氯化钠对氯化钾浮选的影响试验及浮选动力学模拟研究

针对浮选过程中氯化钠随氯化钾浮出问题,以KCl、NaCl、盐酸十八胺等作为试验材料,以XFD-0.5浮选机模拟浮选工艺,分别考察钠离子、镁离子和氯化钠颗粒对氯化钾浮选带来的影响及规律.结果表明:在不同捕收剂浓度下,钠离子对氯化钾的浮选影响不大,但氯化钠颗粒对氯化钾浮选的影响较大;在相同捕收剂浓度下,镁离子浓度的增加,会降低氯化钾的浮选回收率.同时以NaCl-KCl混合溶液中的氯化钠和氯化钾单盐浮选规律作为试验数据,建立浮选二级动力学模型和三参数快慢浮两速率常数模型,得出氯化钾浮选更适合采用二级动力学模型进行模拟,而氯化钠浮选更适用于三参数快慢浮两速率常数模型进行模拟.模拟结果表明:氯化钠浮选回收率与慢浮颗粒的质量分数有很大关系,慢浮颗粒质量分数越大,氯化钾浮选回收率越低.因此,在实际生产中可通过调节通气量的方式来降低慢浮的质量分数.     

氯化钾正浮选过程中杂盐氯化钠浮出现象的实验研究

氯化钾正浮选的理论研究表明在利用盐酸十八胺浮选时氯化钠不应浮出,但在实际生产时杂盐氯化钠仍有浮出的现象,降低了氯化钾精矿产品的品质。针对氯化钠随氯化钾同步浮出的问题,从浮选母液中的钠离子、原料中的氯化钠颗粒、浮选过程的气泡夹带及盐颗粒间粘附干扰浮选过程等方面分别考察了氯化钠对氯化钾正浮选的影响规律。结果表明：无论浮选母液是否存在钠离子,氯化钾浮选收率的差异都不显著;但是,当氯化钠与氯化钾的颗粒混合浮选时, 氯化钾的收率明显降低;当通气量增大时,氯化钠收率持续增大,使得氯化钾产品品质下降;根据扫描电镜和能谱分析可知,光卤石水解后浮选得到的精矿中同时含有氯化钾和氯化钠颗粒。综合可知,浮选母液中的钠离子对氯化钾浮选的影响可忽略,但是氯化钠颗粒可通过在浮选时阻碍捕收剂与氯化钾颗粒的接触、与氯化钾晶体颗粒粘附等方式干扰氯化钾的正浮选过程,并且当通气量较大时气泡对氯化钠颗粒的夹带也是促使氯化钠浮出的一个因素。这些实验结果从原料赋存状态和浮选过程角度解释了氯化钾正浮选过程中氯化钠非正常性浮出的原因,可以为实际钾盐正浮选生产过程的工艺优化提供参考。     

正浮选过程中氯化钠随氯化钾浮出行为的研究

在正浮选法制备氯化钾过程中,由于氯化钠与氯化钾一同浮出而影响了氯化钾产品的质量,因此有必要针对氯化钠随氯化钾浮出的行为进行研究。在25 ℃条件下,考察了氯化钠浓度对氯化钾-氯化钠和氯化镁-氯化钾-氯化钠两种浮选液黏度的影响,以及在这两种溶液中氯化钠的粒径对氯化钠的沉降速率、氯化钠的回收率、氯化钾产品质量的影响。结果表明,正浮选中氯化钠随氯化钾浮出的主要原因是浮选液的黏度较大,粒径较小的氯化钠颗粒易黏附于气泡表面或进入氯化钾矿化泡沫层而被夹带浮出。当氯化钠颗粒大于125 μm时,可有效减小氯化钠对氯化钾浮选的干扰,提高氯化钾产品的质量。     

十二烷基吗啉选择性浮选氯化钠颗粒的作用机理

通过研究十二烷基吗啉（DMP）在饱和卤水中对氯化钠颗粒的浮选行为,揭示了氯化钠颗粒通过增强体系泡沫的稳定性而提高了十二烷基吗啉的浮选性能;运用红外光谱法研究证明,DMP分子以物理作用力吸附于氯化钠颗粒表面;同时,研究了十二烷基吗啉分子在氯化钠颗粒表面的吸附行为及精光卤石颗粒与各种条件下氯化钠颗粒表面的接触角.研究结果表明,十二烷基吗啉选择性浮选分离氯化钠颗粒的作用原理是：十二烷基吗啉分子在饱和卤水介质中由于受到很强的疏水力,选择性吸附于氯化钠颗粒表面;且因精光卤石（KCl•MgCl₂•6H₂O）颗粒表面有很强的水合斥力,十二烷基吗啉分子不能吸附于精光卤石颗粒表面;因此,在浮选过程中,吸附在气泡界面的DMP分子因受到疏水作用力,使气泡吸附在氯化钠颗粒表面,氯化钠颗粒被浮选分离.     

