WO2001000556A1

WO2001000556A1 - Dust-free calcium formate

Info

Publication number: WO2001000556A1
Application number: PCT/EP2000/005415
Authority: WO
Inventors: Achim Noack; Hanspeter Baumgartner; Jürgen STRUSCH; Alexander Klausener; Mélanie JURET
Original assignee: Bayer Aktiengesellschaft
Priority date: 1999-06-26
Filing date: 2000-06-13
Publication date: 2001-01-04
Also published as: DE19929346A1; NO20016244L; CN1358166A; AU5681000A; HK1046130A1; NO20016244D0; EP1196368A1; JP2003503376A

Abstract

Dust-free formulated calcium formate can be obtained by means of agglomeration, especially mixing agglomeration, from finely crystalline calcium formate having a significant proportion of fine-grains and of dust while adding at least one auxiliary agent.

Description

Dust-free calcium formate

The present invention relates to a process for the production of a material which contains dust-free assembled calcium formate of the formula Ca (HCOO) ₂ , wherein finely crystalline calcium formate is subjected to agglomeration with the addition of at least one auxiliary and optionally one or more further components. Furthermore, the invention relates to the use of this material and correspondingly available dust-free assembled calcium formate.

Calcium formate is a light, crystalline solid that is used commercially, for example, in the following areas:

Additive in the field of animal nutrition (pig, cattle and turkey fattening)

Use in the building materials industry (improvement of the hardening of cement, plaster and grout as well as antifreeze for mortar)

- Production of formic acid

Auxiliary in the leather industry

Aid in the production of glossy papers

Treatment of wash water in flue gas desulfurization

Aid for ensiling.

Calcium formate is obtained in various ways, for example by reacting formic acid with calcium hydroxide or by the action of carbon monoxide on calcium hydroxide. Such syntheses are described for example in Ullmann's Encyclopedia of Industrial Chemistry (4th edition), Vol. 7, pp 364 and 370, and in Ullmann's Encyclopedia of Industrial Chemistry ^(5th edition) Vol. A 12, page 29.

The technically most important extraction of calcium formate takes place according to various processes known from the literature for the production of polyols, in which calcium formate is obtained as a by-product. The production of trimethylolpropane from n-butyraldehyde and formaldehyde using calcium hydroxide as the base may be mentioned here by way of example. Calcium formate is produced as a by-product in this process.

Calcium formate can be crystallized, isolated and purified using suitable techniques known per se. Evaporation crystallization of aqueous solutions which may contain organic components, cooling crystallization and spray drying may be mentioned as examples of crystallization techniques which can be used in principle. Filtration or centrifugation may be mentioned as examples of basically suitable isolation techniques. Possible cleaning operations include redissolution, dispersion, washing and extraction with suitable solvents. Where appropriate, such operations or operation sequences are followed by another suitable drying step, of which hot air drying, contact drying and vacuum drying are mentioned as examples of basically suitable methods.

All these processes have in common that they deliver polydisperse products that are characterized by characteristic, more or less broad particle size distributions. In all known technical processes for the production of calcium formate, particularly in the fine-grained area with particle diameters <0.2 mm, significantly high proportions of the total crystallizate are found. For various purposes, however, a product that has a low proportion of fine grains is preferably required owns and does not dust during processing. Reasons for this can lie, for example, in certain requirements of occupational hygiene, according to which the handling of calcium formate containing dusty parts can cause problems which can only be remedied with additional technical measures. Other reasons depend on the physical behavior of fine-grained, significant amounts

Calcium formate containing dust. If calcium formate, for example, is introduced into certain commercially available coarse-grained, structured or shaped animal feed or silage components that contains high levels of fine grains or dust, this is often associated with considerable mixing problems and undesirable segregation in the further handling of the finished mixture. These effects can limit the advantageous use of calcium formate in many areas of application. Although it is possible to separate coarse-grained fractions with the help of suitable techniques such as classifying, screening and sifting, on the one hand additional costs are incurred, on the other hand the remaining fine-grained or dust-like fractions can only be used with considerable additional effort by for example, they are redissolved, crystallized, isolated, dried and then returned to the fractionation process. Especially in processes in which calcium formate is only obtained as a by-product, it is often not technically and economically sensible to isolate what is preferred

Modify the main product so that calcium formate is obtained in the most coarse or dust-free fractions possible.

