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Communication Dans Un Congrès Année : 2014

Reactive transport simulation of uranium ISR: effect of the density driven flow

Estelle Bonnaud
  • Fonction : Auteur
  • PersonId : 766028
  • IdRef : 165486597
Vincent Lagneau
Olivier Regnault
  • Fonction : Auteur
  • PersonId : 947811
N. Fiet
  • Fonction : Auteur
  • PersonId : 864832

Résumé

The ISR (in situ recovery) operation of a perched uranium mineralization within a thick, permeable aquifer can become a sensitive issue. Indeed, density difference between the injected high-density acidic solutions and fresh groundwater can bring a high quantity of solutions toward the bottom of the aquifer. This phenomenon has to be taken into account from an operational point of view because the loss of solution can involve both an acid overconsumption and a lower production of uranium; and from an environmental point of view for the remediation of the exploited aquifer. The main topics of this study are: (1) to represent the hydrogeological behaviour of such an ISL operation for quantifying the lost part of uranium and acid linked to the density driven flow, (2) to test the sensitivity of operational parameters (flow rates, well field patterns, positioning of well screens) to optimize the uranium recovery and acid consumption. 3D simulations have been realised with a reactive transport code including a density driven flow module (code HYTEC). The simulations take into account for the reaction processes within the ore body: flow and transport of dissolved reagents, oxidative dissolution of uranium, effect of pH buffers. The results of simulations have shown that the permeability of porous media is a key parameter as it controls the rate of the solution sinking towards the bottom of the aquifer. Using a variety of injection scenarios and geometrical designs, the simulations indicate that possible means to reduce the solutions loss can be identified and tested with such a modelling approach.

Domaines

Géochimie
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Dates et versions

hal-01080767 , version 1 (06-11-2014)

Identifiants

  • HAL Id : hal-01080767 , version 1

Citer

Estelle Bonnaud, Vincent Lagneau, Olivier Regnault, N. Fiet. Reactive transport simulation of uranium ISR: effect of the density driven flow. 7th International Conference on Uranium Mining and Hydrogeology, Sep 2014, Freiberg, Germany. pp.699-704. ⟨hal-01080767⟩
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