WO1995033684A1 - Granulated, water-soluble, silicic-acid-containing alkaline silicate - Google Patents

Abstract

A granulated amorphous silicic-acid-containing alkaline silicate has an apparent density in a range from 500 to 1200 g/l and its 1 % by weight aqueous solution has a Klett coefficient in a range from 6 to 100. Also disclosed is a process for producing this granulated alkaline silicate in a turbo-dryer by using a CO2-containing gas as drying gas, and its use as builder component in washing and cleaning agents.

Description

 "Granular water-soluble silicic acid-containing alkali silicate"

The invention relates to a granulated, water-soluble, silicic acid-containing alkali silicate with a bulk density in the range between 500 and 1200 g / l, the aqueous solution of which has an adjustable turbidity, and a process for its preparation. It is particularly suitable as a builder for detergents and cleaning agents.

As is known, hydrated water-soluble silicates can be obtained in powder form by spray or roller drying of water glass solutions and still contain about 20% by weight of water. (Compare Ullmann's Encyclopedia of Technical Chemistry, 4th edition 1982, Volume 21, page 412). Such products are commercially available for various purposes.

In the manufacture of the powdered water glasses by spray drying, heating is usually carried out directly with flame gases for reasons of cost. The CO 2 content of the flame gases leads to the silicate being partially released from the silicate. The products obtained in this way are therefore not clearly water-soluble, but form more or less cloudy solutions. The so-called Klett number can be used, for example, as a measure of the cloudiness of the solution (see Ullmanns Enzyclopadie der Technische Chemie, 4th edition 1982, volume 22, page 504). The principle of determination of the Klett number is based on the fact that the extinction of light as it passes through the solution of the test substance is measured photometrically directly. For a 1% solution of filtered and spray-dried water glass in the presence of more than 0.05% by volume of CO2, Velcro numbers in the range of approximately 9 are found. Such products are not suitable for use as builders in detergents because they lead to incrustations of the tissue. Another disadvantage of spray-dried sodium silicates (soda-water glasses) is that the powders are spray dried. have a very loose structure. Bulk weights are in the range of well below 700 g / 1. In order to save packaging, for example for compact detergents, bulk weights in the order of 700 to 1,200 g / l are desirable.

Alkali metal silicate granules with such bulk densities can be obtained, as described in EP-A-526978, by introducing an alkali metal silicate solution with a solids content between 30 and 53% by weight into a heated drum, one in the longitudinal axis Shaft rotates with a plurality of arms close to the inner surface of the drum, the drum wall having a temperature between 150 and 200 ° C and the drying process is supported by a gas fed into the drum with a temperature between 175 and about 250 ° C. This process gives a product whose average particle size is in the range between 0.2 and 2 mm. Heated air is preferably used as the drying gas. In the document mentioned it is emphasized that although the choice of drying gas is not critical, it must not react with the silicate solution. This restriction excludes, for example, the use of carbon dioxide in the drying gas, since this reacts with the silicate solution to release silica.

A similar process is described in EP-A-542131, whereby a product which is completely soluble in water at room temperature and has a bulk density of between 500 and 1,200 g / l is obtained. Drying is also preferably carried out using heated air. Here too, a cylindrical dryer with a heated wall (160 to 200 ° C.) is used, in the longitudinal axis of which a rotor with scoop-shaped blades rotates at such a speed that a from the silicate solution with a solids content of between 40 and 60% by weight pseudoplastic mass with a free water content between 5 and 12 wt .-% arises. Drying is supported by a hot air stream (220 to 260 ° C). The document also describes preferred embodiments for the entry and exit of the product. The two last-mentioned patent applications accordingly teach the production of a solid soda-water glass in the desired range of the bulk density. In their preferred embodiments they work with heated air and, according to EP-A-526978, exclude the use of gases such as CO2 which react chemically with the silicate solution. The use of CO2 is also implicitly excluded in EP-A-542 131, since a "completely soluble" product is to be produced. However, CO2 would lead to the formation of insoluble silica.

