阅读说明：本技术 生产金属螯合物的节能的无溶剂方法 (Energy-saving solvent-free method for producing metal chelates ) 是由 D·E·考夫曼 J·C·纳米斯洛 R·弗洛雷斯库 B·瓦夫日涅克 于 2018-01-08 设计创作，主要内容包括：本发明涉及制备氨基酸-金属螯合物和/或羟基羧酸-金属螯合物的方法,其中对至少一种金属氧化物、金属氢氧化物、金属碳酸盐或金属草酸盐和固态有机酸的无溶剂的混合物施加强的机械应力。根据本发明,这是通过将反应物以颗粒形式引入没有研磨介质的流化床对置喷射研磨机的流体射流中进行的,其中在流体射流的射流区域中形成的反应空间中通过颗粒碰撞过程引起至少一种反应物的机械活化,并且引发形成金属螯合物的固态反应。这一新型方法可以非常节能的方式以高的比产率运行。获得的产物具有在小的一位数微米范围内的致密颗粒,具有较窄的粒径分布和大的表面积。所述产物均匀且非常纯净。避免了有机螯合物配体,特别是氨基酸的热应力或分解,也避免了来自研磨机和研磨介质的磨损材料的污染。(The invention relates to a method for producing amino acid-metal chelates and/or hydroxycarboxylic acid-metal chelates, wherein at least one metal oxide, metal hydroxide, metal carbonate or metal oxalate and a solvent-free mixture of a solid organic acid are subjected to an intensive mechanical stress. According to the invention, this is carried out by introducing the reactants in the form of particles into the fluid jet of a fluidized-bed opposed-jet mill without grinding media, wherein mechanical activation of at least one of the reactants is brought about by the process of particle collision in a reaction space formed in the region of the jet of the fluid jet and a solid-state reaction is brought about in which metal chelates are formed. This novel process can be operated in a very energy-efficient manner with high specific yields. The product obtained has dense particles in the small one-digit micrometer range, with a narrow particle size distribution and a large surface area. The product was homogeneous and very pure. Thermal stress or decomposition of the organic chelate ligand, particularly the amino acid, is avoided, as is contamination of the abrasive material from the mill and the grinding media.)

1. Process for the preparation of amino acid-metal chelates or hydroxycarboxylic acid-metal chelates in which a solvent-free mixture of at least one metal compound selected from the group consisting of metal oxides, metal hydroxides and metal salts and at least one solid organic acid comprising at least one chelating acid selected from the group consisting of α -amino acid and β -amino acid and hydroxycarboxylic acid is subjected to an intensive mechanical stress, characterized in that the reactant metal compound and the organic acid are introduced in the form of particles into the fluid jet of a fluidized-bed opposed-jet mill (10) without grinding medium and in that the mechanical activation of at least one reactant is brought about by the particle collision process in a reaction space (5) formed in the region of the jet of the fluid jet and a solid-state reaction is brought about in which the metal chelate is formed.

2. A method according to claim 1, characterized in that in a fluidized bed opposed jet mill, in the fluid flow section, in the area of intersection of the injection directions of at least two fluid nozzles (4), a fluidized bed is formed as a reaction space (5) together with the introduced particulate reactant.

3. Method according to claim 1 or 2, characterized in that the fluidized bed opposed jet mill (10) is operated with a flow rate of about 300 to 1000m/s and a grinding gas pressure of about 5 to 10bar, preferably about 7 to 8 bar.

4. A method according to any one of claims 1 to 3, characterized in that the reactants are conveyed into the grinding chamber (1) by means of a conveying device and arrive in a free-falling manner in a reaction space (5) inside the grinding chamber (1).

5. Method according to one of claims 1 to 4, characterized in that the fluid is a gas, preferably selected from the group consisting of: air, nitrogen, argon, carbon dioxide and steam, in each case individually or as a mixture.

6. Process according to one of claims 1 to 5, characterized in that the metal compound is an inorganic metal oxide, metal hydroxide or metal mixed oxide, or an inorganic or organic metal salt, preferably a metal carbonate or metal oxalate.

7. The method according to one of claims 1 to 6, characterized in that the metal compound contains at least one metal selected from the group consisting of zinc (Zn), copper (Cu), manganese (Mn), selenium (Se), iron (Fe), calcium (Ca), magnesium (Mg), nickel (Ni), cobalt (Co), vanadium (V), chromium (Cr), and molybdenum (Mo), or a mixture of the metal compounds is used.

8. A metal chelate composition comprising at least one metal chelating compound, wherein the metal chelating compound has a polyvalent metal cation and at least one chelate ligand comprising at least one chelating acid selected from the group consisting of α -amino acids and β -amino acids and hydroxycarboxylic acids, characterized in that the compound is present in the form of particles having an average particle size in the range of one-digit microns.

9. The metal chelate composition according to claim 8, wherein the metal chelating compound is present in the form of particles in which 90% of the particles have a diameter of not more than 15 μm and 50% have a diameter of not more than 5 μm.

10. The metal chelate composition according to claim 8 or 9, wherein the metal chelating compound is present in the form of particles in which 99.9% have a diameter of not more than 25 μm.

11. The metal chelate composition according to one of claims 8 to 10, characterized in that the metal chelate compound is free of abrasive material from the mill and the grinding media.

12. Metal chelate composition according to one of claims 8 to 11, characterized in that in the at least one metal chelating compound the stoichiometric ratio of chelating acid to metal compound is between 0.5:1(mol/mol) and 4:1 (mol/mol).

13. Metal chelate composition according to one of claims 8 to 12, characterized in that the metal of said one or more metal chelating compounds is selected from zinc (Zn), copper (Cu), manganese (Mn), selenium (Se), iron (Fe), calcium (Ca), magnesium (Mg), nickel (Ni), cobalt (Co), vanadium (V), chromium (Cr) and molybdenum (Mo).

14. Metal chelate composition according to one of claims 8 to 13, characterized in that the metal chelating compound or at least one metal chelating compound present is a 2:1 amino acid-metal chelating compound of zinc or copper or a 3:1 amino acid-metal chelating compound of iron or manganese.

15. Metal chelate composition according to one of claims 8 to 14, characterized in that it comprises or consists of at least one of the following metal chelate compounds: zinc bisglycinate, zinc bismethionine, copper bisglycinate, copper bislysine, copper bismethionate, (selenium methionine, selenium cysteine), iron bisglycinate, iron trisglycinate, iron bislysine, iron trislycinate, iron trisglycinate, manganese bislycinate, manganese trislycinate, manganese bismethinate, and manganese trismethinate.

