硫酸酸浸法除磷石膏中杂质氟的研究

以H2SO4为浸取剂对磷石膏进行热浸取,考察磷石膏中杂质氟的去除情况,为磷石膏综合利用提供基础数据。研究在均匀设计实验的基础上,进一步考察了温度、时间、硫酸质量分数、含固量(质量浓度)、粒度5个因素对杂质氟去除率的影响规律。结果表明:温度、时间、硫酸是影响氟去除率的主要因素,而含固量、粒度对结果影响较小。较理想的除氟条件为浸取温度88℃,浸取时间45 min,H2SO4质量分数30%,含固量0.43 g/mL,在优化实验条件下杂质氟的去除率可以达到84.50%,处理后的磷石膏含氟仅为0.036%。采用硫酸酸浸处理磷石膏,杂质氟去除效果好,且提高了净化磷石膏的白度。     

从复合固体推进剂中浸取高氯酸铵的动力学过程

为了探索以水为介质从复合固体推进剂中浸取高氯酸铵(AP)的动力学过程,分析了AP在水中的浸取过程,比较了不同浸取温度和试样厚度条件下AP的浸取平衡分离常数及其回收率,用SEM观察了浸取后的推进剂试样内部结构.结果表明,浸取速率常数随温度提高和推进剂试样厚度的减小而增大.浸取温度及试样厚度一定时,速率常数是定值,浸取速率...     

湿法磷酸脱氟渣中磷和氟的浸取回收

脱氟渣是湿法磷酸在脱氟过程中产生的废渣,其中含有价值的磷、氟。为回收脱氟渣的磷,研究了浸取法分离脱氟渣中磷、氟的工艺。分别以水、碳酸钠溶液作为浸取剂,考察了不同的浸取时间、pH值、温度、液固比及2级浸取条件下,脱氟渣中P_2O_5、F的浸出率和浸出液的磷氟比(P_2O_5/F)。结果表明:在水浸取体系,适宜的条件是浸取时间为30 min、液固比为2∶1、温度为30℃,P_2O_5和F的浸出率分别为92.38%、11.56%,浸出液的P_2O_5/F为9.54;在碱浸取体系,适宜的条件是浸取时间为30 min,液固比为3∶1、pH值为3.8、温度为25℃,P_2O_5和F的浸出率分别为75.68%、1.49%,P_2O_5/F为61.36;二级浸取能减少浸取剂的用量,并有效地降低F的浸出率。将水浸出液浓缩能有效地提高P_2O_5/F,可以得到饲料级MCP生产所需的磷酸。     

离子选择电极法测定磷石膏中全氟含量

磷石膏中的氟限制了磷石膏在水泥和建材等领域的应用,因此了解磷石膏中的氟含量非常重要.对磷石膏中的氟含量的测定方法进行了探讨.通过实验提出了用碳酸钠熔融磷石膏样品,用柠檬酸钠-冰醋酸作为总离子强度调节缓冲溶液,采用离子选择电极法测定磷石膏中的全氟含量.该方法氟离子质量浓度检出限为0.34 mg/L,氟离子回收率为88.5%～90.3%,氟离子质量浓度线性范围为0～5 mg/L,线性相关系数R2=0.999 1,相对标准偏差为1.2%(n=7).该方法是一种简便、快捷、灵敏度较高的测定磷石膏中全氟含量的方法.     

浸取中和法脱除磷石膏中杂质的研究

以硫酸为浸取剂对磷石膏进行热浸处理,采用石灰乳中和调节磷石膏酸度,考察了反应温度、反应时间和硫酸浓度对磷石膏中杂质磷、氟、铁和铝的脱除情况的影响。同时,采用扫描电镜、热重分析仪和X射线衍射仪分析了处理前后磷石膏形貌、热稳定性和晶型结构的变化。结果表明：温度为85 ℃,硫酸质量分数为30%,反应45 min时,磷和氟的脱除率均能达到90%左右,铝脱除率能达到80%,铁脱除率大于20%,石膏pH≥7.0。处理后的石膏粒径减小非常明显,热稳定性有一定提高,且晶型更加稳定,能够完全满足建筑材料的要求。     