It is accordingly known to the person skilled in the art that water glasses dried in the spray tower using CO 2 -containing gases give cloudy solutions as a result of the formation of silicic acid and that such water glasses are not suitable as detergent builders since they lead to high tissue incrustation. Furthermore, from EP-A-526978 and EP-A-542 131, the person skilled in the art receives the teaching to use the drum drying processes described there for the production of silicate granules suitable as detergent component, but the drying gases used must not react with the water glass solution. Accordingly, he is advised not to use gases containing CO 2 * in these drying units, since these react with the separation of silica. The present invention overrides this teaching as follows:

The object of the invention is to provide water-soluble amorphous alkali metal silicates which have a high bulk density and whose aqueous solution is clearly clouded by the presence of dispersed, finely divided silica. The finely divided silica is expected to serve as a crystal seed for the growth of silicate precipitates (Ca and Mg silicates) and thereby to help reduce the incrustation of fibers when washing fabrics.

The invention describes a granulated amorphous alkali metal silicate with a molar ratio SiO 2: M2O (M = alkali metal) between 1.6: 1 and 3.4: 1 and a bulk density in the range 500 and 1200 g / 1, characterized in that its 1% by weight aqueous solution has a Velcro number in the range between 6 and 100, preferably 10-40. Such products are particularly suitable for use in detergents and cleaning agents: in which at least 60% by weight of the silicate particles have a particle size between 0.1 and 1.6 mm. Preferred bulk density values are between 700 and 1100 g / l.

The term "amorphous" means "X-ray amorphous". This means that the alkali metal silicates do not provide sharp reflections in X-ray diffraction images, but at most one or more broad maxima, the width of which is several degree units of the diffraction angle. However, this does not rule out the possibility that areas are found in electron diffraction experiments which give sharp electron diffraction reflections. This is to be interpreted in such a way that the substance has microcrystalline areas in a range of up to approximately 20 nm (max. 50 nm).

Sodium and / or potassium silicates are particularly suitable as alkali metal silicates. Sodium silicates are preferred for economic reasons. If, however, importance is attached to particularly rapid water solubility for reasons of application technology, it is advisable to at least partially replace sodium with potassium. For example, the composition of the alkali metal silicate can be chosen so that the silicate has a potassium content, calculated as K2O, of up to 5% by weight.

Furthermore, the invention relates to a process for the production of granulated alkali metal silicate with a SiO 2 • 2O molar ratio between 1.6: 1 and 3.4: 1 and a bulk density in the range from 500 to 1200 g / 1, the 1% by weight of which aqueous solution has a Klett number in the range between 6 and 100, preferably 10-40, characterized in that a water glass solution with a corresponding molar ratio SiO 2: M2O in a drum with a wall heated to a temperature between 150 and 250 ° C in the presence introduces a gas mixture brought to 200 to 400 ° C, which contains between 0.05 and 10 vol% CO2, and by means of a in the drum with a peripheral speed between 15 and 25 m / sec. rotating shaft coaxial to the drum accelerated against the drum inner wall. The aggregates described in EP-A-526978 and EP-A-542131 are particularly suitable for this. The solids content of the water glass solution fed into the drying unit is to be chosen so that a tough plastic stage of the alkali metal silicate is passed through during drying, whereby the desired high bulk density and the desired grain spectrum can be achieved. For example, solids contents of between 30 and 75% by weight of the water glass solution fed in are suitable. Advantageously, the process can also be carried out in two stages, with a less concentrated water glass solution, for example with a solids content of between 30 and 55% by weight, being fed in for preconcentration in the first stage and wall and gas temperature of the drying day for rapid evaporation of water ¬ sets gregates high, for example the wall temperature in the range between 200 and 250 ° C and the gas temperature in the range 300 to 400 ° C. The pre-concentrated, pasty but still flowable silicate solution, which may have a solids content of between 55 and 75% by weight, for example, is fed into a second drying unit operated at lower temperatures. In this second stage, the wall temperature of the drying unit can be, for example, between 150 and 200 ° C, and that of the gas between 200 and 300 ° C. This two-stage procedure enables a high product throughput, while at the same time the risk of local puffing up and caking of the material to be dried is kept low.

The flue gas obtainable from the combustion of fossil fuels or synthetic or biogenic carbon-containing fuels with oxygen-containing gas, preferably with air, can be used as the gas mixture. Gas mixtures whose CO 2 * content is between 1 and 5% by volume are particularly suitable as the drying medium.

