Over 70% of materials in the food, chemical and pharmaceutical industries (from raw materials, additives and intermediates through to manufactured products) are supplied as relatively free-flowing powders, intended to be suitable for the manufacturing process or final application. For logistical reasons however, these materials will often have to be stored for extended periods during which time some powders have the potential to gain strength due to prolonged and undisturbed particle/particle interactions. This is generally referred to as ‘caking’ and can significantly limit the ability of a powder to pass through the process train without interruption as well as detrimentally impacting product quality.
This paper will present case studies which evaluate the flow properties of different powder systems that are affected by chemical, moisture and temperature based caking mechanisms. It will show how the propensity to cake can be effectively quantified with respect to the powders’ flow properties and how this can assist with understanding and adapting the processing environment to retain optimal processability.