Patent US4271671A successfully refreshed from Google Patents.
Patent US4187174A successfully refreshed from Google Patents.
US4187174A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diatomaceous earth filteraid and method for its manufacture
Assignee: Grefco Inc
•
Filing: 1978-12-27
•
Granted: 1980-02-05
•
Expires: 1998-12-27
Abstract
Abstract A method is provided for treating diatomaceous earth filteraids having a beer-soluble iron content of less than about 0.01% to further reduce the beer-soluble iron content by maintaining the filteraids in contact with a relatively small volume of an acid. In the filteraids so produced, the beer-soluble iron content can be reduced by as much as 70% to 100%. In making the filteraids of this invention, sulfuric acid in about 0.1 to about 3.0 normal solution can be used to treat the starting filteraids.
Inventors
- 👤 Richard B. Nielsen
- 👤 Charles J. Vogelsang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:16
CPC Classifications
C; C12; C12H; C12H1/00; C12H1/02; C12H1/04; C12H1/0408; B; B01; B01J; B01J20/00; B01J20/02; B01J20/10; B01J20/14
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
139 words
A process for producing diatomaceous earth filteraids of reduced beer-soluble iron content comprising the steps of mixing diatomaceous earth filteraids having a beer-soluble iron content of less than about 0.01% with an amount of aqueous acid solution less than about 15% by weight, based on the weight of the dry filteraids, and sufficient, but not in excess, to wet said diatomaceous earth filteraids uniformly, said acid being one which is capable of reducing said beer-soluble iron content within seven days when applied as a 3.0 normal aqueous solution to a diatomaceous earth filteraid in an amount of 15 % by weight based on the weight of the dry filteraid; and maintaining the acid solution in contact with the filteraids for a period of time sufficient to reduce the beer-soluble iron content of said filteraids by at least about 30%.
Claim 2
Dependent Claim
139 words
A process for producing diatomaceous earth filteraids of reduced beer-soluble iron content comprising the steps of mixing diatomaceous earth filteraids having a beer-soluble iron content of less than about 0.01% with an amount of aqueous acid solution less than about 15% by weight, based on the weight of the dry filteraids, and sufficient, but not in excess, to wet said diatomaceous earth filteraids uniformly, said acid being one which is capable of reducing said beer-soluble iron content within seven days when applied as a 3.0 normal aqueous solution to a diatomaceous earth filteraid in an amount of 15 % by weight based on the weight of the dry filteraid; and maintaining the acid solution in contact with the filteraids for a period of time sufficient to reduce the beer-soluble iron content of said filteraids by at least about 30%.
Claim 3
Dependent Claim
48 words
A process according to claim 1 wherein the amount of acid solution is from about 2% to 15% by weight based on the dry filteraid weight and the concentration of the acid solution is at least about 4 grams equivalents of acid per ton of diatomaceous earth filteraid.
Claim 4
Dependent Claim
40 words
A process according to claim 1 wherein the concentration of the acid solution is from about 4 gram equivalents of acid per ton of diatomaceous earth filteraid to about 400 gram equivalents of acid per ton of diatomaceous earth filteraid.
Claim 5
Dependent Claim
21 words
A process according to claim 1 wherein the acid is selected from the group consisting of acetic acid and oxalic acid.
Claim 6
Dependent Claim
13 words
A process according to claim 1 wherein the acid is an inorganic acid.
Claim 7
Dependent Claim
23 words
A process according to claim 5 wherein the acid is selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid.
Claim 8
Dependent Claim
12 words
A process according to claim 6 wherein the acid is sulfuric acid.
Claim 9
Dependent Claim
42 words
A process according to claim 7 wherein the concentration of the sulfuric acid solution is from about 0.1 normal to 3.0 normal and the amount of said acid solution is from 2% to 15% by weight based on the dry filteraid weight.
Claim 10
Dependent Claim
28 words
A process according to claim 1 wherein the acid solution is maintained in contact with the filteraids for a period of time between 0 and about 36 days.
