caa a22 4500 465748945 CHVBK 20180323111828.0 cr unu---uuuuu 170327e19900101xx s 000 0 eng 10.1007/BF00322501 doi (NATIONALLICENCE)springer-10.1007/BF00322501 The development of cryo-grinding equipment for the transformation of large quantities of biological reference materials with low heavy metal contents [Elektronische Daten] [G. Kramer, J. Pauwels] Summary: Conventional devices used for crushing or grinding of large quantities (up to 200 kg) of biological reference materials to be certified for trace metals can cause severe and heterogeneous contaminations by metals as well as losses of trace elements by excessive heat generation. In such cases cryogenic processing and homogenisation is a useful technique, but in general it has been used only for relatively small quantities. This paper describes the development of equipment with a production capacity of 3 kg/h, and its use for the production of a BCR codfish RM. It consists of: 1. A laboratory jaw crusher in which all parts in contact with the material to be processed are made of teflon or KELF. During the crushing process both the crushing chamber and the material are continuously cooled below the brittle point using liquid nitrogen. 2. The enlarging of a commercial planetary ball mill with bowls and balls made of teflon, which are cooled using liquid nitrogen to temperatures below −60°C during operation. The optimisation of parameters such as the number of balls and their diameter, amount of material per bowl, cooling time, rotation speed and milling time are discussed. Springer-Verlag, 1990 Kramer G. Commission of the Euopean Communities, Joint Research Centre, Central Bureau of Nuclear Measurements, B-2440, Geel, Belgium aut Pauwels J. Commission of the Euopean Communities, Joint Research Centre, Central Bureau of Nuclear Measurements, B-2440, Geel, Belgium aut Fresenius' Journal of Analytical Chemistry Springer-Verlag 338/4(1990-01-01), 390-393 0937-0633 338:4<390 1990 338 216 https://doi.org/10.1007/BF00322501 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00322501 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kramer G. Commission of the Euopean Communities, Joint Research Centre, Central Bureau of Nuclear Measurements, B-2440, Geel, Belgium aut NATIONALLICENCE 700 1- Pauwels J. Commission of the Euopean Communities, Joint Research Centre, Central Bureau of Nuclear Measurements, B-2440, Geel, Belgium aut NATIONALLICENCE 773 0- Fresenius' Journal of Analytical Chemistry Springer-Verlag 338/4(1990-01-01), 390-393 0937-0633 338:4<390 1990 338 216 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer