Press release from February, 15th, 2017
An application case for T-CUT tubular modules: recycling of pickling acids
A huge quantity of pickling acid is accumulated in an international operating association of steel rolling mills every year. Depending on the type of steel, hydrochloric or sulphuric acid is used in weight concentrations of 10 -20 %. In case of non-alloyed steels mixtures with small amounts of nitric acid are applied as well. The acid treatment is combined with mechanical cleaning methods (e.g. brushing) for an optimum result, whereby a particle loaded acid mixture is produced as waste. The waste acids must be neutralized before being discharged into a wastewater treatment plant. Further costs arise from deposing of the sludge resulting from this process.
Processing and recycling pickling acids means an essential measure to reduce costs for chemicals, fresh water and waste disposal and significantly contributes to environmental protection and sustainability in metal processing.
With cross-flow microfiltration, suspended particles can be removed from the pickling acid effectively. The filtrate is recycled into the process – after additional cleaning steps, if necessary. Due to their high resistance against acids, caustics, and abrasive metal particles, T-CUT tubular modules by CUT are particularly suitable for this application. The symmetric tubular membranes from polypropylene offer outstanding resistance against abrasion as well as mechanical and chemical stability.
Microfiltration of pickling acids enables the contaminated liquid to be concentrated to a factor of up to 5, which means a reduction of waste volume to the same amount. The remaining concentrate contains up to 35-40 % solids. Operational temperature is up to 40 °C, and the pH value may fall below zero.
T-CUT PP modules ensure a stable permeate flux of about 80 l/(m2h). The filtration performance is maintained high by backflushing the symmetric membranes for a few seconds every 30 minutes. Despite the massive mechanical and chemical load the modules achieve a service life that clearly exceeds 2 years. Thus an economically end ecologically-sound treatment process can be implemented.
Information about the company:
CUT Membrane Technology a part of the Bürkert Group since beginning of 2013, produces innovative membranes and modules in Erkrath, Germany , including tubular, hollow fibre and polypropylene based filtration modules for separating liquid media. CUT supports their customers with application and process expertise in the chemical, food and environmental technology industries, especially with regard to the treatment of process and waste water.
For further information contact:
Tel: +49 (0) 6196/653211