DUST BINDING AGENT FOR FERTILIZER

Abstract

The present invention relates to a process for reducing the formation of dust from granules based on inorganic salts or urea, in particular from fertilizer granules of this type, in which process the granules are treated with at least one fatty acid triglyceride, which is liquid at 20° C., in combination with at least one amorphous silicic acid, wherein the weight ratio of triglyceride to silicic acid is 40:1 to 3:1, and relates to the use of this triglyceride/silicic acid combination as a dust binding agent for granules based on inorganic salts or for urea granules. The invention also relates to an oil composition containing 75 to 97.6 wt % of at least one fatty acid triglyceride, which is liquid at 20° C., having certain rheological properties, and 2.4 to 25 wt % of at least one amorphous silicic acid.

Claims

1. A process for reducing the dust evolution of granules based on inorganic salts or urea, more particularly of fertilizer granules, which comprises treating the granules with a quantity of a combination comprising: c) at least one fatty acid triglyceride liquid at 20° C. or at least one fatty acid triglyceride mixture liquid at 20° C., as component A; d) at least one amorphous hydrophilic silica as component B, where said quantity reduces the dusting of the granules and where the mass ratio of component A to component B in said combination is in the range from 40:1 to 3:1.

2. The process as claimed in claim 1, where component A is selected from vegetable oils, more particularly vegetable oils having a Wijs iodine value in the range from 20 to 160, determined according to DIN 53241-1:1995-05, and mixtures of vegetable oils, with at least one of the vegetable oils contained in the mixture having this iodine number.

3. The process as claimed in claim 1 or 2, where component A has a dynamic viscosity as determined according to DIN 53019-1:2008-09, in the range from 20 to 200 mPas at 20° C. and a shear rate of 1 s.sup.−1.

4. The process as claimed in any of the preceding claims, where component A is selected from rapeseed oil, sunflower oil, corn oil, soybean oil, cottonseed oil, peanut oil, olive oil, safflower oil, hemp oil, palm olein, and mixtures thereof, and also mixtures of at least one of the aforesaid vegetable oils with palm oil or coconut oil; and where component A more particularly is selected from rapeseed oil, sunflower oil, soybean oil, palm olein, mixtures thereof, and also mixtures of at least one of the aforesaid vegetable oils with palm oil.

5. The process as claimed in any of the preceding claims, where component B has a specific surface area as determined by nitrogen adsorption according to the BET method to DIN ISO 9277:2014-01 at 77.3 K of at least 50 m.sup.2/g, more particularly in the range from 80 to 600 m.sup.2/g.

6. The process as claimed in any of the preceding claims, where component B is selected from fumed silica, precipitated silica, and mixtures thereof.

7. The process as claimed in any of the preceding claims, where the combination consists to an extent of at least 80 wt %, preferably at least 85 wt %, more particularly at least 90 wt %, especially at least 95 wt %, based on the total weight of the combination, of components A and B.

8. The process as claimed in any of the preceding claims, where the granules are selected from granules based on sulfate, chloride, phosphate or nitrate salts of potassium, magnesium, calcium or ammonium, based on mixtures thereof, based on mixed salts thereof, based on mixtures of mixed salts thereof with at least one of the above-stated salts, based on urea, or based on a mixture of at least one of the above-stated salts or mixed salts with urea; where the granules more particularly are selected from MOP, SOP, Korn-Kali (granular potash), Patentkali (patent potash), kieserite, ammonium sulfate, MAP, DAP, CAS, TSP, NPK, polyhalite, and urea granules, and also granules containing at least two of these components.

9. The process as claimed in any of the preceding claims, where components A and B are used separately or in a mixture for treating the granules, the granules in the case of separate use being treated concurrently with component A and component B.