16. Use of a metal chelate composition according to one of claims 8 to 14 as or in feed additives, food products, food supplements, food additives, pharmaceuticals, preservatives, in pharmaceutical compositions, as or in fermentation additives, fertilizer additives, seed treatment agents, crop protection agents, catalysts for chemical reactions, or as or in plating additives.

17. Composition containing the process product of one of the claims 1 to 7 or the metal chelate composition of one of the claims 8 to 14 in the form of a feed additive, a food supplement, a food additive, a pharmaceutical, a preservative, a pharmaceutical composition, a fermentation additive, a fertilizer additive, a seed treatment, a crop protection agent, a catalyst for chemical reactions or a plating additive.

Technical Field

The present invention relates to the efficient preparation of metal chelates, in particular amino acid-metal chelates and hydroxycarboxylic acid-metal chelates, wherein a dry, i.e. solvent-free, mixture of at least one metal compound selected from the group consisting of metal oxides, metal hydroxides and metal salts and at least one solid organic acid comprising at least one chelating acid selected from the group consisting of α -amino acid and β -amino acid and hydroxycarboxylic acid is subjected to an intensive mechanical stress to prepare said chelate, the invention also relates to the corresponding metal chelate compositions obtainable by means of this process, the use thereof and further compositions comprising the process product according to the invention or the metal chelate compositions.

Background

Chelates or synonymous chelate complexes are coordination compounds in which at least one polydentate ligand, hereinafter referred to as chelate ligand or "chelator", occupies at least two coordination or bonding positions on the central atom. In a chelate complex, one or more chelating agents may be present per central atom. The central atom is a positively charged metal ion of a metal, such as zinc (Zn), copper (Cu), manganese (Mn), selenium (Se), iron (Fe), calcium (Ca), magnesium (Mg), nickel (Ni), cobalt (Co), vanadium (V), chromium (Cr), and molybdenum (Mo), among others. In chelates, certain metals are in only one valence state (e.g., Zn)²⁺) As cations, while other metals (e.g., those of Cu, Fe, Ni, Co, V, Cr, or Mo) occur in multiple valence states or as oxocations, e.g., molybdenum oxocations in oxidation states + IV, + V, and + VI and typically as vanadium-based VO²⁺Vanadium in its form.

Trace elements and trace element compounds have long been known to be present in small amounts ("traces") in animals, humans or plant organisms and often perform vital functions for life, as can be seen from the fact that their absence leads to the appearance of deficiency or disease symptoms, general weakness and/or reduced reproduction rates. It is therefore of great interest to be able to provide these elements in a suitable administration form.

Using compounds containing other electron-donor groups (-NH)₂Organic acid anion(s), especially amino acid anion(s), as chelate complex of the corresponding metal, and thus also the use of amino acids and/or hydroxycarboxylic acids, in addition to trace elements, are known and customary, which are in any case often administered in the form of supplements, with positive physiological effects in the form of slightly bioavailable complexes (see, for example, KW Ridenour, US 5702718(a), 1997 and the patents cited therein).

However, it is preferred to use naturally occurring amino acids, alanine, arginine (basic), aspartic acid (acidic), cysteine, glutamine, glutamic acid (acidic), glycine, histidine (basic), isoleucine, leucine, lysine (basic), methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine and valine.

Suitable processes for the preparation of said compounds, which are widely used, for example, as additives in human and animal nutrition, are of great interest. The chelating stability should not have an adverse effect on the bioavailability of amino acids or hydroxycarboxylic acids. Many amino acid chelates even increase the bioavailability of the co-administered central cation compared to the salt or oxide of the cation.

Biological reporting (bionics) of specific chelating compounds in human or animal organisms is particularly effective, as demonstrated by scientific research. Amino acid chelates having moderate strength chelated via a nitrogen atom exhibit particularly high bioavailability. As well documented in the literature and known to the person skilled in the art, the bioavailability of metals is generally found to be significantly higher when used in the form of their chelates, compared to when using the corresponding inorganic metal salts.

According to the state of the art, suitable amino acid-metal chelates as organic trace element compounds are produced primarily by wet-chemical methods or mechanical methods which are likewise energy-intensive, in particular with grinding media, in particular in ball mills, operating with low energy efficiency, in the latter case only about 90% of the supplied energy being converted into heat (see EP2489670 a 1). The known wet-chemical methods are burdened in particular by the inevitable energy inefficiency and the correspondingly expensive drying of the material. Furthermore, the product is free of extraneous inorganic anions.

Solvent-free processes are also known in particular from the prior art (Rummel, US 2877253(A), 1959; Ashmead, Pedersen, US 6426424(B1), 2002; Pedersen, Ashmead, US 6518240(B1), 2003). Although solventless processes do not have the above-mentioned disadvantages of having to remove large amounts of solvent (usually water) per se, they require additional energy when forming the product in a mechanical mill containing milling media, especially in a ball mill. The reason for the increased energy consumption is that the grinding media must be moved as additional mass in an eccentric vibratory grinding (EVM) machine, for example in the processes described in d.ramhold, e.g. gock, e.mathies, w.strauch, EP2489670(a1), 2012. When using an eccentric vibrating mill, the energy consumption for driving the counterweight is additional. In addition, in such unevenly running vibration mill systems, higher wear is observed due to high impact stress on the grinding media themselves. Abraded material can then be undesirably found in the product.

Furthermore, the drying of the materials mentioned at the outset also becomes important in the last-named process, since the reaction water formed in this type of reactive grinding has to be removed again with additional energy consumption with heating and/or pressure reduction.

Another disadvantage of the above solid state process for producing metal chelates is that the solid product sometimes has considerable dimensional and structural heterogeneity. Thus, for example, the process described in EP2489670 a1 produces needle-like metal-amino acid chelate structures having an average particle size of 40 to 60 μm, with up to 80% of the particles having a particle size >0 to 100 μm and up to 2% being greater than 500 μm, i.e. a value 10 times greater than the "average particle size" of 50 μm, and therefore having a large number of oversized particles.

The great structural heterogeneity generally increases the difficulty of further processing the obtained metal chelate, for example, classification according to particle size, precise metering and uniform mixing with other substances. The release kinetics of the active compound are also adversely affected by the non-uniformity of the particle size. The extremely large needle-like morphology hinders the flowability and dispersibility of the granular product. The acicular crystals of the complexes are not readily soluble in water and sometimes even insoluble in acids, and may be harmful to health after absorption in humans or animals. Needle-like structures should therefore be avoided.

Disclosure of Invention

It is therefore an object of the present invention to avoid as far as possible the disadvantages of the prior art in terms of production processes and to provide metal chelates having different morphologies. Energy-saving processes with high yields and high selectivities should be provided here. By-products and decomposition products, in particular organic complexing ligands, should be avoided.

