Sieve Analysis

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Sieve Analysis - Particle Size Distribution

High-Throughput Experimentation (HTE)

 

Sieve Analysis Workflow

Preparation steps
1. Method development: based on the material to be tested, choose a suitable standard method, select the appropriate sieves in the stack to ensure uniform distribution on each sieve, and determine the required sample quantity. Preliminary tests can help specify these parameters
2. Preparation of sieves or stacks, e.g., pre-recording of the sieves (identification and tare weight)
3. Sampling
4. Sample preparation, e.g., pre-drying, conditioning or sample division

Sieve weighing steps
5. Weigh sieves empty, from bottom to top or from the pan (A), the smallest mesh size (B) to the largest mesh size (E); identify every sieve, subtract tare
6. Add the sample
7. Sieving (manually or using the sieve shaker)
8. Back weigh fractions in every sieve, from top to bottom or from the largest mesh size to the smallest mesh size
9. Result analyses, evaluation, and interpretation

Equipment maintenance
Like other precision measuring instruments in the laboratory, test sieves require regular care to maintain the standard of performance, this includes:

  • Careful cleaning after each run
  • Performance checks prior to use and periodic routine checks, e.g., testing with proficiency test samples
  • Calibration: Periodic calibration and recertification of test sieves (ASTM E11 or ISO 3310-1).

 

Sieve Analysis Results

Static Image Analysis (SIA) is primarily used to measure narrow size distributions, with an emphasis on characterizing very fine particles. It provides high-resolution particle images that allow an extremely accurate description of size and shape, but it is time-consuming. SIA is mainly used in research and development.
Standard: ISO 13322-1.

Dynamic Image Analysis (DIA) is a number-based particle characterization method, applicable for samples larger than about 1 µm. If smaller particles are also to be measured, Laser Diffraction (LD) is the method of choice. DIA is a modern particle size characterization method ideally suited for routine measurements of bulk goods, powders, granules, and suspensions. In many industries, the DIA has already replaced traditional sieve analysis.
Standard: ISO 13322-2.

Static Light Scattering (SLS) or Laser Diffraction (LD) can determine volume-based distributions, pharmaceuticals (API), and PSD in liquids and slurries. Laser Diffraction is the most common method for the determination of particle size distributions other than traditional sieve analysis. It is based on the deflection of a laser beam by an ensemble of particles dispersed in either a liquid or an air stream.
Standard: ISO 13320.

Dynamic Light Scattering (DLS) is based on the Brownian motion of dispersed particles in solution. It is a non-invasive technique for measuring the size and size distribution of molecules and particles typically in the submicron range.
Standard: ISO 22412.

 

Sieve Analysis Experts

 

Sieve Analysis Challanges

 

Sieve Analysis - Balances and Software

 

Sieve Analysis Guide Free PDF

FAQ

Frequently Asked Questions on Sieve Analysis

What is the recommended sample size to be used for sieve analysis?

In sieve analysis experiments, there is often a tendency to use samples that are too large, as it is assumed that this will make the test results more accurate. However, this compromises the accuracy of the result, as each individual particle does not have the opportunity to present itself on the surface of the test sieve. Generally, a 25–100 g sample is recommended. A procedure exists to help establish the appropriate sample size, using a sample splitter to reduce the sample to different weights (25 g, 50 g, 100 g, 200 g), and testing samples in the various weight ranges. If the test with a 50 g sample shows approximately the same percentage passing the fine sieve as a 25 g sample, whereas a 100 g sample shows a much lower percentage passing, this would indicate that the 50 g sample is the appropriate sample size.

What is the difference between sieve diameters in ASTM standards vs. ISO/BS standards?

In the ASTM standards, sieve diameters are measured in inches, while millimeters are used in the ISO/BS standards. There is a slight difference between 8 inches and 200 mm or 12 inches and 300 mm diameter. In reality, 8 inches equals 203 mm and 12 inches equals 305 mm. Therefore, test sieves with a diameter of 8 inches and 200 mm cannot be nested, nor can test sieves with a diameter of 12 inches and 300 mm.

What are the differences between mesh numbers and wire spacing in ASTM standards vs. ISO/BS standards?

Mesh number represents the number of wires per inch (25.4 mm). Woven wire sieves are sold either by mesh number or by the wire spacing. The ASTM American standards use mesh numbers, whereas ISO/BS International and British standards tend to use wire spacing.

How does air humidity in the lab affect sieve analysis?

Very dry conditions can cause fine powders to adhere both to the sieve components and to each other with strong electrostatic charges. Ideally the relative humidity (% RH) should be between 45% and 60%. 

What are the advantages of sieve analysis over alternative techniques, like image analysis methods?

The advantages of sieve analysis include low investment costs, easy handling, precise and reproducible results in a relatively short time and the ability to separate the particle size fractions. Therefore, this method is commonly used instead of methods using laser light or image processing.

What are the limitations of sieve analysis?

One limitation is the number of size fractions obtainable, which limits the resolution. A standard sieve stack consists of a maximum of 8 sieves which means that the particle size distribution is based on just 8 data points. Further limitations are that this technique only works with dry particles, the minimum limit of measurement is 50 µm, and the method can be rather time-consuming.