The hydrometallurgy
Hydrometallurgical techniques gather together all techniques aimed at extracting a metal or a metallic compound, from a material through dissolving operations, solution purification, precipitation and the separation of solid and liquid phases. More generally, they can also be applied to the extraction and production of non-metallic compounds. The choice of techniques employed and the operational conditions depend on technico-economic and also environmental criteria. Dissolution can be performed in an acid medium or a base medium. The choice of acid or base used depends on the nature of the elements to be extracted, as well as on subsequent operations. The use of oxidising or reducing agents can improve the result or the selectivity of the extraction, depending on the case at hand. Solution bearing metals can be precipitated, more or less selectively, through acid-base reaction, oxido-reduction (electrodeposition, cementation, etc.) or the formation of insoluble compounds (sulphides, sulphates, phosphates, etc.).
They are then collected through the separation of liquid and solid phases. Research into specific properties for finished products, new requirements in terms of purity, the increasing complexity of materials processed and environmental constraints have all been factors behind the development of hydro-metallurgy in recent decades. Thanks to its expertise in this field, CTP is able to study, propose, optimise or simply assess hydro-metallurgical procedures through tests conducted within various scenarios, either at laboratory scale (reactors and autoclaves) or in its pilot station. This latter has a number of lines of leaching reactors in series (~20 litres/reactor) with heating methods (steaming) along with filters (filter press, band filter, drum filter).
