Urea-based blend composition and method for the manufacture thereof

Abstract

The invention relates to a particulate urea-based blend composition comprising a urea-based compound in particulate form and one or more components in particulate form, selected from the group of nitrates, phosphates, sulphates and chlorides, and a urease inhibitor of the type phosphoric triamide, and a magnesium sulphate, wherein the urea-based blend composition is further characterized in that it comprises an alkaline or alkaline-forming compound, selected from the group of calcium oxide, zinc oxide, magnesium oxide, calcium carbonate, and mixtures thereof. The composition according to the invention has improved properties for reducing ammonia loss by urease activity in the soil and is in particular suitable as a fertilizer. The invention further relates to a method for the manufacture of said urea-based blend composition, as well as to a composition of kit of parts comprising an amount of a) magnesium sulphate; b) a urease inhibitor of the type phosphoric triamide, preferably N-(n-butyl) thiophosphoric triamide (nBTPT); c) an alkaline or alkaline-forming compound, selected from the group of calcium oxide, zinc oxide, magnesium oxide, calcium carbonate, and mixtures thereof, and d) optionally, one or more anti-caking and/or moisture-repellent and/or anti-dust compounds.

Claims

1. A particulate urea-based blend composition comprising: 40 to 99 weight % of an urea-based compound in particulate form; 1 to 60 weight % of at least one component in particulate form selected from the group consisting of nitrates, phosphates, sulphates and chlorides; 0.0001 to 1 weight % of a phosphoric triamide urease inhibitor; 0.02 to 1 weight % of magnesium sulphate; and an amount of an alkaline or alkaline-forming compound selected from the group consisting of calcium oxide, zinc oxide, magnesium oxide, calcium carbonate, and mixtures thereof, such that the weight ratio of the alkaline or alkaline-forming compound to magnesium sulphate ranges from 1:20 to 1:2; adding up to 100 weight %, being the total weight of the composition.

2. The urea-based blend composition according to claim 1, wherein the urease inhibitor is present at a level of 0.02 to 0.2 weight % relative to the total weight of the urea-based blend composition.

3. The urea-based blend composition according to claim 2, wherein the urease inhibitor is N-(n-butyl) thiophosphoric triamide (nBTPT).

4. The urea-based blend composition according to claim 2, wherein the level of urease inhibitor is from 0.03 to 0.06 weight %.

5. The urea-based blend composition according to claim 1, wherein the weight ratio of alkaline or alkaline-forming compound to magnesium sulphate ranges from 1:15 to 1:2.

6. The urea-based blend composition according to claim 5, wherein the weight ratio of alkaline or alkaline-forming compound to magnesium sulphate ranges from 1:10 to 1:2.

7. The urea-based blend composition according to claim 1, comprising urea in particulate form either coated or melt-mixed with a phosphoric triamide urease inhibitor, ammonium phosphate (MAP or DAP) in particulate form, potassium chloride (MOP), and a magnesium sulphate.

8. The urea-based blend composition according to claim 7, wherein the urease inhibitor is N-(n-butyl)-thiophosphoric triamide.

9. The urea-based blend composition according to claim 1, comprising urea in particulate form either coated or melt-mixed with a phosphoric triamide urease inhibitor, ammonium sulphate (AS) in particulate form, and a magnesium sulphate.

10. The urea-based blend composition according to claim 9, wherein the urease inhibitor is N-(n-butyl)-thiophosphoric triamide.

11. The urea-based blend composition according to claim 1, wherein the magnesium sulphate is present in the composition at a level of 0.05 to 1 weight %, relative to the total weight of the composition.

12. The urea-based blend composition according to claim 1, wherein the magnesium sulphate is selected from the group consisting of anhydrous, mono-, di-, tri-, tetra-, penta-, hexa-, heptahydrate, and mixtures thereof.

