MXPA99011599A - Production of detergent granulates - Google Patents

Abstract

A granular detergent product is made by spraying a liquid binder to contact a particulate solid starting material in a low shear granulator such as a fluidised bed apparatus. The d3,2 average droplet diameter is not greater than ten times the d3,2 average particle diameter of that fraction of the solid starting material which has a d3,2 particle diameter of from 20&mgr;m to 200&mgr;m provided that if more than 90%by weight of the solid starting material has a d3,2 average particle diameter less than 20&mgr;m, then the d3,2 average particle diameter of the total solid starting materials shall be taken to be 20&mgr;m. If more than 90%by weight of the solid starting material has a d3,2 average particle diameter greater than 200&mgr;m, then the d3,2 average particle diameter of the total starting solid material shall be taken to be 200&mgr;m.

Description

PROCEDURE FOR THE PRODUCTION OF GRANULATED DETERGENTS Description of the invention The present invention relates to a process for the production of granular detergent compositions. It has been well known in the art to obtain detergent powders by spray separation. However, the spray drying process requires a large amount and energy and consequently the resulting product is expensive. More recently, there has been much more interest in the production of granular detergent products by processes that mainly employ mixing, without the use of spray drying. These spray mixing techniques can offer great flexibility in the production of powders of various different compositions from a single plant by various post-dosing components after an initial granulation step. A known type of mixing process, which does not involve spray drying, employs a moderate speed granulator (a common example often referred to colloquially as a "plow grate", optionally preceded by a high speed mixer (an example). common commonly referred to colloquially as a 'recycler' due to its cooling system by recycling.) Typical examples of such processes are described in European patent specifications EP-A-367 339, EP-A-390 251 and EP- A-420 317. These moderate speed and high speed mixers exert relatively high levels of cut on the materials that are processed, and only recently, there has been less effort in the development of the use of mixers or low cut granulators. of low-cut equipment is a gas fluidization granulator.In this type of apparatus, a gas (usually air) is blown through a body of particulate solids. on which a liquid component is sprayed. A gas fluidization granulator is sometimes called a "fluidized bed" granulator or mixer. However, this is not strictly accurate since such mixers can be operated with such a high gas flow velocity that a classic "bubbling" fluid bed is not formed.

