Sorption of rare earth elements onto basaluminite: The role of sulfate and pH

Geochemical behavior of rare earth elements in acid drainages: Modeling achievements and limitations

“…Therefore, the aqueous species LnSO 4 + is the overwhelmingly dominant aqueous REE species in all the acidic streams and mixtures. Lozano et al (2019a) performed sorption experiments of REE onto basaluminite at different pH values and SO 4 concentrations. Owing to the predominance of sulfate complexes in the aqueous phase, the experiments were modeled by assuming that the aqueous MSO 4 + complex exchanges with n protons from n surface sites XOH:…”

“…From the experimental values, (Lozano et al, 2019a) proposed a value of n = 1 (monodentate complexes). This result is in agreement with the formation of a monodentate inner sphere complex of the YSO 4 + aqueous species and basaluminite surface, suggested by Extended X-ray absorption fine structure (EXAFS) and high-energy X-ray scattering (HEXS) (Lozano et al, 2019b).…”

“…where the first fraction is the solid:liquid ratio (mg/L), [Al] is the Al concentration (mg/L) of the acidic stream minus that of the mixture; M Al and M bas are the molar masses of Al and basaluminite, respectively; S is the specific surface area (m 2 /mg); σ represents the sites obtained from the basaluminite structure (4.6 sites/nm 2 according to Lozano et al, 2019a); and N A is Avogadro's number. The specific surface area of the precipitates from IPB sites was also determined and ranged from 0.020 to 0.060 m 2 /mg.…”

“…These values were not available for samples from Arroyo del Val. Thus, the specific surface area of these precipitates was assumed to be 0.068 m 2 /mg, the measured value for synthetic basaluminite (Lozano et al, 2019a). The resulting T XOH values are also included in Table 4.…”

“…Recently, Lozano et al (2019a) performed sorption experiments of Sc, Y and lanthanides on basaluminite. Sorption occurred at pH values between 4 and 7 and increased with the SO 4 concentration of the solution.…”