莫来石复合陶瓷微滤膜的制备与表征

采用天然矿物莫来石和高岭土为主要原料制备莫来石基复合陶瓷微滤膜,对制备的莫来石支撑体和复合微滤膜进行了结构与性能表征.结果表明,采用莫来石微粉(d50=9.85μm)为主要原料,并加入10%高岭土,可通过干压成型制备多孔莫来石陶瓷膜支撑体.经1250℃保温3h烧成后,支撑体平均孔径和孔隙率分别为2.1μm和46.9%,水通量为9.1m3·m-2·h-1·bar-1,抗弯强度为23.1MPa.通过浸渍涂覆法和固态粒子烧结法在莫来石支撑体上制备了莫来石微滤膜层,优化的浆料制备条件为:固含量10%、pH=11、7%PVA作粘结剂和0.8%PAA作分散剂.制备的莫来石微滤膜层经1200℃保温2h烧成后,平均孔径和厚度分别为0.24μm和18μm,复合微滤膜稳定水通量可达0.83m3·m-2·h-1·bar-1,表现出好的渗透性能,可应用于微滤分离过程.     

多孔氧化铝支撑体的制备与表征

以α-Al2O3粉末为骨料,采用塑性挤压成型技术和固态粒子烧结法制备Al2O3多孔陶瓷支撑体。研究了粘结剂和成孔剂的种类对支撑体性能的影响。研究结果表明:通过选用合适的粘结剂和成孔剂,可制得孔径分布窄、孔隙率高的支撑体。     

活性污泥对管式多孔α-Al_2O_3陶瓷膜支撑体性能影响的初步研究

以剩余活性污泥作为支撑体的成孔剂,采用滚压成型及熔膜芯法制备管状多孔α-Al2O3陶瓷膜支撑体,研究了粘结剂羧甲基纤维素(CMC)和活性污泥的加入量对氧化铝陶瓷膜支撑体品质的影响。结果表明,随着成孔剂和粘结剂的增多,支撑体孔隙率和渗透通量呈增大趋势,孔隙率最大可达43.07%,纯水通量在0.4~1.0 MPa压力下变化范围为12 786.67~37 617.84 L/(m2·h·MPa)。     

活性污泥对管式多孔α-Al_2O_3陶瓷膜支撑体性能影响的初步研究

以剩余活性污泥作为支撑体的成孔剂,采用滚压成型及熔膜芯法制备管状多孔α-Al2O3陶瓷膜支撑体,研究了粘结剂羧甲基纤维素（CMC）和活性污泥的加入量对氧化铝陶瓷膜支撑体品质的影响。结果表明,随着成孔剂和粘结剂的增多,支撑体孔隙率和渗透通量呈增大趋势,孔隙率最大可达43.07%,纯水通量在0.4~1.0 MPa压力下变化范围为12 786.67~37 617.84 L/（m2·h·MPa）。     

烧成温度对MgO-TiO2复合无机陶瓷微滤膜支撑体性能的影响

采用添加造孔剂高温烧结法制备了氧化镁-二氧化钛（MgO-TiO₂）复合无机陶瓷微滤膜支撑体。分别研究了相同烧结制度下不同最高烧结温度、相同最高烧结温度不同的烧结制度下样品的孔隙率、抗弯强度及纯水通量的变化情况。采用热重分析（TG-DSC）、电子扫描电镜（SEM）和万能试验机等对样品进行热分析、观察样品形貌及抗弯强度等性能测试。研究表明,最高烧结温度和烧结制度对样品的性能有很大影响,采用最高烧结温度为1 400 ℃、升温速率分别为4、8、2 ℃/min的1400-482烧结制度所制备的支撑体的性能最佳,孔隙率为37.57%,抗弯强度为108.65 MPa,纯水通量为4 040 L/（m²?h?MPa）。     