有机溶剂浸取湿法磷酸脱氟渣制备磷酸的研究

脱氟渣是湿法磷酸化学沉淀脱氟过程产生的固体废渣。分别用甲醇、乙醇和丙酮浸取脱氟渣来回收脱氟渣中的磷酸,研究了浸取时间、温度和液固比对于五氧化二磷、氟的浸取率以及浸出液磷氟比［m（五氧化二磷）/m（氟）］的影响,得到了适宜的浸取条件。浸取液经蒸发浓缩回收浸取剂后,浓缩液均可满足饲料级磷酸氢钙生产对于湿法磷酸磷氟比的要求。综合考虑浸取剂成本、五氧化二磷浸取率和浸出液磷氟比,确定甲醇为优选浸取剂,并用响应面法对甲醇浸取工艺条件进行优化。优化工艺条件下五氧化二磷的浸取率为97.13%、浸出液磷氟比为51.62,甲醇在5次循环回收利用后对脱氟渣仍有较好的浸取效果。     

铵盐浸取风化壳淋积型稀土矿中稀土和铝的动力学研究

为了探究铵盐浸取剂的使用,揭示稀土和杂质的浸出规律,以硫酸铵、氯化铵和硝酸铵分别作为浸取剂,考察温度、铵根离子浓度和流速对风化壳淋积型稀土矿中稀土和铝浸出动力学的影响,并采用收缩未反应芯模型对浸出过程进行拟合。结果表明,在一定范围内提高温度、铵根离子浓度或流速均可提高稀土和铝的浸出速率。硫酸铵浸出速率最慢、氯化铵次之,硝酸铵最快,且铝的浸出速率均略慢于稀土。稀土和铝的浸出过程受内扩散控制,浸取反应活化能大小依次为硫酸铵氯化铵硝酸铵,稀土铝。浸取反应活化能越大,表观速率常数越低,反应级数越高。该结果可为风化壳淋积型稀土矿的高效开采提供理论指导。     

磷石膏制硫酸铵的反应机理与动力学实验研究

研究了磷石膏制取硫酸铵的反应机理与本征动力学速率方程,通过理论研究与实验论证发现,上述反应是在磷石膏与碳酸铵的固液界面上进行的,符合缩芯模型。在动力学速率方程参数的测定中,由于磷石膏微溶于水,反应速率近似地认为只与碳酸铵的浓度有关,实验是在低温、低碳酸铵浓度、高搅拌速率以及磷石膏过量的条件下进行的,实验得到了温度为0,5,10℃时的速率常数,同时将不同温度的速率常数进行拟合得到了磷石膏与碳酸铵反应的活化能为37 246.64 J/mol,指前因子为77 033.83 min-1。     

高品质磷石膏处理工艺研究

综合利用磷石膏对治理环境和资源循环利用具有重大意义.磷石膏中的五氧化二磷、氟、有机物等杂质影响磷石膏的利用.为了得到高品质磷石膏,研究了用硫酸浸取磷石膏的反应条件,如硫酸质量分数、反应温度、反应时间及液固比等因素对磷石膏中酸不溶五氧化二磷含量的影响.通过单因素分析和正交实验设计,确定了最佳工艺条件.最佳工艺条件为:硫酸质量分数35%;反应温度60℃;液固体积质量比为3 mL/g;反应时间4.5 h.在此条件下磷石膏中酸不溶五氧化二磷质量分数降低到0.01%以下.     

硫酸处理磷石膏改性脱磷工艺研究

磷石膏的综合利用,对环境安全、资源有效利用及磷肥工业可持续发展的技术安全均具有巨大的商业价值和现实意义.磷石膏中的五氧化二磷、氟、有机物等杂质影响磷石膏的利用.为简便、经济、环保地除去磷石膏中的磷,研究了用硫酸浸取磷石膏的反应条件,如硫酸质量分数、温度、时间及液固比等因素,及其对磷石膏中不溶五氧化二磷质量分数的影响.通过单因素分析和正交试验设计,确定了优化工艺条件.优化工艺条件参数为:硫酸质量分数为20%;反应温度为80℃;液固体积质量比为2 mL/g;反应时间为4.5 h.在此条件下处理后的磷石膏中五氧化二磷质量分数减少约99%,降低到0.005%以下.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、环氧树脂、不饱和聚酯树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍。     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。