Patent US3994830A successfully refreshed from Google Patents.
US3994830A
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US
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Process for the production of adsorbents of nitrohumic acid series with an improved alkali-resistance
Assignee: Hokutan Chemical Industry Co Ltd
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Filing: 1975-02-24
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Granted: 1976-11-30
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Expires: 1995-02-24
Abstract
Abstract An adsorbent of nitrohumic acid series with an improved alkali-resistance is prepared by insolubilizing calcium nitrohumate, kneading the insolubilized product with a water-soluble polyacrylamide in the presence of water, shaping the mixture into a desired form and then subjecting it to a heat treatment followed by an acid treatment. The adsorbent thus obtained can effectively be used for removing heavy metals from an alkaline effluent without causing any deterioration of adsorptive quality and coloration of the effluent.
Inventors
- 👤 Kazuki Terajima
- 👤 Shigeru Tomita
- 👤 Yoshindo Matsuda
- 👤 Keiji Abe
- 👤 Kozo Higuchi
- 👤 Keigo Iwashita
- 👤 Nobuyuki Nishiyama
- 👤 Yasuo Kato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:37
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/22; C; C02; C02F; C02F1/00; C02F1/28; C02F1/286
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
121 words
A process for the production of an adsorbent of nitrohumic acid series with an improved alkali-resistance, characterized by insolubilizing calcium nitrohumate by heating it at a temperature of 250°-300° C, adding a water-soluble polyacrylamide having a molecular weight of at least 5,000,000 to the resulting insoluble material, the amount of said polyacrylamide being from about 1-10 parts by weight per 100 parts by weight of calcium nitrohumate, kneading the mixture in the presence of water, shaping the kneaded mixture into a desired form and then subjecting the shaped article to a heat treatment at a temperature of about 120°-200° C, followed by an acid treatment wherein the acid used is selected from the class consisting of hydrohalic acid and sulfuric acid.
Claim 2
Dependent Claim
121 words
A process for the production of an adsorbent of nitrohumic acid series with an improved alkali-resistance, characterized by insolubilizing calcium nitrohumate by heating it at a temperature of 250°-300° C, adding a water-soluble polyacrylamide having a molecular weight of at least 5,000,000 to the resulting insoluble material, the amount of said polyacrylamide being from about 1-10 parts by weight per 100 parts by weight of calcium nitrohumate, kneading the mixture in the presence of water, shaping the kneaded mixture into a desired form and then subjecting the shaped article to a heat treatment at a temperature of about 120°-200° C, followed by an acid treatment wherein the acid used is selected from the class consisting of hydrohalic acid and sulfuric acid.
Claim 3
Dependent Claim
30 words
A process according to claim 1 wherein said water-soluble polyacrylamide is used in an amount of about 2-4 parts by weight per 100 parts by weight of said calcium nitrohumate.
Claim 4
Dependent Claim
22 words
A process according to claim 1 wherein the heat treatment of said shaped form is conducted for about 1 - 12 hours.
Claim 5
Dependent Claim
14 words
A process according to claim 1 wherein the knead mixture is shaped into granules.
Claim 6
Dependent Claim
13 words
A process according to claim 1 wherein said hydrohalic acid is hydrochloric acid.
Claim 7
Dependent Claim
17 words
A process according to claim 1 wherein the insolubilizing step is carried out for about 0.5-3 hours.
Claim 8
Dependent Claim
18 words
A process according to claim 1 wherein said water-soluble polyacrylamide has a molecular weight of at least 7,000,000.
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) | 1979-11-30 | 1980-05-31 | 1980-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-30 | 1984-05-31 | 1984-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-30 | 1988-05-31 | 1988-11-30 | $7700.00 | Window Closed / Lapsed |