GERRI develops new processes to recover or eject metals from materials. This reaches from classical ore processing up to recycling of modern end of life products and everything in-between. Therefore a large variety of unit operations is needed and used. Different milling types, screening and sorting technologies (e.g. magnetic separation, flotation) with different physical and technological backgrounds are in our technical centers. The scale goes from lab scale up to small and large pilot scale. The classical processing unit operations are rounded up with modern equipment as well as chemical and biological processing technics.




Characterization of materials covers different fundamental processes to probe and measure material structures and properties.

  • Cerchar abrasivity test
  • Granulometric analysis
  • Shear tests, flowability tests, silo design




Comminution processes are used to adjust the grain size distribution, to liberate valuable materials or to effect the material itself. A large variety of machinery, modern and classic are available for testing.

  • Crushing, grinding, milling
  • Electrohydraulic fragmentation
  • Reaction milling
  • Selective comminution
  • Grindability tests, process design




Classification describes methods to separate materials depending on grain size. Hereby different techniques like screen sizing or air and hydraulic classification are used.

  • Screen sizing




Different physical properties of materials like density, conductivity, magnetical properties are used in sorting technologies to split different materials from each other. These can be used in processes to enrich or decrease the content of specific materials in specific fractions.

  • Magnetic separation
  • Gravity separation (dry)
  • Gravity separation (wet)
  • Eddy current separation
  • Froth flotation
  • Bioflotation




Solid-Liquid-Separation is a separation process based on different physical states (solid, liquid). The separation of the two phases is carried out by filtration and membrane techniques.

  • Filtration, centrifugation, dynamic membrane filtration


Specific Processing


Specific Processing describes physical methods for materials processing such as thermal pre-treatment or sensor-based sorting using specific or customized technologies. It also includes optimization of common technologies.

  • Development and optimization of mineral processing designs
  • Thermal pre-treatment, fine grinding and benefication, sensor-based pre-concentration




Agglomeration is used to influence the grain size of substances, e.g. dusts or sands, for better transport or subsequent usage e.g. in furnaces.

  • Pelletising