The first step is to load the containers in a way to minimise segregation taking place during the deposition of the powder. The best way to accomplish this will depend on the geometry of the container and the way in which the flow stream is presented to the equipment. Some of the most aggressive segregating mechanisms are developed in surface repose condition during the formation of a growing pile therefore means to diffuse the fill stream to form a more level disposition of the loading process will go far to reduce this source of segregation.

Firm packing to retrain percolation is effective. Better done by compression, such as vertical pressure, than by vibration and best done quickly if practical. Vacuum packing is very effective at inhibiting particle movement in bulk container. If the contents are in a plastic liner that can be subjected to a small negative pressure it will hold the mass to a coherent structure under most rough handling conditions.

The final aspect is unloading the container without allowing segregation to take place. Rapid dumping usually inhibits the separation of fractions. Overall, ways to mitigate and re-homogenise segregated powders are relatively straightforward when the basic principles are understood. I suggest reading the ‘User Guide to Segregation’, published by The British Materials Handling Board, for a review of the background and some useful techniques. Copies are available from www.ajax.co.uk ■