GB1583449A - Process and plant for the production of granules - Google Patents

Description

(54) PROCESS AND PLANT FOR THE PRODUCTION OF GRANULES (71) We, CIBA-GEIGY AG, a Swiss body corporate, of Basle, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a process and a plant for the productions of granules as well as to the granules obtained by the process.

It is known that granules are formed as a result of a mixing and tumbling agitation of the material in the presence of, or with the application of, small amounts of a liquid phase. See, e.g., the article by H. B. Ries: "Aufbaugranulierung" "Build-up granulation) in "Aufbereitungstechnik" (Preparation techniques) -- No. 11/1971 page 657 ff.

It has now been found that by adding excess of the liquid phase with subsequent drying of the granules, as a result of which the excess liquid phase is removed, there can be obtained granules which, compared with the granules obtained by the more conventional method, surprisingly have an improved mechanical stability, a more homogeneous particle size and an improved solubility or dispersibility. In this manner it is possible in particular to convert very dusty fine powder into a non-dusty or negligibly dusty granular form.

The present invention provides a process for preparing a solid granulate consisting of 45 to 99.5% by weight of an organic substance and 0.1 to 50% by weight of granulating assistant and the remainder moisture, which process comprises: a) applying a granulating liquid, containing 0.1 to 50 /O by weight relative to the granulating liquid of at least one granulating assistant which is a wetting agent, dispersing agent, binding agent or solubility improving agent, to a pulverulent organic substance, which is subject to a tumbling or rolling rotating movement, said granulating liquid being applied in an amount in excess of that amount of liquid which would provide equilibrium between the moisture content in the substance and that of the ambient air, the amount being from 5% to 300% by weight relative to the pulverulent substance; and b) subsequently drying the resulting moist granulate until its moisture content falls to or below said point of equilibrium to form said solid granulate.

The point of equilibrium between the moisture content of the substance and that of the air corresponds to the amount of moisture of the pulverulent substance expressed in percent of relative humidity of the atmosphere when the partial vapor pressure of the moisture of the pulverulent substance equals the partial vapor pressure of the ambient atmosphere. Thus by "ambient air" is meant the air of the atmosphere in the area in which the apparatus is placed.

As the pulverulent substance, any inorganic or organic substance is suitable, and either homogeneous substances or mixtures of substances can be subjected to the process.

The substances concerned include: dyes, pigments, optical brightners, or textile auxiliaries, pharmaceutical products, mixtures of active substances for the manufacture of tablets, pesticidal compositions, foodstuffs and food supplements such as coffee powder, milk powder or flour; starch and starch decomposition products such as dextrin; antimicrobics and bacteriostatics; animal feeds, herbicides, plant protection products; detergents, paper auxiliaries (e.g. sizing agents), photochemicals, leather chemicals, polymers, plastics additives, synthetic resin moulding compounds, explosives, building materials, coal, ores, catalysts, chemicals, fertilisers, intermediates for cement manufacture, starting materials for ceramic products and also raw materials for powder metallurgy.

By "dyes" are meant all possible classes, both coloristically and chemically, which are suitable for aqueous and organic application. Examples which may be mentioned are: basic dyes, acid dyes, sulphur dyes, vat dyes, mordant dyes, chrome dyes, disperse dyes and direct dyes, and the dyes can contain fibre-reactive groups in the molecule. It is to be understood that foodstuff dyes and, for example, leather dyes, are also included.

Suitable chemical classes of dyes are e.g. nitroso, nitro, monoazo, disazo, trisazo, polyazo, stilbene, carotenoid, diphenylmethane, triarylmethane, xanthene, acridine, quinoline, methine, thiazole, indamine, indophenol, azine, oxazine, thiazine, lactone, aminoketone, hydroxyketone, anthraquinone, indigoid and phthalocanine dyes, as well as 1:1- or 1:2-metal-complex dyes.

Suitable optical brightness, which are used for white tinting, can be of any class of brighteners; for example, stilbene compounds such as cyanuric derivatives of 4,4'diaminostilbene-2,2'-disulphonic acid or distyrylbiphenyls, coumarins, benzocoumarins, pyrazines, pyrazolines, oxazines, mono- or dibenzoxazolyl, mono- or dibenzimidazolyl compounds as well as naphthalic acid imides or naphthotriazole and v-triazole derivatives.

By "textile auxiliaries" are meant chemicals that are required in the processing of the various textile fibres into finished fabrics, such as raw-wool detergents, lubricants, sizing agents, milling agents, impregnating agents, preserving agents, finishing agents, desizing agents, kier-boiling agents, bleaching auxiliaries, dyeing auxiliaries such as dispersing agents and levelling agents, printing auxiliaries, carbonising auxiliaries, mercerising auxiliaries, preparations for producing resistance to creasing and to shrinking, and antistatic preparations.

