中低品位磷矿及磷尾矿的综合利用现状

磷是一种不可替代的非再生资源,也是构成生命体必不可少的元素之一。简要概述了世界和中国磷资源的分布及开采利用情况,以及中低品位磷矿及磷尾矿的综合利用现状。建议加强中低品位磷矿直接利用的产业化集成技术以及磷尾矿清洁高效利用技术研发,实现磷资源的可持续利用,保障国家粮食安全生产。     

中低品位磷矿及磷尾矿高效清洁利用集成技术应用前景展望

针对现有中低品位磷矿选矿技术存在的磷回收率及磷精矿品位偏低、磷尾矿堆存带来巨大环境风险等问题,开发了中低品位磷矿及磷尾矿煅烧、硝酸铵浸出钙镁制取高品质低镁磷精矿及回收高纯钙镁产品集成技术。该技术无新的尾矿产生及废水排放,磷回收率大于99%,磷精矿P_2O_5品位高达36%～38%、MgO质量分数为0.3%～0.8%,可以满足磷矿湿法及热法深加工对磷精矿品质的要求;回收的高纯碳酸钙、氢氧化镁产品为下游深加工创造了良好条件。该技术为构建磷钙镁一体化产业链提供了有力的技术支持,形成了中低品位磷矿及磷尾矿高效清洁利用的绿色环保工艺。     

中低品位磷矿浮选尾矿制备磷镁肥的实验研究

研究开发一种以中低品位磷矿浮选尾矿为原料,采用硫磷混酸直接分解浮选尾矿制备磷镁肥的方法。阐述了浮选尾矿的矿物特性,硫磷混酸分解浮选尾矿制备磷镁肥的基本原理、工艺条件、产品质量,论证了中低品位磷矿浮选尾矿制备磷镁肥的可行性。     

一种磷尾矿富集并联产高纯度轻质碳酸钙和氢氧化镁的新技术

<正>成果简介中国磷矿贮量居世界第二位,但80%的贮量是中低品位磷矿,其中多为难选的中低品位胶磷矿。随着磷矿资源的大量开采,尤其是弃贫采富开采方法的普遍使用,使得P2O5质量分数在30%以上的富矿迅速枯竭。目前,要实现磷矿资源的综合利用和中国磷化工产业的可持续发展,攻克中低品位胶磷矿前处理技术和磷尾矿再利用技术势在必行。     

中低品位磷矿制取工业磷酸新技术

目前世界磷矿资源正在逐步贫化,尤其是我国磷矿资源绝大部分为中低品位磷矿,因此,研究中低品位磷矿制酸技术,搞好中低品位磷矿的加工利用,是关系到磷化工产业可持续发展的重大问题。     

综合利用磷矿浮选尾矿制磷镁肥料

我国人口众多,人均资源相对匮乏,虽然生产磷肥的磷矿资源丰富,但90％以上是中低品位磷矿,主要依靠选矿技术提高品位才能使用。目前,我国中低品位选矿技术水平,可将P2O5质量分数从22％磷矿提高到30％,磷损失约15％～20％,浮选尾矿一般为P2O5质量分数8％-10％。若浮选磷矿装置为100万t／a,则尾矿达35万t／a,其损失P2O5达8万t／a。     

利用中低品位磷矿生产优等品钙镁磷肥

介绍昆阳磷矿钙镁磷肥厂利用中低品位磷矿生产优等品钙镁磷肥的工业试验和生产和生产实践的情况。利用中低品位磷矿代替高品位磷矿生产优等品钙镁磷肥,为大量中低品位克矿资源的合理利用找到了一条行之有效的途径。     

磷矿浮选尾矿的综合利用途径

中低品位磷矿选矿过程产生大量的磷尾矿,合理开发利用磷尾矿既可产生一定的经济效益,又可避免磷尾矿堆存占用土地及危害环境。对磷尾矿在水泥熟料、二元复合肥、窑法磷酸、微晶玻璃等方面的综合再利用情况进行了阐述。     

中低品位磷矿综合利用研究进展

在高品位磷矿资源紧缺、环境问题日益受到关注的情况下,合理利用中低品位磷矿是我国应对磷矿危机的有效途径。概述了中低品位磷矿在农业、工业和生物领域中应用的研究进展,指出高效、节能、环保的中低品位磷矿利用技术将是今后发展的重点。     

中低品位磷矿前处理技术的研究进展

主要介绍了中国中低品位磷矿前处理的紧迫性、重要意义及前处理技术方法种类、发展现状、存在的主要问题,针对所存在的问题,提出了中低品位磷矿硝酸铵-硝酸混合法前处理技术及其基本过程、优势,为中低品位磷矿开发利用提供了一条合理可行的途径,同时提出了硝酸铵-硝酸混合法在含磷尾矿中的拓展应用意义,为进一步解决磷资源枯竭、环境污染等问题,找到了一个可取的发展方向。     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.