US3867516A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing a pigment on an iron oxide base
Assignee: Societe des Mines et Fonderies de Zinc de la Vieille Montagne SA
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Filing: 1972-04-10
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Granted: 1975-02-18
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Expires: 1992-04-10
Abstract
Abstract In a method of preparing a pigment on an iron-oxide base from a sulphate solution containing in particular ferrous sulphate and derived from the leaching of zinc residues, said solution is neutralized and oxidized to simultaneously precipitate the hydrolyzable impurities together with a small quantity of iron, then the supernatant remaining liquid is separated from the precipitate and is neutralized and oxidized to precipitate most of the iron as an oxide, and the latter precipitate is treated in a basic medium to remove the small amount of sulphate ion present therein.
Inventors
- 👤 Fernand Jacques Joseph Bodson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:00
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/22; C09C1/24; C01; C01G; C01G49/00; C01G49/02; C01G49/06; C01G49/08; C01P; C01P2006/00; C01P2006/60; C01P2006/80
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
133 words
A METHOD OF PREPARING AN IRON OXIDE PIGMENT BASE FROM A SULFATE SOLUTION DERIVED FROM THE LEACHING OF ZINC RESIDUES AND CONTAINING, IN PARTICULAR, FERROUS SULFATE COMPRISING: HEATING SAID SULFATE SOLUTION TO A TEMPERATURE OF ABOUT 90*C., ADDING TO SAID SOLUTION A ZINC OXIDE-CONTAINING MATERIAL TO RAISE THE PH TO A VALUE ABOVE 2, BLOWING AIR INTO SAID SOLUTION TO PRECIPITATE THE HYDROLYZABLE IMPURITIES TOGETHER WITH ABOUT 10% OF THE IRON, SEPARATING THE FILTRATE, MAINTAINING SAID FILTRATE AT A TEMPERATURE OF ABOUT 90*C. AND ADDING SUFFICIENT ZINC OXIDE-CONTAINING MATERIAL TO OBTAIN A PH VALUE BETWEEN 1.7 AND 2.5, BLOWING DISPERSED AIR INTO SAID FILTRATE TO PRECIPITATE IRON IN THE FORM OF GOETHITE AND TREATING SAID FILTRATE TO P RECIP ITATE WITH A BASIC LIQUID MEDIUM TO REMOVE SULFATE IRONS PRESENT IN SAID PRECIPITATE.
Claim 2
Independent Claim
133 words
A METHOD OF PREPARING AN IRON OXIDE PIGMENT BASE FROM A SULFATE SOLUTION DERIVED FROM THE LEACHING OF ZINC RESIDUES AND CONTAINING, IN PARTICULAR, FERROUS SULFATE COMPRISING: HEATING SAID SULFATE SOLUTION TO A TEMPERATURE OF ABOUT 90*C., ADDING TO SAID SOLUTION A ZINC OXIDE-CONTAINING MATERIAL TO RAISE THE PH TO A VALUE ABOVE 2, BLOWING AIR INTO SAID SOLUTION TO PRECIPITATE THE HYDROLYZABLE IMPURITIES TOGETHER WITH ABOUT 10% OF THE IRON, SEPARATING THE FILTRATE, MAINTAINING SAID FILTRATE AT A TEMPERATURE OF ABOUT 90*C. AND ADDING SUFFICIENT ZINC OXIDE-CONTAINING MATERIAL TO OBTAIN A PH VALUE BETWEEN 1.7 AND 2.5, BLOWING DISPERSED AIR INTO SAID FILTRATE TO PRECIPITATE IRON IN THE FORM OF GOETHITE AND TREATING SAID FILTRATE TO P RECIP ITATE WITH A BASIC LIQUID MEDIUM TO REMOVE SULFATE IRONS PRESENT IN SAID PRECIPITATE.
Claim 3
Dependent Claim
15 words
A method as claImed in claim 1 wherein said zinc oxide-containing material is calcined blende.
Claim 4
Independent Claim
20 words
A method as claimed in claiam 1 wherein the ferrous sulfate solution is maintained at a pH value of 4.
Claim 5
Dependent Claim
18 words
A method as claimed in claim 1 wherein the filtrate is maintained at a pH value of 2.
Claim 6
Dependent Claim
28 words
A method as claimed in claim 1 wherein finely dispersed air is blown into said filtrate at the rate of 10NM3 per hour and per M3 of solution.
Claim 7
Dependent Claim
27 words
A method as claimed in claim 1 wherein said geothite precipitate is washed at 90*C. in water having a basic pH value to remove said sulfate ions.
Claim 8
Dependent Claim
21 words
A method as claimed in claim 6 wherein bicarbonate of soda is added to the water to make the latter basic.
Claim 9
Dependent Claim
36 words
A method as claimed in claim 1 wherein after removal of the sulfate ions, the goethite precipitate is washed in water and dried at a temperature not greater than 150*C. to give a yellow iron pigment.
Claim 10
Dependent Claim
37 words
A method as claimed in claim 1 wherein after removal of the sulfate ions, said goethite precipitate is washed in water and then calcined at a temperature between 700* and 750*C. to give a red iron pigment.
Claim 11
Dependent Claim
19 words
A method as claimed in claim 9 wherein said washed goethite precipitate is calcined for at least 4 hours.
Claim 12
Dependent Claim
50 words
A method as claimed in claim 1 wherein said goethite precipitate is reduced by hydrogen under pressure in a 5 N sodium solution at a temperature between 175* and 250*C. and then washed in water and dried at a temperature not greater than 150*C. to give a black iron pigment.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |