Determination of Iron in Steel Slag by Standard Addition- Atomic Absorption Spectrometry

Standard addition-atomic absorption spectrometry (AAS) was used to determine Fe content in steel slag samples after sample digestion with HNO₃-HF mixed acid. The homogeneity of slag and other interfering factors on the determination results were studied. It was found that high dilution factors caused by high matrix and high Fe content of the samples lead to a large error. Standard addition-AAS method could avoid the large detection error. And use of AAS instrument with rotating burner and selection of secondary sensitive spectral lines were also recommended to reduce the detection error by reducing the detection sensitivity of Fe. The method has been applied to the determination of Fe in a steel slag sample and the result was compared with those from XRF, ICP-AES and AAS (without standard addition). The results show that standard addition-AAS can provide accurate and reliable results and is superior to the other methods for the samples with high matrix and high Fe content.