This object is achieved by the process according to claim 1 and the particular process products, i.e. the metal chelates produced and the metal chelate compositions according to claim 8, the use according to claim 16 and the compositions according to claim 17. Advantageous embodiments of the invention are indicated in the appended claims.

The starting materials for the process are present in the solid state of aggregation. The particle properties of the starting material may correspond to the usual commercially available forms of fine particles or fine crystals of the material. It is generally not necessary to pre-grind the feedstock. The metal oxides used, such as zinc oxide and copper oxide, may have a particle size of, for example, 150 to 300 μm, and may be used in this form. Solid organic acids are commercially available in particle sizes of about 200 to 500 μm and can likewise be used directly, i.e. in commercially available particle sizes.

For providing the central atom, a metal oxide, a metal hydroxide, including mixed oxides and mixed hydroxides, an inorganic metal salt and an organic metal salt are used. For chelate ligands, i.e. as chelating organic acids, amino acids and/or hydroxycarboxylic acids are used. Other ligands that are not bidentate may be included. The starting materials can be used in premixed form or they can be introduced separately into the fluidized-bed opposed-jet mill used as reactor and mixed in a special apparatus or directly in the milling space of the mill. Metal oxides, metal carbonates and metal oxalates are preferred as metal compounds.

According to the invention, the reactants, i.e. at least the metal compound and the organic acid used, are introduced in particulate form into the fluid jets of a fluidized-bed opposed-jet mill without grinding media. It is important that all reactants are fed to the collision zone in the milling space, in which zone sufficient excitation and activation energy of the reactants can be provided for the desired complex reaction by particle-particle collision in the milling gas jet, especially in the center of the nozzle jets. This occurs during use of the fluid bed opposed jet mill of the present invention, primarily in the same region where "milling" (herein "jet milling") occurs in conventional use, i.e., comminution of solid particles which may otherwise occur herein. The milling space comprises a reaction zone and forms a reaction space for reactive milling or reactive milling to take place therein. The process can be carried out continuously by continuous feeding of the reactants. The fluidized-bed opposed jet mill to be used requires not only much less energy than a mill using grinding media, but also less energy than a conventional jet mill in which an abrasive is introduced into a grinding space together with a grinding gas flow and a rubbing process is performed between the abrasive and a mill wall. Furthermore, the fluidized-bed opposed jet mill is therefore virtually free of wear during operation (this is in contrast to conventional ball mills and conventional jet mills).

In summary, it can be said that the mechanical activation of at least one reactant is caused by particle collision processes within the reaction space formed in the jet region of the fluid jet or jets and initiates a solid-state reaction to form the metal chelate.

The method is based on particle acceleration by means of an abrasive gas flow at high pressure and subsequent collision of these particles, in particular at the focal point of the abrasive gas flow towards each other. The corresponding collisions lead to such a high energy input that the corresponding organic acids and the metal source used react to form chelates.

Here, the oxygen in the metal component will form pure water, which will be discharged with the grinding gas stream at the high gas velocity of the process. Therefore, no additional energy needs to be consumed for this purpose.

With regard to the formation of the product, it is assumed that particle collisions, especially in the center of the gas jet, caused by jet velocities of typically 300 to 1000m/s, lead to lattice defects caused by the point loading. Even at room temperature and 6bar gauge, a grinding gas velocity of 500m/s is achieved. The above lattice defects may be mainly present in the metal compound having a high specific gravity used and may allow a subsequent reaction to form an amino acid-metal chelate. Previous energy-intensive activation is not required, which means further energy savings, for example in the case of corresponding reactive grinding processes in eccentric vibratory mills (as described, for example, in d.ramhold, e.g. gock, e.mathies, w.strauch, EP2489670(a1), 2012). The high values of the grinding gas velocity shown have corresponding advantages for the degree of particle-particle collisions in the grinding space of the fluidized-bed opposed-jet mill, which is achieved in particular when the grinding gas is a naturally-obtained hot gas from a compressor, and is not cooled by energy consumption (which is otherwise customary practice), but is used directly as hot gas.

The metal chelate may be a "pure" chelate prepared from a metal compound and an amino or hydroxycarboxylic acid, or a mixed product in the case of using metal oxides of metals and/or different acids in mixture.

The product was collected in a product filter installed downstream of the fluidized bed opposed jet mill.

In this way, the disadvantages of the methods known from the prior art, which are disadvantageous from the point of view of process engineering and/or energy, can be avoided. The invention is based on the recognition that: fluidized bed opposed jet mills, originally designed for very fine grinding, allow such high energy inputs into the mill stock that, with the proper choice of raw materials and operating conditions, mechanochemical reactions occur only by the particles of the material colliding with one another without the involvement of grinding media or other frictional surfaces.

In contrast, it is known from the literature to date that such solid-state reactions are caused by collisions with grinding media in ball mills (centrifugal mills, eccentric vibratory mills, see for example d.ramhols, e.g. gock, e.mathies, w.strauch, EP2489670(a1), 2012). This mechanochemistryThe mechanism of reaction is generally thought of as the large point loading associated with localized high temperatures (see, e.g., b.v. boldyev, k.meyer,

VEB Verlag f ü rGrundstoffindustrie, Leipzig,1973, D.Margetic, V.Strukil, Mechanochemical organic Synthesis, Elsevier Science Publishing Co.Inc., 2016. temperature-sensitive organic ligands, i.e., here amino acids and/or hydroxycarboxylic acids, can undergo undesirable degradation reactions in the process.

In the case of the present invention, on the other hand, no grinding media are present. In this way, a large amount of energy can be saved, since no additional mass has to be moved. In addition, in a fluidized-bed opposed-jet mill, the resource-saving method according to the invention has the advantage that the end product is free of correspondingly worn metal, due to the absence of (steel) grinding media as described above. The organic ligands are likewise only subjected to mild conditions. Since no heat input occurs in the process, the tendency of secondary and degradation reactions in the ligand is greatly reduced, i.e. not thermal reactions, nor the result of strong mechanical activation by means of large amounts of grinding media.

Since the process is carried out in the absence of solvent, there is no associated contamination of the solvent either in the production process or in the product. No thermal stress of the product due to thermal drying occurs. The use of industrially troublesome salt solutions and the disposal of large amounts of residual salts as by-products are likewise dispensed with. Due to the synthesis, the process product is preferably free of sulfur and sulfate salts, and generally free of salt anions not required in the process.

