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(11) | EP 0 974 641 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 158(3) EPC |
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| (54) | HOMOGENOUS GRANULES COMPRISED OF SODIUM TRIPOLYPHOSPHATE, SODIUM SULPHATE AND SODIUM CARBONATE, PROCESS FOR ITS PREPARATION AND APPLICATIONS TO DETERGENTS AND WASHING AGENTS |
| (57) The granules comprised of 40 to 80 % by weight of sodium tripolyphosphate, 20 to
70 % by weight of sodium sulphate, and 5 to 40 % by weight of sodium carbonate. Said
granules have a total fluidity and mobility (free-flowing), an apparent density between
600 and 1,000 g/L, a particle size smaller than 1,500 µm, a chemically bound water
content between 0.2 % and 10 % by weight, an non-bound free water content smaller
than 1 % by weight, and an absorptivity of non-ionic surfactants of at least 20 %.
The granules can be obtained by a hydration/agglomeration process with a liquid ligand.
The granules are appropriate as raw material in the formulation of compact detergent
compositions by atomization or by dry mixing and/or agglomeration. |
FIELD OF THE INVENTION
[0001] The invention relates to homogeneous granules composed of sodium tripolyphosphate, sodium sulphate and sodium carbonate, useful as raw material in the formulation and detergent and washing agent manufacture processes.
BACKGROUND OF THE INVENTION
[0002] Numerous current detergent and washing agent compositions, based on sodium tripolyphosphate (TPF) as the basic component and main builder, also contain other majority ingredients such as sodium carbonate, that act as co-builder, and sodium sulphate, a classic filler component, in their formulation.
[0003] Despite the tendency in recent years in the detergent industry moving towards more "compact" detergent compositions, currently the two main types of process for the preparation of powder and/or granulated detergents are still extensively used. In the first type, based on atomisation, an aqueous suspension (slurry) of ingredients is dried in a drying tower or atomiser, obtaining granules with high porosity. In the second type, based on dry blending and/or agglomeration, some components of the formulation are mixed and agglomerated with a binder, such as a surface-active agent, preferably non-ionic. In both processes, the physical-chemical properties of the detergent product, such as its effectiveness and washing action, rate of dissolving, apparent density, granulometry, stability of the composition when compressed and fluidity when packaged and applied, are fundamental and define the quality of the process.
[0004] With this tendency towards denser formulations, in the atomisation based processes, additional treatments after the atomiser are used (post-addition or post-tower). Solid ingredients of the formulation are added which are denser than the atomised base. This treatment, of vital importance, is limited to use of ingredients of low hydration to avoid problems characteristic of caking of the detergent by absorption of free water from the atomised granulate.
[0005] In the dry-blending and/or agglomeration based processes, the properties of the final product depend directly on the properties of the constituent ingredients. It is necessary to use either so-called "intelligent raw materials", which are generally commercially expensive, or to resort to mixing and multi-stage agglomeration processes with raw materials with high surfactant absorption capacity (absorbency).
[0006] In many of the formulations developed in both types of process, the main ingredients are based on TPF, sodium carbonate and sodium sulphate.
[0007] The Polish patent PL 118.429 describes the formation of a mixture made up of a Glauber salt (Na2SO4.10H2O), TPF and/or sodium carbonate by mixing the ingredients, which are then mixed with a concentration of detergent to give a concentrated detergent powder. However, said Polish patent does not describe the characteristics of the ingredients of the mixture and, furthermore, the aforementioned mixture can only be applied to the manufacture of detergent powders by pulverisation.
[0008] In the present invention a homogeneous granulate is described, with total fluidity and mobility (totally free-flowing), the mixture of said ingredients, that allows it to be used advantageously as a base raw material (builder) in both types of process avoiding the complexity and aforementioned problems for each process. This material is compatible with the current detergent manufacturing installations, and would not require additional equipment for the post-addition or specially designed agglomerates for this process.
[0009] TPF is a chemical product with a variety of uses and applications, and is a key component in the formulation of detergents. When choosing the quality and type from those available commercially to be used in the detergent and therefore in the granulate object of the present invention, it is of critical importance to select the product most suitable for technical and economic success.
[0010] Conventionally, TPF is obtained by calcination of orthophosphate sodium salts. The procedure starts with the reaction of phosphoric acid and an alkaline compound of sodium, such as sodium carbonate and/or sodium hydroxide, to produce in a first instance an aqueous suspension of sodium orthophosphate with a molar proportion Na:P of 5:3, commonly denominated "ortho liquor". This suspension is dried and calcined in a rotary calcinator at a high enough temperature to form anhydrous TPF.
