@article{fdi:010093454,
  title = {{C}onfirmation of the retention of 226{R}a in {U}-mine tailings by barite},
  author = {{B}esan{\c{c}}on, {C}. and {G}{\'e}rard, {M}artine and {L}ahrouch, {F}. and {H}ughes, {K}. and {S}ardini, {P}. and {S}avoye, {S}. and {D}escostes, {M}.},
  editor = {},
  language = {{ENG}},
  abstract = {{U}ranium ore from the {A}thabasca basin in {S}askatchewan {C}anada, particularly from the {M}c{C}lean {L}ake and {C}igar {L}ake deposits, is extremely rich in uranium ({U}): 2 to 20-25 % {U}3{O}8. {T}he ore is also rich in many elements considered to be {C}onstituents of {P}otential {C}oncern ({COPC}) for the environment, including arsenic ({A}s), selenium ({S}e), nickel ({N}i), molybdenum ({M}o), lead ({P}b), cobalt ({C}o) and radium-226 (226{R}a). {F}ollowing uranium extraction, residual materials (tailings) containing these elements in partially immobilized forms are placed in the {M}c{C}lean {L}ake plant {T}ailings {M}anagement {F}acility ({TMF}). {U}ranium tailings are sulfate-rich low-level radioactive waste containing 226{R}a, with activities of up to 3000 {B}q/g. {B}arium chloride ({B}a{C}l2) is added to precipitate 226{R}a in barite as a solid-solution. {F}ollowing this neutralisation treatment, 226{R}a in the tailings is generally considered as sequestered in barite and sorbed onto ferrihydrite. {T}o assess the subsequent stability of 226{R}a in the tailings, an extensive study of its retention potential was performed. {C}haracterisations incude assessment of tailings pore water and solids chemistry, tailings mineralogy, cation exchange capacity measurement, scanning electron microscopy and energy-dispersive x-ray spectroscopy ({SEM}/{EDS}), and alphaautoradiography analyses supplemented with thermodynamic modelling. {T}his work confirms that barite is the main 226{R}a binding-phase, in agreement with the 226{R}a concentration measured in the porewater (6 {B}q/{L}) resulting from a coprecipitation reaction. {A} ({B}a,{R}a){SO}4 solid-solution regulates the average 226{R}a concentration now and over the long term, through a distribution coefficient which is subject to a gradual shift towards a recrystallisation equilibrium. {R}ecrystallisation causes an increase in the long-term concentration of 226{R}a in the tailing water to 10 {B}q/{L}. {T}he work, conducted to assess the management strategy of the tailings, allowed us to ensure that the tailings have no significant effects on the downstream environment over the long term.},
  keywords = {{U}ranium mining ; {T}ailings ; 226{R}a ; {S}olid-solution ; {A}lpha-autoradiography ; {B}arite ; {CANADA}},
  booktitle = {},
  journal = {{J}ournal of {H}azardous {M}aterials {A}dvances},
  volume = {18},
  numero = {},
  pages = {100716 [14 p.]},
  ISSN = {2772-4166},
  year = {2025},
  DOI = {10.1016/j.hazadv.2025.100716},
  URL = {https://www.documentation.ird.fr/hor/fdi:010093454},
}