DE202006020016U1 - Mineral granules - Google Patents

Abstract

mineral Granules, in particular animal scattering granules, bedding granules in construction, oil and / or Chemical binder granules, essentially of agglomerated, at least microporous, preferably having micropores and macroporous calcium silicate hydrate material grains Granules with a bulk density according to DIN EN 1097-3: 1998, less than 750 g / l and a proportion of flour meal in each granule with grain sizes below 1000 μm, in particular below 500 μm, between 30 and 100% by weight, in particular between 40 and 100% by weight, based on the dry matter of the granules, in particular size Granules contain proportionally lower levels of flour meal than smaller ones.

Description

The The invention relates to a mineral produced by granulation porous Granules. Such granules are used in particular as adsorbents for liquid media, e.g. as animal litter or oil binder used.

Known is, highly absorbent Granules of crushed and classified pore or foam concrete granules to be used as animal litter. In particular, such granules are advantageous that the bulk density only 300 to 500 g / l and the granules can be a waste product.

Known are also bentonite-based granules. Bentonite is a high-absorbency clay mineral, which swells to a considerable extent after contact with water and forms agglomerates. When using bentonite as animal litter Lumps form, which are easily removed from the remaining litter and can be disposed of. disturbing Odor development can be avoided by using liquid contaminated parts of the litter are removed and the remaining Litter continues to be used, reducing the consumption of litter can be reduced. Disadvantages of using pure bentonite are the costs for the raw material and the high bulk density from 900 to 1,000 g / l. (The bulk weights are within the scope of the invention according to DIN EN 1097-3: 1998 determined Bulk densities).

It were about it already efforts to combine the advantages of both products.

From the DE 195 09 747 A1 is a porous granules for ad- or absorption of liquids and gases, in particular for use as hygiene animal litter known, which consists of a clay mineral component covered aerated concrete grains and whose grain size between 0.5 and 4, preferably between 0.5 and 2 mm should lie. The clay mineral component should be in finely divided form as flour, whereby the swelling capacity should be favored. Depending on the production process, the porous support material should be available in different bulk densities and particle sizes, bulk densities of 300 and 400 g / l being preferred. For the production, water and bentonite flour are processed to a slurry with a thin sludge, into which aerated concrete material with a particle size of less than 1.5 mm is sprinkled. This primary grain should be microporous calcium silicate and coated in the mixing process with a uniform layer thickness of the bentonite slurry, the finished granules should have a size of about 2 mm. An average bulk density of these granules is given as about 450 g / l. The proportion of highly swellable clay mineral should range from 25 to 50 wt .-% and the proportion of cellular concrete or Calcium Silkathydratmaterials should be between 50 to 75 wt .-%. Viewed in cross-section, the granules have a relatively large core of porous calcium silicate hydrate material and a relatively thin coat of bentonite to the core. According to this document, a rewetting of the granules dried in a stream of hot air can also take place in order to impart further finely divided bentonite and thus to increase the layer thickness of the bentonite to a specific thickness.

From the EP 0 716 806 A1 Also, there is known a granule for use as an animal litter wherein 25 to 70 parts by weight of a highly swellable material and 30 to 75 parts by weight of a porous concrete granules are used. According to this document, it is in addition to the embodiments according to the DE 195 09 747 A1 it is possible to mix both materials in such a way that a cross-sectionally homogeneous structure within the granule is achieved. The autoclaved aerated material should have particle sizes of <0.5 mm with a bentonite content of around 25% by weight in order to produce a granulate of homogeneous composition.

Furthermore, from the DE 198 43 887 B4 a hygienic granules based on calcium silicate hydrate and bentonite, according to which the granules pelleted granules having a two-layer structure with a core and a shell or shell, wherein the core predominantly calcium silicate hydrate and the shell comprises a mixture of finely divided, swellable clay mineral and finely divided calcium silicate , The advantage of this granulate is that the shell of a mixture of finely divided, swellable clay material and finely divided calcium silicate hydrate in the absorption of liquid is not impermeable and thus a relatively large proportion of the liquid can be forwarded into the core.

at a use of such granules as animal litter or plant granules a particularly high abrasion resistance is desirable because the granules be used in the direct living or living area of humans and thus should not cause dust or abrasion.

