Application des tests de lixiviation (NF X31-210) à des roches granitiques
Résumé
Leaching tests of natural materials (granites) were carried out according to the experimental procedure recommended by the AFNOR NF X31-210 French standard relative to the characterization of ultimate industrial stabilised waste. The rocks were selected for: (i) their representativity of the main granite types outcroping at the earth's surface, (ii) their higher content in some elements compared to average compositions considered as toxic, however corresponding to important volumes of material (granite), (iii) their degree of alteration (samples have been selected in the B and C horizons of a soil profile developed on a granite rock). The cations solubilized into the aqueous solutions after leaching test were analyzed by ICP-MS. Fifteen metallic elements were determined : Cr, Mn, Co, Ni, Cu, Zn, As, Au, Ag, Cd, Sb, Hg, Pb, Th and U. Results of the cation analyzes allowed: (i) to estimate the leachability of the main toxic elements in granite rocks, (ii) to determine the different parameters controlling the solubility of these elements, (iii) to compare these results with the standard imposed to the industry for ultimate stabilized wastes. The most easily leached elements were Mn, As and U in altered or fresh granites. The main parameters controlling the solubilization of a given element were: the texture of the rock (mainly the grain size), the nature of the mineral phase in which the element was incorporated and the degree of alteration of the material. The concentrations obtained in the leachates were in the range 0.0001 - 32 mg/kg of matter.
Cette étude se propose de comparer les seuils de concentration en éléments toxiques fixés par les normes légales industrielles avec les quantités de matières libérées par des matériaux naturels lors de l'application des tests de lixiviation. Les échantillons choisis pour cette étude sont un granite sain et un profil pédologique sur un massif granitique. Le granite sain et le profil pédologique ont été sélectionnés pour leur représentativité (Correns et al., 1978), leur teneur élevée en certains éléments considérés comme toxiques (mais correspondant toutefois à des volumes de matériaux importants) et leur degré d'altération.
Domaines
Ingénierie de l'environnementOrigine | Fichiers produits par l'(les) auteur(s) |
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