Granulometry is linked to the size of the particles in a sample.
Granulometry is a concept that is formed from two terms: the noun granule and the compositional element -metry . By analyzing both parts, it is easy to understand what granulometry is.
Granule , from the Latin granŭlum , is the diminutive of grain and is used to refer to a small particle . As for -metry , it means “measurement” or “measurement” .
With these ideas clear, we can move forward with the notion of granulometry. This is the name given to the size of the particles (grains, stones, etc.) that are part of the dust or aggregates. Granulometry is also the branch of petrography that studies the measurement of the size of rocks and particles present in the soil.
Granulometry as a discipline
We said that granulometry is an area of petrography . At this point it is important to mention that petrography is the study of rocks (solid materials that develop naturally and are made up of a mineral or a set of minerals).
Granulometry can be understood, in this framework, as a discipline or a type of study. In general, it is dedicated to analyzing how the sizes of the elements that are part of a sample are distributed.
The operations carried out in granulometry constitute what is known as granulometric analysis . These actions include sieving the sample, determining the mass of the fragments retained in the different shades and calculating each percentage retained.
The results are expressed by numbers and represented with graphs or tables that indicate how the particle sizes are distributed. It is important to clarify that, in addition to sieving, there are other techniques that can be used in granulometry, such as laser diffraction and centrifugation .
The granulometric curve allows representing the results of the analysis carried out.
Usefulness of granulometric analysis
Various sciences and industries appeal to granulometry to generate important knowledge. Geology , for example, manages to obtain information from the materials that make up the soil.
The granulometry of a terrain allows us to appreciate the level of impermeability of a soil, to mention one possibility. The oil industry, meanwhile, needs granulometry to carry out drilling and to know under what conditions it will operate.
The granulometry curve
The representation of the results of the granulometry done in the laboratory is called the granulometric curve . This graph is key in the analysis of soil structure that takes into account the size of the particles.
To draw the granulometric curve, sieves are used that have standardized openings and allow the particles to be separated. The next step is to weigh the quantities that were left in the different sieves.
The size corresponding to the highest frequency is called the mode or mode . The size corresponding to 50% of the cumulative distribution, on the other hand, is called the median .
According to the granulometric curve and the most used classification methods, we can distinguish between clay , sand , gravel , etc. These classifications are defined according to the dimensions of their fundamental particles, measured in millimeters.