EP4028377A1

EP4028377A1 - Dust binding agent for fertilizer

Info

Publication number: EP4028377A1
Application number: EP20789821.4A
Authority: EP
Inventors: Sebastian KOPF; Christof Dehler; Sören Seebold; Stefan Dressel; Guido BAUCKE
Original assignee: K S AG; K+S AG
Current assignee: K S AG; K+S AG
Priority date: 2019-09-10
Filing date: 2020-09-07
Publication date: 2022-07-20
Also published as: CN114650976A; BR112022004328A2; US20220332659A1; WO2021047705A1; DE102019006367A1

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.

Description

Dust binders for fertilizers

The present invention relates to a process for reducing the formation of dust from granules based on inorganic salts or urea, in particular from such fertilizer granules, in which the granules are treated with at least one fatty acid triglyceride which is liquid at 20 ° C. in combination with at least one amorphous, hydrophilic silica, the weight ratio of triglyceride to silica being 40: 1 to 3: 1. The invention further relates to an oil composition containing 75 to 97.6% by weight of at least one fatty acid triglyceride which is liquid at 20 ° C. and has certain rheological properties and 2.4 to 25% by weight of at least one amorphous, hydrophilic silica. The invention also relates to the use of a combination of at least one fatty acid triglyceride liquid at 20 ° C. and at least one amorphous silica, the weight ratio of triglyceride to silica being 40: 1 to 3: 1, as a dust binder for granules based on inorganic salts or for urea granules .

Mineral fertilizers are often used in the form of granules, as they have advantageous handling properties in this form. Compared to the corresponding finely divided, powdery mineral fertilizers, granulates tend to form much less dust, are more stable in storage, more hygroscopic and can be spread and dosed more easily and more evenly by sprinkling. In addition, granules applied to open spaces are also less susceptible to wind drifts.

Since such granules are often not particularly stable with respect to mechanical stress, for example during transport and when filling into silos, transport containers and the like, not inconsiderable abrasion and thus dust development can occur. It is obvious that the development of dust should be suppressed as far as possible for reasons of occupational safety. Dust development also means material loss of product, sometimes considerable loss of quality and damage to the environment; in addition, the dust is often hygroscopic and can lead to caking of the granulate particles. Accordingly, good product quality is characterized, among other things, by low dust generation.

In order to reduce the generation of dust from fertilizer granules, one typically uses dust binders, which are also referred to as dust protection agents, dust reducing agents, dust control agents or anti-dust agents. This is what it is

CONFIRMATION COPY are typically liquid products which cause the dust particles to adhere to the surface of the granules or lead to an agglomeration of the dust particles. Often these are mineral oils - see Fertilizer Manual, UN Industrial Development Organization, Int'l Fertilizer Development Center (Eds.) 3rd ed. Kluwer Academic Publishers, page 492 ff and references cited therein.

DD 101657 describes the use of a solution of 5 to 40% by weight of bitumen in mineral oil to reduce the formation of dust from urea granules.

EP 255665 describes the use of a mixture of 2 to 10% by weight of polyethylene wax, 20 to 35% by weight of microcrystalline wax and 70 to 80% by weight of mineral oil to reduce the hygroscopicity and dust formation of nitrate-containing fertilizer granules.

WO 2016/168801 describes the use of stearates as dust binders, which are formulated with a mineral oil.

Dust binders based on mineral oils have a good dust binding effect. In view of the environmental compatibility of fertilizers and other agricultural products, however, one would like to reduce the use of mineral oils in these products.

WO 02/090295 describes compositions which contain a wax, an oil, for example a vegetable or animal oil, a natural resin or a resinous distillation residue of a vegetable or animal oil and a surface-active substance, as a dust-reducing additive for nitrogen fertilizers . However, these formulations are complex and the necessary starting materials are not readily available.

DE 102011003268 describes dust binders for dry mixes of building material formulations. Polysiloxanes, fatty acid derivatives, natural oils or hydrocarbons applied to inorganic carriers are used as dust binders. Preferred among these are fatty acids and fatty acid derivatives, more preferably hydrocarbons and particularly preferably polysiloxanes. Silicas, among others, are mentioned as suitable carriers. The supported dust reducing agents are generally in solid form and can at most still be pasty. This supported form of formulation should make it possible to efficiently incorporate the dust reducing agents into dry building material formulations without additional work steps or equipment would be necessary to introduce (liquid) dust reducing agents into the dry building material formulations.

However, this procedure is not practical for less complex products or for formulations that are basically finished, such as fertilizer formulations. In these cases it is usually desirable to be able to treat the actually finished products or formulations in one simple step to prevent the development of dust.

However, omitting the inorganic carrier material of the dust reduction formulation of DE 102011003268 does not lead to the desired goal. This is because the present inventors have found that the simple treatment of fertilizer formulations with vegetable oils has no or at least no satisfactory dust-binding effect.

EP 141410 describes a process for increasing the viscosity of oils, in which the oil is mixed with a combination of 0.1 to 10% by weight of a high-melting fatty acid glyceride of saturated Ci4-C24 fatty acids and 0.2 to 10% by weight. % of a highly disperse silica, in particular a pyrogenic silica, formulated. These formulations are proposed as cosmetic and pharmaceutical oils, lubricants, edible oils or as release agents for baked goods.

CN 107793216 describes an anti-caking agent for fertilizers which contains 10-20% by weight of hydrogenated tallow amine, 10-20% by weight of Ce-C2o fatty acids or corresponding fats, 50-75% by weight of an oil component and 5-10% by weight. - contains modified nano-silica. The oils can include vegetable oils. The modified nano-silica is a hydrophobized silica modified with the silane coupling reagent KH550. An anti-dust effect of this mixture is not described. The type and form of the fertilizer is also not mentioned.

The object of the present invention was therefore to provide a dust-binding agent which effectively prevents or at least reduces the formation of dust from inorganic granules, in particular from (inorganic) fertilizer granules, and which is environmentally friendly, ie non-toxic and easily degradable. The agent should also be easy to apply to the granules; In particular, it should be able to be applied easily and without great expenditure on equipment by spraying or other methods of applying liquid components. Furthermore, the agent should also be able to be applied to freshly produced granules. Productive Fresh granules are usually hot. If it has to be cooled down before further processing, this means, among other things, a loss of time, which of course causes costs. Pure vegetable oils are not suitable for such a direct treatment of freshly produced granules, as they are presumably immediately absorbed by them.

It has surprisingly been found that a combination of fatty acid triglycerides and amorphous silica in a certain quantitative ratio achieves the object of the invention.

The invention therefore relates to a method for reducing the dust generation of granules based on inorganic salts or urea granules, in particular (inorganic) fertilizer granules, comprising the treatment of the granules with an amount of a combination comprising: a) at least one Fatty acid triglyceride which is liquid at 20 ° C. or at least a mixture of fatty acid triglycerides which is liquid at 20 ° C. as component A; b) at least one amorphous, hydrophilic silica as component B, where in the combination the mass ratio of component A to component B is in the range from 40: 1 to 3: 1, often in the range from 40: 1 to 5: 1, preferably in the range from 30: 1 to 7: 1, in particular in the range from 27: 1 to 8: 1 and especially in the range from 25: 1 to 9: 1.

The invention also relates to the use of a combination comprising a) at least one fatty acid triglyceride liquid at 20.degree. C. or at least one mixture of fatty acid triglycerides liquid at 20.degree. C. as component A; b) at least one amorphous silica as component B, where in the combination the mass ratio of component A to component B is in the range from 40: 1 to 3: 1, often in the range from 40: 1 to 5: 1, preferably in the range from 30 : 1 to 7: 1, in particular in the range from 27: 1 to 8: 1 and especially in the range from 25: 1 to 9: 1, as a dust binder for granules based on inorganic salts or for urea granules, especially for (inorganic) fertilizer granules .

