Patent EP0594004A1 successfully refreshed from Google Patents.
US7175819B2
Expired / Lapsed
US
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Regeneration of cupric etchants and recovery of copper sulfate
Assignee: Phibro Tech Inc
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Filing: 2005-03-04
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Granted: 2007-02-13
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Expires: 2025-03-04
Abstract
Abstract Spent, acidic solutions comprising cupric chloride and hyrdrochloric acid from the copper etching process are regenerated by a process in which the acid is subjected to distillation with sulfuric acid. In one embodiment, the process comprises (a) providing a spent etchant comprising at least about 10% by weight chloride and at least about 5% dissolved copper; (b) adding at least about 2 moles of sulfuric acid per mole of dissolved copper to the spent etching solution, thereby converting copper chloride into hydrochloric acid and precipitated copper sulfate; (c) distilling the mixture from step (b) to vaporize at least a portion of the hydrochloric acid; (d) condensing at least a portion of the vaporized hydrochloric acid; (e) separating at least a portion of the precipitated copper sulfate from the residual liquid, wherein said residual liquid comprises sulfuric acid; and (f) reusing at least a portion of the residual liquid as a sulfuric acid source in step (b).
Inventors
- 👤 Gang Zhao
- 👤 H. Wayne Richardson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:53
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/46; C01; C01G; C01G3/00; C01G3/10; B; B01; B01D; B01D3/00; B01D3/34; C01B; C01B17/00; C01B17/69; C01B17/90; C01B17/901; C01B7/00; C01B7/01; C01B7/07; C01B7/0706; C01B7/0712
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
140 words
A process for the regeneration of a spent etching solution comprising dissolved copper chloride, the process comprising the steps of: (a) providing a spent etchant comprising at least about 10% by weight chloride and at least about 5% dissolved copper; (b) adding at least about 2 moles of sulfuric acid per mole of dissolved copper to the spent etching solution, thereby converting copper chloride into hydrochloric acid and precipitated copper sulfate; (c) distilling the mixture from step (b) to vaporize at least a portion of the hydrochloric acid; (d) condensing at least a portion of the vaporized hydrochloric acid; (e) separating at least a portion of the precipitated copper sulfate from the residual liquid, wherein said residual liquid comprises sulfuric acid; and (f) reusing at least a portion of the residual liquid as a sulfuric acid source in step (b).
Claim 2
Dependent Claim
140 words
A process for the regeneration of a spent etching solution comprising dissolved copper chloride, the process comprising the steps of: (a) providing a spent etchant comprising at least about 10% by weight chloride and at least about 5% dissolved copper; (b) adding at least about 2 moles of sulfuric acid per mole of dissolved copper to the spent etching solution, thereby converting copper chloride into hydrochloric acid and precipitated copper sulfate; (c) distilling the mixture from step (b) to vaporize at least a portion of the hydrochloric acid; (d) condensing at least a portion of the vaporized hydrochloric acid; (e) separating at least a portion of the precipitated copper sulfate from the residual liquid, wherein said residual liquid comprises sulfuric acid; and (f) reusing at least a portion of the residual liquid as a sulfuric acid source in step (b).
Claim 3
Dependent Claim
41 words
The process of claim 1 , wherein the process operates on a continuous basis, and wherein the spent etchant, the sulfuric acid, or both further comprise at least one mole of water per mole of dissolved copper in the spent etchant.
Claim 4
Dependent Claim
41 words
The process of claim 1 , wherein the process operates on a batch basis, and wherein the spent etchant, the sulfuric acid, or both further comprise at least one mole of water per mole of dissolved copper in the spent etchant.
Claim 5
Dependent Claim
31 words
The process of claim 1 , wherein the quantity of sulfuric acid added is at least about 3 moles of sulfuric acid per mole of dissolved copper in the spent etchant.
Claim 6
Dependent Claim
31 words
The process of claim 1 , wherein the quantity of sulfuric acid added is at least about 3.5 moles of sulfuric acid per mole of dissolved copper in the spent etchant.
Claim 7
Dependent Claim
32 words
The process of claim 1 , wherein the quantity of sulfuric acid added is between about 4 moles and about 6 moles sulfuric acid per mole dissolved copper in the spent etchant.
