Crystalfix is the most updated technology for the recovery of caustic soda used in the process of dies pickling by the aluminium extrusion industry. The caustic soda recovery process consists of a closed loop connected to the die-cleaning system. The loop is made of a regeneration module with a filtration system. In this way, the caustic soda is completely recovered. The advantages connected with the use of Crystalfix are many, and involve all the aspects of dies pickling technology, from saving of caustic soda to saving for non-disposal of spent solutions, from easiness of process to minimizing storage and transport of chemicals, till an environmentally friendly approach for dies cleaning.