Continuous Agglomeration Process and Technology

Produce controlled porous agglomerates by combining mixing, liquid addition and drying in a continuous process. Continuous agglomeration is applied where consistent particle size enlargement and stable powder behaviour are required at industrial scale.

In these processes, powder characteristics are not only defined by the agglomeration step itself, but by the interaction between dosing, wetting, mixing intensity and downstream drying. Hosokawa Micron integrates these unit operations into a continuous agglomeration system based on the Flexomix agglomerator and fluid bed drying technology.

From Fine Powders to Functional Agglomerates

Agglomeration is typically applied when fine powders no longer meet process or product requirements. Cohesive behaviour, dust formation or poor wettability can limit both handling and end-use performance.

In continuous agglomeration, these limitations are addressed by introducing a controlled liquid phase into the powder. This creates liquid bridges between particles, initiating agglomerate formation. The structure is subsequently stabilised during drying, resulting in a defined particle size distribution and a porous internal structure.

The resulting agglomerates retain the primary particle characteristics, while introducing new bulk behaviour such as improved flowability, controlled density and enhanced dispersibility.

Agglomeration Mechanism in the Flexomix

At the core of the Hosokawa Micron system is the Flexomix agglomerator, originally developed by Schugi and now part of the Hosokawa Group.

Agglomeration takes place under high-intensity mixing conditions. A central rotor equipped with adjustable mixing elements rotates at high speed, typically between 1000 and 5000 rpm. This generates a centrifugal force that accelerates the powder towards the flexible wall of the mixing chamber.

Liquid binders are injected directly into this turbulent zone. Due to the combination of high shear and uniform liquid distribution, agglomeration occurs almost instantaneously. In practice, wet agglomerates are formed within seconds and discharged continuously from the system.

This short residence time limits thermal exposure and prevents unwanted changes to the material properties.

Controlling Agglomerate Structure

The structure of the agglomerates is defined by the interaction between liquid addition, mixing intensity and residence time.

In the Flexomix process, this results in open, porous agglomerates with a characteristic raspberry-like morphology. This structure provides a relatively large specific surface area, which directly influences how the powder behaves during reconstitution.

For applications such as instant food powders or pharmaceutical excipients, this translates into improved liquid penetration, faster dissolution and more predictable dispersibility.

At the same time, process parameters can be adjusted to influence bulk density and particle strength, depending on downstream requirements.

Drying and Stabilisation in Fluid Bed Technology

Immediately after agglomeration, the wet product is transferred to a fluid bed dryer and cooler by Hosokawa Micron. Here, the agglomerates are dried and stabilised under controlled airflow and temperature conditions.

Drying is not only required to remove moisture. It also determines the final mechanical strength of the agglomerates and their resistance to breakage during handling and transport.

The combination of fluidisation and controlled air distribution ensures uniform drying across the product bed, which is essential for maintaining a narrow particle size distribution and consistent product quality.

Particle Size Control Through Classification

Following drying, the product is classified into defined fractions. On-size material is separated from fines and oversize particles, enabling precise control over the final particle size distribution.

Oversize particles can be reduced and recycled, while fines may be reintroduced into the agglomeration process. This closed-loop approach stabilises the process and improves overall yield.

As a result, continuous agglomeration systems are capable of producing agglomerates typically in the range of 100 to 1,500 microns, depending on product requirements.

Process Stability and Control

Consistent agglomeration requires careful control of multiple process variables. The ratio between liquid and powder, the mixing intensity and the drying conditions must be balanced to avoid over-wetting or insufficient bonding.

In industrial systems, these parameters are managed through integrated control systems that ensure stable operation under varying conditions. This allows the process to maintain consistent product quality even when raw material properties fluctuate.

Continuous Operation at Industrial Scale

One of the defining characteristics of the Hosokawa Micron agglomeration approach is continuous operation. Unlike batch processes, continuous agglomeration enables a steady-state process with predictable product quality and high throughput.

Depending on the system configuration and material characteristics, capacities can range from approximately 100 kg/h up to 40,000 kg/h.

This makes the technology suitable for large-scale production environments where reproducibility and efficiency are critical.

From Process Understanding to System Design

Successful agglomeration depends on more than equipment selection alone. It requires a detailed understanding of how material properties interact with process conditions.

For this reason, Hosokawa Micron supports process development through laboratory and pilot-scale testing, allowing process parameters to be validated before full-scale implementation. This ensures reliable scale-up and reduces technical risk during industrialisation.