Exothermic processes in mixtures of TBP with nitric acid

Causes of initiation of exothermic self-accelerating oxidation processes in mixtures of TBP with HNO3 are analyzed. The main condition is heating of the mixtures to temperatures (Т st) above which the heat release in the chemical reaction starts to exceed the heat removal from the system. After the initiation of selfaccelerating exothermic reactions, their development and intensity depend on whether the vessels are sealed, on the HNO3 concentration, and on the heating time. Heat treatment and radiolysis of the extractant slightly decrease Т st of its mixtures with HNO3 compared to the values for the “fresh” extractant.