SELFRAG High Voltage Pulse Power Products
SELFRAG AG specialise in the development, engineering and marketing of high voltage pulse power products, plants and systems for selective fragmentation of various solids including composite materials, mineralogical and geological samples.
Founded in 2007, SELFRAG employ a team of high voltage engineers, mechanical engineers and process engineers who are designing and commercialising products and equipment for a range of different applications such as solar, recycling and mining.
SELFRAG have systems suitable for use in laboratories and small pilot plants. They are currently placing significant effort in scaling up their systems to minerals processing levels.
The high voltage pulse methodology used by SELFRAG allows liberation or weakening of a material along natural boundaries. It also enables the controlled fragmentation of a material without contamination through:
- Pulse power technology
- Physical (electrical) materials discontinuities
- High voltage and mechanical engineering expertise
High Voltage Pulse Power
The energy that SELFRAG equipment delivers to the sample can best be likened to a bolt of lightning. Cycling the voltage produces repetitive electrical discharges. The charge is delivered via a process liquid such as water or other dielectric liquid which forces the charges through the material. The electrical energy is transformed into an acoustical shockwave which in turn induces a high tensile stress within the material, which ultimately leads to fragmentation.
High Voltage Pulse Power Fragmentation
Changes in continuity throughout a material via structures such as grain boundaries, defects, or even changes in material (e.g. in composite materials) provide a discontinuity in electrical and acoustic properties.
These discontinuities in the dielectric permittivity enhance the electric field at the grain boundaries, forcing the discharge channels into the grain boundaries. The sudden expansion of the created plasma produces a shockwave with localised pressures of up to 10,000 bar. The combination of the shockwave and the acoustical discontinuity effectively concentrate tensile stresses at these interfaces.
This behaviour induces selective fragmentation and liberates materials along materials boundaries, weakens materials along particle boundaries and reduces particle sizes. Furthermore, as no physical crushing is involved, no contamination is introduced.
Benefits of Selective Fragmentation
The benefits of using SELFRAG high voltage pulse power technology include:
- Increased recovery
- Increase grade
- Decreased energy consumption
- No contamination
- No dust
- Control of target size fraction
- Selective liberation