硅钙钾土壤调理剂造粒烘干工艺研究

硅钙钾土壤调理剂(硅钙钾肥)是一种绿色环保、缓释长效的新型矿物肥料,具有提供养分和调理土壤的双重功效。以硅钙钾肥为研究对象,试验研究其造粒烘干工艺和设备。试验研究结果表明:湿球筛分有助于细粉成球,降低烘干能耗;烘干时应尽量减少颗粒的振动,以降低碎球概率;设置2组收尘器,分别用于回收干粉尘和含水汽粉尘;设置二次造粒有助于提高颗粒强度。     

改性纳米碳酸钙对淀粉胶粘剂剪切强度的影响

以木薯淀粉为原料,经氧化后制成淀粉胶粘剂,并利用纳米碳酸钙的补强作用改善淀粉胶粘剂的强度性能,实验结果表明:加入改性纳米碳酸钙的淀粉胶粘剂的干强度和湿强度分别提高了0.764MPa和0.366MPa,改性纳米碳酸钙的加入能更显著地提高淀粉胶粘剂的干强度和湿强度。     

酸解乙酰化淀粉胶粘剂的制备及性能研究

以玉米淀粉为原料,采用酸解乙酰化淀粉与醋酸乙烯酯(VAc)接枝共聚的方法,通过优化工艺参数,制备了酸解乙酰化淀粉胶粘剂。研究结果表明:当V(VAc)=30 m L、w(醋酸酐)=6%和w(引发剂)=2.5%(均相对于淀粉干基质量而言)时,胶粘剂的干态、湿态剪切强度相对最大(分别为3.70 MPa和2.10 MPa);酸解乙酰化淀粉胶粘剂的流动性和灰分含量均优于白乳胶,并且其对木材无污染性,而且其冻融稳定性和粘接强度稳定性俱佳。     

利用畜禽粪便发酵生产商品有机肥料的工艺研究

适合西北地区的有机肥好氧发酵方式有槽式发酵和条跺式发酵,一般情况下可选择条跺式发酵,冬季可将物料暂时储存。有机肥的造粒过程从干、湿程度上可分为干法造粒和湿法造粒,湿法造粒又可分为盘式造粒和平模挤压造粒。干法造粒投资少,但粉料多、颗粒强度小;湿法盘式造粒制得的产品颗粒均匀、强度大,但成球率低、投资大;湿法平模挤压造粒成球率高、颗粒强度大,但投资高、耗能大、设备不便于维修。对于资金不足的小型有机肥生产企业宜采用干法挤压造粒工艺,资金充足的有机肥生产企业可采用湿法盘式造粒工艺。     

聚乙烯醇改性淀粉胶粘剂的研究

聚乙烯醇在一定条件下与玉米淀粉接枝共聚，可以提高玉米淀粉胶粘剂的粘接强度和干燥速度，再用高锰酸钾氧化剩余的淀粉，得到的玉米淀粉胶粘剂中再加入合适的催干剂，极大地提高玉米淀粉胶粘剂的干燥速度。     

玉米淀粉基胶粘剂的制备及性能表征

以玉米淀粉和丙烯酰氯为主要原料,制得酯化淀粉;然后将其与VAc(醋酸乙烯酯)进行接枝共聚,制得酯化淀粉基木材胶粘剂。采用红外光谱(FT-IR)法对酯化淀粉的结构进行了表征,并着重探讨了酯化淀粉中丙烯酰氯含量对胶粘剂的强度、黏度等影响。研究结果表明:酯化淀粉的预期结构被成功合成,相应胶粘剂的干态剪切强度、湿态剪切强度和黏度均随酯化淀粉中丙烯酰氯含量增加而提高;当w(丙烯酰氯)=3%(相对于酯化淀粉质量而言)时,胶粘剂的储存稳定性相对最佳。     

