Gongye shui chuli (Mar 2024)
Study of mine concentrated brine water treatment technology based on bipolar membrane electrodialysis
Abstract
The bipolar membrane electrodialysis（BMED） process can transform the concentrated brine produced by the mine water membrane concentration system into acid and alkali，so as to realize the resource treatment of concentrated brine. The operating energy consumption of BMED is high，and its treatment performance is closely related to the initial acid/base concentrations，electrolyte concentration and current density of the system. So，it is necessary to study and optimize the operating parameters to reduce the operating cost of the system. In this paper，nanofiltration（NF） concentrated brine and disctube reverse osmosis（DTRO） concentrated brine produced by a zero discharge treatment system of mine water as research objects，the operating voltage，initial acid/base concentrations and current efficiency of the BMED were studied by using a bipolar membrane electrodialysis pilot system under different initial acid/base concentrations，electrolyte mass fractions and current densities. The experimental results showed that，for the treatment of concentrated saline，when the initial acid/base concentration was about 0.1 mol/L，the acid/base concentration produced by BMED was the highest. The rates of acid/alkali production in BMED devices was related to the electrolyte mass fraction，and the acid/alkali concentration increased rapidly under low electrolyte mass fraction conditions. In addition，the speed of acid and base generation in the BMED was positively correlated with the current density，while the current efficiency was negatively correlated with the current density. For the treatment of NF concentrated brine，the highest economic efficiency was achieved when the initial acid and base concentrations were both about 0.1 mol/L and the current density was controlled at 21 mA/cm2. In addition，according to the operation parameters of the BMED，the cost and benefit of the concentrated brine resource treatment were calculated. The results showed that the operation cost of the BMED process for NF concentrated brine was lower than that of the DTRO-evaporation crystallization process，and it was economically feasible.
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