Affinity

In powder technology, affinity refers to the tendency of powder particles to interact with other substances such as liquids or gases. This property influences processes such as wetting, agglomeration and flowability of powders.

Wetting of powder particles: The affinity between powder particles and liquids determines how effectively a liquid can penetrate into the interior of the particles. Hydrophilic powders have a high affinity for water and are easier to wet, while hydrophobic powders have a lower affinity and are more difficult to wet. The capillarity of the powder and the surface tension of the liquid are crucial. A high affinity leads to spontaneous wetting. This is desirable for powdered instant beverages.

Agglomeration: The affinity between particles can lead to the formation of agglomerates. In industrial processes, agglomeration is used to produce powders that are free-flowing and low-dust.

Flow aids: To improve the flow properties of powders, flow aids are sometimes used. These coat the moist powder particles and reduce the interparticular forces. A high affinity between the flow aid and liquid can cause the liquid to be absorbed, thereby separating the particles from each other and improving the flowability of the powder.

Mixing processes: Various side effects can occur during mixing. These include processes such as deagglomeration, spheronisation, crushing, wetting, coating, segregation and agglomeration. These processes can be controlled using amixon® mixers.