Melt Spraying / Prilling
Melt Spraying / Prilling: From Solid to Free-Flowing Powder
Prilling, also known as Melt Spraying, is a continuous process of atomizing molten liquids or mixtures and cooling the resulting droplets to create a spherical powder. Suitable materials for processing generally are solids at room temperature, stable in a molten state with relatively low viscosity and have a low melt temperature. A typical material used in this process is wax. Other commonly used terms for prilling are Spray Congealing, Spray Chilling, Melt Atomization and Micronization.
At AVEKA, Prilling and Melt Spraying are differentiated by processing equipment and targeted particle sizes.
For Melt Spraying, the molten material is atomized using a two-fluid nozzle inside a vertical chamber. The atomization air can be heated up to 530°C. The resulting product is a fine, free-flowing powder typically with particle sizes less than 100 microns. The final product is screened directly off of the collection cyclone to remove any large chunks of wax. The material can also be screened to the customer’s desired particle size specification. Any material that is too small or too large can be reprocessed. The final product is packaged into double-lined fiber drums or a container that fits the customer’s needs. Melt Sprayed materials are used in many industries, but a common use is in metal casting industries as a lubrication.
For Prilling, the molten material is atomized using either a single-fluid or two-fluid nozzle system in a nitrogen purged vertical chamber. Typical particle sizes are in the 100 to 1,000 micron range. For most materials, the optimal particle size is 200 to 300 microns. The final product is screened directly off the collection cyclone to remove any large chunks of wax. The material can also be screened to the customer’s desired particles size specification. Any material that is too small or too large can be reprocessed. The final product is packaged into double-lined fiber drums, heat-seal bags or super sacks. Processing rates may vary depending on targeted particle size and materials, but the system is capable of producing ~500 kg per hour. Materials processed on the Prilling system are done so at a Food Grade, Kosher and Organic certified facility. Common material processed are phytosterols or various waxes.
AVEKA’s full-service analytical laboratory allows for rapid process adjustments during trials and excellent quality control for production operations. For example, melt sprayed products can be characterized by imaging particle morphology and measuring particle size distribution. Additionally, extensive pre- and post-processing capabilities contribute to the turnkey experience AVEKA provides.