磷矿石浮选精矿沉降试验研究

通过对磷矿石浮选精矿在清水和回水中进行沉降试验,研究了产品沉降的影响因素,结果表明,添加絮凝剂TFB能有效提高沉降效果,矿浆pH值及水质对沉降也有一定影响。     

不同絮凝剂对高泥氧化铜浸出液沉降的影响

为解决云南某氧化铜现场生产中酸浸矿浆含泥量高、沉降速度慢、固液分离困难的问题,对其浸出矿浆进行絮凝沉降实验研究. 实验用浸出矿浆浓度为28.73%,考察了絮凝剂种类、用量、浓度对矿浆沉降的影响. 结果表明,明矾、十二烷基丙磺酸钠、聚丙烯酰胺、明胶、改性阴离子型聚丙烯酰胺、改性阳离子型聚丙烯酰胺均不能有效改善沉降速度,而改性非离子型聚丙烯酰胺(GH-6C)可使矿浆沉降速度大大加快. 这是由于GH-6C分子链上的官能团与浸出液中的胶体粒子发生吸附架桥作用,使颗粒逐渐变大而絮凝沉降. GH-6C分子量较大,在水相中流体力学尺寸或体积也较大,絮凝网捕能力也大,可有效降低絮凝剂的使用浓度、提高絮凝效率. GH-6C浓度为0.1%、用量为0.067 g/L时,沉降指标较好.     

絮凝剂提高疏浚泥浆泥水分离性能研究

为了考察絮凝剂对疏浚泥浆泥水分离效果的影响,以当涂姑溪河疏浚泥浆为研究对象,选用8种絮凝剂通过量筒静置试验观测泥浆静态脱水效果,确定最佳絮凝方案并研究不同泥浆浓度情况下絮凝剂的投加量及沉降效果,并在动态试验中结合经济性统筹选择最佳方案.结果表明,疏浚泥浆含泥量为5％时,最佳絮凝剂为PFS,其投加量为200 mg/L时沉...     

煤泥水沉降特性试验研究

三河尖选煤厂煤泥水沉降效果差,以该选煤厂的浓缩机入料煤泥为研究对象,基于煤泥性质分析,选用不同种类的凝聚剂和絮凝剂进行了一系列煤泥水沉降试验,研究了煤泥水质量浓度、凝聚剂和絮凝剂用量对煤泥水沉降效果的影响。结果表明:原煤变质程度低、煤泥粒度细和黏土矿物的存在会加大煤泥水的处理难度;煤泥水质量浓度为70 g/L时,PAC和1 000万分子量PAM是最佳药剂组合,最佳用量分别为780、15 g/t,此时煤泥水沉降效果最好,上清液浊度为18 NTU,沉降速度为11.16 cm/min。絮凝剂和凝聚剂添加量对煤泥水沉降效果影响显著,而煤泥水浓度小范围变化对处理效果无明显影响。     

小纪汗选煤厂煤泥水沉降性能试验研究

为了探讨相关因素对煤泥水絮凝沉降过程的影响规律,研究制定针对小纪汗选煤厂煤泥水处理过程中的加药策略,对该厂煤泥水进行了沉降性能试验;结果表明,煤泥水中微细颗粒较多,絮凝剂浓度对该煤泥水絮凝沉降效果影响较大;随着絮凝剂浓度的增加,初始沉降速度先增大后减小,当絮凝剂浓度为10 g/m~3时,初始沉降速度最大;絮凝剂浓度一定时,初始沉降速度随凝聚剂与絮凝剂质量比的增加而不断增大。     