The invention also relates to an oil composition containing a) 75 to 97.6% by weight, based on the total weight of the oil composition, of a fatty acid triglyceride that is liquid at 20 ° C. or at least one mixture of fatty acid triglycerides that is liquid at 20 ° C., as component A, with component A at 20 ° C. and a shear rate of 1 s ^{1 has} a dynamic viscosity, determined according to DIN 53019-1: 2008-09, in the range from 20 to 200 mPas; and b) 2.4 to 25% by weight, based on the total weight of the oil composition, of at least one amorphous, hydrophilic silica as component B.

Finally, the invention also relates to a granulate which can be obtained by the process according to the invention.

Definitions

The term “granulate” denotes powder particle agglomerates which can be obtained by combining powder particles to form larger particle units, so-called granulate particles or granules. The particle size (grain size) of the granulate particles is generally in the range from 1 to 10 mm, preferably from 2 to 5 mm. The grain size is determined by sieving according to DIN EN 1235 with a square mesh according to DIN ISO 3310-1.

Granules can have various shapes and morphologies due to the manufacturing process and can be manufactured using various processes. A large number of agglomeration processes and an even larger number of agglomeration devices are used here. In the fertilizer industry, for example, processes such as prilling, build-up agglomeration or press agglomeration are used.

In prilling (spray crystallization), for example, melts are broken up into small droplets in a prilling tower and cooled in free fall by a cold countercurrent of fresh air. The resulting solidified granules are characterized by a very homogeneous grain size and shape.

The compression and build-up agglomeration is characterized by the fact that disperse solid primary particles are agglomerated with an increase in the grain size. Both types of process are often carried out in the presence of granulating aids. These are liquid or solid substances whose adhesive forces cause the primary particles to stick together. The use of such granulation aids is especially necessary if the granulation of the primary particles without these auxiliaries does not lead to a sufficiently stable granulate. Known granulation auxiliaries are, for example, water, gelatine, starch, lignosulphonates, lime and molasses.

Press granulation is usually carried out with small proportions or without the addition of liquids. The primary particles are compacted in the form of a powder by means of a force applied to the primary particles, whereby the grain or particle diameter is increased. In the case of press agglomeration, for example, the powder is compacted by means of roller presses. The resulting compact is called a scab. In order to obtain a defined grain size, the compacting is followed by crushing the flakes by means of a grinder and, if necessary, then classifying the crushed flakes, the desired granulate size being obtained as good grain. A device for roller compacting usually comprises the assemblies of a conveyor system which conveys the powder into the compacting zone between the rollers, a compacting unit in which the powder is pressed between at least two mutually rotating rollers with a certain force to form a scab, and a grinding unit, which the scab is crushed to the desired size, and optionally a classifying unit.

The process of build-up agglomeration also includes, for example, roll granulation, in which the finely divided starting material, i.e. the primary particles, are moved intensively with the addition of an aqueous liquid, so that there are numerous collisions between the primary particles, which are then caused by the capillary forces conveyed by the liquid store together in the form of germs. These nuclei can then aggregate with one another or with other primary particles. The constant movement leads to a continuous build-up of particle layers and to the compaction of the particles, so that in the end moist granules (green granules) are obtained, which are then dried and classified into the finished granules.

In addition to the good grain, the classification also produces granulates with particle sizes outside the target fraction. Granules that are too large, also known as oversized particles, are usually comminuted after the classification and fed back to the respective granulation process together with the granules that are too fine (undersized particles) from the classification. Granules of the target fraction of the respective agglomeration process are optionally fed to an after-treatment to improve their properties. The products obtained in the press agglomeration have a rather angular shape; at least in comparison to rolled granules.

Fertilizers are substances that are used in agriculture to supplement the nutrient supply for the cultivated crops. In the context of the present invention, however, the term only refers to inorganic fertilizers (mineral fertilizers), i.e. inorganic salts which are suitable as fertilizers, and urea. Urea, which can be seen as the boundary link between organic and inorganic chemistry, is regarded as an inorganic compound in the context of the present invention and is therefore counted among the inorganic fertilizers.

The term “combination” of components A and B denotes both a physical mixture of the two components A and B as well as any form of application in which the two components are used separately, but in a temporal context. In the process according to the invention or in the use according to the invention, the treatment of the granules can therefore take place on the one hand with a physical mixture of components A and B, but on the other hand also with component A and component B separately, the treatment with the individual components A and B simultaneously or can be done one after the other. In the case of successive treatment, it must be ensured that the two components can interact. This is ensured by sufficiently short time intervals between the treatments with the individual components. More detailed information on this follows below.

Component A should be liquid at 20 ° C. “Liquid at 20 ° C” in this context means that component A at 20 ° C and a shear rate of 1 s ^{1 has} a dynamic viscosity, determined according to DIN 53019-1: 2008-09, of a maximum of 200 mPas.

Fatty acid triglycerides are the triple esters of glycerol with fatty acids. The liquid mixtures of fatty acid triglycerides are in particular vegetable oils, provided they have the required viscosity properties; however, synthetic mixtures are also suitable.

Suitable vegetable oils are, for example, rapeseed oil, sunflower oil, corn oil, soybean oil, cottonseed oil, peanut oil, olive oil, safflower oil, hemp oil, palm olein, mixtures thereof and mixtures of at least one of the aforementioned oils with palm oil or coconut oil. The vegetable oils can be used in both native and refined form.

Refined vegetable oils are those obtained from conventional refining processes. During the refining process, the oils are chemically or physically cleaned by degumming, neutralization, bleaching, deodorization, optionally de-lecithination and optionally winterization (removal of waxes and high-boiling triglycerides). For the purposes of the present invention, native vegetable oils are those that are not subjected to refining.

Palm olein is the name given to the liquid part that is obtained from the separation of palm oil by fractionation (usually fractional crystallization). Refined palm oil is often used in the fractionation or the palm olein obtained through the fractionation is then refined in order to remove color and odor. Palm olein complies with the present requirement for component A, i.e. it is liquid at 20 ° C.

In trade and industry, the term “palm oil” is sometimes used vaguely and also includes palm oil fractions such as palm olein. In the context of the present invention, however, this term is only used for unfractionated palm oil.

It may be useful to add conventional antioxidants to stabilize the vegetable oils.

In the context of the present invention, the term “silica” is used for polymeric silica and not, for example, for orthosilicic acid or oligosilicic acids. More precisely, it refers to polymeric silicas with a cross-linked structure, which should actually be more correctly referred to as silicic acid anhydride or silicon dioxide (English silica). However, since such products continue to be marketed by industry under the name of silica, they are also called that in the context of the present invention.

Amorphous silicas are non-crystalline silicas (ie they do not have an ordered Si-O crystal lattice) and are - more correctly - also referred to as amorphous silicon dioxide. In the context of the present invention, the term does not include glasses or kieselguhr (in the sense of radiolarian skeletons and diatomaceous earth). The amorphous silicas belong in the context of the present invention Wet processes, in particular by precipitation, or silicas produced by thermal processes, such as precipitated silica (precipitated silicon dioxide) and fumed silica (fumed silicon dioxide). The silicas can be used both in a hydrophilic and in a hydrophobized form.

Hydrophilic silicas are untreated silicas; more precisely, non-hydrophobic silicas. In hydrophilic silicas there are free silanol groups (SiOH). In contrast to this, in hydrophobic silicas, at least some of the silanol groups are converted into hydrophobic groups. Hydrophobization can be achieved, for example, by reacting hydrophilic silica with silanes, siloxanes, polysiloxanes or waxes, for example with dimethyldichlorosilane (DDS), hexamethyldisilazane (HMDS), octamethylcyclotetrasiloxane (OMS; OMCTS; D4) or polydimethylsiloxane (PDMS). Hydrophobized silicas typically have a carbon content, determined in accordance with DIN EN ISO 3262-19: 2000-10, of at least 0.5% by weight, in particular at least 1% by weight, based on the total weight of the silica.

