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US3870060A
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Method of removing monovalent inorganic acids from an aqueous solution containing metal salts of the acids
Assignee: Stora Enso Oyj
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Filing: 1974-02-26
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Granted: 1975-03-11
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Expires: 1994-02-26
Abstract
Abstract Monovalent inorganic acids such as hydrofluoric acid can be removed from spent pickling baths by bringing the bath, which shall have a content of sulphuric acid at least equivalent to the metal ion content of the bath, into contact with an organic liquid which contains a compound which forms an adduct with the monovalent inorganic acids. The organic phase extracts the monovalent inorganic acids from the aqueous phase. Metals can then be recovered from the aqueous phase, if desired. The organic phase may then be washed with water, resulting in the monovalent inorganic acids being transferred from the organic phase into the water. The acid aqueous solution thus produced may be used for preparing a fresh pickling bath.
Inventors
- 👤 Jan-Olov Liljenzin
- 👤 Hans Reinhardt
- 👤 Helge Jan Arnold Rydberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:26
CPC Classifications
B; B01; B01D; B01D11/00; B01D11/04; B01D11/0488; C; C23; C23G; C23G1/00; C23G1/36; Y; Y10; Y10S; Y10S423/00; Y10S423/01; Y10S423/02
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
90 words
A METHOD OF REMOVING MONOVALENT INORGANIC ACIDS FROM AN AQUEOUS SOLUTION CONTAINING METAL SALTS OF SAID MONOVALENT INORGANIC ACIDS SAID MONOVALENT ACIDS BEING NITRIC, HYDROCHLORIC, OR HYDROFLUORIC ACID, SAID METHOD COMPRISING OF ADDING TO SAID AQUEOUS SOLUTION SULPHURIC ACID AT LEAST EQUIVALENT IN AMOUNT TO THE METAL ION CONTENT OF THE SOLUTION, EXTRACTING SAID MONOVALENT INORGANIC ACIDS BY BRINGING THE SOLUTION INTO CONTACT WITH AN ORGANIC LIQUID PHASE, SAID ORGANIC LIQUID PHASE INCLUDING COMPOUNDS FORMING ADDUCTS WITH SAID MONOVALENT ACIDS, AND SEPARATING SAID ORGANIC LIQUID PHASE FROM SAID AQUEOUS SOLUTION.
Claim 2
Independent Claim
90 words
A METHOD OF REMOVING MONOVALENT INORGANIC ACIDS FROM AN AQUEOUS SOLUTION CONTAINING METAL SALTS OF SAID MONOVALENT INORGANIC ACIDS SAID MONOVALENT ACIDS BEING NITRIC, HYDROCHLORIC, OR HYDROFLUORIC ACID, SAID METHOD COMPRISING OF ADDING TO SAID AQUEOUS SOLUTION SULPHURIC ACID AT LEAST EQUIVALENT IN AMOUNT TO THE METAL ION CONTENT OF THE SOLUTION, EXTRACTING SAID MONOVALENT INORGANIC ACIDS BY BRINGING THE SOLUTION INTO CONTACT WITH AN ORGANIC LIQUID PHASE, SAID ORGANIC LIQUID PHASE INCLUDING COMPOUNDS FORMING ADDUCTS WITH SAID MONOVALENT ACIDS, AND SEPARATING SAID ORGANIC LIQUID PHASE FROM SAID AQUEOUS SOLUTION.
Claim 3
Independent Claim
90 words
A method of removing monovalent inorganic acids from an aqueous solution containing metal salts of said monovalent inorganic acids said monovalent acids being nitric, hydrochloric, or hydrofluoric acid, said method comprising of adding to said aqueous solution sulphuric acid at least equivalent in amount to the metal ion content of the solution, extracting said monovalent inorganic acids by bringing the solution into contact with an organic liquid phase, said organic liquid phase including compounds forming adducts with said monovalent acids, and separating said organic liquid phase from said aqueous solution.
Claim 4
Independent Claim
90 words
A method of removing monovalent inorganic acids from an aqueous solution containing metal salts of said monovalent inorganic acids said monovalent acids being nitric, hydrochloric, or hydrofluoric acid, said method comprising of adding to said aqueous solution sulphuric acid at least equivalent in amount to the metal ion content of the solution, extracting said monovalent inorganic acids by bringing the solution into contact with an organic liquid phase, said organic liquid phase including compounds forming adducts with said monovalent acids, and separating said organic liquid phase from said aqueous solution.
