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  Following the introduction of routine analysis of metal samples by spectrometer, efforts were made to analyse non-metallic substances with the same instruments. No supplementary equipment was to be used for this purpose. There have been numerous proposals, of which most involve fusion. This is always necessary if no internal reference can be used. Simply adding a reference to the mixture has never led to sufficient homogeneity.

  The sample preparation stages are:

  1. About 15 g slag is taken; this is placed in a clean grinding container; 10 ml Freon is added; and the container is closed.

  2. The grinding vessel is placed in the swing mill and grinding is carried out for 1 min.

  3. The ground sample material is placed on a clean piece of paper and a few g are passed through a < 60μm sieve. This eliminates metal flakes.

  Further sample preparation is carried out as described.

  Note:

  a) The used utensils must be cleaned before preparing a new sample. After mechanical cleaning, further “cleaning” can be carried out by placing about 15 g of the new slag sample in the grinding container and grinding for 1 min; the ground material is then discarded.

  b) The use of Freon is not absolutely necessary but facilitates cleaning and removal of the ground product. Alcohol can be used as an alternative.

  c) Two grinding containers should be used-one for grinding the raw sample, the other for mixing the sieved sample with graphite.

  Analysis results:

  For the analysis, slags with the following elements and concentration ranges of oxides were used;

  Calibration was carried out with international reference samples and using secondary reference samples analysed by wet chemistry for converter and blastfurnace slags.

  The RSD for concentrations＞BEC are about 1-3%.