变性淀粉接枝丙烯酰胺复配可乳化MDI制备木材胶粘剂

以马铃薯氧化淀粉为原料、过硫酸钾(KPS)为引发剂和丙烯酰胺(AM)为接枝单体,制备AM接枝氧化淀粉主剂;然后将主剂与可乳化MDI(二苯基甲烷二异氰酸酯)复配,制备木材淀粉胶粘剂。研究结果表明:制备主剂的最佳工艺条件是m(马铃薯氧化淀粉)∶m(AM)=3.0∶1、反应温度为70℃、反应时间为120 min和引发剂加入时间为40 min;由最佳工艺条件制成的主剂与可乳化MDI复配后,相应木材淀粉胶粘剂的干(湿)态胶接强度明显提高;可乳化MDI掺量可根据胶接强度要求而定,但不宜超过6%(相对于主剂质量而言)。     

乳化剂十六烷基三甲基溴化铵对木材用淀粉胶粘剂使用性能的影响

研究了乳化剂十六烷基三甲基溴化铵(CTAB)的添加对木材用淀粉胶粘剂粘接性能、黏度、流动性、贮藏稳定性的影响,并对其作用机理进行了初步探讨。结果表明,CTAB的添加会导致木材用淀粉胶粘剂压缩剪切强度的小幅下降,但可以降低淀粉胶粘剂的黏度,明显改善玉米淀粉胶粘剂的流动性,提高淀粉胶粘剂的贮藏稳定性;CTAB添加量以占淀粉干基质量1.5%为宜,其所改性的木材用淀粉胶粘剂具有良好的使用性能。差示扫描量热仪(DSC)和扫描电子显微镜(SEM)分析可知,CTAB的作用机理可能是阻碍了淀粉分子的聚集,从而抑制了淀粉的短期回生和长期回生。     

乳化剂十六烷基三甲基溴化铵对木材用淀粉胶粘剂使用性能的影响

研究了乳化剂十六烷基三甲基溴化铵（CTAB）的添加对木材用淀粉胶粘剂粘接性能、粘度、流动性、贮藏稳定性的影响,并对其作用机理进行了初步探讨。实验结果表明,CTAB的添加会导致木材用淀粉胶粘剂压缩剪切强度的小幅下降,但可以降低淀粉胶粘剂的粘度,明显改善玉米淀粉胶粘剂的流动性,提高淀粉胶粘剂的贮藏稳定性;CTAB添加量以占淀粉干基质量1.5%为宜,其所改性的木材用淀粉胶粘剂具有良好的使用性能。差示扫描量热仪（DSC）和扫描电子显微镜（SEM）分析可知CTAB的作用机理可能是阻碍了淀粉分子的聚集,从而抑制了淀粉的短期回生和长期回生。     

生物质炭基复混肥造粒用淀粉胶粘剂的合成条件研究

以淀粉为主要原料、H_2O_2(过氧化氢)为氧化剂、FeSO_4(硫酸亚铁)为催化剂、硼砂为交联剂和硫代硫酸钠为稳定剂,采用正交试验法优选出淀粉胶粘剂的合成条件,进而优选出BCF(生物质炭基复混肥)造粒用胶粘剂的最佳工艺条件。研究结果表明:当m(淀粉)=30 g、氧化温度为45℃和V(H_2O_2)=2.5 m L、氧化阶段10%NaOH(氢氧化钠)溶液4 m L、糊化阶段10%NaOH溶液8 m L和糊化温度为65℃时,制得的胶粘剂之黏性和流动性俱佳;当m(炭粉)∶m(尿素)∶m(磷酸二氢钾)∶m(胶粘剂)≈4∶1∶1∶1时,BCF颗粒的成粒率(为95.60%)和压缩强度(为0.026 MPa)相对最高。     

LDPE细粉产生的原因及控制措施

分析了低密度聚乙烯(LDPE)细粉产生的可能原因:LDPE在生产过程中挤出切粒不良,颗粒脱水干燥,气力输送碰撞摩擦,颗粒外观不良等。通过加强相关设备管控,控制LDPE颗粒外观,选择合适的气力输送系统,增加除尘设备等措施,可以减少和降低最终产品中的细粉含量,对LDPE质量提升有一定借鉴意义。     

氧化淀粉粘合剂的合成及其在新型肥料中的应用

通过正交试验确定了合成氧化淀粉粘合剂的最佳工艺及对粘合剂粘度影响显著的因素,分析了粘合剂的稳定性和生物毒性,同时对其在新型肥料中的应用做了一定研究。试验结果表明:氧化剂用量和温度对粘合剂的粘度影响显著,粘合剂的稳定性好、无生物毒性,粘度为30mPa．s的粘合剂成粒性能最好。     

Steady states in granulation of pharmaceutical powders with application to scale-up

Theoretical and experimental evidence is given to show that steady states can be reached during agglomerate growth and break-up in high-shear granulation of fine powders. An earlier theoretical model [G.I. Tardos, I.M. Khan and P.R. Mort, Critical parameters and limiting conditions in binder granulation of fine powders, Powder Technology, 94, 245-258 (1997).], based on simple energy-dissipation considerations hinted at the existence of these states at the point where growth is counterbalanced by breakage. Further theoretical evidence is obtained from molecular dynamic simulations of wet and dry particles situated in a constant shear field [I. Talu, G.I. Tardos and M.I. Khan, Computer simulation of wet granulation, Powder Technology, 110, 59-75 (2000).], where the size distribution of initially identical particles, shifts in time to reach a dynamic steady state. Under the conditions of this steady state, the number of breaking agglomerates approximately equals the number of forming ones to yield a time independent final-size distribution.Experimental evidence to support the theoretical findings is obtained during the present research by measuring particle size distributions at line at crucial points during granulation of a typical pharmaceutical powder in a high-shear mixer. In order to reach a steady state, binder addition has to be slow enough and wet massing has to be long enough so that neither has an influence on the final properties of the granules. We show experimentally that if binder is spread properly and homogeneously in the powder and continuous shearing of the wet mass ensures homogeneous, equal growth of the granules, the steady state will only be a function of the total amount of fluid added provided that the shear forces in the machine are maintained constant.These findings are important in that they show that under carefully controlled conditions of binder addition and shear in the mixer, the granulation process is robust and controllable and can, in principle, be scaled up with ease once the powder ingredients and the total amount of binder are fixed.     

氮化铝粉末的制备及扩大实验研究

主要进行了碳热还原法制备氮化铝粉末扩大实验研究。研究了不同的铝源、碳源、氮化温度、保温时间、添加剂对合成氮化铝粉末的影响,并采用XRD、SEM、化学物理分析等手段对中试实验制备的氮化铝粉末进行分析。研究结果表明,采用经砂磨处理的铝源B（α-Al₂O₃）和3^#碳源（乙炔黑）为原料,有助于碳热还原反应;采用添加剂C可以降低反应活化能,提高氮化率;造粒工艺有助于扩大实验的碳热还原反应。     

橡胶硫化促进剂N-环己基-2-苯并噻唑次磺酰胺的团粒法造粒技术

采用团粒(聚)法制备了橡胶硫化促进剂N-环己基-2-苯并噻唑次磺酰胺(CBS)粒状产品,确定了团粒造粒工艺的最佳条件,并在此条件下进行了稳定运行实验.结果表明,用脱水后含水率为20%的CBS湿粉料为造粒原料,采用团粒法制备CBS粒状成品的最佳工艺条件:黏结剂乙烯-乙酸乙烯酯共聚物质量分数为CBS干基料的8%、湿粒含水率为34.77%,造粒盘倾角为35～45°、造粒盘转速为65 r/min,黏结剂乳液喷加时间约为10 min,造粒周期为50～60 min,烘箱干燥温度为(55±2) ℃,烘干时间为210 min;在最佳工艺条件下制得的粒状CBS性能均达到指标要求:初熔点不小于96.0 ℃,粒径为2.0～4.5 mm,粒子的平均强度在2.0～8.0 N,加热减量不大于1.00%,灰分不大于0.40%,成粒率超过60%.该粒状CBS能完全取代粉状产品,对橡胶的硫化性能无不良影响.     

