Search results for "Pickling solution"
showing 4 items of 4 documents
Metals Recovery from Waste Pickling Solutions by Reactive Precipitation
2021
Pickling is one of the most important steps in steel manufacturing industry. During the process, an acid reacts with the surface oxides causing metal ions accumulation in the pickling solution. Disposal of the waste acid represents a critical issue for the hot-dip galvanizing industry in terms of environmental damage and high costs. Recovering of the main products by using an integrated process, with the perspective of a circular approach, could minimize the wastewater production, leading to reinvigorate this industrial sector economy. In this context, recovery of the metal ions mainly present in the pickling solution, such as Fe and Zn, becomes a critical issue. In this work, the reactive …
Effective recovery of HCl and metals from pickling solutions by cutting-edge membrane technologies
2018
The pickling process is an essential step in the hot-dip galvanizing process.It is performed by immersing manufacturedsteel pieces inacid bathsin order todissolve the oxidized layers. During the pickling process, acid attacks metal oxides on the surface, dissolving them in the pickling bath. Thus, the efficiency of the pickling liquor decreases due to the accumulation of metal salts and the consumption of free acid in the solution. When hydrochloric acid is used,ferrous chloride is producedduring the pickling treatment, reaching concentrations up to 250 g/l, while the acid concentration decreases by 75-85%. A pickling bath in this condition is considered spent [1] due to thevery low picklin…
Experimental investigation and modelling of diffusion dialysis process for regeneration of acidic pickling solutions
2017
Pickling is one of the key steps in metal finishing industries, where HCl solutions are largely used thus generating significant amounts of spent waste solutions containing high concentrations of metals and acid. The recovery of acid from such waste solutions is thus one of the most beneficial steps for reducing the environmental and economical impact of these processes. Among several separation methods, diffusion dialysis (DD) is becoming more and more attractive thanks to the recent important advances in ion exchange membranes (IEMs) field and because of its clean nature and operational simplicity, low installation and operating costs and low energy consumption [1,2]. In the present work,…
Experimental investigation and modelling of diffusion dialysis for the recovery of waste acid solutions
2018
Pickling is widely used as a chemical pre-treatment method for cleaning metal surfaces before other surface treatments and it consumes large amount of acids and water