煤沥青粉填充环氧防腐涂料的制备

主要介绍了煤沥青粉填充环氧防腐涂料的制备方法。以环氧树脂、煤沥青粉、脱晶蒽油为主要原料,配以滑石粉、铁红作为颜色填料,以低分子聚酰胺作固化剂,分别探索了环氧树脂总用量、不同种类环氧树脂的比例、煤沥青粉与脱晶蒽油的比例、不同粒度煤沥青粉等因素对于环氧防腐涂料的固化时间、附着力、耐冲击强度、硬度、耐酸碱性的性能影响。通过试验设计获得制备该防腐涂料的最佳工艺条件。     

对苯二甲醛对煤沥青流变性能的影响研究

为了探讨对苯二甲醛(TPA)对煤沥青流变性能的影响,采用旋转黏度计测定了煤沥青及TPA改性的煤沥青的表观黏度,研究了表观黏度与温度的关系;采用示差扫描量热法(DSC)研究了煤沥青和TPA改性的煤沥青的热行为.结果表明,TPA改性的煤沥青的黏度与温度的关系曲线呈现W型,在200～225℃之间处于低黏流区,表观黏度值约200～400 MPa.s,可以作为浸渍剂煤沥青使用;TPA改性的煤沥青在高于225℃时表观黏度值迅速上升;TPA改性的煤沥青在低黏度区域具有较低的活化能,这对煤沥青的浸渍工艺有益.图6,表2,参11.     

中温煤沥青悬浮法制备球形活性炭的研究

以软化点为85 ℃、0.30～0.45 mm的中温煤沥青颗粒为原料，采用悬浮法制备沥青球，采用混合氧化法（HNO3液相氧化和O2气相氧化）对沥青球进行不熔化处理. 不熔化沥青球经过炭化、CO2活化法制备沥青基球形活性炭. 采用SEM、TG/DTG、FT-IR对沥青球进行表征. 结果表明，采用悬浮法制备的沥青球表面光滑、平均球形度0.981、粒径分布集中，0.30～0.45 mm的沥青球质量占比超93%. 活化温度940 ℃，保温6 h制得的沥青基球形活性炭的BET比表面积为1 545 m2/g、微孔率为75.30%.     

煤沥青改性中间相炭微球制备高密高强石墨的研究

为解决低粘结组分中间相炭微球(MCMB)自烧结性较差的问题,采用热分析和扫描电镜等表征方法,研究了煤沥青种类对改性MCMB粉体烧结性能及其所制备的石墨材料性能的影响.结果表明,采用溶液混合法可在MCMB粉体(D50=23μm)表面均匀包覆一层煤沥青,并显著提高了低粘结组分MCMB粉体的烧结性能.以改性MCMB粉体为原料经等静压成型、焙烧和石墨化处理所制备的石墨材料均匀致密,抗折强度明显高于以未经改性处理的MCMB粉体为原料制备的石墨材料(22MPa),并按改性用高温沥青、改质沥青和中温沥青的顺序依次升高,分别为27.7 MPa、42.7 MPa和56.9 MPa.     

低喹啉不溶物含量煤沥青的研制及其炭化行为探讨

以煤焦油为原料，选用正已烷和苯混合溶剂，通过溶剂革取分离和蒸馏，制备得到低喹啉不溶物含量净化煤沥青。在不同条件下对所制取的低喹啉不溶物含量煤沥青进行炭化热处理，分析了净化沥青的炭化行为。将净化沥青炭化产物制成光片，观测其显微组织结构特征和中间相球体的生长发育，判定作为针状焦和碳纤维原料的可能性。     

山西几种煤沥青性能的研究

本文对山西三种不同类型的煤沥青进行了溶剂配制,用示差精密热分析仪研完了它们的热行为;在热台显微镜下观察了它们在热反应过程中的软化熔融温度、中间相的生成和变化温区及显微结构的变化。结果表明:太钢煤沥青在生成中间相的过程中有良好的热行为,有可能成为制备碳纤维的良好原料。     

炭黑对煤沥青热解缩聚行为的影响

通过TG对煤沥青和煤沥青/炭黑复合物热失重过程的研究,分析了两类煤沥青物料的热解缩聚特征,并对煤沥青和煤沥青/炭黑复合物的热解缩聚行为进行了对比.结果表明,煤沥青/炭黑复合物中煤沥青热解挥发过程不同于煤沥青,炭黑的添加使煤沥青易发生缩聚反应,有利于煤沥青稠环芳烃分子缩聚成焦,从而有效地提高了煤沥青的成焦率.     

