石墨电极生产用黏结剂沥青性能研究

分别对2种不同种类的石墨电极生产用黏结剂沥青进行性能测试,对比分析其质量性能差异;采用OM和FT-IR对原料沥青进行了微观形貌与组织结构的表征;采用TG曲线对用2种沥青制备的生坯进行热失重分析,为焙烧工艺曲线的制定提供参考依据。     

石墨电极用黏结剂沥青生产新工艺

黏结剂沥青的相关指标影响石墨电极的质量,为提高石墨电极的产品质量,需开发出更适合石墨电极用的黏结剂沥青.本文通过对比各种黏结剂沥青的生产工艺,研发出一种带循环比的管式炉聚合-真空闪蒸新工艺,用新工艺生产的黏结剂沥青和宝舜针状焦进行试验,经压型、焙烧、石墨化后的试体各项化验指标要优于宝舜其他工艺生产的黏结剂沥青.为提高整...     

煤沥青材料的应用及其发展前景

煤沥青分为低温、中温、高温煤沥青。介绍了煤沥青的种类与性能,论述了中温煤沥青作为基础材料用作黏结剂、浸渍剂、碳纤维、涂料,道路沥青等的应用,讨论了煤沥青用作石墨电极、电炭、防腐材料、结构材料、燃料油以及在道路沥青方面的发展前景。     

浸渍剂沥青和黏结剂沥青渗透性对比研究

选择两类具有相近流变性能的黏结剂沥青和浸渍剂沥青,模拟炭材料的微孔分布测定了两类沥青的渗透率,对比研究了浸渍剂沥青和黏结剂沥青的渗透性能差异。结果表明,浸渍剂沥青的渗透性能远优于黏结剂沥青,浸渍剂沥青的渗透率为黏结剂沥青相应值的3.54~22.13倍,两类煤沥青的渗透性差异是由于其QI含量不同造成的,浸渍剂沥青极低的QI含量(0.2%以下)大大降低了煤沥青向多孔滤材中的渗透阻力,为提高浸渍效果创造了有利条件。     

依据焦炭吸附性计算石墨电极工作配方中沥青加入比例

石墨电极生产中对沥青黏结剂加入比例要求十分严格,沥青量过大或过小都会造成生坯电极质量下降。如何准确地控制沥青量方面,炭素行业采取了多种方法进行判断,如测试糊料的挥发分,糊料的延伸率等,生产中还可以根据挤压压力大小,电极表面光滑状况、生坯内部是否存在"内分"等缺陷,间接判断沥青量是否合适。本文根据焦炭对变压器油吸附性测试结果,利用Excel表的强大计算功能,以计算待求配方的沥青比例为目的进行数学计算,并简述了其计算过程。     

超高功率石墨电极生产用炭糊料热解缩聚行为研究

通过TGA对超高功率石墨电极生产用炭糊料的热失重过程进行了研究,分析了炭糊料的热解缩聚特征,并对炭糊料和黏结剂煤沥青的热解缩聚行为进行了对比分析.结果表明,炭糊中煤沥青热解挥发过程不同于单体煤沥青,骨料针状焦的存在使黏结剂煤沥青易发生缩聚反应,从而有利于煤沥青稠环芳烃分子缩聚成焦,从而提高了黏结剂煤沥青的结焦值.     

一种沥青活化剂在中温沥青中的应用

本文从理论到实践介绍了用硬脂酸作为中温沥青的调节剂，能够降低沥青软化点和粘度，提高焙烧品的残炭率，以达到提高石墨电极的体积密度，降低电阻率，降低CTE以及石墨电极接头不足重率的降低。     

环氧改性沥青对沥青混凝土路面性能的影响

通过对比使用环氧改性沥青前后沥青混合料样品强度的变化等试验方法,评价环氧改性沥青对沥青混凝土耐久性和疲劳寿命的影响,以及环氧改性沥青作为沥青黏结剂的性能.结果表明:加入环氧改性沥青的沥青混合料拉伸强度明显高于对照组,并且其强度随着环氧沥青质量分数的增加而增加.此外,四点弯曲试验结果表明,环氧改性沥青可有效减少试样梁的挠度,从而改善沥青混合料的抗疲劳性.另外,采用在中间层加入环氧改性沥青的试验方法表明,使用环氧改性沥青作为黏结剂可改善两层之间的黏合强度.     

桥面铺装用环氧沥青混合料的制备及其性能研究

本文首先选取了环氧沥青作为胶凝材料，制备了OGFC4.75和OGFC13两种沥青混合料。然后对其进行了渗透性能实验、摆锤实验、动摩擦系数实验和吸声系数实验，并与两种常见的混合料进行了对比实验。结果表明，大粒径的OGFC级配混合料具有较好的透水性，PG64混合料的透水性略好于环氧沥青黏结剂；环氧沥青黏结剂配制的混合料提供的路面防滑性能优于PG64沥青黏结剂，减少骨料公称最大尺寸可提高路面的防滑性能；吸声系数测试结果表明，环氧沥青黏结剂有利于提高混合料的降噪性能。     

改质沥青及其在石墨电极生产中的应用

本文简单介绍了国内改质沥青的生产方法和实物性能、对改性沥青的性能的评价方法、改 质沥青用作石墨电极粘结剂时的工艺特点以及国内外生产实例。目的在于为炭素厂试用改质沥青作为石墨电极生产用粘结剂提供参考。     

Carbonization of pitch

An overview is presented of the many factors which influence the process of carbonization of pitch and hence the properties of pitch cokes. The controlling factors include type of starting material, the industrial process of carbonization, the role of quinoline-insoluble material and carbonization conditions. Several coke parameters are studied and related to the carbonization process by multiple regression analysis. Kinetic data are presented together with a schematic model of coke formation.     