The higher the CO 2 * content of the drying gas is set, the more silica-rich drying products are obtained, the 1% aqueous solution of which then has a correspondingly high Velcro number. Velcro numbers in the range from 10 to 40 are preferred, since they lead to particularly low silicate deposits when trying to deposit on a heating element. As an explanation for this, it can be assumed that the silica particles present in close association with the silicate matrix act as crystallization agents for the growth of insoluble magnesium and calcium silicates from the Water hardness formers. When such products are used as a builder component in detergents and cleaning agents, this reduces the tendency to form incrustations. The products according to the invention accordingly have a much better secondary washing power than analogous silica-free products according to the prior art, without the primary washing power being adversely affected. It has been found to be essential that the silica particles are embedded in the silicate matrix in the products according to the invention, so that they are available as nuclei at the moment of dissolution of the silicate matrix, that is to say at places of high silicate concentration. Similar incrustation-inhibiting effects are in fact not observed when a clear water-soluble alkali metal silicate is mixed with silica obtained by precipitation or pyrogenic.

When the product is dried to a water content below 15% by weight, for example to contents in the range from 5 to 15% by weight, particularly favorable secondary washing results are possible.

Finally, the invention relates to the use of the alkali metal silicates according to the invention, which are obtainable in the ways described above, as corrosion protection and / or builder components in detergents and / or washing processes for textile washing, in machine dishwashing detergents and / or cleaners for hard surfaces. The anti-corrosive action of the agents according to the invention manifests itself particularly in relation to metallic surfaces. The use according to the invention takes place in the presence of further components required for washing and cleaning purposes. Such components include, in particular, surface-active substances such as nonionic and / or anionic surfactants of fat and / or oliochemical origin, and, depending on the application, further auxiliaries such as bleaching agents, protein and / or starch-splitting enzymes, optical brighteners, complexing agents , further builder components such as phosphates and optionally further components known to the person skilled in the art.

The alkali metal silicates according to the invention are preferably used in such a way that a solid mixed product / cogranulate is produced which contains, in addition to the alkali metal silicates according to the invention, individual or mixtures of further active and auxiliary components. The ready-to-use washing or cleaning liquor is created by dissolving this solid mixed product in water. Of course, the agents according to the invention can also be used as so-called modular components by adding them separately from the other active ingredients and auxiliaries to the washing or cleaning solution.

If desired, the alkali metal silicates according to the invention can also be loaded with other liquid or easily meltable detergent ingredients, preferably nonionic surfactants, for use as components in detergents and cleaning agents.

In the following, information on mixture components that can be used in conjunction with the alkali metal silicates according to the invention is given without any claim to completeness. Basically, the entire area of valuable and auxiliary materials from the field of washing and cleaning agents is available. In particular, there are surfactants of anionic, nonionic, cationic, amphoteric and / or zwitterionic structure as well as further inorganic and / or organic builder substances, bleaching agents and bleach activators, enzymes and enzyme stabilizers, foam inhibitors, optical brighteners, inorganic alkaline and / or salts which react neutral in water, for example sulfates or chlorides, and colorants and fragrances.

Preferred surfactants of the sulfonate type are the known C9-C13-alkylbenzenesulfonates, olefin sulfonates and alkanesulfonates. Esters of oc-sulfofatty acids or the disalts of α-sulfofatty acids are also suitable. Other suitable anionic surfactants are sulfonated fatty acid glycerol esters, which are mono-, di- and triesters and their mixtures, such as those produced by esterification by a monoglycerol with 1 to 3 moles of fatty acid or in the transesterification of triglycerides with 0.3 to 2 moles of glycerol be preserved.

Suitable surfactants of the sulfate type are the sulfuric acid monoesters from primary alcohols of natural and synthetic origin, in particular from - 8 - fatty alcohols, e.g. from coconut fatty alcohol, tallow fatty alcohol, oleyl alcohol,

Lauryl, myristyl, cetyl or stearyl alcohol, or C jo-C2θ-O caves ^OA1 Ro¬ and those of secondary alcohols of this chain length. Also, the Schwefelsäuremonoester the ethoxylated with 1 to 6 moles of ethylene Al¬ alcohols such as 2-methyl-branched Cg-C _j i-alcohols having an average of 2 or 3.5 moles of ethylene oxide are suitable.