13. The urea-based blend composition according to claim 1, wherein the phosphoric triamide urease inhibitor is a compound of formula I: ##STR00005## wherein: X is oxygen or sulphur; R.sub.1 is alkyl, cycloalkenyl, aralkyl, aryl, alkenyl, alkynyl, or cycloalkyl; R.sub.2 is hydrogen, alkyl, cycloalkenyl, aralkyl, aryl, alkenyl, alkynyl, or cycloalkyl, or R.sub.1 and R.sub.2 together may form an alkylene or alkenylene chain which may optionally include one or more heteroatoms of divalent oxygen, nitrogen or sulphur completing a 4, 5, 6, 7, or 8 membered ring system; R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are individually hydrogen or alkyl having 1 to 6 carbon atoms, and alkyl, cycloalkenyl, aralkyl, aryl, alkenyl, alkynyl, and cycloalkyl refer to compounds having from 1 to 10 carbon atoms.

14. The urea-based blend composition according to claim 1, wherein the urease inhibitor is N-(n-butyl) thiophosphoric triamide (nBTPT).

15. The urea-based blend composition according to claim 1, wherein the alkaline or alkaline-forming compound is magnesium oxide.

16. The urea-based blend composition according to claim 1, wherein the urea-based compound is selected from urea, urea calcium sulphate (UCaS), urea calcium nitrate (UCaN), urea magnesium nitrate (UMgN), urea calcium phosphate (UCaP), urea magnesium phosphate (UMgP), urea superphosphate (USP), urea calcium ammonium nitrate (UCAN), urea ammonium sulphate (UAS), urea ammonium phosphate (UAP), urea potassium salts (UK), or mixtures thereof.

17. The urea-based blend composition according to claim 1, wherein the at least one component in particulate form is selected from the group consisting of ammonium nitrate, calcium nitrate, calcium ammonium nitrate, sodium nitrate, ammonium sulphate nitrate, potassium ammonium nitrate, ammonium phosphate, calcium bis(dihydrogen orthophosphate), super phosphate, triple superphosphate (TSP), rock phosphate, potassium sulphate, potassium magnesium sulphate, ammonium sulphate (AS), potassium chloride (MOP), and mixtures thereof.

18. The urea-based blend composition according to claim 1 wherein the composition contains: 40 to 99 weight % of a urea-based compound in particulate form; 1 to 60 weight % of one or more components in particulate form, selected from the group consisting of nitrates, phosphates, sulphates and chlorides; 0.03 to 0.06 weight % of nBTPT; 0.05 to 0.1 weight % of a magnesium sulphate; and 0.015 to 0.03 weight % of magnesium oxide, adding up to 100 weight %, being the total weight of the composition.

19. A method comprising treating a soil with the particulate urea-based blend composition as claimed in claim 1 as a fertilizer.

20. A method for the manufacture of a particulate urea-based blend composition according to claim 1, the method comprising the steps of: 1) providing 40 to 99 weight % of the urea-based compound in particulate form; 2) providing 1 to 60 weight % of the at least one component in particulate form selected from the group consisting of nitrates, phosphates, sulphates and chlorides; 3) providing 0.02 to 1 weight %, relative to the total weight of the composition, of a magnesium sulphate; 4) providing 0.0001 to 1 weight %, relative to the total weight of the composition, of a phosphoric triamide urease inhibitor; 5) providing an amount of the alkaline or alkaline-forming compound, selected from the group consisting of calcium oxide, zinc oxide, magnesium oxide, calcium carbonate, and mixtures thereof, such that the weight ratio of said alkaline or alkaline-forming compound to magnesium sulphate ranges from 1:20 to 1:2; 6) optionally, providing coating material wherein the coating material is able to increase at least the anticaking and/or moisture repellence and/or anti-dust properties of said urea-based blend composition; and 7) mixing the components provided in steps 1), 2), 3), 4), 5) and 6) in any order.

21. The method according to claim 20, wherein the urease inhibitor is N-(n-butyl) thiophosphoric triamide.

22. A kit of parts, comprising an amount of: a) a phosphoric triamide urease inhibitor; b) a magnesium sulphate, such that the weight ratio of the phosphoric triamide urease inhibitor to magnesium sulphate ranges from 1:20 to 1:1; c) an alkaline or alkaline-forming compound, selected from the group consisting of calcium oxide, zinc oxide, magnesium oxide, calcium carbonate, and mixtures thereof, such that the weight ratio of said alkaline or alkaline-forming compound to magnesium sulphate ranges from 1:20 to 1:2; and d) optionally, at least one anti-caking and/or moisture-repellent and/or anti-dust compounds.

