polab® APM- Sample preparation for cement laboratory automation

Pressed tablets are the common way to prepare samples for both XRF and XRF analysis in the cement and other industries. In many cases the same pressed tablet can be used for both analysers, thus reducing cost and sample preparation time. Fused beads prepared from flux cannot be used for XRD analyses, and due to preparation time and reagent requirements have a cost of approximately 10 times that of a pressed tablet.

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polab® APM - advantages at a glance

  • Combined mill and press in one small unit with a minimum footprint of only 600 x 1230 x 735 mm (23.6 x 48.4 x 28.9 ″; W x H x D)

  • Patented grinding unit for efficient and gentle grinding, and optimized sample preparation for the different requirements of XRF and XRD

  • Excellent reproducibility

  • High sample throughput and integrated ring cleaning device for APMplus

  • Predefined automatic and user-specific sample preparation routines

  • Operator panel for simple and intuitive operation

  • Grinding and pressing functions can be selected in a combined process or as single processes

Operation

For pressed tablet preparation the sample is ground to analytical fineness, typically d90 < 30µm and mixed with a grinding aid and binder combination. The binder also enables good automated cleaning of the equipment, and makes tablets stable under vacuum, as required in XRF systems. After grinding, the sample is pressed into a steel ring. This steel ring is transferred to an XRF or an XRD analyser where the analysis is conducted using best practices. After analysis, the steel ring is returned, cleaned and re-used for a new sample. The steel ring sample is the best compromise for maintaining a high sample load, assuring minimum cost and maintaining reliable analytical quality for process supervision. Since its launch in 2002, the polab® APM has become the standard for preparing XRF and XRD tablets, and hundreds of APMs are in use around the world.

Low-wear grinding vessel

Wear is the most critical issue in grinding tools. Material wear causes a shift in analytical results over time. This generates additional work for recalibration and increased cost for replacing and maintaining worn grinding vessels. thyssenkrupp carried out long-term testing of various tungsten carbide grades to find the grade that is our standard today. Grinding vessels with minimum wear assure good grinding properties and minimum spare part requirements. Today it is difficult to know how many samples can be processed in one grinding vessel, but the number is considerably higher than 40,000 – 50,000 samples without changes in analytical results.