用脱盐碱渣与活化粉煤灰试制砌块

通过试验 ,确定碱渣经磁处理脱盐后在粉煤灰中添加的可行性 ,利用磁处理技术除去工业碱渣中的可溶盐 ,能免除可溶盐对制品产生的破坏作用。     

高盐废水脱盐处理技术的研究现状

目前，针对高盐废水的处理要求越来越严格，如何使废水中的盐分、有机污染物等进行分离以及资源化回收利用，争取达到绿色排放，是我们目前需要解决的重要问题。阐述了传统的物理脱盐处理技术，从热法：多级闪蒸、多效蒸发、机械蒸汽再压缩蒸发（MVR）和膜分离法的研究现状入手，分析了各工艺的优缺点。结合新型电化学脱盐技术——电渗析和电吸附除盐技术的研究现状及应用情况，总结得出两种电化学脱盐技术与传统物理脱盐技术相比的优势所在，阐述了电吸附法良好的应用前景，并对未来高盐废水脱盐技术的发展方向进行了展望。     

高温煤焦油脱水脱盐工艺优化研究

针对煤焦油原料中盐含量较高造成的设备磨损和蒸馏塔腐蚀等问题,选用一种典型的高温煤焦油为原料,分别研究破乳剂、破乳剂添加量、水添加量、温度和静置时间对高温煤焦油脱水脱盐效果的影响,并优化工艺条件。结果表明,破乳剂和温度是最主要的2个影响因素,并得到优化的脱水脱盐条件:优选醇类聚醚破乳剂,破乳剂的添加量为100 mg/kg,水添加量为20%,在130℃温度下恒温4 h,经处理后的高温煤焦油盐含量小于5 mg/kg,水含量小于1.50%。     

炼油污水中盐来源解析及控制策略

炼油污水中的盐主要由原油、新鲜水以及投加的各类助剂、药剂带入。不同来源污水中,催化裂化烟气脱硫水盐浓度最高且盐量占比最大,除盐水站的两股浓排水盐量占比也较大,是重点管控对象。提出了分质脱盐的控制策略,其中除盐水站反渗透浓水单独脱盐,杂质浓度相对较低,预处理难度小,脱盐流程短;离子交换树脂统一采用硫酸再生后,树脂再生水与催化裂化烟气脱硫水两股高含盐污水硫酸钠含量高,直接脱盐生产硫酸钠和少量杂盐,不需要分盐单元。与常规的末端脱盐方案相比,按照此分质脱盐控制策略设计的方案处理流程更为简单,可节省投资并利于运行维护。     

专论炭和石墨表面密切的处理方法

在常压下使用含有高温可降合液态树脂的处理液，采用侵溃方法对多孔炭和石墨制品表面进行密切，当液态处理溶液进入制品表面时，因其具有足够低的粘度而渗透到制品表面的气孔中。然后经控制热循环处理、固化渗透树脂。紧接着使用表面清理技术，在制品表面上制成一种薄的、层状的、液体和气体不透性的涂层。     

纳滤膜在染料生产废水处理中的应用

采用超滤、纳滤集成技术,对高盐度、高色度、高COD的染料生产废水进行中试处理试验,分别考察了恒容脱盐、恒压浓缩、连续化处理等不同工艺的效果.结果表明,纳滤膜对COD的去除率大于90%,对色度去除率基本为100%,对染料截留率大于97%,能有效截留废水中的染料和有机物,同时一价盐(NaCl)大部分能透过膜.因此,对染料废水进行脱盐,浓缩、回用及连续化处理是可行的.     

煤热解焦油化学破乳脱盐试验研究

为减少煤焦油乳状液水中大量无机盐对分馏塔冷凝器等设备的腐蚀,促进煤焦油与水分离,利用化学破乳方法对煤焦油进行了脱盐试验,探讨了煤焦油化学破乳的可行性,考察了破乳剂类型、破乳剂添加量、注水量、脱盐温度及停留时间等试验条件对煤焦油脱盐效果的影响。结果表明,自制聚醚破乳剂脱盐效果较佳,破乳剂添加量100×10~(-6),注水量15%,脱盐温度110℃,脱后煤焦油中盐含量均出现明显拐点,停留时间在一定范围内对脱盐效果影响甚微。因此,自制聚醚破乳剂较其他2种较广泛应用于煤焦油脱水的破乳剂具有更好的脱盐效果,这主要归因于其特殊结构与煤焦油中沥青质有很强的相互作用。     

纳滤膜用于1,3-丙二醇发酵液脱盐工艺研究

1,3-丙二醇(PDO)发酵液中PDO浓度7％～10％,水含量82％～85％,此外还含有2％～3％ 的盐,主要为二价盐丁二酸纳和硫酸钠,此外还有少量乙酸钠,常规脱盐工艺是电渗析脱盐,离子交换膜存在膜易污染等难题,尝试采用纳滤膜对PDO发酵液进行脱盐工艺研究,筛选了不同规格的几种纳滤膜分别对PDO发酵液进行脱盐,研究结果...     

