煤泥水浓度偏高原因分析及处理技术

煤泥水浓度是影响脱介效果和精煤产品质量的重要因素,在指导分选生产中起着重要作用。以山西焦煤西山煤电屯兰选煤厂煤泥水浓度偏高情况为例,分析了高频筛回收效果差、絮凝剂添加不科学、浓缩机溢流大、重介系统筛板、筛篮跑粗等因素是影响煤泥水浓度偏大的主要原因。针对上述问题提出控制浓缩机溢流电流在280~310 A,絮凝剂配制成0.1%溶液;降低设备底煤厚度等技术方案。改造后,选煤厂煤泥水质量浓度低于13 g/L,提高产品产率,实现节能降耗,提高选煤厂的效率。     

Er3+掺杂氧氟锗硅酸盐玻璃的频率上转换研究

研究了基质玻璃成分对Er^3 掺杂氧氟锗硅酸盐玻璃上转换光谱和Raman光谱的影响,分析了氧氟锗硅酸盐玻璃中Er^3 的上转换发光机理。结果表明：通过975nm的激光二极管激发,在室温下同时观察到强烈的绿光(529,545nm)和红光(657nm)发射,分别是由于Er^3 的。H11/2→^4I15/2,^4S3/2→^4I15/2,和^4F9/2→^4I15/2跃迁,且均为双光子吸收过程。与545nm的绿光发射相比,657nm的红光发光强度比较微弱。随GeO2浓度的增加,基质玻璃的最大声子能量下降,导致无辐射跃迁几率降低,因此绿光和红光的发光强度都增强,但是其对绿光的影响大于红光。     

Visible-light-active titanium oxide photocatalyst realized by an oxygen-deficient structure and by nitrogen doping

A visible-light (vis)-active titanium oxide photocatalyst was prepared by a simple wet process: the calcination of the hydrolysis product of Ti(SO₄)₂ with ammonia using an ordinary electric furnace in dry air at 400 °C. The color of this photocatalyst was vivid yellow and absorbed light in the blue (400 nm) to bluish-green (550 nm) region exclusively. Its structure was characterized to anatase with oxygen-deficient stoichiometry by XRD and X-ray photoelectron spectroscopy. Nitrogen was also detected, but only in trace amounts. Using blue-light-emitting diodes as a light source, 540 ppm of acetone was decomposed within 36 h and a stoichiometric yield of CO₂ was obtained. From the results of the crystalline size D, it was found that vis-activity could be realized on polycrystalline particles and the grain-boundaries (GBs) are thought to be important, since oxygen vacancies are easily created in GBs, which could form a GB state. Finally, we concluded that oxygen-deficient sites formed in GBs are important to emerge vis-activity, and nitrogen doped in the part of oxygen-deficient sites are important as a blocker for reoxidation.     

Formulation effects on the distribution of pigment particles in paints

Modern water-borne paints are widely used in different areas of applications ranging from high-gloss lacquers to flat, scrub-resistant interior paints. From this point of view, the pigment volume concentration (PVC) is one key-parameter adjusting the desired application properties. In high-gloss paints, for example, a low PVC is required to accommodate the proper surface roughness to achieve a high gloss. Consequently, a high concentration of TiO₂ is needed to obtain a good hiding power at the same time. Flat paints nonetheless are highly filled due to cost reasons preferentially by CaCO₃ and the pigment binding capacity of the binder is crucial. In this work, paint formulations differing in PVC, and the type of binder or dispersing agent were investigated by various techniques concerning the distribution and aggregation of pigment particles, e.g. TiO₂. To get a detailed insight into the structure of the liquid paints and the corresponding dried paint films, suitable analytical tools were applied for characterization. The structure of the liquid paints was analyzed by remission light spectroscopy (RLS), disc centrifugation, cryogenic-replication transmission electron microscopy (Cryo-replica TEM) and cryogenic-scanning electron microscopy (Cryo-SEM). The pigment distribution in the corresponding dried paint films was examined by means of atomic force microscopy (AFM), TEM and RLS. The tendency of the TiO₂-pigments to form aggregates was found to depend on both: first on the type of binder used in the formulation and second on the employed dispersing agent. It is shown that only by adjusting the properties of the binder in combination with common dispersants, it is possible to get well-distributed TiO₂ particles within the paint. Correlation of application properties, e.g. gloss and blocking to the microscopic structure is presented.     

离子辐照条件下Ti3AlC2的损伤机理研究

研究常温下He离子辐照对Ti3AlC2材料形貌和结构的影响并对其机理进行了分析.采用能量为70 keV,剂量为1×1017ions/cm2,位移损伤峰值为16.4 dpa的He离子注入Ti3AlC2材料;发现Ti3AlC2材料辐照损伤和He离子浓度有关,随着He离子浓度增大,辐照损伤程度越大;Ti3AlC2材料经过He离子辐照后产生会有孔洞、凸起和氦气泡产生;与此同时,Ti3AlC2结构上发生ɑ相到β相的转变,并对Ti3AlC2材料的损伤机理进行分析.     

铷掺杂三元正极材料Li1-xRbxNi0.4Co0.2Mn0.4O2的制备及其电化学性能

采用共沉淀法制备了三元材料LiNi0.4Co0.2Mn0.4O2,掺杂不同比例铷进行改性,对其进行了结构表征,考察了其电化学性能. 结果表明,Li0.97Rb0.03Ni0.4Co0.2Mn0.4O2样品的结晶度较好,铷掺杂起到了稳定三元材料晶体结构的作用,有效改善了材料的电化学性能,5C倍率下放电比容量达130 mA?h/g.     

掺杂铁TiO2纳米微粒的制备及光催化性能

以钛酸四丁酯为前驱体,采用溶胶-凝胶法制备了Fe^3＋掺杂改性纳米TiO2光催化剂,通过纯TiO2和掺铁TiO2分别做光催化剂时甲基橙溶液在紫外光下的光催化降解试验发现,掺杂铁离子可以有效提高TiO2的光催化活性．结果表明：选用Fe^3＋掺杂量为0．05％,煅烧温度在500℃下得到的Fe^3＋-TiO2催化剂,在甲基橙溶液pH值为3,催化剂投加量为1g／L时,其光催化活性达到最佳效果。     

细粒金红石矿重选抛尾工艺研究

采用摇床抛尾工艺流程,可得到精矿产率49．26％、全钛品位4．79％、全钛回收率80．80％重选粗精矿。抛除尾矿量达50．74％,为浮选作业提供了有利条件。     

碘化物-碘酸盐体系离集指数计算式的修正

从1953年Danckwerts提出离集的概念到现在,微观混合研究已有50多年的历史．所谓微观混合是指分子尺度上的均匀化过程,即通过破碎和变形使未混合的液体微元尺度减小,再由分子扩散达到最后混合．由于缺乏足够的分辨率,以物理现象为基础的方法难以满足微观混合研究的需要,因此采用化学反应作为分子探头的化学方法就成了目前最常用的研究微观混合的方法．这些反应可以分为3类：