| 摘要 |
<p>A new method of preparing a new aminoureaformaldehyde fertilizer composition which exhibits high cold water insoluble nitrogen (CWIN) levels and high Availability Indices (AI). The method utilizes the discoveries that ammonia compounds, usually ammonium salts, inhibit the urea-formaldehyde polymerization reaction and decrease the formation of hot water insoluble nitrogen (HWIN), and that the ammonium compounds take part in the reaction to form controlled release compounds which are both cold water soluble and insoluble. The process is carried out at elevated temperatures between 60 and 125 DEG F., so that it may be completed in an order of magnitude less time than either the dilute or concentrated conventional commercial ureaform processes, requiring between 2 and 20 minutes for completion. In the process, between 3 and 25 percent of the total nitrogen is supplied as ammonia nitrogen with the remainder from urea, respective formaldehyde to urea to ammonia mol ratio is 1.0, between 1.0 and 2.0 and between 0.05 and 1.0. The new fertilizer composition is produced directly as semi-dry granules, the drying of which may be completed in a conventional dryer such as a fluid bed, and exhibits urea conversions to CWIN between 50 and 85 percent with AIs higher than 45. The method is most effectively performed batchwise in a high intensity mixer-reactor-granulator comprising a cylindrical pan rotating around a near-vertical axis and containing a small diameter mixer rotating at a high speed relative to that of the pan.</p> |
