Thermal properties and crystallization kinetics of a sodium aluminophosphate based glass

The structure of aluminophosphate glasses revisited: Application of modern solid state NMR strategies to determine structural motifs on intermediate length scales

“…Mixtures of appropriate amounts of reagent grade K 2 CO 3 , Al(OH) 3 and (NH 4 ) 2 HPO 4 (to obtain 10 g of glass) were heated slowly to 600°C (1°/min) in an electric furnace to remove H 2 O, NH 3 and CO 2 . The batch was then directly melted in a Pt crucible during 20 min, before being quenched between two copper plates to obtain colorless and transparent glasses.…”

“…Phosphate based glasses are involved in a wide variety of technological applications including biomaterials [1], sealing glasses [2], anti-oxidation coatings or as confining matrices for nuclear waste material [3], all of which benefit from the low glass transition temperature (T g ) values or from the high thermal expansion coefficient of the phosphate network. However, pure phosphate glasses suffer from a poor chemical durability which severely impedes their straightforward application.…”

Immobilization of simulated radioactive fluoride waste in phosphate glass

“…In addition, the low structure quality may be related to the existence of Q 3 units, where three of the oxygens are bridging (P-O-P) and one is non-bridging (P=O). P-O-P is easily hydrolyzed, and results in the depolymerization of the glass network upon hydration through the formation of a terminal -OH group [8,32]. When CaO was added to the NaAlP matrix, the quantity of released Na and K decreased in an obvious manner, but Sr and P increased dramatically.…”

A review on immobilization of phosphate containing high level nuclear wastes within glass matrix – Present status and future challenges

“…Parallel to this, Kushinikov et al [92] and Matyunin and Jardine [93] tried to immobilize Pu rich waste, both in the form of PuO 2 powder and Pu nitrate solution, within Na Al phosphate glass (Na 2 O: 24 wt%, Al 2 O 3 : 22 wt% and P 2 O 5 : 54 wt%) and respectively could load 0.24-0.31 wt% (for PuO 2 powder waste) and 0.7-0.8 wt% (for Pu nitrate waste) of waste homogeneously. Lately, Donald et al [94] considered Na Al phosphate glasses (41.0Na 2 O-20.5Al 2 O 3 -38.5P 2 O 5 (mol%)) for encapsulating Ca phosphate ceramic (containing chlorapatite (Ca 5 (PO 4 ) 3 Cl) and spodiosite (Ca 2 (PO 4 )Cl)) loaded with chloride enriched HLWs [95]. They studied the devitrification tendency of the encapsulating glass (AlPO 4 , Na 3 PO 4 , NaAlP 2 O 7 and Na 7 (AlP 2 O 7 ) 4 PO 4 ) and hardly found any detrimental effect of the same on the overall properties of the final monolithic wasteform.…”

“…Toward this a number of efforts have been made across the world over the last fifty years, but so far limited progresses have been made to produce such matrices in actual plant scale on regular basis. The probable reason behind this is lack of complete comprehensions of the problem, its 79 Se, 85 Kr, 87 Rb, 89 Sr, 90 Sr, 93 Zr, 95 Zr, 95 Nb 99 Tc, 107 Pd, 115 In, 126 Sn, 129 I, 131 I 135 Cs, 137 Cs, 141 Ce, 142 Ce, 144 Ce, 144 133 Xe, 140 Ba, 134 Te, 93 Mo, 106 Ru, 106 Rh, 107 Pd, 140 La, 154 Eu Activation products 3 H, 10 Be, 14 C, 24 Na, 36 Cl, 39 Ar, 55 Fe, 59 Ni, 60 Co, 63 Ni, 93 Mo, 93m Nb, 94 Nb, 99 Tc, 108m Ag, 113m Cd, 121m Sn, 205 Pb, 210 Po associated difficulties and bottle neck situations. Hence for better understanding of the subject and to take right steps towards feasible solutions it is absolutely necessary to put together the lessons we have learnt from past experiments.…”