Pickling of stainless steel causes environmental problems for our ecosystem and generates high operational costs for stainless steel producers. In stainless steel pickling, parts of the acids are reacting with the steel surface and are transformed to chromium, nickel and iron salts. Globally more than 350,000 liters of mixtures of these acids are being used for stainless steel pickling processes every hour and turned in large amounts of waste acid. Disposal of spent acid causes significant environmental problems and endangers today’s stainless steel pickling operational licenses.
Before the waste acid can be discharged into the environment, it is typically diluted with water and neutralized with Ca(OH)2 forming calcium fluorides and calcium nitrates as well as metal hydroxides. The fluorides and the hydroxides precipitate and can be separated through a filtration process. As a result, toxic sludge and nitrate-containing wastewater is generated. The sludge needs to be transported to a landfill for hazardous waste. Depending on the environmental limits, the nitrate-containing wastewater needs to be processed further in a wastewater treatment plant or can be directly disposed into the environment.
With the REGMAX® technology, this is no longer an issue. For the first time ever, it is possible to transform all waste acid components into valuable resources - creating a closed loop of resources. By implementing REGMAX® technology, it is not only making the world a better one, but also reducing pickling costs. Neither sludge nor wastewater is generated and no DeNOx unit is needed. Recovery rates are >99% for HF and >98% for HNO3.