Pesticidal compositions are in general known. They are used, for example, to destroy plant pests (e.g. fungicides, insecticides, acaricides, nematicides, molluscicides and rodenticides), and to prevent plant diseases.

Antimicrobics are antimicrobial substances which are intended to, or serve to, retard or prevent disadvantageous changes caused by microorganisms in foodstuffs.

Bactreriostatics are substances which inhibit or prevent the growth of bacteria.

By "detergents" are meant those substances which are composed of, for example, a) a synthetic detergent substance, a detergent basic material: b) a washing assitant (scouring additive); c) special additives such as sodium perborate, magnesium silicate, optical bleaching agents and wetting agents; and d) extenders. Both the detergents as such and the individual constituents can be granulated according to the invention.

Finally by "polymers" which can be granulated are meant macromolecular organic compounds which can be obtained by transformation of natural products or by synthesis, including plastics materials.

The pulverulent substance can be a pure substance or a diluted substance. It is also possible to use as the pulverulent substance a material that has already been spray dried.

The granulating liquid is preferably water or an organic liquid e.g. liquid alcohols, which can contain the specified additives in an amount of 0.1 to 50% by weight, relative to the granulating liquid. This "multicomponent" granulating liquid is a homogeneous solution or emulsion and can be obtained by introducing the additives to the granulating liquid and stirring this until it is homogeneous.

Suitable additives are, for example: as wetting and dispersing agents which can be anionic, cationic or nonionic, lignin sulphonate, dinaphthylmethanedisulphonic acid, sodium-dioctyl-sulphosuccinate, dibutylnaphthalenesulphonate, dodecylbenzenesulphonate, lauryl-pyridinium chloride, alkylphenoipolyglycol ether, stearyl-diphenyloxethyldiethylenetriamine and ethylene oxide adducts; as binders, dextrin, saccharose, starch, alginates, gelatine, glycerin, glycols, carboxymethylcellulose, polyvinylpyrrolidones, polyvinyl alcohols, a mixture of mineral sulphonic acid and an emulsifier (such as Essotex), polyoxypropylene glycols (block polymers of polyethylene oxide with polypropylene glycol), ethylene carbonate, or a mixture of paraffin oil and a non-ionic emulsifier; and, agents improving solubility, urea, tetramethylurea, caprolactan, polyethylene glycols. Other additives such as diluting agents, for example, sodium chloride and sodium sulphate can be added if desired.

The process is carried out by subjecting the pulverulent substance to a tumbling or rolling motion at, for example, room temperature, for example in a rotating drum (granulating drum). To this tumbling or rolling substance is then applied the granulating liquid, which is at a temperature of, say, 10 to 80"C, especially 15 to 25 C, for example, by means of spraying through a fine nozzle or through a coarser nozzle; in this respect one has to ensure that on the one hand the substance becomes uniformly wetted and that on the other hand the droplet diameter in the case of "fine-nozzle spraying" is preferably from 10 p to 30 ,,u in order to attain a homogeneous particle size of the granulate. (1 M = 1 micron = 1/1000 mm). The amount of granulating liquid added is in excess of that amount of liquid which would provide equilibrium between the moisture content in the pulverulent substance and that of the ambient air, with the amount of excess liquid thus applied, depending on the substance employed, being 5 to 300%, preferably from 5 to 40% by weight, relative to the amount of substance. This excess amount of liquid is subsequently dried off until the moisture content of the substance falls to or below the point of equilibrium between the moisture content of the substance and that of the air, e.g. in a drying apparatus, such as in a fluidised bed dryer. It will be appreciated that the point of equilibrium is affected by the temperature and pressure of the atmosphere i.e. the ambient air, at the time the process is conducted.

By this process, the agglomeration of the primary powder particles of the substance is initiated by the liquid applied and intensified by the tumbling or rolling movement resulting from the rotation of the drum.

The process is particularly suitable therefore for spray-dried powders, since by this process, one obtains an improvement of the dust behaviour, of the dissolving behaviour (wetting, solubility) and of the flowability. Furthermore, the process is particularly suitable for use with hygroscopic substances.

By virtue of the excess amount of granulating liquid, the surface of the particles of the substance becomes, in the ideal case, dissolved and a bonding action is thus created between the particles, so that generally there is no need to add binder to the granulating liquid.

The agglomerate strength is influenced mainly by the properties of the granulating liquid applied, and is based on a solid or liquid bridging bond between the primary particles of powder.