Conversely, however, this does not necessarily mean that hydrophilic silicas do not contain any carbon, since impurities with carbon-containing components can occur from the silica source or from its processing. Hydrophilic silicas within the meaning of the present invention, however, have a carbon content, determined in accordance with DIN EN ISO 3262-19: 2000-10, of less than 0.5% by weight, preferably less than 0.2% by weight, in particular of less than 0.1% by weight, especially from about 0% by weight, based on the total weight of the silica. The term “approximately” 0% by weight is intended to take any measurement inaccuracies into account.

In this context, the term carbon content means the content of organic carbon, as it is introduced, for example, through the hydrophobization. Any carbon introduced by adsorbed CO2 or other inorganic carbon sources such as carbonates is not included in the stated carbon contents.

“Mass ratio”, “weight ratio” and “quantity ratio” are used synonymously in the context of the present invention.

Linear Ce-C22-alkyl is, for example, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n -Hexadecyl, n- Heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, n-henicosyl or n-docosyl. Linear Cn-Ci7-alkyl is, for example, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl or n-heptadecyl.

Preferred Embodiments

Component A is preferably selected from vegetable oils, which of course must meet the above requirement (liquid at 20 ° C.). Suitable vegetable oils and vegetable oil mixtures are mentioned above.

In addition to the chain length of the hydrocarbon radical of the fatty acids, the viscosity of the vegetable oils is mainly influenced by whether the hydrocarbon radical is saturated or unsaturated and how many C-C double bonds are contained in the rest. The higher the proportion of unsaturated fatty acids in the oils and the more double bonds in the hydrocarbon residues, the lower the viscosity.

Accordingly, particularly preferred among the vegetable oils are those with a Wijs iodine number in the range from 20 to 160, preferably from 50 to 160, in particular from 100 to 150, determined according to DIN 53241-1: 1995-05. In vegetable oil mixtures, at least one of the vegetable oils contained therein preferably has the above-mentioned iodine number. In particular, however, all vegetable oils contained in the mixture have the above-mentioned iodine number.

At 20 ° C. and a shear rate of 1 s ^1, component A preferably has a dynamic viscosity, determined according to DIN 53019-1: 2008-09, in the range from 20 to 200 mPas, particularly preferably from 20 to 150 mPas and in particular from 30 to 100 mPas.

Component A is preferably selected from rapeseed oil, sunflower oil, corn oil, soybean oil, cottonseed oil, peanut oil, olive oil, safflower oil, hemp oil, palm olein, mixtures of the aforementioned oils and mixtures of at least one of the aforementioned vegetable oils with palm oil and / or coconut oil. In particular, component A is selected from rapeseed oil, sunflower oil, soybean oil, palm olein, mixtures of at least two of the aforementioned oils and mixtures of at least one of the aforementioned vegetable oils with palm oil and / or coconut oil. If mixtures of the aforementioned vegetable oils with palm oil and / or coconut oil are used, the weight ratios are of course chosen so that the mixture is liquid at 20 ° C. As a rule, the mixture is at most 80% by weight, preferably at most 70% by weight, in particular at most 60% by weight and especially at most 55% by weight palm oil and / or coconut oil, based on the weight of the mixture of the above Vegetable oil and palm oil / coconut oil.

The vegetable oils can be used in both native and refined form.

Palm olein and palm oil are often used in a refined form, as their natural color and smell can be disruptive.

Component B is an amorphous silica. As explained above, amorphous silicas are non-crystalline, i.e. they do not have an ordered Si-O crystal lattice. Suitable amorphous silicas have a relatively high specific surface area. Suitable amorphous silicas can be obtained by wet processes, in particular by precipitation, or by thermal processes, such as flame hydrolysis.

The amorphous silicas are preferably highly dispersed and have a specific surface, determined by nitrogen adsorption according to the BET method according to DIN ISO 9277: 2014-01 at 77.3 K, of preferably at least 50 m ² / g, in particular from 80 to 600 m ² / g , particularly preferably from 100 to 600 m ² / g, especially from 150 to 400 m ² / g and very especially from 150 to 300 m ² / g.

The amorphous silicas are preferably selected from pyrogenic silica, precipitated silica and mixtures thereof.

Fumed silica is produced by flame hydrolysis of silicon tetrachloride. Silicon tetrachloride is burned in the gas phase with hydrogen and air with a burner in a cooled combustion chamber. First, droplet-shaped silicon dioxide particles are formed in the flame, which attach to one another in a chain-like manner and form three-dimensional secondary particles via branches; these in turn accumulate to form tertiary particles.

Precipitated silica is produced by precipitation with sulfuric acid from water glass solution. Precipitated silicas and pyrogenic silicas generally differ in that the former have a somewhat broader particle size distribution and a somewhat higher tapped density, determined in accordance with DIN EN ISO 787-11: 1995-10, than the latter.

The silicas can be used both in a hydrophilic and in a hydrophobized form. In the process according to the invention and in the oil composition according to the invention, however, the silicas are used in hydrophilic form.

However, hydrophilic silicas are also more preferred for use in the present invention.

The amorphous silicas are commercially available. Suitable precipitated silicas are, for example, the Sipernat®, Ultrasil® and Sident® products from Evonik and the LoVel® and HiSil® products from DuPont. Suitable pyrogenic silicas are, for example, the Aerosil®, Aerodisp®, Aeroxid® and Aeroperl® products from Evonik and the HDK® products from Wacker Chemie AG. Suitable silicas are also the Syloid® products from Grace, the Sylysia® products from Fuji, the Köstrosorb® products from Chemiewerke Bad Köstritz, the Gasil® and NeoSyl® products from Ineos and the Cab-0-Sil ® products from Cabot.

The following Aerosil® products should be emphasized as examples of hydrophilic pyrogenic silicas (the respective BET surface area is given in brackets; the pH is between 3.5 and 5.5): Aerosil® 90 (90 ± 15 m ² / g), Aerosil® 130 (130 ± 25 m ² / g), Aerosil® 150 (150 ± 15 m ² / g), Aerosil® 200 (200 ± 25 m ² / g), Aerosil® 255 (255 ± 25 m ² / g), Aerosil® 300 (300 ± 30 m ² / g), Aerosil® 380 (380 ± 30 m ² / g), Aerosil® OX 50 (50 ± 15 m ² / g), Aerosil® TT 600 (200 ± 50 m ² / g), Aerosil® 200 F (200 ± 25 m ² / g), Aerosil® 380 F (380 ± 30 m ² / g), Aerosil® 200 Pharma (200 ± 25 m ² / g ), Aerosil® 300 Pharma (300 ± 25 m ² / g).

The following Sipernat® products should be emphasized as an example of hydrophilic precipitated silicas (the respective BET surface area is indicated in brackets - as far as it is known): Sipernat® FPS-101, Sipernat® 11 PC, Sipernat® 120 (approx. 125 m ² / g), Sipernat® 160 (approx. 165 m ² / g), Sipernat® 186 (approx. 195 m ² / g), Sipernat® 218 (approx. 160 m ² / g), Sipernat® 22 (approx. 190 m ² / g), Sipernat® 22 LS (approx. 180 m ² / g), Sipernat® 22 PC, Sipernat® 22 S (approx. 190 m ² / g), Sipernat® 22 S ex Thailand, Sipernat® 2200 (approx. 190 m ² / g), Sipernat® 2200 PC, Sipernat® 236 (approx. 180 m ² / g), Sipernat® 238 (approx. 195 m ² / g), Sipernat® 25 (approx. 190 m ² / g), Sipernat® 266 (approx. 160 m ² / g), Sipernat® 268 (approx. 180 m ² / g), Sipernat® 288 (approx. 200 m ² / g), Sipernat® 298 (approx. 210 m ² / g), Sipernat® 303 (approx. 565 m ² / g), Sipernat® 310 (approx. 700 m ² / g), Sipemat® 320 (approx. 180 m ² / g), Sipernat® 320 DS (approx. 175 m ² / g), Sipernat® 325 AP (approx. 130 m ² / g), Sipernat® 325 C (approx. 130 m ² / g), Sipernat® 325 E, Sipernat® 33, Sipernat® 340 (approx. 175 m ² / g), Sipernat® 35 (approx. 170 m ² / g), Sipernat® 350 (approx. 55 m ² / g), Sipernat® 383 DS (approx. 175 m ² / g), Sipernat®

50 (approx. 500 m ² / g), Sipernat® 50 S (approx. 500 m ² / g), Sipernat® 500 LS (approx. 500 m ² / g), Sipernat® 609, Sipernat® 612, Sipernat® 622 , Sipernat® BG-2, Sipernat® FPS-5.