河南某浮选精矿絮凝沉降性能的研究

针对河南某浮选精矿微细粒多,沉降困难,循环水固含高,导致浓密池冒槽跑浑严重的问题进行了添加絮凝剂改善沉降状况的试验。主要进行了絮凝剂的种类筛选、添加方式、用量等工艺制度的试验。结果表明,在用量为22.09g/t时,絮凝剂2#、絮凝剂3#能够起到良好效果。其中,絮凝剂2#适用于一次添加方式,絮凝剂3#在累次添加方式下效果更为显著。絮凝剂2#的底流压缩比较高,但是絮凝剂3#的上清液比较清。浮选精矿中絮凝剂的添加提高了浮选精矿的沉降速度,降低了循环水的固含,显著提高了循环水的利用率,在保证良好选矿指标的前提下,确保了整个工艺的有效运行。     

阳离子型DF/PAC复合絮凝剂处理活性印染废水

针对印染厂生产废水,以COD和色度为指标,用混凝试验方法,研究了碱化度为1.6的聚合氯化铝(PAC)和黏度为560mPa·s的双氰胺-甲醛缩聚物(DF)以及阳离子型DF/PAC复合絮凝剂对活性印染废水的处理效果.考察了絮凝剂的沉降效果和絮凝剂的投加量及投加方式对絮凝脱色效果的影响,探讨了废水pH值对阳离子型DF/PAC复合絮凝剂絮凝脱色性能的影响.结果表明,DF/PAC可有效地去除印染废水中的COD和色度,当pH为6～9、沉降时间为35min、投药量为1.0mg/L时,去除效果最佳,COD去除率≥90%,脱色率≥99%;相对于PAC和DF,DF/PAC产生的絮体大而密实,沉降速度快、产生污泥量少,药剂用量少,出水水质为:COD<80mg/L,色度<30倍.     

裂化催化剂生产废水中悬浮物的去除试验

用配制的分别以阴离子聚丙烯酰胺、氯化铝和阳离子聚丙烯酰胺为主剂的三种絮凝剂对裂化催化剂生产废水进行絮凝研究,考察了絮凝剂的加入量、废水pH值和絮凝沉降时间对絮凝沉降效果的影响。试验结果表明:在一定的操作参数下,以阴离子聚丙烯酰胺为主剂絮凝剂的用量较少,效果最好。     

崇明岛河道典型河段疏浚底泥絮凝脱水试验研究

含水率高是目前河道疏浚底泥资源化利用的最大瓶颈。该文以崇明岛老滧河疏浚底泥(底泥C)及赢东村东湖底泥(底泥Y)为研究对象,研究了3种絮凝剂对不同底泥的沉降和脱水效果,为两种不同底泥最佳絮凝剂的选择提供依据,同时,通过不同絮凝剂投加量、含水率、反应时间和搅拌强度的试验,为实际工程提供优化参数。结果表明:1#絮凝剂对底泥C的沉降效果最好,其投加量为2%(絮凝剂与底泥干重之比);3#絮凝剂对底泥Y的沉降效果最佳,其投加量为1%;底泥C和底泥Y的最适疏浚含水率分别为380.0%和305.0%,最适搅拌强度分别为80 rpm和40 rpm,最佳絮凝时间均为30 min。     

祁东矿选煤厂煤泥水处理系统优化改造

针对祁东矿选煤厂循环水浓度高,分选效果差,压滤机排料周期长,原煤入选量减少等问题,采用不同种类、用量的絮凝剂和助滤剂分别进行煤泥水絮凝沉降试验和尾煤压滤试验,并对现场加药系统和加药点进行优化。结果表明,絮凝剂TLT8634添加量为6 m L时,煤泥水沉降时间最短为8 s,煤泥压缩高度为100 mm,上清液澄清度为15,满足生产需要;助滤剂TLT5140用量为300 g/t时,抽滤时间与空白样相比缩短53.44%,水分降低2.58%。选煤厂絮凝剂加药点改为三点加药,点与点间隔0.5 m;助滤剂改为在煤泥管道三点加药,药剂混合更加充分。煤泥水系统优化后絮凝剂和助滤剂的药剂成本由1.96元/t降至1.4元/t,每年可节省药剂费用约110万元,循环水质量浓度保持在1g/L以下,实现了煤泥水闭路循环。     

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.     

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.     

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。