Preferred anionic surfactant mixtures contain combinations of alk (en) yl sulfates, in particular mixtures of saturated and unsaturated fatty alcohol sulfates, and alkylbenzenesulfonates, sulfated fatty acid glycerol esters and / or α-sulfofatty acid esters and / or alkyl sulfosuccinates. Mixtures are particularly preferred which contain alk (en) yl sulfates and alkylbenzenesulfonates and optionally methyl oc-sulfofatty acid and / or sulfated fatty acid glycerol esters as anionic surfactants.

Other suitable anionic surfactants are, in particular, soaps, preferably in amounts below 5% by weight. Saturated fatty acid soaps are suitable, such as the salts of lauric acid, myristic acid, pal itic acid or stearic acid, and in particular from natural fatty acids, e.g. Coconut, palm kernel or tallow fatty acids, derived soap mixtures. Unsaturated fatty acid soaps, which are derived, for example, from oleic acid, may also be present, but their proportion of the soaps should not exceed 50% by weight.

The anionic surfactants and soaps can be present in the form of their sodium, potassium or ammonium salts and as soluble salts of organic bases, such as mono-, di- or triethanolamine. The anionic surfactants are preferably in the form of their sodium or potassium salts, in particular in the form of the sodium salts. The content of anionic surfactants in the compositions is generally between 5 and 40% by weight.

The nonionic surfactants used are preferably alkoxylated, advantageously ethoxylated, in particular primary alcohols having preferably 8 to 18 carbon atoms and an average of 1 to 12 moles of ethylene oxide (E0) per mole of alcohol in which the alcohol radical has a methyl or linear branching, preferably in the 2-position can be or linear and methyl branched radicals can contain in the mixture, as they are usually present in oxo alcohol residues. However, alcohol ethoxylates with linear residues of alcohols of native origin with 12 to 18 carbon atoms, for example from coconut, palm, tallow or oleyl alcohol, and an average of 2 to 8 EO per mole of alcohol are particularly preferred. The preferred ethoxylated alcohols include, for example, Ci2-i4 alcohols with 3 EO or 4 EO, Cg-Cn alcohol with 7 EO, Ci3-Cj5 alcohols with 3 EO, 5 EO, 7 EO or 8 EO, Ci2-Ci8- Alcohols with 3 EO, 5 EO or 7 EO and mixtures of these, such as mixtures of C12-Cj4 alcohol with 3 EO and Ci2-Ci8-Al ohol with 5 EO. The degrees of ethoxylation given represent statistical averages, which can be an integer or a fraction for a specific product. Preferred alcohol ethoxylates have a narrow homolog distribution (narrow range ethoxylates, NRE). In addition to these nonionic surfactants, fatty alcohols with more than 12 EO can also be used. Examples of this are tallow fatty alcohol with 14 EO, 25 EO, 30 EO or 40 EO.

In addition, alkyl glycosides of the general formula R0 (G) _x can also be used as further nonionic surfactants, in which R is a primary straight-chain or methyl-branched aliphatic radical with 8 to 22, preferably 12 to 18, C. -Atoms means and G is the symbol which stands for a glycose unit with 5 or 6 carbon atoms, preferably for glucose. The degree of oligomerization x, which indicates the distribution of monoglycosides and oligoglycosides, is any number between 1 and 10; x is preferably 1.2 to 1.4. Other suitable surfactants are polyhydroxy fatty acid of the formula (II),

R3

I.

R ² -C0-N- [Z] (II)

in which R ^{2 is} C0 for an aliphatic acyl radical with 6 to 22 carbon atoms, R3 for hydrogen, an alkyl or hydroxyalkyl radical with 1 to 4 carbon atoms and [Z] for a linear or branched polyhydroxyalkyl radical with 3 to 10 carbon atoms and 3 is up to 10 hydroxyl groups. The proportion of nonionic surfactants in the compositions is generally 2 to 25% by weight.

All previous builder substances conventionally used can be used as further inorganic builder substances. These include, in particular, zeolites, crystalline layered silicates, even phosphates, if their use should not be avoided for ecological reasons. Their content can vary within a wide range depending on the content of the alkali metal silicates according to the invention. The sum of customary builder substances and the silicates according to the invention is usually 10 to 60% by weight.

