XRF analysis is actually a surface analysis method. Excitation occurs only on the shallow surface of the sample, so it must be noted whether the analysis surface is representative of the entire sample. The average granularity and granularity distribution of the sample are of great importance. The smaller the sample granularity , the smaller the granularity of the same element, the better the stability of the sample preparation, but it means greater difficulty of grinding. In practical applications, the granularity is generally required to be less than 200 mesh.

In sample processing for XRF analysis at present, the vibratory disc mill (or called vibration mill, vibration grinder, vibratory disc mill) or ball mill is more used. Compared with a ball mill, a vibration mill has higher efficiency. Grinding for a few minutes is enough to meet the granularity requirements, but it takes a ball mill half an hour or more. As to the vibration mill, the general sample can be crushed to 74 ¦Ìm or less(through 200 mesh sieves), while the best can reach about 20 ¦Ìm.

This vibratory disc mill works with pressure, impact force and friction force. The grinding kit is fixed by a fast locking device to the vibration chassis which is designed with an eccentric rotating mechanism. The vibration chassis and the grinding kit make a circular vibration motion on the horizontal plane. Then the grinding parts located in the grinding jar generate considerable pressure, impact force and friction force through this vibration motion and these forces act on the sample to pulverize material within a few minutes.

We prepared some food for grinding test. The grinding effect can be seen in the table below.

1. With the grinding results of several experiments, we can see that most dry, brittle and hard food samples can meet the granularity requirements.We can draw conclusions as bellows:

2. Though chestnuts are oily and sticky, the ground granularity can also reach about 1mm.

3. The host runs very smoothly with no displacement(even in the maximum speed of 1400 rpm for a long time).

4. In terms of grinding quality, the final granularity of the sample is basically below 200 mesh at 1200rpm for 3min. As to the some dry and brittle sample, it takes even shorter grinding time and lower rotation speed.

In short, the PrepM-01 vibration mill can quickly grind dry, hard and brittle samples down to  200 mesh or below, yet it is not applicable to samples with low melting point or wet samples. In theses conditions, low-temperature grinding will contribute to achieve the goal of 200 mesh or below.