高磷铁矿含碳团块直接还原-磁选提铁

采用直接还原?磁选工艺从湖南某地高磷铁矿含碳团块中提铁,研究了还原温度、还原时间、团块碱度、还原剂焦粉用量、添加剂Na2SO4用量和废塑料替代焦粉量等因素对磁选精矿指标的影响. 结果表明,在还原温度1150℃、还原时间40 min、团块碱度0.8、碳氧摩尔比0.9的条件下,添加4% Na2SO4同时添加废塑料替代25%焦粉,可得到金属化率为88.77%的焙烧矿,磁选后可得到铁品位91.99%、金属化率92.26%及P含量0.20%的金属铁粉,铁回收率达86.74%.     

褐铁矿的煤泥球团直接还原

以煤泥为还原剂,考察了其种类及用量、还原温度与时间以及CaCO3添加量等对褐铁矿中铁氧化物直接还原的影响,研究了不同条件下还原产物中铁矿物的存在形式,考察了添加剂用量对含碳球团熔融分解的影响. 结果表明,煤泥C还原效果最好,其用量30%,CaCO3添加量3%,在1250℃下直接还原30 min,含碳球团金属化率达94.02%. 铁在产物中主要以金属铁颗粒存在,粒度多大于30 mm,添加3% CaCO3使渣铁分离效果明显,有利于产物分离. 表明煤泥是一种良好的褐铁矿还原剂.     

无烟煤直接还原铜渣中铁矿物工艺研究

铜矿经熔炼等工序提取铜后,渣中的铁元素含量通常超过30%(质量分数)。直接还原-磁选制备金属铁是利用铜渣中铁资源的有效途径。以无烟煤为还原剂,用正交实验和单因素实验考察了焙烧温度、焙烧时间、碳铁物质的量比、碱度等因素对铁金属化率的影响。结果表明铁金属化率随焙烧温度、焙烧时间、碳铁物质的量比、碱度的增加先增加后基本保持不变,各因素影响铁金属化率的顺序为焙烧温度焙烧时间碳铁物质的量比碱度。无烟煤直接还原铜渣的工艺条件:焙烧温度为1 100℃,焙烧时间为90 min,碳铁物质的量比1.4,碱度为1.6。在此条件下铁金属化率达到91.84%。     

低品位难选菱铁矿煤基还原试验研究

在分析低品位难选新疆菱铁矿性质的基础上,进行了直接还原-熔融还原一步炼铁试验研究,考察了还原时间和温度、煤用量对金属化率的影响规律及碱度对铁收得率、渣铁分离效果的影响规律.结果表明:在一定范围内,增加还原时间和温度,提高碳氧比有利于直接还原铁金属化率和熔融还原渣铁分离后铁收得率的提高;高碱度配料可以实现渣铁分离.通过XRD和SEM对配加氧化钙的渣进行了矿物相和形貌分析,对渣的活性进行了讨论.     

以硅铁为还原剂制取金属锂的工艺优化

以硅铁为还原剂,采用真空热还原法制备金属锂. 通过单因素实验及正交实验研究了还原温度、反应时间、制团压力、物料粒度、真空度及还原剂过量率等因素对金属锂还原率的影响. 结果表明,在实验范围内各因素对还原率的影响次序为：还原温度>还原时间>还原剂过量率>制团压力>物料粒度. 硅热真空还原制备金属锂的最佳工艺条件为：还原温度1293 K,还原时间180 min,制团压力30 MPa,物料粒度80 mm,还原剂过量率50%. 在该条件下金属锂的还原率可达97.85%,纯度达99.24%.     

生物质还原磁化褐铁矿的实验研究

研究了广西崇左褐铁矿磁性转化和还原机理. 通过生物质与褐煤焙烧还原褐铁矿的对比实验,考察了焙烧温度、焙烧时间、原料配比等工艺条件对矿物磁性的影响. 结果表明,生物质还原的最佳焙烧温度为650℃左右,焙烧时间30 min,生物质用量为15%~20%. 结合XRD分析结果,确定以褐煤及生物质还原铁矿主要得到磁性Fe3O4及g-Fe2O3,温度高时易转化成硅酸铁,影响后续磁选回收铁.     

某难选菱铁矿石直接压球及还原焙烧

将某难选菱铁矿石破碎到粒度小于2 mm后,加入一定量粘结剂和内配煤与矿石压制成型后再还原焙烧,通过对成球条件、直接还原焙烧过程影响因素和磨矿磁选条件进行实验,确定了最佳条件,最终可得到铁品位92.76%、回收率为85.97%的直接还原铁产品. 结果表明,粒度小于2 mm的菱铁矿石压球后直接还原可得到高品位、高回收率直接还原铁,还原过程中球未发生粘结、碎裂、膨胀等现象,还原状态良好.     

加入聚乙烯的含碳铁矿球团的直接还原

以包头地区褐铁矿和无烟煤为主要原料,加入聚乙烯颗粒制成含碳铁矿球团,直接还原制备珠铁. 考察了还原温度、还原时间、配碳量及聚乙烯加入量对含碳铁矿球团直接还原的影响. 结果表明,影响含碳铁矿球团还原率的因素为还原温度、还原时间、配碳量、聚乙烯加入量. 最佳还原条件为C/O摩尔比1.2,加入聚乙烯量4%(w), 1350℃下保温5 min. 该条件下产物还原率最高,达99.87%. 加入一定量聚乙烯可缩短球团还原时间、降低还原温度、提高还原效率. 添加2% CaF2不仅使渣铁分离效果明显,且分离的渣可自然粉化,有利于筛分得到高品质珠铁.     

温度对贵州某鲕状赤铁矿气基(H_2)还原的影响

文章主要研究了不同还原温度下,鲕状赤铁矿的气基还原。运用光学显微镜、XRD和化学分析等手段对鲕状赤铁矿在不同还原温度下矿相、物相和金属化率进行了表征。结果表明:金属化率随着还原温度的增加而增加,在还原温度为1100℃,还原时间为120 min时,金属化率可达到86.75%,同时鲕状结构也被破坏掉。还原过程中形成的Fe Al2O4阻碍了铁元素的还原反应。     

回收高炉尘泥中的铁与锌

利用高炉尘泥以还原焙烧-磁选工艺获得高品位富铁矿,由醋酸回收液回收还原后的锌得到高纯度醋酸锌产品. 研究得出合理的焙烧工艺条件是：温度1373.2 K、时间60 min. 通过还原焙烧,高炉尘泥脱锌率可达98%,并得到含锌率仅为0.04%(w)、金属化率高的还原矿. 还原矿在150 mT的磁场强度下弱磁选可得铁品位在80%左右的富铁矿,回收液经浓缩结晶后得到纯度达98.7%的醋酸锌副产品. 所得富铁矿和醋酸锌可工业应用.     

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.     

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。     

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.     

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。