US4309206A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of odorless prilled urea-dicyandiamide fertilizers
Assignee: Evonik Operations GmbH
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Filing: 1980-09-26
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Granted: 1982-01-05
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Expires: 2000-09-26
Abstract
Abstract Odorless prilled urea-dicyandiamide fertilizers are produced by melting a mixture of urea and dicyandiamide containing 5% to 35% by weight of dicyandiamide nitrogen, based on the total nitrogen of the mixture, at a temperature below 135° C. and then prilling the molten material to form a free-flowing globular product.
Inventors
- 👤 Horst Michaud
- 👤 Heinrich Rock
- 👤 Josef Seeholzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:59
CPC Classifications
C; C05; C05C; C05C7/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
65 words
A method for producing an odorless solid urea-dicyandiamide fertilizer which comprises heating a mixture of urea and dicyandiamide which mixture contains 5-30% by weight of dicyandiamide nitrogen, based on the total weight of nitrogen in the mixture, to form a molten mixture and then prilling the molten mixture, said heating being so carried out that the temperature of said mixture does not exceed 125° C.
Claim 2
Independent Claim
65 words
A method for producing an odorless solid urea-dicyandiamide fertilizer which comprises heating a mixture of urea and dicyandiamide which mixture contains 5-30% by weight of dicyandiamide nitrogen, based on the total weight of nitrogen in the mixture, to form a molten mixture and then prilling the molten mixture, said heating being so carried out that the temperature of said mixture does not exceed 125° C.
Claim 3
Independent Claim
69 words
A method for producing an odorless solid urea-dicyandiamide fertilizer which comprises preparing a mixture of urea and dicyandiamide in such proportions that it contains from 5% to 30% by weight of dicyandiamide nitrogen, based on the total weight of nitrogen in the mixture, heating the mixture under conditions such that its temperature does not exceed 125° C. to convert it to molten form and then prilling the molten mixture.
Claim 4
Independent Claim
69 words
A method for producing an odorless solid urea-dicyandiamide fertilizer which comprises preparing a mixture of urea and dicyandiamide in such proportions that it contains from 5% to 30% by weight of dicyandiamide nitrogen, based on the total weight of nitrogen in the mixture, heating the mixture under conditions such that its temperature does not exceed 125° C. to convert it to molten form and then prilling the molten mixture.
Claim 5
Dependent Claim
20 words
The method defined in claim 1 wherein the temperature of the molten mixture is maintained between 110° and 125° C.
Claim 6
Dependent Claim
35 words
The method defined in claim 1 wherein a medium-strong to weak acid is added to the molten mixture in an amount of 0.1 to 2.5% by weight, based on the weight of the fertilizer mixture.
Claim 7
Dependent Claim
33 words
The method defined in claim 4 wherein the medium-strong to weak acid is heated together with urea and dicyandiamide or is subsequently added to the molten mixture which contains the urea and dicyandiamide.
Claim 8
Dependent Claim
19 words
The method defined in claim 4 wherein the added acid is an inorganic acid or an acid-reacting salt thereof.
Claim 9
Dependent Claim
16 words
The method defined in claim 4 wherein the added acid is formic acid or acetic acid.
Claim 10
Dependent Claim
17 words
The method defined in claim 4 wherein the added acid is glycolic acid, lactic or citric acid.
Claim 11
Dependent Claim
14 words
The method defined in claim 4 wherein the added acid is an amino acid.
Claim 12
Dependent Claim
19 words
The method defined in claim 1 wherein the temperature of the molten mixture is between 120° and 125° C.
References Cited (Backward Citations)
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Cited
US3802903A
Cited
JPS4733905U
Cited
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Cited
US4073633A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-04 | 1985-07-06 | 1986-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-04 | 1989-07-06 | 1990-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-04 | 1993-07-06 | 1994-01-05 | $7700.00 | Window Closed / Lapsed |