[0011] The resulting TPF from this calcination process is an anhydrous crystalline product that can exist in two crystalline structures, designated as Phase I and Phase II, depending on the calcination temperature. A commercial TPF containing a ratio Phase II/Phase I of 20/70 is obtained in a rotary calcinator at a calcination temperature lying between 500 and 560°C.
[0012] A characteristic property of TPF in its hydration reaction in the presence of water to form the hexahydrated species (TPF.6H2O). The speed of this reaction and therefore of the stability of the resulting hexahydrated crystal depends directly on the characteristics of the TPF used with regards to the Phase I/Phase II contents, granulometry and water content, i.e. whether it is anhydrous or pre-moistened.
[0013] Clogging of TPF is well known in the detergent industry as is its tendency to form agglomerates (caking) in the aforementioned hydration reaction when coming into contact with water. This behaviour leads to problems related to its processing during the manufacture of the detergent, as well as during it use by the consumer. In this case, the compression can occur on the inside of the detergent packaging or in the dispenser of the washing machine when it comes into contact with the water of the wash.
[0014] The TPF used in the manufacture of the homogeneous granules object of this invention avoids the aforementioned problems and is characterised by having a Phase I content, a pre-moistened water content and a pre-determined granulometry suitable for the required ends.
SUMMARY OF THE INVENTION
[0015] An object of this invention constitutes some homogeneous granules, of total fluidity and mobility (totally free-flowing), that comprise TPF, sodium sulphate and sodium carbonate. This granules have some properties, such as apparent density, non-ionic surfactant absorption capacity (absorbency), granulometry, content of chemically bound water such as crystallisation water or hydration water and non-bound free water, which make them suitable for use as a raw material in the formulation of detergents produced by atomisation or by dry blending and/or agglomeration.
[0016] An additional object of this invention constitutes a procedure for manufacturing the homogeneous granules object of this invention, that comprises using a liquid binder for hydrating/agglomerating the components, drying the resulting granules and separating the desired product fraction.
[0017] An another additional object of this invention constitutes the use of the homogeneous granules object of this invention in the processes and formulations of detergent compositions. These and other objects, characteristics and advantages of the invention are detailed in the following description.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The invention provides homogeneous granules, of total fluidity and mobility (totally free-flowing), hereinafter the granules of the invention, that comprise:
- 40-80 % by weight sodium tripolyphosphate (TPF),
- 20-70 % by weight sodium sulphate, and
- 5-40 % by weight sodium carbonate.
[0019] The granules of the invention have an apparent density lying between 600 and 1,000 grams/litre (g/L), preferably between 700 and 900 g/L, a particle size distribution of less than 1,500 micrometers (µm), preferably with an average diameter lying between 150 and 800 µm, a chemically bound water content of between 0.2 and 10 % by weight, a non-bound free water content less than 1 % by weight, and a capacity for absorption of non-ionic surfactants (absorbency) of, at least, 20 %, preferably between 23 and 25 %.
[0020] By the term "fluidity" or "free-flowing" objective of the granules of the invention, it is understood the total and sufficient mobility of the product, capable of being poured or dosed as a reproducible average quantity.
[0021] The "absorption capacity" or "absorbency" defines the capacity of the particle for absorbing the liquid components of the formulation of a detergent composition. Values of high absorbency are necessary in free-flowing formulations of detergents that contain non-ionic surface-active agents characteristic of the dry blending and/or agglomeration processes of production. Values of above 10 % are generally desired, values greater than 15 % are considered very good, and values greater than 20 % are excellent or highly absorbent.
[0022] TPF hydrolysis is characteristic of certain formulations based on TPF as a structural component (builder), especially in atomised detergent compositions and in those with production by means of agglomeration with ionic surface-active agents, resulting in a loss of effectiveness and detergent efficiency of the said compositions due to the presence of the species ortho- and pyrophosphates arising from reversion of TPF.
[0023] The granules of the invention have a TPF content lying between 40 and 80 % by dry weight of the granules. A characteristic of the invention is to specify their existence in granules as "true" TPF, that is to say, excluding other phosphate forms from, to give a TPF richness of at least 94 %. This point is particularly important as it means that in the application of the granules of the invention, TPF is also present at at least the same richness of 94 % in the detergent formulation.
