Effect of boron oxide addition on the Nd3+ environment in a Nd-rich soda-lime aluminoborosilicate glass

Lanthanum and Neodymium Solubility in Simplified SiO2–B2O3–Na2O–Al2O3–CaO High Level Waste Glass

“…Table summarizes these results and shows the positions of the Nd 3+ 4 I 9/2 → 2 P 1/2 transition fitted for amorphous materials with R = 0, 0.25, and 0.75 which remained at about 23217 cm −1 regardless of La/(La + Nd). According to previous investigations, the energy position for Nd 3+ occurs at about 23260, 23240, and 23225 cm −1 in aluminosilicate, borate, and silicate environments, respectively . It is therefore reasonable to ascribe the transitions found at 23217 cm −1 to Nd 3+ cations surrounded by silicate tetrahedra.…”

Spectroscopic Investigation and Crystallization Study of Rare Earth Metaborate Glasses

“…3g) and is displaced towards higher energies (23,332 cm -1 instead of 23,275 cm -1 for the glass). This latter observation can be related to a decrease of the covalence of the average Nd-O bond (nephelauxetic effect, Gatterer et al, (1998), Quintas et al, (2008), Majérus et al, (2011)) compared with the glass and thus to an increase of the distance between Nd 3+ ions and oxygen atoms in the crystal.…”

“…Such nuclear waste is then generally stored in complex borosilicate glassy matrices, where RE ions seem to interact more specifically with the boron (Majérus et al, 2011), B 2 O 3 being used in these glasses as a flux agent and to decrease the melting temperature. Indeed, it has been observed that adding boron oxide tends to decrease the crystallization tendency of a RE-rich apatite phase in RE-bearing borosilicate glasses.…”

“…The structure of this crystalline phase ( Fig. 1) consists in ladder-type chains composed of BO 3 trigonal and BO 4 tetragonal units in a 2:1 ratio and are interconnected by RE 3+ ions that are coordinated by ten oxygen atoms (Pakhomov et al (1969), Ysker et al (1970), Müller-Bunz et al (2003). In this structure, three types of oxygen atoms can be distinguished: two of them being bridging oxygen atoms (BO) connecting BO 3 and BO 4 units and the third one being a non-bridging oxygen atom (NBO), carried by the BO 3 units.…”

Comparative study of the rare earth environment in rare earth metaborate glass (REB 3 O 6 , RE = La, Nd) and in sodium borate glasses

“…A high amount of RE oxides is also found in nuclear glasses, because RE are abundant fission products (about 4 wt.% in R7T7). In addition to its effect on melt properties, boron oxide enhances the thermal stability and waste incorporation level of aluminoborosilicate waste glasses [6][7][8][9], notably by increasing the solubility of RE. Thus, due to their occurrence in optical materials and in nuclear waste glasses, it is interesting to investigate the structure of RE-bearing borate glasses, and in particular the RE environment because it is related to the optical properties of the rare earth center (transition rates, branching ratio, quantum efficiency) and to the thermal stability of the material.…”