Usable organic builders are, for example, the polycarboxylic acids preferably used in the form of their sodium salts, such as citric acid, adipic acid, succinic acid, glutaric acid, tartaric acid, sugar acids, aminocarboxylic acids, nitrilotriacetic acid (NTA), provided that such use is not objectionable for ecological reasons. and mixtures of these. Preferred salts are the salts of polycarboxylic acids such as citric acid, adipic acid, succinic acid, glutaric acid, tartaric acid, sugar acids and mixtures of these.

Suitable polymeric polycarboxylates are, for example, the sodium salts of polyacrylic acid or polymethacrylic acid, for example those with a relative molecular weight of 800 to 200,000 (based on acid). Suitable copolymeric polycarboxylates are, in particular, those of aerylic acid with methacrylic acid and of acrylic acid or methacrylic acid with maleic acid. Copolymers of acrylic acid with maleic acid which contain 50 to 90% by weight of acrylic acid and 50 to 10% by weight of maleic acid have proven to be particularly suitable. Their relative molecular weight, based on free acids, is generally 5,000 to 200,000, preferably 10,000 to 120,000 and in particular 50,000 to 100,000. Biodegradable terpolymers are also particularly preferred, for example those which, as monomers, contain salts of acrylic acid and maleic acid and vinyl alcohol or Contain vinyl alcohol derivatives (P 43 00 772.4) or the salts of acrylic acid and 2-alkylallylsulfonic acid as monomers and sugar derivatives (P 4221 381.9). Other suitable builder systems are oxidation products of carboxyl-containing polyglucosans and / or their water-soluble ones

Salts such as those used in the international patent application

W0-A-93/08251 are described or their production is described, for example, in international patent application WO-A-93/16110 or the older German patent application P 43 30 393.0.

In addition, the agents can also contain components which have a positive influence on the oil and fat washability from textiles. This effect is particularly evident when a textile is soiled that has already been washed several times beforehand with a detergent according to the invention which contains this oil and fat-dissolving component. The preferred oil- and fat-dissolving components include, for example, nonionic cellulose ethers such as methyl hydroxypropyl cellulose with a proportion of methoxyl groups of 15 to 30% by weight and of hydroxypropoxyl groups of 1 to 15% by weight, based in each case the nonionic cellulose ether, and the polymers of phthalic acid and / or terephthalic acid or known from the prior art. of their derivatives, in particular polymers of ethylene terephthalates and / or polyethylene glycol terephthalates.

In addition to the silicates, the agents can also contain other water-soluble inorganic salts such as bicarbonates and carbonates, preferably in their alkali metal salt form. The content of sodium carbonate in the compositions can be, for example, up to about 20% by weight, preferably between 5 and 15% by weight, and is in the range from 20% by weight of the silicates according to the invention, in particular to about 10% by weight. According to the teaching of the older German patent application P 43 19 578.4, alkali arbonates can also be replaced by sulfur-free, 2 to 11 carbon atoms and, if appropriate, an amino acid and / or salts thereof having a further carboxyl and / or amino group. In the context of this invention, it is preferred that the alkali metal arbonates be partially or completely replaced by glycine or glycinate.

Among the compounds which serve as bleaching agents and deliver H2O2 in water, sodium perborate tetrahydrate and Sodium perborate monohydrate of particular importance. Further usable bleaching agents are, for example, sodium percarbonate, peroxypyrophosphates, citrate perhydrates and H2O2-providing peracidic salts or peracids, such as perbenzoates, peroxophthalates, diperazelaic acid or diperdodecanedioic acid. The bleaching agent content of the agents is preferably 5 to 25% by weight and in particular 10 to 20% by weight, advantageously using boron monohydrate.