10. The process as claimed in claim 9, where the combination of components A and B is used in the form of an oil composition which contains a) 75 to 97.6 wt %, preferably 83.3 to 97.6 wt %, more preferably 87.5 to 96.8 wt %, more particularly 88.9 to 96.4 wt %, especially 88.9 to 96.2 wt %, based on the total weight of the oil composition, of component A; and b) 2.4 to 25 wt %, preferably 2.4 to 16.7 wt %, more preferably 3.2 to 12.5 wt %, more particularly 3.6 to 11.1 wt %, especially 3.8 to 11.1 wt %, based on the total weight of the oil composition, of component B.

11. The process as claimed in claim 10, where the oil composition is shear-thinning.

12. The process as claimed in claim 11, where the oil composition at 20° C. and a shear rate of 1 s.sup.−1 has a dynamic viscosity of at least 500 mPas and at 20° C. and a shear rate of 300 s.sup.−1 has a dynamic viscosity which is at least 200 mPas below the dynamic viscosity of the oil composition at 20° C. and a shear rate of 1 s.sup.−1) the viscosity values being determined according to DIN 53019-1:2008-09.

13. The process as claimed in any of claims 1 to 8, where components A and B are used separately and successively for treating the granules, the time interval between the treatment with component A and the treatment with component B being at most 2 minutes, preferably at most 1 minute, more particularly at most 30 seconds.

14. The process as claimed in any of the preceding claims, where the combination contains component A and component B in a mass ratio A:B in the range from 40:1 to 5:1, preferably in the range from 30:1 to 7:1, more particularly in the range from 27:1 to 8:1, and especially in the range from 25:1 to 9:1.

15. The process as claimed in any of the preceding claims, where the combination is used in an amount of 1 to 10 kg per metric ton of granules, more particularly of 2 to 7 kg per metric ton of granules.

16. The use of a combination comprising c) at least one fatty acid triglyceride liquid at 20° C. or at least one fatty acid triglyceride mixture liquid at 20° C., as component A; d) at least one amorphous silica as component B, where the mass ratio of component A to component B in said combination is in the range from 40:1 to 3:1, as an antidusting agent for granules based on inorganic salts or for urea granules, more particularly for fertilizer granules.

17. The use as claimed in claim 16, where the combination has at least one of the features of claims 1 to 14.

18. An oil composition containing c) 75 to 97.6 wt %, based on the total weight of the oil composition, of a fatty acid triglyceride liquid at 20° C. or of at least one fatty acid triglyceride mixture liquid at 20° C., as component A, where component A has a dynamic viscosity as determined according to DIN 53019-1:2008-09 in the range from 20 to 200 mPas at 20° C. and a shear rate of 1 s.sup.−1; d) 2.4 to 25 wt %, based on the total weight of the oil composition, of at least one amorphous hydrophilic silica as component B, where component B is present in the oil composition in an amount of at least 6.5 wt %, based on the total weight of the oil composition, when component B is fumed silica.

19. The oil composition as claimed in claim 18, where component A has at least one of the features of claim 2 or 4.

20. The oil composition as claimed in either of claims 18 and 19, where component B has at least one of the features of claim 5 or 6.

21. The oil composition as claimed in any of claims 18 to 20, containing c) 83.3 to 97.6 wt %, preferably 87.5 to 96.8 wt %, more particularly 88.9 to 96.4 wt %, especially 88.9 to 96.2 wt %, based on the total weight of the oil composition, of component A; and d) 2.4 to 16.7 wt %, preferably 3.2 to 12.5 wt %, more particularly 3.6 to 11.1 wt %, especially 3.8 to 11.1 wt %, based on the total weight of the oil composition, of component B.

22. The oil composition as claimed in any of claims 18 to 21, containing component A and component B in a mass ratio A:B in the range from 40:1 to 3:1, preferably in the range from 40:1 to 5:1, more preferably in the range from 30:1 to 7:1, more particularly in the range from 27:1 to 8:1, and especially in the range from 25:1 to 9:1.