23. The kit according to claim 22, wherein the urease inhibitor is N-(n-butyl) thiophosphoric triamide.

24. The kit according to claim 22, wherein the weight ratio of the phosphoric triamide urease inhibitor to magnesium sulphate ranges from 1:10 to 1:1.

25. The kit according to claim 22, wherein the alkaline or alkaline-forming compound is magnesium oxide.

26. A method for improving the stability of a phosphoric triamide urease inhibitor in a particulate urea-based blend composition comprising a urea-based compound in particulate form, at least one component in particulate form selected from the group consisting of nitrates, phosphates, sulphates and chlorides and said urease inhibitor, the method comprising adding a stabilizer to the composition, the stabilizer comprising from 0.02 to 1 weight % of a magnesium sulphate, relative to the total weight of the composition, and an amount of alkaline or alkaline-forming compound selected from the group consisting of calcium oxide, zinc oxide, magnesium oxide, calcium carbonate, and mixtures thereof, such that the weight ratio of said alkaline or alkaline-forming compound to magnesium sulphate ranges from 1:20 to 1:2.

27. The method of claim 26, wherein the urease inhibitor is N-(n-butyl)-thiophosphoric triamide.

Description

DESCRIPTION OF FIGURES

(1) FIG. 1. Ammonia release of a YaraVera® Amidas product comprising 462 ppm nBTPT, treated with several stabilizers (see Table 1).

(2) FIG. 2A. Stability of nBTPT on a YaraVera® Amidas product comprising 462 ppm nBTPT in plastic containers open to air at room temperature after 40 days [A=no stabilizer; B=CaO (2541 ppm); C=MgSO.sub.4 99.5% purity (4957 ppm)].

(3) FIG. 2B. Stability of nBTPT on a YaraVera® Amidas product comprising 462 ppm nBTPT, in bags at 40° C. [A=no stabilizer; B=CaO (2541 ppm); C=MgSO.sub.4 99.5% purity (4957 ppm)] after 8 days.

(4) FIG. 3. Stability of nBTPT on a YaraVera® Amidas product comprising 462 ppm nBTPT using different grades and forms of MgSO.sub.4 and Na.sub.2SO.sub.4, stored in open plastic containers at room temperature for 21 days. [A=no stabilizer; B=CaO (2541 ppm); C=MgSO.sub.4 99.5% purity (4957 ppm); D=MgSO.sub.4 99.999% purity (4957 ppm); E=MgSO.sub.4.7H.sub.2O (10163 ppm; F=Na.sub.2SO.sub.4 (5849 ppm]

(5) FIG. 4. Stability of nBTPT on a YaraVera® Amidas product comprising 462 ppm nBTPT using different MgSO.sub.4/MgO combinations [A=no stabilizer; B=CaO (2310 ppm); C=MgO (212 ppm); D=MgSO.sub.4>98% grade (4620 ppm); E=MgSO.sub.4>98% grade (924 ppm)/MgO (212 ppm)]

EXPERIMENTAL

(6) 1. Volatilization Measurements (Ammonia Release 2 L Diffusion Kit)

(7) 200 g of UAS product, treated with nBTPT/stabilizer are put in a 2 L plastic container. Through the lid, a Draeger tube is placed for the measurement of vol % ammonia. The Draeger tube turns from yellow to bleu/purple when ammonia is absorbed by the tube. The amount of vol % ammonia released can be followed in time.

(8) 2. nBTPT Measurements

(9) For lab scale experiments, 1.2 kg of solid fertilizer material was added to a lab scale drum. In a next step, the nBTPT/stabilizer material was slowly added. A residence time of 10 minutes was applied and the rotating speed of the drum was consequently the same in each experiment. In case a moisture-repellent coating was added, a nebulizer was used and depending on the order of addition, the moisture-repellent coating was added before or after addition of the nBTPT material. Before use, the moisture-repellent coating was preheated to 80° C. Larger scale experiments with amounts up to 40 kg of fertilizer material were performed in a concrete mixer.

(10) The samples were stored under several conditions, dependent on the type of samples: Bagged at room temperature (18-25° C.) Bagged at 40° C. Open to air at room temperature (18-25° C.)

