There are various methods for calculating particle size distribution, and the following are some common methods:

Calculation based on laser particle size analyzer data

Principle: Laser particle size analyzer measures particle size and distribution by utilizing the scattering or diffraction phenomenon of particles on laser. When a laser beam is irradiated onto a particle sample, particles of different sizes will cause the laser to scatter or diffract at different angles. By measuring the intensity distribution of these scattered or diffracted lights, the particle size distribution can be calculated.

Calculation process: The instrument will use specific algorithms (such as Mie scattering theory, Fraunhofer diffraction theory, etc.) to invert and calculate the particle size distribution based on the measured scattering or diffraction intensity data. Usually, the particle size range is divided into multiple intervals, and the relative content or volume fraction of particles in each interval is calculated to obtain the particle size distribution curve.

Calculation based on screening method data

Principle: The sieving method separates particles of different sizes by passing them through a series of standard sieves with different pore sizes.

Calculation process: First, weigh the mass of particles intercepted on each sieve, and then calculate the percentage of particle mass within each sieve size range to the total sample mass. The particle size distribution curve can be drawn by using the sieve size as the horizontal axis and the mass percentage of particles in each interval as the vertical axis. It is also possible to further calculate the cumulative sieve residue percentage, which is the cumulative percentage of particle mass above a certain sieve size to the total mass, in order to more comprehensively describe the particle size distribution.

Calculation of data based on image analysis method

Principle: Image analysis method is to obtain images of particles through equipment such as optical microscopes and electron microscopes, and then analyze and measure the particles in the images.

Calculation process: Using image analysis software to process particle images, such as binarization, edge detection, etc., to identify the contours of each particle. Then measure the equivalent diameter and other parameters of each particle, and based on the set particle size range, calculate the number or area percentage of particles in different particle size ranges to obtain the particle size distribution.

Calculation based on dynamic light scattering method data

Principle: The dynamic light scattering method is based on the Brownian motion of particles in a solution. When the laser irradiates the particle solution, the Brownian motion of the particles will cause fluctuations in the scattered light intensity over time. By measuring these fluctuations in light intensity, the particle size distribution can be analyzed.

Calculation process: The instrument measures the autocorrelation function of scattered light intensity, and then converts the diffusion coefficient into particle size using the Stokes Einstein equation based on the relationship between the correlation function and the particle diffusion coefficient, thereby obtaining the particle size distribution. Multi dispersed system algorithms are usually used to process data in order to obtain more accurate particle size distribution results.

Each of the above methods has its own scope of application and advantages and disadvantages. In practical applications, it is necessary to choose an appropriate method based on factors such as particle properties, sample size, and measurement accuracy requirements to calculate particle size distribution.