Claim 11
Dependent Claim
20 words
A process according to claim 1 further including the step of drying the filteraid after contact with the acid solution.
Claim 12
Dependent Claim
27 words
A process according to claim 1 wherein the starting diatomaceous earth filteraids have a beer-soluble iron content of less than about 50 parts per million or 0.005%.
Claim 13
Dependent Claim
15 words
A process according to claim 1 wherein the starting diatomaceous earth filteraids are flux-calcined filteraids.
Claim 14
Dependent Claim
15 words
A process according to claim 1 wherein the starting diatomaceous earth filteraids are calcined filteraids.
Claim 15
Dependent Claim
25 words
A process according to claim 1 wherein the aqueous acid solution is mixed and maintained in contact with the diatomaceous earth filteraids at room temperature.
Claim 16
Dependent Claim
125 words
A process for producing diatomaceous earth filteraids of reduced beer-soluble iron content comprising the steps of mixing calcined diatomaceous earth filteraids having a beer-soluble iron content of less than about 0.01% with an aqueous acid solution of a strong or moderately strong inorganic acid of concentration of at least 4 gram equivalents of acid per ton of diatomaceous earth filteraid, said aqueous acid solution comprising less than about 15% by weight, based on the weight of the dry filteraids, and in an amount sufficient, but not in excess, to wet said diatomaceous earth filteraids uniformly; and maintaining the acid solution in contact with the filteraids for a period of time sufficient to reduce the beer-soluble iron content of said filteraids by at least about 30%.
Claim 17
Dependent Claim
125 words
A process for producing diatomaceous earth filteraids of reduced beer-soluble iron content comprising the steps of mixing calcined diatomaceous earth filteraids having a beer-soluble iron content of less than about 0.01% with an aqueous acid solution of a strong or moderately strong inorganic acid of concentration of at least 4 gram equivalents of acid per ton of diatomaceous earth filteraid, said aqueous acid solution comprising less than about 15% by weight, based on the weight of the dry filteraids, and in an amount sufficient, but not in excess, to wet said diatomaceous earth filteraids uniformly; and maintaining the acid solution in contact with the filteraids for a period of time sufficient to reduce the beer-soluble iron content of said filteraids by at least about 30%.
Claim 18
Dependent Claim
48 words
A process according to claim 15 wherein said inorganic acid is one which reduces beer-soluble iron content within seven days when applied as a 3.0 normal aqueous solution to a diatomaceous earth filteraid in an amount of 15% by weight based on the weight of the dry filteraid.
Claim 19
Dependent Claim
23 words
A process according to claim 16 wherein the acid is selected from the group consisting of sulfuric acid, nitric acid and hydrochloric acid.
Claim 20
Dependent Claim
12 words
A process according to claim 16 wherein the acid is sulfuric acid.
Claim 21
Dependent Claim
43 words
A process according to claim 18 wherein the concentration of the acid solution is from about 0.2 normal to about 3.0 normal and wherein the amount of acid solution is from about 2% to 15% by weight based on the dry filteraid weight.
Claim 22
Dependent Claim
20 words
A process according to claim 16 further including the step of drying the filteraids after contact with the acid solution.
Claim 23
Dependent Claim
27 words
A process according to claim 16 wherein the starting diatomaceous earth filteraids have a beer-soluble iron content of less than about 50 parts per million or 0.005%.
Claim 24
Dependent Claim
25 words
A process according to claim 15 wherein the aqueous acid solution is mixed and maintained in contact with the diatomaceous earth filteraids at room temperature.
References Cited (Backward Citations)
USRE20844E
Cited
US665652A
Cited
US1992547A
Cited
US2322674A
Cited
US2701240A
Cited
US3013981A
Cited
US3940498A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-02-04 | 1983-08-06 | 1984-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-04 | 1987-08-06 | 1988-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-04 | 1991-08-06 | 1992-02-05 | $7700.00 | Window Closed / Lapsed |