煤沥青热解缩聚行为的研究

通过TGA对煤沥青的热失重过程进行了研究,分析了煤沥青的热解缩聚特征,并对中温沥青和改质沥青热解缩聚行为进行了比较。     

3种煤沥青炭微观结构及其性能的对比研究

将高温煤沥青、中温煤沥青、浸渍剂沥青在常压下炭化,经2 300 ℃石墨化处理,制备3种煤沥青炭.利用扫描电子显微镜(SEM)观察煤沥青炭的显微结构;采用X射线衍射法(XRD)检测煤沥青炭的石墨化度;通过氮吸附法测定煤沥青炭的比表面积(SBET);采用热重(TG/DTG)分析手段测试并分析煤沥青炭的氧化性能.研究结果表明:煤沥青的族组分影响煤沥青炭的形貌,喹啉不溶物含量低有利于流线型结构的形成;高温煤沥青炭微观结构主要以流线型和镶嵌型为主,中温煤沥青炭和浸渍剂沥青炭以流线型为主,但浸渍剂沥青炭流线型结构取向性好;煤沥青炭中含有流线型结构越多,则其石墨化度越高,比表面积越低;煤沥青炭的氧化失重主要发生在700～900 ℃,浸渍剂沥青炭的抗氧化性能最好.     

无烟煤改性中温煤沥青的组分结构分析

采用傅里叶红外光谱(FT-IR)分析了热聚合改性和添加无烟煤热聚合改性中温煤沥青的组分结构变化;采用综合热分析仪(TG-DTG)研究了热聚合改性和添加无烟煤热聚合改性中温煤沥青的热解缩聚特征;采用气相色谱质谱联用(GC-MS)等技术初步探讨了煤沥青热聚合改性机理.研究结果表明:无烟煤热聚合改性的中温煤沥青,芳香度明显提高;无烟煤促进了中温煤沥青热处理过程中缩聚反应的进行.     

SEM analysis of the changes of carbon layer structure of mesocarbon microbeads heat-treated at different temperatures

Mesocarbon microbeads (MCMB) with narrow size distribution, excellent sphericity and no obvious conglutination have been prepared with a coal tar pitch containing quinoline insolubles (QI) as the raw material. Optical microscopy and scanning electron microscopy (SEM) are used to examine the structure of the MCMB. It has been found that SEM technique shows the structural information of MCMB clearly in the form of micrographs even when the structure of MCMB is complex, while the optical technique is useful for analysis of the regular structure of the mesophase spheres but cannot be effectively used to analyze either the complex structure of the green MCMB or the structures of the further heat-treated ones at different temperatures. According to the characteristics of the carbon layers, the structures of the as-prepared MCMB in the present experiment could be classified as (I) Parallel Layer type structure and (2) Bent Layer type structure with the carbon layers gathering at one or two points in the MCMB. In the experiments, SEM is also utilized to investigate the structures of MCMB that are heat-treated at different temperatures. It has been found that the MCMB without any further heat-treatment show no layered-carbons, while the ones heat-treated at temperaturehigher than 1000℃ exhibit obvious layered carbons across their sections. When increasing the heat-treatment temperature, the carbon layers become thinner and flatter.     

煤燃烧过程中的热应力破碎的研究

从理论上分析了煤燃烧过程中热应力破碎的特性．结果表明煤颗粒的抗压强度越小、煤的热传导系数越小、颗粒越大、炉膛内的温度越高、烟气对颗粒的传热性能越好,煤颗粒越容易或越早破碎．对于小颗粒的情况,尽管颗粒内部的温度梯度很小,但是由于温度的瞬时巨大的变化,在极短的时间内颗粒内部还是产生很大的应力,使得颗粒可能发生破碎。     

鲕状赤铁矿生物质低温磁化焙烧

对生物质磁化鲕状赤铁矿石进行研究,包括磁化温度、磁化时间、生物质用量以及赤铁矿石粒度对磁化效果的影响.在磁化温度为600℃,赤铁矿石与生物质的质量比为10：2的情况下,利用生物质热解产生的气体和焦油在30 min内可以完全磁化粒度为0.074 mm (>72.5%)的赤铁矿石,验证了生物质替代煤基还原剂进行磁化焙烧具有一定的可行性.此外,矿石粒度对磁化焙烧还原度的影响比较大,矿石粒度越大,完全磁化所需时间越长.根据生物质还原剂的特点,适当地减小矿石粒度可以有效改善赤铁矿石的磁化性能.     

