wAbstract
@In order to determine trace metal release, dissolution experiments
were conducted with a natural jarosite-group sample under a range
of conditions relevant to acid sulfate soils. The reaction is
incongruent with respect to the Fe3+-dominant octahedral
cation layer and other elements that substitute for ferric iron.
Transition metals that substitute into the octahedral site are
almost entirely retained in the solid phase, although when Fe3+
becomes increasingly soluble, Cr3+ concentration also
increases
@The solubility behaviour of Rb+ band Sr2+
generally follows that of K+ although the heavier cations
are liberated faster in the early stages of the reaction. The
REE are also large enough to substitute for K+, but
their behaviour is more complex. The REE distribution of the solutions,
when normalized to Post-Archean Average Australian Shale (PAAS),
show enrichments in the MREE in the dissolution experiments, despite
the fact that the initial starting material is enriched in the
LREE. Mechanisms for LREE and HREE depletion in solution are discussed.
Keywords: Jarosite; Trace metals; Rare earth elements; Acid sulfate
soilsx
1. Introduction
2. Methods
@2.1. Experiments
@2.2. Analysis
3. Results
@3.1. Results of dissolution experiments
@3.2. Major ions
@3.3. Trace elements
@3.4. Rare earth elements
@3.5. Reaction stoichiometry
4. Discussion
@4.1. Trace metals
@4.2. REE geochemistry
5. Conclusion
Acknowledgements
References