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AssigneeEvonik Operations GmbH
InventorsChristian Hying, Elisabeth Gorman, Meike Dahlhues, Nicole Decker, Patrik Stenner, Tobias Stadtmüller, Sebastian Arndt
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The invention relates to the operation of an electrochemical cell (0) for the purpose of processing lithium-containing waters. It is based on the object of operating the cell (0) with better current yield in order to keep its permeance constant and to improve the purity of the target product (LiOH). An essential aspect of the process according to the invention is that it is carried out in a three-chamber cell having an anode separator (3) and a cathode separator (4). A basic idea of the process according to the invention is to use an inorganic cathode separator (4) having an ion selectivity in favour of lithium. This has the result that fewer cationic impurities (Mem+) are able to be converted into unwanted byproducts, which increases the current yield and improves the purity of the target product (LiOH). The anode separator (2) is anion-conducting. A further, essential aspect of the operation according to the invention is that two electrochemical processes are carried out simultaneously, namely on the one hand a membrane-supported electrodialysis of ions and on the other hand an electrolysis of water.
Process for operating an electrochemical cell, comprising the following, non-chronological steps:
Process according to any of the preceding claims, where the inorganic material present in the cathode separator has a specific conductivity for Li cations σ, measured by the “impedance spectroscopy” method described herein, that at a temperature of 23° C. is at least 1*10−5 S/cm or at least 5*10−5 S/cm or at least 10*10−5 S/cm and at most 100*10−5 S/cm.
Dependencies are inferred from the claim text.