Electrolytic production of alkali metal hydroxide
AssigneeAllied Chemical Corporation
InventorsBruce E. Kurtz, Joel P. Guptill, Robert H. Fitch
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Abstract
In the process of making aqueous alkali metal hydroxide solution and diatomic halide gas by electrolysis of aqueous alkali metal halide solution in a bank of cationic permselective membrane cells, current efficiency is improved and/or concentration of the alkali metal hydroxide solution product is increased by feeding water to the cathode compartment of the first cell and then transferring the catholyte serially from cell to cell at incrementally increasing alkali metal hydroxide concentration, and withdrawing alkali metal hydroxide product solution from the last cell of the bank.
Claims15
In a bank of a plurality of cationic permselective membrane cells for electrolysis of aqueous alkali metal halide solution to form alkali metal hydroxide and diatomic halide gas, each cell comprising;
- a housing;
- an anode and a cathode located within the housing;
- a cationic permselective membrane separating the anode and the cathode and dividing the housing into an anode compartment and a cathode compartment;
- means for feeding enriched and for withdrawing partially depleted aqueous alkali metal halide solution to and from the anode compartment of each cell in the bank;
- means for feeding water or aqueous alkali metal hydroxide solution to the cathode compartment and for withdrawing aqueous alkali metal hydroxide solution from the cathode compartment of each cell in the bank;
- the improvement which comprises provision of:
- means for transferring catholyte serially from the cathode compartment of one or more preceding cells to the cathode compartment of one or more succeeding cells in the bank.
In the process of making aqueous alkali metal hydroxide solution and diatomic halide gas by electrolysis of aqueous alkali metal halide solution in a bank of a plurality of cationic permselective membrane cells, involving feeding enriched and withdrawing partially depleted aqueous alkali metal halide solution to and from the anode compartment of each cell, and feeding water or aqueous alkali metal hydroxide solution to and withdrawing catholyte comprising aqueous alkali metal hydroxide solution from the cathode compartment of each cell, the improvement which comprises transferring catholyte serially from the cathode compartment of one or more preceding cells to the cathode compartment of one or more succeeding cells in the bank.
Dependencies are inferred from the claim text.