More than 50 percent of the input polysilicon feedstock are lost during PV production. Deposition of these wastes in landfill has a negative environmental impact and means that the high energy invested in the production of virgin silicon is lost. Up to now, cost efficient and safe recycling methods for Si-kerf do not exist.

Novel technology to recycle and manufacture low-cost silicon metal powders from waste and deposited materials, leading to metallurgical grade silicon. The novel technology developed by RESITEC for recycling of silicon kerf from diamond wire cutting processes is cost efficient and results in silicon powders with 1-5μm as D-50, 2-4 N (which means 99,00% to 99,99%) purity, low oxidation levels of 1-4% and low boron and phosphorus content. Silicon kerf can be recycled into fine powders or agglomerated to reduce dusting and dust explosion hazards, the agglomerated material is suitable for melting in furnaces.

What is new?

• First technology for silicon kerf recycling with an industrial high yield process.
• Providing silicon powders with a significantly reduced carbon footprint.
• Recycling process without melting steps, built on unit operations with separation of particles, chemical treatment, filtration of fine particles, drying and classification of particles.
• Unit operations can be combined and closely adapted to different industrial cutting process.
• Passivation of the surface of the silicon particles to avoid oxidation directly on site.