Although low-cut granulators can give good control of bulk density, there is still a need for greater flexibility and in particular, for the production of lower bulk density powders. The processes that involve low-cut granulation are very varied. Indian Patent No. 166307 (Unilever) discloses the use of a gas, recirculation, internal fluidization granulator and explains that the use of a conventional fluidized bed will lead to a sticky, lumpy product. The East German Patent No. 140 987 (VEB Waschmittelwerk) describes a continuous process for the production of granular washing and cleaning compositions, wherein the liquid non-ionic surfactants or the acid precursors of the anionic surfactants are sprayed onto a powdery, fluidized additive material, especially sodium tripolyphosphate ( STPP) having a high phase II content to obtain a product with bulk density in the range of 530-580 g / 1. The international application WO96 / 04359 (Unilever) describes a process by which powders of low bulk density are prepared by contacting a neutralizing agent such as an alkaline detergent additive and a liquid acid precursor, of an anionic surfactant in a fluidization zone to form the detergent granules. It has now been found that in systems where a liquid binder is sprayed onto a powder and / or granular solid in a low cut granulator, the size of the droplet in the spray with respect to the particle size of the solids determines the granule, the bulk density and the yield of the process. Thus, the present invention provides a process for the production of a granular detergent product, the process comprising sprinkling droplets of a liquid binder to contact a solid initial material, particulate in a low cut granulator, wherein the average droplet diameter d3.2 of the liquid binder is not more than 10 times, preferably not more than 5 times, more preferably not more than 2 times and more preferably not greater than average particle diameter d3.2 of that fraction of the total solid, total material which has a particle diameter d3.2 of 20 μm to 200 μm, with the proviso that if more than 90% by weight of the solid initial material has an average particle diameter d3.2 less than 20 μm, then the average particle diameter d3.2 of the total solid, total material will be taken as 20 μm, and if more than 90% by weight of the solid initial material has a diameter of average particle d3.2 greater than 200 μm then the average particle diameter d3.2 of the total solid initial material will be taken as 200 μm. In the context of the present invention, the term "granular detergent product" encompasses granular finished products for sale, as well as granular components or adjuvants for the formation of finished products, for example, by post-dosing to or with, or any other form of mixing, with additional components or adjuvants. Thus a granular detergent product as defined herein may or may not contain detergent material such as synthetic surfactant and / or soap. The minimum requirement is that it should contain at least one material of a general type of conventional component of granular detergent products, such as a surfactant (including soap, an additive, a bleach or a whitening system component, an enzyme, a stabilizer enzyme or a component of an enzyme stabilization system, a soil anti-redeposition agent, a fluorescer or an optical brightener, an anti-corrosion agent, an anti-foam agent, a perfume or a colorant. The term "powder" refers to materials consisting substantially of grains of individual materials and mixtures of such grains.The term "grain" refers to a small particle of the agglomerated powder materials.The end product of the process according to this invention consists of, or comprises a high percentage of granules, however, additional granular and / or powder materials may be pos optionally dosed to such a product. The solid starting materials of the present invention are particulate and may be in the form of powder and / or granules. All references herein to the average d3.2 of the initial solid materials refer to the average diameter d3, only of the solids immediately before they are added to the low-cut granulation process, per se. For example, hereinafter described how a low cut granulator can be fed by at least partially pregranulated solids from a premixer. It is very important to note that the "solid initial material" has to be built to understand all the material coming from the pre-mixer, which is fed to the low-cut granulation process but does not include all the solids as they are dosed to the premixer and / or direct to any other stage of processing until processing, or after completion of processing in the low-cut granulator. For example, a layered or auxiliary flow agent added after the granulation process in the low cut granulator does not constitute a solid starting material. The process of the present invention can be carried out either in batches or in a continuous mode of operation, as desired. Whether the low-cut granulation process of the present invention is a batch process or a continuous process, the solid initial material can be introduced at any time during the time when the liquid binder is being sprayed. In the simplest form of the process, the solid initial material can be first introduced to the low cut granulator and then sprayed with the liquid binder. However, some of the solid initial material could be introduced at the beginning of processing in the low cut granulator and the rest introduced in one or more subsequent times, either as one or more discrete batches or continuously. However, all such solids fall within the definition of "solid initial material". The diameter d3.2 of the initial solid materials is that obtained by, for example, a conventional laser diffraction technique (e.g., using a Helos Sympatec instrument) or sieved as it might be well known to a person skilled in the art. Suitably, the solid starting material (s) have a particle size distribution such that no more than 5% by weight of the particles have a particle size greater than 250 μm. It is also preferred that at least 30% by weight of the particles have a particle size below 100 μm, more preferably below 75 μm. However, the present invention is also usable with larger fractions of solid starting materials (e.g. >); 5% greater than 250 μm, optionally also < 30% below 100 μm or 75 μm) but this increases the opportunity for some crystals of non-agglomerated initial materials to be found in the final product. This presents a cost benefit by allowing the use of cheaper raw materials. In any case, the solid or particulate starting materials have an average particle size below 500 μm to provide detergent powders having a low apparent density, particularly desired. Within the context of the solid initial materials, reference is made to an average particle size and means the average particle diameter d3.2- The average droplet diameter d3, maximum is preferably 200 μm, for example 150 μm, more preferably 120 μm, still more preferably 100 μm, and more preferably still 80 μm. On the other hand, the minimum droplet diameter d3 is 20 μm, more preferably 30 μm and more preferably 40 μm. It should be noted that in the specification of any particular preferred range herein, no particular average droplet diameter d3.2 is associated with any average, minimum droplet diameter d3.2. Thus, for example, a preferred range could be constituted by 150-20 μm, 150-30 μm, 150-40 μm, 120-20 μm, 120-30 μm and so on. The average droplet diameter d3.2 is suitably measured, for example, using a laser phase Doppler anemometer, or a laser light scattering instrument (e.g., as supplied by Malvern or Sympatec- as it might be well known by a The present invention is not specific to the use of any particular type of low cut granulator, but if a type of gas fluidization is selected, then the liquid binder can be sprayed from above and / or from below and / or from within the fluidized solids fog The invention also encompasses a granular detergent composition obtainable by a process according to the present invention The present invention not only provides control of particle size and bulk density in the final product, It also prevents the production of irregularly shaped particles, which also makes it possible for the process to be controlled in a way that ensure that fluidization continues unimpeded, especially (though not exclusively) when the low cut granulator is of the gas fluidization type. Preferably, but not exclusively, in the process according to the present invention, the low-cut granulator is of the gas fluidization type and comprises a fluidization zone in which the liquid binder is sprayed onto the solid material. However, a mixer / granulator could also be used by rotating drum or by kettle. The low-cut granulator (of any type) can be adapted by recycling "fine materials" such as powdered or partially granular material of very small particle size, so that these are returned to the entrance or any other stage of the operation of the low cut granulator and / or any pre-mixer. The fine materials recycled in this manner, especially but not exclusively for a low cut granulator operating in the continuous mode, can be recycled as an auxiliary to the flow and / or as a stratifying agent as described hereinafter. A further aspect of the invention can provide a process for the formation of a granular detergent product, the process comprising, in a low cut granulator, contacting a solid fluidized starting material with a liquid binder spray, extracting fine particulates. during the granulation and reintroducing the fine particulates to the process, to act as an auxiliary flow or stratification agent. Preferably, the fine particulates are elutriated materials, for example, these are present in the air leaving a gas fluidization chamber. Further, when the low cut granulator is of the gas fluidization type it can sometimes be preferably to use equipment of the type provided with a vibrating bed. In a preferred class of processes according to the present invention, the liquid binder comprises an acid precursor of an anionic surfactant, and the solid starting material comprises an inorganic alkaline material. Such an acid precursor may for example be the acid precursor of a linear alkylbenzene sulfonate (LAS) or an anionic primary alkyl sulfate (PAS) surfactant or any other type of anionic surfactant.

Suitable materials for use as the inorganic alkaline material include alkali metal carbonates and bicarbonates, for example sodium salts thereof. The neutralizing agent is most preferably present at a level sufficient to completely neutralize the component, acid. If desired, a stoichiometric excess of the neutralizing agent may be employed to ensure complete neutralization or to provide an alternative function, for example as a detergency builder, for example if the neutralizing agent comprises sodium carbonate. The liquid binder may alternatively or additionally contain one or more other liquid materials such as liquid nonionic surfactants and / or organic solvents. The total amount of acid precursor will normally be as high as possible, subject to the presence of any other components in the liquid, and subject to other considerations referred to below. Thus, the acid precursor can constitute at least 98% (for example, at least 95%) by weight of the liquid binder, but could be at least 75%, at least 50% or at least 25% by weight of the binder . This may even constitute, for example, 5% or less by weight of the binder. Of course, the acid precursor can be completely omitted, if required. When the liquid non-ionic surfactant is present in the binder together with an acid precursor of an anionic surfactant, then the weight ratio of all the acid precursors to the nonionic surfactants will normally be from 20: 1 to 1:20. However, this ratio can be, for example, 15: 1 or less (of the anionic), 10: 1 or less, or 5: 1 or less. On the other hand, the non-ionic component may be the major component, so that the ratio is 1: 5 or more (of the non-ionic material) 1:10 or more, 1:15 or more. The proportions in the range of 5: 1 to 1: 5 are also possible. For the manufacture of granules containing anionic surfactant, it will sometimes be desirable not to incorporate all such anionic by neutralization of an acid precursor. Some may optionally be incorporated in the form of alkali metal salt, dissolved in the liquid binder or even as part of the solids. In that case, the maximum amount of the anionic incorporated in the salt form (expressed as the percentage by weight of the total anionic surfactant salt in the output of the product from the low cut granulator) is preferably not greater than 70%, more preferably not greater than 50% and still more preferably no greater than 40%. If it is desired to incorporate a soap into the granules, this can be carried out by incorporating a fatty acid, either in solution in the liquid binder or as part of the solids. The solids in any case must then also comprise an alkaline, inorganic neutralizing agent, to react with the fatty acid to produce the soap. The liquid binder will often be totally or substantially non-aqueous, that is, any water present does not exceed 25% by weight of the liquid binder, but preferably not more than 10% by weight. However, if desired, a controlled amount of water may be added to facilitate neutralization. Typically, the water can be added in amounts of 0.5 to 2% by weight of the final detergent product. Any such water is suitably added before or together, or alternately with the addition of the acid precursor.

