Development of a semi-continuous centrifugal process for classifying colloidal particles

开发用于分级胶体颗粒的半连续离心工艺

基本信息

批准号：
222168573
负责人：
Professor Dr.-Ing. Hermann Nirschl
金额：
--
依托单位：
Arbeitsgruppe Verfahrenstechnische Maschinen (VM)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2012
资助国家：
德国
起止时间：
2011-12-31 至 2015-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/222168573?language=en
关键词：
Development semi continuous centrifugal process

项目摘要

Within the last years further progress was made in development of novel materials based on submicron particles. However, obtaining the commonly required narrow particle size distribution is a problem for most processes. With a view to production in pilot or industrial scale, particle size distributions of the synthesized colloids are often too broad to be used in cutting edge technology such as printable electronics, polishing media for semiconductors (CMP slurries) and composite particles used for cancer treatment. For this reason narrow fractions must be separated from the primarily broad distributions in subsequent steps. The term for this process is classification. Classification is either achieved by removing the fine or the coarse fraction.A continuous or semi-continuous classification of particles by centrifugation in pilot scale shows certain limitations concerning particle size and difference in density of the particles and the surrounding liquid of the suspension. Those separation processes depend on particle sizes larger than 1 µm and density differences between solid and liquid of at least a factor of two. The classification of submicron particles is so far limited to the laboratory scale. In pilot and industrial scale, deep bed filters that are low in selectivity are used to remove the coarse fraction in CPM slurries. An optimization of deep bed filtration process is not possible, because the determining physics impede an increase of selectivity. Thus, the aim of the applied project is the investigation of classification in the nanometre scale using a tubular bowl centrifuge.With a density difference between solid and the surrounding liquid of 100 kg/m³ a cut size of 100 nm is aspired. For higher differences in density between particles and liquid a cut size of 20 nm seems achievable. By using carbon fibre rotor and active magnetic bearings, the tubular bowl centrifuge generates up to 160000 G for classification of colloidal particles. The centrifuge is built in a current research project and needs to be modified for the intended application. The results of the investigations will describe the sedimentation behaviour of various particle systems in dependence of particle properties and process parameters.A further work package is the characterization of the flow pattern by Laser Doppler Anemometry in a centrifuge. This technique had been employed for measuring the flow pattern in a tubular bowl centrifuge. The results have been published recently. The gained knowledge of the flow characteristics will be used to optimize the inlet geometry. Further measurements are necessary to understand the particle and flow channelling close to the feeding system in the centrifuge. This is highly important to achieve the intended cut size.Furthermore the experimentally determined flow pattern enables the validation of the model calculations which will be carried out within the applied project.

在过去的几年中，基于亚微米颗粒的新型材料的发展取得了进一步的进步。但是，对于大多数过程，获得通常的窄粒径分布是一个问题。考虑到以试点或工业规模的生产，合成的胶体的粒度分布通常太宽，无法用于尖端技术，例如可打印的电子设备，用于半导体的抛光介质（CMP浆液）（CMP浆液）和用于癌症治疗的复合颗粒。因此，必须在随后的步骤中将狭窄的部分与主要的广泛分布分开。此过程的术语是分类。分类是通过去除罚款或粗糙的分数来实现的。通过以试验量表离心对粒子进行连续或半连续分类，显示出有关粒径和颗粒密度和悬浮液的周围液体密度差异的某些局限性。这些分离过程取决于大于1 µm的粒径以及固体和液体之间的密度差异至少为两个因子。迄今为止，亚微米颗粒的分类仅限于实验室量表。在飞行员和工业尺度上，选择性低的深床过滤器用于去除CPM浆中的粗糙分数。不可能优化深床过滤过程，因为确定物理学会阻碍选择性的提高。这是应用项目的目的是使用管状碗离心机在纳米尺度上进行分类的投资。与固体与周围液体之间的密度差为100 kg/m³，切割大小为100 nm。对于颗粒和液体之间的密度较高的差异，切割大小为20 nm似乎是成功的。通过使用碳纤维转子和主动磁轴承，管状碗离心机可产生多达160,000 g的胶体颗粒分类。离心机是在当前的研究项目中构建的，需要为预期的应用进行修改。调查的结果将描述各种粒子系统在粒子特性和过程参数依赖性的沉积行为。进一步的工作包是离心机中激光多普勒动态测定法对流动模式的表征。该技术已用于测量管状碗离心机中的流动模式。结果最近发布了。获得的流量特征的知识将用于优化入口几何形状。需要进一步的测量，以了解离心机中进食系统附近的粒子和流动通道。这对于实现预期的切割大小非常重要。Furthermore实验确定的流动模式可以验证模型计算，该计算将在应用项目中进行。