(11) 3. HPLC Analysis of nBTPT-Content

(12) HPLC analysis of nBTPT is done as described in the procedure CEN 15688-2007.

(13) 4. Products

(14) UAS was obtained from Yara as granules YaraVera® Amidas 40-0-0 (product code PA421X).

(15) Solid N-(n-butyl)thiophosphoric triamide was obtained from Sunfit Chemical Co. (China) (CAS-Nr. 94317-64-3), as a white crystalline solid with a melting point of 58-60° C.

(16) MgO technical grade was obtained from Mannekus & Co B. V., Schiedam, The Netherlands (dp(50)=27 μm, +/−90% purity, 2-2.9% CaO, 1.1% SiO2).

(17) CaO technical grade was obtained from VWR International, Oud-Heverlee, Belgium (91.3% pure, 2.7% CaCO.sub.3 and 6% Ca(OH).sub.2), dp(50)=22 μm).

(18) CaCO.sub.3 (limestone powder) was obtained from Nordkalk AB, Finland (98.5% pure, dp(50)=7 μm).

(19) CaSO.sub.4 anhydrous was obtained from Alfa Aesar, Haverhill, USA.

(20) MgSO.sub.4 anhydrous, 99.999%, was obtained from Alfa Aesar, Haverhill, USA.

(21) MgSO.sub.4 anhydrous, >99.5%, was obtained from Alfa Aesar, Haverhill, USA. MgSO.sub.4 anhydrous, >98%, was obtained from Ekmekciogullari, Turkey.

(22) MgSO.sub.4.7H.sub.2O, >99.5%, was obtained from Merck KGaA, Darmstadt, Germany.

(23) Coating: Moisture-repellent (MR) coating was made according to EP 0768993 A1 (Norsk Hydro ASA) by mixing about 28 weight % of wax, about 68 weight % of oil and about 4 weight % of a resin, applied in an amount of about 0.1-0.5 weight % to the fertilizer. It will be referred herein as NH-coating.

PRIOR ART EXPERIMENT

(24) WO2017/168288 discloses several compositions comprising urea, a phosphate component and various amounts of MgSO.sub.4. Prevention of the degradation of the urease inhibitor used (NBPT+NPPT)* is not effective with amounts of MgSO.sub.4 smaller than 0.25 g (1.25 weight %).

(25) TABLE-US-00001 Example 3, 0.04% of NBPT + 0.5 g MgSO.sub.4 effective Sample 2 &3 NPPT, 10 g urea, (2.5 weight %) prevention 10 g Urea + of ammonia 10 g TSP*/DAP release Example 4, 0.04% of NBPT + 0.25 g MgSO.sub.4 effective Sample 3 NPPT, 10 g urea, (1.25 weight %) prevention 10 g Urea + of ammonia 10 g TSP/DAP release Example 6 0.04% of NBPT + various amounts of prevention Samples 1, NPPT, 10 g urea, MgSO.sub.4 of ammonia 2, 3, 4 & 5 10 g urea + 0.5 g (2.5 weight %) release is not 10 g DAP 0.25 g (1.25 weight %) effective with 0.18 g (0.9 weight %) amounts 0.11 g (0.55 weight %) smaller than 0.05 g (0.25 weight %) 0.25 g (1.25 weight %) *TSP = triple super phosphate *NBPT = N-(n-butyl)thiophosphoric acid triamide = nBTPT *NPPT = N-(n-propyl)thiophosphoric acid triamide

Experiment 1 (Ammonia Release)

(26) Experiment 1 defines the problem. FIG. 1 shows the ammonia release of a YaraVera® Amidas product comprising 462 ppm nBTPT, treated with several stabilizers. The numbers between brackets represent, for each stabilizer compound, the weight ratio of the said stabilizer compound compared to nBTPT.

(27) TABLE-US-00002 TABLE 1 Ammonia release with different stabilizers Example Stabilizer composition A (prior art) MgO (4.3) B (prior art) CaO-G-0554 (5.5) C (prior art) MgO (0.86) D (prior art) none E (prior art) CaCO.sub.3 (9.98) F (prior art) CaSO.sub.4 (12.1) G MgSO.sub.4 (10.7)

(28) Although compounds such as MgO and CaO are mentioned in the prior art document WO2017042194 (Yara International, 2017) as most effective stabilizers for nBTPT in the presence of a urea ammonium sulphate material, these compounds are observed as producing ammonia in the presence of said material, which is an unwanted effect of these stabilizers. Only without stabilizer, and with MgSO.sub.4 and with CaSO.sub.4, there is no ammonia release.

