Preparing XRF Samples using Pressed Pellets

[Audio] Preparing XRF samples using pressed pellets.

[Audio] XRF is known as X-ray Fluorescence. It is non-destructive analytical method. Besides that, it is used to identify the elemental composition of materials. By detecting the fluorescence or secondary X-ray that a sample emits when it is activated by a main X-ray source, XRF analyzers may determine the chemistry of a sample. XRF is also a great technology for qualitative and quantitative examination of material composition since each element in a sample emits a distinct collection of characteristic fluorescent X-rays which is called "a fingerprint".

[Audio] Sample Preparation. SAMPLE PREPARATION. 02.

[Audio] Sample preparation is most important as it is able to eliminate the contaminants. Besides that, it is crucial because it can increase the accuracy of the results and decrease the risk of distortion..

[Audio] There are different types of sample preparation like solid samples, loose powders, pressed pellets and fused beads. But, today we will be focusing on pressed pellets..

[Audio] The first step of the sample preparation process is to select a suitable press for the sample. Different press model has different requirement. For example, PR- 25A is used when the samples have a very large volume with very small mass. So that the pressing can be performed in one step. Otherwise, several steps are necessary..

[Audio] During the pressing process, if pressing procedure conducted too quickly, trapped air causes part of the pellet to flake later. Besides, if too much force can lead to pressed pellet remaining stuck to the pressing plate. However, these problems can be overcome by using programmable 40-ton press by slowly building up the pressure in up to three steps, whereby it is also possible to specify a waiting time after each pressing step..

[Audio] Then a pressing die is selected for the sample. It can be classified into 2 categories which are with rings or without rings. Different diameter pressing die has different maximum pressing force. Therefore, it is important to choose a pressing die with correct design according to the press we are using..

[Audio] After that, we grind the sample in different ways to achieve a grain size of less than 100µm which is recommended for XRF analysis of pressed pellets. Different kind of sample uses different type of equipment to grind the sample. For example, jaw crusher, mortar grinder and ball mill can be used to grind a hard and brittle materials..

[Audio] When the sample has been ground, the necessary amount of sample is weighed with the analytical balance..