GOLDSTREAM饱和环保脱盐工艺

传统的脱盐水处理一般采取一、二级离子交换除盐和反渗透加混床水处理方式,这两种方法分别存在酸碱消耗量大、废水排放率高和水的利用率低、耗电多、制水成本高、且对预处理系统要求较高的缺点。针对以上现象,研制开发了GOLDSTREAM饱和离子交换脱盐设备,该设备利用GOLDSTREAM专用同晶粒抗渗透树脂,并针对树脂特点确立了GOLDSTREAM饱和环保脱盐水处理工艺,以解决原水电导≤2000μS／cm以下水质经济适用的水处理脱盐问题。     

3种酸改性活性炭纤维电吸附脱盐性能研究

为提高活性炭纤维(ACF)应用于电吸附装置的脱盐性能,分别采用H2SO4、HNO3及H3PO4为改性剂对ACF进行改性,得到ACF-1、ACF-2、ACF-3,对其进行了表面形貌和化学结构的表征;并应用于自制2级电吸附装置将改性前后的ACF应用于处理模拟NaCl盐水和炼化废水厂反渗透(RO)浓水。结果表明,在HNO3的刻蚀作用下,ACF表面形貌和孔结构发生了变化,将酸性含氧官能团引入了表面;3种酸改性前后4种ACF电极材料对于模拟NaCl盐水和炼化废水厂RO浓水脱盐都具有较好处理效果,其中采用ACF-2除盐效果最好,对模拟NaCl盐水及RO浓水的最大除盐率分别为36.76%和16.54%。表明3种酸改性增强了ACF的电吸附脱盐性能,酸改性ACF电极电吸附脱盐技术可用于处理高盐分RO浓水。     

Fabrication of SiC reticulated porous ceramics with multi-layered struts for porous media combustion

Silicon carbide reticulated porous ceramics (SiC RPCs) with multi-layered struts were fabricated at 1450 °C by polymer sponge replica technique, followed by vacuum infiltration. The effect of additives (polycarboxylate, ammonium lignosulfonate and sodium carboxymethyl-cellulose) on the rheological behavior of silicon carbide slurry was firstly investigated, and then the slurry was coated on polyurethane open-cell sponge template. Furthermore, alumina slurry was adopted to fill up the hollow struts in vacuum infiltration process after the coated sponge was pre-treated at 850 °C. The results showed that the coating thickness on the struts and the microstructure in SiC RPCs were closely associated with the solid content of alumina slurry during vacuum infiltration. The typical multi-layered strut of SiC RPCs could be achieved after the infiltration of an alumina slurry containing 77 wt% solid content. The compressive strength and thermal shock resistance of the infiltrated specimens were significantly improved in comparison with those of non-infiltrated ones. The improvement was attributed to the in-situ formation of reaction-bonded multilayer struts in SiC RPCs, which were characterized by the exterior coating of aluminosilicate-corundum, middle part of mullite bonded SiC and interior zone of corundum.     

预处理工艺对真空油炸脱水马铃薯脆片品质的影响

通过热烫、冷冻、渗透液处理等预处理技术对真空油炸马铃薯脆片品质影响作了比较;综合各指标分析,得出了马铃薯脆片真空油炸的较佳预处理工艺。实验结果表明,冷冻参数对油炸马铃薯脆片水分质量分数不存在主要影响,热烫温度是主要影响因素;渗透组的马铃薯脆片,随着渗透浓度的增加,其水分质量分数逐渐减少。冷冻参数对油炸马铃薯脆片脂肪质量分数影响也不大;热烫时间较短的马铃薯脆片油炸后脂肪质量分数较高,热烫时间较长的马铃薯脆片油炸后脂肪质量分数较低。热烫温度75℃、时间6min的脂肪质量分数最低;渗透浓度越高,马铃薯脆片油炸后脂肪质量分数越低。     

