When lithium-ion batteries are processed using the wrong recycling technology, fires often occur. A new, gas-tight process from BHS-Sonthofen circumvents these dangers. In this process, the lithium-ion batteries are first fed into the process manually via a hopper. Via two electric sliders, the batteries pass to a single-shaft shredder from BHS, the universal shredder (type NGU). This process is blanketed with nitrogen from the start to prevent explosions. A screw conveyor takes the shredded material to the AVA-HTC dryer from BHS, which operates in batches, to separate the hazardous electrolytes.
The dryer applies a vacuum and slowly heats the feed material. The gases escape via a vapor filter; this is followed by two condensation units: a shell-and-tube heat exchanger and a plate heat exchanger separate the electrolytes. To neutralize harmful acids in the exhaust air, it is passed through a grease bed reactor filled with milk of lime. A downstream activated carbon filter removes aromatized hydrocarbons from the exhaust air. The gas stream thus purified meets all legal requirements.
After drying, the crushed batteries no longer pose any danger. All remaining solid components leave the gas-tight area and undergo a dry mechanical sorting process. In this process, the fine black mass is first screened off. A zigzag sifter sorts the larger components into light and heavy fractions. The heavy fraction mainly contains coarse metal parts, which can be separated into ferrous and non-ferrous fractions by means of an eddy current separator and overband magnet. The light fraction passes via a carrier film to a turbo mill and is finally separated into the finished metal concentrates via a screen.
BHS designed the recycling plant including an in-house intelligent control solution from its subsidiary BHS Control Systems. Recipe control systems were used to precisely define the process described. BHS thus implemented an integrated overall solution comprising process, technology, and control engineering that integrates all process elements. The customer has been highly satisfied with the solution since the start of production.