Patent US3634032A successfully refreshed from Google Patents.
US3634032A
Expired / Lapsed
US
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Purification of sand
Assignee: British Industrial Sand Ltd
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Filing: 1969-09-09
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Granted: 1972-01-11
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Expires: 1989-09-09
Abstract
Abstract This invention relates to the purification of sand containing iron or iron compound impurities. The sand to be purified is contacted with concentrated hydrochloric acid which dissolves the impurities and the purified sand is freed from the unreacted acid and reaction products. This unreacted acid and the reaction products are then heated, giving hydrogen chloride gas and a decomposition product which is sent to waste. The hydrogen chloride gas is converted to concentrated hydrochloric acid which is then used to purify fresh sand.
Inventors
- 👤 Herbert Daymond Segrove
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:36
CPC Classifications
C; C07; C07D; C07D233/00; C07D233/54; C07D233/66; C07D233/72; C07D233/80; C07D233/82; B; B22; B22C; B22C5/00; B22C5/18; B22C5/185; C03; C03C; C03C1/00; C03C1/02; C03C1/022
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
19 words
The process of claim 1 in which said sand is heated to a temperature of at least 90* C.
Claim 2
Dependent Claim
22 words
The process of claim 1 in which said sand is contacted with said concentrated hydrochloric acid for from 30 to 90 minutes.
Claim 3
Dependent Claim
20 words
The process of claim 3 in which said sand is contacted with said concentrated hydrochloric acid for about 60 minutes.
Claim 4
Dependent Claim
26 words
The process of claim 1 in which said sand to be purified is contacted with an amount of said concentrated hydrochloric acid of about 5 percent.
Claim 5
Dependent Claim
25 words
The process of claim 1 in which said so treated sand is freed from said unreacted acid and impurity reaction products by washing with water.
Claim 6
Dependent Claim
17 words
The process of claim 6 in which said washing is effected by alternate filtration and washing steps.
Claim 7
Dependent Claim
29 words
The process of claim 1 in which said unreacted acid and impurity reaction product are sprayed through hot combustion gases to give said hydrogen chloride gas and decomposition product.
Claim 8
Dependent Claim
31 words
The process of claim 1 in which said unreacted acid and impurity reaction products are sprayed into a heated rotating refractory hearth to give saId hydrogen chloride gas and decomposition product.
Claim 9
Dependent Claim
28 words
The process of claim 1 in which said hydrogen chloride gas is absorbed in water to convert it to concentrated hydrochloric acid of the desired strength for recycling.
References Cited (Backward Citations)
US2031969A
Cited
US2155119A
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US2592580A
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US2752223A
Cited
US2952516A
Cited
US3236596A
Cited
US3399964A
Cited
US3442608A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |