水泥矿山锤式破碎机PC2425的提产改造

金隅冀东水泥某公司的石灰石破碎车间使用一台PC2425锤式破碎机 （见图1）,转子规格Φ204000mm×205000mm,出料粒度≤700mm,筛余5%,生产能力在950~100000t/h。业主为了提高生料磨的产量及降低生料粉磨的电耗[1],将出料粒度控制在500mm以下。业主通过调整篦条与锤头的间距及篦条间隙达到了降低出料粒度的要求,但是台时产量急剧降低到8000t/h,已无法满足生产需求。受业主委托,对锤式破碎机PC2425进行提产改造。     

破碎机篦笼的改造

<正>我公司4 500t/d生产线由于石灰石易磨性差,邦德功指数较高,导致生料立磨产量低、能耗高,不能满足窑的需要。2011年3月份,立磨平均产量179.68t/h,电耗28.75k Wh/t。为此,对PSJ-2425破碎机进行改进,降低破碎机的出料粒度,以提高磨机产量。1破碎机篦笼的改造PSJ-2425破碎机的设计破碎能力:入料粒度800~1 000mm,产量800~1 000t/h。篦笼由前后两件组     

锤头尺寸超差导致减产的分析

<正>我公司三条5 000t/d生产线石灰石破碎系统配置了两台PCF2022单段锤式破碎机,出料粒度65mm以下,合格率80%以上,产量可稳定在780t/h左右。但2号破碎机在2014年5月3日更换锤头后,产量一直加不上去。产量加到约650t/h时,给料辊电动机就     

三级石灰石破碎机的安装与效用

随着熟料及水泥产量的提高,要求生料磨的台时产量相应增加。但由于多种原因,目前尚不能采用改开流磨为闭流磨的作法,而最现实的措施是用降低入磨粒度的方法来提高磨机产量。为此,进行了有关的可行性分析研究: ①因原有的石灰石破碎系统是为一条3.2万t/a水泥生产线所设计的,能力很小。后来为满足两条8.8万t/a水泥生产线的需要而对其进行了改进,主要措施是增大二级破碎机的出料粒度(见《四     

冲击式破碎机故障的应急处理

我公司两条5 000t/d生产线辅料破碎系统采用两台型号为CJ2 1100×1280的冲击式破碎机,破碎能力200～300t/h,喂料粒度≤500mm,出料粒度≤50mm(90％).2012年2月1日其中一台破碎机破碎腔内进入一条长600mm的槽钢,卡在转子与反击滚筒之间,造成下部的反击滚筒断轴及转子体局部撕裂的恶性事故.为了尽快恢复正常生产,我们采取更换反击滚筒,对转子体采用局部修补的方法进行修复.     

φ2.2m×6.5m球磨机台产攻关

我公司生料车间有两台φ2.2m×6.5m球磨机,设计能力为16t／h,经过几次小型改造,台时产量最高仅18t／h,并且不够稳定。公司为了降低成本,决定对生料磨机进行台产攻关。1 问题分析 (1)入磨物料粒度过大 入磨物料粒度的大小直接影响磨机的产量,我公司原二级破碎机为PYBφ1200圆锥破碎机,其出料粒度>25mm 占50％。粒度≤10mm的占10％。出料间隙调小,则破碎机经常撞壁,潮湿物料又经常堵塞,因此粒度始终降不下来。     

一种破碎搭配预均化的方法

为节省投资，金塔公司2500t／d生产线未采用石灰石预均化堆场。由于矿点较多且质量参差不齐，并受交通整治、矿山安全整顿及气候等多种外界因素影响。石灰石难以均衡进厂。无法在新线破碎机下料口搭配破碎，使得入磨石灰石质量变化较大，出磨生料合格率低，造成入窑生料成分不稳定。同时因所用石灰石中SiO2含量高，使得新破碎机产量低、锤头磨损快，出料粒度大且不均匀，严重制约了生料磨台时产量的提高。为解决这一问题，经研究决定试用湿法生产线停产后闲置的老线破碎系统破碎10％～20％的外购石灰石，新线破碎系统则破碎80％～90％的本公司矿山及北坑石灰石。     

2PCF2025双转子锤式破碎机篦子改造

某公司采用出料篦缝为45mm、设计能力为900~1　100t/h的2PCF2025双转子破碎机,由于出料篦条磨损严重,提高产量后加剧磨损,无法保证正常生产,只能维持在600t/h进行破碎,而且更换篦子频繁,影响生产,制约了整条生产线的运行。对此我公司与用户深入交流,在现场观察磨损情况和磨损类型,提出了切实可行的设计方案,并取得了良好的使用效果。     

振动筛在二级破碎前的应用

我公司的熟料由PEX150×750颚式破碎机进行破碎,其出料粒度最大的为40mm,平均粒度为20mm,严重影响水泥球磨机的台时产量.因此我公司新购进一台2PDG800×1000型双辊破碎机,作为二级破碎.该破碎机的主要参数为:入料粒度≤60mm,出料粒度3～15mm,产量为10～50t/h,电机功率2×30kW.但在使用过程中,对辊破碎机的出料粒度调节到10mm时,其台时产量还不足30t/h,即二级破碎出料粒度和产量都满足不了水泥球磨机的需求(我公司1#线为两台Φ2.2×6.5m球磨机,闭路系统,原入磨熟料粒度平均直径为20mm时,单台产量为15t/h).     

φ3m×11m水泥磨改造

我厂以电石渣为主要原料生产水泥,年设计能力25万t,配备一台准3m×11m磨机,2001年投入运行的一年中,产量低,比表面积也不理想。为此,我们对粉磨系统先后做了几项改造,收到了良好的效果。1原系统配置湿法回转窑生产的熟料平均粒度在20m m左右,未经破碎直接入磨。磨机为三仓圈流磨钢球。级配情况见表1。隔仓板及出料篦板的篦缝尺寸:大端16m m,小端6m m。选用N H X—800高效转子式选粉机;产量:28￣32t/h;比表面积:270￣300m2/kg。2改造内容及效果2.1降低入磨熟料粒度在熟料入磨前加一台LC P35离心冲击式破碎机,并配备筛分装置。破碎后的熟料…     

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.     

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.