In This connection is made in particular by processing and binding of flourish or dusty Material problems by making the material look bad in the making mix and integrate and in the finished product for detachment and thus tends to form abrasion and dust.

The object of the present invention is to provide a granule which has a high adsorption capacity and a high storage capacity for liquid As well as good strength, a good abrasion stability and a good odor retention. In addition, the granules should also be inexpensive to produce from waste materials and be as light as possible, in particular gray to white product. Furthermore, the granules should not be toxic, environmentally friendly and temperature stable at normal room and outside temperatures.

It was surprisingly found that a granules of granules very good adsorption properties, in particular has very good animal litter properties that can be produced is made from at least one flour-shaped or at least one flour-shaped and grainy Calcium silicate hydrate material, such as granular and / or finely divided or flour-shaped Pore or foam concrete material. The new granules in particular also a relatively smooth surface and guaranteed a very large amount of water intake and a relatively low bulk density from e.g. <650 g / l. As a special effect, the granules of the invention in principle a bright to white pleasing Color and in particular because of this in a simple way colored become.

When Another advantage is that a starting material of granule granules according to the invention, namely Calcium silicate hydrate material, especially as pore and / or Foamed concrete waste material, in particular predominantly tobermorite as a mineral having, in the production of pore and / or foam concrete accrues. In particular, in the industrial production of pore and / or foam concrete moldings as well as the splitting of pore and / or Schaumbetonquadern flour fractions of these materials, which are used to produce the granule granules according to the invention be used.

To a variant of the invention is also granular calcium silicate hydrate material, particularly in the form of aerated concrete and / or foam concrete fracture material, used together with the flours.

The Granules of granules have good grain strength for use as bulk material and a good flowability and so that a good compressibility at e.g. vibration effects on.

The The present invention thus relates to a granule of granules comprising Granules made by granulating mixtures of water and at least the components calcium silicate hydrate material in Flour or in flour form and in granular form.

The equivalent terms floury or powdered or dusty or finely divided in the context of the present invention mean finely divided particle sizes in normal, production-related particle size distribution up to 1000 μm; Grainy means grain sizes of 1000 μm to e.g. 8 mm. (The following is for the finely divided fractions mainly the term flour, or flour fraction or flour-like used.)

Under Granules that form the granules of granules are within the framework of the Invention intrinsic grainy To understand products by an agglomerating granulation process and not made by breaking or grinding and the good ones pourable are and their grains one for the particular application sufficient to very good, relatively have abrasion-resistant mechanical strength. Due to the Production of the granules results in a relatively narrow particle size range e.g. with Gaussian Grain distribution and approximate uniform geometric shape, e.g. with spherical shape and / or approximate spherical shape, of the granules. The granules are e.g. completely made of flour or dust or Powder produced alone or together with granular material, as granules with rounded surface contours. That for the production the granules used is pore and / or foam concrete material preferably waste material from the pore and / or foam concrete production, the for the preparation of the products according to the invention optionally prepared, e.g. is broken down or ground and classified.

With Calcium silicate hydrate material or aerated concrete and foam concrete material is in the context of the present invention, in particular at least Microporous exhibiting, preferably a microporous and swelling or Foam pores resulting macroporous synthetic, hydrothermal produced material referred to. It is in particular a pore and / or Foamed concrete material, in particular mainly the mineral tobermorite having the pore and / or foam concrete material pore- and / or foam concrete flour and / or granular pore and / or foam concrete material with common e.g. Gaussian Grain distribution, but also material with failure grain between a flour fraction and a grainy Can be fraction.

preferred have granules according to the invention preferably from 20 to 100% by weight, in particular from 50 to 100% by weight, of pore and / or foam concrete flour, based on the dry calcium silicate hydrate ingredients of the granules. A respective remainder may be from the granular material consist.

For a first embodiment of the granules, at least one flour of at least one calcium silicate hydrate material is introduced into a so-called pelleting mixer or granulating mixer and mixed in the mixer with water during mixing, for example, sprayed or sprayed, so that granulation or agglomeration or pelletization takes place. (The terms granulation, agglomeration and pelleting are used equivalently in the context of the present invention, but granulation is preferred.)