23. The oil composition as claimed in any of claims 18 to 22, where the oil composition is shear-thinning.

24. Granules obtainable by the process as claimed in any of claims 1 to 15.

Description

EXAMPLES

[0138] Oils used were as follows:

Rapeseed oil

Sunflower oil

Soybean oil

[0139] RBD palm oil from Olenex (RBD=refined bleached deodorized)
RBD palm olein 64 SG from Olenex (refined palm olein; RBD=refined bleached deodorized)
Silica products used were as follows:
Sipernat® 22 S from Evonik
Sipernat® 50 from Evonik
Sipernat® D 17 from Evonik
Aerosil® 200 F from Evonik

[0140] Additionally tested for comparison were quartz sand as a different source of silicon, and also precipitated calcium carbonate.

[0141] As fertilizer granules the following products were used:

SOP:

[0142] Press granules

Granulometry 2-4 mm (80-90%)

[0143] D.sub.50 typically 2.8 mm
Chemical composition:

TABLE-US-00001 K.sub.2SO.sub.4 typically 93.5% Other sulfates (MgSO.sub.4, CaSO.sub.4) typically 3% Chlorides (KCl, NaCl) typically 1.5% Others (primarily water of crystallization) typically 2%

MOP:

[0144] Press granules

Granulometry 2-4 mm (85-95%)

[0145] D.sub.50 typically 2.8 mm
Chemical composition:

TABLE-US-00002 KCI typically 95.4% Secondary constituents (NaCl, MgCl.sub.2, MgSO.sub.4, K.sub.2SO.sub.4, typically 4.4% CaSO.sub.4) Adhering moisture typically 0.2%

Korn-Kali (Granular Potash):

[0146] Press granules
Granulometry 2-5 mm (about 94%)
D.sub.50 typically 3.4 mm
Chemical composition:

TABLE-US-00003 KCl typically 63.5% NaCl typically 9.5% MgSO.sub.4 typically 17.0% MgCl.sub.2, K.sub.2SO.sub.4, CaSO.sub.4 typically 5.5% Others (primarily water of crystallization) typically 4.5%

Patentkali (Patent Potash):

[0147] Roll granules
Granulometry 2-5 mm (about 92%)
D.sub.50 typically 3.1 mm
Chemical composition:

TABLE-US-00004 K.sub.2SO.sub.4 typically 50.5% MgSO.sub.4 typically 30.5% Other sulfates (CaSO.sub.4 etc.) typically 1.5% Chlorides (KCl, NaCl) typically 5.5% Others (primarily water of crystallization) typically 12%

NPK:

[0148] Granulometry 2-4 mm (about 95%)
D.sub.50 typically 3.2 mm
Chemical composition:

TABLE-US-00005 K.sub.2O typically 15% N (ammonium) typically 15% P.sub.2O.sub.5 (phosphate) typically 13% S (sulfate) typically 11% Chlorides typically 12%

1) Rheological Study of the Starting Materials

[0149] The dynamic viscosity of the vegetable oils and of the mixtures with the amorphous silicas was determined according to DIN 53019-1:2008-09 at 20° C. (unless otherwise noted). For this purpose an MCR 502 from Anton Paar was used with a plate-to-plate distance of 1 mm (plate diameter 6 mm).

[0150] The dynamic viscosity of the oils is shown in table 1.

TABLE-US-00006 TABLE 1 Dynamic viscosity [mPas] Shear rate 1 s.sup.−1 Shear rate 300 s.sup.−1 RBD palm oil FP n.d. 257 RBD palm olein 87 88 Rapeseed oil 72 73 Sunflower oil 69 66 Soybean oil 66 65

[0151] Various mixtures of rapeseed oil and amorphous silicas or quartz sand as other source of silicon and/or precipitated calcium carbonate were prepared in different weight proportions and their viscosity was measured.

[0152] Table 2 shows the viscosity behavior of mixtures of rapeseed oil with different amorphous silicas or quartz sand and/or precipitated calcium carbonate in a weight ratio of 11:1.

