GB2029854A - A process for the production of finely agglomerated detergents - Google Patents

Abstract

A process for the production of a highly soluble, finely agglomerated detergent comprises spraying a liquid phase onto a substrate in such a quantity that it exceeds the absorption capacity of the substrate and that the sprayed-on product has a trickle test value (according to DIN 53916) of less than 1.5, and then adding at least one substantially insoluble, precipitated powder having a maximum particle size of less than 35 microns and a mean particle size of less than 10 microns in a quantity of more than 0.5%, but less than 50% of the sprayed-on product. Thus, a poorly tickling adhering product is first prepared and subsequently converted into a readily flowing product by the addition of powders having a certain particle size.

Description

SPECIFICATION A process for the production of finely agglomerated detergents The present invention relates to a process for the production of finely agglomerated detergents.

More particularly, it relates to a process for the production of a highly soluble, finely agglomerated detergent which comprises spraying a liquid phase onto a substrate in such a quantity that it exceeds the adsorption capacity of the substrate and that the sprayed-on product has a trickle test value (according to DIN 53 916) of less than 1.5, and then adding at least one substantially insoluble, precipitated powder having a maximum particle size of less than 35 microns and a mean particle size of less than 10 microns in a quantity of more than 0.5%, but less than 50% of the sprayed-on product.

Thus, a poorly trickling adhering product is first prepared and then converted into a readily flowing product by the addition of powders having a certain particle size.

It is possible to obtain finely agglomerated products by this process providing more than two thirds of the surfactant consists of anionic surfactant and/or providing more than 10% and preferably more than 25% of the liquid phase consists of an alkali metal silicate solution, in which case the content of non-ionic surfactants may amount to more than 10% and preferably to more than 25% of the total surfactant content of the detergent.

Thus, in one embodiment of the process according to the present invention, one or more surfactants in which the anionic surfactant content makes up at least two thirds of the total surfactant content, are sprayed onto the substrate, optionally together with aqueous solutions of other detergent ingredients, in such a quantity that the sprayed-on product has a trickle test value of less than 1.55 and preferably less than 1.5, but more than 1.0, after which substantially insoluble, precipitated powders having a maximum particle size of less than 35 microns and a mean particle size of less than 10 microns are added in a quantity of from 0.5 to 10%, preferably in a quantity of from 2 to 7%.

In this embodiment, at least two thirds of the surfactant consists of anionic surfactants on account of the considerably better binding power of anionic surfactants which, for this reason, are suitable for building up stable aggregations.

In another embodiment of the present invention, however, stable binding and finely agglomerated, soluble washing powders can also be obtained, by spraying on aqueous alkali metal silicate solutions with or without the use of anionic surfactants.

The substantially insoluble precipitated powders used may be precipitated, dried silica and/or precipitated silicates and/or neutral phosphates of polyvalent metals, particularly magnesium, calcium or aluminium. Of these powders, a zeolitic molecular sieve, such as the molecular sieve A40, is particularly suitable because it is at the same time capable of replacing part of the phosphate present in the substrate.

Where a zeolitic molecular sieve is used as a phosphate substitute, it is necessary to keep back a considerable proportion of the molecular sieve until the end of the spraying on process, subsequently to carry out the oversaturation spraying step and, finally, to add the rest of the molecular sieve.

The process of the present invention enables detergents having a high content of surfactants and also a high content of sprayed-on alkali metal silicate solution to be obtained.

The alkali metal silicate solution may be prepared by mixing commercial waterglass with alkali metal liquor. Approximately one third of the normal waterglass consists of a dry substance and has approximately 50% sodium hydroxide solution added to it, a mixing ratio corresponding to the Na disilicate generally being sought.

The silicate solution may be sprayed on at the same time as the surfactants (from separate nozzles) or successively. The various surfactants may also be sprayed on at the same time or successively, provision having to be made to ensure a good surface renewal rate of the substrate, i.e. the surface of the substrate has to be permanently kept in rapid motion.

The advantage of the non-ionic surfactant is that it can be sprayed on easily, i.e. without technical complications. Its drawback, i.e. the fact that it does not form stable aggregations, is compensated by adding silicate solution in excess and then a drying agent. The silicate solution then forms the required stable aggregations (i.e. it builds up strong irreversible bonds between the individual particles). This leads to a fine-grained end product having very good free-flow properties, whereas without the silicate the non-ionic surfactants would lead to a weak unstable structure.

