News on how Freeze Granulation can improve our powder properties

Nano ice formation in granules

Nano ice in granules by Freeze Granulation

Nano ice formation in granules by Freeze Granulation process is a key factor for the unique homogeneity of particles and binders achieved in the resulting granules. This is especially important for nanopowders, fine particles and binders where migration of these could occur during conventional drying, like spray drying.

Please contact us and we will further discuss the opportunities with Freeze Granulation on your powder system and read more on technology and we propose a Granulation Test of your powder system.

Granule with nano-ice and nanopowder — Nano-ice formation in granules of nanoparticles

LED photoluminescence granulation

LED photoluminescence granulation

Freeze Granulation is today used for commercial production of homogeneous granules for the production of oxides used as a ceramic phosphor plate for white illumination in LED Lighting. By using Freeze Granulation of the powder and binder mixture, compared with spray drying, it is possible to manufacture a homogeneous phosphor plate with optimal properties for to generate a soft and warm white light from high power LEDs.

Ultrasonic atomisation

Freeze Granulation with ultrasonic atomisation of droplets

Freeze Granulation can be made using ultrasonic atomisation of spherical droplets. The resulting granules have a narrow granule size distribution and the granule size is in general smaller (average 120 micron) compared to a regular spray nozzle. The granulation speed is also slow with about 0.3 to 0.5 litre/h.

Ultrasonic automisation — Ultrasonic atomisation

Transparent and translucent ceramics

Transparent and translucent ceramics by Freeze Granulation

Freeze Granulation is today being used for commercial manufacturing of transparent and translucent ceramics. The main advantage is to achieve a homogeneous distribution of the starting material which will result in rapid reaction and sintering at low temperature where grain growth of the material will be avoided.

POWTECH 2013 – Nürnberg

POWTECH 2013 – Nürnberg. Good and interesting meetings on powder processing and how Freeze Granulation can improve the homogeneity of the granules, for example nanomaterial like CNT – Carbon Nano Tubes.

POWTECH 2013 – Nürnberg

Preparation of PIM or Extrusion Feedstock

Freeze Granulation of PIM or Extrusion Feedstock

Powder injection molding (PIM) and extrusion are powder shaping techniques that typically involve preparation of high viscous feedstock making it difficult to achieve full homogeneity. Especially if the powders are fine (submicron or nano) and/or if it is a composite material. By doing an initial preparation of a low viscous (based on water or organic) suspension the powders can be properly de-agglomerated, dispersed and homogenized. Other constituents aimed for the PIM or extrusion process can be added prior to freeze granulation. The result will be a homogenized, soft and dust free powder, easy to mix and disperse into a feedstock for PIM or extrusion at high powder concentration and homogeneity, promoting sintering and ultimate material performance.

Preparation of PIM or Extrusion Feedstock

Frysgranulering för tillverkning av homogena granuler

PowderPro har i samarbete med Swerea IVF (då Svenska Keraminstitutet) under 1980-talet vidareutvecklat en alternativ granuleringsteknik – frysgranulering (Freeze Granulation) – vilken möjliggör konservering av homogeniteten från suspension till torrt granulat. Genom att spreja en pulversuspension ner i flytande kväve sker en momentan frysning av dropparna (granulerna). I den efterföljande frystorkningen sublimeras isen utan risk för segregeringseffekter som lätt sker vid konventionell torkning i luft. Resultatet blir sfäriska och friflytande granuler med optimal homogenitet lämpliga för t ex pressning av keramiska komponenter.

Frysgranulering: Homogena pulvergranuler med överlägsen prestanda

Freeze Granulation produce flowable and crushable (soft) granules

Freeze Granulation produce flowable and crushable (soft) granules suitable for die pressing applications. Spray drying yield flowable, but hard granules which are difficult to cruch during die pressing.

Freeze Granulation vs Spray Drying advantages — Freeze Granulation vs Spray Drying

Can you make spherical granules?

Yes, with Freeze Granulation it’s possible to make spherical, homogeneous and dust-free granules with optimal flowability which is critical for automatic uniaxial pressing of for ex ceramics and metal powders.

You can expect spherical and homogenous granules of powders in terms of distribution of particle size and other possible additives you want to use. The granules with a size distribution in the range of 50-300 microns will have weak inter particle bonding making them easy to break down in pressing or re-disperse into another formulation. Very much depend upon how you intend to process the powder and depending on that, adaptation can be made. If you tell us more we can further discuss the opportunities.

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Spherical granules made by Freeze Granulation

Homogeneity preservation from suspension to dry granule

If you are looking for optimal homogeneity in your granulated material, then you should evaluate our unique granulation technology – Freeze Granulation!

Today, Freeze Granulation is the only granulation technology that will preserve the homogeneity from suspension to dry granule, which is crucial for good results in most processes.

Spray cooling or rather called spray freezing is the first step in the freeze granulation process where a suspension is atomized, sprayed with a nozzle, into a chamber with liquid nitrogen. The small droplets are then rapidly frozen with a minimum of ice crystal growth. The frozen material (granules) are then transferred to a freeze dryer where the ice is removed by sublimation, i e never go through a liquid state that ensure homogeneity preservation.

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