ИСТИНА

The kinetics of aqueous leaching of tantalum from the sintered semi-product of complex processing of rhenium-nickel superalloy waste was investigated. The intermediate product was sintered with potassium hydroxide at 800 °C, followed by aqueous leaching of the sinter. It was established that increasing the temperature accelerates the leaching process: the maximum rate was achieved at 90 °C. The kinetic curves were analyzed using the Prout-Tompkins, Jander, and Ginstling- Brounshtein models. The Ginstling-Brounshtein model showed the best fit to the experimental data, indicating that internal diffusion is the rate-limiting step. The calculation of the apparent activation energy also confirmed internal diffusion as the process-limiting mechanism.