[0024] The characteristics of the ingredients of the granules of the invention will be treated in detail when a procedure for the production thereof is described.
[0025] The manufacturing procedure for the granules of the invention comprises the stages of:
a) adding a liquid binder to a mixture that comprises TPF, sodium sulphate and sodium carbonate, in appropriate quantities, to form some moistened granules;
b) drying the resulting moistened granules from stage a) in order to completely or partially eliminate the liquid binder that is chemically unbound; and
c) separating the desired granulometric fraction from the dry granules arising from
stage b).
Raw Materials
[0026] The raw materials that constitute the composition of granules of the invention are TPF, sodium sulphate and sodium carbonate. The TPF used in the production of the granules of the invention are characterised by being mostly of type Phase I, with a Phase I content lying between 20 and 70% by weight with respect to the total amount of TPF, a Phase I content preferably lying between 40 and 55 %, a pre-moistened water content lying between 0.3 % and 1.5 % by weight, preferably between 0.5 and 1 %, and a granulometry with an average particle size less than 250 µm, preferably with a content of fine particles, that is to say, less than 150 µm, of at least 75 %.
[0027] These characteristics of TPF used for producing the granules of the invention are considered critical in the first stage of the procedure (stage of hydration/agglomeration) for controlling the degree of agglomeration and the physical properties of the resulting granules with regards their apparent density and porosity/absorbency.
[0028] The sodium carbonate used in producing the granules of the invention are characterised by having a minimum richness of sodium carbonate (Na2CO3) of 99 % by weight, a particle size preferably lying between 9 and 100 mesh (Standard Tyler Mesh), and an apparent density of, at least, 500 g/L, and preferably greater than 800 g/L.
[0029] The sodium sulphate used in the production of the granules of the invention is characterised by having a minimum richness of sodium sulphate (Na2SO4) of 99 % by weight, a particle size preferably lying between 16 and 270 mesh (Stand Tyler Mesh), and an apparent density of, at least, 1,000 g/L, and preferably greater than 1,400 g/L.
[0030] These three ingredients are dosed in the proportions corresponding to the composition of the granules of the invention and are mixed and homogenised prior to the first stage (hydration/agglomeration).
First stage: Hydration/Agglomeration
[0031] The appropriate mixture of TPF, sodium sulphate and sodium carbonate is fed to the hydration stage to give homogeneous moistened granules, by means of the agglomeration of the ingredients of the mixture by hydration with a liquid binder. The liquid binder used in the procedure of the invention is water. The term "water", as it is used here, refers to pure water or water containing small quantities, that is to say, less than 15 % by weight, of TPF, sodium sulphate and sodium carbonate in proportions identical to those of the granules of the invention.
[0032] The carry out this stage, enough liquid binder is added to hydrate the feed material and obtain moistened granules that contain, at least, 5 % water, preferably between 5 and 10 % water, the amount of water consisting of the sum of free water and water chemically bound for hydration or crystallisation.
[0033] The temperature of the water is not critical although it preferably lies in the range 10 to 40°C. In general it is not necessary or practical to employ temperatures above 50°C or less than 5°C. Due to the heat generated by the hydration of TPF, sodium sulphate and sodium carbonate when forming the stable hydrated species, it is critical, according to the invention, that the raw feed materials for this hydration stage are at a temperature less than 60°C, preferably less than 40°C.
[0034] The hydration process of the feed material is submitted to stirring while the liquid binder is added, which leads to a more uniform distribution and spread of the water in the feed, as well as the tendency for agglomeration to occur, especially with the most fine particles less than 150 µm. Stirring is preferably effected by rotation in a horizontal rotary hydrator with inner lifting and turning paddles.
[0035] Pulverisation is the preferred method of the invention for adding the liquid binder and this can be carried out using conventional pulverisation systems with atomisation air nozzles or pneumatic pulverisers.
[0036] The residence time in the hydrator is a critical parameter of the invention for obtaining the agglomeration of the feed material as well as for guaranteeing the chemical absorption of the water added and the TPF hydration, sodium sulphate and sodium carbonate. In the procedure of the invention the residence time is from, at least, 5 minute, and preferably between 5 and 10 minutes.
[0037] As a result of the hydration stage, moistened granules are obtained where most of the water present is chemically bound to said granules as hydration or crystallisation water, and only a small portion of the water is to be found as unbound free water which is eliminated in the drying stage.