Alternatively, an aqueous liquid binder may be employed. This is especially suitable for manufacturing products that are adjuvants for subsequent mixing with other components, to form a fully formulated detergent product. Such adjuncts or auxiliaries, apart from the resulting components of the liquid binder, usually will consist mainly of one, or a small number of components normally found in the detergent compositions., for example, a surfactant or an additive such as zeolite or sodium tripolyphosphate. However, this does not exclude the use of aqueous liquid binders for granulation if they are substantially completely formulated products. In any case, typical aqueous liquid binders include aqueous solutions of alkali metal silicate, water-soluble acrylic / maleic polymers (for example Sokalan CP5) and the like. In a refinement of the process of the present invention, the solid initial material can be contacted and mixed with a first portion of the liquid binder, for example in a low, moderate or high shear mixer (e.g. a premixer) to form a partially granulated material. The latter can then be sprayed with a second portion of the liquid binder in the low cut granulator to form the granulated detergent product. Such a two-stage granulation process is preferred, but it is not absolutely necessary, for the total liquid binder, that it be dosed only in the partial granulation pre-mixer and in the low-cut granulation steps. Similarly, some of the material could be dosed before the partial granulation premix and / or other previous processing steps. Also, the content of the liquid binder could be varied between the first and second stages. The degree of granulation in the pre-mixer (for example partial granulation) and the amount of granulation in the low-cut granulator is preferably determined according to the desired density of the final product. In this way, the preferred quantities of the liquid binder to be dosed in each of the two steps can be varied: (i) If a lower powder density is desired, for example 350-650 g / 1 (a) 5-75% by weight of the total liquid binder is preferably added in the premixer / and (b) the remaining 95-25% by weight of the total liquid binder is preferably added in the low cut granulator. (ii) if higher density of the powder is desired, for example 550-1300 g / 1 (a) 75-95% by weight of the total liquid binder is preferably added in the premixer; and (b) the remaining 25-5% by weight of the total liquid binder is preferably added in the low cut granulator.

If an initial pre-mixer is used for partial granulation, an appropriate mixer for this step is a high-cut Lodige® CB machine or a moderate-speed mixer such as a Lodige® KM machine. Other suitable equipment includes the DraisR T160 series manufactured by Drais Werke GmbH, Germany; the Littleford mixer with internal shredder blades and turbine type mill mixer that has several blades on an axis of rotation. A low or high cut mixer has a stirring action and / or a cutting action, which are operated independently of one another. Preferred types of low cut or high cut mix granulators are mixers of the FukaeR FS-G series; from the DiosnaR V series of former Dierk & Sohne, Germany; Pharma MatrixR ex T.K. Fielder Ltd, England. Other mixers that are believed to be suitable for use in the process of the invention are FujiR VG-C from Fuji Sangyo Company, Japan; the RotoR of Zanchetta & Company Srl, Italy and the SchugiR Flexomix granulator. Another mixer suitable for use in a pre-granulation stage is the batch mixer of the Lodige (Trade Mark) FM (registered trademark) series (plow gate mixers) from Morton Machine Company, Ltd, Scotland. If a gas fluidization granulator is used as the low cut granulator, then it is preferably operated at a surface air velocity of approximately 0.1-1.2 ms "1, either under positive or negative relative pressure and with an inlet temperature. of air in the range of -10 ° or 5 ° C to 80 ° C, or in some cases, up to 200 ° C. Typical operational temperature within the bed, from about room temperature to 60 ° C. Preferably, the surface air velocity is at least 0.45, and more preferably at least 0.5 ms_1 Preferably, the surface air velocity is in the range of 0.8-1.2 ms-1 Optionally, a "stratification agent" can be introduced at any appropriate stage. "or" an auxiliary flow. "This is to improve the granularity of the product, for example by preventing the aggregation and / or the formation of granule cakes. suitably present in an amount of 0.1 to 15% by weight of the granular product and more preferably in an amount of 0.5 to 5%. Suitable stratification / flow assistants (whether or not introduced by recirculation) include crystalline or amorphous alkali metal silicates, aluminosilicates including zeolites, Dicamol, calcite, diatomaceous earth, silica, for example precipitated silica, chlorides such as chloride of sodium, sulfates such as magnesium sulfate, carbonates such as calcium carbonate and phosphates such as sodium tripolyphosphate. Mixtures of these materials can be used, as desired. In general, additional components can be included in the liquid binder or mixed with the solid neutralizing agent at an appropriate stage of the process. However, the solid components can be post-dosed to the granular detergent product. In addition to any anionic surfactant that can be optionally produced by a neutralization step, additional anionic surfactants, or nonionic surfactant as mentioned above, can also be added at a suitable time, also, cationic, amphoteric or semi-polar surfactants and mixtures thereof. same. In general, suitable surfactants include those generally described in "Surface Active Agents and Detergents" Vol I by Schwartz and Perry. As mentioned above if desired, the soap derivative from saturated or unsaturated fatty acids having, for example, an average of 10 to 18 carbon atoms, may also be present.