聚乙烯醇对氧化铝支撑体性能的影响

以α-Al2O3粉末为骨料，以聚乙烯醇（PVA）作粘接剂和成孔剂，采用塑性挤压成型技术和固态粒子烧结法制备氧化铝多孔陶瓷支撑体。研究了有机物作粘接剂的同时也作成孔剂使用时对多孔氧化铝支撑体性能的影响。研究结果表明：以有机物PVA作开孔剂以及泥料的预处理工艺可以极大地提高氧化铝支撑体的纯水通量；有机物PVA作开孔剂时其加入种类、方式和加入量对氧化铝支撑体的平均孔径及孔径分布、孔隙率、抗弯强度等性能都有影响。通过选用合适的成孔剂种类、加入方式以及加入量，可制得平均孔径1．9μLm、孔隙率45．6％、抗弯强度22．31MPa的高通量氧化铝支撑体。     

泥料含水量对粉煤灰陶瓷膜支撑体性能的影响

泥料含水量是陶瓷生产中的重要参数,会影响陶瓷的收缩率、抗弯强度等性能。以电厂粉煤灰为主要原材料、糊精为造孔剂、羧甲基纤维素为黏结剂,采用挤出成型法制备了管状多孔陶瓷膜支撑体。通过控制陶瓷泥料用水量和烧结保温时间制备了不同支撑体,并对支撑体进行性能表征,考察了泥料含水量和烧结保温时间对支撑体微观结构、收缩率、孔隙率、孔径以及机械强度等性能的影响。结果表明：在水/固质量比质量为0.19时,1 150℃保温烧结2 h获得孔隙率40.5%、抗弯强度23.6 MPa、平均孔径0.41μm的支撑体。制备的支撑体应用于脱硫废水微滤处理,固体悬浮物截留率99.98%。为制备低成本粉煤灰陶瓷膜支撑体提供研究基础,有利于膜法水处理的扩大化应用。     

高温气固分离SiC多孔陶瓷材料制备及性能研究

本文利用等静压成型高温气固分离碳化硅多孔陶瓷支撑体,研究了碳化硅含量、造孔剂含量、成型压力及烧成温度对碳化硅多孔陶瓷支撑体孔隙率及抗折强度的影响。通过研究发现,碳化硅含量在88wt%、成型压力为40 MPa、烧成温度为1330℃时,制备的碳化硅支撑体性能较为理想,可用于工业化生产。     

α-Al_2O_3管式微滤膜的制备工艺研究

以α-A12O3微粉(平均粒径为1.5μm)、苏州土为主要原料,采用浸浆法在管状A12O3陶瓷支撑体上制备微滤膜层。探讨了分散剂的加入量对浆料稳定性的影响,考察了浆料的固含量、浸浆时间、烧成制度等与微滤膜层性能的关系。结果表明,最佳的浆料配方为α-Al2O3(1.5μm):96wt%,苏州土:4wt%,PAAS:0.25wt%,HPMC4:wt%。最佳制膜工艺条件:浆料固含量为13wt%,浸渍时间为60s,膜的烧成温度1250℃,保温2h。SEM测试显示,制备的微滤膜层厚度20￣25μm,均匀、无缺陷。     

烧结制度及造孔剂用量对粉煤灰基多孔陶瓷膜支撑体性能的影响

以粉煤灰为原料,采用挤压成型和固态粒子烧结法制备管状粉煤灰基多孔陶瓷膜支撑体.采用TG-DSC技术对粉煤灰进行了热分析,采用SEM和XRD技术对样品的微观结构及物相组成进行了分析,并测定了样品的开孔率、抗压强度及空气渗透速率等性能指标.研究了烧结温度、保温时间和造孔剂添加量对支撑体性能的影响.结果表明:支撑体晶相组成主要为赤铁矿、红柱石和石英;烧结温度为1000 ℃,保温2 h,仅添加1%的粘结剂,不添加造孔剂的条件下制备出的管状支撑体综合性能最优,此时的支撑体孔隙率为44.95%,抗压强度为8.92 MPa,空气渗透速率为2.57×104 m3·h-1·m-2·MPa-1.     

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.     

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…     

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.     

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。     

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。     

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.     

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。     

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。