超高功率石墨电极用针状焦评价方法探析

针状焦是制造高功率和超高功率电极的优质材料,用针状焦制成的石墨电极具有耐热冲击性能强、机械强度高、氧化性能好、电极消耗低及允许电流密度大等优点,针状焦根据使用的原料可分为石油系和煤系两类。以石油重油为原料生产的针状焦为油系,以煤焦油沥青及其馏分为原料生产的针状焦为煤系。两种针状焦生产工艺不完全相同,但用途基本相同。石油系以美国为代表,煤系则以日本为代表。     

超高功率石墨电极用针状焦评价方法探析北大核心

针状焦是制造高功率和超高功率电极的优质材料。用针状焦制成的石墨电极具有耐热冲击性能强、机械强度高、氧化性能好、电极消耗低及允许电流密度大等优点。针状焦根据使用的原料可分为石油系和煤系两类。以石油重油为原料生产的针状焦为油系,以煤焦油沥青及其馏分为原料生产的针状焦为煤系。两种针状焦生产工艺不完全相同,但用途基本相同。石油系以美国为代表,煤系则以日本为代表。     

添加剂对针状焦成焦结构的影响

针状焦具有热膨胀系数小、导电导热性能良好等特性,是生产超高功率石墨电极、特种炭素材料等高端炭素制品的原料。根据生产原料的不同,针状焦可分为油系针状焦和煤系针状焦。以石油渣油、催化裂化油浆等为原料生产的针状焦为油系针状焦;以煤焦油沥青及其馏分为原料生产的针状焦为煤系针状焦。近年来,对各种原料进行改性来生产针状焦的方法越来越受到人们的关注。本文综述了不同添加剂和原料对成焦结构的影响,并根据其作用机理进行了论述。     

煤系针状焦生产工艺浅谈

针状焦是制造高级石墨电极的主要原料. 其按原料不同分为油系和煤系两种.以石油重油为原料生产的针状焦为油系,以煤焦油沥青及其馏分为原料生产的针状焦为煤系.两种针状焦生产工艺不完全相同,但用途基本相同.     

国产宏特针状焦生产Φ350mm超高功率石墨电极

以国产针状宏特焦为原料采用传统生产流程及国际标准流程生产Φ350mm超高功率石墨电极,并对其生产过程中的工艺进行控制。结果表明,用国产宏特针状焦为原料采用国际标准流程生产Φ350mm超高功率石墨电极,理化指标完全达到用新日铁针状焦为原料生产Φ350mm超高功率石墨电极等同类产品,通过钢厂试用,其抗热震性能、抗氧化性能、消耗性能较好,能完全满足用户的使用要求;同时实现超高功率石墨电极国际标准流程,进一步降低生产成本。     

特级锦州石油系针状焦试制Φ300mmUHP石墨电极

阐述了用特级锦州石油系针状焦试制Φ300mmUHP石墨电极的全过程,并对压型、焙烧、浸渍和石墨化等工序的抽样编号电极进行直径、长度、质量和体积密度等数据跟踪。结果表明,特级锦州石油系针状焦可以用来生产Φ300mmUHP石墨电极。     

用锦西焦加CGG针焦生产Ф450mm高功率石墨电极

分析了锦西焦与CGG油系针状焦的特性；以锦西焦为主加CGG油系针状焦为原料，生产Ф450mm高功率石墨电极，并对其生产过程中的工艺进行控制。结果表明：用锦西焦为主加CGG油系针状焦生产Ф450mm高功率石墨电极是完全可行的。     

针状焦集约化技术的开发

针状焦是超高功率石墨电极、超级电容器、锂离子电极等的主要原材料,其集约化技术泛指依靠科技进步,提高工艺设备的性能,以最低的物耗、能耗取得最大的经济效益.煤系针状焦的集约化技术以原料精制后获得针状焦、碳纤维、溶剂油、耐火材料黏结剂为主要产品线;石油系针状焦的集约化技术以针状焦、汽柴油、超级活性炭为主要产品线.     

烩系针状焦生产工艺浅谈

针状焦是制造高级石墨电极的主要原料。其按原料不同分为油系和煤系两种。以石油重油为原料生产的针状焦为油系 ,以煤焦油沥青及其馏分为原料生产的针状焦为煤系。两种针状焦生产工艺不完全相同 ,但用途基本相同。美国在５０年代后期首先掌握了石油系针状焦的生产技术。由于石油加工趋向催化裂化等轻质化深加工方向发展 ,致使油系针状焦原料减少。加之７０年代两次石油危机 ,更使人们感到原料供应的不稳定。于是 ,７０年代以来 ,日本、德国等国家均致力于开发煤系针状焦技术。１９７９年 ,日本煤系针状焦实现工业化生产,使油系和煤系针状焦…     

电炉钢产能扩大，大规格超高功率石墨电极用量增加针状焦大规模国产化迫在眉睫

针状焦是生产大规格超高功率石墨电极的主要原料，石墨电极的最终性能在很大程度上取决于原料针状焦的性能。由于大规格超高功率石墨电极必须有良好的物理机械性能（电阻率低、体积密度大、机械强度高、热膨胀系数小、抗热震性能好），普通石油焦无法满足要求，只有以针状焦为原料生产的石墨电极，才能达到超高功率电炉冶炼工艺的要求。     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

典型煤碳燃烧特性研究和数值模拟

本文以三种典型煤的碳燃烧为研究对象，分别采用简单一维沉降燃烧方式和等温加热燃烧方式，实验研究了煤在快速加热条件下，其碳的初期和中，后期燃烧过程。以实验为基础，建立了煤的碳燃烧模型，变工况数值模拟了煤的碳燃烧过程，揭示了煤不同条件下的单颗粒碳燃烧特性。     

用两个形状指数表征粉煤灰颗粒形貌的研究

引用两个形状指数表征颗粒形状的概念,即先将颗粒形状近似为椭圆,再将椭圆图像分离:以圆为基准的颗粒宏观形状指数δ;以光滑椭圆为基准的颗粒轮廓凹凸度,即微观形状指数ζ。分析和发展了近似椭圆模型。并运用图像分析仪对粉煤灰、水泥样品进行实验。结果表明,粉煤灰颗粒的两个形状指数δ和ζ都大于水泥颗粒。证明粉煤灰颗粒的球形度、表面光滑度优于水泥,而且,随着粒径增大,δ和ζ呈下降趋势,表明磨制颗粒越粗。(?)粒形状越不规则。文中还运用近似椭圆模型再现了颗粒的模拟图像。     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.