To Achieving a granule granules with a predetermined granule size and / or Granule size distribution Granules Grana the pelletizer is removed from the Grana and dried.

As calcium silicate hydrate products are used from a CaO and a SiO ₂ component in the usual way hydrothermally cured, microporous products used, and / or calcium silicate hydrate products that have been subjected to a swelling process before the hydrothermal hardening, or before the hydrothermal hardening Foam was added, so that in the cured product in addition to water channels and channels formed between CSH crystals micro pores and macropores are present. The latter are in particular aerated concrete or foam concrete products, of which in the context of the invention preferably the waste products are used in granular form (fractions) and in flour form (dust products) in order to solve waste problems. The fractions may optionally be further comminuted and graded to provide granular grades of particular grain distributions, or they may be ground to produce granular flours unless sufficient dust rejects are present.

Particularly suitable are starting calcium silicate hydrate products from flour with the following particle size distribution:
1000 to 2000 μm: 3 to 8 wt.%,
500 to 1000 μm: 20 to 33% by weight,
125 to 500 μm: 40 to 57% by weight,
up to 125 μm: 20 to 35% by weight,
especially
1000 to 2000 μm: 4 to 7% by weight,
500 to 1000 μm: 23 to 27% by weight,
125 to 500 μm: 42 to 48 wt.%,
to 125 microns: 23 to 27 wt .-%.

It It has been found that in particular the flours from aerated concrete and foamed concrete products particularly well, apparently because of their surface structure in combination with the micropores favors the agglomeration.

The Flour products are e.g. with water contents of 2 to 30% by weight, in particular from 22 to 35% by weight and with flour meal sizes up to 1200 microns, in particular up to 1000 μm, as well as normal Gaussian Grain distributions used.

the To be granulated material from flour is preferably during the Mixing water in amounts of 15 to 50 wt .-%, in particular of From 20 to 30% by weight, based on the amount of flour, e.g. by spraying or injecting added to the mixer and granulation with relatively low mixing energy effected in the mixer. The mixing component parameters and the granulating energy adjusted so that a free-flowing granules is produced with relatively abrasion-resistant granules whose spatial form substantially rounded, e.g. is substantially spherical, with Grain sizes between 1 and 3 mm, in particular between 1.5 and 2.5 mm, as well as water contents between 30 and 45% by weight, in particular between 36 and 39% by weight, on. After drying is the water content 2 to 15 wt .-%, in particular 3 to 8 wt .-%, and the bulk density is 450 to 750 g / l, in particular 600 to 700 g / l, and the water absorption is 70 to 130 wt .-%, in particular 80 to 110 wt .-%.

to Binding of sometimes residual dust on the granules is it convenient, in one Post-granulation process cellulose ethers, especially in the form of carboxymethylcellulose, e.g. of alkali metal carboxyl methylcellulose, such as sodium carboxymethylcellulose and / or potassium carboxymethylcellulose, to be added, preferably in amounts of 0.2 to 2 wt .-%, in particular from 0, 2 to 1, 0 wt .-%, based on the calcium silicate hydrate product. The cellulose ethers assist clean the granules. Another advantage of this additive is that it is in an amount of 3 to 10% by mass in the usable granules, e.g. When used as litter, causes lumping and water absorption elevated.

It is advantageous, more usual Additives, such as dyes, fragrances, odor-binding substances, Pigments, catalysts, fertilizers or to add indicators, e.g. Perfumes in amounts up to 1% by weight, based on the dry matter of the granules.

A granule produced according to this first embodiment of the invention has granules which contain:
From 78 to 97% by weight of calcium silicate hydrate material meal,
3 to 20% by weight of adsorptively bonded water, after drying,
0 to 2% by weight of carboxymethylcellulose,
especially
90 to 91% by weight of calcium silicate hydrate material flour,
4 to 9% by weight of adsorptively bound water,
0 to 1% by weight of carboxymethylcellulose,
wherein the granules bulk densities of 500 to 750 g / l, in particular from 500 to 600 g / l, and a What seraufnahme of 70 to 180 wt .-%, in particular from 80 to 130 wt .-%, having.

