DPU™ Recovers Phosphoric Acid & Mixed Acids

Eco-Tec offers a system for the purification, recovery, and recycle of various acid mixtures used in the aluminum finishing sector for the brightening, etching, and graining of aluminum product. One such application is the use of phosphoric acid mixtures for the brightening of aluminum in the production of products for automotive and appliance trim, lighting fixtures, bath and shower enclosures.

In North America, the majority of phosphoric acid used in the brightening of aluminum is purified, recovered, and recycled within the processing facility. Eco-Tec has supplied every phosphoric acid recovery system in operation to-date for this purpose.

How It Works:

The Eco-Tec Phosphoric Acid Recovery System consists of two process equipment packages that are integrated into a fully automated system.

Phosphoric acid rinse water (typically 20-35% phosphoric acid) is directed to the first equipment package which is a factory assembled, skid-mounted unit featuring two resin beds piping, valves and controls. This unit (DPU™) combines a cation exchange resin bed with a water elutable resin bed to economically remove dissolved aluminum from the rinse water. The DPU™ uses only about 15% of the sulfuric acid for its regeneration compared with a conventional cation exchanger. The DPU™ can be used to purify other acid mixtures used for the graining (lithographic sector) and etching (capacitor foil sector) of aluminum.

The purified rinse water is then concentrated in a specially designed vacuum evaporator to concentrate the phosphoric acid to 85% for reuse in the brightening bath.

Benefits:

• 85% reduction in phosphoric acid purchases in most aluminum brightening cases.
• Uses an specially designed Vacuum Evaporator for concentrating acid for easy recycle.
• Consistent, predictable bath performance leading to product quality and productivity efficiency gain.
• Significant reduction in waste sludge disposal compared with waste treatment of used phosphoric acid.
• Factory assembled modules and testing in Eco-Tec’s ISO registered facility assures fast start-up and reliable operation.
• Proven, quality, corrosion resistant components and materials selected for long service life in an aluminum processing facility.
• A range of standard systems to provide the most economical package for large capacity aluminum brightening, etching, and graining facilities.
• Uses Eco-Tec’s highly efficient Recoflo® ion exchange process and unique integrated cation exchange/resin sorption (DPU™) process for the greatest acid savings and minimal waste.