7 Reasons Particle Size Analysis is Essential

15 Feb, 2012

An examination of the various industries that use particle size analysis during the manufacturing or production stage reveals that the process is used for a similar reason: quite simply, to control the amount of chemical reactions that occur when the product is being used. In this article, we’ll take a look at seven of the most crucial properties that are affected by particle size in various manufacturing scenarios.

1. Rate of reactions

When it comes to solids, the surface area of the particle is critical in determining the rate of chemical reaction. Chemical reactions are far more likely to occur in fine particles than otherwise. A great example of an industry reliant on this principle is the cement industry, which must deliver the appropriate reaction rate in order to achieve the desired product.

2. Potential to dissolve

The effect of particle size on dissolution rate is similar to the influence of particle size on the reaction rate. By creating finer particles and therefore increasing surface area, the physical barriers to dissolution are weakened, making the process occur much more quickly. Put simply, finer particles are more likely to dissolve quicker. The pharmaceutical industry knows the importance of this, as the speed of dissolution has direct effects on bioavailability and, therefore, the effectiveness of any given drug.

3. Packing density

The efficiency with which particles pack together is crucial to many industries as well. As a rule, large particles are going to pack more poorly than small particles. By decreasing the particle size, packing density is improved and voidage (unoccupied volume) is reduced. This is particularly important in production of metals through mould filling, as unoccupied volume can create a significantly flawed product.

4. Sedimentation

Suspension “stability” is most easily achieved buy avoidance of sedimentation (ie. the tendency of particles in suspension to settle out of the fluid). In order to ensure stability, the gravitational pull exerted on particles must be balanced with the “up-thrust” of the fluid. Unstable suspensions can wreak havoc in the food industry, for example, where consistency is essential to product perception.

5. Effectiveness of drug delivery by Inhalation

In order to maintain the integrity of air supply in the body, our respiratory systems are incredibly efficient at filtering out particles above a certain size. This stops these particles from entering and damaging the lungs. Orally or nasally inhaled drug manufacturers must ensure the product is capable of penetrating the lungs; conversely, cleaning product manufacturers may need to provide extra controls in order to prevent inhalation if particles are of a dangerous size.

6. Product appearance

The principle behind the particle size analysis technique of laser diffraction is that particles will scatter light in different ways depending on their size. In some industries, however, this principle is important not just for analysis but also for end product — paint manufacturers, for example, must achieve desirable light scattering effects in order to define parameters such as hue, tint, transparency, gloss and so forth.

7. Texture

Overall, the size of particles can have direct correlation with a customer’s perception of a product and, therefore, the reputation of a manufacturing company. This is particularly true in the case of food products in which particle size can impact the enjoyment of the product; take coffee, for example, with which particle size affects the flavours released in the brewing process.