Claim 5
Dependent Claim
25 words
A method as claimed in claim 1, comprising decomposing said adducts to release said inorganic acids, and removing said inorganic acids from the organic phase.
Claim 6
Dependent Claim
24 words
A method as claimed in claim 2, comprising recovering the acids from the organic phase by contacting the organic phase with an aqueous solution.
Claim 7
Dependent Claim
22 words
A method as claimed in claim 2, comprising removing metal ions from the organic phase prior to the decomposition of the adduct.
Claim 8
Dependent Claim
22 words
A method as claimed in claim 2, comprising removing metal ions from the organic phase after the removal of monovalent inorganic acids.
Claim 9
Dependent Claim
23 words
A method as claimed in claim 1, comprising recovering metal ions from the aqueous solution after the extraction of the monovalent inorganic acids.
Claim 10
Dependent Claim
16 words
A method as claimed in claim 6, comprising precipitating metal ions in the form of hydroxides.
Claim 11
Dependent Claim
21 words
A method as claimed in claim 6, comprising extracting metal ions from the aqueous solution by means of an organic phase.
Claim 12
Dependent Claim
116 words
A method as claimed in claim 1, wherein the aqueous solution consists of a pickling bath for pickling metals, the bath containing nitric acid and hydrofluoric acid and, after having had sulphuric acid added in a quantity at least equivalent to the metal ion content, being brought into contact with an organic liquid phase containing compounds which form adducts with hydrofluoric acid and nitric acid, whereafter the organic liquid phase is washed with water to remove the acids from the organic phase, and the resultant aqueous solution of hydrofluoric acid and nitric acid is then recycled to the pickling bath for reuse, and the metal ions are precipitated by adding alkali to the extracted acid solution.
Claim 13
Dependent Claim
88 words
A method as claimed in claim 1, wherein the aqueous solution consists of solutions originating from the leaching of sulphidic ores with mixtures of sulphuric acid and nitric acid, the developed nitrous gases being recovered by oxidation to form nitric acid, the leaching solution being brought into contact with an organic liquid phase containing a compound which forms adducts with nitric acid, thereafter the nitric acid being removed from the organic phase bY leaching it with water, and the nitric acid being recycled to the main leaching process.
Claim 14
Dependent Claim
17 words
A method as claimed in claim 1 wherein the organic liquid phase is substantially immiscible with water.
Claim 15
Dependent Claim
158 words
In a method of pickling metal articles and a recovery of a pickling solution the improvement comprising pickling the articles with an aqueous solution containing a monovalent inorganic acid, adding sulphuric acid to the spent pickling solution in a quantity to make the sulphuric acid content of the solution at least equivalent to the metal ion content of the solution, bringing the spent pickling solution into contact with an organic liquid containing a compound which forms an adduct with the monovalent inorganic acid, so as to extract said monovalent inorganic acid from the spent pickling solution into the organic liquid, bringing the organic liquid into contact with water so as to decompose the adduct and to extract the monovalent inorganic acid, thus released, from the organic liquid into the water, returning the aqueous acid solution from the second extraction process to the pickling process, and precipitating the metal content of the aqueous solution from the first extraction process.
Claim 16
Dependent Claim
158 words
In a method of pickling metal articles and a recovery of a pickling solution the improvement comprising pickling the articles with an aqueous solution containing a monovalent inorganic acid, adding sulphuric acid to the spent pickling solution in a quantity to make the sulphuric acid content of the solution at least equivalent to the metal ion content of the solution, bringing the spent pickling solution into contact with an organic liquid containing a compound which forms an adduct with the monovalent inorganic acid, so as to extract said monovalent inorganic acid from the spent pickling solution into the organic liquid, bringing the organic liquid into contact with water so as to decompose the adduct and to extract the monovalent inorganic acid, thus released, from the organic liquid into the water, returning the aqueous acid solution from the second extraction process to the pickling process, and precipitating the metal content of the aqueous solution from the first extraction process.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |