溶胶-水热法制备亚微米4A分子筛

以湿硅胶和铝矾土为原料,采用溶胶-水热法合成了亚微米4A分子筛.采用X射线衍射(XRD)、扫描电镜(SEM)和红外光谱(FT-IR)等分析手段对溶胶-水热法制备的亚微米4A分子筛进行表征,并与常规水热法进行对比.结果表明:采用溶胶-水热法制备的产品结晶度为96%;产品形状规则,大小均匀、单一,呈正态分布且分布范围较窄;产品粒度较小,粒径≤1 μm粒子体积分数可达到100%;4A分子筛(干基)钙离子(以碳酸钙计)交换容量为335 mg/g,白度为97%,完全满足洗涤助剂的要求.     

溶胶-水热合成法制备纳米4A分子筛

以磷肥行业副产的含氟硅胶为原料,采用溶胶-水热合成法成功制备纳米4A分子筛,并采用XRD、SEM、激光粒度分析等手段与常规水热合成的4A分子筛进行了对比。结果表明,纳米4A分子筛钙交换容量为325mg/g,白度为95%,可满足洗涤助剂的要求。     

4A分子筛合成及在牙膏中应用

采用水热法制备粒度均匀的亚微米4A分子筛；利用离子电极法测最合成4A产品对氟离子的吸附效果．其吸附能力可达8mg／g．改变条件可调节吸附、释放适量氟；研究了合成产品与香料香精的配伍性．结果表明：4A分子筛能起到控制吸附、缓释香料香精的作用，结合4A分子筛具有适宜的硬度，满足磨擦剂应具备的基本要求，可以作为磨擦剂在牙膏工业中得到应用。     

高岭土合成4A分子筛及其在牙膏磨擦剂中的应用

以苏州高岭土和氢氧化钠为原料,通过水热法合成了4A分子筛,产品粒度细小、分布均匀;利用离子电极法测量合成的4A分子筛对氟离子的吸附效果,其吸附能力可达8 mg/g,改变条件可调节吸附、释放适量氟;而且,4A分子筛能起到控制吸附、延缓释放香精香料的作用;4A分子筛具有适宜的硬度,满足磨擦剂应具备的基本要求。     

4A分子筛的合成及其在牙膏磨擦剂中的应用

采用水热法制备了粒度均匀的亚微米4A分子筛,较佳工艺条件是：n（SiO2）／n（Al2O3）为1、9、n（Na2O）／n（SiO2）为1、6、n（H2O）／n（Na2O）为40,导向剂量为反应物料摩尔比的5％,90℃晶化1．5h;利用离子电极法测量合成4A产品对氟离子的吸附效果,其吸附能力可达8mg／g,改变条件可调节吸附、释放适量氟;研究了合成产品与香料香精的配伍性,结果表明：4A分子筛能起到控制吸附、缓释香料香精的作用,结合4A分子筛具有适宜的硬度,满足磨擦剂应具备的基本要求,可以作为磨擦剂在牙膏工业中得到应用。     

粉煤灰提取硫酸铝的残渣制备4A分子筛

利用粉煤灰酸法提取硫酸铝的残渣为原料,采用固相合成法进行4A分子筛的合成.并对其制备工艺条件和产品性能进行了实验研究,得到相应的较佳工艺条件为:粉煤灰酸渣∶氢氧化铝∶氢氧化钠=10∶4∶15;焙烧温度800 ℃～860 ℃,焙烧时间2 h～3 h;凝胶形成温度为55 ℃,时间2 h;晶化温度90 ℃～95 ℃,时间4 h～6 h.并对产品进行了XRD,SEM及IR等结构表征,与标准4A分子筛进行比较,结果显示所合成的产品为4A分子筛.     

高岭土水热制备洗涤助剂用4A分子筛

以高岭土为原料,水热法制备4A分子筛,采用SEM和XRD等对其进行表征,并考察碱化温度、碱化时间、晶化时间和晶化温度对4A分子筛制备的影响。结果表明,在碱化温度55 ℃、碱化时间3 h、晶化温度95 ℃和晶化时间6 h条件下,可获得粒径小于3 μm的4A分子筛。产品的钙离子交换容量为317 mg·g-1,白度为95,完全满足用作洗涤助剂的要求。     

4A分子筛合成研究

本实验主要以化学原料、高岭土和凹凸棒石粘土为原料,通过酸化,碱化,成胶,晶化这一工艺过程,利用传统水热法成功合成了4A分子筛,并通过微波法进行对比。实验过程使用光学显徽镜进行观察;产品通过X射线粉末衍射、NEXUS670型傅里叶红外光谱仪进行了表征。结果表明,传统水热法与微波法均能合成出4A分子筛,并且微波法合成出的样品粒度小且均匀,合成时间大幅减少,降低了能耗。     

