US 2019/0292680 A1 · ELECTRO-CERAMIC COATING BATH CLEANUP BY A HYBRID ION EXCHANGE PRECIPITATION PROCESS

Abstract

A process and a system for cleaning excess aluminum from coating baths, e.g. anodization bath solutions, so that they can be reused in an effective manner is provided. The process comprises first passing a portion of the anodization bath solution having excess aluminum through a strong acid cation exchange column in a Na+ form, allowing the effluent to age thereby precipitating cryolite from the effluent; removing the precipitated cryolite from the effluent and then passing the effluent through a strong acid cation exchange column in the NH4+ form, in a preferred embodiment back through the first column, to restore NH4+ to the anodization bath solution and then adding the effluent back in to the anodization bath solution.

Claims27

Dependent claims

A method for removing aluminum from an anodization bath solution comprising the steps of:

a) providing an aqueous acidic anodization solution containing NH4+ and aluminum and fluoride;
b) passing the anodization solution through a strong acid cation exchange column in the Na+ form and exchanging Na+ for NH4+ in the anodization solution and collecting the effluent;
c) removing formed insoluble cryolite, Na3AlF6, from the effluent of step b);
and
d) taking the effluent from step c), after removing the cryolite, and passing it through a strong acid cation exchange column in the NH4+ form and exchanging NH4+ for Na+ in the effluent and collecting the resulting effluent.

2 more elements

A system for removing aluminum from coating bath solutions comprising:

a) a resin bed or IEX column hydraulically connected to a coating tank for coating bath solutions comprising dissolved aluminum, the resin bed or IEX column containing a strong acid cation exchange resin having Na+ present as the exchange ion for removing NH4+ from the coating bath solution and adding Na+ to form a first effluent;
b) a precipitation tank, hydraulically connected to the resin bed or IEX column, for receiving a first effluent from the resin bed or IEX column and precipitating insoluble aluminum species;
c) a solids separation device, hydraulically connected to the precipitation tank and capable of removing insoluble precipitates from the first effluent, optionally by filtration and/or centrifugation to thereby form a supernatant liquid;
d) a strong acid cation exchange resin having NH4+ as the exchange ion, hydraulically connected to the solids separation device, for removing Na+ and adding NH4+ to the supernatant liquid, to thereby form a second effluent, comprising less dissolved aluminum than the coating bath solution, and optionally hydraulically connected to the coating tank for return of the second effluent thereto.

1 more element

Dependencies are inferred from the claim text.

Electro-ceramic coating bath cleanup by a hybrid ion exchange precipitation process

Life of this patent

Electro-ceramic coating bath cleanup by a hybrid ion exchange precipitation process

Life of this patent

Abstract

Claims27