There can be obtained by the process according to the invention negligibly dusty to non-dusty granules having a particle size of 500 to 2000 ,u, which are characterised by a homogeneous, dimensionally stabile particle size, by a high mechanical strength, by their flowability and by their good dissolving behaviour, such as wetting, dispersibility and solubility rate. In particular, they form no significant dust during transport and processing.

The process according to the invention is particularly suitable for the production of granulates from substances which are sensitive to heat, since the process may be carried out under mild conditions. Especially sensitive substances may be dried for a longer time at a lower temperature.

The granules obtained by the process according to the invention can contain, besides solid and liquid, high-boiling additives which are applied with the granulating liquid, small proportions of granulating liquid, with the proportion of this being of the order of magnitude of the moisture content of the pulverulent starting materials.

The present invention also provides a plant suitable for producing granules, by means of build-up tumbling granulation, from pulverulent substances and granulating liquid, which comprises an inclined granulating drum rotatable about its inclined axis by a motor, having the upper (inlet) end of the drum connected to a powder-dosing device and having its lower (outlet) end connected, preferably via a lump crusher, to a dryer, spray nozzles fed from a granulating-liquid dosing device being arranged in the interior of the drum, the drum also being connected to a fan such that, in operation, a flow of air is generated which passes from the upper end to the lower end of the drum.

The known plants of this general type have various shortcomings. In particular, they cannot be used, or only to a very limited extent, for soluble, hygroscopic, finely pulverulent substances which in the moist condition are tacky and in some cases plastic.

Very fine hygroscopic particles, carried along by the spray, immediately become wet and stick to the nozzles and to the wall of the drum. A high solubility and/or hygroscopicity of the products or of the mixture constituents very quickly leads to the formation of a coating, especially in the fine spray zone, where any ambient moisture can prevail. The coating comes away from the wall of the drum and falls down onto the tumbling layer, a phenomenon which generally causes lumps to form. For example, soluble dyes having 5 to 15% residual moisture content (depending on the product) are semiplastic and tacky. The lumps occurring in this range of moisture content are difficult to break up.

It has been found, according to the present invention, that the product-specific and process-specific range of application of plants of the type described can be broadened in a very simple manner by connecting the granulating drum to a fan in such a way that inside the drum a flow of air passing from the inlet to the outlet can be generated.

By this measure alone, a considerable widening of the product-specific and processspecific range of application of the plant can be obtained. It has also been found that the range of application can be still further extended in particular by being able to adjust the angle of inclination of the granulating drum and/or by making the adjustability of the nozzles as great as possible and/or by using a specifically developed lump crusher.

This plant is particularly suitable for carrying out the process according to the invention, since this process operates with a relatively high granulating moisture content.

The plant according to the invention is further illustrated with reference to the accompanying drawings in which: Fig. 1: a schematic overall view of a typical plant according to the present invention; Fig. 2: a perspective detailed view in the direction of the arrow II and, at a larger scale, obliquely to the plane of the drawing of Fig. 1; and Fig. 3: a cross section along the line III--III of Fig. 1, likewise at a larger scale.

In the Figures, a powder-dosing device is denoted by PD; a granulating drum by GT; a granulating-liquid dosing device by FD; a lump crusher by KB; and a dryer by TR.

Granulating drum GT is pivoted and can be driven by a motor. The rotary speed is preferably infinitely variable within a range of 5 to 50 r.p.m. The inclination of the drum to the horizontal is selectively adjustable, preferably in a range of 1 to 5". The adjustability of the angle of inclination is indicated in the Figures 1 and 3 by a tablelike carrier 1 which can be adjusted and fixed in the desired positions around an axis 2. The granulating drum rests on two rollers 60 and 61 supported on this carrier, one of which can be driven by a motor which is not shown.

Powder-dosing device PD is of a conventional construction and comprises twq storage containers 3a and 3b, two metering screws 4a and 4b, as well as a dosing conveyor-type weigher 5. Outlet 6 of the dosing device PD discharges through a central aperture of an end cover plate 7 into the upper part of the granulating drum GT.

Granulating-liquid dosing device FD is likewise of conventional construction and comprises a storage container 8 and a dosing pump 9. From the dosing pump 9, a supply pipe 10 passes through a covering cap 11 to nozzles 12, 13, 14 and 15 arranged in the granulating drum GT.

The lump crusher KB is connected on the inlet side, by means of a bellows-like tubing or duct 16 to the granulate outlet of the covering cap 11 of the granulating drum GR. The outlet of the lump crusher discharges into product inlet 17 of the dryer TR.