If present, the active detergent material is suitably incorporated at a level of 5 to 40%, preferably 10 to 30% by weight of the final granulated detergent product. A complete detergent composition often contains a detergency additive. Such an additive can be introduced with the solid and / or subsequently added material, as desired. The additive may also constitute a neutralizing agent, for example sodium carbonate, in which case sufficient material will be employed for both functions. Generally speaking, the total amount of detergent additive in the granular product is suitably from 5 to 95%, for example from 10 to 80%, more preferably from 15 to 65%, especially from 15 to 50% by weight. The inorganic additives that may be present include sodium carbonate, if desired in combination with a crystallization seed for calcium carbonate, as described in CB-A-1 437 950. Any sodium carbonate will need to be in excess of any used to neutralize the anionic acid precursor if the latter is added during the process.

Other suitable additives include crystalline and amorphous aluminosilicates, for example zeolites as described in British Patent GB-A-1 473 201; amorphous aluminosilicates as described in British Patent GB 1 473 202; and mixed crystalline / amorphous aluminosilicates as described in British Patent GB 1 470 250; and layered silicates as described in European Patent EP-B-164 514. Organic phosphate additives, for example, sodium orthophosphate, pyrophosphate and tripolyphosphate, may also be present, but on an environmental basis, these are no longer preferred. The aluminosilicates, whether used as stratification agents and / or incorporated into the bulk of the particles, can suitably be present in a total amount of 10 to 60%, and preferably in an amount of 5 to 50% by weight. The zeolite used in most commercial particulate detergent compositions is zeolite A. Advantageously, however, the maximum aluminum P zeolite (zeolite MAP) described and claimed in European patent EP-A-384 070 can also be used. Zeolite MAP is an alkali metal aluminosilicate of the P type having a silicon to aluminum ratio not exceeding 1.33, preferably not exceeding 1.15, and more preferably not exceeding 1.07. Organic additives that may be present include polycarboxylate polymers such as polyacrylates, acrylic / maleic copolymers, and acrylic phosphinates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono- di- and trisuccinates, carboximetilolxisuccinatos, iloximalonatos carboximet, dipicolinates, hydroxyethyliminodiacetates, alkyl- and alkenylmalonates and succinates; and salts of sulfonated fatty acids. A copolymer of maleic acid, acrylic acid and vinyl acetate is especially preferred, since it is biodegradable and thus environmentally desirable. This list is not intended to be exhaustive. Especially preferred organic additives are citrates, suitably used in amounts of 5 to 30%, preferably 10 to 25% by weight; and acrylic polymers, more especially acrylic / maleic copolymers, suitably used in amounts of 0.5 to 15%, preferably 1 to 10% by weight. The citrates can also be used at lower levels (for example 0.1 to 5% by weight) for other purposes. The additive is preferably present in the form of alkali metal salt, especially sodium salt. Suitably, the additive system may also comprise a crystalline, layered silicate, for example, Hoechst SKS-6, a zeolite, for example, a zeolite A and optionally an alkali metal citrate. The granular composition resulting from the process of the present invention may also comprise a particulate filler "(or any other component that does not contribute to the washing process) which suitably comprises an inorganic salt, for example sodium sulfate and sodium chloride. The filler may be present at a level of 5 to 7% by weight of the granular product. The present invention also encompasses a granular detergent product resulting from the process of the invention (before any post-dosing or the like). This product will have a bulk density determined by the exact nature of the process. If the process does not involve a pre-mixer to effect partial granulation, a final bulk density of 350 to 370 g / 1 can normally be expected. As mentioned above, the use of a premixer makes it possible for the final bulk density to be 350 to 650 g / 1 or 550-1300 g / 1, respectively, according to whether option (i) or (ii) is used . However, the resultant granular detergent products of the present invention are also characterized by their particle size ranges. Preferably, no more than 10% by weight has a diameter >; 1.4 mm and more preferably, no more than 5% by weight of the granules are above this limit. It is also preferred that no more than 20% by weight of the granules have a diameter greater than 1 mm. Finally, the granules can be distinguished from the granules produced by other methods by mercury porosimetry. The latter technique can not reliably determine the porosity of the individual non-agglomerated particles, but is ideal for characterizing the granules. A fully formulated detergent composition produced according to the invention may for example comprise the active detergent and the additive, and optionally one or more flow aids, a filler and other minor ingredients such as color, perfume, fluorescer, bleaches, and enzymes The invention will now be illustrated by the following non-limiting examples: Examples Example 1 In Examples I to V, the following formulation was produced using an SU 22 nozzle from Spraying Systems, operating at 2.5 or 5 bars of atomization air pressure: Sodium 24% by weight Sodium carbonate 32% by weight STPP 32% by weight Zeolite 4A 10% by weight Water 2% by weight In Example VI, the following formulation was produced using a SUE 25 nozzle of Spraying Systems, operating at an atomization air pressure of 3.5 bar: STP (Rhodiaphos H5) 63% by weight Sokolan CP5 9% by weight Water 28% by weight In Examples I to V, the rate of addition of the liquid (eg LAS) to the fluidization solids was varied from 130 to 590 g in -i In Example VI, the liquid addition rate (for example an aqueous solution of 20% CP5) to the fluidization STP powder was 400 gmin-1. In Examples I to VI, the average particle size d3.2 of these solids from 20 μm to 200 μm was, in all cases, 69 μm.

