焦炭结构对炭—石墨制品性质的影响

石墨制品的性质受骨料焦炭的许多参数(即焦炭结构和焦炭质量)的影响。然而,由于石墨化处理过程中所产生的相互影响,焦炭的任何单项指标都决定不了石墨制品的性质。因此,以下讨论焦炭性质及其相互制约对石墨制品的影响:包括宏观(长宽比)与微观结构;密度、孔度尺寸和形状与颗粒尺寸的关系;真密度;颗粒强度;焦炭颗粒膨胀和“晶账”特性(硫分)。另外,还讨论有关不同类型的焦炭产生的影响,以及原料形成生焦的转化过程,和对煅后焦的影响。     

炼焦煤粒度对焦炭耐磨强度的影响分析

本文通过分析不同入炉煤粒度组成炼制的焦炭耐磨强度,探寻了炼焦煤粒度与焦炭耐磨强度间的关系。日常生产中,应避免颗粒过大的炼焦煤进入焦炉,但也不必对炼焦煤过细粉碎。     

工艺因素影响焦炭颗粒耐压强度的试验研究

焦炭颗粒的耐压强度一直是焦炭颗粒最重要的性质之一。利用最近提出的表征焦炭颗粒耐压强度的新方法，就模压压力、加压方式、粒度组成范围、粒度大小、粒度配比等因素对单粒度或多粒度组成焦炭颗粒耐压 强度的影响进行了较为详细的试验研究。结果表明：（1）焦炭颗粒的粒度大小和粒度范围均可用其原始平均细度来表征。焦炭颗粒的原始平均细度越大，其耐压强度系数也就越高；（2）多粒度组成焦炭颗粒混合料的耐压能力比单粒度组成混合料的耐压能力要高得多。对多粒度组成焦炭颗粒而言，模压压力及粒度组成配比对其耐压强度系数的影响不甚明显；（3）分阶段缓慢加压到位比一次快速加压到位有利于提高焦炭颗粒的耐压强度系数。     

焦炭颗粒强度系数的测定

测定了不同粒度的焦炭在不同试验压力下的颗粒强度系数，研究了焦炭颗粒强度系数同试验力及试样粒度的关系，并提出了焦炭颗粒强度系数测定的适宜条件，在生产实践中，测定焦炭颗粒强度系数的试样粒度可选择４．０￣２．０ｍｍ，或根据情况选择８．０￣４．０ｍｍ；试验压力可选择４０ＭＰａ。     

提高石墨抗热震性能的途径

抗热震性是衡量石墨制品热性能的主要指标。本文叙述了原料选择、原料处理方法、焦炭骨料的颗粒分布、气相加压焙烧、糊料塑性化处理等理化性能与最终石墨制品热性能的关系,提出一些改善石墨抗热震性能的途径。     

粉煤灰理化性质及微观颗粒形貌研究

采用XRD、SEM和LS230激光粒度分析仪对粉煤灰进行了一系列的研究，包括粉煤灰的矿物组成；粉煤灰的粒度分布；粉煤灰中微观颗粒形貌。粉煤灰中的微观颗粒按所含主要元素可分为未燃尽炭粒、磁珠、钙珠及硅铝玻璃微珠。     

惰性粒度对焦炭强度的影响

高强度焦炭的生产技术有很多,其中有煤粉碎粒度控制技术.一般来说,炼焦煤粉碎得越细,焦炭强度越大.但是如果过度粉碎,煤的装入密度降低,会导致装煤量和焦炭强度降低.要防止过度粉碎并提高焦炭强度,准确把握惰性煤颗粒尺寸和焦炭强度的关系十分重要.本文将惰性煤的粒度调整为0.1～0.3mm、0.3～0.6mm、0.6～1.2mm、2.0～4.0mm、5.0～7.0mm以及10～15mm,并且按照一定的比例进行配料生产焦炭.通过焦炭显微镜分析,实际测量了惰性煤的尺寸,研究了惰性煤尺寸对焦炭强度(转鼓强度指数DI6和DI6-15)的影响.     