TABLE-US-00007 TABLE 2 Dynamic viscosity [mPas] Shear rate 1 s.sup.−1 Shear rate 300 s.sup.−1 Rapeseed oil + CaCO.sub.3 (precipitated)  346 104 11:1 (comparative) Rapeseed oil + quartz sand 11:1  88 81 (comparative) Rapeseed oil + Sipernat 50 11:1 6454 248 Rapeseed oil + Sipernat 22 S 11:1 23 768   307 Rapeseed oil + Aerosil 200 F 11:1 9325 393 Rapeseed oil + Sipernat D 17 11:1  448 123

[0153] As is seen, the mixtures according to the invention are thickened, but have a shear-thinning behavior, as can be perceived from the significantly lower viscosity at a shear rate of 300 s.sup.−1 (by comparison with the viscosity at a shear rate of 1 s.sup.−1).

[0154] Table 3 shows the viscosity behavior of mixtures of various oils with Sipernat® 22 S in a weight ratio of 11:1.

TABLE-US-00008 TABLE 3 Dynamic viscosity [mPas] Shear rate 1 s.sup.−1 Shear rate 300 s.sup.−1 Rapeseed oil + Sipernat 22 S 11:1 23 768 307 Sunflower oil + Sipernat 22 S 11:1 22 265 283 Soybean oil + Sipernat 22 S 11:1 23 159 297 RBD palm olein + Sipernat 22 S 11:1 13 999 221

[0155] Table 4 shows the viscosity behavior of mixtures of various oils with Aerosil® 200 F in a weight ratio of 22:1.

TABLE-US-00009 TABLE 4 Dynamic viscosity [mPas] Shear rate 1 s.sup.−1 Shear rate 300 s.sup.−1 Rapeseed oil + Aerosil 200 F 22:1 1666 166 Sunflower oil + Aerosil 200 F 22:1 1417 151 Soybean oil + Aerosil 200 F 22:1 31 449   275 RBD palm olein + Aerosil 200 F 22:1 15 029   483

[0156] Table 5 shows the viscosity behavior of mixtures of rapeseed oil with Sipernat® 22 S in various weight ratios.

TABLE-US-00010 TABLE 5 Dynamic viscosity [mPas] Shear rate 1 s.sup.−1 Shear rate 300 s.sup.−1 Rapeseed oil + Sipernat 22 S 110:1    89 80 (comparative) Rapeseed oil + Sipernat 22 S 37:1    300 98 Rapeseed oil + Sipernat 22 S 22:1   1990 133 Rapeseed oil + Sipernat 22 S 11:1  23 768 307 Rapeseed oil + Sipernat 22 S 11:2 163 440 637 Rapeseed oil + Sipernat 22 S 11:3 304 500 n.d.

[0157] As can be perceived, for a weight ratio of 110:1 the thickening effect of Sipernat® 22 S is negligible.

[0158] Table 6 shows the viscosity behavior of mixtures of rapeseed oil with Aerosil® 200 F in various weight ratios.

TABLE-US-00011 TABLE 6 Dynamic viscosity [mPas] Shear rate 1 s.sup.−1 Shear rate 300 s.sup.−1 Rapeseed oil + Aerosil 200 F 110:1 137 85 (comparative) Rapeseed oil + Aerosil 200 F 37:1 559 118 Rapeseed oil + Aerosil 200 F 22:1 1666 166

[0159] As can be perceived, for a weight ratio of 110:1 the thickening effect of Aerosil® 200 F is not very pronounced.

[0160] Table 7 shows the temperature dependence of the viscosity of mixtures of rapeseed oil with Sipernat® 22 S in a weight ratio of 11:1.

TABLE-US-00012 TABLE 7 Dynamic viscosity [mPas] Temp. Shear rate 1 s.sup.−1 Shear rate 300 s.sup.−1 Rapeseed oil + Sipernat 22 20° C. 23 327 303 S 11:1 40° C. 19 408 201 60° C. 12 088 143

[0161] Table 8 shows the temperature dependence of the viscosity of mixtures of rapeseed oil with Aerosil® 200 F in a weight ratio of 11:1.

