GERRI develops and optimizes hydrometallurgical methods and processes for extraction, refining and recycling of metals. Our main competences are in the fields of electrolysis procedures, leaching and ion selective processes like solvent extraction, membrane techniques and ion exchange. The activities in the field of electrolysis comprise the development and optimization of methods for electrowinning and electrorefining of metals, electrochemical procedures to separate metals from solutions as well as waste water treatment. Leaching (atmospheric and high-pressure and bioleaching) offers various prospects to extract metals from primary and secondary raw materials by means of liquid media or microorganisms. Solvent extraction and membrane processes (diffusion dialysis, electrodialysis, nano- and ultrafiltration) are well proven possibilities to separate and enrich metals from metallurgical solutions and waste water. Many years of experience of the GERRI partners in the above mentioned areas provide a good basis to solve complex problems. A comprehensive range of equipment enables the realization of test experiments and systematic investigations.


Electrowinning and electrorefining


This field of competence comprises the development and optimization of electrolysis processes for electrowinning and electrorefining of metals. It includes the development of new electrolyte and additive systems and for an improved cathodic deposition of metals in metallurgy and electroplating. The electrochemical winning of metals from metallurgical process solutions and the electrochemical treatment of wastewater are part of this domain, too. Moreover new anode materials for the electrowinning of metals (e. g. lead alloy anodes) are developed. A wide experience exists especially for electrolysis processes with copper, zinc, tin, lead, silver and indium.

  • Electrowinning and electrorefining of metals


Ion selective processes


Different methods in this field provide a separation of metals from process solutions and waste water and/or the concentration of metals.

  • Diffusion-/electrodialysis
  • Ion-exchanger
  • Solvent extraction
  • Ultra-/nanofiltration




Leaching aims at the selective dissolution of one or more compounds of a solid mixture. Either the dissolution of value materials or the selective removal of impurities from the solid can be realized with this process. An optimal leaching process can be ensured by variation of the operating parameters (grain size of the solid, chemical composition and concentration of the solution, solid liquid ratio, temperature, stirring conditions …).

  • Atmospheric leaching
  • Pressure leaching


Special separation processes


Those processes deal with the development of innovative biotechnical and biohydrometallurgical processes for the recovery and extraction of metals.

  • Bioleaching
  • Biosorption