Particle Size Analysis – What You Need to Know

Particle size analysis has many important uses for many industries. While many people may not immediately recognise or understand the benefits of determining particle size and shape, processes and systems in a variety of industries are enhanced and made more efficient when this intelligence is known. Specialised equipment has been developed to assist with such analysis and is vital in ensuring quality control and product standards.

What is Particle Size Analysis used for?

Particle size analysis is used to learn more about the size and shape of grains and particles within a particular sample. This analysis is so sophisticated and versatile that it is applicable to solid materials and also suspensions, emulsions and aerosols.

As some particle size analysis methods can only be used for particular materials, it is important that the most appropriate method of analysis be used. Varying and inconsistent results can occur if an inappropriate method for determining size is used.

What are Particle Size Analysis results used for?

Quality control and efficient functioning of processes is better assured for many industries if particle size analysis testing is done. For any industry where milling or grinding is undertaken, it is important to know particle size and shape in order to maximise the efficient functioning of processes and the ultimate quality of products.

While an array of industries and products benefit from particle size analysis, some of the industries in which analysis is commonly and widely used are:

• Pharmaceutical
• Building
• Paints and coatings
• Food and beverages
• Aerosols

What are some of the difficulties with Particle Size Analysis?

Problems can arise when particle size analysis attempts to reduce the size of particles to only one number. A two dimensional graph is usually used to report particle size and quantity. However, only the shape of a sphere can truly be expressed as a single number, as it is the only shape that has the same measurement across every dimension. This does not apply to shapes of other types and sizes; they do not consistently measure the same across all of their dimensions.

In light of this, a one dimensional property of a particle is related to the size of an ‘equivalent sphere’ in all particle sizing techniques. Commonly, the volume of each particle in a sample is measured and equated to the size of a sphere with the same volume as the measured particles. This is referred to as an ‘equivalent sphere’ and is often applied in laser diffraction methods.

What is Laser Diffraction?

One of the most often used particle sizing methods, laser diffraction operates from the principle that when a laser (beam of light) is broken and scattered by particles, the smaller the particle size, the larger the angle of light scattering will be.

Laser diffraction is so popularly used because of its application to many different sample types. Further advantages of this particle size analysis technique are that it is fast, reliable and a technique that can be reproduced. It is also possible to use this measurement technique over a wide size range.

Particle size analysis is vital for enhancing the processes used in a variety of industries. Modern, sophisticated equipment is specifically designed to provide accurate and reliable results pertaining to a range of materials. It is little surprise that particle size analysis is so popularly used when the specific information that it provides are so significant and important to companies and industries.