The dryer TR is a se-called fluidised bed dryer of the usual construction having two air-inlet chambers and an obliquely directed vibrating movement of adjustable amplitude. The dryer TR is connected to an air preparation device LA, which likewise is conventionally constructed and which comprises, inter alia, a filter 18, a blower 19 and two heat exchangers 20a and 20b.

A screening chamber 22 is connected to the product outlet 21 of the dryer TR. A "good granules" container 24 is connected to fine-material outlet 23 located below sieve 22s (vibrating sieve) of the screening chamber. The cover or dome of the dryer is connected by way of a pipe 26 and a filter chamber 27 to a suction fan 70. The fine fractions are drawn off from the dryer through this pipe 26. They are retained in the filter chamber and fall through a funnel-shaped section 28 down into a container 29 connected to this chamber. A feed pipe coming from coarse outlet 25 of the screening chamber likewise discharges into this funnel-shaped section. Thus the grains which are too coarse or too fine are collected in container 29.

The connections between dryer TR, lump crusher KB and granulating drum GT, and the insertion of the dosing outlet 6 into the granulating drum, are so tight that, in consequence of the suction action of suction fan 70, an air flow of, say, 0.02 to 0.2 m/s can develop in the granulating drum.

As can be seen from Fig. 2, the granulating drum GT has at the lower end a relatively low circular flange 30 projecting inwards, which forms a kind of overflow for the product. This flange is exchangeable so that the height of the overflow can be easily changed. Cap 11 encloses the lower end of the drum in a dust-tight and, to a certain extent, gastight manner. The covering cap is provided on its front side with sliding doors 38a and 38b.

The nozzles 12 to 15 are located on a rod-shaped carrier 31 running substantially parallel to the axis of the granulating drum, which, for its part, is secured by means of holder inside the cap 11. This holder renders possible a universal adjustment, indicated by the arrows X, Y and Z, of the nozzles in the longitudinal direction (X), in the vertical direction (Y) and with respect to the angle (Z). For this purpose, the holder comprises a structural member 40 having two clamps 32 and 33 perpendicular to each other, of which the one (32) is mounted on a rod 34, which is secured vertically on the cap, in such a way that this clamp is slidable and fixable; and the other (33) is mounted on a second rod 35 which runs parallel to the longitudinal axis of the rod-shaped nozzle carrier 31 and which is rigidly connected to this by a structural member 36. The clamp 32 makes possible the height adjustment Y, and the clamp 33 the longitudinal and angular adjustments X and Z.

The spray nozzles 12 to 15 are connected by way of the collector 37 to the granulating-liquid feed pipe 10. This collector has for each spray nozzle a respective valve 12v, 13v, 14v or 15v. The spray nozzles are preferably single-component discharge pressure nozzles having swirl vanes and an aperture diameter of 0.1 to 1.0 mm.

The swirl vanes are exchangeable so that the,spray-cone angle is adjustable.

As is shown by Fig, 3, the granulating drum is provided on the inside with ribs 41 parallel to the axis. The height of these ribs is preferably about 20 mm. A protecting sheet 42 is arranged rooflike above the row of nozzles 12 to 15. The sheet 42 and the nozzle carrier 31 are connected to a vibrator 43.

As can be seen from Fig. 2, the lump crusher KB consists of a screening drum 50 driven by means of a motor 51, which screening drum is enclosed underneath with clearance by a trough-shaped sieve 52. This double-sieve arrangement is located in the lower part of a funnel-shaped housing 53, with the lower sieve 52 being fixed at its two edges, firmly but easily replaceable, to the walls of the housing. The distance between the two sieves 50 and 52 is freely adjustable and is preferably 5 to 15 mm. The speed of the screening drum 50 is adjustable from 40 to 120 r.p.m. The mesh width of each of the two sieves is preferably about 8 mm. The two sieves are preferably arranged according to the drawing in such a way that their meshes are offset by an angle preferably about 45 , to one another.

The mode of operation of the plant described is as follows: The plant can operate continuously. The product to be granulated is continuously fed from the powder-dosing device PD through its outlet 6 into the upper end of the rotating granulating drum GR.

From the liquid-dosing device FD there is simultaneously sprayed, likewise continuously, granulating liquid through the nozzles 12 to 15 inside the granulating drum.

The fan 70 is adjusted in such a way that there is created in the granulating drum (via 27-2TR-17-KB-16-11) a flow of air having a velocity of about 0.02 to 0.2 m/s.

The powder dosing and the liquid dosing, the rotary speed of the granulating drum and its angle of inclination, as well as the number of effective spray nozzles and their position, direction of spray and spray cone, are adjusted to suit the material to be granulated. Furthermore, the characteristics of the granulation can be influenced by the height of the overflow 30 (Fig. 2).