Spontaneous Infiltration of Iron Silicides into Silicon Carbide Powder Preforms

The infiltration of liquid Fe₃Si (mp of ∼1300°C), Fe₅Si₃ (mp of ∼1210°C), and FeSi (mp of ∼1410°C) into SiC powder preforms was performed at various infiltration temperatures for 60 min under either argon flow or dynamic vacuum. The amount of infiltration under various infiltration conditions was studied as a function of infiltration temperature. For the preforms as-pressed from raw SiC powder, the amount of infiltration of the three silicides under argon flow was independent of their melting points, but suddenly increased within a common temperature range from 1450° to 1550°C. Thermodynamic analyses indicated that the common temperature range corresponded to the temperature at which the SiO₂ on the surface of the SiC particles was decreased under argon flow. Infrared spectroscopy showed SiO₂ on the surfaces of as-received SiC powder particles, but not on the surfaces of the SiC powder particles fired under argon at 1600°C. The amount of infiltration of the as-pressed SiC under vacuum and of fired SiC under argon and vacuum exhibited an obvious dependence on the silicide melting points. This was attributed to the SiO₂ reduction taking place at temperatures lower than the melting points of the silicides. The amount of infiltration was then controlled by the melt viscosity.     

Vacuum infiltration of copper aluminate by liquid aluminium

This paper studies attained microstructures and reactive mechanisms involved in vacuum infiltration of copper aluminate preforms with liquid aluminium. At high temperatures, under vacuum, the inherent alumina film enveloping the metal is overcome, and aluminium is expected to reduce copper aluminate, rendering alumina and copper. Under this approach, copper aluminate toils as a controlled infiltration path for aluminium, resulting in reactive wetting and infiltration of the preforms.Ceramic preforms containing a mixture of Al₂O₃ and CuAl₂O₄ were infiltrated with aluminium under distinct vacuum levels and temperatures, and the resulting reaction and infiltration behaviour is discussed. Copper aluminates stability ranges depend on vacuum level and oxygen partial pressure, which determine both CuAl₂O₄ and CuAlO₂ ability for liquid aluminium infiltration. At 1100 °C and 0.76 atm vacuum level CuAl₂O₄ is stable, indicating pO₂ above 0.11 atm. Reactive infiltration is achieved via reaction between aluminium and CuAl₂O₄; however, fast formation of an alumina film blocking liquid aluminium wicking results in incipient infiltration. At 1000 °C and 3.8 × 10⁻⁷ atm vacuum level, CuAlO₂ decomposes to Cu and Al₂O₃ indicating a pO₂ below 6.0 × 10⁻⁷ atm; infiltration of the ceramic is hindered by the non-wetting behaviour of the resulting metal alloy. At 1000 °C and 1.9 × 10⁻⁶ atm vacuum level CuAlO₂ is stable, indicating pO₂ above 6.0 × 10⁻⁷ atm. Extensive infiltration is achieved via redox reaction between aluminium and CuAlO₂, rendering a microstructure characterised by uniform distribution of alumina particles amid an aluminium matrix.This work evidences that liquid aluminium infiltration upon copper aluminate-rich preforms is a feasible route to produce Al-matrix alumina-reinforced composites. The associated reduction reaction renders alumina, as fine particulate composite reinforcements, and copper, which dissolves in liquid aluminium contributing as a matrix strengthener.     

Effects of polycarbosilane infiltration processes on the microstructure and mechanical properties of 3D-Cf/SiC composites

Three-dimensional braided carbon fiber-reinforced silicon carbide (3D-C_f/SiC) composites were prepared through eight cycles of infiltration of polycarbosilane (PCS)/divinylbenzene (DVB) and subsequent pyrolysis under an inert atmosphere. The effects of infiltration processes on the microstructure and mechanical properties of the C_f/SiC composites were investigated. The results showed that increasing temperature could reduce the viscosity of the PCS/DVB solution, which was propitious to the infiltration processes. The density and flexural strength of 3D-C_f/SiC composites fabricated with vacuum infiltration were 1.794 g cm⁻³ and 557 MPa, respectively. Compared to vacuum infiltration, heating and pressure infiltration could improve the infiltration efficiency so that the composites exhibited higher density and flexural strength, i.e., 1.944 g cm⁻³ and 662 MPa. When tested at 1650 °C and 1800 °C in vacuum, the flexural strength reached 647 MPa and 602 MPa, respectively.     

Quantitative determination of ZrC in new ceramic materials by Fourier transform infrared spectroscopy

Zirconium carbide-based biomorphic ceramics have been manufactured by vacuum infiltration of zirconium-oxychloride (ZrOCl₂·8H₂O) sol into natural wood. After vacuum-assisted infiltration, the specimens were dried in air and pyrolysed at 800 °C in Ar-atmosphere. The infiltration and drying process were repeated up to four times. Finally, the specimens were hold at 1550 °C in a vacuum furnace to form ZrC. The results of the process of synthesis have been studied using scanning electron microscopy (SEM). For evaluating the yield of the synthesis, a new method by Fourier transform infrared spectrometry (FTIR) has been developed for the direct determination of ZrC by absorbance measurements in KBr pellets. The procedure was based on the use of the ratio between the absorbance of the characteristic band of zirconium carbide and those of an oxalate internal standard added to samples. A multivariate calibration strategy based on inverse least squares and the standard addition approach was employed for quantification. The results obtained for all ZrC-ceramics studied were satisfactorily compared with those obtained by X-ray diffractometry (XRD). The proposed method was also applied to the analysis of synthetic samples prepared by mixing pyrolyzed wood with ZrC, the results indicated good recovery in all instances.     

Liquid metal infiltration of silicon based alloys into porous carbonaceous materials. Part II: Experimental verification of modelling approaches by infiltration of Si-Zr alloy into idealized microchannels

In this work, the mechanisms leading to the pore closure in reactive melt infiltration (RMI) of carbon by pure silicon and a near eutectic Si-8 at-pct Zr alloy at 1500 and 1700 °C under vacuum were studied. Various geometrical configurations of microchannels were fabricated via laser ablation of glassy carbon plates. The micron size capillary channels allowed simplifying the complicated porosity distribution in the infiltration of powder or fibres based porous preform while keeping the physical dimensions in the range of where the physical phenomenon of pore closure takes place. The extent of infiltration was analysed by means of X-ray radiography. For RMI of pure Si, the widely accepted decrease in capillary radius by the formation of a solid state SiC layer by the reaction of liquid Si and C was observed, but did not lead to closure and it is hence not the infiltration limiting step in channels as small as 10 μm. However, in the case of the Si-Zr alloy infiltration, another mechanism of pore closure was observed, namely the precipitation of zirconium silicides at the infiltration front, due to Zr enrichment in the alloy by the continuous consumption of Si for the formation of SiC.     

Reaction forming of silicon carbide ceramic using phenolic resin derived porous carbon preform

SiC ceramics were prepared with porous carbon preforms derived from phenolic resin by a reaction-forming method. The effects of the structure of the preform pores and the infiltration process on the properties of SiC ceramics were investigated, and components with complex shapes were fabricated by combining this process with stereolithography (SLA). Dense SiC ceramics were obtained from carbon preforms with high apparent porosities, but SiC ceramics with many macrodefects resulted from a carbon preform with an apparent porosity of 39%. The infiltration of molten silicon into the preform pore channel was accelerated under vacuum pressure, resulting in an increase in the depth of the Si infiltration. The growth of SiC was predominantly controlled by carbon diffusion at the last stage of the reaction. The extended grain growth caused the SiC grains to coalesce and some free Si was enveloped in the SiC grains. SiC components with complex geometries were fabricated by combining reaction forming with SLA. The geometry was controlled by SLA.     

Significance of modification of slurry infiltration process for the precursor impregnation and pyrolysis process of SiCf/SiC composites

Several intermediate steps were applied before the precursor infiltration and pyrolysis process to improve the infiltration of SiC slurry for promoting the infiltration of SiC slurry into fiber voids. These steps include sonication, popping, electrophoretic deposition, vacuum infiltration and cold isostatic pressing (CIP). The intermediate processes, especially popping and CIP, had a beneficial effect on green density enhancement and improving the homogeneous infiltration of the slurry into fiber fabrics. The density of the SiC_fiber/SiC_filler green body was 2.20 g/cm³, which corresponded to 68 % of relative density. The SiC_f/SiC composite has a high density of 2.65 g/cm³ after seven PIP cycles.     

Improved interlaminar shear properties of multiscale carbon fiber composites with bucky paper interleaves made from carbon nanofibers

The effects of bucky paper interleaves made from carbon nanofibers on interlaminar shear properties of carbon fiber reinforced composites (CFRPs) are studied. The study includes fabrication of bucky papers, resin impregnation by different techniques, i.e., soaking, hot-compression and vacuum filtration, followed by β-stage curing and the integration with carbon fiber prepregs to produce CFRP composites with bucky paper interleaves. The vacuum infiltration technique results in the best quality of polymer impregnation through bucky papers. Remarkable 31% and 104% improvements in interlaminar shear strength and mode-II shear interlaminar fracture toughness of the multiscale composites, respectively, are achieved with the incorporation of interleaves at failure-prone locations. The pertinent mechanisms responsible for the ameliorating effects of interleaves include improved interfacial adhesion and matrix shear strength for the interlaminar strengthening and crack-tip bridging and meandering for the toughening. The present technique can be used to incorporate carbon nanotubes (CNTs) or carbon nanofibers (CNFs) of high contents to strengthen/toughen at selective locations in FRP composites, which has not been possible previously because of the high viscosity caused by randomly-oriented CNTs/CNFs in a polymer resin.