For a further embodiment of the granules, a calcium silicate hydrate material is granulated, which has as starting material before granulation particle sizes up to 2000 .mu.m, in particular up to 1000 .mu.m, and a Gaussian particle size distribution, ie consists both of flour fractions and of granular fractions of the calcium silicate hydrate material , The particle size distribution of such a product is exemplified in 1 displayed.

there lies the grainy Proportion with grain sizes between 1000 μm and 5000 μm expediently under 80 wt .-%, preferably below 10 wt .-%, in particular below 8 wt .-%.

The Starting calcium silicate hydrate products have the same water contents like the calcium silicate hydrate flour products described above. Likewise, the same amounts of water used for granulation.

The produced granules have grain sizes between 0.3 and 10 mm, in particular between 0.5 and 8.0 mm, and water contents between 20 and 45 wt .-%, in particular between 32 and 40 wt .-%. The granules is taken from the mixer and preferably dried until e.g. Water contents between 2 and 15 wt .-%, in particular between 3 and 8% by weight. These granules have bulk densities between 450 and 750 g / l, in particular between 500 and 600 g / l, on. The granules according to the invention contain in their grain structure cemented together flour particles of the calcium silicate hydrate product.

The Space shape of these granules is well rounded despite the case of the Use of granular Cellular concrete or foam concrete starting calcium silicate hydrate material irregular rugged surface structure, in the pore fragments of the macropores are still present. The granules This granules are made according to the starting material the calcium silicate hydrate product particles of different sizes.

The The composition of the granules is in the composition range given above for the flours in terms of the components calcium silicate hydrate, water after drying and Carboxymethylcellulose. These granules can be the additives listed above contain.

For a third particularly preferred embodiment of the granules is intended to use a calcium silicate hydrate material mixture with a so-called default grain, ie, to mix a calcium silicate hydrate material flour with a granular calcium silicate hydrate material, wherein grain fractions between the two products are missing or only in minor amounts for example, below 10 wt .-%, preferably below 5 wt .-%, are present. By way of example, such a composition is described in 2 shown. 2 shows the grain distribution of a flour (rhombic points) and the grain distribution of a granular product (square dots), each of cellular concrete waste material. The two grain distribution curves intersect at grain sizes between 1 and 2 mm. The grits in the range of 2 to 0.5 mm are each less than 10 wt .-% and fall under the term "default grain", as it should be understood in the invention.

In this respect, calcium silicate hydrate material flours with particle sizes below 1000 μm, in particular below 500 μm, in particular with particle size distribution maxima below 500 μm, are mixed with granular calcium silicate hydrate material grain fractions which have the following grain distributions:
> 7 mm: up to 10% by weight,
5 to 7 mm: 10 to 30 wt.%,
4 to 5 mm: 25 to 40% by weight,
3.15 to 4 mm: 25 to 40% by weight,
1 to 3.15 mm: 25 to 40% by weight,
<1 mm: to 10% by weight,
especially
> 7 mm: up to 7 wt.%
5 to 7 mm: 10 to 24% by weight,
4 to 5 mm: 27 to 34% by weight,
3.15 to 4 mm: 27 to 34% by weight,
1 to 3.15 mm: 27 to 34 wt.%,
<1 mm: to 4 wt .-%.

The Grain distribution maximum is e.g. between 2.5 and 4 mm.

The mixing ratios of flour fraction to granular grain fraction is, for example:
Flour fraction to grain fraction = 3 to 1 wt .-% to 2 to 3, in particular 2 to 1 wt .-%.

Especially advantageous in this embodiment The invention is that granules with high strength achievable are whose surface structure also have rounded contours and fewer fissures, because the Pore fragments of macropores largely covered by the flour fractions are. To ensure that these granules have particularly high water absorption capacities. The Granules correspond in composition to the composition, the above for the products made from the flours are indicated. The granules this embodiment can Furthermore also contain the specified additives and additives. she are preferably also post-granulated with cellulose ether.

The Invention succeeds when flour fractions with grain sizes below 1000 μm, in particular below 500 μm, used or co-used. The invention does not succeed with the required quality of Granules when flour fractions are missing or only in amounts below 20 % By weight are present and only grainy Calcium silicate hydrate materials in the particle size range of 1000 to 8000 microns, in particular of 1500 to 5000 μm, be granulated. If finer flours are used, shifts this limit of the flour compositions even under 20 wt .-%.