As an example of hydrophobic silicas, the following Sipernat® products should be emphasized (the respective BET surface area is - as far as known - indicated in brackets): Sipernat® D 10, Sipernat® D 13, Sipernat® D 17 (approx. 100 m ² / G).

Specific examples of suitable silicas are Aerosil® 200, Aerosil® 200 F, Sipernat® 22, Sipernat® 22 LS, Sipernat® 22 PC, Sipernat® 22 S, Sipernat® 22 S ex Thailand and Sipernat® D 17 and in particular Aerosil® 200 F, Sipernat® 22 S and Sipernat® D 17 highlighted. Among these, Aerosil® 200, Aerosil® 200 F, Sipernat® 22, Sipernat® 22 LS, Sipernat® 22 PC, Sipernat® 22 S and Sipernat® 22 S ex Thailand and in particular Aerosil® 200 F and Sipernat® 22 S are preferred.

Component A and component B are preferably used in a mass ratio of A to B in the range from 40: 1 to 5: 1, particularly preferably from 30: 1 to 7: 1, in particular in the range from 27: 1 to 8: 1 and especially used in the range from 25: 1 to 9: 1.

The combination comprising components A and B consists preferably of at least 80% by weight, in particular at least 85% by weight, based on the total weight of the combination, of components A and B. The other constituents, if present, are in the Usually anti-caking agents and possibly technical impurities. If no anti-caking agent is used, the combination comprising components A and B is preferably at least 90% by weight, particularly preferably at least 95% by weight, in particular at least 98% by weight, especially at least 99% by weight , based on the total weight of the combination, consisting of components A and B.

Anti-caking agents are substances that prevent or reduce the formation of lumps, caking or hardening of powdery or granular substances. Suitable anti-caking agents are those that are commonly used in solid fertilizer formulations. These are, for example, fatty amines, alkoxylated fatty amines, fatty amine acetates, Mixtures of fetamines with fatty alcohols, fatty acids or mixtures of the aforementioned compounds. In this context, the fetamines (also in the form of their derivatives) are compounds R-NH2, where R stands for a long-chain alkyl radical, usually a linear alkyl radical, mostly linear C6-C22-alkyl. Alkoxylated fetamines can be obtained by reacting fatty amines with ethyl oxide (EO) and / or propylene oxide (PO), for example with 2 to 20 mol, especially 4 to 15 mol, EO and / or PO per mol of amine. In this context, the fatty alcohols are compounds R — OH, in which R stands for a long-chain alkyl radical, usually a linear alkyl radical, usually linear C6-C22-alkyl. In this context, the fatty acids are compounds RC (= 0) 0H, where R is a long-chain alkyl radical, usually a linear alkyl radical, usually linear C11-C17-alkyl.

Without wishing to be bound by theory, it is assumed that the amorphous silica changes the theological behavior of the triglycerides, thickening them and thus preventing them from being absorbed by the granulate immediately after being applied and therefore only contributes to a limited extent to the suppression of dust development can. This effect is particularly pronounced in the case of highly dispersed silicas. By preventing or reducing absorption, the triglyceride remains on the surface and can develop its dust-suppressing effect. Surprisingly, this effect is retained even if the granulate is still warm during the treatment and, for example, has a temperature of up to 60 ° C or even up to 70 ° C or up to 80 ° C.

Surprisingly, this effect is observed not only when the granules are treated with a mixture of components A and B, but also when components A and B are applied separately. The components can be applied simultaneously or one after the other. In the case of successive treatment, it is of course necessary that this takes place within a sufficiently short period of time so that the individual components can still interact.

In the process according to the invention, components A and B can therefore be used for treating the granulate as a mixture or separately, simultaneously or in succession.

In one embodiment, the granules are treated with a mixture (a composition) containing components A and B. In an alternative embodiment, components A and B are used separately for treating the granules, the granules being treated with component A and component B at the same time.

In a further alternative embodiment, components A and B for treating the granules are used separately and one after the other; i.e. the granulate is not treated with components A and B at the same time, but one after the other. The time interval between the treatment with component A and the treatment with component B is preferably at most 2 minutes, particularly preferably at most 1 minute and in particular at most 30 seconds. The order of successive treatment is basically arbitrary; for practical reasons, however, it is preferred to treat the granules first with component A and then with component B.

If components A and B are used in a mixture, it is preferred to use them in the form of an oil composition that contains a) 75 to 97.6% by weight, preferably 83.3 to 97.6% by weight, particularly preferably 87 5 to 96.8% by weight, in particular 88.9 to 96.4% by weight, especially 88.9 to 96.2% by weight, based on the total weight of the oil composition, of component A; and b) 2.4 to 25% by weight, preferably 2.4 to 16.7% by weight, particularly preferably 3.2 to 12.5% by weight, in particular 3.6 to 11.1% by weight. -%, especially 3.8 to 11.1% by weight, based on the total weight of the oil composition which contains component B.

The treatment of the granules is preferably carried out by spraying, dropping or running the mixture / oil composition onto the granules. Contrary to the expectation that a mixture of components A and B would make a spraying process difficult or even impossible due to the thickening effect of component B on component A due to the greatly increased viscosity, even spraying processes can be used very well because the mixture is shear-thinning. This means that at higher shear rates, as usually occur in spray processes, the viscosity of the mixture drops so much that the mixture can be sprayed.

The oil composition preferably has a dynamic viscosity of at least 500 mPas at 20 ° C. and a shear rate of 1 s ¹ , and at 20 ° C. and a shear rate of 300 s ¹ a dynamic viscosity that is at least 200 mPas. half of the dynamic viscosity of the oil composition is at 20 ° C. and a shear rate of 1 S ¹ , the viscosity values being determined in accordance with DIN 53019-1: 2008-09.

It is easier, however, to use components A and B separately, simultaneously or in succession, since this procedure does not depend on the viscosity during spraying.

In the case of the successive treatment, component A is preferably first sprayed onto the granules or allowed to drip or run into the granules and then mixed with component B, which can be done, for example, using conventional stirrers and mixers. Suitable mixers are, for example, tumble mixers with and without internals such as drum mixers and ring mixers, paddle mixers such as trough mixers, plow-paddle mixers and twin-shaft mixers, and screw mixers, mixing boxes and other known mixing devices.

The simultaneous but separate treatment with components A and B can be done, for example, by mixing the granulate with the solid (powdery) component B and at the same time spraying it with the liquid component A or allowing it to drip or run into the mixer during the mixing process .

Components A and B are preferably used in a total amount of from 1 to 10 kg per ton of granules, in particular from 2 to 7 kg per ton of granules.

If the combination also contains anti-caking agents, these can be used in a mixture with one or both components A and B or separately from these. For purely practical reasons, they are used in particular in a mixture with component A.

If anti-caking agents are used, they are preferably used in a total amount of 100 to 500 g per ton of granules, in particular from 200 to 350 g per ton of granules.

The granules to be treated are granules based on inorganic salts or based on urea. In particular, these are fertilizer granules, more precisely inorganic fertilizer granules which contain inorganic salts and / or urea, which are the inorganic salts are those that are suitable as fertilizers. The method according to the invention is suitable for any granulate shapes and types and is not restricted to specific types.