Pseudo-<Emphasis Type="Italic">in-situ</Emphasis> stir casting: a new method for production of aluminum matrix composites with bimodal-sized B<Subscript>4</Subscript>C reinforcement

A new method was applied to produce an Al-0.5wt%Ti-0.3wt%Zr/5vol%B₄C composite via stir casting with the aim of characterizing the microstructure of the resulting composite. For the production of the composite, large B₄C particles (larger than 75 μm) with no pre-heating were added to the stirred melt. Reflected-light microscopy, X-ray diffraction, scanning electron microscopy, field-emission scanning electron microscopy, laser particle size analysis, and image analysis using the Clemex software were performed on the cast samples for microstructural analysis and phase detection. The results revealed that as a consequence of thermal shock, B₄C particle breakage occurred in the melt. The mechanism proposed for this phenomenon is that the exerted thermal shock in combination with the low thermal shock resistance of B₄C and large size of the added B₄C particles were the three key parameters responsible for B₄C particle breakage. This breakage introduced small particles with sizes less than 10 μm and with no contamination on their surfaces into the melt. The mean particle distance measured via image analysis was approximately 60 μm. The coefficient of variation index, which was used as a measure of particle distribution homogeneity, showed some variations, indicating a relatively homogeneous distribution.     

高铁铝土矿热压块抗压强度影响因素响应曲面优化

基于响应曲面优化法,采用中心组合设计,系统研究了配煤量、矿粉粒度、煤粉粒度等工艺参数及其交互作用对高铁铝土矿热压块抗压强度的影响,并建立了相关的数学预测模型.研究表明,各工艺参数对高铁铝土矿热压块抗压强度的影响显著,其程度大小依次为配煤量、矿粉粒度、煤粉粒度;所建立的数学模型相关系数为0.958 9,该模型能够预测高铁铝土矿热压块抗压强度随各参数的变化规律;利用该模型对高铁铝土矿热压块的制备工艺进行了参数优化,优化制备工艺参数为:配煤量19.0%,矿粉粒度96μm,煤粉粒度80μm,在此条件下制备的热压块抗压强度为1 024.3 N,与模型预测值1 000 N接近,相差只有2.43%,说明该数学模型能够为高铁铝土矿热压块制备工艺的优化提供参考.     

Fabrication method and microstructural characteristics of coal-tar-pitchbased 2D carbon/carbon composites

The lignin-cellulosic texture of wood was used to produce two-dimensional(2D) carbon/carbon(C/C) composites using coal tar pitch. Ash content tests were conducted to select two samples among the different kinds of woods present in Iran, including walnut, white poplar, cherry, willow, buttonwood, apricots, berry, and blue wood. Walnut and white poplar with ash contents of 1.994wt% and 0.351wt%, respectively, were selected. The behavior of these woods during pyrolysis was investigated by differential thermal analysis(DTA) and thermo gravimetric(TG) analysis. The bulk density and open porosity were measured after carbonization and densification. The microstructural characteristics of samples were investigated by scanning electron microscopy(SEM), X-ray diffraction(XRD), and Fourier-transform infrared(FT-IR) spectroscopy. The results indicate that the density of both the walnut and white poplar is increased, and the open porosity is decreased with the increasing number of carbonization cycles. The XRD patterns of the wood charcoal change gradually with increasing pyrolysis temperature, possibly as a result of the ultra-structural changes in the charcoal or the presence of carbonized coal tar pitch in the composite's body.     

Synthesis of nanocrystalline NiCrC alloy feedstock powders for thermal spraying by cryogenic ball milling

Nanocrystalline NiCrC alloy powders with a qualified particle size distribution for thermal spraying were synthesized using the cryogenic ball milling (cryomilling) method. The morphology, microstructure, size distribution, and phase transformation of the powders were characterized by scanning electron microscopy (SEM), laser scattering for particle size analysis, X-ray diffraction (XRD), and transmission electron microscopy (TEM). After cryomilling for 20 h, the average grain size of the as-milled powders approached a constant value of 30 nm by XRD measurement. The average particle size slightly increased from 17.5 to 20.3 μm during the 20-h milling. About 90vol% of the powders satisfied the requirement for thermal spraying with the particle dimension of 10-50 μm, and most of the powders exhibited spherical morphology, which were expected to have good fluidity during thermal spraying. The Cr₂O₃ phase formed during the cryornilling process as revealed in the XRD spectra, which was expected to enhance the thermal stability of the as-milled powders during the followed thermal spraying or other heat treatment.     

热聚合改质过程中煤沥青聚合程度表征的研究

在20升热聚合反应釜中对中温煤沥青进行热聚合改质处理，研究了热解缩聚期间煤沥青软化点的变化规律，讨论了软化点在评价煤沥青聚合程度中的作用，并找出了热聚合改质过程中煤沥青软化点与结焦值和甲苯不溶物之间的关联性。     

煤焦油的分离技术及应用

本文简述了国内外煤焦油加工工艺的现状,指出了存在的问题,并系统总结了蒸馏、结晶、吸附、膜分离以及溶剂萃取等分离技术在煤焦油分离中的应用．提出了煤焦油的溶剂萃取新加工工艺,该工艺克服了传统加工工艺的缺点,有望推动我国煤焦油分离工业的发展．