The application of batch extraction tests for the characterisation of solidified ferro alloy waste products

The errors in results from the pore solution expressions and sequential chemical extractions were too high to draw any quantitative conclusions, although some qualitative comments could be made. The latter observations, however, were consistent with those from the other two tests, and together these build a comprehensive picture of the S/S products. For these specific products, it is suggested that a small amount (∼1%) of the Cr is Cr(VI) which is readily mobile, approximately 5% is Cr(III) which is mobile under acidic conditions and the remainder is a stabile chromite which is not readily mobile. For Zn, however, roughly equal proportions are contained as a species (possibly Zn(OH)2) whose release is pH dependant, and as a stable, immobile species on the surface of the dust particles.