Chemical News

Monday, August 11, 2008

Recovery of Acids & Salts from Pickling liquor

Steel fabrication processes often use pickling (immersing steel in acid) to remove oxide layers from recently heated steel. Technology for recycling the sulfuric acid has been available for large installations for some time. The Green Technology Group, in collaboration with DOE’s Inventions and Innovation Program, developed the Pickliq® process to make sulfuric acid recovery cost-effective for smaller facilities.



The Pickliq process combines diffusion dialysis, energy transfer, and low-temperature crystallization technologies to efficiently recover acids and metal salts. It has demonstrated significant gains in production capacity, quality control, and productivity by maintaining pickling tank acid and iron concentrations at preset levels.

Bath uniformity and predictable performance raises output and minimizes rejects and rework. To manufacturers, these benefits are even more important than the simple cost savings from eliminating waste. Additional benefits include reduced demand for virgin acids and elimination of chemicals to neutralize waste acid, as well as energy and cost savings associated with acid transportation and disposal.

The Green Technology Group has recently improved the technology, and the new system called Pickliq Hydrochloric Acid Regeneration (PHAR®) will soon be commercially available.

Benefits
  • Continuous Process
  • Recovery of HCl, H2SO4, HF, HNO3
  • Recovery of metal salts in saleable form
  • Energy Saving
  • Overall Cost reduction

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