COUPLING OF MASS-TRANSFER EQUATIONS AND SOLUTION SOLID INTERACTION LAWS BY USING LANTHANIDES AS TRACERS - AN EXPERIMENTAL APPROACH

In underground flow tracing studies, the estimation of the nature and the importance of interactions undergone by the substance used very often constitutes an obstacle to good modeling of mass-transfer processes in solution. A method is proposed to quantify these phenomena by the use of lanthanides as tracers. For this study, an analytical methodology adapted to routine measurements was set up. The quality of 5 lanthanides as indicators was examined. The formation, by substitution, of a carbonate complex which is extremely stable in the natural environment was demonstrated. The field experiments carried out demonstrated the efficiency of those tracers and confirmed their great stability. Tracer recovery graphs show that convection and dispersion are identical for all the lanthanide elements. A direct relation was established between their fixing rate on earth materials and the value of their stability constants. Thus, the possibility of correlative multitracing, with known and quantifiable interelement relations, is demonstrated.