Kinetic Study of the Extraction of the Osmium (VI) Sulfite Complex by Tri-Octylamine from Sulfurous Solutions

To develop effective technologies for extracting osmium from solutions obtained in the process of processing intermediate products of copper production, their intensification, selection of equipment, it is necessary to know the kinetic parameters of the extraction process. However, there are no data on the kinetics of osmium extraction with amines from sulfate solutions. For the first time, kinetic regularities of the extraction of the osmium (VI) sulfite complex [OsO2(SO3)2(H2O)2]2- from sulfuric acid solutions with tri-octylamine (T & Ocy;A) [Alamine 336] were revealed using a Lewis diffusion cell. To clarify the mechanism of extraction of the osmium (VI) sulfite complex from sulfurous solutions, one of the necessary conditions is to determine the type of equation for the kinetics of the extraction reaction, the values of its parameters and an assessment of the region of its occurrence. The apparent extraction rate constant is (4.60 +/- 0.18)center dot 10-6 m center dot s-1. Orders were established for the reacting components: the interaction of TOA with the sulfite complex [OsO2(SO3)2(H2O)2]2- proceeds according to the reactions of the first order with respect to the metal and the second order with respect to the extractant. The value of the apparent activation energy 29 kJ/mol was determined. The process is performed in the diffusion-kinetic region and is limited by mass transfer through the interfacial area. The composition of the extractable complex was determined by the dilution method. The compound was isolated in an individual state, studied by the elemental chemical method, UV- and IR-spectroscopy, and its composition was installed: (& Tcy;& Ocy;& Acy;& Ncy;)2[OsO2(SO3)2(H2O)2].