Nitrate and nitrite incompatibility with hydroxide ions in concentrated NaOH solutions: Implications for hydroxide and gibbsite reactivity in alkaline nuclear waste

Electrolyte solutions in alkaline nuclear waste contain aluminate, hydroxide, nitrate and nitrite with sodium as the predominant counterion. The salts of these ions are highly soluble, so liquids concentrated. This study found that there is a substantial incompatibility between hydroxide and/or ions. was determined by observation adding just one molal NaNO2 or NaNO3 to saturated NaOH solution results precipitation 10 mol NaOH•H2O salt, whereas common ion effect only about 1 mole would have been expected precipitate. Further analysis indicates presence drastically increases reactivity solution, which likely influences other hydroxide-mediated reactions. enhanced due disruption large Na+-OH− networks, because do not fit into those similar way certain substitution foreign crystal lattice. In contrast, aluminate did same hydroxide.