This part of EN 725 specifies methods for the determination of the levels of silicon, aluminium, titanium, iron, calcium, magnesium, potassium, sodium, yttrium, hafnium, cerium and strontium using flame atomic absorption spectrometry (FAAS) and inductively coupled plasma atomic emission spectrometry (ICP - AES). These methods are applicable to the concentration ranges given in clause 3, expressed as oxides.