According to the invention, a fluidized bed gas jet mill is used, in which particle collisions occur in the center of a plurality of fluid nozzles directed towards one another. Here, the opposed jet arrangement is any arrangement that employs the principle of opposed jet, regardless of the particular angle between the fluid nozzles or the abrasive gas nozzles. The fluid nozzles or milling gas nozzles can preferably be arranged at an angle of 180 ° to 60 ° relative to one another, while the nozzles from the "opposed jets" have to intersect to form a collision space, which is used as a reaction space according to the invention.

In a preferred embodiment, in the fluid stream section, in the region of the intersection of the injection directions of at least two fluid nozzles, a fluidized bed is formed together with the introduced particulate reactants, wherein the fluidized bed provides a chelate-forming reaction space. It is presently believed that two to six fluid nozzles, more preferably two to four fluid nozzles or abrasive gas nozzles, operating in an opposed-spray mode are preferred.

In a preferred embodiment, the fluidized-bed opposed jet mill is operated at a flow rate of about 100 to 1000m/s, preferably 250 to 1000m/s, more preferably 300 to 1000m/s, in particular 300 to 700m/s, and the grinding gas pressure is about 5 to 10bar, preferably about 7 to 8 bar.

Instead of the conventional pure millbase, the reactants provided at the inlet of the mill or fed to the mill, i.e. the solid particulate metal hydroxide, metal carbonate or metal oxalate and the solid amino-and/or hydroxycarboxylic acid, are fed as "reaction material". Preferably, this is usually done from one or more storage containers (tanks) or from sacks in batches by means of a separate feeding device, such as a shaft or a feeding conduit with or without additional conveying means.

The use of a fluidized bed opposed jet mill means that the reaction material is added directly to the milling space; in this way, the gas introduced through the nozzles is itself free of particles of raw material, which otherwise would cause abrasion and wear as in the case of conventional jet mills, as a result of the material being transported through the nozzles, in particular in conventional mills (in particular ball mills) using grinding media.

In a particularly preferred embodiment, the reactants are conveyed into the grinding chamber by means of a conveying device and arrive in a free-falling manner in the reaction space inside the grinding chamber. The conveying device preferably has at least one conveying screw.

The particle size of the final product can be set by selecting the operating conditions of the fluidized bed opposed jet mill and the classification wheel, which is also usually installed in the medium to small micron range (average diameter is determined in a conventional manner in the art, for example by means of laser scattering) as a standard for very fine milling.

The process product is dense and fine particulate. The dense structure contains little crystal needles and no significant proportion of extra large particles. More than 80% of the particles have an oval or cuboid structure with a ratio of longest particle size to shortest particle size of less than 4: 1. Due to the dense, fine particle structure, a large surface area is present, which has a positive influence, for example, on the scattering or flowability of the product, on dry-mix solubility, on the dispersibility and metering accuracy, and on the pharmaceutical properties of the product, if applicable. Thus, the process product can be incorporated more easily into the mixture and briquettes and distributed more evenly therein.

The product is obtained in a particularly finely divided form with a narrow particle size distribution. The latter may for example be represented by the ratio D of the values of D₉₉、D₉₀、D₅₀、(D₁₀) And is seen. The D value represents the percentage of particles smaller than the diameter given by the corresponding D value. The percentages are given by indices, i.e. D₉₀By … is meant "90% of the particles (by volume) have a diameter of less than …". The relevant data is obtained by laser light scattering.

In contrast to the known energy-intensive solid-state processes using grinding media, particularly dense and uniform particle sizes are obtained. Thus, for example, the mean particle diameter of the acicular chelate particles described in patent application EP 2389670a1 and in the electron micrographs is from 40 to 60 μm, with up to 80% of the particles being from 0 to 100 μm, which corresponds to a D80 value of 100 μm. In contrast, in the case of the present invention, a very steep, more uniform and more defined particle size distribution is obtained, and the average particle size of the particles as a whole is typically 1.5 to 3.5 μm, more than an order of magnitude smaller (40 to 60 μm in the case of the ESM process, see above). This is advantageous for further processing steps, especially when mixing defined amounts of chelate with defined amounts of other substances, since a uniform particle size distribution makes processing by machine considerably easier. The risk of lump formation is reduced and the mechanical components of the classification, measurement, metering and dispensing apparatus can be better matched to a particular chelate crystal size. Specific post-treatment steps may be omitted, such as grinding the resulting chelate crystals to obtain a uniform, sufficiently small particle size.

Typically, a very small amount of metal-acid chelate is mixed with, for example, 1000 times its amount of other materials, for example, in animal feed or when used as a catalyst. In order to be able to add defined amounts of chelating agents and mix them homogeneously with other materials, it is very advantageous that the chelating agents have a uniform, well-defined particle size.

The product of the process according to the invention is obtained in the form of compact crystals, i.e. practically without needles and without a significant proportion of very large particles. When administered to humans or animals, the detrimental effects on health no longer occur in the case of the needle-like chelate crystals obtained according to the prior art.

It must be emphasized that the reactive grinding according to the invention in a fluidized-bed opposed-jet mill is carried out completely spontaneously and that in this way the entire energy for the product formation, including the necessary activation energy, is provided only by the gas jet. The temperature increase does not have to be carried out from the outside, nor does an uncontrolled temperature increase occur in the materials used, which could damage the product, as in the case of the classical reactive grinding operations in which the process is carried out, mainly by impact and friction of the grinding media themselves. Furthermore, the process of the present invention has the advantage that the fluidized bed opposed jet mill allows the process to be operated continuously, thereby increasing the throughput at a lower specific energy consumption, compared to the reactive milling in conventional ball mills, typically eccentric vibratory mills.

A comparative calculation of the respective specific energy consumption in an eccentric vibratory mill (single module, ESM 504, from Siebtechnik GmbH, M ü lheiman derRuhr) and a fluidized bed opposed jet mill (CGS 71, from Erich NETZSCH GmbH & Co. holding KG, Selb) is given in the following sections:

eccentric vibratory mill ESM 504:

power (dry + mixer): 27.5KW

And (3) outputting: 40kg/h

Grinding medium: cylpeps 32mm X32 mm (Steel)

Specific energy consumption [ KWh/ton ]: 27.5KW/40kg/h 1000kg 688KWh/t

Fluidized bed opposed jet mill CGS 71:

air flow: 1920m³H (8 bar, 20 ℃ C.; ISO 1217)

The classification turns to power: 15KW

Compressor power (1956 m)³H, main drive + split fan (sep.fan)): 206KW

And (3) outputting: 500kg/h

Specific energy consumption [ KWh/ton ]: 221KW/500kg/h 1000kg 442KWh/t

In contrast to fluidized-bed opposed-jet mills, in the case of eccentric vibrating mills, it is only possible to operate batchwise.