Experiment 2

(29) This experiment was conducted to show the difference between the beneficial effect of the addition of an alkaline or alkaline-forming inorganic or organic compound (CaO—prior art) and MgSO.sub.4 (VWR grade 99.5%) to UAS on the stability of nBTPT in the presence of UAS open to the air at room temperature (FIG. 2A) and in bags at elevated temperature (FIG. 2B). As can be seen, the stabilizing effect of MgSO.sub.4 is comparable with the effect of the prior art compound (CaO), but no ammonia is generated (as shown in FIG. 1).

Experiment 3 (Different Grades)

(30) This experiment shows the effect of the addition of different grades and forms of MgSO.sub.4 and also another sulfate, Na.sub.2SO.sub.4, compared to the prior art compound CaO for open to air storage conditions at room temperature (FIG. 3). All MgSO.sub.4 grades give a comparable nBTPT stability on the YaraVera® Amidas product. This experiment shows that the stabilizing effect of MgSO.sub.4 on nBTPT on UAS is not 100% based on a pH effect (alkaline pH 8.5 for MgSO.sub.4 99.5% versus acidic pH 6.1 for MgSO.sub.4 99.999%) and also not 100% based on the waterbinding effect of anhydrous MgSO.sub.4 as MgSO.sub.4.7H.sub.2O delivers similar nBTPT stability. Na.sub.2SO.sub.4 actually has a negative effect on the stability of nBTPT. This shows the unique stabilizing effect of magnesium sulphate.

Experiment 4 (Effect of Addition of Oxides and Synergetic Effect of MgSO.SUB.4 .and MgO)

(31) This experiment shows the effect of the addition of a small amount of oxide to the stabilizer. Small amounts of MgSO.sub.4, which have little effect, become very effective in a combination with MgO (see D versus F). The effect is synergetic (see C+D versus F) and not additive. There is almost no difference in stability depending on the method of combining the components of the stabilizer composition (i.e. adding the components one by one in any order/making a pre-mix of the components and adding the pre-mix to UAS). MgO was found more effective than CaO, but it is assumed that any alkaline or alkaline-forming compound, selected from the group of calcium oxide, zinc oxide, magnesium oxide, calcium carbonate, and mixtures thereof, is effective.

Aspects of the Invention

(32) Further to the description above and the appended claims, the following aspects of the invention are considered:

(33) Aspect 1. A solid, particulate urea-based blend composition comprising a urea-based compound in particulate form, one or more components in particulate form, selected from the group of nitrates, phosphates, sulphates and chlorides, and a urease inhibitor of the type phosphoric triamide, wherein the urea-based blend composition is further characterized in that it comprises a magnesium sulphate.

(34) Aspect 2. The urea-based blend composition according to aspect 1, characterized in that the magnesium sulphate is present in the composition at a level of 0.0001 to 5 weight %, preferable 0.02 to 1 weight %, most preferably 0.05 to 1 weight %, relative to the total weight of the composition.

(35) Aspect 3. The urea-based blend composition according to any one of aspects 1 to 2, wherein the magnesium sulphate is selected from the group of anhydrous, mono-, di-, tri-, tetra-, penta-, hexa-, heptahydrate, and mixtures thereof.

(36) Aspect 4. The urea-based blend composition according to aspect 3, wherein the magnesium sulphate has a purity of >70%, preferably >80%, more preferably >90%, most preferably >99%.

