Search results for "Acid recovery"
showing 5 items of 15 documents
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…
An integrated approach for HCl and metals recovery from waste pickling solutions: pilot plant design and operations
Continuous regeneration of industrial pickling solutions and recovery of valuable materials are implemented in a pilot-scale plant including diffusion dialysis, membrane distillation and reactive precipitation units. The main results of the preliminary assessment of on site operation are presented. Different hydrochloric acid concentration and metals composition were investigated and the performance of the system were analysed in terms of quality of recovered compounds, energy efficiency and environmental footprint.
Neutralization of acid and base solutions by Reverse Electrodialysis with Bipolar Membranes: a sustainable way to recover energy
2020
The large amount of acidic wastewaters produced in various industrial processes can have a large economic and environmental impact. Companies producing waste acid solutions have to send them to specific sites for the neutralization with alkaline solutions. However, efforts have been devoted so far to promote the acid recovery or its reuse. In the perspective of a more circular manufacturing approach, the present work proposes for the first time the use of the novel Bipolar Membrane Reverse Electrodialysis technology as a viable on-site way to convert the chemical energy associated to the pH gradient of waste acid/base solutions into electrical energy. Bipolar Membrane Reverse Electrodialysi…
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…
AN INTEGRATED APPROACH FOR THE HCl AND METALS RECOVERY FROM WASTE PICKLING SOLUTIONS: PILOT PLANT DESIGN AND OPERATIONS
2020
Pickling is one of the key steps in the hot-dip galvanizing process, where HCl solutions are largely used to remove metal oxides from metallic surfaces, thus generating spent waste liquors containing high concentrations of metals and acid. Disposal of the industrial pickling waste dramatically affects the hot-dip galvanizing industry economics and environmental footprint. Thus, reducing strong acid waste disposal is one of the most beneficial steps to enhance the process sustainability. Moreover, the continuous regeneration of pickling solutions enhances pickling rate and process performance, also minimizing industrial wastewater disposal and chemicals consumption promoting the circular use…