Thermooxidation of coal tar pitch with the return of pitch distillates

The thermooxidation of moderate-temperature coal tar pitch with the return of pitch distillates is investigated, in conditions such that high-temperature grade-C pitch is obtained. Gas-liquid chromatography shows that the content of polycyclic aromatic hydrocarbons included in the list published by the United States Environmental Protection Agency (EPA) is not significantly different in the pitch samples before and after oxidation.     

煤焦油沥青添加废聚丙烯塑料制备改性中间相沥青

煤焦油沥青的甲苯可溶物中添加废聚丙烯塑料,对生成中间相的可溶性、共熔性、流动性、分子结构的变化进行了研究。结果表明,可溶性中间相沥青的含量从22%提高到52%,并且中间相沥青的光学结构从中间相含量为74%、内含各向同性相的粗镶嵌结构改善为中间相含量为100%的广域融并体。中间相的表观黏度分析显示添加废聚苯丙烯塑料在整个热处理过程中由于共熔效应的增强,降低了沥青基质的表观黏度,并且中间相沥青从触变性变为非触变性。红外和核磁共振分析表明通过添加废聚苯丙烯塑料,中间相沥青吡啶可溶物发生烷基增多的现象,出现较多的α取代亚甲基结构。而X射线衍射结果显示在添加废聚苯丙烯后由于烷基的增多,使芳香平面分子堆积变好。     

Enhanced oxidation performance of pitch fibers formed from a heterogeneous pitch blend

The oxidation performance of heterogeneous pitch fibers formed by blending a coal tar-derived isotropic pitch (IPc) and a naphthalene-derived mesophase pitch (MPn) was studied. The role of IPc in affecting the oxidation performance of such heterogeneous fibers was illustrated. The IPc spherical domains distributed in the MPn matrix facilitate the reduction of oxidization time and the decrease of the gradient of oxygen distribution. As such, the MPn/IPc blends have been demonstrated to be a feasible approach for reducing the oxidation difficulties in producing large diameter carbon fibers. Further improvement on the oxidation efficiency and the suppression of deep stabilization in large diameter pitch fibers were observed, when the blend precursors were oxidized in pure oxygen atmosphere.     

A thermoanalytical study of the co-pyrolysis of coal-tar pitch and petroleum pitch

Four pitch blends were prepared at laboratory scale by mixing a coal-tar pitch and a petroleum pitch in several proportions (CTP:PP 85:15, 70:30, 55:45 and 40:60). Single pitches and blends were characterized by standard procedures, infrared spectroscopy and size exclusion chromatography. Pyrolysis behaviour and interactions between the two pitches in the blends were studied by thermogravimetric analysis (TG/DTG) and differential scanning calorimetry (DSC). The results show that blending does not alter the composition of pitches. However, the TG/DTG curves reveal that coal-tar pitch and petroleum pitch interact actively during pyrolysis, modifying the temperature of initial weight loss and the temperature of the maximum rate of weight loss. Primary quinoline-insoluble particles present in coal-tar pitch and transferable hydrogen seem to be the main factors responsible for these modifications. The DSC curves show that the presence of coal-tar pitch in the blends reduces the reactivity of the petroleum pitch and shifts the exothermic peaks observed at the temperature of the cracking/polymerization reactions (>400 °C) to lower temperatures.     

Chemistry of pitch carbonization

The conversion of pitch to carbon is a complex process encompassing a multitude of physical and chemical transformations among the many pitch components. Studies on both individual aromatic compounds and pitches have shown that polymerization through loss of side chains and hydrogen is the main chemical reaction. Molecular rearrangements are also prevalent. A continual increase in molecular weight through polymerization and loss of low molecular weight volatiles results in the transformation of pitch to mesophase, coke and ultimately carbon. Stable free-radicals are formed during both the polymerization and rearrangement processes. These various aspects are reviewed to develop a general mechanistic sequence for pitch carbonization.     

High-temperature synthesis of pitch

The heat treatment of the anthracene fraction of coal tar under pressure is considered. In the production of synthetic pitch, the duration of the process is varied from 10 to 80 min, at a temperature of 500°C and a pressure of 3 MPa. Kinetic data for the formation of γ and α₁ fractions show that the polycondensation of the γ fraction is of second order, while the formation of the α₁ fraction is of zero order. Pitch obtained with holding for 10–40 min does not contain the α₁ fraction. Extending the process beyond 30 min does not affect the removal of heteroatoms. IR spectroscopic data indicate that dealkylation predominates for the first 40 min. Then the process slows, and compaction develops.