(37) Aspect 5. The urea-based blend composition according to any one of aspects 1 to 4, characterized in that the urease inhibitor of the type phosphoric triamide is a compound of formula I:

(38) ##STR00004##

(39) wherein:

(40) X is oxygen or sulphur;

(41) R.sub.1 is alkyl, cycloalkenyl, aralkyl, aryl, alkenyl, alkynyl, or cycloalkyl;

(42) R.sub.2 is hydrogen, alkyl, cycloalkenyl, aralkyl, aryl, alkenyl, alkynyl, or cycloalkyl, or R.sub.1 and R.sub.2 together may form an alkylene or alkenylene chain which may optionally include one or more heteroatoms of divalent oxygen, nitrogen or sulphur completing a 4, 5, 6, 7, or 8 membered ring system; and

(43) R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are individually hydrogen or alkyl having 1 to 6 carbon atoms, and alkyl, cycloalkenyl, aralkyl, aryl, alkenyl, alkynyl, and cycloalkyl refer to compounds having from 1 to 10 carbon atoms, preferably from 1 to 6 carbon atoms.

(44) Aspect 6. The urea-based blend composition according to any one of aspects 1 to 5, wherein the urease inhibitor is N-(n-butyl) thiophosphoric triamide (nBTPT).

(45) Aspect 7. The urea-based blend composition according to any one of aspects 1 to 6, wherein the urease inhibitor, in particular N-(n-butyl) thiophosphoric triamide (nBTPT) is present at a level of 0.0001 to 1 weight %, preferable 0.02 to 0.2% weight %, most preferably 0.03 to 0.06 weight %, relative to the total weight of the urea-based blend composition.

(46) Aspect 8. The urea-based blend composition according to any one of aspects 1 to 7, wherein the weight ratio of urease inhibitor of the type phosphoric triamide to magnesium sulphate ranges from 1:20 to 1:1, preferably from 1:15 to 1:1, more preferably from 1:10 to 1:1.

(47) Aspect 9. The urea-based blend composition according to any one of aspects 1 to 8, wherein the urease inhibitor of the type phosphoric triamide is applied onto the urea-based blend composition in liquid or in particulate form, is melt-mixed with a component of the urea-based blend composition, or a combination thereof.

(48) Aspect 10. The urea-based blend composition according to any one of aspects 1 to 9, wherein the urea-based blend composition further comprises an alkaline or alkaline-forming compound, selected from the group of calcium oxide, zinc oxide, magnesium oxide, calcium carbonate, and mixtures thereof.

(49) Aspect 11. The urea-based blend composition according to aspect 10, wherein the weight ratio of alkaline or alkaline-forming compound to magnesium sulphate ranges from 1:20 to 1:2, preferably from 1:15 to 1:2, more preferably from 1:10 to 1:2.

(50) Aspect 12. The urea-based blend composition according to any one of aspects 1 to 11, characterized in that the urea-based blend composition further comprises anti-caking and/or moisture-repellent and/or anti-dust material, preferably applied as a coating to the urea ammonium particulate material.

(51) Aspect 13. The urea-based blend according to aspect 12, wherein the anticaking and/or moisture-repellent coating comprising at least a non-polar material, in particular a liquid organic material, such as an oil, wax, resin or the like and any mixture thereof and is present in the composition at a level of 0.0001 to 1 weight %, preferable 0.02 to 0.5 weight %, most preferably 0.1 to 0.2 weight %, relative to the total weight of the composition.

(52) Aspect 14. The urea-based blend composition according to any one of aspects 1 to 13, wherein the urea-based compound is selected from the group of urea, urea calcium sulphate (UCaS), urea calcium nitrate (UCaN), urea magnesium nitrate (UMgN), urea calcium phosphate (UCaP), urea magnesium phosphate (UMgP), urea superphosphate (USP), urea calcium ammonium nitrate (UCAN), urea ammonium sulphate (UAS), urea ammonium phosphate (UAP), urea potassium salts (UK), or mixtures thereof.

(53) Aspect 15. The urea-based blend composition according to any one of aspects 1 to 14, wherein the one or more components in particulate form, selected from the group of nitrates, phosphates, sulphates and chlorides are selected from the group of: ammonium nitrate, calcium nitrate, calcium ammonium nitrate, sodium nitrate, ammonium sulphate nitrate, potassium ammonium nitrate, ammonium phosphate, such as mono-ammonium phosphate (MAP) and di-ammonium phosphate (DAP), calcium bis(dihydrogen orthophosphate), super phosphate, triple superphosphate (TSP), rock phosphate, potassium sulphate, potassium magnesium sulphate, ammonium sulphate (AS), potassium chloride (MOP), or mixtures thereof.

