Toll Processing Basics: Top 11 Particle Technology Terms

Customers often approach us with a vision for a product, not just a toll processing order. They may struggle to achieve a certain particle characteristic, whether in a precision-milled food ingredient for incorporation into a recipe, or in a specialty-compounded proprietary polymer or pharmaceutical ingredient. With our in-house testing capabilities we can validate, adjust, and enhance our particle technology processes to meet exacting specifications — and that enables our customers to innovate in their markets.

But equipment and dedicated facilities aren’t all it takes to achieve a customer’s vision. The force behind our particle technologies is the know-how of our problem-solving experts. To get a sense of the sheer range of toll processing capabilities we can put to work for you, we think you’ll find it helpful to review a few important terms related to particle characteristics, processing methods, and controls.

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8 Basic Particle Technology Terms to Get Started

Blending: The process of gently combining multiple components. The three methods of blending include convection, diffusion, and shear.

Cryogenic Mill: An industrial machine that uses liquid nitrogen to lower the temperature of a material to be milled. Milling polymers is difficult without cryogenic milling, because polymers would otherwise melt in a mill’s high-energy, high-temperature environment. Also called cryo-milling.

Fluid Bed Drying: A method for the controlled and gentle drying of wet solids. The process subjects solid particles to conditions that cause them to behave like a fluid. Hot air at high pressure is sent through a perforated bed of wet solids that are lifted and suspended in the airstream (this is the fluidized state). Vaporized liquid is carried away by the drying gas. Fluid bed provides uniform drying conditions compared to uneven drying in trays.

Friability: A material’s tendency to fracture during normal handling.

GHS Compliant: Globally Harmonized System (GHS) of the Classification and Labelling of Chemicals is a set of recommendations to ensure the safe production, handling, transport, use, and disposal of hazardous materials. This collection of best practices, developed by the United Nations, was adopted in 2012 by OSHA, a revision of the Hazard Communication Standard to align with the GHS. OSHA calls this revision “HazCom 2012.”

Safety Data Sheet (SDS): Once known as an MSDS, this document includes information and guidance for handling a material, usually a chemical. Typical topics covered: any physical, health, and/or environmental hazards; any protective measures needed including personal protective equipment (PPE); and any safety precautions for handling, storing, and transporting the material, including first aid and clean up procedures.

Twin-Screw Extrusion: A type of plastic extrusion during which two or more ingredients are mixed or compounded. This is an extremely energy-efficient process with a wide range of applications and great flexibility of the processing system. This extruder provides maximum performance on the smallest product quantities and is scalable for full-scale production. Feeding systems enable different ingredients to be added to the mixture at the correct process interval, and multiple heating zones customize complex applications. Also see “compounding.”

Wet Media Milling: A milling method during which particles are dispersed in a liquid slurry and media milled to obtain a uniform particle size distribution. The grinding media may be beads or balls made of plastic, glass, ceramics, or steel. The shearing forces (tearing), impacting (crushing), and attrition (tearing and crushing each other apart) create particle distributions in the nanometer or sub-micron ranges. The particles are simultaneously dispersed in the liquid, which is ready for use or can be dried and separated for use in other products. With the proper milling equipment, toll processors can cost-effectively create uniformly fine particles with limited or no contamination. Also called wet milling.

Extra Credit: 3 Terms Related to Explosive Materials

Combustible Dust: Any fine material that has the ability to catch fire/explode when mixed with air. Combustible dusts can come from solid organic materials (flour, grain, wood, etc.), metals (aluminum, titanium, etc.), and nonmetallic inorganic materials (fiberglass, carbon, etc.). Combustible dusts are ranked into one of four classes; St0, St1, St2, and St3. The level of explosion violence increases with the class number.

Pmax: Measures the maximum explosion overpressure generated in the test chamber.

KSt: Measures the normalized rate of pressure rise of a combustible dust.

The More You Know…

One thing any of our particle science and engineering experts will tell you is this: There’s always more to learn. That’s one reason our problem-solving teams don’t shy away from big toll processing challenges. The most inspiring product challenges, together with our particle technology expertise, lead to the innovative breakthroughs that can change entire markets. 

Want to learn more about the details of toll processing? Our glossary is a great resource to get started. Get yours by clicking the link below!