The granulating process can be best seen from Fig. 3. The vibrator 43 is switched on during the granulating process, and by this means the formation of crusts on the protecting sheet 42 and on the nozzle carrier 31 is largely avoided.

The moist granules, formed as a result of build-up granulation in the granulating drum, fall down into the lump crusher KB. Any lumps present are crushed therein, with relatively low shearing forces, between the sieves 52 and 50. The product falls from the lump crusher into the dryer TR.

In the dryer TR, the fine fractions at the top are carried along during the drying process with the exhaust air to the filter 27. The dryer acts additionally therefore as an air sifter. The air-flow conditions in the hood of the dryer or in the dome are of decisive importance with regard to sifting. The under-pressure in the dome of the dryer is adjusted to 50 to 70 Nm-2. At the dryer outlet 21, the granules in the screening chamber 22 are separated into "good granules" and "oversize granules". The "good granules" fall into the container 24, and the "oversize granules" into the container 29.

The fractions which are too fine also pass into container 29 via 2627--28.

The following Examples further illustrate the process according to the invention employing a discontinuous laboratory apparatus. The temperatures are given in degrees Centigrade.

The substances given in the Examples are employed, where not specified otherwise, in the usual commercial form containing the usual diluents. The water content of the moist granules consists of the amount of liquid which has been applied by spraying in addition to the moisture content of the starting substance.

Example 1.

100 g of the dry, non-dusty dye of the formula

is placed as powder into an agglomerating drum of 20 cm diameter and 20 cm in length, and the drum is then rotated (25 r.p.m.).

50 g of a granulating liquid of the composition: 85% of water, 10% of polyoxypropylene glycol and 5% of an adduct of stearyldiphenyloxethyldiethylenetriamine and ethylene oxide is mixed together in a beaker and stirred with a magnetic stirrer for 10 minutes to form a homogeneous solution.

The granulating liquid is smoothly fed into the spray nozzles by means of a squeezed tube pump. With a throughput of liquid of 6 g/minute, the two-component nozzle is adjusted to give a droplet size of 10 to 100 ,tri with a suitable spray cone. The nozzle is inserted through the lateral drum opening into the drum, and the agitated dye powder is uniformly sprayed for 1.7 minutes. The nozzle is subsequently removed from the drum, and the moistened, agglomerated powder is aftertumbled for about one minute further.

110 g of the moist agglomerate is transferred to the fluidised bed dryer and dried at an air temperature of 90 to 100" for 4 minutes. The rate of flow in the empty tube is about 0.4 m/sec. at an air temperature of 100 . Any fine particles present or fine powder formed during drying is separated in the cyclone separator located on the output side and can be fed back for subsequent agglomeration. The moisture content of the agglomerate leaving the drum was 9.5%, whereas the dried agglomerated product has a water content of 1 %.

There is obtained about 100 g of negligibly dusty, flowable and dimensionably stable dye granules of the composition: 97.5 % of the above dye, 1.0% of polyoxypropylene glycol, 0.5 % of an adduct of stearyldiphenyloxethyldiethylenetriamine and ethylene oxide, and 1.0% of water, which granules retain on storage in air their nature and shape.

Compared with the dye powder, the dye granules have better wettability and hence also have a good dissolving capacity.

Granules of the composition given in the following Examples 2 to 16 are obtained by using the constituents and operating conditions stated in these Examples, but otherwise employing the procedure according to Example 1.

Example 2.

Substance: dye mixture of the dyestuffs of the formulae

amount of mixture used: 100 g; granulating liquid: composition: 75 % by weight of water, 25% by weight of a mixture of paraffin oil and nonionic emulsifier; amount: 9 g; length of time in drum: 2.5 minutes; water content of the moist granules: 8.4%; drying temperature: 90 to 100 ; length of time in dryer: 3 minutes; composition of granules: 96.0% by weight of dye mixture, 2.2% by weight of a mixture of paraffin oil and nonionic emulsifier, 1.8% by weight of water.

Example 3.

Substance: dye of the formula

amount of dye used: 100 g; granulating liquid: composition: 40% by weight of dextrin, 10% 10% by weight of polyoxypropylene glycol, 50% by weight of water; amount: 30 g; length of time in drum: 6 minutes; water content of the moist granules: 13.4%; drying temperature: 90 to 100 ; length of time in dryer: 7 minutes; composition of granules: 84.0% by weight of dye, 10.1% by weight of dextrin, 2.5 % by weight of polyoxypropylene glycol, 3.5% by weight of water.

Example 4.

