sonochemical enhanced micro bubble flotation

声化学强化微泡浮选

• 批准号: 382121754
• 负责人: Professor Dr.-Ing. Urs Peuker
• 金额: --
• 依托单位: Institut für Mechanische Verfahrenstechnik und Aufbereitungstechnik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/382121754?language=en
• 关键词: sonochemical; enhanced; micro; bubble; flotation

The development of fractionation processes for fine particle systems is the focus of the priority program 2045. Those processes are supposed to respect more than one property for the separation. The established separation process column flotation is modified through the use of micro-bubbles and the application of ultrasound with the aim to shift the application window to the size range of 100 nm - 10 µm. The two modifications do not act independently, they have a potential for synergies. Since the resonance frequency of the microbubbles fits to the frequency band of technical ultrasound, the ultrasound is supposed to create intense oscillations of the bubbles in this concept. The oscillation of the bubbles leads to an increased contact probability with the particles. The contact probability is further enhanced due to the fact that the inertia forces of the microbubbles are reduced, which leads to a higher relative mobility. Since the buoyancy decreases with the bubble size, the rising velocity as well as the transport capacity of the microbubbles decreases, too. Furthermore the effort to generate high concentrations of microbubbles is high. Therefore a hybrid approach is chosen, which is the application of a bi-modal bubble size distribution. A defined concentration of micro bubbles is mixed with the conventional bubble size of column flotation. The research work focuses on the selective coupling of particles to the (micro-)bubble system and the stability of the microbubbles regarding coalescence. An Atomic-Force-Microscope is used with a particle or a bubble as probe (CP-AFM). It determines the interaction force, especially the potential boundary at the contact between particle and bubble as well as between bubble and bubble. Since this process is a function of the physico-chemistry, the flotation chemistry has to be optimized. The CP-AFM-measurements are also conducted with superimposed high frequent oscillations, which allows in the AFM to simulate the microscopic behavior due to ultrasound. The engineering approach uses a flotation column in the mini-plant-scale, which is modified for the application of both ultrasound and microbubbles. The production of the microbubbles uses a rotating membrane device. The influence of the flotation chemistry on bubble formation is quantified, too. The experiments in the mini-plant focus on the determination of the multi-dimensional separation curve (size / material composition) as well as on the impact of the bi-odal bubble size distribution on the structure, stability and separation properties of the froth. The particle system for the bench mark experiments is a mixture of functional materials, which is carbon black/graphite and a metal-oxide. This challenge derives from the specifications of the mechanical recycling of electrode materials from batteries. In the second period the focus is on the collection of technological process data and the morphological separation.

细颗粒系统分馏工艺的开发是优先计划2045的重点。这些过程应该尊重不止一个分离属性。通过使用微气泡和应用超声波对已建立的分离工艺柱浮选进行了修改，目的是将应用窗口转移到100 nm - 10 µm的尺寸范围。这两种修饰并不是独立作用的，它们有协同作用的潜力。由于微泡的共振频率适合于技术超声的频带，因此在该概念中，超声应该产生气泡的强烈振荡。气泡的振荡导致与颗粒的接触概率增加。由于微泡的惯性力减小，接触概率进一步增强，这导致更高的相对迁移率。由于微气泡的浮力随气泡尺寸的减小而减小，因此微气泡的上升速度和输运能力也随之减小。此外，产生高浓度微泡的努力是高的。因此，选择了一种混合方法，即应用双模态气泡尺寸分布。将规定浓度的微气泡与柱浮选的常规气泡尺寸混合。研究工作的重点是选择性耦合的颗粒（微）气泡系统和稳定性的微气泡有关的合并。原子力显微镜使用粒子或气泡作为探针（CP-AFM）。它决定了相互作用力，特别是粒子与气泡以及气泡与气泡接触处的势边界。由于该过程是物理化学的函数，因此必须优化浮选化学。CP-AFM测量还使用叠加的高频振荡进行，这使得AFM能够模拟由于超声引起的微观行为。该工程方法在小型工厂规模中使用浮选柱，该浮选柱针对超声和微泡的应用进行了修改。微泡的产生使用旋转膜装置。浮选化学对气泡形成的影响也被量化。在小型装置中的实验集中于多维分离曲线（尺寸/材料组成）的确定以及双峰气泡尺寸分布对泡沫的结构、稳定性和分离特性的影响。用于基准实验的颗粒系统是功能材料的混合物，其是炭黑/石墨和金属氧化物。这一挑战来自电池电极材料的机械回收规格。在第二阶段，重点是收集工艺过程数据和形态分离。