In principle, various agglomeration techniques are available for converting fine-grained or powdery solids into coarse-grained material, the use of which can in principle also be considered in the case of crystalline calcium formate. For processing reasons, it is often desirable to maintain the good flowability of the calcium formate. Attempts to moisten calcium formate, for example by adding small amounts of water, so that, based on the sticking together of fine particles, larger ones

Crystal dressings arise due to the hygroscopic properties of Dry calcium formate in general for the formation of inhomogeneous material, which contains undefined coarser components in addition to unchanged fine-grained components.

DE-OS-1 518 686 discloses a process for granulating calcium formate, according to which a high proportion (55 to 65% based on the amount of granules obtained) of granules with a diameter of 2 to 5 mm is obtained. Magnesium oxide must be added to the calcium formate to be granulated and the mixture sprayed with aqueous magnesium chloride solution. The result is a material which contains 2.2 to 23.4% by weight of magnesium compound, calculated as magnesium oxide. It is not possible to obtain magnesium-free material by this method. Nothing is said about the dust behavior of the granules.

With regard to the production of a wide variety of animal feed products and ensiling aids, the task was therefore to produce a material based on calcium formate with the smallest possible fine grain fraction, which allows dust-free further processing and has good flowability. A technically viable, economical way of producing such a product should be found. This object is achieved by the method according to the invention.

It has surprisingly been found that, contrary to negative test agglomerations, dust-free calcium formate with satisfactory application properties can be obtained during further processing if polydisperse calcium formate with a high proportion of fine grains or dust, ie calcium formate which is at least 50% by weight, preferably contains at least 60% by weight of particles with an average particle size of less than 0.2 mm, preferably less than 0.1 mm, with the addition of suitable auxiliaries which promote agglomeration and, if appropriate, further components which do not or only marginally influence the agglomeration that the small calcium formate particles, which can cause dust formation, by said auxiliary agent to be used according to the invention to larger calcium formate particles are bound and / or are combined to form larger particles under the action of said auxiliary substance, the resulting high particle sinking speeds leading to the avoidance of undesired dusting. Calcium formate with a high proportion of fine particles or dust, ie calcium formate containing at least 50% by weight of particles with an average particle size below

Contains 0.2 mm, for example, is a by-product of a process for the production of polyols.

The invention accordingly relates to a process for the production of material which contains dust-free calcium formate and is characterized in that finely crystalline calcium formate which contains at least 50% by weight, preferably at least 60% by weight, of particles with an average particle size below 0 , 2 mm, preferably less than 0.1 mm, is subjected to agglomeration with the addition of at least one auxiliary substance. Furthermore, the invention relates to the use of this material as an additive in the field of animal nutrition and dust-free assembled calcium formate which contains less than 20% by weight of particles with a maximum grain size of 0.05 mm and can be obtained by the process according to the invention.

The inventive method leads in a technically easy to implement and

Way to material containing calcium formate, which can be handled dust-free and shows good flow behavior.

According to the invention, the agglomeration can in principle be obtained by all known and conceivable methods of structural agglomeration, for example by

Mixed agglomeration, plate agglomeration, rotor agglomeration, fluidized bed agglomeration and steam jet agglomeration.

The calcium formate, which is made up dust-free according to the invention, is preferably produced by mixed agglomeration. The calcium format used as the starting material is mixed with a suitable auxiliary. The mixing agglomeration can be carried out using a solid mixer with moving tools. Mixers with high mechanical power input are generally preferred. Such mixers are also referred to as intensive mixers. The greater the mechanical power input, the better the flowability of the agglomerated product.

The agglomeration of calcium formate according to the invention can in principle be carried out either continuously or batchwise. It is carried out with the aid of devices known to the person skilled in the art, preferably those which are available from specialist dealers. For the preferred mixed agglomeration, the continuous

Operation of the so-called ring layer mixer is preferable.

Any calcium formate can be used as calcium formate that contains significant fine grain or dust, i.e. contains at least 50% by weight, preferably at least 60% by weight, of particles with an average grain size below 0.2 mm, preferably below 0.1 mm. Calcium formate is preferably used, as is typically obtained after isolation and purification as a by-product of a process for the production of polyols such as trimethylolethane, trimethylolpropane or pentaerythritol.

