Sorption in an ammonioalunite-ammoniojarosite solid solution: results for the 1, 2, 4, 7, 11, 12 and 13 group elements and LREEs

Abstract

This paper collates selected analytical results from a 1-year sorption experiments conducted on natural samples of an ammonioalunite-ammoniojarosite solid solution (AAJ) of known initial composition. These include Electron Microprobe (EPMA)  and Powder X-Ray Diffraction (PXRD) results for baths subjected to Li2SO4·H2O, KI, Rb2CO3 (0.33–0.62 wt.% Rb2O in the AAJ, CsCl (0.24–1.07 wt.% Cs2O), Ca(OH)2 (ettringite formation), Sr(NO3)2 (0.31–10.25 wt.% SrO), ZrO(NO3)2·2H2O, MnSO4·H2O, CuSO4·5H2O (up to 1.05 wt.% CuO), ZnCl2, Ga(NO3)3·9H2O (5.86-21.44 wt.% Ga2O3), ZrCl4 (up to 17.56 wt.% ZrO2 in AAJ, i.e., up to 0.27 apfu Zr, InCl3 (0.85–17.04 wt.% In2O3, i.e., possibly up to 0.42 apfu), KH2AsO4 (up to 45.93 wt.%  As2O5,  recast to 1.64 apfu As), K2SeO3 (up to 44.86 wt.%  SeO2, recast to 1.55 apfu Se), LaCl3·7H2O (0.17–0.22 wt.% La2O3), CeCl3·7H2O (0.38–1.74 wt.% Ce2O3), and PrCl3·6H­2O (1.66–4.10 wt.% Pr2O3). Zn, Mn, and I only rarely show accumulation. (NH4)Fe3(AsO4)2[(OH)4(H2O)2] and (NH4)Fe3[(AsO4)(SO4)][(OH)5(H2O)] are occasionally the dominant hypothetical end-members in the As experiment. In the KI case the resulting material is 1.6 times more enriched in K than the base used. Special attention is paid to Zr, with PXRD and EPMA results not ideally coincident with a trial Scanning Electron Microscopy-Electron Backscatter Diffraction study suggesting deposition of tetragonal ZrSiO4 (synthetic zircon).