Understanding and measuring powder flowability
Knowing the flowability of powders helps you optimize a product, control its quality, and ensure reliable production. Understanding flow behavior is also important in designing silos and process equipment that prevent arches and irregular flow. This article defines flowability, describes how to measure it using a ring shear tester, and gives examples from industry.
When talking about the flowability of powders, it’s important to define first what flowability really means. People who handle fine and easy-to-fluidize powders, such as cement and coal dust, often say that their powder’s flowability is good because it “flows like water.” The same powders, however, sometimes flow poorly and create stagnant zones or arches in storage vessels. That’s why, to be meaningful, the definition of flowability must account for powder behavior in true-to-life situations, such as when flow is problematic.