六偏磷酸钠对蛇纹石的分散机理研究

通过红外光谱、分散度、ζ电位及吸附量测定, 研究了六偏磷酸钠对蛇纹石表面性质的影响, 并利用DLVO 理论就六偏磷酸钠对蛇纹石的分散行为进行解释。研究结果表明:六偏磷酸钠在蛇纹石表面的吸附量较小, 但六偏磷酸钠作为高分子化合物, 仍足以增大蛇纹石表面电位的绝对值, 提高了粒间静电排斥作用能, 这应是六偏磷酸钠分散蛇纹石的主要作用形式。     

信阳蛇纹石矿资源调查

对信阳地区蛇纹石矿资源的分布状况、储量、特征、组成和开采应用情况等进行了简要介绍,同时对它的未来开发方向提出了一些建议。     

多楔带附件驱动系统旋转振动方程的通程式方法

建立了单根多楔带附件驱动系统的旋转振动方程的通程化方法,以适用于不同布置形式的单根多楔带附件驱动系统的旋转振动特性计算。在此基础上,开发了一个单根多楔带附件驱动系统旋转振动特性的计算程序,并利用该程序对两个不同布置形式的多楔带附件驱动系统的旋转振动特性进行了计算。计算得到了这两个不同布置形式的多楔带附件驱动系统的固有频率、带的稳态张力、轮和张紧臂的角度波动、带段的动态张力和最大轮毂载荷等。将部分计算值和实测值进行对比,验证了本文所建立的通程式方法的可行性。     

Mechanisms of surface charge development of serpentine mineral

The electrokinetic behavior and surface dissolution of serpentine mineral were studied through Zeta potential measurements, dissolution experiments and X-ray photoelectron spectroscopy. The results show that serpentine has an iso-electric point (IEP) of 11.9, which is higher than that of other phyllosilicate minerals. Dissolution experiments show that the hydroxyl is easy to dissolve with respect to the magnesium cations in the magnesium oxide octahedral sheet. As a result of hydroxyl dissolution, the magnesium ions are left on serpentine surface, which is responsible for serpentine surface charge. The removal of magnesium ions from serpentine surface by acid leaching results in a decrease of serpentine IEP. Therefore, it has been clearly established that the surface charge developed at the serpentine/aqueous electrical interface is a function of the serpentine surface incongruent dissolution.     

Biodiesel production in a serpentine minireactor—Effect of flow distribution

The present work aims to find out the influence of flow pattern on pressure drop and fatty acid methyl ester (FAME) yield in a reactive system. Experiments are carried out with Jatropha oil and methanol by using potassium hydroxide (KOH) as catalyst for biodiesel production in two serpentine minireactors made of glass capillary of 2‐mm internal diameter. One is having a circular cross section, and the other is annulus. Slug flow, slug with droplet flow, and dispersed flow are observed in both the reactors. Effects of flow distribution on pressure drop and FAME yield have been studied. FAME yield of 98.5% is observed in both reactors for a molar ratio 20 (methanol to Jatropha oil), and the time for this yield in the first reactor is 16.6 minutes and that for the second reactor is 7.7 minutes. Higher yield also resulted in lower pressure drop due to lower viscosity of biodiesel in comparison with oil.     

Enhancing under-rib mass transport in proton exchange membrane fuel cells using new serpentine flow field designs

New flow field configurations are developed to improve the performance of polymer electrolyte membrane fuel cells (PEMFCs). The developed designs aim to uniformly distribute the reactants over the reaction area of the catalyst layer surface, boost the under-rib convection mass transport through the gas diffusion layer, decrease the water flooding effect in the gas diffusion layer-catalyst layer interface, and maintain the membrane water content within the required range to augment protonic conductivity. To evaluate the performance parameters of a PEMFC, a comprehensive three-dimensional, two-phase mathematical model has been developed. The model includes the charge transport, electrochemical reactions, mass conservation, momentum, energy, and water transport equations. The results signify that the improved flow field patterns attain a considerable boosting of the output power, the under-rib convection mass transport, improvement of the reactant distribution over the catalyst layer surface and decline of the liquid water saturation in the gas diffusion layer-catalyst layer interface. The developed configurations achieve a higher power density of 0.82 W/cm² at a current density of 1.74 A/cm², compared to the standard serpentine configuration, which attains about 0.67 W/cm² at a current density of 1.486 A/cm².Accordingly, the develop configurations demonstrate a 22.6% enhancement in power density.     

有机热载体炉蛇形管失效原因分析

采用金相检验、力学性能测试、导热油化验等方法对某有机热载体炉发生火灾的原因进行了分析。结果表明：该事故的原因为使用的导热油标号过低,导致导热油在蛇形管内碳化、结焦,蛇形管过热,并产生蠕变裂纹,最终强度不足发生爆管。     

Separation of Chromite from Serpentine in Fine Sizes using Magnetic Carrier

In this study, possible separation of chromite from serpentine in fine sizes using a magnetic carrier was investigated as a function of pH, dodecylamine (DDA) dosage, and amount of magnetite. First, the zeta potentials of minerals were determined in the absence and presence of DDA, and then magnetic carrier experiments were performed in conditions based upon the zeta potential results. Experiments revealed that chromite could be separated from serpentine with a 96.8% recovery under the experimental conditions of 4 x 10^?4 M DDA, 25 mg magnetite, and at pH 12. In the case of artificial mixtures of chromite and serpentine minerals, chromite concentrate containing 49.7% Cr₂O₃ was obtained with 82.8% recovery from a feed containing 27.00% Cr₂O_3. As a result of FTIR studies, physical adsorption of DDA on minerals was confirmed. It was also found that DDA adsorption on chromite was higher than those of serpentine and magnetite. FTIR studies performed with chromite+magnetite and serpentine+magnetite mixtures revealed that DDA adsorption on serpentine declined significantly while DDA adsorption on chromite slightly increased.     

中国三个产地蛇纹石玉的地质背景及宝石学特征

辽宁省岫岩县、山东省泰安县和青海省祁连县是中国市场上蛇纹石玉最主要的三个产地,不同产地的矿床特征及所产蛇纹石玉在外观、化学成分和红外光谱等方面存在较大差异。本文综合前人的研究成果,从地层、构造、矿体、形成时期、成因等角度对三个产地蛇纹石玉矿床的地质特征进行了归纳总结;通过收集三个产地蛇纹石玉的常规宝石学特征、电子探针分析数据及红外光谱测试数据,对这三个产地蛇纹石玉的基本宝石学性质、化学成分和红外光谱图进行了对比分析,总结了三个产地蛇纹石玉的鉴别特征。三个产地的蛇纹石玉在颜色、光泽、透明度、内含物等方面表现出不同的特征,在化学成分、微量元素、红外光谱特征方面也有明显的差异,这些鉴别特征在一定程度上都可以辅助判断产地。此外,蛇纹石玉的颜色与Fe元素有关,Fe含量越大,绿色越深。