Therefore, in the case of using the fluidized-bed opposed jet mill according to the present invention, the energy consumption per ton of product is more than one third lower than that of the conventional product plant based on the eccentric vibration mill for amino acid-metal chelate. Furthermore, the process is characterized by the omission of slightly catalytically active agents (e.g. iron ions) and (in terms of energy) the avoidance of complicated prior or subsequent treatment steps (e.g. spray drying).

Thus, the present invention now provides an efficient solvent-free process for preparing complexes of chelate-forming metals, preferably zinc, copper, manganese, selenium, iron, calcium, magnesium, nickel, cobalt, vanadium, chromium or molybdenum, preferably zinc, copper and selenium, with solid organic acids, preferably naturally occurring amino acids, preferably glycine, methionine, lysine and/or cysteine, and alanine, arginine, aspartic acid, glutamine, glutamic acid, histidine, isoleucine, leucine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine and valine. In general, all chelate-forming amino acids and/or hydroxycarboxylic acids of synthetic and natural origin are suitable.

The reaction is effected exclusively by mixing a mixture of various metal compounds, preferably in the form of oxides (in particular ZnO, CuO, Fe), with a solid mineral acid, preferably with the participation of at least one amino acid, as described above, and subjecting the mixture to mechanical stress in a fluidized-bed opposed-jet mill₂O₃、Mn₂O₃Or the corresponding oxides of other metals desired for the product being produced), or in the form of the oxalate or carbonate of the selected metal of the compound being produced.

The conversion of the reaction during the mechanochemical solid-state reaction depends on the operating conditions in the fluidized-bed opposed-jet mill relevant to the present invention (i.e. on the milling gas flow and milling gas pressure, the type and temperature of the milling gas or fluid, preferably air, optionally also nitrogen, argon, carbon dioxide or steam, and on the rotational speed of the classifier and the amount of raw materials added). The entry rate of the incoming gas, particularly the geometry, size and arrangement of the nozzles, and the degree of accumulation of the reacting abrasive in the reaction chamber are also critical to the occurrence of the solid state reaction.

Suitable fluidized bed opposed jet mills are, in particular, the industry standard for pollution-free comminution and have been known in principle for a long time (see, for example, P.M. Rockwell, A.J. Gitter, am. center. Soc. Bull.1965,44, 497-499). Since about 20 years ago, much research has been carried out again on the development and optimization of such fluidized bed opposed jet mills (see, for example, P.B.Rajendran Nai, S.S.Narayanan, From World Congress on particle technology 3, Brighton, UK, July 6-9,1998(1998), 2583-. Fine or very fine grinding is often attempted down to the 1 micron range, taking Drug use as a major consideration in optimizing parameters (see, e.g., p.w.s.heng, l.w.chan, c.c.lee, s.t.p.pharma Sciences 2000,10, 445-.

For example, even very hard materials, including for example silicon carbide or alumina (Y.Wang, F.Peng, part.Sci.Technol2010, 28, 566-.

The actual process of utilizing chemical reactions, which has not previously been utilized in the manner of the present invention, is characterized by the breaking and subsequent reformation of chemical bonds and, therefore, reactive grinding under the operating conditions of a fluidized bed opposed jet mill. Examples of surface modification of ZnO nanoparticles can be found in the following documents: x.su, z.cao, q.li, z.zhang, j.adv.microscopi res, 2014,9,54-57 and x.su, s.xu, t.cai, guangzhou hua 2012,40, 101-.

The invention results in process products with novel, hitherto unattainable, new product properties and includes products of uniform structure which are novel in this form and have a very narrow particle size distribution. The fine-grained nature of the product is also worth particular emphasis.

The object of the invention is therefore also achieved by a metal chelate composition, wherein the metal chelate composition contains at least one metal chelate compound having a polyvalent metal cation and at least one chelate ligand, wherein the chelate ligand comprises at least one chelate acid selected from the group consisting of α -amino acids and β -amino acids and hydroxycarboxylic acids, wherein the compound is present in the form of particles having a particle size in the range of one-digit microns, i.e. an average particle size of ≤ 5 μm (D)₅₀1-5 μm) as described above in the present invention.

The metal chelate composition contains or consists of at least one metal chelate compound.

The invention includes the metal chelating compounds obtained directly as a product of the process of the invention, i.e. the pure metal chelating compounds formed on the basis of the stoichiometric composition of the starting materials, and also compositions which comprise these metal chelating compounds in addition to other materials which may be the remaining starting materials in the first place, or additives or other materials which supplement the composition, which are introduced into the mill in the process.

The metal chelate compound is a coordination compound (also referred to as complexing compound, complex) as described above having at least one metal cation which is polyvalent, i.e. at least divalent, and at least one chelate ligand, wherein the chelate ligand comprises at least one organic, chelated, i.e. at least bidentate in respect of complexation, acid selected from the group consisting of α -amino acid and β -amino acid and hydroxycarboxylic acid.

According to the present invention, the presence of other ligands in the metal chelate compound than those specifically mentioned and claimed, i.e. other bidentate or monodentate ligands and/or monovalent or polyvalent anions, is not excluded. This may be desirable, for example, in order to broaden the scope of use of the metal chelate compositions of the present invention.

In the chelate complex, in addition to at least one amino acid or hydroxycarboxylic acid as a ligand, it is also preferable that the complex acid to be incorporated is nicotinic acid. The related products are amino acid-nicotinic acid-metal chelates, e.g., copper-nicotinic acid-glycinate or selenium-nicotinic acid-methionine.

The metal chelate compounds and metal chelate compositions according to the present invention are dry, solid, particulate materials or products having a characteristic structure and size distribution.

In a particularly characteristic embodiment, the metal chelate compound is present in the form of particles in which 90% of the average particle diameter (individual particle diameter) is not more than 15 μm and 50% of the average particle diameter (individual particle diameter) is not more than 5 μm (D)₉₀≤15μm；D₅₀Less than or equal to 5 mu m). For these examples, the average particle size (average of all particles in the sample) is 1 μm to 5 μm.

Typical D of Individual samples₅₀The value is 1.5 to 4.5. mu.m.

Typical D of Individual samples₉₀The value was 4 to 6 μm. D₉₀Preferably less than or equal to 15 μm, and D₉₀More preferably ≦ 7 μm.

Typical D of Individual samples₉₉The value is 8 to 15 μm. D₉₉Preferably less than or equal to 20 μm, D₉₉More preferably ≦ 15 μm.

Based on these values there are no oversized particles, since the size of the largest particles according to the invention is still below 25 μm (D)_99.9Less than or equal to 25 mu m, equal to or<Sieving exclusion limit of 25 μm).

It can be seen from figure 2c that the particle size distribution of the product of the process according to the invention is also much narrower than previously obtainable. This clearly distinguishes the products of the invention from known products prepared by wet chemistry or dry chemistry.