To a particular variant of this embodiment of the invention first the flour fractions in a granulating mixer with water e.g. in already entered quantities of 15 to 50, in particular of 20 to 30 wt .-% mixed to a slurry. Only then will the grainy fractions added. The resulting granules are more surprising Way a better water absorption capacity and higher abrasion resistance and better Rounding up.

It has been shown that larger granules lower Meal grains contain as smaller.

Claims (16)

Mineral granules, in particular animal granules, bulk pellets in construction, oil and / or Chemical binder granules, essentially of agglomerated, at least microporous, preferably Having micropores and macroporous calcium silicate hydrate granules Granules with a bulk density according to DIN EN 1097-3: 1998, less than 750 g / l and a proportion of flour meal in each granule with particle sizes below 1000 μm, in particular below 500 μm, between 30 and 100% by weight, in particular between 40 and 100% by weight, based on the dry matter of the granules, in particular size Granules contain proportionally lower levels of flour meal than smaller ones. Granules according to claim 1, characterized the calcium silicate hydrate material is microporous with pore diameters <100 μm and macroporous with pore diameters greater than 500 μm. Granules according to claim 2, characterized that the calcium silicate hydrate material from autoclaved aerated and / or Foamed concrete material consists. Granules according to one or more of claims 1 to 3, characterized in that the calcium silicate hydrate material is a flour is and with flour grain sizes <1200 .mu.m, in particular <1000 microns, is present. Granules according to one or more of claims 1 to 4, characterized in that the calcium silicate hydrate material both with Flour fraction grain sizes as also with grainy ones Grain fractions up to 9 mm, in particular up to 7 mm, and Gaussian particle size distribution is present. Granules according to claim 5, characterized that a flour fraction and a granular fraction with each a distinguishable Gaussian Grain distribution due to a Ausfallkörnung present. Granules according to claim 6, characterized that between the fractions a default grain or grit gap exist is by putting between the Gaussian Grain distribution curves a grit gap exists. Granules according to claim 6, characterized that the Gaussian Partial overlap of grain distribution curves (bell curves). Granules according to one or more of claims 1 to 8, characterized by bulk weights between 450 and 750 g / l, in particular between 500 and 700 g / l. Granules according to one or more of claims 1 to 9, characterized by a water absorption capacity between 70 and 180 wt .-%, in particular 80 and 130 wt .-%. Granules according to one or more of claims 1 to 10, characterized by particle sizes of Granules between 0.5 and 10.0 mm, in particular between 0.5 and 8.0 mm. Granules according to one or more of claims 1 to 11, characterized in that the granules in particular to Residual dust binding Carboxylmethylcellulose, preferably in amounts from 0.1 to 2.0% by weight, in particular from 0.2 to 1.0% by weight, or 3 to 10 wt .-% for clumping and residual dust binding. Granules according to one or more of claims 1 to 12, prepared by adding a calcium silicate hydrate material flour and optionally granular calcium silicate hydrate material in a pellet mixer during mixing with water or the flour fractions premixed with water and then the granular material was added and granules have been produced by granulating the granules taken from the pellet mixer and dried. Granules according to claim 13, characterized in that a remixing carried out and while carboxylmethylcellulose for residual dust binding, preferably in amounts of 0.1 to 1.0 wt .-%, based on the mixture, or for lumping and residual dust binding 3 to 10 wt .-% was added. Granules according to claim 13 and / or 14, characterized that grainy starting calcium silicate hydrate products to be mixed with the flour having the following Grain distribution have been used: > 7 mm: up to 10% by weight, 5 to 7 mm: 10 to 30% by weight, 4 to 5 mm: 10 to 40% by weight, 3,15 to 4 mm: 10 to 40% by weight, 1 to 3.5 mm: 10 to 60 wt.%, <1 mm: to 10% by weight Granules according to one or more of claims 13 to 15, characterized in that the following mixing ratios from flour fraction to more granular Grain fraction have been used: Flour fraction: grain fraction = 3: 1 to 2: 3, in particular up to 2: 1 wt .-%.