The sprayed-on product should have a trickle test value of less than 1.5 Products such as these no longer flow freely, but instead "creep". The effect according to the present invention is more distinct, the lower the trickle test value of the sprayed-on product, i.e. the more tacky the product. If the trickle test value falls below 1.0, however, there is a risk that it will be impossible to make the product flow freely, even by the addition of very large quantitites of "drying agents".

Trickle Test Fluidity is measured in accordance with DIN 53 916 ("Determining the fluidity of powders and granulates: Pfrengle process"). A measure of fluidity is the co-tangent of the angle of repose which has to be worked out as stipulated in the DIN specification. The higher the trickle test value, the greater the degree of fluidity. Trickle test values above 1.65 may be regarded as very good. Trickle test values above 1.7 may readily be obtained, however, using the process according to the invention.

Theoretically, the degree of oversaturation may readily be defined as the percentage content of liquid sprayed on. This is not practicable, however, because the amount of liquid adsorbed differs appreciably according to the nature of the substrate. In the case of a heavy dense powder, barely 5% of liquid can be adsorbed whereas a highly voluminous substrate can take up as much as 25% of liquid. Accordingly, the degree of oversaturation is defined by the condition of the sprayed product as determined by the trickle test.

In carrying out the process according to the present invention, however, it is also important to ensure that the oversaturation with liquid is not overdone and, in particular, does not fall below a trickle test value of 1.0. This is because, if so much liquid is sprayed on that already stable spheres are formed, the product generally cannot be converted back into a practicable powder, even by adding large quantities of drying agent.

In the case of the "drying agents", the specified diameters of the individual particles do not represent a limit beyond which the effect is not obtained. Even somewhat coarser particles still have an effect. The effect is better, however, the finer the particles. Very fine drying agents also have the advantage that they do not settle on the washing in the washing solution.

Commercial magnesium silicate has a somewhat less strong drying effect than the phosphates and silicates mentioned in the Examples. If, nevertheless, magnesium silicate is used in a few Examples, it is because of its traditional function as a perborate stabiliser.

The quantity in which the drying agent is added is governed by the degree of oversaturation. It amounts to more than 0.5% and is generally in the range of up to 10%. Larger additions of drying agent may be necessary, however, with relatively high degrees of oversaturation. Additions as large as these are primarily made where the phosphate substitute, zeolite, is used and where a high phosphate substitution is required. In cases such as these, the quantitites added may amount to more than 20%, but will not reach 50% of the sprayed-on product.

The technical advance afforded by the process according to the present invention may be summed up primarily by the following four main points: 1) It is possible to use all or some of the surfactant in the form of a non-ionic surfactant and, in spite of this, to obtain a very fine, dry, particulate, non-dusting and free-flowing product. Overall, particularly high surfactant contents may be obtained: in the Examples, they amount to as much as 23.7%.

2) A calculatory advantage: the sodium silicate, hitherto always added in solid form, may be replaced by the far less expensive sodium silicate solution. Hitherto, it was not possible to spray on silicate solution because the sprayed-on surfactant did not leave enough adsorption surface over on the substrate. It is now possible to spray on both the surfactant and also the silicate.

3) Another calculatory advantage: it is possible to achieve high sprayed-on water contents with which the fillers hitherto used in the formulation, particularly the sulphate, may be completely or partly replaced.

4) It is possible to produce a very fine washing powder having a high content of zeolitic molecular sieve which does not form any dust and consists of stable agglomerates, whereas hitherto it has only been possible, in spraymixing with a relatively high content of zeolite in the substrate, to obtain dust-forming products having poor trickle test values. This advance will mainly be of importance if detergent manufacturers are compelled by law to use a considerably lower phosphate content and to replace the missing phosphate by zeolite.

The present invention is illustrated by the following Examples.

Example 1 In a double-conical spray-mixing drum according to German Patent No. 1,197,064, sodium triphosphate (powder density 250 g/l) is mixed with sodium sulphate (powder density 500 g/l), CMC, enzyme and optical lightener. Using a three-passage mixing and spraying nozzle, the resulting mixture is mixed and sprayed first with tallow fatty acid and sodium hydroxide and then with concentrated alkyl benzene sulphonic acid and sodium hydroxide. Finally, non-ionic surfactant (PLURONIC D 25) is sprayed on together with a little water from a two-passage nozzle. The perfume was contained in the non-ionic surfactant.

