Grain size / grain size analysis
Grain size or particle size plays an important role in bulk material sampling for the following reasons:
- Representativeness: As mentioned earlier, grain size can affect the representativeness of a sample. If the bulk material consists of a variety of grain sizes, it is important to obtain a sample that represents this diversity. Otherwise, the sample may not accurately reflect the composition of the total bulk material.
- Performance of the sampling equipment: The grain size can also affect the performance and efficiency of the sampling equipment. For example, very large particles could cause the sampler to become blocked, while very small particles could cause the sample to be blown away by wind or other external forces.
- Analysis and Use: The grain size may affect the subsequent analysis and use of the sample. For example, the size and shape of the particles could have an impact on physical properties such as permeability, flowability or compaction.
A grain size analysis can be performed in a variety of ways, depending on the type of bulk material and the accuracy required. Some of the most common methods are:
- Sieve analysis: This method uses a series of sieves with different mesh sizes. The bulk material is placed on the top sieve and then shaken so that smaller particles fall through the meshes and are collected in the sieves below. At the end, the weight or volume of the material in each sieve is measured to determine the grain size distribution.
- Laser diffraction analysis: This method uses the diffraction of light to determine particle size. A sample of the material is dispersed in a liquid medium and then exposed to a laser beam. The way the light is diffracted by the particles provides information about their size.
- Image analysis: This involves taking an image of the particles and then analyzing it with special software to determine the size and shape of the particles.
These methods each have their own advantages and disadvantages and are suitable differently depending on the type of bulk material and the specific requirements of sampling.