The inorganic salts that are suitable as fertilizers usually contain at least one of the following elements (macronutrients): potassium, nitrogen, phosphorus, magnesium, sulfur and calcium. Potassium, magnesium and calcium are usually present as potassium, magnesium or calcium chlorides or sulphates; but they can also occur as a secondary component as carbonates or oxides. They can also occur as nitrates or phosphates. Nitrogen is usually in the form of ammonium or nitrate. Phosphorus is usually in the form of phosphate. Sulfur is usually in the form of sulfate or elemental.

The fertilizer granules are therefore preferably those 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 abovementioned salts, based on urea, in particular pressed urea, or based on a mixture of at least one of the abovementioned salts or mixed salts with urea. "Based on" is intended to make it clear that the granules can also contain other components, for example the already mentioned oxides and carbonates and / or the micronutrients mentioned below and possibly other components that are used in the production of granules, such as binders, dyes, etc. Mixed salts are salts with several different cations or different anions, for example double salts (salts with two different cations or two different anions), triple salts (salts with three different cations or three different anions) etc.

As already mentioned, mixed salts are salts with several different cations or different anions. They arise when different salts are dissolved in a solution and these crystallize together in a regular crystal structure. In aqueous solution they dissociate into their individual ions. Double salts are salts with two different cations or two different anions; Triple salts are salts with three different cations or three different anions. In the present case, the mixed salts are in particular those with different cations. Examples of suitable salts are potassium sulfate, potassium chloride, magnesium sulfate, magnesium chloride, magnesium oxide, calcium sulfate, calcium chloride, calcium carbonate, calcium oxide, calcium nitrate, potassium nitrate, ammonium nitrate, ammonium sulfate, mono- and di-ammonium phosphate, calcium phosphate and mixtures thereof. Mixed salts (especially double or triple salts) which are built up from the above-mentioned compounds, such as polyhalite (K ₂ Ca ₂ Mg [S0 ₄ ] ₄ -2H20), carnallite (KMgCl3-6H20), schoenite (syn. Picromerite), are also suitable ; K ₂ Mg [S0 ₄ ] ₂ -6H ₂ 0), leonite (K ₂ Mg (S0 ₄ ) ₂ -4H ₂ 0), langbeinite (K2Mg2 [SC> 4] 3), syngenite (K2Ca [S04] 2- H20) and the like.

In addition to the macronutrients mentioned above, the fertilizers can also contain micronutrients such as boron, copper, iron, manganese, molybdenum, nickel and zinc. These are typically used in the granules in the form of their salts or complex compounds. Manganese, copper and zinc are mostly used in the form of their sulfates. Copper and iron are also used in the form of chelates, e.g. B. with EDTA, used or as oxides. Boron is commonly referred to as calcium sodium borate, e.g. B. used in the form of ulexite, sodium borate, potassium borate or boric acid. Molybdenum is often used as sodium or ammonium molybdate or a mixture thereof. Typically, the proportion of micronutrients other than boron, calculated in their elemental form, will not exceed 1% by weight, based on the total mass of the granulate. The boron content, calculated as B2O3, will generally not exceed 3% by weight and, if present, is typically in the range from 0.01 to 3% by weight, in particular 0.01 to 2% by weight, based on the total mass of the components of the granulate.

Suitable salts and salt mixtures are commercially available and are known, for example, under the following product names: SOP (main component: potassium sulfate; in addition, small amounts of calcium and magnesium sulfate and potassium and sodium chloride); MOP (main component: potassium chloride; in addition small proportions of sodium and magnesium chloride as well as magnesium, potassium and calcium sulphate), corn potash from K + S (main constituent: potassium chloride; besides magnesium sulphate and sodium chloride; also small proportions of magnesium chloride as well as potassium and calcium sulphate) , Patentkali from K + S (main constituent: potassium sulphate; besides magnesium sulphate; as well as leonite and langbeinite; also small amounts of calcium sulphate and other sulphates as well as potassium and sodium chloride), kieserite (main constituent: magnesium sulphate monohydrate or 5/4 hydrate), NPK - fertilizer, MAP (monoammonium phosphate); DAP (diammonium phosphate), CAS (calcium ammonium nitrate; mixture of ammonium nitrate and calcium carbonate); TSP (triple superphosphate). Granules that are not commercially available are of course also suitable. Urea-based granules, in particular pressed urea granules, are also known.

Granules which contain both inorganic salts and urea are also suitable. A number of NPK granulates contain such combinations.

The granules can have any shape and morphology and can be obtained by various processes. Press granules, rolling granules and spray granules are only mentioned as catchwords. Details on their production have already been described above.

The granules based on inorganic salts can, however, also be produced by processes known per se for producing granules from finely divided inorganic salts, such as those described, for example, in Wolfgang Pietsch, Agglomeration Processes, Wiley-VCH, 1st edition, 2002, in G. Heinze, Handbuch der Agglomerationstechnik, Wiley-VCH, 2000 and in Perry's Chemical Engineers' Handbook, 7th Edition, McGraw-Hill, 1997, pp. 20-56 to 20-89. Both build-up and breakdown agglomeration processes are suitable.

The particle size (grain size) of the granulate particles is generally in the range from 1 to 10 mm. The proportion of granulate particles with a grain size of less than 1 mm is usually small and is, for example, less than 10% by weight, in particular less than 5% by weight. Preferably at least 60% by weight, in particular at least 80% by weight and especially at least 90% by weight of the granulate particles have a grain size in the range from 2 to 5 mm. It is advantageous if less than 10% by weight of the granulate particles have a grain size below 2 mm. The grain size is determined by sieving according to DIN EN 1235 with a square mesh according to DIN ISO 3310-1. The distribution of the grain sizes of the granulate particles can be determined in a manner known per se by sieve analysis.

The process according to the invention leads to a significantly reduced generation of dust when handling granules. The reduced development of dust can be recognized qualitatively visually if samples of the granules obtained according to the invention and samples of untreated are, for example, vigorously shaken and the development of dust is compared. The effect can be quantified, for example, with the test method described in the examples. Components A and B can be applied to the granulate in a simple manner without complex process steps. It is not necessary to heat the components, especially component A or the mixture of components A and B; Component A or mixtures of components A and B can be used at room temperature (20-25 ° C.) or even at lower temperatures for treating the granules, which significantly reduces the expenditure on equipment and energy.

Another advantage of the method according to the invention compared to the use of mineral oils as dust binders or pure vegetable oils or vegetable oil mixtures is that components A and B can be applied to warm granules, for example fresh from the manufacturing process. This does not work with vegetable oils or with unthickened or slightly thickened mineral oils as these are immediately absorbed by the granules. High-melting mineral oils can be applied to warm granules, but these mineral oils have to be heated, which is associated with a lot of equipment and energy expenditure. With the combination of components A and B according to the invention, however, this succeeds.

The invention also relates to the use of a combination comprising a) at least one fatty acid triglyceride which is liquid at 20 ° C. or at least one mixture of fatty acid triglycerides which is liquid at 20 ° C. as component A; b) at least one amorphous silica as component B, where in the combination the mass ratio of component A to component B is in the range from 40: 1 to 3; 1, as a dust binder for granules based on inorganic salts or for urea granules, in particular for fertilizer granules.

The statements made in relation to the method according to the invention with regard to suitable and preferred configurations apply here accordingly. It should only be mentioned that in this connection the amorphous silica can be used both in a hydrophilic and in a hydrophobicized form, the hydrophilic form being preferred.

The invention also relates to an oil composition containing a) 75 to 97.6% by weight, based on the total weight of the oil composition, of a fatty acid triglyceride liquid at 20 ° C. or at least one mixture of fatty acid triglycerides liquid at 20 ° C., as component A, wherein the Component A has a dynamic viscosity, 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 · ^1; and b) 2.4 to 25% by weight, based on the total weight of the oil composition, of at least one amorphous, hydrophilic silica as component B.