The resulting product has a trickle test value of 1.31.

Precipitated calcium silicate phosphate is then added so that the overall composition is as follows: Na triphosphate 61.8% Na sulphate 14.7% CMC 1.5% Enzyme 0.9% Optical lightener 0.3% Alkyl benzene sulphonate 5.7% Soap 2.9% Non-ionic surfactant 3.4% Water 3.8% Calcium silicate phosphate 4.9% This quality preliminary detergent has a powder density of 338 g/l, a pH-value of 10.2 and a trickle test value of 1.72. The Ca silicate phosphate had a P206 content of 21.9%, an SiO2 content of 32.5% and a CaO content of 28.8%. Its powder density amounted to 260 g/l, its maximum particle size to 1 7 microns and its mean particle size to 6.1 microns. It is commercially available.

Example 2 Inexpensive detergent on a spray tower basis A preliminary product consisting of 64% of sodium sulphate, 27% of sodium triphosphate and 9% of sodium disilicate is prepared in a spray tower. The heating air enters this at a temperature of 343"C. This preliminary product had a powder density of 313 g/l.

Using the same spray-mixing drum as described in Example 1, this preliminary spray tower product is mixed with more Na triphosphate (powder density 500 g/l), Na perborate tetrahydrate, more Na disilicate, magnesium silicate (as perborate stabiliser), CMC and optical lightener. Using the same three-passage nozzle as in Example 1, the resulting mixture is mixed and sprayed first with tallow fatty acid and sodium hydroxide in an equivalent ratio and then with concentrated alkyl benzene sulphonic acid and sodium hydroxide.

Non-ionic surface (PLURONIC D 25) is then sprayed on from a two-passage nozzle.

The sprayed-on product now has a trickle test value of 1.24.

Zeolitic molecular sieve A40 and the same quantity of calcium hydroxyl apatite are then added, so that the overall composition is as follows: Na sulphate 33.1% Na triphosphate 20.1 % Na perborate tetrahydrate 17.5% Na disilicate 7.0% Mg silicate 1.9% CMC 1.0% Optical lightener 0.3% Alkyl benzene sulphonate 7.9% Soap 2.9% Non-ionic surfactant 3.1 % Perfume 0.1% Water 1.0% Molecular sieve A40 2.05% Calcium hydroxyl apatite 2.05% The preliminary spray tower product has a powder density of 404 g/l, a trickle test value of 1.68 and a pH value of 10.65.

The zeolitic molecular sieve had a mean particle size of 4.1 microns and a maximum particle size of 14 microns. The molar Na2O:Al203:SiO2-ratio amounted to 1:1:2.1 7.

The product is commercially available. Its production is described in Donald W. Breck's book entitled "Zeolite Molecular Sieves", John Wiley and Sons, New York, 1 974.

The calcium hydroxyl apatite had a CaO content of 49%, a P205 content of 41 % and a powder density of 1 50 g/l. It is commercially available. Its maximum particle size was 11 microns and its mean particle size 1.4 microns.

Example 3 Quality heavy-duty detergent In the double-conical spray-mixing drum of the preceding Examples, Na triphosphate (powder density 450 g/l) is mixed with Na perborate monohydrate, Na sulphate (powder density 500 g/l), Na disilicate, CMC, enzyme and optical lightener. Non-ionic surfactant (MARLOPHEN 814), in which the perfume was dissolved, is sprayed on from a twopassage nozzle. Tallow fatty acid and sodium hydroxide are then mixed and sprayed onto the substrate from a three-passage nozzle, concentrated alkyl benzene sulphonic acid and sodium hydroxide subsequently being mixed and sprayed on in the same way.The mixture now has a trickle test value of 1.45, i.e. it "creeps". Trialuminium phosphate is then added, so that the overall composition is as follows: Na triphosphate 40.0% Na perborate monohydrate 16.7% Na sulphate 12.0% Na disilicate 6.2% CMC 1.5% Enzyme 1.0% Optical lightener 0.3% Non-ionic surfactant 4.6% Perfume 0.1% Soap 4.1% Alkyl benzene sulphonate 8.3% Water 0.9% Trialuminium phosphate 4.3% Accordingly, the total surfactant content amounts to 17%, the trickle test value to 1.71, the pH-value to 10.2 and the powder density to 447 g/l.

The trialuminium phosphate had an Awl203 content of 32%, a P205 content of 45% and a powder density of 140 g/l. Its maximum particle size was 1 6 microns and its mean particle size 5.8 microns. The product is commercially available.