Substance: dye mixture of

amount of dye mixture used: 100 g; granulating liquid: composition: 95% by weight of water, 5% by weight of lignin sulphonate; amount: 30 g; length of time in drum: 6 minutes; water content of the moist granules: 25.0%; drying temperature: 90 to 100 ; length of time in dryer: 11 minutes; composition of granules: 93.0% by weight of dye mixture, 1.2% by weight of lignin sulphonate, 5.8% by weight of water.

Example 5.

Substance: dye of the formula

amount of dye used: 300 g; granulating liquid: composition: 70% by weight of water, 20% by weight of dextrin, 10% by weight of a mixture of mineral sulfonic acid and emulsifier; amours: 90 g; length of time in drum: 16 minutes; water content of the moist granules: 17.4%; drying temperature: 100 to 1200; length of time in dryer: 20 minutes; composition of granules: 90.4% by weight of dye, 5.4% by weight of dextrin, 2.7% by weight of a mixture of mineral sulphonic acid and emulsifier, 1.5% by weight of water.

Example 6.

Substance: dye of the formula

amount of dye used: 100 g; granulating liquid: composition: 65% by weight of water, 35% by weight of a mixture of mineral sulphonic acid and emulsifier, amount: 1S g; length of time in drum: 3.5 minutes; water content of the moist granules: 13.8%; drying temperature: 90 to 110 ; length of time in dryer: 4 minutes; granulating composition: 92.5% by weight of the dye, 4.9% by weight of a mixture of mineral sulphonic acid and emulsifier, 2.6% by weight of water.

Example 7.

Substance: d

Example 8.

Substance: dye of the formula

amount of dye used: 500 g; granulating liquid: composition 70% by weight of water, 20% by weight of dextrin, 5% by weight of polyvinyl alcohol, 5% by weight of a mixture of mineral sulphonic acid and emulsifier, amount: 240 g; length of time in drum: 20 minutes; water content of the moist granules: 26.7 S,; drying temperature: 100 to 1200; length of time in dryer: 28 minutes; composition of the granules: 85.2% by weight of dye, 8.2% by weight of dextrin, 2.1% by weight of polyvinyl alcohol, 2.1% by weight of a mixture of mineral sulphonic acid and emulsifier, 2.4% by weight of water.

Example 9.

Substance: dye of the formula

amount of dye used: 500 g; granulating liquid: composition: 80% by weight of water, 20% by weight of a mixture of mineral sulphonic acid and emulsifier, amount: 125 g; length of time in drum: 20 minutes; water content of the moist granules: 20.0%; drying temperature: 90 to 1000; length of time in dryer: 18 minutes; composition of the granules: 93.0% by weight of dye, 4.7% by weight of a mixture of mineral sulphonic acid and emulsifier, 2.3 by weight of water.

Example 10.

Substance: dye of the formula

amount of dye used: 100 g; granulating liquid: composition: 70% by weight of water, 10% by weight of a mixture of mineral sulphonic acid and emulsifier, 20% by weight of dextrin; amount: 36 g; length of time in drum: 11 minutes; water content of the moist granules: 21.3%; drying temperature: 100 to 1200; length of time in dryer: 5 minutes; composition of the granules: 84.3 % by weight of dye, 6.1% by weight of dextrin, 3.0% by weight of a mixture of mineral sulphonic acid and emulsifier, 6.6% by weight of water.

Example 11.

Substance: dye composed of the condensation of p-nitrotoluenesulphonic acid with sodium hydroxide solution; amount of dye used: 100 g; granulating liquid: composition: 75% by weight of water, 20% by weight of dextrin, 5% by weight of a mixture of mineral sulphonic acid and emulsifier, amount: 30 g; length of time in drum: 7 minutes; water content of the moist granules: 19.8%; drying temperature: 110 to 1200; length of time in the dryer: 5 minutes; composition of the granules: 91.6% by weight of dye, 5.5% by weight of dextrin, 1.4% by weight of a mixture of mineral sulphonic acid and emulsifier, 1.3% by weight of water.

Example 12.

Substance: optical brightener of the formula

amount of optical brightener used: 100 g; granulating liquid: composition: 80% by weight of water, 20% by weight of alkylphenolpolyglycol ether amount: 42 g; length of time in drum: 8 minutes; water content of the moist granules: 25.9%; drying temperature: 90 to 110 ; length of time in dryer: 7 minutes; composition of granules: 87.8% by weight of optical brightener, 7.4% by weight of alkylphenolpolyglycol ether, 4.8% by weight of water.

Example 13.

Substance: (plastics additive)

4 ' tert. -C4li9 amount of substance used: 100 g; granulating liquid: composition: 80% by weight of water, 20% by weight of paraffin oil; amount: 30 g; length of time in drum: 6 minutes; water content of the moist granules: 19.7%; drying temperature: 90 to 100 ; length of time in dryer: 5 minutes; composition of the granules: 92.9% by weight of the above substance, 5.6% by weight of paraffin oil, 1.5% by weight of water.