TABLE-US-00013 TABLE 8 Dynamic viscosity [mPas] Temp. Shear rate 1 s.sup.−1 Shear rate 300 s.sup.−1 Rapeseed oil + Aerosil 200 20° C. 9325 390 F 11:1 40° C. 6359 211 60° C. 4014 127

2) Treatment of Granules

[0162] Unless otherwise described, the granules were first charged with oil and homogenized for 15 seconds. Subsequently component B was added and homogenization took place for a further 45 seconds. The temperature which the granules each had during the treatment (between 25 and 60° C.) is reported below.

3) Study of the Dust Behavior

[0163] After one and after three weeks of storage, 100 g samples of granules were first stressed (about 40 rpm) by shaking using an overhead shaker (comparable with the RA 20 product from Gerhard) for 5 minutes in a flask (30 cm height; diameter 8 cm).

[0164] The dust count was then determined using a DustView II from PALAS. Here, after a 50 cm drop, a measurement is made of the attenuation of a laser beam after 0.5 and 30 s. This is done by applying a sample to a sample hopper. The opening of a flap allows the sample to fall into a dust chamber, where dust is swirled and attenuates the laser beam. The attenuation is expressed as a dust value, with a value of 0 denoting that the laser beam is not shadowed (i.e., only marginal dust fractions or none) and a value of 100 representing complete shadowing of the laser beam as a result of swirling dust. The dust count corresponds to the sum total of the dust value after 0.5 s and the dust value after 30 s following impact. The aim is for a dust count of less than 0.5, better still less than 0.3 or even less than 0.2.

[0165] The dust counts reported below correspond to the mean value from 4 measurements on 4 samples.

3.1) SOP Granules (Broken Granules)

[0166] The temperature of the base granules (=untreated SOP granules) on granule treatment (see 2)) was 40° C.

[0167] Table 9 shows the dust behavior of granules obtained by treating broken SOP granules with rapeseed oil and various silicas in a weight ratio of 11:1, after 1-week and 3-week storage. The quantities of oil and silica used per metric ton of base granules are reported. For comparison, studies were carried out on the base granules in untreated form, in a form treated only with rapeseed oil, or in a form treated with a mixture of rapeseed oil and quartz sand or calcium carbonate.

TABLE-US-00014 TABLE 9 SOP Dust count Dust count Treatment 1-week value 3-week value untreated 22.2 26.8 +5.5 kg/t Rapeseed oil 1.0 1.1 +5.5 kg/t Rapeseed oil 0.1 0.1 +0.5 kg/t Sipernat 22 S +5.5 kg/t Rapeseed oil 0.1 0.1 +0.5 kg/t Aerosil 200 F +5.5 kg/t Rapeseed oil 0.0 0.0 +0.5 kg/t Sipernat 50 +5.5 kg/t Rapeseed oil 0.2 0.2 +0.5 kg/t Sipernat D 17 +5.5 kg/t Rapeseed oil 0.9 1.1 +0.5 kg/t Quartz sand +5.5 kg/t Rapeseed oil 0.7 0.8 +0.5 kg/t Precipitated CaCO.sub.3

[0168] As can be seen, the treatment in the invention leads to the most effective suppression of dust evolution. The use solely of amorphous silicas, such as Sipernat 22 S, Sipernat 50, Sipernat D 17 or Aerosil 200 F, for example, does not lead to a reduction in the dust count.

[0169] Table 10 shows the dust behavior of granules obtained by treating broken SOP granules with various oils and Sipernat® 22 S or Aerosil® 200 F in a weight ratio of 11:1, after 1-week and 3-week storage. The quantities of oil and silica used per metric ton of base granules are reported. For comparison, studies were carried out on the base granules in untreated form and in a form treated only with the respective oil.