Synthesis and flash sintering of zirconium nitride powder

Zirconium nitride (ZrN) is a transition metal nitride of great interest due to its excellent physical and chemical properties. This study aims to synthesize ZrN fine powders by a facile and low-cost urea route that avoids the use of any solvent. ZrCl₄ and urea mixtures were heat-treated at up to 1600˚C in nitrogen gas. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. The effects of different processing parameters such as metal to urea molar ratio, heat treatment temperature, and dwelling time on the product phase and stoichiometry were studied to understand the synthesis method. In addition, synthesized ZrN powder was consolidated into near fully dense single-phase bulk ceramic with a homemade flash sintering setup. A constant DC electrical field of ∼80 V/cm and pressure of ∼14 MPa at room temperature triggered flash sintering without pre-heating, and the entire process finished in 200 s. The composition, microstructure, density, hardness, and oxidation properties of the sintered pellet were also characterized.     

Process intensification in particle technology: Characteristics of powder coatings produced by nonisothermal flow‐induced phase inversion

The characteristics of powder coatings manufactured through a novel processing technique based on nonisothermal Nlow‐induced phase inversion granulation enhanced by fluid injection to promote phase inversion and particle formation from melt state is summarized. Experiments were carried out in a purpose‐built granulator, which operates in a parallel disk rotor‐stator arrangement, so that the mechanism of granulation could be studied. The product of this intensive granulation was compared with that of the conventional powder coating manufacturing process. Understanding the mechanism of intensive granulation helped to redesign the equipment that resulted in smaller particles. Pigment dispersion characteristics were improved by intensive granulation. Also, the particle size span can be significantly reduced by dry granulation and gas‐phase granulation, and the flowability can be improved by wet granulation. Chemical analysis of particles by Fourier transform infrared spectroscopic analysis showed that the injection of coolant fluid had no effect on the chemical composition. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

焦炭粉冷固成型用粘结剂——改性水玻璃的研制

探讨了聚丙烯酰胺 ,葡萄糖 ,高岭土 ,Al Cl3,腐植酸钠 ,水溶性苯酚 -甲醛树脂和自制的水溶性树脂 A(简称为树脂 A)等对水玻璃改性的影响。结果表明 ,树脂 A使焦炭粉冷固成型的球团的生球和干球强度明显提高 ,并确定了其较佳配方 :水与水玻璃的质量比为 4∶ 6,其总用量为 16% (占干焦炭粉的质量分数 ) ;树脂 A用量为0 .2 4% (占干焦炭粉的质量分数 )。在此较佳条件下 ,所制球团的生球和干球强度 ,与用未改性水玻璃 (其中水与水玻璃的质量比为 3∶ 7) ,其总用量为 16% (占干焦炭粉的质量分数 ) )所制球团的生球和干球强度 ,几乎相等 ,但前者球团的耐水性以及耐热性有明显提高。     

Dense and homogeneous MOX fuel pellets manufactured using the freeze granulation route

MOX fuels (UO₂-PuO₂) are used in light water nuclear reactors of several countries and are also potential candidates for the fast neutron reactors. Industrial MOX is currently manufactured by a dry route process, involving steps with fine powders. To reduce dusting, enhance MOX powder flow properties, and decrease manufacturing scrap rate, a new wet route process is investigated: the freeze granulation of concentrated water-based powder suspensions having optimized rheology and dispersion properties. Highly flowable, dustless, and easy-to-press MOX granules have been elaborated. Sintering green compacts made of such granules gives highly dense and defect-free pellets that have a very homogeneous U-Pu spatial distribution, thus improving the fuel characteristics. Indeed, MOX fuels devoid of large Pu-rich aggregates are thought to have a better behavior under irradiation in reactors by limiting/preventing the formation of the typical high burnup structure.