Particle size distribution - Ryudobunpu

The ratio of particles belonging to a certain particle size range to the total amount. There are three ways to express the particle size distribution of powders:
(1) Frequency distribution: The ratio of the amount of particles belonging to a certain particle size range to the total amount of particles.
(2) Cumulative distribution (sieve size): The ratio of particles below a certain size to the total amount of particles.
(3) Cumulative distribution (on a sieve): The ratio of particles larger than a certain particle size to the total amount of particles.
Particle quantity is measured using volume, area, length, and number. Particle size distribution was traditionally determined by sieving, but nowadays there are a variety of measurement methods available, such as the following:
(1) Liquid-phase sedimentation methods (centrifugal sedimentation light transmission method, X-ray transmission method, centrifugal sedimentation weight method): A method in which the speed of particles settling in a fluid is observed by light transmission, X-ray transmission, and weight change, and the particle size distribution is calculated from the results.
(2) Laser diffraction scattering method: A method in which a laser beam is irradiated onto particles dispersed in a liquid or gas, and the intensity of the diffracted or scattered light is analyzed based on the Fraunhofer diffraction theory or the Mie scattering theory to calculate the particle size distribution.
(3) Light blocking method: A method of calculating the particle size distribution by detecting the amount of laser light blocked by particles.
(4) Electrical detection method: Particles are suspended in an electrically conductive liquid such as an electrolyte solution, and the volume and number of the particles are electrically detected.
(5) Optical correlation method: A method for analyzing particle size by calculating the diffusion coefficient of a particle from the change over time in the scattering intensity of light scattered by the particle.
(6) Chromatography: A method in which a sample is introduced into a liquid flow, and particles are separated by size using the velocity distribution in the laminar flow, and their concentration is measured using light transmission methods, etc.
(7) Image analysis method: A method of analyzing microscopic images and calculating particle size distribution.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

ある粒子径範囲に属する粒子の全体量に対する割合．粉体の粒度分布の表示法としては次の三通りがある．
(1)頻度分布：ある粒径範囲に属する粒子量の全粒子量に対する割合，
(2)積算分布(ふるい下)：ある粒径以下の粒子量の全粒子量に対する割合，
(3)積算分布(ふるい上)：ある粒径以上の粒子量の全粒子量に対する割合．
粒子量としては，体積，面積，長さ，個数が用いられる．粒度分布は古くはふるい分けにより求められてきたが，現在では，次にあげるようなさまざまな測定法がある．
(1)液相沈降法(遠心沈降光透過法，X線透過法，遠心沈降重量法)：流体中を沈降する粒子の速度を光透過，X線透過，重量変化により観測し，それから粒度分布を算出する方法，
(2)レーザー回折散乱法：液体あるいは気体に分散された粒子にレーザー光を照射し，回折あるいは散乱される光の強度を，フラウンホーファー回折理論やミー散乱理論にもとづき解析し，粒度分布を算出する方法，
(3)遮光法：粒子にさえぎられたレーザー光の光量を検知して，粒度分布を算出する方法，
(4)電気的検知法：電解質溶液などの電気伝導性のある液体中に粒子を懸濁させ，その粒子の体積と個数を電気的に検知する方法，
(5)光相関法：粒子により散乱される光の散乱強度の経時変化から粒子の拡散係数を算出し，粒子の大きさを解析する方法，
(6)クロマトグラフィー：液体の流れに試料を投入し，層流に存在する速度分布を利用して粒子を大きさ別に取り出し，その濃度を光透過法などで測定する方法，
(7)画像解析法：顕微鏡画像を解析し，粒度分布を算出する方法．

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