4A分子筛的合成及其在牙膏磨擦剂中的应用

采用水热法制备了粒度均匀的亚微米4A分子筛，较佳的工艺条件是：n（SiO2）／n（Al2O3）为1．9、n（Na2O）／n（SiO2）为1．6、n（H2O）／n（Na2O）为40，导向剂量为反应物料摩尔比的5％，90℃晶化1．5h；利用离子电极法测量合成4A产品对氟离子的吸附效果，其吸附能力可达8mg／g，改变条件可调节吸附、释放适量氟；研究了合成产品与香料香精的配伍性，结果表明：4A分子筛能起到控制吸附、缓释香料香精的作用，结合4A分子筛具有适宜的硬度，满足磨擦剂应具备的基本要求，可以作为磨擦剂在牙膏工业中得到应用。     

利用粉煤灰制备4A分子筛的研究

以粉煤灰为原料,在不外加硅源和铝源的条件下,利用碱熔融-水热法成功的制备得到4A分子筛,并且系统的研究了不同晶化时间与晶化温度对分子筛形成的影响。通过XRD和SEM对获得的产品进行测试,得到该实验条件下合成4A分子筛的最适宜条件为晶化温度110℃晶化时间11 h。     

Programmed cooling crystallization of potassium sulphate solutions

The crystal size distribution from a batch cooling crystallizer is predicted by the numerical solution of a mathematical model which uses empirical kinetics of nucleation and crystal growth. The predictions clearly point out the potential advantages of controlled cooling at a constant nucleation rate for improving the product crystal size over that obtained by either natural or linear cooling.Experimental runs following programmed cooling curves for seeded potassium sulphate solutions showed reasonable agreement with the theoretical predictions. A size dispersion of the crystals was observed which contributes to a slight deviation from theory. Nevertheless, controlled cooling significantly reduced the quantity of nuclei formed and improved the product crystal size distribution.     

Study of the process of stirred ball milling of poorly water soluble organic products using factorial design

The objective of this work was to investigate the mechanism of very fine grinding in a wet ball mill as a function of process parameters, i.e. rotation speed of the mill and grinding medium bead size. The ball mill used was a Dynomill and the grinding medium consisted of zirconium oxide beads. The product is a poorly water-soluble organic compound. Laser diffraction was used to analyze the particle size distribution.During grinding the average particle diameter of the product was reduced to a minimum size, which was constant within the range of tested operating conditions.The grinding parameters were studied to control the grinding process with respect to the required grinding time for reaching the minimum particle size and wear of the set-up.The grinding time was strongly dependent on the grinding medium bead size and on the rotation speed. The grinding process became faster when the rotation speed increased and the grinding medium bead size decreased. The wear of the set-up, and therefore the contamination of the final product with heavy metals, strongly increased with the rotation speed. A similar trend was observed with an increase of grinding medium bead size. The degradation rate of the product was not significant in the range of grinding parameters studied.     

涡流空气分级机工艺参数对窄级别产品粒径分布和产率的影响

在建立涡流空气分级机的窄级别实验系统的基础上,为了研究工艺参数对窄级别产品粒径分布和产率的影响,确定了以两级分级机的转笼转速差和第二级分级机的二次风速为实验因素,以产品的粒径分布曲线为实验指标,对涡流空气分级机的窄级别实验系统进行实验。实验结果表明,随着转速差的减小,产品的粒径分布曲线变窄;随着二次风速的增大,产品中的细粉含量减少,粒径分布曲线变窄。进一步研究了窄级别产品的产率、均匀度和转速差的关系。结果表明,窄级别产品的产率随转速差的减小而降低,均匀度随转速差的减小而增加。发现存在一个最佳转速差?n0,在这个转速差?n0下得到的产品能同时满足物料的均匀度和产率的要求。实验结果对窄级别产品的制备具有一定的指导意义。     

生物质还原-磁选不锈钢酸洗污泥

以生物质为还原剂,通过还原?磁选实验考察了还原温度、生物质种类和添加量、磁场强度及磁选粒度对回收酸洗污泥中铁的影响。结果表明,在反应温度为700℃、棉花秸秆添加量为5wt%、还原产物破碎至粒度小于0.074 mm颗粒占70%、磁场强度为200 mT条件下磁选回收,所得产物中铁品位为67.72wt%、回收率达91.83%。     

Colloidal aspects of precipitation processes

In precipitation processes a chemical reaction produces a sparingly soluble product which starts to precipitate as a solid via nucleation and growth. As a rule, the newly precipitated primary particles are in the nanometer size range. The behaviour of colloidal particles in this size range is governed by interfacial forces. Therefore, in most case the final product particles are secondary particles, which are built by aggregation from the fine primary ones. The final product morphology results from the action of aggregation, rheological behaviour of the suspensions and the shear rates present in the precipitator. Precipitation technology is concerned with the design and operation of such precipitators. In this paper the relevance of fundamental kinetic, collidal and rheological phenomena on precipitation technology are reviewed and discussed.     