Second stage: Drying
[0038] The drying stage can be carried out by passing the previously obtained moistened granules through a jet of hot air, in a rotary horizontal drier with inner lifting and turning paddles. The temperature of the hot gases lies approximately between 80 and 250°C. Preferably, the moistened granules are dried until reaching a free humidity weight of 1 % in the granules of the invention, and so the residence time in the drier is also critical, being at least 5 minutes, preferably between 5 and 20 minutes, depending on the desired degree of hydration in the dry granules. With the procedure of the invention granules are obtained with a total water content of between 0.2 and 10 % by weight as crystallisation water, and less than 1 % by weight of free humidity.
Third stage: Sieving
[0039] The dry granules from the previous stage are sieved to separate the desired granulometric fraction into the final product. For commercial purposes, the particle distribution obtained in the present invention is less than 1,500 µm, preferably with an average size lying between 150 and 800 µm.
[0040] The manufacturing procedure for the granules of the invention can be carried out in batches or, preferably, continuously. In a particular realisation of the invention procedure, the fraction of the large particles rejected by the sieve in the third stage are ground, preferably to give a size less than 1,500 µm, and recycled to be fed into the first stage (hydration/agglomeration).
[0041] The granules of the invention are useful as raw material in the formulation and manufacturing processes of detergents and washing agents, in particular, in the treatment of mixtures and densifying powder detergents or atomised granules and in processes for manufacturing detergents by dry blending and/or agglomeration. Therefore, the invention provides a procedure for manufacturing powder detergents and washing agents and/or granules by dry blending and/or agglomeration that comprises the use of the homogeneous granules of the invention as raw material, as well as a procedure for manufacturing densified atomised detergents that comprises the use of the granules of the invention as a post-atomiser treatment (post-addition or post-tower).
[0042] To make this invention easier to understand, an example is included for illustrative purposes, that is not to be taken as limiting the scope of this invention.
[0043] For the analytical determination of the capacity of absorption (absorbency) of the granules of the invention the analytical method followed is that corresponding to ISO 150, based on the absorption of an oil. According to this method, the sample is mixed with an acid until saturation is reached at the end of the mixing, and the percentage weight of oil required is the value of the capacity of absorption or absorbency. No special prior treatment for the sample is required.
[0044] The oil used is linseed oil and should comply with the ISO 150, with a specific weight of 0.93 grams/millilitre (g/mL). The equipment necessary is a watch glass (about 15 cm in diameter), a graduated micro-burette with a capacity going from 5 or 10 mL with divisions of 0.05 mL, accurate scales (± 0.01 g), and a flexible spatula of stainless steel (approximately 10 cm long and 2 cm wide).
[0045] 5.0 g of sample are weighed to an accuracy of ± 0.01 g and placed on the watch glass. The micro-burette is filled with oil and the zero level readjusted once the oil has ran slowly over the walls. Initially, 10 drops of oil are added, which disperse throughout the sample, and are completely mixed with the spatula. Oil is added until a dry and crumbly mixture is obtained. Once this point is reached, the oil is added dropwise, mixing after each drop is added, until a soft paste which appears sticky throughout is obtained that sticks to the spatula blade, both when lifting up the sample and when turning it over. The volume of oil used is recorded (± 0.01 mL).
[0047] The results of several repetitions of the same sample should produce a standard deviation less than 1 % of the average value.
EXAMPLE
Manufacture of homogeneous granules
[0048] This example illustrates a continuous procedure for manufacturing the granules of the invention and relates to the operating conditions, to the composition and to the properties of the final granules.
[0049] The resulting granules of this Example have been obtained by feeding (1,818 kg/h) homogenised mixture of TPF, sodium sulphate and sodium carbonate (1,000 kg/h of TPF, 546 kg/h of sodium sulphate and 272 kg/h of sodium carbonate) into a horizontal rotary hydrator (approximately 4.6 m long and with a diameter of approximately 0.7 cm) equipped with 5 pulzerisation nozzles. The rotation speed was 20 rpm and the mixture was pulverised with water at 20-25°C, until a total content of 9 % by weight of the feed mixture was reached, with a residence time of 10 minutes.