Due to the fine particle nature and relatively uniform particle size, the metal chelate compound or metal chelate composition of the present invention obtained by the present process can be easily metered, easily dispersed and free-flowing, and easily dry-blended and dispersed. The fine microstructure can also have a positive effect on the storability of the product.

The metal chelate compounds according to the invention are free of abrasive material from the grinding mill and grinding media.

The metal chelate compound is preferably completely free of chloride and/or sulfate ions as ligands.

The metal chelate composition is also preferably characterized in that the stoichiometric ratio (molar ratio) of the chelating acid to the metal compound is from 0.5:1 to 4:1, based on the chelate mixture of each individual chelating compound. In particular embodiments, the or at least one metal chelating compound present in the metal chelate compositions of the present invention is a 2:1 amino acid-metal chelating compound, preferably zinc or copper, or a 3:1 amino acid-metal chelating compound, preferably iron or manganese.

As the analytical results reported below clearly show, the process of the invention makes it possible to obtain well-defined, chemically pure chelates, as the selected metal-amino acid 1:2 chelate, as examined by means of IR spectroscopy. Since amino acid chelates can be stored particularly easily or their constituents have particularly high bioavailability, high conversion and chemical purity of the product is a very important quality advantage of the product according to the invention. Furthermore, the absence of contamination by abraded metal also significantly improves the quality, in particular because no grinding media are used and there is no particular morphology of the product.

In general, a variety of central atoms may be selected. In a preferred embodiment, the metal of the metal chelate compound or of at least one metal chelate compound is selected from the group consisting of zinc (Zn), copper (Cu), manganese (Mn), selenium (Se), iron (Fe), calcium (Ca), magnesium (Mg), nickel (Ni), cobalt (Co), vanadium (V), chromium (Cr) and molybdenum (Mo).

In a preferred embodiment, the chelating organic acid of the metal chelate composition of the present invention is selected from the group consisting of α -hydroxycarboxylic acids, β -hydroxycarboxylic acids, natural amino acids, essential amino acids, and synthetic amino acids.

The metal chelates of the invention include in particular the following substance types and substances:

zinc bisglycinate, zinc bismethionate, copper bisglycinate, copper bislysinate, copper bismethionate (Kupferbismethionate), (selenium bismethionate, selenium cysteine), iron bisglycinate, iron trisglycinate, iron bislysinate, iron trislycinate, manganese bisglycinate, manganese bislycinate, manganese trisiliconate, and manganese trisiliconate.

The metal chelates of the invention can be used in a conventional manner. In particular, the following uses will be mentioned herein: in feed additives, in food products, as and in nutritional supplements, as or in nutritional additives, as or in pharmaceuticals, as or in preservatives, in pharmaceutical compositions, as or in fermentation additives, as fertilizer additives, in seed treatment agents, in crop protection agents, as catalysts for chemical reactions or in plating additives. Thus, the present invention also includes compositions for the above uses which have been prepared or formulated for such uses and which contain the process product of the process of the present invention, i.e., the metal chelate compositions as described in more detail above.

Working examples

The effect of the invention on the mechanochemical stress of metal oxides, metal carbonates or metal oxalates and in each case organic acids, preferably amino acids, in a fluidized-bed opposed-jet mill is illustrated below by means of several examples. The reactive grinding of the process according to the invention is carried out here, for example, on a 2 to 22 kg scale. This is not meant to be limiting. In principle, it is also possible to use a relatively large fluidized-bed opposed-jet mill as a reactor for chelate preparation by changing the size, either by feeding in relatively large amounts or continuously. Larger fluidized bed opposed jet mills for jet milling have been commercially available. Working examples reported are fluidized bed opposed jet mills from the manufacturer Hosokawa Alpine, under the names AFG 100 and AFG 400 from Augsburg, or under the name CGS 10 from the manufacturer Netzsch, Hanau.

Working example 1:

1.501kg of glycine (20.0mol) and 0.814kg of zinc oxide (10.0mol) were mixed in a fluidized-bed opposed-jet mill at 50 to 80m³The mixture was milled for 45 minutes under an air flow at a milling gas pressure of 7.0bar and a classifier speed of 18000s^-1. IR spectrum analysis (FIG. 4) of the final product showed that the amino acids (A), (B), (C>95%) was almost completely converted into the corresponding zinc glycinate (synonym according to Chemical Abstracts Society (CAS): a) bis (glycine-N, O) zinc, b) bis (zinc glycinate) zinc, c) zinc glycinate, d) glycine, zinc complex, e) zinc bisglycinate, f) zinc glycinate, g) zinc (II) glycinate, h) zinc bis (glycinate). The IR spectrum corresponds to the IR spectrum of the commercial reference, CAS: 14281-83-5.

Working example 2:

1.940kg of methionine(13.0mol) and 0.529kg of zinc oxide (6.5mol) in a fluidized-bed opposed-jet mill at 50 to 80m³The mixture was milled for 45 minutes under an air flow at a milling gas pressure of 7.0bar and a classifier speed of 18000s^-1. IR spectrum analysis (FIG. 5) of the final product showed that the amino acids (A), (B), (C>95%) was almost completely converted into the corresponding zinc methionine (chemical abstracts number, CAS: 40816-51-1).

Working example 3:

1.900kg of lysine (13.0mol) and 0.529kg of zinc oxide (6.5mol) were mixed in a fluidized-bed opposed-jet mill at 50 to 80m³The mixture was milled for 45 minutes under an air flow at a milling gas pressure of 7.0bar and a classifier speed of 18000s^-1. Also, purity was obtained>95% of the final product zinc lysine.

Working example 4:

1.576kg of glycine (21.0mol) and 0.835kg of copper oxide (10.5mol) were mixed in a fluidized bed opposed jet mill at 50 to 80m³Grinding together under air flow/h for 50 minutes at a grinding gas pressure of 7.0bar and a classifier speed of 18000s^-1. Also, purity was obtained>95% of the final product copper glycinate.

Working example 5:

1.791kg of methionine (12.0mol) and 0.477kg of copper oxide (6.0mol) were mixed in a fluidized-bed opposed jet mill at 50 to 80m³Milling under air flow/h for 55 min at a mill gas pressure of 7.0bar and classifier speed of 18000s^-1. Also, purity was obtained>95% of the final product copper methionine.

Working example 6:

1.900kg of lysine (13.0mol) and 0.517kg of copper oxide (6.5mol) were mixed in a fluidized-bed opposed-jet mill at 50 to 80m³Grinding together under air flow/h for 50 minutes at a grinding gas pressure of 7.0bar and a classifier speed of 18000s^-1. Also, purity was obtained>95% of the final product copper lysine.