Example 4 Quality heavy-duty detergent The procedure is exactly the same as described in Example 3, except that, instead of trialuminium phosphate, the same calcium silicate phosphate as in Example 1 is added at the end.

Accordingly, the end product contained 4.3% of calcium silicate phosphate and had a pH-value of 10.2, a powder density of 469 g/l and a trickle test value of 1.78, i.e. very high.

Example 5 Hand detergent In the same double-conical spray-mixing drum, sodium triphosphate (powder density 450 g/l) is mixed with Na sulphate (powder density 500 g/l), sodium disilicate, CMC, enzyme and optical lightener. Non-ionic surfactant (MARLOPHEN 814) is sprayed on from a two-passage nozzle, after which concentrated alkyl benzene sulphonic acid and sodium hydroxide are mixed and sprayed onto the substrate using the same three-passage nozzle as in the preceding Examples. The mixture has a trickle test value of 1.44.

The zeolitic molecular sieve A40 used in Example 2 and in addition the same quantity of calcium silicate phosphate as in Example 1 are then added, so that the overall composition is as follows: Na triphosphate 44.1 % Na sulphate 21.6% Na disilicate 10.7% CMC 1.6% Enzyme 0.7% Optical lightener 0.3% Non-ionic surfactant 5.0% Perfume 0.1 % Alkyl benzene sulphonate 11.4% Water 0.5% Molecular sieve A40 2.0% Calcium silicate phosphate 2.0% This product has a trickle test value of 1.69, a pH-value of 10.2 and a powder density of 463 g/l.

Example 6 inexpensive detergent on a spray tower basis The same preliminary spray tower product as described in Example 2 is used for this Example: 64% of Na sulphate, 27% of Na triphosphate and 9% of Na disilicate; powder density 313 g/l.

Using the same double-conical spray-mixing drum as described in the preceding Examples, it is mixed with more Na triphosphate (powder density 500 g/l), Na perborate tetrahydrate, more Na disilicate, magnesium silicate (as perborate stabiliser), CMC and optical lightener. Concentrated alkyl benzene sulphonic acid and sodium hydroxide in an equivalent ratio are than mixed and sprayed on from a three-passage nozzle. Thereafter non-ionic surfactant (PLURONIC D25) is sprayed on.

The sprayed-on produced has a trickle test value of 1.29. Precipitated sodium aluminium silicate, produced as described below, is then added, so that the overall composition is as follows: Na sulphate 33.3% Na triphosphate 20.8% Na perborate tetrahydrate 17.6% Na disilicate 7.0% Mg silicate 1.9% CMC 1.0% Optical lightener 0.3% Alkyl benzene sulphonate 10.2% Non-ionic surfactant 3.1% Perfume 0.1 % Water 1.0% Na-AI-silicate 3.8% The preliminary spray tower product makes up 50% of this overall composition.

The end product has a powder density of 360 g/l, a pH-value of 10.4 and a trickle test value of 1.73. The dissolving time is 14 minutes.

The Na-Al-silicate used was prepared as follows: A dilute, strongly alkaline solution of Na aluminate is mixed while stirring (using a powerful stirrer rotating at 6730 r.p.m.) at room temperature with dilute waterglass solution. After filtration, thorough washing is continued until the washing water has a pH-value of only 10.0. The filter cake is dried at 90"C.

The product has a mean particle size of 6 microns with no particles larger than 30 microns in size. The Na2O:A1203:SiO2-ratio amounts to 1:1:3.6.

Example 7 Heavy-duty detergent containing zeolite as a phosphate substitute Molecular sieve A40 is mixed with Na triphosphate (powder density 450 g/l), Na sulphate (powder density 500 g/l), Na perborate monohydrate, Na disilicate, CMC, optical lightener and enzyme in a double-conical spray-mixing drum and the resulting mixture subsequently sprayed with non-ionic surfactant (MARLOPHEN 814). Tallow fatty acid and 50% sodium hydroxide solution are then mixed and sprayed on from a three-passage nozzle. Thereafter, concentrated alkyl benzene sulphonic acid and sodium hydroxide solution are mixed and sprayed on from the same three-passage nozzle until the highly agglomerated sprayed-on product makes a somewhat moist impression. 4% of molecular sieve A40 are then added and the whole is passed through a sieve a number of soft walnut-sized lumps being easily pushed through. The trickle test value amounts to 1.45.