Example i4.

Substance: dye of the formula

amount of dye used: 500 g; granulating liquid: composition: 70% by weight of water, 20% by weight of dextrin, 10% by weight of a mixture of mineral acid and emulsifier; amount: 115 g; length of time in drum: 20 minutes; water content of the moist granules: 20.0%; drying temperature: 65 to 750; length of time in dryer: 18 minutes; composition of the granules: 90.5% by weight of dye, 4.6% by weight of dextrin, 2.3% by weight of the mixture of mineral acid and emulsifier 2.6% by weight of water.

Example 15.

Substance: dye of the formula

amount of dye used: 500 g; granulating liquid: composition: 50% by weight of water, 50% by weight of ethylene carbonate; amount: 70 g; length of time in drum: 13 minutes; water content of the moist granules: 10.3 ,(, drying temperature: 50 to 60 ; length of time in dryer: 16 minutes; composition of the granules: 84.4% by weight of dye, 6.0% by weight of ethylene carbonate, 7.6% by weight of water.

Example 16.

Substance: dye of the formula

amount of dye used: 300 g; granulating liquid: composition: 50% by weight of water, 50% by weight of ethylene carbonate; amount: 55 g; length of time in drum: 10 minutes; water content of the moist granules: 17.3 /ó; drying temperature: 60 to 70 ; length of time in dryer: 14 minutes; composition of the granules: 85.9% by weight of dye, 7.9% by weight of ethylene carbonate, 6.2% by weight of water.

Example 17.

Substance: dye mixture of the formulae

amount of dye used: 500 g; granulating liquid: composition: 60% by weight of water, 30% by weight of alkylphenol polyglycol ether, 10% by weight of a mixture of paraffin oil and nonionic emulsifier; amount: 33 g; length of time in drum: 6.5 minutes; water content of the moist granules: 6.9%; drying temperature: 70 to 80 ; length of time in dryer: 8 minutes; composition of the granules: 96.6% by weight of dye, 1.9% by weight of alkylphenol polyglycol ether, 0.7% by weight of the mixture of paraffin oil and nonionic emulsifier, 0.8% by weight of water.

WHAT WE CLAIM IS:- 1. A process for preparing a solid granulate consisting of 45 to 99.5% by weight of an organic substance and 0.1 to 30% by weight of granulating assistant and the remainder moisture, which process comprises: a) applying a granulating liquid, containing 0.1 to 50% by weight relative to the granulating liquid of at least one granulating assistant which is a wetting agent, dispersing agent, binding agent or solubility improving agent, to a pulverulent organic substance, which is subjected to a tumbling or rolling rotating movement, said granulating liquid being applied in and amount in excess of that amount of liquid which would provide equilibrium between the moisture content in the substance and that of the ambient air, the amount being from 5% to 300% by weight relative to the pulverulent substance; and b) subsequently drying the resulting moist granulate until its moisture content falls to or below said point of equilibrium to form said solid granulate.

2. A process according to claim 1, wherein the granulating liquid is water.

3. A process according to claim 1 or 2, wherein the granulating liquid has a temperature of 10 to 800C.

4. A process according to claim 3 wherein the granulating liquid has a temperature of 15 to 25"C.

5. A process according to any one of claims 1 to 4, wherein the granulating liquid is finely sprayed through a nozzle onto the substance being subjected to the rotating movement.

6. A process according to any one of the preceding claims in which the granulating assistant is lignin sulphonate, an alkylphenolpolyglycol ether or an adduct of stearyl

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (30)

**WARNING** start of CLMS field may overlap end of DESC **. Example 17. Substance: dye mixture of the formulae amount of dye used: 500 g; granulating liquid: composition: 60% by weight of water, 30% by weight of alkylphenol polyglycol ether, 10% by weight of a mixture of paraffin oil and nonionic emulsifier; amount: 33 g; length of time in drum: 6.5 minutes; water content of the moist granules: 6.9%; drying temperature: 70 to 80 ; length of time in dryer: 8 minutes; composition of the granules: 96.6% by weight of dye, 1.9% by weight of alkylphenol polyglycol ether, 0.7% by weight of the mixture of paraffin oil and nonionic emulsifier, 0.8% by weight of water. WHAT WE CLAIM IS:-

1. A process for preparing a solid granulate consisting of 45 to 99.5% by weight of an organic substance and 0.1 to 30% by weight of granulating assistant and the remainder moisture, which process comprises: a) applying a granulating liquid, containing 0.1 to 50% by weight relative to the granulating liquid of at least one granulating assistant which is a wetting agent, dispersing agent, binding agent or solubility improving agent, to a pulverulent organic substance, which is subjected to a tumbling or rolling rotating movement, said granulating liquid being applied in and amount in excess of that amount of liquid which would provide equilibrium between the moisture content in the substance and that of the ambient air, the amount being from 5% to 300% by weight relative to the pulverulent substance; and b) subsequently drying the resulting moist granulate until its moisture content falls to or below said point of equilibrium to form said solid granulate.