(54) Aspect 16. The urea-based blend composition according to any one of aspects 1 to 15, wherein the composition comprises from about 1 to 60 weight % of one or more components in particulate form, selected from the group of nitrates, phosphates, sulphates and chlorides.

(55) Aspect 17. The urea-based blend composition according to any one of aspects 1 to 16, characterized in that the average particle size (dp50) of the particulate components is between 1 mm and 5 cm, as determined by mesh sieve screening.

(56) Aspect 18. The urea-based blend composition according to any one of aspects 1 to 17, wherein the composition contains: 40 to 99 weight % of a urea-based compound in particulate form; 1 to 60 weight % of one or more components in particulate form, selected from the group of nitrates, phosphates, sulphates and chlorides; 0.03 to 0.06 weight % of nBTPT; 0.05 to 0.1 weight % of a magnesium sulphate; and 0.015 to 0.03 weight % of magnesium oxide, adding up to 100 weight %, being the total weight of the composition.

(57) Aspect 19. The urea-based blend composition according to any one of aspects 1 to 18, comprising urea in particulate form either coated or melt-mixed with a urease inhibitor of the type phosphoric triamide, in particular N-(n-butyl) thiophosphoric triamide (nBTPT), ammonium phosphate (MAP or DAP) in particulate form, potassium chloride (MOP), and a magnesium sulphate.

(58) Aspect 20. The urea-based blend composition according to any one of aspects 1 to 19, comprising urea in particulate form either coated or melt-mixed with a urease inhibitor of the type phosphoric triamide, in particular N-(n-butyl) thiophosphoric triamide (nBTPT), ammonium sulphate (AS) in particulate form, and a magnesium sulphate.

(59) Aspect 21. Use of the solid, particulate urea-based blend composition as aspected in anyone of aspects 1 to 20 as a fertilizer, in particular for supporting the growth of agricultural products on a sulphur—deficient soil, a phosphor—deficient soil and/or a potassium—deficient soil.

(60) Aspect 22. Use of the solid, particulate urea-based blend composition as cited in anyone of aspects 1 to 20 as an animal feed.

(61) Aspect 23. A method for the manufacture of a solid, particulate urea-based blend composition according to any one of aspects 1 to 20, the method comprising the steps of:

(62) 1) providing a urea-based compound in particulate form;

(63) 2) providing one or more components in particulate form, selected from the group of nitrates, phosphates, sulphates and chlorides;

(64) 3) providing 0.0001 to 5 weight %, relative to the total weight of the composition, of a magnesium sulphate;

(65) 4) providing 0.0001 to 1 weight %, relative to the total weight of the composition, of a urease inhibitor of the type phosphoric triamide, preferably N-(n-butyl) thiophosphoric triamide (nBTPT);

(66) 5) optionally, providing 0.0001 to 1 weight %, relative to the total weight of the composition, of an alkaline or alkaline-forming compound, selected from the group of calcium oxide, zinc oxide, magnesium oxide, calcium carbonate, and mixtures thereof;

(67) 6) optionally, providing coating material wherein the coating material is able to increase at least the anticaking and/or moisture repellence and/or anti-dust properties of said urea-based blend composition; and

(68) 7) mixing the components provided in steps 1), 2), 3), 4), 5) and 6) in any order.

(69) Aspect 23. A kit of parts, comprising an amount of:

(70) a) a magnesium sulphate;

(71) b) a urease inhibitor of the type phosphoric triamide, preferably N-(n-butyl) thiophosphoric triamide (nBTPT);

(72) c) optionally, an alkaline or alkaline-forming compound, selected from the group of calcium oxide, zinc oxide, magnesium oxide, calcium carbonate, and mixtures thereof, and

(73) d) optionally, one or more anti-caking and/or moisture-repellent and/or anti-dust compounds.

(74) Aspect 24. Method for improving the stability of a urease inhibitor of the type phosphoric triamide, in particular N-(n-butyl) thiophosphoric triamide, (nBTPT) in a particulate urea-based blend composition comprising a urea-based compound in particulate form, one or more components in particulate form, selected from the group of nitrates, phosphates, sulphates and chlorides and said urease inhibitor by the addition to said composition of 0.0001 to 5 weight %, relative to the total weight of the composition, of a magnesium sulphate.