parts) and in some cases the mechanisms of this improved behaviour have been identified. These benefits have been attributed to increased carrying capacity of the froth phase, faster kinetics, and more successful recovery of middling or coarse particles. It is the interaction between the various components of the mixed collector system, rather than the individual main effects, that dominate the performance benefits. The process benefits include increased paymetal recoveries and grades – as well as increased rates of recovery whilst using lower dosages of reagents. Various mechanisms have been reported and are discussed. These have been shown to affect different composition/liberation classes and sizes of mineral particles. In recent years, automated quantitative mineralogy and surface analysis technology such as ToF-SIMS have enabled the development of better information, to establish what aspect of the process has been affected. This has been successful mostly for use in a diagnostic capacity. Candidate selection for the mixed collector suite is presently based on experience and contextual knowledge. Predictive properties from these systems are a desirable future goal. Currently optimum combinations are preferably identified experimentally at laboratory scale prior to any plant trial. It is recommended that such laboratory work be performed using a factorial design with replicates and quality controls, such as may be delivered from High-Confidence Flotation Testing. The purpose of this paper is to summarise and review current theory and practice in the usage of mixtures of collectors in sulphide flotation – both in the application and in research in order to develop insights and guidelines to develop a methodology for use in a predictive capacity. A case study demonstrating this approach will be published at a later date.     

白铅矿的硫化电位控制浮选机理研究

以乙基黄药为捕收剂,硫化钠为硫化剂,通过单矿物浮选试验系统地研究了白铅矿浮选时硫化钠用量、硫化时间、搅拌条件、加药方式以及矿浆p H对硫化过程中矿物的浮游性、矿浆电位、硫离子电极电位的影响。采用多元回归方法建立了浮选回收率与硫化电位的数学模型,数学模型很好地反映了两者之间的关系。使用相关系数法分析了各因素对硫化电位的影响趋势及两者间的相关性。利用Matlab数学软件拟合出硫化电位与主要影响因子间的数学模型方程,再结合回收率与电位的数学模型,可以实现对硫化过程及时、合理的调控。     

Chinese red pepper (Zanthoxylum bungeanum Maxim.) leaf extract as natural antioxidants in salted silver carp (Hypophthalmichthys molitrix) in dorsal and ventral muscles during processing

Chinese red pepper (Zanthoxylum bungeanum Maxim.) leaf (ZML) extract contains high amounts of phenolic compounds possessing high total antioxidant capacity and hydroxyl, 1, 1-dipheny-2-picrylhydrazyl (DPPH) free radical scavenging activity. ZML extract was investigated as a natural antioxidant for the lipid stability of salted silver carp (Hypophthalmichthys molitrix) throughout salting and drying. Both dorsal and ventral muscles were examined for differences in moisture content, salt content, total lipid content, and degree of lipid oxidation. The hexanal content, Thiobarbituric acid reactive substances (TBARS) value, and lipoxygenase (LOX) activity in the ventral muscle were significantly higher than those of the dorsal muscle (p < 0.05). In the treatments with ZML extract, the hexanal content, the TBARS value, and the LOX activity were significantly lower (p < 0.05) during processing both in the dorsal and ventral muscles. The sensory qualities of processed salted fish could be improved with the amount of 0.030% extract in the dorsal muscle and 0.045% extract in the ventral muscle. These results showed that ZML extract can be a source of natural antioxidants and used as a food additive.     

Effects of Oxidation Curing of Polycarbosilane on Dielectric and Microwave Absorption Properties of PDCs‐SiC Ceramics

Polycarbosilane (PCS) was cured by oxidizing at different temperatures and pyrolyzed at 1000°C in vacuum. The dielectric properties of SiC ceramics were studied in X band. The ε′ and ε″ of SiC ceramics derived from oxidation‐curing PCS decreased to 4 and 0.35, respectively, which attribute to the decrease of free carbon content and order. SiC ceramic derived from PCS cured at 180°C showed that reflection loss was lower than ?10 dB in the frequency range from 8.2 to 11.3 GHz and the minimum value was ?26.7 dB at 9.6 GHz, which exhibits a promising prospect as microwave‐absorbing materials.