The statements made in connection with the method according to the invention regarding preferred configurations of components A and B apply here accordingly.

Accordingly, component A is preferably selected from vegetable oils which of course meet the above requirement (liquid at 20 ° C. and dynamic viscosity, determined according to DIN 53019-1: 2008-09, at 20 ° C. and a shear rate of 1 s- ¹ in the range of 20 to 200 mPas).

Among the vegetable oils and vegetable oil mixtures, preference is given to those having a Wijs iodine number in the range from 20 to 160, preferably from 50 to 160, in particular from 100 to 150, determined according to DIN 53241-1: 1995-05.

At 20 ° C. and a shear rate of 1 s ^-1, component A preferably has a dynamic viscosity, determined according to DIN 53019-1: 2008-09, in the range from 20 to 150 mPas and in particular from 30 to 100 mPas.

Component A is preferably selected from rapeseed oil, sunflower oil, corn oil, soybean oil, cottonseed oil, peanut oil, olive oil, safflower oil, hemp oil, palm olein, mixtures of the aforementioned oils and mixtures of at least one of the aforementioned vegetable oils with palm oil and / or coconut oil. In particular, component A is selected from rapeseed oil, sunflower oil, soybean oil, palm olein, mixtures of at least two of the aforementioned oils and mixtures of at least one of the aforementioned vegetable oils with palm oil and / or coconut oil.

Component B is an amorphous silica. Suitable amorphous silicas have a relatively high specific surface area. They can be obtained by wet processes, in particular by precipitation, or by thermal processes such as flame hydrolysis. The silicas are used in a hydrophilic form.

The amorphous silicas are preferably highly dispersed and have a specific surface area, determined by nitrogen adsorption according to the BET method according to DIN ISO 9277: 2014-01 at 77.3 K of preferably at least 50 m ² / g, particularly preferably from 80 to 600 m ² / g, in particular from 100 to 600 m ² / g, especially from 150 to 400 m ² / g and very specifically from 150 to 300 m ² / g.

The amorphous silicas are commercially available. Suitable commercial products are mentioned above. In this context, too, special examples of particularly suitable silicas are Aerosil® 200, Aerosil® 200 F, Sipernat® 22, Sipernat® 22 LS, Sipernat® 22 PC, Sipernat® 22 S and Sipernat® 22 S ex Thailand and in particular Aerosil® 200 F and Sipernat® 22 S highlighted.

In a particularly preferred group 1 of embodiments of the oil compositions claimed according to the invention, component B is selected from precipitated silicas and mixtures thereof with pyrogenic silicas, with the proviso that component B in preferred group 1 is at least 50% by weight, in particular at least 80% by weight .-%, based on the total mass of component B, comprises at least one precipitated silica.

In a further particularly preferred group 2 of embodiments of the oil compositions claimed according to the invention, component B is selected from pyrogenic silicas and mixtures thereof with precipitated silicas, with the proviso that component B in preferred group 2 is more than 50% by weight, in particular at least 80 % By weight, based on the total mass of component B, comprises at least one pyrogenic silica.

In a further particularly preferred group 2a of embodiments of the oil compositions claimed according to the invention, component B is contained in the oil composition in an amount of at least 6.5% by weight, based on the total weight of the oil composition, if component B is selected from pyrogenic silicas is.

The oil composition preferably contains 83.3 to 97.6% by weight, based on the total weight of the oil composition, of component A, and 2.4 to 16.7% by weight, based on the total weight of the oil composition, of component B The oil composition particularly preferably contains 87.5 to 96.8% by weight, based on the total weight of the oil composition, of component A, and 3.2 to 12.5 % By weight, based on the total weight of the oil composition, of component B. In particular, the oil composition contains 88.9 to 96.4% by weight, based on the total weight of the oil composition, of component A, and 3.6 to 11, 1% by weight, based on the total weight of the oil composition, of component B. Specifically, the oil composition contains 88.9 to 96.2% by weight, based on the total weight of the oil composition, component A, and 3.8 to 11 , 1% by weight, based on the total weight of the oil composition, of component B.

The oil composition contains component A and component B in a mass ratio of A to B in the range from 40: 1 to 3: 1, particularly preferably from 40: 1 to 5: 1, more preferably from 30: 1 to 7: 1, in particular from 27: 1 to 8: 1 and especially from 25: 1 to 9: 1.

In groups 1, 2 and 2a of embodiments, components A and B according to the invention preferably make up a total of at least 80% by weight, in particular at least 85% by weight, of the total oil composition. The other components, if any, are usually anti-caking agents and possibly technical impurities. If no anti-caking agent is used, components A and B according to the invention preferably make up at least 90% by weight, particularly preferably at least 95% by weight, more preferably at least 99% by weight, in particular at least 99.5% by weight and special at least 99.9% by weight of the total oil composition.

With regard to suitable anti-caking agents, reference is made to the statements above.

The oil composition is preferably shear thinning. This means that at high shear rates, as usually occur, for example, in spraying processes, the viscosity of the mixture drops so much that the mixture can be sprayed. In particular, the viscosity of an oil composition according to the invention at 20 ° C. and a shear rate of 1 s ¹ is at least a factor of 1.2, in particular at least a factor of 1.5, higher than the viscosity of this oil composition at 20 ° C. and a shear rate of 300 s ^1st The viscosity of the oil composition according to the invention at 20 ° C. and a shear rate of 300 s ^{1 will} preferably not exceed a value of 700 mPas and in particular a value of 500 mPas and is preferably in the range from 100 to 700 mPas and in particular in the range from 110 to 500 mPas. The viscosities are the values determined in accordance with DIN 53019-1: 2008-09 at 20 ° C. using a rotational viscometer with a plate-plate measuring system with a plate / plate distance of 1 mm (plate diameter 6 mm) at the specified shear rate.

Finally, the invention relates to a granulate which can be obtained by the method according to the invention.

The statements made in connection with the method according to the invention and the oil composition according to the invention regarding preferred configurations of components A and B and the granules apply here accordingly.

The granules contain components A and B in a total amount of preferably 1 to 10 kg per ton of (untreated) granules, in particular from 2 to 7 kg per ton of (untreated) granules. Components A and B are present in the above-mentioned general or preferred mass ratios.

"Untreated granulate" refers to the granulate as it was before the treatment with components A and B.

The granulate according to the invention accordingly preferably contains 750 g to 9.76 kg of component A and 24 g to 2.5 kg of component B per ton, with components A and B in the general or preferred mass ratios given above (40: 1 to 3: 1, preferably 40: 1 to 5: 1, particularly preferably 30: 1 to 7: 1, in particular 27: 1 to 8: 1 and especially 25: 1 to 9: 1). In particular, the granules contain 1.50 kg to 6.83 kg of component A and 49 g to 1.75 kg of component B per ton, with components A and B in the general or preferred mass ratios given above (40: 1 to 3: 1, preferably 40: 1 to 5: 1, particularly preferably 30: 1 to 7: 1, in particular 27: 1 to 8: 1 and especially 25: 1 to 9: 1).

The granules according to the invention have a significantly reduced dust development than granules not treated according to the invention and at the same time have no negative change in flow behavior; ie it does not stick and clump more than granules that have not been subjected to the method according to the invention. In addition, it does not release any components that are difficult to break down or otherwise environmentally relevant into the environment. The invention is illustrated by the following examples.

Examples

The following oils were used:

Rapeseed oil

Sunflower oil

Soybean oil

RBD palm oil from Olenex (RBD = refined bleached deodorized)

RBD Palm-Olein 64 SG from Olenex (refined palm-olein; RBD = refined bleached deodorized)

The following silica products were used:

Sipernat® 22 S from Evonik Sipernat® 50 from Evonik Sipernat® D 17 from Evonik Aerosil® 200 F from Evonik

In addition, quartz sand as another source of silicon and precipitated calcium carbonate were tested for comparison.

