Freezer Mill ideal for modified RoHS regulations

The RoHS Directive is an EU directive for the restriction of hazardous substances in electronic products. RoHS is an abbreviation of Restriction of Hazardous Substances. Until recently, this directive listed 6 heavy metals that could be restricted in products by manufacturers of these devices. Four phthalates have now been added to these heavy metals for the RoHS3 version.

For years the Freezer/Mill of manufacturer SPEX SamplePrep has been grinding electronic & electrical components (for heavy metals) and plastic children’s toys & care products (for phthalates) into a homogeneous fine powder. This fine powder ensures efficient extraction of residues at low level and is therefore an ideal device to prepare samples for further downstream analysis. The Freezer/Mill therefore plays an important role in demonstrating whether the individual components and end product are produced in accordance with RoHS regulations.

The EU RoHS3 specifies maximum levels for the following 10 restricted substances:

  • Cadmium (Cd): < 100 ppm
  • Lead (Pb): < 1000 ppm
  • Mercury (Hg): < 1000 ppm
  • Hexavalent chromium: (Cr VI) < 1000 ppm
  • Polybrominated biphenyls (PBB): < 1000 ppm
  • Polybrominated diphenyl ethers (PBDE): < 1000 ppm
  • Bis(2-Ethylhexyl) phthalate (DEHP): < 1000 ppm
  • Benzyl butyl phthalate (BBP): < 1000 ppm
  • Dibutyl phthalate (DBP): < 1000 ppm
  • Diisobutyl phthalate (DIBP): < 1000 ppm

The first six were already applicable to the original RoHS, while the last four were added under RoHS 3, which came into force on 22 July 2019.

In order to comply with these new regulations, companies and local authorities will have to test products to ensure compliance.

Waste from Electrical and Electronic Equipment

Related to RoHS is the WEEE, which stands for Waste from Electrical and Electronic Equipment. The WEEE Directive 2002/96/EC requires the treatment, recovery and recycling of electrical and electronic equipment (90% goes to landfill). All electronic products on the EU markets must comply with the WEEE standard and carry the “Wheelie Bin” sticker.

Functioning Freezer/Mill:

The sample is placed in a special fully sealable Grinding Vial and immersed in liquid nitrogen to reach cryogenic temperatures. The sample is then pulverized by a stainless steel impacter which is magnetically beaten back and forth against two stationary end plugs of the vial by induction. Because the vial is immersed in liquid nitrogen throughout the grinding cycle and is tightly sealed, it retains hazardous and volatile substances and does not cross-contaminate other samples.

Special chromium-free vial sets are available for analysis of the elements. (Of course no Hg, Cd, or Pb is present in these sets either)

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