Static purification-concentration process:: study of the system manganese, sulfuric acid-tri-n-octylamine

In the frame of a global process of marginal ores treatment and of the treatment of solid residues containing heavy metals, we can associate the techniques of static solid-liquid extraction to the techniques of static liquid-liquid extraction. The static solid-liquid extraction or leaching is now well known in the processing of small-content ores. It could be easily used to abstract the lixiviable fraction of the residues and contribute to their inerting. It only remained the setting of systems of treatment of leaching solutions suitable with solid-liquid extraction from the kinetic, technological and economic point of view. For this doing we have developed a static liquid-liquid extraction technique associating extraction to re-extraction. A static purification-concentration process has been devised thanks to a liquid-liquid extraction-re-extraction reactor where the extraction compartment and the re-extraction compartment are put in contact with one another through the organic phase composed of ail extractant and a diluent. We have applied this process to the system: manganese (Mn), sulfuric acid-tri-n-octylamine. Interesting performances have been realized for diluted solutions (100 ppm). A chemical modelization has allowed to identify the extraction mechanisms. The classical behaviour obtained in agitated surroundings has been found again. A physical modelization has allowed to demonstrate the existence of transfers which find their origins on the one hand, in a chemical potential gradient and on the other hand, in the transports related to concentration gradients.