Table 1 records the influences on -the powders produced: Table 1 * average diameter d3,2 ** The n value of the Rosin Rammler distribution is calculated by adjusting the distribution of the particle size to a distribution to the nth power according to the following formula: where R is the cumulative percentage of the powder above a certain size D. Dr is the average granule size (corresponding to RRd) and n is a measure of the particle size distribution. Dr and n are Rosin Rammler's adjustments to a measured particle size distribution. A high value n means narrow distribution of the particle size and low values mean a wide distribution of the particle size.

Example 2 The droplet size was measured using a laser light scattering technique. LAS acid, at 55 ° C, was distributed through the nozzle at a speed of 90 kgh "1. At a distance of 32 cm from the tip of the nozzle, the droplet size d3.2 was measured in the center of the perfectly formed spray pattern For the atomization air pressures of 1, 2 and 3.5 bar, the droplet size d3.2 was measured at 51.4, 47.0 and 29.9 μm, respectively.

Claims (8)

1. A process for the production of a granular detergent product, the process comprises spraying droplets of a liquid binder to make contact with an initial, solid, particulate material, in a low cut granulator, where the average droplet diameter d3, 2 of the liquid binder is no greater than 2 times and preferably no greater than the average particle diameter d3, 2 of that fraction of the total solid initial material, having a particle diameter d3 # 2 from 20 μm to 200 μm, with the conditions that: (i) if more than 90% by weight of the solid initial material has an average particle diameter d3, 2 less than 20 μm, then the average particle diameter d3, 2 of the total solid, total material will be taken as 20 μm; (ii) if more than 90% by weight of the solid initial material has an average particle diameter d3, 2 greater than 200 μm, then the average particle diameter d3, 2 of the total solid initial material will be taken as 200 μm; (iii) the minimum droplet diameter d3.2 is 20 μm minimum, and (iii) the average particle diameter d3, 2 maximum of the initial solid material is less than 500 μm.

2. A process according to claim 1, wherein the average droplet diameter d3, minimum is 30 μ, preferably 40 μm.

3. A process according to any preceding claim, wherein the average droplet diameter d3, 2 maximum is 150 μm, preferably 120 μm, more preferably 100 μm and still more preferably 80 μm.

4. A process according to any preceding claim, wherein the low cut granulator is a gas fluidization apparatus.

5. A process according to any preceding claim, wherein the liquid binder comprises an acid precursor of an anionic surfactant and the initial solid material comprises an inorganic alkaline material.

6. A process according to any of the preceding claims, characterized in that a first portion of the liquid binder is mixed with the solid initial material in a premixer, to form a partially granular solid material, and then a second portion of the liquid binder is sprayed to enter in contact with the partially granular solid material in the low cut granulator, to effect complete granulation.

7. A process according to claim 6, "wherein the granular detergent product has a bulk density of 350 to 650 g / 1, wherein (a) 5-75% by weight of the total liquid binder is added to the premixer; (b) the remaining 95-25% by weight of the total liquid binder is added in the low cut granulator.

8. A process according to claim 6, wherein the granular detergent product has a bulk density of 550 to 1300 g / 1, wherein (a) 75-95% by weight of the total liquid binder is added in the premixer; and (b) the remaining 25-5% by weight of the total liquid binder is added in the low cut granulator.