Another 2% of molecular sieve A40 are then added. The trickle test value now amounts to 1.61, the pH-value to 10.2 and the powder density to 538 g/l. The dissolving time amounts to 10-1 5 minutes. The overall composition is as follows: Molecular sieve A40 21.7% Na triphosphate 19.8% Na perborate tetrahydrate 15.0% Na sulphate 10.8% Na disilicate 5.5% CMC 1.5% Enzyme 0.8% Optical lightener 0.3% Non-ionic surfactant 3.8% Soap 3.4% Alkyl benzene sulphonate 15.9% Water 1.5% The product contains 80% of particles larger than 0.4 mm and only 6% smaller than 0.15 mm, whereas known heavy-duty detergents contain from only 45 to 50% of particles larger than 0.4 mm and from 25 to 30% of particles smaller than 0.15 mm.Accordingly, the product according to the present invention is highly agglomerated and substantially dust-free. The maximum particle size is 4 mm.

Thus, it is possible by the oversaturation process to introduce a high proportion of zeolite into a detergent without any dust formation. At the same time, it has been shown that this process enables a high proportion of surfactant to be introduced into the detergent, namely 23.1%.

Example 8 heavy-duty detergent containing sprayed-on silicate in a double-conical spray-mixing drum according to German Patent No. 1,197,064, 8.25 kg of Na triphosphate (powder density 300 g/l) are mixed with 0.5 kg of molecular sieve A40, 4 kg of Na perborate monohydrate, 1.025 kg of cold-sprayed powder soap, 0.375 kg of CMC, 0.2 kg of enzyme and 0.075 kg of optical lightener. 1.1 5 kg of nonionic surfactant (MARLOPHEN 814) containing 0.025 kg of perfume are sprayed on from a two-passage nozzle. 1.605 kg of alkyl benzene sulphonic acid and 0.41 kg of 50% sodium hydroxide solution are then mixed and sprayed onto the substrate from a mixing and spraying nozzle (three-passage nozzle). Finally, a mixture of 3.5 litres of soda waterglass and 1.11 litres of sodium hydroxide is sprayed on from a two-passage nozzle.

Then a mixture of 1.6 kg of molecular sieve A40 and 1.6 kg of Na triphosphate (powder density 300 g/l) is added and the product sieved.

The fluidity of the powder is very good: trickle test value 1.75; powder density 451 g/l; pH-value 10.3. The powder is mediumgrained. Its composition is as follows: Na triphosphate 33.7% Na perborate monohydrate 16.4% Molecular sieve A40 8.6% Na disilicate 7.4% Soap 4.2% CMC 1.5% Enzyme 0.8% Optical lightener 0.3% Non-ionic surfactant with 0.1% of perfume 4.7% ABS 7.0% Water 15.2% Although the non-ionic surfactant makes up 40% of the total surfactant content, it has been possible to produce a free-flowing drygrained product which has a high content (7.4% of sprayed-on Na disilicate and, in addition, contains 15.2% of sprayed-on water.

Example 9 heavy-duty detergent and water-soluble scouring composition containing sprayed-on silicate In the same spray-mixing drum, 8.75 kg of Na triphosphate (powder density 300 g/l) are mixed with 1 kg of Na sulphate (powder density 500 g/l), 4 kg of sodium perborate monohydrate, 1 kg of molecular sieve A40, 0.375 kg of CMC and 0.2 kg of enzyme. A mixture of 3.5 litres of waterglass and 0.41 litre of sodium hydroxide is then sprayed on from a two-passage nozzle. 1.605 kg of ABS acid and 0.41 kg of sodium hydroxide are then mixed and sprayed on from a threepassage nozzle, followed by 0.901 kg of tallow fatty acid and 0.34 kg of sodium hydroxide. Finally, 1 kg of non-ionic surfactant (MARLOPHEN 810) containing 0.025 kg of perfume is sprayed on from a two-passage nozzle.

Another 3.5 litres of waterglass mixed with 0.41 litre of sodium hydroxide are then sprayed onto this product, and the resulting nonflowing, tacky sprayed-on product is mixed with 2 kg of molecular sieve A40 and sieved.

A uniformly coarse-grained product was obtained in this way: spheres 4 mm in diameter trickle test value 1.51, pH-value 10.5 and powder density 729 g/l.

