METHOD FOR OBTAINING A UREA-BASED FERTILIZER COMPOSITION COMPRISING A (THIO)PHOSPHORIC ACID TRIAMIDE UREASE INHIBITOR VIA PROVIDING A LIQUID OR SOLID PREMIX WITH SPECIFIC WEIGHT RATIOS

Abstract

Method for obtaining a fertilizer composition comprising (iii) at least one urea-containing fertilizer (1); and (iv) at least one (thio)phosphoric acid triamide (2) according to general formula (I) wherein X.sup.1 is O or S; R.sup.1 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alylaminocarbonyl; R.sup.2 is H, C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; or R.sup.1 and R.sup.2 together with the nitrogen atom linking them define a 5- or 6-membered saturated or unsaturated heterocyclic radical, which optionally comprises 1 or 2 further heteroatoms selected from the group consisting of N, O, and S; and R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; comprising the steps: a) providing a solid and/or liquid premix (P) wherein the premix (P) comprises at least one urea-containing fertilizer (1) and at least one (thio)phosphoric acid triamide (2) in a weight ratio of 1:6 to 400:1 based on the total weight of all urea-containing fertilizers (1) and of all (thio)phosphoric acid triamides (2), wherein at least 85 wt % of the premix (P) (a1) is not a melt; and (a2) is not obtained via melting of any of the at least one urea-containing fertilizer (1) or melting of any of the at least one (thio)phosphoric acid triamide (2); and (a3) is not obtained via dissolving or mixing the at least one (thio)phosphoric acid tri-amide (2) in/with a solvent (S) having a boiling point of less than 100° C., and b) adding the premix (P) to a melt (Q) comprising urea-containing fertilizer (1) by forming a mixture (M) n comprising the at least one urea-containing fertilizer (1) and the at least one (thio)phosphoric acid triamide (2), wherein the residence time of the thus formed mixture (M) before granulation is adjusted such that the at least one (thio)phosphoric acid tri-amide (2) is not or almost not decomposed in the mixture (M); and c) forming solid fertilizer granules by use of the mixture (M) comprising the at least one urea-containing fertilizer (1) and the at least one (thio)phosphoric acid triamide (2).

##STR00001##

Claims

1. Method for obtaining a fertilizer composition comprising (i) at least one urea-containing fertilizer (1); and (ii) at least one (thio)phosphoric acid triamide (2) according to general formula (I) ##STR00015## wherein X.sup.1 is O or S; R.sup.1 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.2-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; R.sup.2 is H, C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; or R.sup.1 and R.sup.2 together with the nitrogen atom linking them define a 5- or 6-membered saturated or unsaturated heterocyclic radical, which optionally comprises 1 or 2 further heteroatoms selected from the group consisting of N, O, and S; and R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; comprising the steps: a) providing a solid and/or liquid premix (P) wherein the premix (P) comprises at least one urea-containing fertilizer (1) and at least one (thio)phosphoric acid triamide (2) in a weight ratio of 1:6 to 400:1 based on the total weight of all urea-containing fertilizers (1) and of all (thio)phosphoric acid triamides (2), wherein at least 85 wt % of the premix (P) (a1) is not a melt; and (a2) is not obtained via melting of any of the at least one urea-containing fertilizer (1) or melting of any of the at least one (thio)phosphoric acid triamide (2); and (a3) is not obtained via dissolving or mixing the at least one (thio)phosphoric acid triamide (2) in/with a solvent (S) having a boiling point of less than 100° C.; and b) adding the premix (P) to a melt (Q) comprising urea-containing fertilizer (1) by forming a mixture (M) comprising the at least one urea-containing fertilizer (1) and the at least one (thio)phosphoric acid triamide (2), wherein the residence time of the thus formed mixture (M) before granulation is adjusted such that the at least one (thio)phosphoric acid triamide (2) is not or almost not decomposed in the mixture (M); and c) forming solid fertilizer granules by use of the mixture (M) comprising the at least one urea-containing fertilizer (1) and the at least one (thio)phosphoric acid triamide (2).

2. A method according to claim 1, wherein the premix (P) as provided in process step a) comprises at least one urea-containing fertilizer (1) and at least one (thio)phosphoric acid triamide (2) in a weight ratio of 4:1 to 50:1.

3. A method according to claim 1, wherein the urea-containing fertilizer (1) contained in the premix (P) has an average particle size in the range of 0.0001 to 60 mm.

4. A method according to claim 1, wherein the urea-containing fertilizer (1) contained in the premix (P) has an average particle size in the range of 0.005 to 4 mm.

5. A method according to claim 1, wherein the premix (P) as provided in process step a) comprises at least one urea-containing fertilizer (1) and at least one (thio)phosphoric acid triamide (2) combined with an amine having a boiling point of more than 100° C.

6. A method according to claim 1, wherein the premix (P) as provided in process step a) comprises at least one urea-containing fertilizer (1) and at least one (thio)phosphoric acid triamide (2) combined with a polymeric polyamine.

7. A method according to claim 1, wherein the premix (P) is liquid.

8. A method according to claim 1, wherein the premix (P) is solid.

9. A method according to claim 1, wherein the premix (P) is provided at a temperature T1 which is not more than the melting point of the highest-boiling (thio)phosphoric acid triamide (2) among the at least one (thio)phosphoric acid triamide (2).

10. A method according to claim 1, wherein the premix (P) is provided at a temperature T1 which is not more than 50° C.

11. A method according to claim 1, wherein the premix (P) is provided at a temperature T1 which is not more than 50° C.

12. A method according to claim 1, wherein the at least one (thio)phosphoric acid triamide (2) is N-n-butylthiophosphoric acid triamide (NBPT).

