US4820325A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of toxicant-impregnated filter cake
Assignee: Innophos Inc
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Filing: 1987-10-22
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Granted: 1989-04-11
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Expires: 2007-10-22
Abstract
Abstract A filter cake formed of a glass precursor material and impregnated with a normally leachable toxicant can be heated, preferably with at least one other glass precursor material, at a sufficiently high temperature to form a molten composition which solidifies, upon cooling, to form a glass. The normally leachable toxicant becomes fixed within the glass rendering it substantially more non-leachable allowing for a more environmentally sound means for disposal, e.g., by landfill techniques. The process can be used to treat the arsenic sulfide-impregnated filter cake derived from the manufacture of food grade phosphoric acid.
Inventors
- 👤 Donald R. Wheeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:53
CPC Classifications
B; B09; B09B; B09B3/00; B09B3/20; B09B3/25; B09B3/29; C; C03; C03C; C03C1/00; C03C1/002; Y; Y10; Y10S; Y10S422/00; Y10S422/90
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
71 words
A process for the fixation of a normally leachable toxicant within a filter cake formed of a glass precursor material, thereby rendering the toxicant substantially more non-leachable therefrom, which comprises forming a filter cake of siliceous glass precursor material having toxicant material entrapped therein, heating the filter cake containing the toxicant to fusion temperature to form a molten composition, and cooling said molten composition to form a glass containing the toxicant.
Claim 2
Dependent Claim
71 words
A process for the fixation of a normally leachable toxicant within a filter cake formed of a glass precursor material, thereby rendering the toxicant substantially more non-leachable therefrom, which comprises forming a filter cake of siliceous glass precursor material having toxicant material entrapped therein, heating the filter cake containing the toxicant to fusion temperature to form a molten composition, and cooling said molten composition to form a glass containing the toxicant.
Claim 3
Dependent Claim
18 words
A process as claimed in claim 1 wherein the siliceous material forming the filter cake is diatomaceous earth.
Claim 4
Dependent Claim
14 words
A process as claimed in claim 1 wherein the toxicant is an arsenic sulfide.
Claim 5
Dependent Claim
18 words
A process as claimed in claim 3 wherein the siliceous material forming the filter cake is diatomaceous earth.
Claim 6
Dependent Claim
25 words
A process as claimed in claim 3 wherein the filter cake and toxicant are derived from the filtration of phosphoric acid containing said arsenic sulfide.
Claim 7
Dependent Claim
24 words
A process as claimed in claim 1 wherein the filter cake is mixed with at least one other glass precursor material prior to heating.
Claim 8
Dependent Claim
24 words
A process as claimed in claim 5 wherein the filter cake is mixed with at least one other glass precursor material prior to heating.
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) | 1992-04-10 | 1992-10-10 | 1993-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-10 | 1996-10-10 | 1997-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-10 | 2000-10-10 | 2001-04-11 | $7700.00 | Window Closed / Lapsed |