含钨工业废料中提取与分离三氧化钨的研究

分析了我国钨资源的现状,提出应合理利用钨二次资源,即含钨工业废料.探讨了目前含钨工业废料的主要来源,包括冶钨过程中的废渣、废硬质合金和含钨废催化剂.简介了国内外含钨工业废料中钨的提取方法,并开展了含钨废催化剂中提取与分离三氧化钨(WO3)的研究.实验结果表明,废催化剂的主要化学成分,除了氧外,其他元素主要有钨、钛、以及...     

高纯六氟化钨去除氟化氢的工艺研究

对高纯六氟化钨制备过程中,采用综合措施抑制电解制氟时氟化氢的挥发、球状氟化钠吸收氟化氢、液氮冷冻固化氟化氢而提纯氟气、六氟化钨低温冷冻抽真空除去氟化氢等物理过程,以及利用六氯化钨与氟化氢发生反应而去除氟化氢的化学过程。结果表明,电解产生的氟气中质量分数4.5%的HF,经过多步聚去除氟化氢后,精馏产品六氟化钨达到HF的质量分数小于5×10-6的高纯要求。解决了氟化氢与六氟化钨2者难以分离的技术问题。     

钨/环氧树脂辐射防护复合材料制备以及原位拉伸性能和微观组织演变

将硅烷偶联剂改性的钨粉加入到环氧树脂和固化剂中,制备了钨/环氧树脂辐射防护复合材料。通过扫描电镜、原位拉伸装置研究了钨含量80%(相对于整体质量而言)的钨/树脂基辐射防护复合材料的拉伸性能和微观组织演变。研究结果表明:钨含量80%的钨/环氧树脂辐射防护复合材料试样在拉伸过程中裂纹起始于材料中的钨粉团聚颗粒和气孔处,大量裂纹产生释放应力,较大的裂纹合并后试样发生断裂。硅烷偶联剂改性可以改善钨/环氧树脂复合材料的界面结合力,提升力学性能。改性后钨含量80%的钨/环氧树脂辐射防护复合材料的抗拉强度为8.49 MPa,最大应变为5.5%,大于纯钨的延伸率(3%),有利于加工成防辐射纤维材料。     

钨铼合金电化学溶解工艺研究

采用电化学溶解法对某钨铼合金废料在氢氧化钠电解体系中的溶解过程进行研究。考察了电流密度、电解液碱度、温度、电解液钨离子浓度对电解过程的影响。实验结果表明,在阳极电流密度400 A/m~2、氢氧化钠浓度300 g/L、电解液温度40～45℃的条件下平均槽电压为2. 5 V,合金电化学溶解率可达98%,使得大部分钨、铼以阴离子状态转入溶液中,完成钨铼合金的高效溶解,工艺简单高效,可实现工业化生产。     

钨青铜型(TB)材料

钨青铜型材料具有优异的铁电、压电、热释电、非线性光学性能而逐渐得到广泛的关注。本文从结构的角度上，对钨青铜型材料进行了分类介绍，并详细介绍了其中四方钨青铜材料的发展过程以及发展趋势。     

亚砜类萃取剂M-601分离钨钼

<正> 一、前言随着信息时代的到来,优质钨制品的需求量日益增加。降低钨中钼含量是制取优质钨制品的关键之一。由于钨、钼同属周期表中VIB 族,外层电子结构相同,化学性质相近,在自然界中钨、钼常在矿中共生,因此,从钨中分离钼,长期来一直是钨湿法冶炼中重要而困难的课题。目前工业上,从钨中分离钼一般采用硫化钠法。由于该法在实际生产过程中钨的损失较多,加上操作过程中产生有毒硫化氢气     

镍钨合金电沉积伏安特性和初期行为的研究

镍钨合金镀层由于其高的硬度、耐磨及耐蚀性而被作为代铬镀层用于金属表面处理。为进一步探讨镍钨合金的电沉积机理,采用循环环伏安法和电位阶跃法研究了玻碳电极上镍钨电沉积的循环伏安特性和初期行为。电沉积过程中,钨酸根被还原成中间价态的氧化物。     

复合电沉积铜-钨合金工艺及其机理的研究

分析了阴极电流密度、微粒的质量浓度、温度、搅拌速率等对铜-钨复合镀层中钨微粒的体积分数的影响。用扫描电镜观察正交优化工艺制备的复合镀层,结果表明:镀层电沉积结晶均匀、细致。此外,对复合电沉积铜-钨的过程机理进行了初步探讨,结果表明:在低电流密度条件下,铜-钨复合镀层的沉积遵循Guglielmi模型机理。     

不同基底非晶态镍钨合金电沉积中氢的作用

研究了三种材质基底上非晶态镍钨合金电沉积过程中阴极析出氢的影响．结果表明,玻璃碳中氢的吸收不可能发生,钯中氢的扩散和吸收是迅速的,镍的行为介乎其间．在玻璃碳上可以生成平整的、厚度较大的、有金属光泽的镍钨镀层,镍上也发现了沉积物,而钯上没有任何新相沉积,由此肯定了氢在镍钨合金诱导共析过程中的重要性．     

带壳B炸药在钨珠撞击下冲击起爆的数值模拟

基于L ee-T arver点火增长模型,对直径分别为9、14、18和25mm的钨珠撞击带钽壳B炸药的过程进行了数值模拟,计算出了引爆B炸药的阈值速度,计算值与试验值相符合。探讨了B炸药在钨珠撞击下的起爆机理,结果表明,随着钨珠尺寸的增大,引爆B炸药的钨珠撞击阈值速度呈指数规律减小;当钨珠以引爆阈值速度撞击炸药时,随着钨珠直径的增大,炸药发生爆轰的时间逐渐推后,爆轰增长速度逐渐变慢。从钨珠撞击引爆炸药的机制来说,炸药点火是压力波的峰值压力和持续时间共同作用的结果,峰值较低的压力波作用较长时间也可以引爆炸药。     

Effects of supercritical CO2 extraction parameters on chemical composition and free radical-scavenging activity of pomegranate (Punica granatum L.) seed oil

Pomegranate (Punica granatum L.) seed oil (PSO) was prepared by supercritical CO₂ (SC-CO₂) extraction technology. Changes in the yield, chemical composition and free radical-scavenging activity of PSO under different extraction parameters were investigated. The results of SC-CO₂ extraction revealed that extraction pressure was the dominant factor to affect the oil yield. PSO was characterized by a high content of punicic acid (approximately 60%) and γ-tocopherol (more than 300 mg/100 g oil). A slight increase in the contents of punicic acid, arachidic acid and gadoleic acid was observed under higher extraction pressure and temperature. At lower pressure or shorter extraction time, PSO with high amount of total tocopherols was obtained. PSO extracted by SC-CO₂ showed strong free radical-scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenz-thiazoline-6-sulfonic) diammonium salt (ABTS) radicals and its scavenging ability was correlated with the level of tocopherols in extracted oils.     

Oxidative Stability of Papaya Seed Oil From Hainan/Eksotika Obtained by Subcritical and Supercritical Carbon Dioxide Extraction

Papaya seed is a good source of edible oil with considerable antioxidant activity. Here, papaya seed oil (PSO) of Hainan/Eksotika variety was obtained by subcritical butane extraction (SBE) and supercritical carbon dioxide extraction (SCDE), and its yields, physicochemical properties, oxidative and thermal stability, and chemical and microscopic structures were compared. The results showed that SBE‐PSO had a higher yield (25.88 ± 0.29% vs. 19.47 ± 0.92%), but a lower melting point compared to SCDE‐PSO. Molecular structures indicated that there was no oxidative degradation during SBE and SCDE. Both SBE and SCDE caused significant structural changes of seed tissues. In addition, aldehyde composition analysis using high performance liquid chromatography (HPLC) showed that SBE‐PSO had fewer octanal, nonanal, 2‐decenal, and 2‐undecenal contents than SCDE‐PSO. All these results proved that SBE‐PSO exhibited superiority on the oxidative stability compared to SCDE‐PSO. It indicated that SBE was a superior method to obtain antioxidant edible oil with good stability.     

Improved extraction of penicillin G using hydrocarbon sulfoxides

Extraction of penicillin G with sulfoxide extractants, petroleum sulfoxide (PSO) and di‐isooctyl sulfoxide (DISO) was researched systematically. Based on research of the extraction equilibrium of penicillin G, the suitable extraction and re‐extraction conditions were determined, and then extraction cascade and bench‐scale experiments were carried out. The performance of extraction systems composed of PSO and DISO, with sulfonated kerosene as the diluent, is superior to that of n‐butyl acetate owing to the low solubility of these new extractants in water. Their consumption during the extraction process was lower, and the recovery step of extractants from aqueous raffinate was eliminated. Copyright © 2004 Society of Chemical Industry     

Effect of moisture and temperature on the phosphorus content of crude soybean oil extracted from fine flour

Analysis of total oil content in soybeans is usually done by extracting flours, whereas commercial extraction for recovery of oil is done by extracting flakes. It has recently become apparent that phosphorus content of crude soybean oil extracted from flours can vary depending on extraction temperature and flour moisture. In this study, flour moistures below 6% yielded crude oil with low phosphorus (15 ppm), but phosphorus in the oil increased rapidly to 260 ppm at 9% moisture. When temperature of the extraction was increased from 25 to 60°C, the phosphorus in extracted oil also increased for moisture contents of 6.6% and 8.3%, but not for moisture contents of 5% and 3%. In addition to the effects of extraction temperature, it was found that preheating whole soybeans at various temperatures affected phosphorus in oil from extracted flour. Preheating at 130°C caused high phosphorus content regardless of how dry the flour was, whereas preheating at 100°C or below caused phosphorus content that increased with increased moisture. The response of phosphorus content in crude oil to temperature and moisture may be useful in improving the quality of commercially extracted soy oil.     