TABLE-US-00015 TABLE 10 SOP Dust count Dust count Treatment 1-week value 3-week value untreated 22.2 26.8 +5.5 kg/t Rapeseed oil 1.0 1.1 +5.5 kg/t Rapeseed oil 0.1 0.1 +0.5 kg/t Sipernat 22 S +5.5 kg/t Rapeseed oil 0.1 0.1 +0.5 kg/t Aerosil 200 F +5.5 kg/t Sunflower oil 2.2 1.5 +5.5 kg/t Sunflower oil 0.1 0.0 +0.5 kg/t Sipernat 22 S +5.5 kg/t Sunflower oil 0.1 0.1 +0.5 kg/t Aerosil 200 F +5.5 kg/t Soybean oil 1.2 1.0 +5.5 kg/t Soybean oil 0.1 0.1 +0.5 kg/t Sipernat 22 S +5.5 kg/t Soybean oil 0.1 0.1 +0.5 kg/t Aerosil 200 F +5.5 kg/t RBD Palm Olein 0.9 1.3 +5.5 kg/t RBD Palm Olein 0.1 0.2 +0.5 kg/t Sipernat 22 S +5.5 kg/t RBD Palm Olein 0.1 0.2 +0.5 kg/t Aerosil 200 F

[0170] All combinations according to the invention exhibit outstandingly low dust count values. The use solely of amorphous silicas, such as Sipernat 22 S or Aerosil 200 F, for example, does not lead to a reduction in the dust count.

[0171] Table 11 shows the dust behavior of granules obtained by treatment of broken SOP granules by various methods (mixing methods) with rapeseed oil and Sipernat® 22 S in a weight ratio of 11:1, after 1-week and 3-week storage. The quantities of oil and silica used per metric ton of base granules are reported. For comparison, studies were carried out on the base granules in untreated form and in a form treated only with rapeseed oil.

TABLE-US-00016 TABLE 11 SOP Dust count Dust count Treatment 1-week value 3-week value untreated 22.2 26.8 +5.5 kg/t Rapeseed oil 1.0 1.1 +5.5 kg/t Rapeseed oil 0.1 0.1 +0.5 kg/t Sipernat 22 S +5.5 kg/t Rapeseed oil 0.1 0.1 +0.5 kg/t Sipernat 22 S mixed manually via glass rod for 1 min prior to addition +5.5 kg/t Rapeseed oil 0.1 0.1 +0.5 kg/t Sipernat 22 S mixed via paddle stirrer for 1 min prior to addition (300 rpm) +5.5 kg/t Rapeseed oil 0.1 0.1 +0.5 kg/t Sipernat 22 S mixed via Ultra-Turrax for 1 min prior to addition (20 000 rpm)

[0172] As can be seen, the different mixing methods have no consequence for the dust-binding effect.

[0173] Table 12 shows the dust behavior of granules obtained by treating broken SOP granules with rapeseed oil/palm oil mixtures and with various Sipernat® silicas in a weight ratio of 11:1, after 1-week, 3-week and 6-week storage. The quantities of oil and silica used per metric ton of base granules are reported. For comparison the base granules were studied in untreated form.

TABLE-US-00017 TABLE 12 SOP Dust count Dust count Dust count Treatment 1-week value 3-week value 6-week value untreated 22.2 26.8 20.0 +5.5 kg/t Rapeseed oil 0.1 0.1 0.0 +0.5 kg/t Sipernat 22 S +5.5 kg/t Rapeseed oil/palm 0.1 0.0 0.0 oil 50:50 +0.5 kg/t Sipernat 22 S +5.5 kg/t Rapeseed oil/palm 0.1 0.1 0.0 oil 50:50 +0.5 kg/t Sipernat 50 +5.5 kg/t Rapeseed oil/palm 0.3 0.2 0.3 oil 50:50 +0.5 kg/t Sipernat D 17

[0174] Table 13 shows the dust behavior of granules obtained by treating broken SOP granules with rapeseed oil and with Sipernat® 22 S in various weight ratios, after 1-week and 3-week storage. The quantities of oil and silica used per metric ton of base granules are reported. For comparison, studies were carried out on the base granules in untreated form and in a form treated only with rapeseed oil.