[0050] The granulated product leaving the hydrator was fed continuously into a horizontal rotary drier (approximately 5 m long and with a diameter of approximately 1 m) with a speed of rotation of 12 rpm. The drying was carried out in different operating conditions with input of hot gases between 80 and 250°C and residence times of between 5 and 15 minutes, to attain final water contents lying between 0.2 and 8 % by weight, and less than 1 % in free humidity. The drying conditions were as follows:
| Case | Temperature of hot gases (°C) | Residence time in drier (minutes) |
| 1 | 225 | 12 |
| 2 | 180 | 10 |
| 3 | 150 | 5 |
[0051] In all cases (cases 1, 2 and 3), the dry granulate was classified using a sieve with a cut-off using a mesh cloth of 1.12 mm with square holes.
[0052] Homogeneous granules were obtained with composition of dry base of 55 % by weight TPF, 30 % by weight of sodium sulphate and 15 % by weight of sodium carbonate, with a granulometry less than 1,000 µm, a final capacity for absorption of non-ionic surface-active agents of 20 to 25 %, and total water contents lying between 0.2 and 8 % by weight, and less than 1% by weight of free humidity.
| CONTINUOUS PRODUCTION OF HOMOGENEOUS GRANULES COMPOSED OF TPF, SODIUM SULPHATE AND SODIUM CARBONATE, BY MEANS OF HYDRATION, DRYING AND SIEVING | |||||||
| FEED | + 9 | + 16 | - 35 | +100 | -100 | Mesh (Mever) | |
| TPF | 55 % | - | - | 1.0 % | 15 % | 83.5 % | |
| Na2SO4 | 30 % | - | - | 2.0 % | 85 % | 13.5 % | |
| Na2CO3 | 15 % | - | 5 % | 67 % | 25 % | 3 % | |
| Final granulate (comp. dry base) | % | % total humidity | % free humidity | Apparent density (g/L) | Absorbitivty | |
| TPF | 55 | |||||
| Na2SO4 | 30 | |||||
| Na2CO3 | 15 | |||||
| Case 1 | 0.2 | 0.2 | 725 | 25 % | ||
| Case 2 | 4.5 | 0.2 | 800 | 23 % | ||
| Case 3 | 8.0 | 0.2 | 825 | 20 % | ||
| GRANULOMETRY | + 9 | + 16 | + 35 | + 100 | - 100 | Tyler Mesh |
| Final granulate | - | - | 15 % | 85 % | - |
- 40-80 % by weight sodium tripolyphosphate (TPF),
- 20-70 % by weight sodium sulphate, and
- 5-40 % by weight sodium carbonate,
and that has an apparent density lying between 600 and 1000 grams/L, a particle size less than 1,500 µm, a content of chemically bound water of crystallisation or hydration between 0.2 % and 10 % by weight, a unbound free water content of at least 1 % by weight, and an non-ionic surfactant absorption capacity (absorbency) of at least 20 %.a) adding a liquid binder to a mixture that comprises TPF, sodium sulphate and sodium carbonate, in appropriate quantities, to form moistened granules;
b) drying the resulting moistened granules from stage a) to completely or partially eliminate the chemically unbound binder; and
c) separating the desired granulometric fraction from the dry granules arising from stage b).
Amended claims under Art. 19.1 PCT
1. A homogeneous granulate, of total fluidity and mobility (totally free-flowing), that comprises:
- 40-80 % by weight sodium tripolyphosphate (TPF),
- 20-70 % by weight sodium sulphate, and
- 5-40 % by weight sodium carbonate,
and that has an apparent density lying between 600 and 1000 grams/L, a particle size less than 1,500 µm, a content of chemically bound water of crystallisation or hydration between 0.2 % and 10 % by weight, a unbound free water content of at least 1 % by weight, and an non-ionic surfactant absorption capacity (absorbency) of at least 20 %.2. A granulate according to claim 1, in which the apparent density lies between 700 and 900 g/L.
3. A granulate according to claim 1, in which the average diameter lies between 150 and 800 µm.
4. A granulate according to claim 1, in which said capacity of absorption of non-ionic surfactants (absorbency) lies between 23 and 25 %.
5. A procedure for producing a homogeneous granulate, of total fluidity and mobility (totally free-flowing), according to claim 1, that comprises:
a) adding a liquid binder to a mixture that comprises TPF, sodium sulphate and sodium carbonate, in appropriate quantities, to form moistened granules;
b) drying the resulting moistened granules from stage a) to completely or partially eliminate the chemically unbound binder; and
c) separating the desired granulometric fraction from the dry granules arising from stage b).
