Cashew nuts are shelled through both manual and mechanical processes, primarily to remove the caustic cashew nutshell liquid (CNSL) present between the outer shell and the kernel.
Manual Shelling
- Process: Workers use wooden mallets and pieces of bent wire to crack open the shells.
- Drawbacks: This method poses significant risks, as the CNSL can cause severe burning rashes and eye irritation to workers. Precautions like gloves and eye protection are necessary, but not always adequately provided.
Mechanical Shelling
- Process: Cashew nut shelling machines automate the process. These machines are designed to crack the shells open efficiently while minimizing damage to the kernel.
- Advantages: Mechanical shelling reduces the risk of exposure to CNSL and increases processing efficiency. Various designs exist, from simple hand-operated machines to fully automated systems.
Cashew Nut Shell Liquid (CNSL) Handling
Regardless of the shelling method, careful handling of the CNSL is crucial. The urushiols present in CNSL are toxic and require special treatment. The extracted CNSL is a valuable byproduct used in various industrial applications, such as resins, friction linings, and surface coatings.
