首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
湿法磷酸副产物氟硅酸直接生产得到的高分子比冰晶石,含有一定量的二氧化硅,有时高达1%(质量分数),若要达到产品合格标准则必须进行脱硅处理。通过理论分析了产品中二氧化硅含量高的成因及脱除思路,将产品经过酸洗涤、碱洗涤、高温煅烧等方法进行脱除处理实验,并分析二氧化硅的脱除效果及对产品的影响。最终得到合格的高分子比冰晶石产品,得出氢氟酸浸泡及400 ℃高温煅烧处理能得到二氧化硅合格的高分子比冰 晶石。  相似文献   

2.
采用二次中和法制备了沉淀水合二氧化硅,并通过单因素实验对产品的比表面控制影响因素进行了研究,得出较优的影响因素组合为反应温度为40 ℃,酸质量浓度为70 g/L,碱质量浓度为110 g/L,两段加酸量比例(酸液前期配合量占总配合量的比例)为70%,反应时间在60~120 min,搅拌速率在40~300 r/min。同时结合生产经验,发现影响因素的组合影响产品比表面积的规律,从而通过准确控制沉淀水合二氧化硅比表面积达到控制产品质量的目标。  相似文献   

3.
刘晓红  张琪 《硅酸盐通报》2016,35(2):651-654
以磷肥生产过程中的副产物氟硅酸为原料制备高纯二氧化硅.氟硅酸与氨水反应,得到氟硅酸铵溶液,加入铵盐沉淀钙镁离子,再加入钙盐沉淀铝铁离子,静置后过滤得到净化的氟硅酸铵溶液;将净化液氟硅酸铵与氨水反应生成二氧化硅沉淀,经过滤、热洗、干燥、煅烧,得到高纯二氧化硅.样品SiO2符合国标要求.实验表明,以氟硅酸制备高纯二氧化硅工艺可行.工艺特点是将低附加值的氟硅酸转化为高附加值的高纯SiO2,铵盐钙盐除杂适宜,反应步骤少、过程简单、操作条件温和.  相似文献   

4.
黄磷炉渣制取硫酸钙的实验研究   总被引:1,自引:0,他引:1  
以黄磷炉渣为原料,经HNO<,3>溶液浸出,SiO<,2>以无定形水合二氧化硅的形式分离,钙元素以Ca(NO<,3>)<,2>的形式进入到浸出液,浸出液经H<,2>SO<,4>沉淀,然后经洗涤、干燥可得到优质的CaSO<,4>产品.讨论了H<,2>SO<,4>质量分数、H<,2>SO<,4>与Ca(NO<,3>)<,2...  相似文献   

5.
通过液相化学沉淀法采用水合二氧化硅对TiO2进行了表面包覆,对包覆过程的温度、pH值、包覆量对产品颜料性能的影响进行了系统研究,并对其机理进行了分析。结果表明,水合二氧化硅的沉积量(质量分数)随温度的升高而增加,膜层形态发生变化,且在碱性环境下明显高于酸性环境。水合二氧化硅适宜的沉积条件为pH=9.5,80℃,沉积量为2%—3%,此时沉积率可达到77%,产品的综合颜料性能较好。  相似文献   

6.
针对HG/T 3061—2009《橡胶配合剂沉淀水合二氧化硅》中二氧化硅含量和胶料拉断伸长率指标值以及在水合二氧化硅(白炭黑)胶料物理性能测试中使用标准参比白炭黑提出了一些具体的修订建议。分析认为:现行ISO 5794-1:2010在我国应用时其白炭黑的二氧化硅(灼品)质量分数指标上限偏小(0.97),适宜值为0.98;现行HG/T3061—2009的白炭黑胶料拉断伸长率的A类指标(测试值法)偏大(550%),建议调整为520%。通过代表性白炭黑生产企业对白炭黑产品的质量判定表明,白炭黑胶料物理性能的B类指标(差值法)和C类指标(比值法)测试因为采用了标准参比白炭黑,这两类指标较A类指标更科学、更合理,更具质量控制和工艺指导意义,值得大力推行。  相似文献   

7.
用油页岩渣制备白炭黑的工艺   总被引:7,自引:0,他引:7  
以油页岩渣为原料,经950℃煅烧4 h, 加入3.30 mol/L NaOH溶液于100℃处理4 h,用HCl酸化至pH 8~9时,SiO2的浸出率为75.8%. 经X射线荧光分析,白炭黑产品中的SiO2纯度为91.8%;经FT-IR检测白炭黑的化学结构为水合二氧化硅;经XRD分析,白碳黑为无定型结构;TEM图像显示白炭黑的形貌近似为球状粒子,平均粒径在50 nm以下. 白炭黑的比表面积(BET)为114 m2/g, pH值为5.5~6.0,加热减量为5.82%, 1000℃灼烧减量为6.16%,产品符合中国行业标准HG/T 3061-1999的要求.  相似文献   

8.
陈荣 《无机盐工业》2004,36(4):45-46
研究了以水玻璃和硫酸为原料合成沉淀法白炭黑(即沉淀水合二氧化硅)的反应条件。研究发现:反应温度、反应时间、硫酸质量分数、搅拌速度、水玻璃模数对白炭黑的比表面积或DBP吸收值有不同程度的影响。结果表明:改变反应条件,可以合成产品性能具有较大差异性的系列化产品,从而扩大白炭黑的应用范围。  相似文献   

9.
研究了以水玻璃和硫酸为原料合成沉淀法白炭黑(即沉淀水合二氧化硅)的反应条件。研究发现:反应温度、反应时间,硫酸质量分数、搅拌速度、水玻璃模数对白炭黑的比表面积或DBP吸收值有不同程度的影响。结果表明:改变反应条件,可以合成产品性能具有较大差异性的系列化产品,从而扩大白炭黑的应用范围。  相似文献   

10.
法国《橡胶与塑料综合志》1980.№601,63页报道:法国Rhone—Poulenc公司研制的微颗粒状Ze-O-Si 175产品是一种经沉淀获得的水合二氧化硅。这种补强填料所具有的特性能为橡胶提供卓越的性能(表1):  相似文献   

11.
12.
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.  相似文献   

13.
14.
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.  相似文献   

15.
16.
17.
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.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号