轻稀土氟化物纳米微粒的制备及其抗磨性能评价

采用均相沉淀法在醇-水体系中制备了表面修饰轻稀土氟化物的纳米微粒,考察了其摩擦学性能。结果表明,合成产物的微粒粒径为20～30 nm,属于纳米级超微粒子;添加目标产物的润滑油的磨痕直径从0.66 mm降为0.40 mm,抗极压能力显著提高。与共沉淀法相比,均相沉淀法制备的表面修饰稀土氟化物纳米微粒不仅在有机溶剂中具有更为良好的分散性,作为润滑油抗磨添加剂,具有更加优异的减摩、抗磨性能。     

Variation of particle size and its distribution during the synthesis of silicalite-1 nanocrystals

Recent studies imply that the external surface area of the nanozeolite product may, at least in some cases, be related to the average size of the particle population participating in aggregative nucleation, a population which itself is a product of aggregation of even smaller primary nanoparticles. This possibility puts more importance on our understanding of the variation of particle size and its distribution during the crystallization of zeolite nanoparticles. Variation of the particle size and PSD during nanoparticle silicalite-1 crystallization was followed with respect to time by a laser light scattering device with a scattering angle of 173°, for several starting synthesis compositions. Effects of varying TPAOH and water contents in the starting synthesis mixtures on the variation with time of the particle sizes and PSDs, especially across the two distinct aggregation events, were investigated. The products were also analyzed by XRD and AFM. Parallel to the decrease in the average particle size of the final product population with increasing alkalinity and organic template content, its PSD was observed to become narrower too. A reversal in the dependence on TPAOH content, of the average size of the population formed by aggregation, with respect to that of the population participating in aggregation, was observed across both aggregation events, implying that smaller particles aggregated to form larger particles, while larger particles aggregated to form smaller particles during these processes, and this was also seen from the AFM images, to be reflected to the surface features of the final product particles.     

Spray Drying of Aqueous Salbutamol Sulfate Solutions Using the Nano Spray Dryer B-90—The Impact of Process Parameters on Particle Size

In order to prepare spherical salbutamol sulfate particles of adjustable size, a Nano Spray Dryer B-90 was employed. A 3³ full-factorial design was used to investigate the influence of process parameters (mesh size, feed concentration, and drying air temperature) on particle size (median size and width of the particle size distribution), amount of product produced per time, and product yield. The median particle size was significantly influenced by all three factors of the statistical design. Within the design space studied, particle sizes of 1.0 to 6.4 µm were obtained. The width of the particle size distribution (span) increased with increasing mesh sizes. All particles with a particle size greater than 2.4 µm showed a bimodal particle size distribution. Generally, larger mesh sizes as well as higher concentrations led to an increase in the amount of product prepared per time. The corresponding values observed were from 0.4 to 75.8 mg/min. The product yield was independent of the process parameters studied. All products were amorphous after spray drying and were stable up to a relative humidity of 60% at a temperature of 25°C.     

氯化钾间歇冷却结晶生长规律及粒度控制实验研究

采用聚焦光束反射测量技术（FBRM）考察了氯化钾（KCl）间歇冷却结晶过程中晶体成核和生长规律,重点研究了降温速率对KCl水溶液冷却时产生过饱和度的影响,以及添加晶种的相关条件（如晶种粒径和添加量等因素）与KCl晶体产品粒度的关系。同时,采用直接冷却刺激起晶产生“晶种”,并控制其生长达到控制晶体产品粒度的目的。结果表明,在添加晶种条件下,程序降温过程产生的低过饱和度不易引起爆发成核,且晶种的添加量决定着晶体产品的平均粒度与理想生长模型的偏差。另外,降温速率是冷却刺激起晶产生“晶种”粒径的关键因素。     

红土镍矿有价元素高附加值利用的绿色冶金工艺（Ⅰ）熔融碱法提硅制备白炭黑

以红土镍矿为原料,采用碱熔融－碳酸化分解工艺制备出白炭黑产品。研究表明,SiO2的浸出率随反应时间、碱矿比的增加和红土镍矿粒度的减小而增加,随反应温度的升高而先增加后减少。经XRD分析,产品为无定型结构;经FT-IR检测产品为水合二氧化硅;经SEM检测产品颗粒均匀,粒度小于100nm。产品理化性能符合国家化工行业HG/T3065-1999标准。