Influence of increased temperature from cement hydration on aluminum corrosion prevention when LiNO3 is added to the cement

The influence of increased temperature from cement hydration was checked on aluminum corrosion prevention when LiNO3 was added to the cement used for aluminum waste cementation. At first, the temperature at the center of a 0.2-m(3) cement or mortar form was measured. Then, because the reaction mechanism of LiNO3 involves forma tion of insoluble LiH 2AlO(2) 5H(2)O (Li-Al) presentation film on an alumin um surface, the Li-Al film solubility was measured in a 0.1 M KOH aqueous s olution at temperatures from 283 to 353 K. In a second experiment, an alumi num specimen was soaked in a 0.1 M KOH solution with 3 wt% of dissolved LiN O3, and the volume of generated hydrogen gas was measured. Finally, aluminu m plates were solidified with mortar in a full-scale test. The mortar mixtu re contained ordinary portland cement (OPC), blast furnace slag (BFS), and sand with a 1.5 wt% LiNO3 addition, and the volume of generated hydrogen ga s was measured. When only OPC was used, the temperature increased to similar to 363 K. With the BFS and sand addition, this temperature increase was reduced by simila r to 40 to 323 K The Li-Al film solubility became larger as the temperature of the solution increased The volume of hydrogen gas generation became lar ge as the temperature increased, especially ol er 323 K, When the mortar co nsisted of OPC, BFS, sand, and LiNO3, the volume of hydrogen gas generation from aluminum was reduced, becoming <10% of that without the LiNO3 additio n, Thus, it appears that the temperature did not have much influence on the ability of LiNO3 to prevent aluminum corrosion, although the ability was g radually lessened as the temperature increased.