The following products were used as fertilizer granules:

SOP:

Press granulate

Grain size 2 - 4 mm (80 - 90%)

D ₅₀ typically 2.8 mm Chemical composition:

K2SO ₄ typically 93.5%

Other sulfates (MgS0 ₄ , CaS0 ₄ ) typically 3%

Chloride (KCl, NaCI) typically 1.5%

Other (mainly crystal water) typically 2%

MOP:

Press granulate

Grain size 2 - 4 mm (85 - 95%)

D ₅₀ typically 2.8 mm Chemical composition:

KCl typically 95.4%

Secondary constituents (NaCl, MgCl ₂ , MgS0 ₄ , K2SO4, CaS0 ₄ ) typically 4.4% Adhesive moisture typically 0.2%

Kornkali:

Press granulate

Grain size 2 - 5 mm (approx. 94%)

D ₅ o typically 3.4 mm Chemical composition:

KCl typically 63.5%

NaCI typically 9.5%

MgS0 ₄ typically 17.0%

MgCl ₂ , K ₂ S0 ₄ , CaS0 ₄ typically 5.5%

Other (mainly crystal water) typically 4.5%

Patent potash:

Roll granulate

Grain size 2 - 5 mm (approx. 92%)

D50 typically 3.1 mm Chemical composition:

K ₂ S0 ₄ typically 50.5%

MgS0 typically 30.5%

Other sulfates (CaS0 etc.) typically 1.5%

Chloride (KCl, NaCI) typically 5.5%

Other (mainly crystal water) typically 12%

NPK:

Grain size 2 - 4 mm (approx. 95%)

D ₅ o typically 3.2 mm Chemical composition:

K ₂ 0 typically 15%

N (ammonium) typically 15%

P ₂ O _s (phosphate) typically 13%

S (sulfate) typically 11%

Chloride typically 12% 1) Rheological investigation of the starting materials

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

The dynamic viscosity of the oils is shown in Table 1.

Table 1

Various mixtures of rapeseed oil and amorphous silicas or quartz sand as another source of silicon or precipitated calcium carbonate were produced in different weight ratios and their viscosity was measured.

Table 2 shows the viscosity behavior of mixtures of rapeseed oil with various amorphous silicas or quartz sand or precipitated calcium carbonate in a weight ratio of 11: 1.

Table 2 Mixtures of the invention as we see, are thickened, but behave shear thinning how (s ^_1 compared to the viscosity at a shear rate of 1) can recognize the significantly lower viscosity at a shear rate of 300 S ^1st Table 3 shows the viscosity behavior of mixtures of different oils with Sipernat® 22 S in a weight ratio of 11: 1.

Table 3 Table 4 shows the viscosity behavior of mixtures of different oils with Aerosil® 200 F in a weight ratio of 22: 1.

Table 4 Table 5 shows the viscosity behavior of mixtures of rapeseed oil with Sipernat® 22 S in various weight ratios.

Table 5

As you can see, with a weight ratio of 110: 1 the thickening effect of Sipernat® 22 S is negligible. Table 6 shows the viscosity behavior of mixtures of rapeseed oil with Aerosil® 200 F in various weight ratios.

Table 6 As you can see, at a weight ratio of 110: 1 the thickening effect of Aerosil® 200 F is not very pronounced.

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 7

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 8

2) granule treatment

Unless otherwise described, the granulate was first treated with oil and homogenized for 15 seconds. Component B was then added and the mixture was homogenized for a further 45 seconds. The temperature that the granules had during the treatment (between 25 and 60 ° C.) is given below.

3) Investigation of the dust behavior

After one and after three weeks of storage, 100 g of granulate samples were initially stressed by shaking using an overhead shaker (comparable to the product from Gerhard RA 20) for 5 minutes in a bottle (30 cm high; diameter 8 cm) (approx 40 rpm).

The dust number was then determined with a DustView II from PALAS.

Here, after a 50 cm drop, the attenuation of a laser beam is measured after 0.5 and 30 s. For this, a sample is placed on a sample funnel. By opening a flap, the sample falls into a dust room, causing dust to stir up and weaken the laser beam. The attenuation is expressed as a dust value, whereby a value of 0 means that the laser beam is not shadowed (i.e. no or only marginal dust), and a value of 100 stands for complete shadowing of the laser beam by the swirling of dust. The dust number corresponds to the sum of the dust value after 0.5 s and the dust value after 30 s after the impact. The aim is to have a dust number below 0.5, better below 0.3 or even below 0.2.

The dust numbers given below correspond to the mean value of 4 measurements from 4 samples. 3.1) SOP granules (broken granules)

The temperature of the basic granulate (= untreated SOP granulate) was 40 ° C. during the granulate treatment (see FIG. 2)).

Table 9 shows the dust behavior of granules obtained by treating SOP broken granules with rapeseed oil and various silicas in a weight ratio of 11: 1 after storage for 1 or 3 weeks. The amounts of oil and silica used per ton of base granulate are given. For comparison, the basic granulate was examined 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 9 SOP As can be seen, the treatment according to the invention leads to the most effective suppression of dust generation. The sole use of amorphous silicas, such as Sipernat 22 S, Sipernat 50, Sipernat D 17 or Aerosil 200 F, does not lead to a reduction in the dust number.

Table 10 shows the dust behavior of granules obtained by treating SOP broken granules with various oils and with Sipernat® 22 S or Aerosil® 200 F in a weight ratio of 11: 1 after storage for 1 or 3 weeks. The amounts of oil and silica used per ton of base granulate are given. For comparison, the basic granulate was examined in an untreated form and in a form treated only with the respective oil.

Table 10 SOP

All combinations according to the invention have extremely low dust number values. The sole use of amorphous silicas, such as Sipernat 22 S or Aerosil 200 F, does not lead to a reduction in the number of dusts.

Table 11 shows the dust behavior of granules obtained by various treatment methods (mixing methods) of SOP broken granules with rapeseed oil and Sipernat® 22 S in a weight ratio of 11: 1 after storage for 1 or 3 weeks. The quantities of oil and silica used per ton of basic granulate are given. For comparison, the basic granulate was examined in an untreated form and in a form treated only with rapeseed oil.

Table 11 SOP

As you can see, the different mixing methods have no effect on the dust-binding effect. Table 12 shows the dust behavior of granules obtained by treating SOP broken granules with rapeseed oil / palm oil mixtures and with various SipernatO silicas in a weight ratio of 11: 1 after storage for 1, 3 or 6 weeks. The amounts of oil and silica used per ton of base granulate are given. For comparison, the basic granulate was examined in its untreated form.

Table 12 SOP Table 13 shows the dust behavior of granules obtained by treating SOP broken granules with rapeseed oil and with Sipernat® 22 S in different weight ratios after storage for 1 or 3 weeks. The amounts of oil and silica used per ton of base granulate are given. For comparison, the basic granulate was examined in an untreated form and in a form treated only with rapeseed oil.

Table 13 SOP

* Slight sticking to the vessel wall observed when shaken * Granulate sticks strongly and is no longer manageable

Table 14 shows the dust behavior of granules obtained by treating potassium sulphate (SOP) broken granules with rapeseed oil and with Aerosil® 200 F in various weight ratios after storage for 1 or 3 weeks. The pro The amount of oil and silica used in the ton of basic granulate is given. For comparison, the basic granulate was examined in an untreated form and in a form treated only with rapeseed oil. Table 14 SOP

^# ^Slight sticking to the vessel wall observed when shaking ## Granulate sticks strongly and is no longer manageable

Investigations with conventional dust-binding 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)

The temperature of the basic granulate (= untreated MOP granulate) was 60 ° C. during the granulate treatment.

Table 15 shows the dust behavior of granules obtained by treating MOP broken granules with rapeseed oil and with Sipernat® 22 S or Aerosil® 200 F in a weight ratio of approx. 11: 1, after storage for 1 or 3 weeks (exposure when determining the value after 3 weeks of storage for 15 minutes instead of 5 minutes). The amounts of oil and silica used per ton of base granulate are given. For comparison, the basic granulate was examined in an untreated form and in a form treated only with rapeseed oil.