The calcium formate to be subjected to the agglomeration can in principle be introduced into the agglomeration device, optionally with the addition of further auxiliaries and / or components, with the aid of all conveying units known to the person skilled in the art. Conveyor belts, screws and vibrating troughs may be mentioned as examples.

The auxiliary material used according to the invention can be introduced into the mixer in liquid or solid, approximately powdered form. The introduction in liquid form is preferred. Auxiliaries that are solid at room temperature can optionally be melted and fed to the agglomeration process in the form of a melt. - 1 -

The finely crystalline calcium formate, the auxiliaries and, if appropriate, the further components can each be introduced into the agglomeration apparatus individually or in any mixture. The order of introduction is irrelevant. The finely crystalline calcium formate is preferably introduced and then the auxiliaries and optionally the further components are added.

The agglomeration according to the invention can take place, for example, in a temperature range between -70 and 150 ° C., preferably in the temperature range between -20 and 110 ° C., particularly preferably in the temperature range between 0 and 75 ° C.

The auxiliary substance contents in the material produced according to the invention are generally in the range between 0.1 and 20% by weight, preferably in the range between 0.3 and 15% by weight, particularly preferably between 0.5 and 8% by weight on the resulting ready-made material. Depending on the auxiliary used, the

Use of a minimum excipient content of up to 6 wt .-% may be advantageous.

Auxiliaries used according to the invention can be, for example, liquid or solid auxiliaries which are known to the person skilled in the art as compacting and formulation auxiliaries. Examples of such auxiliaries are water, optionally aqueous mineral acids, mono-, di-, tri- and polyhydric alcohols such as ethylene glycol, propane-1,2-diol or glycerol, carboxylic acids, carboxylic esters, carboxamides, sulfoxides, fats, especially hard fats, Fatty acids, in particular isomergic acid, fatty alcohols, waxes, tallows and oils of synthetic or natural (animal or vegetable) origin. Be further as possible

Auxiliaries called mono-, di-, oligo- and polysaccharides such as glucose, sucrose, lactose, dextrins, starch, cellulose, cellulose derivatives or technical molasses. It is also possible to use mixtures of the auxiliaries mentioned. Preferred auxiliaries are ethylene glycol, propane-1,2-diol, glycerol, fats, isomergic acid and / or waxes, tallow and oils of synthetic or natural (animal or vegetable) origin.

Ethylene glycol, propane-1,2-diol, glycerol, fats and / or are particularly preferred

Isomerginsaure®.

If appropriate, it may be expedient to carry out targeted cooling of the material obtained after agglomeration in order to prevent uncontrolled solidification and caking during storage or further processing after

To prevent bottling.

In principle, it is also possible and therefore also an object of the invention to add one or more other substances to the production of the dust-free assembled calcium formate in addition to the auxiliaries mentioned, which, if appropriate, do not influence the process of agglomeration or only slightly, but additionally bring about desired application-related effects.

Substances which can possibly have a positive influence on the application properties and / or the further use of the lumpy calcium formate according to the invention are, for example, fragrances, flavorings, carbon such as activated or medicinal carbon, preservatives, and various inorganic or organic salts of natural or synthetic origin. Sodium, potassium, ammonium, magnesium, calcium and iron salts and chlorides, sulfates, phosphates, silicates, carbonates, bicarbonates, acetates, benzoates and citrates with any counterion or counterions may be mentioned by way of example.

Other mixing partners that have a positive influence on the use of the product according to the invention can, for example, in particular in the field of animal nutrition, be performance-promoting and / or nutritionally active substances. Examples include special feed ingredients, vitamins and pharmaceuticals in the broadest sense. It is also possible to add mixtures of different additives.

Mixing the calcium formate with a high proportion of fine grain or dust, i.e. of calcium formate, which is at least 50% by weight, preferably at least 60

% By weight of particles with an average grain size of less than 0.2 mm, preferably less than 0.1 mm, with the other substances mentioned can take place, for example, in the course of agglomeration, preferably mixed agglomeration. In principle, premixing is also possible in any mixing unit, after which the premixed material is fed to the actual agglomeration step. This can be done in practically all suitable ways known to those skilled in the art. For example, pre-mixing in mixers with moving mixing tools, in free-fall mixers, with the aid of screws, by pneumatic mixing (pneumatic swirling), by grinding in all suitable mill types, by mixing screening, by uniform wetting or by wetting pre-agglomeration. In principle, several of the substances mentioned can also be mixed with the calcium formate used according to the invention and fed to the subsequent agglomeration and transfer into the material containing calcium-free iate which is made up according to the invention without dust.

