Search results for "hydrochloric acid recovery"
showing 5 items of 5 documents
Modeling and Design of Membrane Integrated Processes for HCl and Metals Recovery from Pickling Solutions
2018
Hydrochloric acid pickling is a common practice in steel manufacturing industry. During the process, acid is consumed to dissolve surface oxides and metals are accumulated in the solution. This fact leads to a process efficiency decrease. Continuous regeneration of pickling solutions enhances process rate and performance, but also minimises the highly expensive and environmentally risky wastewater disposal. The recovery of valuable substances (e.g. acid and metals) can be accomplished by coupling diffusion dialysis (DD) and membrane distillation (MD) technologies. In the present work, a steady state process simulator for the integrated process has been developed. The aim is to analyze and p…
Modeling and Design of Membrane Process Recovery of HCl and Metals from Pickling Solutions
2018
Abstract Hydrochloric acid pickling is one of the key steps in the hot-dip galvanizing process. It is a process widely used as a chemical pre-treatment method for cleaning, where metal surfaces with oxides are immersed into an acid solution. During the pickling process, the acid concentration decreases with time while the metal is accumulated. Thus, the efficiency of the pickling solution decreases and fresh solution must be used. Continuous regeneration of pickling solutions enhances pickling rate and process performance, but also minimises industrial wastewater disposal and chemicals consumption. The recovery and recycling process of valuable substances (e.g. acid and metals) can be accom…
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