TABLE-US-00018 TABLE 13 SOP Dust count Dust count Treatment 1-week value 3-week value untreated 22.2 26.8 +5.5 kg/t Rapeseed oil 1.0 1.1 +5.5 kg/t Rapeseed oil 1.1 0.9 +0.05 kg/t Sipernat 22 S +5.5 kg/t Rapeseed oil 0.4 0.5 +0.15 kg/t Sipernat 22 S +5.5 kg/t Rapeseed oil 0.4 0.2 +0.25 kg/t Sipernat 22 S +5.5 kg/t Rapeseed oil 0.1 0.1 +0.5 kg/t Sipernat 22 S +5.5 kg/t Rapeseed oil 0.0.sup.# 0.0.sup.# +1.0 kg/t Sipernat 22 S +5.5 kg/t Rapeseed oil 0.0.sup.# 0.0.sup.# +1.5 kg/t Sipernat 22 S +5.5 kg/t Rapeseed oil 0.0.sup.## 0.0.sup.## +2.5 kg/t Sipernat 22 S .sup.#slight sticking observed on the vessel wall during shaking .sup.##granules stick severely and can no longer be handled

[0175] Table 14 shows the dust behavior of granules obtained by treating broken potassium sulfate (SOP) granules with rapeseed oil and with Aerosil® 200 F in various weight ratios, after 1-week and 3-week storage. The quantities of oil and silica used per metric ton of base granules are reported. For comparison, studies were carried out on the base granules in untreated form and in a form treated only with rapeseed oil.

TABLE-US-00019 TABLE 14 SOP Dust count Dust count Treatment 1-week value 3-week value untreated 22.2 26.8 +5.5 kg/t Rapeseed oil 1.0 1.1 +5.5 kg/t Rapeseed oil 0.6 0.8 +0.05 kg/t Aerosil 200 F +5.5 kg/t Rapeseed oil 0.4 0.3 +0.15 kg/t Aerosil 200 F +5.5 kg/t Rapeseed oil 0.2 0.2 +0.25 kg/t Aerosil 200 F +5.5 kg/t Rapeseed oil 0.1 0.1 +0.5 kg/t Aerosil 200 F +5.5 kg/t Rapeseed oil 0.0.sup.# 0.0.sup.# +1.0 kg/t Aerosil 200 F +5.5 kg/t Rapeseed oil 0.0.sup.# 0.0.sup.# +1.5 kg/t Aerosil 200 F +5.5 kg/t Rapeseed oil 0.0.sup.## 0.0.sup.## +2.5 kg/t Aerosil 200 F .sup.#slight sticking observed on the vessel wall during shaking .sup.##granules stick severely and can no longer be handled

[0176] Studies with conventional antidusting agents based on thickened mineral oils show that the combination according to the invention leads to a comparable dust-binding effect in fertilizer granules.

3.2) MOP Granules (Broken Granules)

[0177] The temperature of the base granules (=untreated MOP granules) on granule treatment was 60° C.

[0178] Table 15 shows the dust behavior of granules obtained by treating broken MOP granules with rapeseed oil and with Sipernat® 22 S or Aerosil® 200 F in a weight ratio of about 11:1, after 1-week and 3-week storage (15 min instead of 5 min of stressing for determining the value after 3-week storage). The quantities of oil and silica used per metric ton of base granules are reported. For comparison, studies were carried out on the base granules in untreated form and in a form treated only with rapeseed oil.

TABLE-US-00020 TABLE 15 MOP Dust count Dust count Treatment 1-week value 3-week value untreated 2.8 10.4* +2.5 kg/t Rapeseed oil 0.0 0.2* +2.5 kg/t Rapeseed oil 0.0 0.0* +0.23 kg/t Sipernat 22 S +2.5 kg/t Rapeseed oil 0.0 0.0* +0.23 kg/t Aerosil 200 F *stressed for 15 min rather than 5 min.

