초록 ▼

Bipolar membrane electrodialysis methods for salt splitting polyvalent metal salts, where the metal cation can form substantially insoluble precipitates in the presence of hydroxyl ions can now be used in recovering acid and base values from a salt streams without precipitates fouling cell operation

Bipolar membrane electrodialysis methods for salt splitting polyvalent metal salts, where the metal cation can form substantially insoluble precipitates in the presence of hydroxyl ions can now be used in recovering acid and base values from a salt streams without precipitates fouling cell operation and causing shutdown. The introduction of an acid to the chamber where metal hydroxides would form inhibits their development or neutralizes formed solids, allowing salt splitting to continue. Salt splitting methods of the invention performed with a three compartment bipolar electrodialysis cell are useful in producing concentrated and purified acid forms, such as 2-keto-L-gluconic acid, H(KLG), a key intermediate in the production of ascorbic acid.

대표청구항 ▼

1. A method for splitting salts, which comprises the steps of:(i) providing an aqueous solution of a salt, said solution comprising cations and anions; (ii) separating the cations from said aqueous solution by transporting across a cation exchange membrane; (iii) converting the separated cations int

1. A method for splitting salts, which comprises the steps of:(i) providing an aqueous solution of a salt, said solution comprising cations and anions; (ii) separating the cations from said aqueous solution by transporting across a cation exchange membrane; (iii) converting the separated cations into the corresponding hydroxide by the introduction of hydroxyl groups supplied across a bipolar membrane; (iv) forming a first useful product by acidifying the hydroxide; (v) forming a second useful product either by: (a) acidifying the anions remaining in said aqueous solution after separating the cations therefrom (step ii) by the addition of protons supplied across a bipolar membrane to form the corresponding free acid of said anion, or (b) by separating the anions from said aqueous solution by transporting through an anion exchange membrane, and converting the separated anions to the corresponding free acid by the addition of protons supplied across a bipolar membrane.