Agglomeration of instant products

Although Hosokawa Micron is well known for its mixing and drying systems, it actually has much more technology to offer for making custom-made powders. The company designs and manufactures complete processing lines that enable customers to manufacture end products with specific characteristics – including agglomerated instant products.

Hosokawa Micron is known around the world for its broad portfolio of solutions, and especially for its milling, mixing and drying systems. These systems have earned their stripes over the past decades in numerous applications in every conceivable market. The company has a wealth of experience in the processing of a very wide range of raw materials. This has resulted in a strategy of product diversification, with the company developing technologies for new applications. The current range of solutions facilitates the design of complete production lines that enable customers to directly give their end products the desired characteristics. This is done by subjecting the raw materials and products to mechanical, physical and/or chemical treatments.

Areas of expertise

The Hosokawa Group has 1,600 employees, production facilities plus various Centres of Competence in five countries, ten R&D and test centres, a network of experienced representatives, and service centres in all industrialized nations. The individual facilities work closely with one another at all levels. Hosokawa Alpine AG in Augsburg (Germany) takes care of the milling and classification activities, and a separate German facility called Alpine Compaction, based in Leingarten, is specialized in compaction to produce pellets, briquettes or powders with better flow properties. In addition to having long-standing expertise in mixing and drying, Hosokawa Micron B.V. in Doetinchem also has many decades of experience in (instant) agglomeration as a method of increasing the particle size of powders to form easily soluble granules.

Properties of instant products

Powders that are intended for specific applications can be agglomerated to improve certain properties. A prime example is the use of this technique to improve the characteristics of instant products, and in particular the solubility of the powder in a liquid (e.g. for the preparation of instant beverages). Agglomeration can also be used to improve the powdered product's flow properties and reduce dust. A dust-free, non-dispersible product reduces the health and safety risks and prevents technical problems arising in production processes. Good flow properties are very important for the dosing of instant products in drinks vending machines. Furthermore, material with good flowability is easier to handle in production processes, easier to transport and easier to unload from silos.

Close-up of agglomerated gravy powder

Separation

Another major reason to agglomerate products is to prevent separation after mixing. This maintains the quality of the product mixture until it reaches the end user. Thanks to a uniform and homogeneous product, it is also possible to guarantee a consistent bulk density, which is necessary to ensure that the packaging units are filled with precisely the desired volume each time. Agglomeration results in a better product quality that is appreciated by end users and consumers alike.

Granulation techniques

Once the desired characteristics, properties and composition of the granulate have been determined, the next step is to identify the optimal production process. A variety of granulation technologies are available, including for example granulators, pellet presses, extruders, spray dryers and the Hosokawa Flexomix. These methods vary in terms of the particle size range, the particle shape and other product properties they can achieve. When good instant properties are required, the Hosokawa Flexomix is a very popular choice. Another advantage of this system is that it produces dust-free granules with excellent flowability.

Hosokawa Flexomix

The Hosokawa Flexomix is a compact system for the continuous mixing and agglomeration of powders. It produces particles with a raspberry-shaped structure, typically with a particle size of 0.2 to 1.2 mm. Depending on the application, the capacity can vary from 50 to 25,000 kg/hour. A dosing feeder ensures that the system is fed with a controlled supply of powders and liquids. Liquids and powders undergo intensive mixing in the Hosokawa Flexomix, causing particles to adhere to one another to form granules. The granule size is determined by the ratio of powders to liquids and the process conditions. In most cases the granules pass into a fluid bed dryer and cooler, after which they are sieved and then packaged. Hosokawa Micron also takes care of the de-dusting and control of the entire process.

Flexomix agglomeration system @ Test centre Hosokawa Micron B.V.

Self-cleaning

The Hosokawa Flexomix comprises a vertical rotor with mixing elements rotating at high speed in a flexible mixing chamber. To prevent product build-up inside the mixing chamber, the flexible wall is constantly massaged from the outside. This ensures that the mixing chamber is kept clean – a prerequisite for process stability and a consistently high product quality. The fill rate of the mixing chamber is just a few percent, and the product remains inside it for between 0.2 and max. 1 second. The rotor, mixing elements and flexible chamber can be made of various materials, depending on the specific application. The quantity and positioning of the mixing elements is also aligned with the relevant application.

The Hosokawa Flexomix is unique due to the fact that it enables several different powders and liquids to be processed in a single step. The energy consumption can be precisely controlled by regulating the rotor speed and is minimized thanks to the short mixing time. The system offers easy access for inspection and cleaning purposes.

Test centre

Hosokawa Micron has a test centre in Doetinchem that provides access to various types of batch mixers and dryers ranging from 1 litre to 6,000 litres in capacity as well as to various types of direct and indirect drying systems. There is also a complete agglomeration pilot plant. Besides a Schugi Flexomix, this comprises liquid dosing stations, powder feeders and a fluid bed dryer and cooler. Furthermore, the Hosokawa Group can supply solutions for milling and compaction processes. In conjunction with the theoretical knowledge and practical expertise of its process technologists, Hosokawa Micron can develop effective solutions for all applications.

Mattijs Raadsen, Hosokawa Micron B.V.