As a relatively mature component analysis method,X-ray fluorescence spectrometerSpectral analysis in geology, metallurgy, environment, and chemistryWidely used in fields such as engineering and materials. Its analysis objects are mainly block solids, powders, and liquids, among which solid powders are the most analyzed. Because many samples such as cement, coal, dust, etc. are already powders For irregularly shaped block solids Due to the immaturity of direct analysis techniques, they are often crushed into powder. Liquid samples can be placed in liquid sample cups for analysis, but due to reasons such as inability to evacuate, sometimes the liquid is transformed into a solid, and some pre separation and enrichment results are often powder. Therefore, the sampling technique for powder samples isX-ray fluorescence spectrometerAn important research topic in spectral analysis.

X-ray fluorescence spectrometerThere are two main methods for powder samples: powder compression method and melting method. This article mainly introduces the powder compression method. The advantages of powder compression method are simplicity, speed, and economy. It is widely used in the analysis of large workloads and is also commonly used for the analysis of trace elements.

The powder compression sampling method mainly consists of three steps: drying and calcination; Mixing and grinding; Press the tablet. There are methods such as direct powder compression, powder dilution compression, using adhesive substrates, and edging.

When the bonding strength of the sample itself is low, it is important to choose a suitable adhesive.

Common adhesives include：Boric acid, methylcellulose, polyethylene, paraffin, starch, etc.

The amount of adhesive addedaverageFor the sample10 ~50%Excessive amounts can affect the detection limit of light elements. The addition of adhesive will decrease the strength of the analysis line, and if the particle size of the adhesive is large, it will also introduce particle size effect.

General samplesneedCrush to74μmbelow(pass200Eye sieve), can achieve20μ mLeft and right, to reduce or even eliminate granularity effects, canManually grind with agate or tungsten carbide mortar, and now mechanical vibration grinding or ball mill is more commonly used for high efficiency.

Common sampling equipment includes manual or electric hydraulic presses, and powder samples are loaded into aluminum cups or rings(Or plastic ringSteel ring)Press and shape in the corresponding mold.Common pressure:30Ton,20Ton. For very fine and sticky samples, the pressure can be appropriately reduced, for example10Ton. For ferroalloys, the pressure can be appropriately increased, for example40Ton. Common holding time20sGenerally not less than10sExtending the time can slightly improve the sample compression effect, up to a maximum of60s.

1）Plastic ring compression sheet

2）Aluminum ring pressing plate

3）Steel ring compression plate