The substances mentioned and the calcium formate used as the starting material can in principle be mixed with one another in any proportions, although there are only restrictions due to the physical consistency of the mixtures obtained - they must ultimately lead to solid, sufficiently free-flowing products after assembly.

In the case of the calcium formate which has been made up dust-free according to the invention, in the event that one or more additives have been admixed with it in the course of its production according to the invention, the proportion of pure calcium formate is generally between 5 and 99.9% by weight, preferably between 25 and 99.7 % By weight, particularly preferably between 50 and 99.6% by weight and particularly preferably between 75 and 99.5% by weight.

According to the method according to the invention, it is possible, for example, to obtain dust-free assembled calcium formate which is between 0.1 and 20% by weight, preferably between 0.1 and 15% by weight, particularly preferably between 0.1 and 10% by weight an auxiliary and contains less than 20 wt .-%, preferably less than 18 wt .-% of particles with a maximum grain size of 0.05 mm.

The method according to the invention is further illustrated by the following examples, the invention being in no way restricted to these examples.

Beisniele

example 1

In an intensive mixer from EIRICH (type R02, nominal volume 5 1), 4.5 kg were

Calcium formate from the production of trimethylolpropane (co-product), which contains at least 50% by weight of particles with an average grain size of less than 0.2 mm. The vertebrate was operated at a speed of 3000 min ^"1. This speed corresponds to a Froude number Fr = 700 with the following definition of the Froude number:

Fr = ω ² • R / g with ω = 2 • π • n [s ^{~ 2} ] angular frequency n [s ¹ ] mixing tool speed

R [m] radius of the rotating mixing tool g [m / s ² ] gravitational acceleration

Various auxiliaries (see Table 1) were sprayed in liquid form with the aid of a single-component nozzle or introduced into the mixer in the form of a jet. An influence of the type of additive was not discernible in the respective preliminary tests. The auxiliary substances solid at room temperature (hard fat (fatty acid glyceride) of

Types Witocan ^® HS and Witocan ^® 42/44, vegetable fat, isomergic acid and hard fat (fatty acid glyceride) of the Dynasan ^® 60 type) were liquefied by heating to a temperature which was about 20 K above the respective melting point.

In addition to various auxiliaries, different agglomeration times were selected (see Table 1). The excipient contents given in table 1 represent mass fractions (mass excipient / mass calcium formate).

The dust-free nature of the products obtained was assessed visually by spilling from one container into another. The bulk density was measured in a vessel the volume of 1.0 liter, into which the product was poured without further compression.

The flow behavior of the products was assessed by funnel outlet tests. Funnels (volume approx. 200 ml) with different funnel outlet diameters were used. The product was filled into the respective funnel without being sealed while the outlet was closed. The outlet opening was then opened and it was observed whether the product flows out freely or whether a bridge or a shaft forms above the outlet opening. Table 1 shows the minimum funnel outlet openings required for trouble-free flow. It was shown that the Witocan ^® HS hard grease leads to the most favorable flow behavior.

The samples treated with auxiliaries had a reduced bulk density and no longer showed any dust generation.

When using the various auxiliaries, different minimum binder contents are advantageous in order to guarantee complete freedom from dust. If 1,2-propanediol and water are used, minimum contents of 0.5% by weight and 0.6% by weight are advantageous, in the case of hard greases of types Witocan ^® 42/44 and

Dynasan ^® 60 is 6.0% by weight.

Table 1

Example 2

In a ploughshare mixer from LÖDIGE (type 5MR, volume 5 1), 3.0 kg of calcium formate from the production of trimethylolpropane (co-product) containing at least 50% by weight of particles with an average grain size of less than 0.2 mm were submitted. The plowshares were operated at a speed of 274 min ^"1. This speed corresponds to a Froude number of Fr = 8.

Various auxiliary substances (see Table 2) were sprayed in liquid form with the aid of a single substance nozzle or introduced into the mixer in the form of a jet. An influence of the type of additive was not discernible in the respective preliminary tests. The auxiliaries which are solid at room temperature (hard fat (fatty acid glyceride) of the Witocan ^® HS type and isomergic acid) were liquefied by heating to a temperature which was about 20 K above the respective melting point.