粉煤灰中的残余碳

粉煤灰中的残余碳是燃煤锅炉中煤未完全燃烧所产生的固体废弃物。残余碳的形成主要与燃料煤的组成和性质、锅炉特点、燃烧温度、空气量（燃烧时的氧气供给量）及燃烧时间（Ｏ工在锅炉内的停留时间）等因素有关。残余碳通常以单体半焦或焦炭、粘结在粉煤灰颗粒表面或包裹在粉煤灰颗粒中等几种形式存在，残余碳的粒度分布、比表面积、Ｈ和Ｏ的含量都有其特殊性。粉煤灰中的残余碳，不仅能反映锅炉的运行情况、影响锅炉烟气中ＣＯＸ的含     

微波改性高炉瓦斯泥颗粒的分形特性

对马钢高炉瓦斯泥颗粒进行了粒度分布和微观形貌的测定和表征,并结合数学模型研究了其微波改性前后的分形特性.结果表明,微波改性后瓦斯泥颗粒形貌出现粗糙度增大、孔隙结构变化明显、比表面积增大、形状更不规则化的特征.结合分形模型得到瓦斯泥中3种主要颗粒(含铁为主的烧结矿颗粒、焦炭颗粒和其他次要组分颗粒)的分形维数分别由改性前的...     

氧化物添加剂在碳—石墨制品中的结构转变及其作用

本文综述了氧化物添加剂在碳—石墨制品的热处理过程中所发生的结构转变和热力学性质，并分析讨论了它对碳—石墨制品的性能影响及其作用。     

添加炭素物料改善焦炭性能的研究

通过向炼焦配煤中添加石油焦、人造石墨和天然石墨并炼焦处理，研究了添加炭素物料对焦炭性能的影响，结果发现，添加少量炭素物料有效地提高了焦炭强度并降低了焦炭的反应性。     

Carbonization of petroleum binders. 1. Characteristics of solid products

Solid products of carbonization of residues (i.e. cokes) of vacuum distillation of crude oil, asphalt, and pitch have been studied. The objective was to determine the changes of composition and structure of cokes in relation to temperature. Investigations of elemental composition, functional group content, microscopic analysis, and X-ray diffraction of the products showed that with increasing temperature of carbonization, the degree of structure ordering, the dimensions of the pores, and the intensity of optical anisotropy of the cokes increases, as do the carbon, sulphur, and nitrogen contents; however, volatile matter, hydrogen, and functional-group contents in the cokes decrease.     

不同粒级骨料制备冶炼石英坩埚用高纯石墨材料的研究

分别选取1～0 mm粗结构、0.5～0 mm中粗结构和0.15～0 mm细结构3种粒级煅烧石油焦作为骨料,以中温煤沥青作为黏结剂和浸渍剂,制备出冶炼石英坩埚用高纯石墨材料.研究了不同粒级骨料对高纯石墨材料性能和显微结构的影响.研究表明:0.15～0 mm细结构样品的机械性能最好,1～0 mm粗结构的最差.X射线衍射(XRD)和扫描电镜(SEM)分析结果显示,1～0mm粗结构样品的石墨化程度不如0.5～0 mm中粗结构和0.15～0 mm细结构样品.综合热分析(TG-DSC)结果表明,1～0 mm粗结构样品的热失重温度区间主要集中在680～880℃,其抗氧化能力相对较差.     

Effect of palladium on the microstructure and grain boundary complexions in SiC

One of the main challenges in the study of TRISO (Tristructural Isotropic) coated fuel particles is the understanding of the diffusion of fission products through SiC. Among the elements produced inside the uranium kernel, it has been suggested that Pd might enhance the diffusion of other fission products. In this work, we have studied the interaction between Pd and SiC. We have observed that as Pd diffuses it can change the chemical composition and microstructure of SiC. Electron Backscattered Diffraction (EBSD) analysis showed that Pd increased the amount of high angle grain boundaries from 47% to 59%. Furthermore, we have observed that as Pd diffused, it changed the composition of SiC by leaving a trail of excess carbon at the grain boundary. This change in localized chemical composition and microstructure suggests a grain boundary complexion transition induced by Pd and a new way in which Pd can lead to faster diffusion routes for other fission products.     