Working example 7:

13.51kg of glycine (180mol) and 7.33kg of zinc oxide (90mol) were mixed in a fluidized-bed opposed-jet millAt 800 to 1200m³The mixture was ground for 4.5 minutes under an air flow at a grinding gas pressure of 7.0bar (80 ℃ C., uncooled compressed air) and a classifier speed of 4650s^-1. The corresponding zinc glycinate was characterized by IR spectroscopy. The amount of product obtained corresponds to an output of 280 kg/h.

Drawings

For a better illustration of the invention, reference is made to the accompanying drawings. The attached drawings show that:

FIG. 1: schematic representation of an apparatus for reactive grinding in a fluidized bed opposed jet mill;

FIG. 1 a: a side cross-sectional view;

FIG. 1 b: a top cross-sectional view;

FIG. 2 a: scanning electron micrograph of chelate of zinc-glycine (left);

FIG. 2 b: scanning electron micrograph of zinc oxide (right);

FIG. 2 c: particle size distribution measured on zinc bisglycinate;

FIG. 2 d: scanning electron micrographs of copper glycinate;

FIG. 3: ATR-IR spectra of glycine;

FIG. 4: ATR-IR spectrum of methionine;

FIG. 5: ATR-IR spectra of chelates of zinc-glycine;

FIG. 6: ATR-IR spectrum of chelate of zinc-methionine;

FIG. 7: ATR-IR spectrum of chelate of copper-glycine.

Detailed Description

Fig. 1 shows a schematic representation of the reactive grinding in a fluidized-bed opposed-jet mill 10, wherein the figure is limited to the essential elements of the apparatus. These are supplemented by not shown apparatus elements for raw material supply and introduction, product discharge, instrumentation, etc.

The fluidized-bed opposed-jet mills drawn are of the commercially available type, for example for very fine solids comminution (grinding, jet milling). In the embodiment example shown here, the mill is a fluidized bed opposed jet mill with a three nozzle system.

Fig. 1a schematically shows the apparatus, i.e. the fluidized bed opposed jet mill 10, in a side sectional view, while fig. 1b shows the same fluidized bed opposed jet mill 10 in a top sectional view, depicting the nozzle arrangement. Like parts are denoted by like reference numerals.

As can be seen from fig. 1a, the grinding chamber 1 is connected via a feed conduit 2 to a grinding stock reservoir 3, from which reservoir 3 grinding stock is fed into the grinding chamber 1. In this working example, a solid, premixed reaction grind is fed from a reservoir 3 in free-falling fashion, thus without additional energy input, through a feed conduit 2 into a grinding chamber 1, wherein the grinding chamber 1 provides or comprises a reaction space 1 for the reaction grinding according to the invention.

Alternatively, internals, such as distribution internals, and additional conveying means can be provided in the feed pipe 2, in particular in the case of addition not from above, but for example from the side. Furthermore, in an alternative embodiment not shown here, it is possible to keep the reactants in separate reservoirs and to mix them either immediately before the milling chamber 1, which can be done in one of the feed conduits 2 or in a separate mixing chamber. Alternatively, the reactants are delivered separately from their respective containers and metered into the milling chamber 1, where mixing can take place in the milling chamber 1 itself.

The fluid bed opposed jet mill 10 has at least two fluid nozzles 4 which must be arranged towards each other or at an angle relative to each other in order to create a collision zone in the centre of the nozzle arrangement.

As can be seen from fig. 1b, in the embodiment shown three fluid nozzles 4 for introducing the abrasive jets are depicted, wherein the vectors of the nozzle or jet directions intersect in a narrow defined area in which the particles collide and subsequently react with each other. The fluid nozzles 4 are arranged in a plane perpendicular to the drawing plane of fig. 1a and lie in the drawing plane of fig. 1b, in each case oriented at an angle of 120 ° to one another. A fluidized bed 5 consisting of abrasive and gas is formed in the center of the nozzle arrangement, i.e. in the collision zone, which is formed by means of the gas jet leaving the fluid nozzle 4.

The abrasive particles present in each case in the center of the fluid nozzles 4 opposite one another in the fluidized bed and the actual reaction space 5 formed thereby, where the reactants for the chelate-forming reaction of the invention are accelerated by the gas stream, so that after particle collision a chemical reaction and the formation of the relevant products are initiated.

The actual reaction space 5 in which the solid-state reaction takes place is located in the above-mentioned collision zone in the fluidized bed.

Fig. 2a shows a scanning electron micrograph of a sample of zinc glycinate (zinc bisglycinate) prepared according to the present invention compared with zinc oxide (ZnO) used as a starting material for the metal compound (fig. 2 b).

It can be readily seen that by the method of the present invention, dense particles are formed without a significant proportion of oversize particles, i.e. no needles of the zinc oxide feedstock are seen on the right side of figure 2 b. Thus, the product exhibits better processability and dispersibility. The particle size is within a narrow one-digit micron range with a narrow particle size distribution. Thus, the product is very uniform and has a high surface area. Thus, the product can be easily dispensed, e.g., finely dispersed in more complex compositions, metered, and easily compacted. The amino acid density and metal density in the product are high due to the absence of undesirable foreign salts and by-products.

The particle size distribution of the prepared zinc bisglycinate was examined more closely by means of laser light scattering, as described in working example 1 and shown in fig. 2 a. The results are shown in graph form in fig. 2 c.

The majority of the particles are about 1 to 4 μm in diameter. The narrow particle size distribution that can be read from the individual diameter curves is reflected in the typical ratio of (volume) D10, D50 and D90 values.

99% of the particles have a diameter of less than 10.00. mu.m (D)₉₉)，

90% of the particles have a diameter of less than 6.82 μm (D)₉₀)，

50% of the particles have a diameter of less than 3.41 μm (D)₅₀) And are and

10% of the particles have a diameter of less than 0.86 μm (D)₁₀)。

Further testing of other amino acid chelates of the invention yields D₅₀The value is 1 to 5 μm. Thus, D₅₀Preferably 1 to 5 μm, more preferably 1.5 to 3.5. mu.m.

In each case of examination, D₉₀The value is preferably 4 to 7 μm, and, D₉₉The values are all less than 15 μm.

Figure 2d shows a scanning electron micrograph of a further product of the invention, copper bisglycinate, prepared as described in working example 4.

Various amino acid chelates (for ZnGly)₂And CuGly₂) The microscopic photograph of (a) shows very clearly that the process gives a homogeneous and finely divided amino acid chelate uniformly regardless of the starting compound.

Fig. 3 to 7 show IR spectra which will be discussed in detail below.

