Bipolar Membrane Electrodialysis for Sulfate Recycling in the Metallurgical Industries

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-09-18
Major/Subject
Mcode
Degree programme
Language
en
Pages
13
718-730
Series
MEMBRANES, Volume 11, issue 9
Abstract
Demand for nickel and cobalt sulfate is expected to increase due to the rapidly growing Li-battery industry needed for the electrification of automobiles. This has led to an increase in the production of sodium sulfate as a waste effluent that needs to be processed to meet discharge guidelines. Using bipolar membrane electrodialysis (BPED), acids and bases can be effectively produced from corresponding salts found in these waste effluents. However, the efficiency and environmental sustainability of the overall BPED process depends upon several factors, including the properties of the ion exchange membranes employed, effluent type, and temperature which affects the viscosity and conductivity of feed effluent, and the overpotentials. This work focuses on the recycling of Na2SO4 rich waste effluent, through a feed and bleed BPED process. A high ion-exchange capacity and ionic conductivity with excellent stability up to 41 degrees C is observed during the proposed BPED process, with this temperature increase also leading to improved current efficiency. Five and ten repeating units were tested to determine the effect on BPED stack performance, as well as the effect of temperature and current density on the stack voltage and current efficiency. Furthermore, the concentration and maximum purity (>96.5%) of the products were determined. Using the experimental data, both the capital expense (CAPEX) and operating expense (OPEX) for a theoretical plant capacity of 100 m(3) h(-1) of Na2SO4 at 110 g L-1 was calculated, yielding CAPEX values of 20 M EUR, and OPEX at 14.2 M EUR/year with a payback time of 11 years, however, the payback time is sensitive to chemical and electricity prices.
Description
This work has received funding from the European Institute of Innovation and Technology (EIT), a body of the European Union, under the Horizon 2020, the EU Framework Programme for Research and Innovation. Project Name and Number: Credit -18243. SUEZ Water Technologies and Solutions is acknowledged for the supply of the membranes.
Keywords
bipolar membranes, electrodialysis, ion-exchange membranes, sodium sulphate, Sodium hydroxide, sulfuric acid, electrotransport
Other note
Citation
Kuldeep, K, Badenhorst, W, Kauranen, P, Pajari, H, Ruismäki, R, Mannela, P & Murtomäki, L 2021, ' Bipolar Membrane Electrodialysis for Sulfate Recycling in the Metallurgical Industries ', Membranes, vol. 11, no. 9, 718 . https://doi.org/10.3390/membranes11090718