Hydrothermal metallurgy: An overview of basic concepts and applications

Innovation in process technology as applied to extractive metallurgy may enable mining companies to combine profitability and improvements in environmental management. One of the ideas in process innovation is the use of hydrothermal conditions, hence the term hydrothermal metallurgy. Hydrothermal metallurgy is defined here a process which involves hydrothermal synthesis for recovery of metals or inorganic compounds. The reactions are carried out in a high pressure reactor, in which raw materials or residues intermediate products are processed into high quality and, therefore, marketable products. The reaction conditions are such that the temperature in the reactor always corresponds with the saturated steam pressure. This paper discusses the characteristics and merits of this technology, which could reduce operating costs by using a direct process and also mitigate against the adverse environmental impact of some extractive metallurgical processes. It provides an overview of the current state of the art, and additionally highlight some of the yet to be explored research areas.