Overall composition: Na triphosphate 26.9% Na perborate monohydrate 12.3% Molecular sieve A40 9.2% Na sulphate 3.1% CMC 1.1% Enzyme 0.6% Na disilicate 11.1% Water 24. 1% ABS 5.3% Soap 3.1% Non-ionic surfactant 3.1% Perfume 0.1 % This product may be used both as a heavyduty detergent and also as a cleaning and scouring composition for solid surfaces (watersoluble scouring composition).

In this case, the non-ionic surfactant makes up 27% of the total surfactant content. In spite of this, the product has a very stable, uniformly coarse particle form. It has a very high content (11.1 %) of sprayed-on disilicate and contains 24.1 % of water, in spite of which this detergent is completely dry.

Example 10 Heavy-duty detergent containing only nonionic surfactant and sprayed-on Na disilicate In order to show that very fine detergents containing only a non-ionic surfactant may also be produced by the process according to the present invention, 1 kg of molecular sieve A40 was mixed in the same spray-mixing drum with 6.25 kg of Na triphosphate, 4 kg of Na perborate monohydrate, 2 kg of Na sulphate (powder density 500 g/l), of 0.375 kg of CMC and 0.2 kg of enzyme. A mixture of 3.5 litres of waterglass and 0.41 litre of sodium hydroxide was then sprayed on from a two-passage nozzle.

Finally, 3.5 kg of non-ionic surfactant (MARLOPHEN 810) containing 0.025 kg of perfume was sprayed on. 5.45 kg of molecular sieve A40 were added to this tacky, nonflowing product, followed by sieving.

This medium-grained detergent, which has a powder density of 595 g/l, a pH-value of 10.4 and a trickle test value of 1.63, is characterised by a solid grain with good freeflow properties despite the fact that it only contains non-ionic surfactant.

Its composition is as follows: Molecular sieve A40 22.5% Na triphosphate 22.3% Na perborate monohydrate 14.3% Na sulphate 7.1% CMC 1.3% Enzyme 0.7% Na disilicate 6.4% Non-ionic surfactant with 0. 1% of perfume 12.3% Water 13.0% This washing powder which has a very good appearance and a high water content dissolves very quickly and completely in water.

Claims (14)

CLAIMS 1. A process for the production of a highly soluble, finely agglomerated detergent which comprises spraying a liquid phase onto a substrate in such a quantity that it exceeds the adsorption capacity of the substrate and that the sprayed-on product has a trickle test value (according to DIN 53 916) of less than

1.5, and then adding at least one substantially insoluble, precipitated powder having a maximum particle size of less than 35 microns and a mean particle size of less than 10 microns in a quantity of more than 0.5%, but less than 50% of the sprayed-on product.

2. A process as claimed in Claim 1, wherein one or more anionic surfactants make up more than two thirds of the total surfactant content of the detergent.

3. A process as claimed in claim 1 or 2, wherein at least 10% of the liquid phase consists of an alkali metal silicate solution.

4. A process as claimed in claim 3, wherein more than 25% of the liquid phase consists of an alkali metal silicate solution.

5. A process as claimed in any of claims 1 to 4, wherein one or more non-ionic surfactants make up more than 10% of the total surfactant content of the detergent.

6. A process as claimed in claim 5 wherein one or more non-ionic surfactants make up more than 25% of the total surfactant content of the detergent.

7. A process as claimed in any of claim 1 to 6 wherein dried silica and/or a precipitated silicate and/or a netural phosphate of at least one polyvalent metal is used as the substantially insoluble, precipitated powder.

8. A process as claimed in claim 7 wherein the polyvalent metal is magnesium, calcium or aluminium.

9. A process as claimed in claim 7 or 8 wherein a zeolite is used as the substantially insoluble precipitated powder.

10. A process as claimed in claim 9 wherein the zeolite is molecular sieve A40.

11. A process as claimed in any of claims 1 to 10, wherein some of the phosphate in the substrate is replaced by a zeolitic molecular sieve of which a considerable proportion is not added until the end of the spraying-on process.

12. A process for the production of a highly soluble, finely agglomerated detergent substantially as described with particular reference to the Examples.

1 3. A highly soluble, finely agglomerated detergent when prepared by a process as claimed in any of claims 1 to 1 2.

14. A highly soluble, finely agglomerated detergent as claimed in claim 1 3 having a high surfactant content.

1 5. A highly soluble, finely agglomerated detergent as claimed in claim 1 3 having a high content of sprayed-on alkali metal silicate solution.