6. A procedure according to claim 5, in which said TPF used as raw material has a purity of, at least, 94 %.
7. A procedure according to claim 5, in which said TPF used as raw material has a TPF of type Phase I content lying between 20 and 70 % of the total TPF, preferably between 40 and 55 %.
8. A procedure according to claim 5, in which said TPF used as raw material has a water content of pre-moistening lying between 0.3 % and 1.5 % by weight, preferably between 0.5 % and 1 % by weight.
9. A procedure according to claim 5, in which said TPF used as raw material has a granulometry with an average particle size less than 250 µm.
10. A procedure according to claim 9, in which at least 75 % of said TPF used as raw material has a granulometry with an average particle size less than 150 µm.
11. A procedure according to claim 5, in which said sodium carbonate used as raw material has a minimum richness of 99% by weight of sodium carbonate.
12. A procedure according to claim 5, in which said sodium carbonate used as raw material has a particle size lying between 9 and 100 mesh (Tyler mesh).
13. A procedure according to claim 5, in which said sodium carbonate used as raw material has an apparent density of at least 500 g/L, preferably greater than 800 g/L.
14. A procedure according to claim 5, in which said sodium sulphate used as raw material has a minimum richness of 99 % by weight of sodium sulphate.
15. A procedure according to claim 5, in which said sodium sulphate used as raw material has a particle size lying between 16 and 270 mesh (Tyler mesh).
16. A procedure according to claim 5, in which said sodium sulphate used as raw material has an apparent density of at least 1,000 g/L, preferably greater than 1,400 g/L.
17. A procedure according to claim 5, in which said liquid binder is selected from a group made up of water and water that contains a quantity less than 15 % by weight of the mixture in accordance with the composition indicated in claim 1.
18. A procedure according to claim 5, in which the addition of liquid binder during stage a) is carried out by pulverisation.
19. A procedure according to claim 18, in which said pulverisation is carried out using atomisation air nozzles or pneumatic pulverisers.
20. A procedure according to claim 5, in which the liquid binder is added at a temperature lying between 10 and 40° C.
21. A procedure according to claim 5, in which the temperature of the TPF feed, sodium sulphate and sodium carbonate is less than 60° C, preferably less than 40° C.
22. A procedure according to claim 5, in which stage a) is carried out with stirring.
23. A procedure according to claim 22, in which said stirring is carried out by rotation in a horizontal rotary hydrator with inner lifting and turning paddles.
24. A procedure according to claim 23, in which the residence time of the material fed into said rotary hydrator is, at least, 5 minutes, preferably between 5 and 20 minutes.
25. A procedure according to claim 5, in which the resulting moistened granules from stage a) have a water content of, at least, 5 % by weight, preferably between 5 and 10 % by weight.
26. A procedure according to claim 25, in which the water present in the moistened granules resulting from stage a) are mostly found as water bound chemically as hydration or crystallisation water.
27. A procedure according to claim 5, in which the drying stage b) is carried out by passing the moistened granules resulting from stage a) through a jet of hot air, with a temperature lying between 80 and 250° C, until dry granules are obtained with a free humidity of less than 15 by weight.
28. A procedure according to claim 27, in which the drying of the moistened granules resulting from stage a) is carried out in a horizontal rotary drier with inner lifting and turning paddles.
29. A procedure according to claim 28, in which the residence time of the moistened granules resulting from stage a) is at least 5 minutes, preferably between 5 and 20 minutes.
30. A procedure according to claim 5, in which the separation and classification of the desired granulometric fraction in stage c) is carried out by sieving the dry granules resulting from stage b).
31. A procedure according to claim 30, in which the granules obtained after stage c) have a particle distribution less than 1,500 µm.
32. A procedure according to claim 31, in which the granules obtained after stage c) have an average diameter lying between 150 and 800 µm.
33. A procedure according to claim 5, which is carried out in continuous fashion.
34. A procedure according to claim 5, which further comprises the stage of separating the fraction of large particles rejected in stage c), grinding said particles down to a size less than 1,500 µm, and recycling the ground particles to feed them into stage a).
35. A procedure for manufacturing powder detergents and washing agents and/or granules by dry blending and/or agglomeration that comprises use of the homogeneous granules according to claim 1 as raw material.
36. A procedure for producing densified atomised detergents that comprises the use of homogeneous granules according to claim 1 as a post-atomiser treatment (post-addition or post-tower).