Highly available particulate controlled release nitrogen fertilizer
US6048378A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 13, 1998 |
| Grant date | Apr 11, 2000 |
| Priority date | — |
| Expiry date | Aug 13, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC05G5/40
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A method preparing controlled release nitrogen in particulate fertilizers which exhibit single growing season availabilities to plants of about 80 percent or higher. The method utilizes relatively low urea and ammonia to formaldehyde mol ratios of about 1.7 urea to 0.1 ammonia to 1 formaldehyde to assure high conversions to controlled release nitrogen with low free ureas, and carefully controlled elevated temperatures, acid dehydration condensation catalyst concentrations and short dehydration reaction times of about 2-4 minutes to provide effective conversion of hydroxymethyl nitrogen compounds by dehydration condensation reaction to controlled release methylene nitrogen compounds. Quick neutralization of the dehydration catalyst in a turbulent mixing reactor minimizes the formation of undesirable methylene nitrogen polymers which are hot water insoluble and unavailable to plants in a single growing season.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.