In order to achieve an improved bleaching effect when washing at temperatures of 60 ° C and below, bleach activators can be incorporated into the preparations. Examples of this are N-acyl or O-acyl compounds which form organic peracids with H2O2, preferably N, N'-tetraacylated diamines, furthermore carboxylic acid anhydrides and esters of polyols such as glucose pentaacetate. Further known bleach activators are acetylated mixtures of sorbitol and mannitol, as are described, for example, in European patent application EP-A-0525239. The bleach activators contain bleach activators in the usual range, preferably between 1 and 10% by weight and in particular between 3 and 8% by weight. Particularly preferred bleach activators are N, N, N ', N'-tetraacetylethylenediamine (TAED), 1,5-diacetyl-2,4-dioxo-hexahydro-1,5,5-triazine (DADHT) and acetylated sorbitol-mannitol mixtures (SORMAN).

When used in machine washing processes, it can be advantageous to add conventional foam inhibitors to the agents. Suitable foam inhibitors are, for example, soaps of natural or synthetic origin, which have a high proportion of Cιg-C24 * fatty acids. Suitable non-surfactant-like foam inhibitors are, for example, organopolysiloxanes and their mixtures with microfine, optionally silanized silica, and paraffins, waxes, microcrystalline waxes and their mixtures with silanized silica or bistearylethylenediamide. Mixtures of various foam inhibitors are also used with advantages, for example those of silicones, paraffins or waxes. The foam inhibitors, in particular silicone or paraffin-containing foam inhibitors, are preferably bound to a granular, water-soluble or dispersible carrier substance. Mixtures of paraffins and bistearylethylenediaids are particularly preferred.

Suitable enzymes are those from the class of proteases, lipases, amylases, cellulases or mixtures thereof. Enzymatic active ingredients obtained from bacterial strains or fungi such as Bacillus subtilis, Bacillus licheniformis and Streptomyces griseus are particularly suitable. Proteases of the subtilisin type and in particular proteases which are obtained from Bacillus lentus are preferably used. Enzyme mixtures, for example of protease and amylase or protease and lipase or protease and cellulase or of cellulase and lipase or of protease, amylase and lipase or protease, lipase and cellulase, but in particular mixtures containing cellulase, are of particular interest. Peroxides or oxidases have also proven to be suitable in some cases. The enzymes can be adsorbed on carriers and / or embedded in coating substances in order to protect them against premature decomposition. The proportion of the enzymes, enzyme mixtures or enzyme granules can be, for example, about 0.1 to 5% by weight, preferably 0.1 to about 2% by weight.

The salts of polyphosphonic acids, in particular l-hydroxyethane-l, l-diphosphonic acid (HEDP), diethylenetriaminepentamethylenephosphonic acid (DETPMP) or ethylenediaminetetramethylenephosphonic acid (EDTMP) are suitable as stabilizers, in particular for per compounds and enzymes.

Graying inhibitors have the task of keeping the dirt detached from the fiber suspended in the liquor and thus preventing graying. Water-soluble colloids of mostly organic nature are suitable for this, for example the water-soluble salts of polymeric carboxylic acids, glue, gelatin, salts of ether carboxylic acids or ether sulfonic acids of starch or cellulose or salts of acidic sulfuric acid esters of cellulose or starch. Water-soluble polyamides containing acidic groups are also suitable for this purpose. Soluble starch preparations and starch products other than those mentioned above can also be used, for example degraded starch, aldehyde starches, etc. Polyvinylpyrrolidone can also be used. However, cellulose ethers such as carboxyethyl cellulose (Na salt), methyl cellulose, hydroxyalkyl cellulose and mixed ethers such as Methylhydroxyethylcellulose, methylhydroxypropylcellulose, methylcarboxymethylcellulose and mixtures thereof, and also polyvinylpyrrolidone, for example in amounts of 0.1 to 5% by weight, based on the composition.

As optical brighteners, the agents can contain derivatives of diaminostilbenedisulfonic acid or its alkali metal salts. Suitable are e.g. Salts of 4,4'-bis (2-anilino-4-morpholino-l, 3,5-triazinyl-6-amino) stilbene-2,2'-disulfonic acid or similar compounds, instead of morpholino Group carry a diethanolamino group, a methylamino group, an anilino group or a 2-methoxyethylamino group. Brighteners of the substituted diphenylstyryl type may also be present, e.g. the alkali salts of 4,4'-bis (2-sulfostyryl) diphenyl, 4,4'-bis (4-chloro-3-sulfostyryl) diphenyl, or 4- (4-chlorostyryl) -4 '- (2- sulfostyryl) diphenyls. Mixtures of the aforementioned brighteners can also be used.