丁黄药用作高硫铝土矿浮选除硫的捕收剂

采用浮选方法对我国含硫一水硬铝石型铝土矿进行脱硫,采用单因素实验研究了高硫铝土矿在浮选剂丁基钠黄药作用下反浮选除硫的工艺条件,考察了浮选剂用量、浮选时间、浮选矿浆浓度(液固质量比)、pH值及矿石粒度对浮选的影响. 结果表明,反浮选除硫的合适工艺条件为,矿浆pH 10、浮选剂用量0.16 kg/t、起泡剂20 g/t、浮选刮泡时间15 min、液固质量比10、矿石粒度0.15 mm. 在此工艺条件下,铝土矿中硫含量由2.08%降低到0.41%,符合我国氧化铝工业对矿石中硫含量的要求,Al2O3回收率达90.83%. 浮选过程基本符合一级动力学反应方程.     

不同活化剂对亚氯酸钠的活化效果研究

采用单因素实验,考察了硫酸氢钠、过硫酸钠、氨基磺酸、葡萄糖、氯化钠作为活化剂对亚氯酸钠制备二氧化氯的活化效果。在此基础上,通过正交实验得出活化剂的最佳配比:氨基磺酸浓度为3.00%,硫酸氢钠浓度为11.00%,葡萄糖浓度为0.75%,氯化钠浓度为1.50%。释放动力学实验研究表明,反应过程分为三阶段,第一阶段属零级反应,其动力学方程为:X_A=9.386 0 t+3.110 0;第二阶段为二级反应,其动力学方程为:1/X_A=-0.000 2 t+0.019 3;第三阶段为一级反应,动力学方程为:lnX_A=0.000 2 t+4.483 4。     

UASB处理高浓度有机食品废水运行特性研究

对升流式厌氧污泥床处理高浓度有机食品废水运行特性进行了研究,从进水COD、pH、挥发性脂肪酸含量、碱度及温度等方面分析了反应器的运行特性;并从反应动力学角度,得出进水COD(C0)与出水COD(Ce)的关系为Ce=C0e-0.0747t。     

浮选动力学模型研究进展及展望

为实现浮选的自动控制,提高浮选效率,介绍了浮选动力学模型的发展历程,论述了浮选动力学模型实例,分析了浮选动力学理论在金属矿物和煤泥浮选中的应用,并对浮选动力学模型发展趋势进行展望。由于浮选过程极其复杂,影响浮选分离的因素很多,现有的浮选动力学模型只是对某些重要影响因素进行模拟,无法将各种不均一性在同一模型中得到体现,对于许多复杂难选矿也不太适用。以浮选速率常数为基础,从浮选过程的微观机理出发,运用计算机模拟仿真技术,结合浮选动力学模型中参数的变化规律,是准确描述实际浮选过程的前提,也是未来浮选动力学研究发展的趋势。     

捕收剂GJBW作用下胶磷矿浮选动力学研究

以贵州省某海相沉积型胶磷矿纯矿物为研究对象,通过对纯矿物浮选及其动力学行为探索,研究了捕收剂GJBW质量浓度及矿物粒度对浮选动力学的影响。结果表明,胶磷矿的浮选动力学与一级动力学模型匹配度最高,同时在一定范围内捕收剂GJBW的质量浓度和颗粒的粒度均会对浮选动力学行为产生较大的影响。捕收剂GJBW质量浓度越高,各粒级的极限回收率ε∞越高,浮选速率常数k值越大;同时矿物粒度越大,极限回收率ε∞越小,而浮选速率常数k值却增大。     

萤石在油酸和水玻璃体系中的浮选动力学模型及浮选行为研究

在油酸和水玻璃体系中,进行了萤石纯矿物浮选试验。用3种经典的动力学数学模型对萤石浮选试验结果进行了数值拟合,并对拟合结果进行了误差分析。拟合结果表明,萤石浮选过程符合经典一级浮选动力学模型,浮选速率常数平均值k=0.29,导出方程为:ε=ε!1(-ε-0.29t)。考察了萤石粒度、浮选药剂用量、浮选矿浆质量浓度、浮选机叶轮线速度等因素对萤石浮选回收率ε和浮选速率常数k值的影响。试验结果表明,油酸用量和浮选矿浆质量浓度的增大均有利于萤石浮选速率常数k值的提升,水玻璃用量的影响较小。细粒级萤石的浮选速率常数k值高于粗粒级萤石,但回收率ε逐渐降低,当粒度小于0.010mm时,萤石浮选效果很差。随着浮选机叶轮线速度v的提高,萤石浮选回收率ε和k值均逐渐增大,有利于萤石的浮选回收。     

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。