(726c) Study of the Physicochemical Properties, the Aging Phenomena, and the Production Method of an Extinguishing Powder for Sodium Fire

The French Atomic and alternatives Energy Commission (CEA) developed an effective powder capable of extinguishing sodium fire. It is a powder based on a mixture of lithium carbonate and low-hydrated sodium carbonate in a near eutectic proportion, with a melting temperature around 500°C, associated with graphite. However, ever since the dismantling of several old sodium installations facilities, CEA has at its disposal an important stock of unused powder batches. The idea of reutilizing these powders initiates the question about their efficiency to extinguish a sodium fire after long term storage. This study proposed the physicochemical analyses of these powders in order to identify their compositions and characteristics for different batches. The results highlight the presence of lithium sodium carbonate (LiNaCO₃) and trôna (Na₂CO₃.NaHCO₃.2H₂O). The aging experiments were developed to study the role of moisture and ambient carbon dioxide during the storage. The results showed that LiNaCO₃ is sensitive to the presence of moisture, able to transform it into lithium carbonate and sodium carbonate monohydrate, meanwhile the latter reacts with water and carbon dioxide to form trôna. Finally, a study of the formation of LiNaCO₃ allowed the understanding of the fabrication method of the powder.