The bulk density of the preferred granular washing or cleaning agents which contain the silicates according to the invention is generally 300 to 1200 g / 1, but preferably 500 to 1100 g / 1. Washing and cleaning agents with bulk densities of at least 700 g / l are very particularly preferred. They can be prepared by any of the known processes, such as mixing, spray drying, granulating and extruding, the silicates or cogranulates of the silicates according to the invention advantageously being processed or mixed with the other components of the composition with further valuable substances. In granulation and extrusion processes in particular, it is preferred to use the anionic surfactants, if any, in the form of a spray-dried, granulated or extruded compound, either as an additive component in the processes mentioned or as an additive to other granules. It is also possible and, depending on the recipe, to be advantageous if further individual constituents of the agent, for example carbonates, citrate or citric acid or other polycarboxylates or polycarboxylic acids, polymeric polycarboxylates, zeolite and / or layered silicates, for example layered ones Crystalline disiliates are subsequently mixed into spray-dried, granulated and / or extruded components. Execution examples

A drying unit of the type described above (see EP-A-526978 and EP-A-542131) was used for the production of the products. Such units are sold, for example, by VOMM Impianti e Proessi, Via Liberta 34, 1-20090 Cesano Boscone (Milano), Italy.

Na-58/60 (Henkel KGaA, Dusseldorf) with a solids content of 54.5% by weight after depth filtration through a plate filter with filter aid was used as the sodium water glass solution. More detailed information about the experimental conditions and properties of the products obtained are summarized in Table 1.

The grain size distribution was determined by sieve analysis. The Klett number was measured using the method cited at the beginning with light of the wavelength. 400 - 460 nm with a measuring device from Klett Manufacturing Co. Inc., New York. 1% by weight solutions were used as sample solutions. For comparison, the Klett number of a 1% by weight solution of a product conventionally dried in a spray tower using flue gas (CO 2 content 3.6% by volume) was determined (Porti1 A, Henkel KGaA, Dusseldorf): It was 9. The water content was determined by the weight loss when heated to 800 ° C. for three hours.

For a 1% solution of the product from Example 1, the particle size distribution was examined using a laser diffraction spectrometer (from Helos). Thereafter, 80% of the particles were in the size range 2 to 33 μm, each 10% below or above these limits.

Table 1: Manufacturing conditions and substance parameters

Cf. Ex. 1 Ex. 2 Ex. 3 Ex. 4

Circumferential speed 19.5 19.5 19.5 19.5 19.5 of the rotor m / s

Jacket temperature 170 170 170 220 200 ° C

Gas temperature ° C 220 220 220 300 250

Water glass supply 220 220 220 220 150 kg / h

CO 2 content of the 0 2.2 4.0 4.0 2.2 gas (vol.%)

Bulk weight 935 908 930 720 515 product g / 1

Water content 18.6 18.4 18.2 14.5 11.8 (% by weight)

Grain size distribution

> 1.6 mm% 3.1 4.5 3.0 5.8 4.2

<0.2 mm% 46.2 47.4 44.6 45.3 46.5

<0.1 mm% 20.4 20.5 19.1 15.4 19.8

Velcro (l% 3-4 16.5 25.3 33 17 solution) Application tests

The above-mentioned products and comparative products were subjected to application tests with which the basic suitability of the products as builder substances for detergents and cleaning agents could be established. The tests are described in more detail below and their results are summarized in Table 2.

Dissolving behavior

500 mg of the sample are placed in 1 l of water at 25 ° C. The conductivity curve and the pH value are recorded in parallel. Na-SKS-6 ^R (crystalline sodium disilicate with layer structure, commercial product from Hoechst, Germany) serves as the standard. Its conductivity after 10 minutes is set as a 100% value.

Calcium binding capacity

The Ca binding capacity was determined by adding a defined amount of the sample to be examined to a Ca 2+ solution of 30 ° d, which had been adjusted to pH 10 with dilute sodium hydroxide solution. The mixture was stirred for 10 minutes at room temperature and then filtered through a membrane filter (<0.45 μm). The content of Ca ²⁺ ions in the filtrate was determined complexometrically by titration against EDTA and converted into the calcium binding capacity in mg CaO / g active substance.