In addition to different auxiliaries, different agglomeration times were selected (see Table 2). Set the excipient contents given in table 2

Mass fractions (mass binder / mass calcium formate). The freedom from dust the products obtained were assessed visually by spilling from one container into another. The bulk density was determined in a 1.0 liter volume into which the product was filled without further compression.

The flow behavior of the products was assessed by funnel outlet tests. Funnels (volume approx. 200 ml) with different funnel outlet diameters were used. The product was filled into the respective funnel without being sealed while the outlet was closed. The outlet opening was then opened and it was observed whether the product flows freely or forms a bridge or shaft above the outlet opening. Table 2 shows the minimum funnel outlet openings required for trouble-free flow.

It was shown that, in comparison to the experiments in the EiRiCH intensive mixer (example 1), a higher content of auxiliary material is necessary for all auxiliary materials in order to ensure freedom from dust.

Table 2

Example 3

Calcium formate from the production of trimefhylolpropane (by-product)) containing at least 50% by weight of calcium formate was produced in a continuously operating ring layer mixer from LÖDIGE (type CB 30 P, diameter 300 mm, length: 1250 mm, mixing tools: pens and paddles) Contains particles with an average grain size of less than 0.2 mm, and melted hard fat (fatty acid glyceride) of type Witocan HS (temperature of the melted fat: 50 ° C - 60 ° C) mixed. The calcium formate was fed continuously to the annular layer mixer by means of a metering screw and the molten hard fat by means of a peristaltic pump.

Tests were carried out at different levels of the auxiliary (mass of auxiliary / mass of calcium formate), at different speeds and at different flow rates (see Table 3).

The agglomeration at the low speed of 850 min ^"1 leads to a product with poorer flow properties than at higher speeds (1500 min ^{" 1} and 2000 min ^"1 ). The minimum level of hard fat of the type Witocan HS, which is advantageous for dedusting, can be reduced to 0.7 This reduction in hard fat content results in better flowability of the product.

Table 3

Claims

claims

1. A process for the production of material which contains dust-free calcium formate, characterized in that finely crystalline calcium formate which contains at least 50% by weight of particles with an average grain size of less than 0.2 mm is subjected to agglomeration with the addition of at least one auxiliary ,

2. The method according to claim 1, characterized in that the material obtained is subjected to cooling immediately after agglomeration.

3. The method according to at least one of claims 1 to 2, characterized in that the agglomeration takes place in one or more stages by mixed agglomeration, plate agglomeration, rotor agglomeration, fluidized bed agglomeration or steam jet agglomeration.

4. The method according to at least one of claims 1 to 3, characterized in that the agglomeration takes place by mixed agglomeration.

5. The method according to at least one of claims 1 to 4, characterized in that the auxiliaries are present in a proportion of 0.1 to 20 wt .-%, based on the resulting finished material.

6. The method according to at least one of claims 1 to 5, characterized in that the auxiliaries are solid or liquid binders, compacting or formulation auxiliaries.

7. The method according to at least one of claims 1 to 6, characterized in that the solid or liquid binders, compacting and formulation auxiliaries are diluted with water, optionally with water Mineral acids, mono-, di-, tri- and polyhydric alcohols, carboxylic acids, carboxylic acid esters, carboxamides, sulfoxides, fats, fatty acids, fatty alcohols, waxes, tallows and oils of synthetic or natural (animal or vegetable) origin, mono-, di-, Oligo- and polysaccharides or technical molasses.

8. The method according to at least one of claims 1 to 7, characterized in that the finely crystalline calcium formate, which contains at least 50 wt .-% of particles with an average grain size below 0.2 mm, was obtained as a by-product of the technical production of polyols.

9. The method according to at least one of claims 1 to 8, characterized in that one or more further components are added in the agglomeration.

10. The method according to claim 9, characterized in that fragrances, flavors, carbon, preservatives, inorganic salts and / or organic salts are added as further components.

11. The method according to at least one of claims 9 to 10, characterized in that the other components are performance-enhancing and or nutritionally active substances, vitamins and or pharmaceuticals.

12. Dust-free made up calcium formate, which contains between 0.1 and 20 wt .-% of an auxiliary according to claim 6 and less than 20 wt .-% of particles with a maximum grain size of 0.05 mm.

13. Use of a material according to at least one of claims 1 to 12 as an additive in the field of animal nutrition.