3.3) Granules Based on Korn-Kali (Granular Potash) (Broken Granules)

[0179] The temperature of the base granules (=untreated Korn-Kali granules) on granule treatment (see 2)) was 50° C.

[0180] Table 16 shows the dust behavior of granules obtained by treating broken Korn-Kali granules with rapeseed oil and with Sipernat® 22 S or Aerosil® 200 F in a weight ratio of about 11:1, after 1-week and 3-week storage. The quantities of oil and silica used per metric ton of base granules are reported. For comparison, studies were carried out on the base granules in untreated form and in a form treated only with rapeseed oil.

TABLE-US-00021 TABLE 16 Korn-Kali Dust count Dust count Treatment 1-week value 3-week value untreated 16.3 12.1 +4.5 kg/t Rapeseed oil 3.6 3.8 +4.5 kg/t Rapeseed oil 0.1 0.1 +0.41 kg/t Sipernat 22 S +4.5 kg/t Rapeseed oil 0.0 0.0 +0.41 kg/t Aerosil 200 F

3.4) Patentkali (Patent Potash) Granules (Roll Granules)

[0181] The temperature of the base granules (=untreated Patentkali granules) on granule treatment was 25° C.

[0182] Table 17 shows the dust behavior of granules obtained by treating Patentkali roll granules with rapeseed oil and with Sipernat® 22 S in a weight ratio of 9:1, after 1-week and 3-week storage. The quantities of oil and silica used per metric ton of base granules are reported. For comparison, studies were carried out on the base granules in untreated form.

TABLE-US-00022 TABLE 17 Patentkali granules Dust count Dust count Treatment 1-week value 3-week value untreated 19.3 20.1 +2.7 kg/t Rapeseed oil 0.2 0.2 +0.3 kg/t Sipernat 22 S

3.5) NPK Granules

[0183] The temperature of the base granules (=untreated NPK granules) on granule treatment was 20° C.

[0184] Table 18 shows the dust behavior of granules obtained by treating NPK granules with rapeseed oil and with Sipernat® 22 S or Aerosil® 200 F in a weight ratio of 10:1, after 1-week and 3-week storage. The quantities of oil and silica used per metric ton of base granules are reported. For comparison, studies were carried out on the base granules in untreated form and in a form treated only with rapeseed oil.

TABLE-US-00023 TABLE 18 NPK granules Dust count Dust count Treatment 1-week value 3-week value untreated 16.4 19.7 +3.0 kg/t Rapeseed oil 0.6 0.8 +3.0 kg/t Rapeseed oil 0.1 0.1 +0.3 kg/t Sipernat 22 S +3.0 kg/t Rapeseed oil 0.1 0.1 +0.3 kg/t Aerosil 200 F

3.6) SOP Granules (Broken Granules)—Various Treatment Methods

[0185] The temperature of the base granules (=untreated SOP granules) on granule treatment was 20° C.

[0186] Table 19 shows the dust behavior of granules obtained by various treatment methods (joint or separate addition of silica and oil) for broken SOP granules with RBD palm olein and Sipernat® 22 S in a weight ratio of 11:1, after 1-week and 3-week storage. The quantities of oil and silica used per metric ton of base granules are reported.

TABLE-US-00024 TABLE 19 SOP Dust count Dust count Treatment 1-week value 3-week value +5.5 kg/t RBD Palm olein 0.1 0.1 +0.5 kg/t Sipernat 22 S separate but concurrent addition +5.5 kg/t RBD Palm olein 0.2 0.1 +0.5 kg/t Sipernat 22 S first addition of RBD Palm olein; addition of Sipernat 22 S after 15 s +5.5 kg/t RBD Palm olein 0.1 0.1 +0.5 kg/t Sipernat 22 S first addition of Sipernat 22 S; addition of RBD Palm olein after 15 s