Deposits on the heating element

10 1 of industrial water (hardened to 30 ° d Ca / Mg 5: 1 mixed hardness) are filled in a stainless steel vessel with a heating rod and mixed with 1.67 g of the sample to be examined. The mixture is heated to 90 ° C. within 30 minutes and kept at this temperature for a further 30 minutes. After cooling and draining the water, the experiment is repeated four more times. The deposits on the heating element are removed with alkaline citrate solution and analyzed analytically for Ca, Mg and SiÜ2.

Table 2: Results of application tests

Product rel. Solubility Calcium binding capacity Deposits on the heating element gCaO mgMgO mgSiθ2 viU 120 132 280 8 236

Compare 110 123 220 5 180

Comparison + 108 125 220 5 220

0.5% by weight PKS ³ )

Ex. 1 105 115 180 5 220

Ex. 95 110 150 4 198

Ex. 3 115 125 168 4 208

Ex. 4 120 135 105 3 20

1) VI: Porti1 ^R A: Spray-dried soda water glass with module 2 and loss on ignition (800 ° C) approx. 18%. Commercial product from Henkel, Germany

3) PKS = pyrogenic silica, Aerosil ^R 200, from Degussa, Frankfurt

Claims

Claims 1. Granulated silica-containing amorphous alkali metal silicate with a molar ratio SiO 2: MO (M = alkali metal) between 1.6: 1 and 3.4: 1 and a bulk density in the range 500 to 1200 g / 1, characterized in that its 1 wt .-% aqueous solution has a Klett number in the range between 6 and 100. 2. Granulated silicic acid-containing amorphous alkali metal silicate according to claim 1, characterized in that its 1% by weight aqueous solution has a Velcro number in the range between 10 and 40. 3. Granulated silica-containing amorphous alkali metal silicate according to one or both of claims 1 and 2, characterized in that the alkali metal is selected from sodium and potassium or mixtures thereof, with sodium silicate being preferred and this being desired - if necessary a potassium content, calculated as K2O, up to Can have 5 wt .-%. 4. Granulated amorphous alkali metal silicate containing silicic acid according to one or more of claims 1 to 3, characterized in that at least 60% by weight of the particles have a particle size between 0.1 and 1.6 mm and the bulk density preferably in the range 700 to 1100 g / 1 lies. 5. A process for the preparation of granular amor¬ phenic alkali metal silicates containing silicic acid according to one or more of claims 1 to 4, characterized in that a water glass solution with a corresponding molar ratio SiO 2: M2O in a drum with a temperature between 150 and 250 ° C heated wall in the presence of a gas mixture brought to 200 to 400 ° C, which contains between 0.05 and 10 vol% CO2, and by means of a in the drum with a peripheral speed between 15 and 25 / sec. spinning the shaft coaxial with the drum is accelerated against the inner wall of the drum, the water glass solution introduced into the drum having a solids content of 30 to 75%, preferably a solids content between 30 and 65% by weight. 6. The method according to claim 5, characterized in that it is carried out in two stages by introducing a water glass solution with a solids content of between 30 and 55% by weight into the drying unit in the first stage for preconcentration, the wall preferably having a temperature in the range 200 to 250 ° C and the gas have a temperature in the range 300 to 400 ° C and in a second stage the still flowable silicate solution with a solids content between 55 and 75 wt .-% in the drying unit, preferably the wall Temperature in the range 150 to 200 ° C and the gas have a temperature in the range 200 to 300 ° C. 7. The method according to one or both of claims 5 and 6, characterized ge indicates that the C02 * content of the gas mixture is between 1 and 5% by volume. 8. The method according to one or more of claims 5 to 7, characterized in that the gas mixture used in the combustion of fossil fuels or synthetic or biogenic carbon-containing fuels with oxygen-containing gas, preferably with air, is obtained flue gas. 9. Use of the granular silicic acid-containing amorphous alkali metal silicates according to one or more of claims 1 to 4 as a builder and / or corrosion protection component in detergents and cleaning agents. 10. Use of the products obtainable by the process according to one or more of claims 5 to 8 as a builder and / or corrosion protection component in washing and cleaning agents.