US3933459A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-magnesium ammonium polyphosphate solutions
Assignee: FERTILIZER INDUSTRIES Inc
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Filing: 1974-10-11
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Granted: 1976-01-20
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Expires: 1994-10-11
Abstract
Abstract A stable ammonium polyphosphate fertilizer solution having a relatively high amount of magnesium is prepared by mixing aqueous ammonia with wet-process superphosphoric acid in a reaction zone to give a P 2 O 5 /N weight ratio within the range 3.6-4.0. The temperature of the reaction mixture is preferably maintained at about 50°-70°C. but the product solution should be cooled to about 25°-35°C. prior to storage. The product solution shows relatively low corrosion toward carbon steel storage tanks; however, to further reduce corrosion, the solution is preferably stored under a layer of liquid paraffin hydrocarbons.
Inventors
- 👤 William Percy Moore
- 👤 James Earl Sansing
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:50
CPC Classifications
C; C05; C05B; C05B1/00; C05B1/06
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
158 words
A process for producing and storing stable ammonium polyphosphate solutions containing at least 0.35% by weight MgO, comprising: a. mixing 24-40% by weight aqueous ammonia with superphosphoric acid containing 66-76% by weight P 2 O 5 and 0.7-2.0% by weight MgO to give a reaction solution having a P 2 O 5 /N weight ratio of 3.6-4.0 and a pH in the range 5.0-5.7; b. maintaining the temperature of the reaction at 50°-100°C.; c. cooling said reaction solution after mixing to a temperature of 25°-35°C.; and d. storing said solution at 25°-35°C. in a carbon steel tank, under a layer of liquid paraffin hydrocarbon having a boiling point of 150°-300°C., and at pH 5.0-5.7, whereby the solution remains stable and does not precipitate solids for at least 250 days, and shows a corrosion rate in said carbon steel tank of less than 1.4 mils per year, said corrosion rate being measured below the air-liquid interface of the solution.
Claim 2
Dependent Claim
158 words
A process for producing and storing stable ammonium polyphosphate solutions containing at least 0.35% by weight MgO, comprising: a. mixing 24-40% by weight aqueous ammonia with superphosphoric acid containing 66-76% by weight P 2 O 5 and 0.7-2.0% by weight MgO to give a reaction solution having a P 2 O 5 /N weight ratio of 3.6-4.0 and a pH in the range 5.0-5.7; b. maintaining the temperature of the reaction at 50°-100°C.; c. cooling said reaction solution after mixing to a temperature of 25°-35°C.; and d. storing said solution at 25°-35°C. in a carbon steel tank, under a layer of liquid paraffin hydrocarbon having a boiling point of 150°-300°C., and at pH 5.0-5.7, whereby the solution remains stable and does not precipitate solids for at least 250 days, and shows a corrosion rate in said carbon steel tank of less than 1.4 mils per year, said corrosion rate being measured below the air-liquid interface of the solution.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein the layer of liquid paraffin hydrocarbon is about 0.05-0.2 inch in thickness.
References Cited (Backward Citations)
US2950961A
Cited
US3305299A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-19 | 1979-07-21 | 1980-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-19 | 1983-07-21 | 1984-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-19 | 1987-07-21 | 1988-01-20 | $7700.00 | Window Closed / Lapsed |