13. A method according to claim 1, wherein the at least one (thio)phosphoric acid triamide (2) is N-n-propylthiophosphoric acid triamide (NPPT).

14. A method according to claim 1, wherein the at least one (thio)phosphoric acid triamide (2) is a combination of N-n-butylthiophosphoric acid triamide (NBPT) and N-n-propylthiophosphoric acid triamide (NPPT

15. A method according to claim 1, wherein the urea-containing fertilizer (1) is urea.

16. A method according to claim 1, wherein at least 98 wt % of the premix (P) (a1) is not a melt; and (a2) is not obtained via melting of any of the at least one urea-containing fertilizer (1) or melting of any of the at least one (thio)phosphoric acid triamide (2); and (a3) is not obtained via dissolving or mixing the at least one (thio)phosphoric acid triamide (2) in/with a solvent (S) having a boiling point of less than 100° C.

17. The fertilizer composition obtained or obtainable by a method according to claim 1.

Description

EXAMPLES

[0444] Materials:

[0445] Urease Inhibitors:

[0446] Urease inhibitor “U1” was obtained from BASF SE. Composition: [0447] 18.75 wt.-% N-butylphosphorothioic triamide (NBPT, CAS-no.: 94317-64-3) [0448] 6.25 wt.-% N-propylphosphorothioic triamide (NPPT, CAS-no.: 916809-14-8)

[0449] LTM is the technical mixture (with a 100% concentration of NxPT) containing 25% NPPT and 75% NBPT.

[0450] LFG is polyethyleneimine with a weight average molecular weight of 800 g/mol as measured by GPC (dry substance, at pH 4.5)

[0451] Limus formulation is obtained by mixing the LTM (25% pure NxPT) was mixed with 15% DMSO, 5% LFG, and ad100% propylene glycol. The mixture was stirred until complete dissolution of the solid and analyzed for NxPT content (by HPLC), viscosity at 20° C. with a shear rate of 100 sec-1, dissolution (2%) in water and pH.

[0452] Fertilizers:

[0453] Urea (Piagran 46) was obtained from SKW Piesteritz.

[0454] Urea granules were milled to <0.5 mm. Urea powder was mixed with NBPT and NPPT powder to form a premix.

Example 1

[0455] a) Premix 1: Urea granules were milled to <0.5 mm. Urea powder was mixed with Limus formulation in a ratio of 1:1 urea powder to solution, forming a suspension. [0456] b) Premix 2: Urea granules were milled to <0.5 mm. Urea powder was mixed with Limus formulation in a ratio of 2:1 urea powder to solution, forming a paste. [0457] c) Premix 3: Urea granules were milled to <0.5 mm. Urea powder was mixed with Limus formulation in a ratio of 10:1 urea powder to solution, forming a free flowing powder.

TABLE-US-00001 TABLE 1 Data of Example 1 A.i. content measured (NBPT + NPPT) using Milled Limus HLPC (method urea formulation DIN EN 16651) (g) (g) (wt %) Premix 1 10.0 10.3 13.5 Premix 2 10.0 5.0 8.5 Premix 3 15.0 1.6 2.4

Example 2

[0458] d) Premix 4: Urea granules were milled to <0.5 mm. Urea powder was mixed with a solution of NBPT and NPPT in polyethyleneimine (40 wt %) in a ratio of 1:1 urea powder to solution. forming a viscous liquid. [0459] e) Premix 5: Urea granules were milled to <0.5 mm. Urea powder was mixed with a solution of NBPT and NPPT in polyethyleneimine (40 wt %) in a ratio of 2:1 urea powder to solution. forming a paste. [0460] f) Premix 6: Urea granules were milled to <0.5 mm. Urea powder was mixed with a solution of NBPT and NPPT in polyethyleneimine (40 wt %) in a ratio of 10:1 urea powder to solution. forming a free flowing powder.

TABLE-US-00002 TABLE 2 Data of Example 2 A.i. content measured (NBPT + NBPT/NPPT NPPT) using Milled polyethyleneimine HLPC (method urea solution DIN EN 16651) (g) (g) (wt %) Premix 4 5.0 5.1 20.1 Premix 5 5.0 2.7 13.3 Premix 6 10.0 1.2 4.2

Example 3

[0461] Stainless steel pan was filled with 500 g urea and under continuous stirring heated to 135° C. After all urea was molten, the respective amount of premix was added and stirred in for 30 seconds. Afterwards, the molten urea was poured onto a stainless-steel tray and let cool down for 30 minutes at room temperature. Next, the solidified urea was broken up in pieces and 2×15 g sample, each dissolved in 100 mL water, were analyzed using HPLC method DIN EN 16651 and the measured a.i. concentrations were averaged and indicated in the right column (a.i. recovery).

TABLE-US-00003 Premix Urea melt Target a.i. Measured a.i. A.i. Premix amount amount Concentration Concentration Recovery Exp. used (g) (g) (wt %) (wt %) (%) S1 Premix 1 2.13 500 0.057 0.055 95.6 S2 Premix 2 3.23 500 0.055 0.052 95.1 S3 Premix 3 11.53 500 0.054 0.052 96.3 S4 Premix 4 1.33 500 0.053 0.051 96.2 S5 Premix 5 1.94 500 0.052 0.051 98.7 S6 Premix 6 6.16 500 0.051 0.048 94.4

[0462] The results above show that the TPT contained in the premix does not decompose or degrade during the melting process, thus remains stable or stabilized during the melting process.