Table 15 MOP * 15 minutes instead of 5 minutes.

3.3) Granules based on grain potash (broken granules).

The temperature of the basic granulate (= untreated grain potassium granulate) was 50 ° C. during the granulate treatment (see FIG. 2)).

Table 16 shows the dust behavior of granules obtained by treating granulated potash broken granules with rapeseed oil and with Sipernat® 22 S or Aerosil® 200 F in a weight ratio of approx. 11: 1, after storage for 1 or 3 weeks. The amounts of oil and silica used per ton of base granulate are given. For comparison, the basic granulate was examined in an untreated form and in a form treated only with rapeseed oil. Table 16 Korn-Kali

3.4) Patentkali granulate (roll granulate)

The temperature of the basic granulate (= untreated Patentkali granulate) was 25 ° C. during the granulate treatment.

Table 17 shows the dust behavior of granules obtained by treating Patentkali granules with rapeseed oil and with Sipernat® 22 S in a weight ratio of 9: 1 after storage for 1 or 3 weeks. The quantities of oil and silica used per ton of basic granulate are given. For comparison, the basic granulate was examined in its untreated form.

Table 17 Patentkali granules 3.5) NPK granules

The temperature of the basic granulate (= untreated NPK granulate) was 20 ° C. during the granulate treatment.

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 storage for 1 or 3 weeks. The amounts of oil and silica used per ton of base granulate are given. For comparison, the basic granulate was examined in an untreated form and in a form treated only with rapeseed oil.

Table 18 NPK granules 3.6) SOP granules (broken granules) - various methods of treatment

The temperature of the basic granulate (= untreated SOP granulate) was 20 ° C. during the granulate treatment. Table 19 shows the dust behavior of granules obtained by various treatment methods (joint or separate addition of silica and oil) of SOP broken granules with RBD palm olein and Sipernat® 22 S in a weight ratio of 11: 1, according to 1 and 3, respectively -weekly storage. The amounts of oil and silica used per ton of base granulate are given. Table 19 SOP

Claims

1. A method for reducing the dust generation of granules based on inorganic salts or urea, in particular fertilizer granules, comprising treating the granules with an amount of a combination which reduces the dust formation of the granules, comprising: a) at least one fatty acid triglyceride that is liquid at 20 ° C or at least a mixture of fatty acid triglycerides which is liquid at 20 ° C. as component A; b) at least one amorphous, hydrophilic silica as component B, the mass ratio of component A to component B in the combination being in the range from 40: 1 to 3: 1.

2. The method according to claim 1, wherein component A is selected from vegetable oils, in particular vegetable oils with an iodine number according to Wijs in the range of

20 to 160, determined according to DIN 53241-1: 1995-05, and mixtures of vegetable oils, at least one of the vegetable oils contained in the mixture having this iodine number.

3. The method of claim 1 or 2, wherein component A at 20 ° C and one

Shear rate of 1 s ^{1 has} a dynamic viscosity, determined according to DIN 53019-1: 2008-09, in the range from 20 to 200 mPas.

4. The method according to any one of the preceding claims, wherein 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 mixtures of at least one of the aforementioned vegetable oils with palm oil or coconut oil; and where component A is in particular selected from rapeseed oil, sunflower oil, soybean oil, palm olein, mixtures of these and also mixtures of at least one of the aforementioned vegetable oils with palm oil.

5. The method according to any one of the preceding claims, wherein component B has a specific surface, determined by nitrogen adsorption according to the BET method according to DIN ISO 9277: 2014-01 at 77.3 K, of at least 50 m ² / g, in particular in the range of 80 to 600 m ² / g.

6. The method according to any one of the preceding claims, wherein component B is selected from pyrogenic silica, precipitated silica and mixtures thereof.

7. The method according to any one of the preceding claims, wherein the combination to at least 80 wt .-%, preferably at least 85 wt .-%, in particular at least 90 wt .-%, especially at least 95 wt .-%, based on the Total weight of the combination that consists of components A and B.

8. The method according to any one of the preceding claims, wherein 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-mentioned salts, based on urea or based on a mixture of at least one of the above-mentioned salts or mixed salts with urea; wherein the granules are selected in particular from MOP, SOP, Kornkali-, Patentkali-, Kieserite, ammonium sulfate, MAP, DAP, CAS, TSP, NPK, polyhalite and urea granules and granules that contain at least two of these components.

9. The method according to any one of the preceding claims, wherein components A and B are used for treating the granules in a mixture or separately, the granules being treated simultaneously with component A and component B when used separately.

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

11. The method of claim 10, wherein the oil composition is shear thinning.

12. The method according to claim 11, wherein the oil composition at 20 ° C and a shear rate of 1 s ^{1 has} a dynamic viscosity of at least 500 mPas and at 20 ° C and a shear rate of 300 s ^{1 has} a dynamic viscosity that is at least 200 mPas is below the dynamic viscosity of the oil composition at 20 ° C. and a shear rate of 1 s ¹ , the viscosity values being determined in accordance with DIN 53019-1: 2008-09.

13. The method according to any one of claims 1 to 8, wherein components A and B for treating the granules are used separately and one after the other, the time interval between the treatment with component A and the treatment with component B at most 2 minutes, preferably at most 1 minute, in particular is a maximum of 30 seconds.

14. The method according to any one of the preceding claims, wherein the combination of 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, in particular in the range from 27: 1 to 8: 1 and especially in the range from 25: 1 to 9: 1 .

15. The method according to any one of the preceding claims, wherein the combination is used in an amount of 1 to 10 kg per ton of granules, in particular from 2 to 7 kg per ton of granules.

16. Use of a combination comprising a) at least one fatty acid triglyceride which is liquid at 20 ° C. or at least one mixture of fatty acid triglycerides which is liquid at 20 ° C. as component A; b) at least one amorphous silica as component B, the mass ratio of component A to component B being in the range from 40: 1 to 3: 1 in the combination, as a dust binder for granules based on inorganic salts or for urea granules, in particular for fertilizer granules.

17. Use according to claim 16, wherein the combination has at least one of the features of claims 1 to 14.

18. An oil composition containing a) 75 to 97.6% by weight, based on the total weight of the oil composition, of a fatty acid triglyceride which is liquid at 20 ° C. or at least one mixture of fatty acid triglycerides which is liquid at 20 ° C., as a component

A, where component A at 20 ° C. and a shear rate of 1 s ^{1 has} a dynamic viscosity, determined according to DIN 53019-1: 2008-09, in the range from 20 to 200 mPas; b) 2.4 to 25% by weight, based on the total weight of the oil composition, of at least one amorphous, hydrophilic silica as component B, component B in an amount of at least 6.5% by weight, based on the total weight the oil composition which is contained in the oil composition if component B is fumed silica.

19. Oil composition according to claim 18, wherein component A has at least one of the features of claims 2 or 4.

20. Oil composition according to one of claims 18 or 19, wherein component B has at least one of the features of claims 5 or 6.

21. Oil composition according to one of claims 18 to 20, containing c) 83.3 to 97.6% by weight, preferably 87.5 to 96.8% by weight, in particular 88.9 to 96.4% by weight %, especially 88.9 to 96.2% by weight, based on the total weight of the oil composition, of component A; and d) 2.4 to 16.7% by weight, preferably 3.2 to 12.5% by weight, in particular 3.6 to 11.1% by weight, especially 3.8 to 11.1% by weight .-%, based on the total weight of the oil composition, of component B.

22. Oil composition according to one 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 , particularly preferably in the range from 30: 1 to 7: 1, in particular in the range from 27: 1 to 8: 1 and especially in the range from 25: 1 to 9: 1.

23. An oil composition according to any one of claims 18 to 22, wherein the oil composition is shear thinning.

24. Granules, obtainable by the process according to any one of claims 1 to 15.