HIGH NITROGEN LIQUID FERTILIZER
The present invention is directed to liquid fertilizer composition having a high nitrogen content comprising an aqueous mixture of a urea-formaldehyde resin and a nitrogen fertilizer source selected from the group consisting of urea, ammonium nitrate, and a mixture of urea and ammonium nitrate, wherein the liquid fertilizer possess surprisingly depressed freeze points and salt-out temperatures.
1 . An aqueous nitrogen fertilizer solution comprising a mixture of a urea-formaldehyde resin and a nitrogen fertilizer source selected from the group consisting of urea, ammonium nitrate and a mixture of urea and ammonium nitrate.
2 . The aqueous nitrogen fertilizer solution of claim 1 wherein the urea-formaldehyde resin is prepared by reacting urea, formaldehyde and optionally ammonia in water under an alkaline reaction condition to yield an aqueous urea-formaldehyde resin solution.
3 . The aqueous nitrogen fertilizer solution of claim 2 wherein the urea-formaldehyde resin is prepared by reacting urea, formaldehyde and ammonia at a formaldehyde/urea/ammonia mole ratio of 1-4/1/:0.5-1.
4 . The aqueous nitrogen fertilizer solution of claim 2 wherein the urea-formaldehyde resin is prepared by reacting urea, formaldehyde and ammonia at a formaldehyde/urea/ammonia mole ratio of 0.6-1/1/0.25-0.35.
5 . The aqueous nitrogen fertilizer solution of claim 3 wherein the urea-formaldehyde resin is prepared by reacting a solution of urea, formaldehyde and ammonia at a temperature from 80° C. to 95° C. and a pH from 7.5 to 10.5 for 45 to 120 minutes.
6 . The aqueous nitrogen fertilizer solution of claim 4 wherein the urea-formaldehyde resin is prepared by reacting a solution of urea, formaldehyde and ammonia at a temperature from 80° C. to 95° C. and a pH from 7.5 to 10.5 for 45 to 120 minutes.
7 . The aqueous nitrogen fertilizer solution of claim 3 wherein the urea-formaldehyde resin has a cyclic urea content, based on 100% resin solids, of greater than 20% by weight.
8 . The aqueous nitrogen fertilizer solution of claim 7 wherein the urea-formaldehyde resin has a cyclic urea content, based on 100% resin solids, of greater than 40% by weight.
9 . The aqueous nitrogen fertilizer solution of claim 8 wherein the urea-formaldehyde resin has a free urea content, based on 100% resin solids, of less than 10% by weight.
10 . The aqueous nitrogen fertilizer solution of claim 4 wherein the urea-formaldehyde resin has a cyclic urea content, based on 100% resin solids, of 14 to 20% by weight.
11 . The aqueous nitrogen fertilizer solution of claim 3 prepared by blending an aqueous urea-ammonium nitrate solution having a nitrogen content from 28 to 32% by weight with an aqueous solution of a urea-formaldehyde resin.
12 . The aqueous nitrogen fertilizer solution of claim 4 prepared by blending an aqueous urea-ammonium nitrate solution having a nitrogen content from 28 to 32% by weight with an aqueous solution of a urea-formaldehyde resin.
13 . The aqueous nitrogen fertilizer solution of claim 3 wherein an aqueous urea-formaldehyde resin solution (UF) is mixed with a nitrogen fertilizer source selected from the group consisting of an aqueous solution of urea (U), an aqueous solution of ammonium nitrate (AN) and an aqueous solution of urea-ammonium nitrate (UAN) in a weight ratio (UF:U, UF:AN or UF:UAN) of 90:10 to 10:90.
14 . The aqueous nitrogen fertilizer solution of claim 4 wherein an aqueous urea-formaldehyde resin solution (UF) is mixed with a nitrogen fertilizer source selected from the group consisting of an aqueous solution of urea (U), an aqueous solution of ammonium nitrate (AN) and an aqueous solution of urea-ammonium nitrate (UAN) in a weight ratio (UF:U, UF:AN or UF:UAN) of 90:10 to 10:90.
15 . The aqueous nitrogen fertilizer solution of claim 3 wherein an aqueous urea-formaldehyde resin solution (UF) is mixed with a nitrogen fertilizer source selected from the group consisting of an aqueous solution of urea (U), an aqueous solution of ammonium nitrate (AN) and an aqueous solution of urea-ammonium nitrate (UAN) in a weight ratio (UF:U, UF:AN or UF:UAN) of 70:30 to 30:70.
16 . The aqueous nitrogen fertilizer solution of claim 4 wherein an aqueous urea-formaldehyde resin solution (UF) is mixed with a nitrogen fertilizer source selected from the group consisting of an aqueous solution of urea (U), an aqueous solution of ammonium nitrate (AN) and an aqueous solution of urea-ammonium nitrate (UAN) in a weight ratio (UF:U, UF:AN or UF:UAN) of 70:30 to 30:70.
17 . The aqueous nitrogen fertilizer solution of claim 3 wherein an aqueous urea-formaldehyde resin solution (UF) is mixed with a nitrogen fertilizer source selected from the group consisting of an aqueous solution of urea (U), an aqueous solution of ammonium nitrate (AN) and an aqueous solution of urea-ammonium nitrate (UAN) in a weight ratio (UF:U, UF:AN or UF:UAN) of 30:70 to 50:50.
18 . The aqueous nitrogen fertilizer solution of claim 15 wherein the aqueous urea-formaldehyde resin solution has a solid concentration of above 70% by weight.
19 . The aqueous nitrogen fertilizer solution of claim 16 wherein the aqueous urea-formaldehyde resin solution has a solid concentration of above 70% by weight.
20 . The aqueous nitrogen fertilizer solution of claim 17 wherein the aqueous urea-formaldehyde resin solution has a solid concentration of above 70% by weight.