Analytical method

In the preparation of the amino acid-metal chelate of the invention, the analysis of the compound and thus the occurrence of the (mechanical) chemical reaction is confirmed by the position of the Characteristic bands, the shape of the bands, the intensity of the bands of the Infrared spectroscopy (IR), see for example H.G ü nzler, H.U.G. Gremlich, IR-Spektroskopie, 4 th edition, Wiley-VCH GmbH & Co.KGaA, Weinheim, 2003; G.Socrates, Infrared and Rafracteric Group Frequencies: Tables and Charts, third edition, John Wiley & Sons, 2004; R.M.Silverstein, F.X.Webster, D.J.Kiemie, Spectrometric Identification of Organic Compounds, John Wiley & Sons, Sorns, J.Kiemie, spectral analysis of the Organic compatibility of Organic Compounds, John Wiley & sonsy, Horisc J.R.S.S.R.S.S.S. J.S. Pat.A, the reduction of the particle size of the sample, which is not affected by the conventional particle size reduction of the particle size of the product, which is measured by the conventional particle size of the sample, the particle size reduction of the sample, which is measured by the A.A.S.S.S.S.S.26. A, the particle size reduction of the particle size of the particle (see, the particle size of the sample, the particle size reduction of the sample, the particle size of the sample, the particle size reduction of the particle size of the sample, the particle size of.

For example, the structural features of zinc bismethionate can be found in R.B.Wilson, P.de Meister and D.J.Hodgson, Inorg.chem.1977,16,1498-1502 or M.Rombach, M.Gelinky, H.Vahrenkamp, Inorg.Chim.acta 2002,334, 25-33. In the present case, it is established by means of the spectral reference measurements that the products produced according to the invention are structurally identical to the reference materials produced by wet chemistry, which are sometimes commercially available. This is particularly emphasized because "American Association of feed control Officials" (AAFCO) defines the chelate as the reaction product of a metal ion of a soluble metal salt and an amino acid (see, e.g., s.d. ashmead, m.pedersen, US 6426424(B1) 2002). In particular, the formation of chelates is confirmed by a significant change in the IR spectrum during the production process of the present invention, which will be illustrated below with the aid of suitable examples.

ATR-IR analysis, demonstration of chelate formation Spectrum

The change in the nitrogen-hydrogen stretching vibrational position of the NH of the ammonium group during IR analysis is particularly important in order to demonstrate the formation of chelates when carrying out the process of the present invention. In the case of the amino acid glycine (FIG. 3), the band is from a wave number (cm) of about 3150^-1Abscissa units of infrared spectroscopy) are shifted; in the case of methionine, the band ranges from less than 2950cm^-1(FIG. 4) Shifting, by chelate formation, to about 3440cm for Zinc glycinate^-1(FIG. 5), or about 3295cm for zinc methionine^-1(FIG. 6). The difference in wave numbers that occurred indicates that the nitrogen atom is involved in the complexation, thereby forming the chelate itself. In this regionHigher than 3000cm in domain^-1Can be substantially attributed to the presence of crystal water. Furthermore, there are strong harmonics of the fundamental vibrations found in the higher fingerprint areas. Stretching vibrations v of the asymmetric carboxylate of amino acids initially present_as(COO^–) Appear at about 1575cm^-1To (3). During chelate formation, the position thereof hardly moves. Position v of a symmetrical overhang of the carboxylate oscillation_sym(COO^–) And also remains stable. However, chelate formation during the reaction of the present invention can also be clearly identified in this upper fingerprint region, since only free amino acids are detected at about 1500cm^-1Has deformation vibration (delta)_sym(NH₃ ⁺) E.g. delta_sym(NH₃ ⁺Glycine): 1498cm^-1，δ_sym(NH₃ ⁺Methionine): 1514cm^-1，δ_sym(NH₃ ⁺Lysine): 1511cm^-1) But it disappears during reactive milling and chelate formation. The corresponding metal-nitrogen vibrations in these chelates are found only at low wavenumbers in the lower fingerprint region, e.g. at 419cm^-1Met-N (zinc methionine) at (c), due to the higher atomic mass of the metal. A significant change in the IR spectrum of the metal chelate, compared to the corresponding spectrum of the free amino acid, is also clear evidence of chelate formation during the process of the invention.

In the case of copper bisglycinate in comparison with the starting glycine, in the IR region of the chelate band at about 3330, 3260 and 3160cm^-1There is a signal (see fig. 7).

Summary of the invention

The present invention provides an energy-efficient process for the preparation of amino acid-metal chelates in the absence of solvent. The energy saving compared to the previous process is due firstly to the fact that no wet chemical reaction and subsequent drying are required. Despite the mechanochemical reaction achieved, unlike the prior art, no grinding media and no additional mass, such as counterweights, are required for the reaction in an eccentric vibratory mill. Thus, the process product is free of abrasive metals in the grinding media. The mixture of the starting amino acid/hydroxycarboxylic acid and metal oxide, metal carbonate or metal oxalate fed at atmospheric pressure is preferably converted mechanochemical reaction into the corresponding metal chelate only by means of the impact of the particles caused by the gas stream in a fluidized-bed opposed-jet mill (gas jet) against the fluid jet. The energy efficiency is also due to the fact that the inventive method operates solely by means of the abrasive gas jet, without the additional introduction of thermal energy, radiant energy, etc. It is therefore a novel autoreactive process for the complete chemical conversion of a feedstock, such that an organic acid, preferably a naturally occurring amino acid, such as glycine, methionine or lysine, is combined with an oxide, carbonate or oxalate of a trace element metal, in particular zinc, copper, manganese, selenium, iron, calcium, magnesium, nickel, cobalt, vanadium, chromium or molybdenum. The feed additives and nutritional supplements sought are obtained in this way, for example zinc (di) glycinate, zinc (di) methionine, zinc (di) lysine, copper (di) glycinate, copper (di) methionine, copper (di) lysine and the like. It is likewise possible to use hydroxycarboxylic acids instead of amino acids, which leads firstly to food additives; other (industrial) uses of such chelating compounds are known. The process product is obtained in an extremely structurally homogeneous and extremely pure form. Thermal stress or decomposition of the organic chelate ligand, particularly the amino acid, is avoided, as is contamination of the abrasive material from the mill and the grinding media.

In contrast to known methods using various mills, for example eccentric vibratory mills, the fluidized bed opposed jet mill is also operated in a continuous operation.

The reaction water is removed with the grinding gas without additional energy input.

Reference numerals

10 fluidized bed opposed jet mill

1 grinding chamber

2 feeding pipe

3 storing device for grinding material

4 fluid nozzle (grinding gas nozzle)

5 fluidized bed (reaction space)