Agglomeration in Particle Engineering
Posted by Pat Moran on Dec 6, 2016
Agglomeration is a critical tool from a particle engineering and design standpoint, which allows IFP to manipulate particle size and shape and exert some control over end product functionality when engaging in fluid-bed technnologies. Some reasons for agglomeration include improvement or modification of: powder flow, wetting, dispersibility, water-solubility, bulk density, dustiness, and compositional uniformity.
Agglomeration is the process of binding particles together in order to form larger aggregates. The process consists of three basic stages: wetting and nucleation, consolidation and growth, and attrition and breakdown . The three basic stages are laid out sequentially below, but it is important to note that they are all interrelated and occurring in unison.
Wetting and nucleation
At this stage, liquid droplets are introduced to the powder. The droplets collide with and wet across solid particle surfaces. Capillary and viscous forces within the liquid allow it to bind multiple solid particles together into a “loose” fluid aggregate (or nuclei). Chemical composition of the solid and liquid as well as their physical morphology and collision velocity (energy) will determine how the nuclei forms and proceeds through the consolidation and growth stage.
Consolidation and growth
During this stage, water evaporates from the liquid phase of the nuclei, while viscous and capillary forces increase to more strongly bind the solid particles. Simultaneously, solid particle surfaces may begin dissolving into the liquid phase further increasing its viscosity. At this time, the increased binding capacity of the liquid phase may facilitate growth of even larger aggregates as there is potential for multiple nuclei to collide and stick together.
Attrition and breakdown
During this stage, the water has largely evaporated yielding a solid aggregate. This solid structure has a specific shape and material properties. The structure will resist breakdown to some extent, and its durability may be characterized by material parameters such as hardness, friability and tensile strength. During the process a collision between two solid particles will transfer a certain amount of energy (based on the mass, velocity and geometry of the collision). If the energy present exceeds thresholds of certain material parameters then the aggregate will fracture to dissipate the excess energy.
Successful particle engineering requires careful monitoring and exploration of the processing parameters, as well as their impact upon the evolution of the in-process powder product (characterized via repeated sampling and analyses). This approach informs us on the “path” we trace through the three stages outlined above, and on how decisions on process settings effect this pathway. Each new product design endeavor is a learning experience fueled by data as the experimental design space is expanded and refined through continued testing. The ultimate goal is to design a process that produces the most functional product, as efficiently and consistently as possible.
IFP’s current particle engineering technologies include: fluid bed agglomeration, coating, encapsulation, blending, milling, and classifying.
We enhance functionality through
- Improved dissolution or solubility
- Dust-free processing & reduced dust formation
- Flowability improvement (free flowing)
- Homogeneity & stability against segregation
- Improved dose uniformity
- Increasing bulk density
- Protecting active substances from moisture, oxidation (encapsulation)
- Controlling release of active substances
- Enhancing shelf life
- Smell and taste masking
- Stabilization of mixtures
- Reducing hygroscopicity
 S.M. Iveson et al., Powder Technology 117 (2001) 3-39, Nucleation, growth and breakage phenomena in agitated wet granulation processes: a review
- Agglomeration in Particle Engineering
Agglomeration is a critical tool from a particle engineering and design standpoint, which allows us to manipulate particle size and shape and exert some control over end product functionality. Some reasons for agglomeration include improvement or modification of: powder flow, wetting, dispersibility, water-solubility, bulk density, dustiness, compositional uniformity.
IFP's contract batch fluid bed agglomeration instantizes,improves food and beverage powder dispersion, achieves precise dosing, and reduces product dusting to create precise composition.