Claim 8
Dependent Claim
32 words
The process of claim 1 , wherein the quantity of sulfuric acid added is between about 3.5 moles and about 5 moles sulfuric acid per mole dissolved copper in the spent etchant.
Claim 9
Dependent Claim
25 words
The process of claim 1 , wherein at least 4 parts by weight of sulfuric acid added per 6 parts by weight of spent etchant.
Claim 10
Dependent Claim
25 words
The process of claim 1 , wherein at least 5 parts by weight of sulfuric acid added per 5 parts by weight of spent etchant.
Claim 11
Dependent Claim
25 words
The process of claim 1 , wherein at least 6 parts by weight of sulfuric acid added per 4 parts by weight of spent etchant.
Claim 12
Dependent Claim
25 words
The process of claim 1 , wherein the distillation in step (c) occurs at a temperature of from about 95° C. to about 135° C.
Claim 13
Dependent Claim
25 words
The process of claim 1 , wherein the distillation in step (c) occurs at a temperature of from about 120° C. to about 135° C.
Claim 14
Dependent Claim
22 words
The process of claim 1 , wherein the distillation in step (c) occurs at a pressure of less than about 1 atm.
Claim 15
Dependent Claim
24 words
The process of claim 13 , wherein the distillation in step (c) occurs at a pressure of from about 0.7 to about 0.99 atm.
Claim 16
Dependent Claim
45 words
The process of claim 1 , wherein the separated copper sulfate comprises residual liquid, the process further comprising contacting the separated copper sulfate with a base to neutralize at least a portion of the sulfuric acid in the residual liquid contacting the separated copper sulfate.
Claim 17
Dependent Claim
22 words
The process of claim 1 , wherein the precipitated copper sulfate is separated from the residual liquid comprising sulfuric acid by centrifugation.
Claim 18
Dependent Claim
40 words
The process of claim 1 , wherein the recovered hydrochloric acid comprises at least about 8 moles hydrochloric acid per liter, further comprising the step of formulating at least a portion of the condensed hydrochloric acid into a copper etchant.
Claim 19
Dependent Claim
26 words
The process of claim 1 , wherein the spent etching solution in step (a) comprises from about 4 to about 8 moles per liter total chloride.
Claim 20
Dependent Claim
23 words
The process of claim 1 , wherein step (a) further comprises concentrating the spent etchant to at least about 20 weight % chloride.
Claim 21
Dependent Claim
29 words
The process of claim 1 , wherein step (a) further comprises concentrating a spent etching solution to provide a spent etchant comprising at least about 30 weight % chloride.
Claim 22
Dependent Claim
26 words
The process of claim 1 , wherein the separated copper sulfate comprises at least about 90% by weight of copper sulfate pentahydrate and/or copper sulfate monohydrate.
Claim 23
Dependent Claim
21 words
The process of claim 21 , wherein more than 60 mole percent of the separated copper sulfate comprises copper sulfate pentahydrate.
Claim 24
Dependent Claim
21 words
The process of claim 21 , wherein more than 60 mole percent of the separated copper sulfate comprises copper sulfate monohydrate.
Claim 25
Dependent Claim
21 words
The process of claim 21 , wherein more than 80 mole percent of the separated copper sulfate comprises copper sulfate monohydrate.
Claim 26
Dependent Claim
43 words
The process of claim 1 , further comprising the step of converting at least a portion of the separated copper sulfate into a form where wherein the copper can be injected into wood, and injecting the copper into wood as a wood preservative.
Claim 27
Dependent Claim
25 words
The process of claim 1 , further comprising the step of converting at least a portion of the separated copper sulfate into a fungicidal composition.
Claim 28
Dependent Claim
21 words
The process of claim 1 , further comprising the step of washing the separated copper sulfate to further remove residual liquid.
Claim 29
Dependent Claim
36 words
The process of claim 1 , wherein the composition comprising reaction products of the spent etchant and sulfuric acid is steam distilled to vaporize more than 98% of the chloride in the composition as hydrochloric acid.
Claim 30
Dependent Claim
26 words
The process of claim 1 , wherein at least about 90 weight % of the Cu in the spent etchant is recovered as separated copper sulfate.
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