低温碱溶法提取粉煤灰中二氧化硅和氧化铝的实验研究

粉煤灰是排放量最大的固体废物,它的主要化学成分为SiO_2和Al_2O_3。采用碱溶法提取粉煤灰中的SiO_2和Al_2O_3,实验发现碱溶液的浓度、用量及反应时间等因素直接影响SiO_2和Al_2O_3的提取率,在优化实验条件下可提取出近30%的SiO_2,而Al_2O_3的溶出量小于3%。脱硅后的灰渣铝含量明显升高,同时可得到纯度较高的SiO_2,有一定的实用价值。     

硅酸盐固体废弃物应用的研究进展Ⅰ——粉煤灰应用研究新成果

粉煤灰是典型的硅酸盐固体废弃物。对近年来以粉煤灰为主要原料制备矿物聚合材料、合成沸石、制备微晶玻璃与多孔陶瓷、制备复合催化材料、提取Al_2O_3和SiO_2以及粉煤灰用作环境材料、高分子材料填料的研究进展进行了综述,讨论了当前研究存在的主要问题和特点。已开展的新应用技术研究包括:大体量消耗粉煤灰应用技术(如粉煤灰矿物聚合材料),高附加值制品(如微晶玻璃、多孔陶瓷及β-sialon粉体)的工艺研究;发掘粉煤灰潜在的性能优势(如火山灰活性),有效利用化学组分(如粉煤灰提取Al_2O_3和SiO_2),进行表面改性及其复合加工技术;粉煤灰终端利用途经的研究(如高分子材料填料),以及清洁加工和循环利用工艺的探索(如用作环境材料)等。与传统的应用途经(如粉煤灰水泥、粉煤灰混凝土)相比,新应用技术还不够成熟,有待进一步开发研究,以加快新应用技术的规模化、工业化生产进程。     

不同负荷下循环流化床锅炉粉煤灰的理化性质研究

为拓展循环流化床锅炉粉煤灰的利用途径,开发粉煤灰综合利用技术,研究了不同负荷下循环流化床(CFB)锅炉粉煤灰的粒径分布、化学组成、物相组成、Al_2O_3溶出特性和微观形貌等理化性质,考察了锅炉负荷对粉煤灰理化性质的影响。结果显示,CFB锅炉负荷对粉煤灰的粒径分布、化学组成和物相组成等性质影响较小,对粉煤灰中Al_2O_3溶出率影响较大,Al_2O_3溶出率与样品颗粒的微观形貌有关,颗粒表面孔隙和裂缝越多,Al_2O_3溶出率越高。CFB锅炉粉煤灰中的无定形相含量较高,在70%以上;CaO在粉煤灰中的主要存在形式有3种:硬石膏、生石灰和无定形CaO。Al_2O_3均是以无定形氧化物的形式存在,煤样中的Al_2O_3在燃烧过程中更容易以飞灰的形式排出;石英和硬石膏更容易以底渣的形式排出。     

复合生料无光釉的研制

叙述了复合生料釉的研制过程,讨论了MgO、CaO、ZnO、Al_2O_3、SiO_2等氧化物及Al_2O_3/SiO_2比、烧成制度和其他因素对无光釉的影响。     

高碳粉煤灰代粘土配料生产小结

我厂是一条年产4。4万吨的水泥生产线,利用电厂粉煤灰代粘土配料,采用全黑生料煅烧,生产325号、425R水泥。十几年来,出厂水泥合格率及富裕系数合格率均达到百分之百,并将电厂粉煤灰变废为宝,收到了良好的经济和社会效益。一、严格控制原材料的进厂存放及使用我厂原材料的特点:一是粉煤灰Al_2O_3偏高(20～28%),SiO_2含量偏低(40～55%),高碳粉煤灰的Al_2O_3含量19～24%,SiO_2含量34～45%,而烧失量变化无常。二     

以粉煤灰和赤泥为原料烧结陶瓷工艺与性能研究

本文研究了在1050 ℃至1200 ℃之间温度对以粉煤灰赤泥为原料烧结陶瓷的物相和烧结性能的影响.结果表明:实验用粉煤灰原料的主要矿相组成为石英(SiO_2)和莫来石(3Al_2O_3·2SiO_2),赤泥原料的主要矿相组成有钙铝黄长石(Ca_2Al_2SiO_7)、石英(SiO_2)、钙铁榴石(Ca_3Fe_2+3(SiO_4)_3)和钙钛榴石(Ca_3TiFeSi_3O_(12));以粉煤灰赤泥为原料的5组不同配比试样在1200 ℃时试样气孔率相对降低,体积密度和抗压强度相对程度增大;其中5#试样在经1200 ℃烧结后的气孔率为1.67%,体积密度为2.10 g·cm~(-3),抗压强度为123.23 MPa,达到较好的烧结致密状态,试样主要物相是钙钠长石和莫来石.试样内莫来石的形成及玻璃液相的增加促进烧结并在1200 ℃达到致密烧结状态.     

