TY  - JOUR
AU  - Klinkenberg, Martina
AU  - Brandt, Felix
AU  - Breuer, Uwe
AU  - Bosbach, Dirk
TI  - Uptake of Ra during the recrystallization of barite: a microscopic and ToF-SIMS study
JO  - Environmental science & technology
VL  - 48
IS  - 12
SN  - 1520-5851
CY  - Columbus, Ohio
PB  - American Chemical Society
M1  - FZJ-2014-03264
SP  - 6620–6627
PY  - 2014
AB  - A combined macroscopic and micro analytical approach was applied on two distinct barite samples from Ra uptake batch experiments using ToF-SIMS and detailed SEM investigations. The experiments were set up at near to equilibrium conditions in order to distinguish between two possible scenarios for the uptake of Ra by already existent barite, (1) formation of a Ba1-xRaxSO4 solid solution surface layer on the barite or (2) a complete recrystallization, leading to homogenous Ba1-xRaxSO4 crystals. It could be clearly shown that Ra uptake in all barite particles analyzed within this study is not limited to the surface but extends to the entire solid. For most grains a homogenous distribution of Ra could be determined, indicating a complete recrystallization of barite into a Ba1-xRaxSO4 solid solution. The maxima of the Ra/Ba intensity ratio distribution histograms calculated from ToF-SIMS are identical with the expected Ra/Ba ratios calculated from mass balance assuming a complete recrystallization.In addition, the role of Ra during the recrystallization of barite was examined via detailed SEM investigations. Depending on the type of barite used, an additional coarsening effect or a strong formation of oriented aggregates was observed compared to blank samples without Ra. In conclusion, the addition of Ra to a barite at close to equilibrium conditions has a major impact on the system leading to a fast re-equilibration of the solid to a Ba1-xRaxSO4 solid solution and visible effects on the particle size distribution, even at room temperature.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000337646000013
DO  - DOI:10.1021/es405502e
UR  - https://juser.fz-juelich.de/record/153776
ER  -