低碳MgO-C材料的抗热震性研究

以电熔大结晶镁砂、天然鳞片石墨、纳米炭黑、酚醛树脂、铝粉等为主要原料制备w(C)=3%的低碳MgO-C材料,以其抗热震性为考核指标,选取颗粒级配、复合抗氧化剂、石墨粒度和复合结合剂4个因素,进行了四因素三水平正交试验。结果表明:在本试验范围内,颗粒级配是影响低碳MgO-C材料抗热震性的主要因素,复合抗氧化剂次之,石墨粒度和复合结合剂的影响基本相当;通过极差分析确定,镁砂颗粒级配(3～1、1～0.088和≤0.088mm的镁砂的质量比)采用50:23:27,复合抗氧化剂采用Al2.5+Mg-Al0.5+B4C0.5,石墨粒度采用10μm的,复合结合剂采用炭黑N220+沥青+酚醛树脂,可制备出抗热震性最佳的低碳MgO-C材料。     

Production of Periclase-Carbon Refractories at Semiluki Refractory Plant

The technology and commercial production of periclase-carbon articles with a regular grain composition from a raw material with unstable grain size are described. A comparative study of casting, elemental, and crucible graphite as the basic carbon component has shown that the best commercial properties are provided by the use of crucible graphite. Tests of periclase-carbon refractories without metallic aluminum and with various contents of aluminum have shown the possibility of a differentiated approach to the use of the antioxidant with allowance for the specific service conditions of the lining.     

Effects of the degree of graphitization and the presence of Fe, Ni, Al, and Si on the reaction stability of carbon materials to the action of CO2

With the use of industrial cokes, synthetic graphite, and graphite foams as an example, it was shown that the reactivity and, correspondingly, the thermal stability of carbon in a reaction with CO₂ can be regulated by increasing the fraction of graphite structures in the composition of a carbon material and by introducing the catalytic additives of 3d metals (iron and nickel) and also silicon or aluminum. The effect of the additives is explained by both a change in the degree of graphitization of the carbon material and the catalytic action on the course of reaction.     

煤基富勒烯(C_(60))的制备与提纯

<正>富勒烯是除石墨和金刚石外碳的第三种同素异构体,其代表性分子是C_（60）和C_（70）。大量研究成果表明,富勒烯的特殊球形空心分子结构赋予了它许多奇异的物理化学性质,在超导、非线性光学、催化剂等诸多领域显示出十分诱人的应用前景。目前,国内外主要以高纯石墨电极为原料制备富勒烯,由于煤的价格低廉且来源广泛,以煤炭为原料制备富勒烯的研究备受国外学者的关注。本文以冶金焦为原料用电弧法制备富勒烯,研究了实验操作条件及冶金焦性质与富勒烯收率间的关系。粗富勒烯以活性炭为固定相,甲苯为流动相的柱色谱分离提纯,考察了活性炭的孔隙结构及柱色谱的长度对C_（60）纯度和收率的影响。     

Mechanisms of TiB2 and graphite nucleation during TiC–B4C high temperature interaction

Reactive hot pressing of TiC–B₄C precursors was undertaken at 1800 °C to produce TiB₂ with carbon inclusions. Atomic mechanisms of titanium diboride nucleation, as well as sponge-like carbon inclusions and submicron platelets of graphite precipitation have been investigated. Precursor grain size, green body composition and synthesis time were varied to analyze phase transformation. The carbon left after B₄C high temperature decomposition is shown remaining as graphite sponge-like inclusions. Ab-initio calculations confirm that the boron atoms accumulation on (111) TiC plains leads to tensile stress. The developed stress cleaves TiC grains and enhances further reaction. Most of carbon expelled from TiC during its transformation into TiB₂ forms graphite submicron platelets.     

Influence of chemical composition on mechanical properties of spark plasma sintered boron carbide monoliths

Fully dense boron carbide monoliths exhibiting fine microstructure (i.e., submicrometric grain size) are sintered by Spark Plasma Sintering. Two different commercial powder batches, exhibiting different stoichiometries (i.e., B/C ratio and oxygen content) and various amounts of secondary phases (i.e., boric acid and free carbon), are used. Their chemical composition is well‐defined by coupling different methods (Transmission Electron Microscopy associated with XRD analyses, and Instrumental Gas Analysis), and are correlated with their mechanical properties, characterized from meso‐ to macro‐scopic scales by nano‐indentation and ultrasonic pulse echography. The presence of secondary phases (graphite and boric acid) is evidenced in various proportions in each powder batch. If the boric acid disappears during sintering, the graphite remains. However, for the considered amounts of graphite (lower than 1 wt%), the low variations in graphite content have no significant effect on hardness and elasticity values. At the opposite, the presence of oxygen in boron carbide lattice, leading to a boron oxycarbide phase, induces a decrease in both hardness and elasticity properties.