Closed loop
Recovery of acid allows wastewater treatment to be cut by up to 90 percent

An important step of industrial processes is the reprocessing of used acids and water with a view to recovering the acid contained in them. Such a recovery allows wastewater treatment to be cut by up to 90 percent. This clearly means substantially less environmental pollution and a corresponding reduction in costs, as less acid - the raw material required for the process - needs to be purchased.
With its long-standing tradition dating back to 1834, the F.X. Nachtmann Company ranks among the leading manufacturers of lead crystal and crystal glass. An important process in the lead-crystal manufacturing business is chemical mirror finishing, which takes after the glass has been diamond ground. The process uses a mixture of sulfuric acid (65 weight percent) and hydrofluoric acid (1.5 weight percent). Chemical machining not only leads to defined substrate surfaces but also has a positive influence on the corrosion resistance of the glass. Acid polishing is a multi-stage process, with a two-step pretreatment (cleaning, degreasing) followed by the actual polishing in a polishing bath. Subsequently, the glasses are washed in a three-stage rinsing cascade.