盐湖提锂萃取剂及萃取体系研究进展

中国盐湖中蕴藏着丰富的锂资源,溶剂萃取法提锂是目前研究较多且较深入的方法之一。大量研究表明,萃取剂分子的结构是决定萃取效率的关键因素。对近年来盐湖卤水提锂萃取剂及萃取体系的研究进展做了综述,着重综述了醇+酮、有机磷、季胺盐-偶氮离子螯合-缔合、冠醚和离子液体等不同类型萃取剂及萃取体系的研究现状,分析了各类萃取剂在提锂过程中的机理、特点及存在的问题,并在此基础上对溶剂萃取法盐湖提锂萃取剂的发展方向做了展望。     

中国湿法磷酸净化技术（工程）进展情况

溶剂萃取法净化湿法磷酸技术的研究,是磷化工行业公认的重要课题。中国从20世纪70—80年代也开始了相关研究,但大都停留在实验室研究阶段。介绍了中国自主开发的溶剂萃取法净化湿法磷酸技术工程化的进展,包括工艺研究进展概述、工艺流程、特色及产品质量、成本估算等,以期为相关企业技术方案的选择提供参考。     

循环冷却系统污垢中无机磷提取方法优化

再生水中磷绝大部分为无机磷，是引起循环冷却系统结垢腐蚀的重要因素。为了探究无机磷在系统内的迁移转化及其对系统的影响，无机磷的定量定性尤为重要。在分析了无机磷的SMT( standard measurements and testing)连续提取法在循环冷却系统污垢提取中应用的可行性的基础上，对SMT提取方法进行条件优化，建立了污垢中无机磷定性定量分析方法。结果表明，优化后的SMT连续提取法能够实现对系统内污垢中无机磷的完全提取，且回收率接近100%；污垢中弱吸附态磷（NH₄Cl-P）、铝结合态磷（Al-P）、铁结合态磷（Fe-P）和钙结合态磷（Ca-P）4种形态无机磷能得到完全分离。     

胺类萃取剂萃取湿法磷酸中硫酸根的研究

采用胺类萃取剂对湿法磷酸进行脱硫研究。在固定磷硫比条件下,考察了酸浓度、相比（萃取剂与磷酸的体积比）、萃取级数和杂质（铁离子和氟离子）对硫酸根萃取率与五氧化二磷分配系数的影响。磷酸浓度降低、相比增加和萃取级数增加,均会导致硫酸根和五氧化二磷萃取率增加、分配系数提高。通过实验可知,当萃取相比为0.5、五氧化二磷质量分数为20%时,采用2级错流萃取有利于萃取硫酸根和减少五氧化二磷损失;对铁的选择性较差,但可以在脱除硫酸根的同时脱氟。     

Fabrication of fine microcapsulated red phosphorus particles by SCF-RESS with a new structure nozzle

A novel process of preparing microencapsulated red phosphorus particles by rapid expansion of supercritical fluids (RESS) was tested, in which a new kind of nozzle and supercritical CO₂ as a solvent were used. The structure of the microencapsulated red phosphorus particles were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). These results show that red phosphorus particles can be effectively encapsulated with paraffin by using the method. At the same time, how the moisture absorption ratio of microencapsulated red phosphorus particles was dependent on the experimental conditions was further investigated. The results suggest that paraffin-microencapsulated red phosphorus particles show a lower moisture absorption ratio within the experimental conditions of the extraction column and nozzle temperature of 120°C, extraction column pressure of more than 16 MPa, and a mass flow of core particles (0.5 g/min).     

[DIALKYLCARBAMOYLMETHYL] PHOSPHINE OXIDES ON THEIR EXTRACTION CAPACITY AND SELECTIVITY

Extraction of Am ( III), Pu( IV), U( VI) from nitric acid solutions by dialkyl ( aryl) [ dialkylcarbamoylmethyl] phosphine oxides of different structures has been studied.

The nature of substituents at phosphorus and nitrogen atoms and in methylene bridge affects extraction capacity, solubility and selectivity of reagents.

The increase in extraction capacity of reagents with respect to Am, U, Pu and decrease in solubility and selectivity at consecutive replacement of alkyl-( or alkoxy-) radicals at phosphorus atom by phenyl ones was found.

The advantage of reagents usage with two different radicals one of which is phenyl at phosphorus atom has been shown.

The nature of substituent at nitrogen atom affect solubility but does not practically affect extraction capacity of reagent.