Powder Bulk Handling Why Particle Characterisation is Key for Challenges like Urban Mining
Challenges for Bulk Solids Technology – Roughly 50 per cent or more of substances used in the chemical industry are solids which need to be processed, handled and transported. A learning curve is associated with the handling of powder and granulates. Read on for a gist of the characteristics and norms that are required to be looked at to make bulk handling processes efficient.
Bulk solids are found in all sectors of the industry including food, cosmetics, chemicals, automobile production, biomass processing and waste management. Particles with special property profiles are often the secret to success in new product development. Composite materials, fuel cells and catalysts are a few examples. In addition, special surface properties, particle size and particle distribution can be manipulated to create new active ingredients for cosmetics and pharmaceuticals.
The basic principles behind many bulk solids processing techniques including screening, mixing and comminution have not changed for the past hundred years. That does not mean, however, that no further innovation is possible. Bulk solid property profiles are becoming increasingly complex and the quality standards are more and more demanding. Particle size, for example, continues to decrease. 20 years ago the micrometer range tended to be the norm but nanotechnology has now become mainstream. This has created the need for finer distributions.
Bulk Solids – a Challenge for Equipment Operators
The properties of fluids are now well understood, but surprising things can happen during handling of powder, dust and granulate. This is something which equipment and plant operators are well aware of.
What makes bulk solids handling so difficult? There are products that constantly exhibit different behavior in identical filling trials or, even worse, stagnant zones form in the fourth trial (but not before), negating all of the previous results. Upstream handling of bulk solids can also have an influence. Particle compaction during conveying and filling is a factor that may need to be considered.
The Ideal Particle – Does it Exist at All?
The ideal particle rarely exists. In most cases, minor variations in size and surface characteristics make it difficult to accurately predict filling and dosing behavior. However, knowledge about properties such as bulk solid density, particle size, particle shape, moisture, etc., make things easier. Precise characterization of the flow properties is also important.