用煤渣配料及作水泥混合材

从1971年至今,我厂利用粉煤灰(煤渣)配制生料和作混合材,生产了325号与425号水泥。现简要介绍于下。一、用煤渣代替粘土配料生产水泥通常需用粘土来满足熟料中SiO_2,Al_2O_3成份。煤渣和粘土的化学成份有些相似,而其中 Al_2O_3的成份比粘土高,SiO_2的成份比粘土低。由于我厂本地石灰石品位     

酸浸法制备硫酸铝时铝矾土矿的筛选

我国铝矾土矿属于高铝、高硅、低铁类矿,是酸浸法制备硫酸铝的良好原料。属于高铝、高硅的铝矾土矿主要有以下一些种类:蓝晶石Al_2O_3SiO_2、红栓石Al_2O_3SiO_2、硅线石Al_2O_3SiO_2、霞石(Na、K)_2OAl_2O_32SiO_2、长石(Na、K)_2OAl_2O_3·6SiO_2、白云母K_2O·Al_2O_3·6SiO_2·2H_2O、绢云母K_2O·3Al_2O_3·6SiO_2·2H_2O、白榴石K_2O·Al_2O_3·4SiO_2、高岭石Al_2O_3·SiO_2·2H_2O等。一水软铝石Al_2O_3H_2O、一水硬铝石Al_2O_3H_2O、三水铝石Al_2O_3·3H_2O等是属于高铝低硅的     

粉煤灰提取氧化铝技术研究现状及工业化进展

我国铝土矿资源不足,铝矾土需求量不断增加,从粉煤灰尤其是高铝粉煤灰中提取Al2O3可有效补充我国铝资源量。分析了不同粉煤灰提取Al_2O_3工艺(酸法提铝、碱法提铝、碱烧结-酸浸出联合提铝技术)的特点、不足及工业化发展现状,探讨了粉煤灰提铝需解决的关键问题,并指出未来发展方向。酸法提铝工艺具有流程简单、能同时溶出Si、Al及其他元素等优点,但存在对提铝设备要求较高,废酸产量大、溶出率低等问题;碱法提取Al_2O_3工艺相对成熟,但存在硅钙渣产量大、能耗较高、成本高等问题,严重制约了其工业化发展;碱烧结-酸浸出联合提铝工艺可实现Al_2O_3的高效提取,但存在工艺复杂,强酸、强碱消耗大,Al_2O_3与Fe、Ti等杂质离子的分离较为困难等缺点。未来应优化完善现有提铝工艺,重视高附加值硅产品协同开发,重视粉煤灰中微量元素的提取和高附加值利用。低能耗、低成本、高效率、无二次污染产生是粉煤灰提铝技术的重要发展方向。     

成纤性粉煤灰的低熔区组成及分布

粉煤灰的熔融温度分布图对粉煤灰成纤的降熔配比具有指导意义。利用X荧光光谱仪和灰熔点测试仪,分别测得5种不同来源粉煤灰样品的组成和熔融特性温度。运用实验所测值与117种粉煤灰组成及熔融温度的文献值,以Al_2O_3+SiO_2、CaO+Mg O、Fe_2O_3+TiO_2为三相坐标制成三元相图,按照熔融温度高低划分不同区域,得到粉煤灰熔融温度分布图,找出低熔区(流动温度FT1350℃)的组成及其组成与熔融温度的分布规律。同时将次要组分通过等电量换算后标在CaO-Al_2O_3-SiO_2三元相图中,发现所研究粉煤灰在低熔区的组成与CaO-Al_2O_3-SiO_2三元相图中1350℃低温共熔区的组成具有良好的一致性,由此找出高熔融温度粉煤灰成纤的降熔调配方法。     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008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、不饱和聚酯树脂、环氧树脂)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.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006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生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。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（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。