2. A process according to claim 1, wherein the granulating liquid is water.

3. A process according to claim 1 or 2, wherein the granulating liquid has a temperature of 10 to 800C.

4. A process according to claim 3 wherein the granulating liquid has a temperature of 15 to 25"C.

5. A process according to any one of claims 1 to 4, wherein the granulating liquid is finely sprayed through a nozzle onto the substance being subjected to the rotating movement.

6. A process according to any one of the preceding claims in which the granulating assistant is lignin sulphonate, an alkylphenolpolyglycol ether or an adduct of stearyl

diphenyl oxethyldiethylene triamine and ethylene oxide.

7. A process according to any one of claims 1 to 5 in which the granulating assistant is a polyvinyl alcohol, a mixture of mineral sulphonic acid and an emulsifier, a polyoxypropylene glycol, ethylene carbonate or a mixture of paraffin oil and a nonionic emulsifier.

8. A process according to any one of the preceding claims, wherein the pulverulent substance is a dyestuff.

9. A process according to any one of claims 1 to 7 wherein the pulverulent substance is a pigment, an optical brightener, a textile auxiliary, a synthetic detergent, a plastics additive or a polymeric substance.

10. A process according to any one of claims 1 to 7 wherein the pulverulent substance is an animal feed, a pesticide or a plant protection product.

11. A process according to any one of claims 1 to 7 wherein the pulverulent substance is a pharmaceutical product, an antimicrobic or bacteriostatic substance.

12. A process according to any one of claims 1 to 7 wherein the pulverulent substance is a herbicide.

13. A process according to any one of claims 1 to 11, wherein the amount of granulating liquid applied to the substance is such that the amount of liquid added is 5 to 40% by weight, relative to the amount of substance.

14. A process according to claim 1 substantially as described in any one of the Examples.

15. Granulates whenever prepared by a process as claimed in any one of claims 1 to 12 and 14.

16. Granulates whenever prepared by a process as claimed in claim 13.

17. A plant suitable for producing granules from a pulverulent substance and a granulating liquid which comprises an inclined granulating drum rotatable about its inclined axis, having its upper end connected to a powder-dosing device and its lower end connected to a dryer, spray-nozzles fed from a granulating-liquid dosing device being arranged in the interior of the drum and the drum being associated with a fan in such a way that, in operation, a flow of air is generated which passes from the upper end to the lower end of the drum.

18. A plant according to claim 17 in which the lower end of the drum is connected via a lump crusher to the dryer.

19. A plant according to claim 18 in which the fan is connected with its suction side to the dryer, and the connections between dryer, lump crusher and granulating drum are sufficiently tight to ensure that, in operation, an adequate flow of air can be generated.

20. A plant according to any one of claims 17 to 19 in which, in operation, the velocity of the flow of air inside the granulating drum is adjustable within a range of 0.02 to 0.2 m/sec.

21. A plant according to any one of claims 17 to 20 in which the angle of inclination of the granulating drum is adjustable.

22. A plant according to any one of claims 17 to 21 in that the spray nozzles are mounted on a rod-shaped carrier, which runs substantially parallel to the axis of the granulating drum, the carrier being adjustable in a rotary direction around its longitudinal axis.

23. A plant according to claim 22 in which the nozzle carrier is adjustable in the direction of its longitudinal axis.

24. A plant according to claim 22 or 23 in which the nozzle carrier is adjustable in a direction perpendicular to its longitudinal axis.

25. A plant according to any one of claims 17 to 24 in which the amounts fed to the nozzles from the dosing device are adjustable individually and/or in groups.

26. A plant according to any one of claims 18 to 25 in which the lump crusher is formed by two sieves which are arranged at a distance from each other and which are movable, by means of a motor, relative to each other, such that the material to be crushed can be fed between the two sieves.

27. A plant according to claim 26 in which the distance between the two sieves is 3 to 15 mum.

28. A plant according to claim 26 to 27 in which one sieve is fixed and the other is formed by a rotatable cylinder.

29. A plant according to claim 28 in which the rotary speed of the sieve which can be driven is adjustable.

30. A plant according to claim 17 substantially as described with reference to any one of Figures 1 to 3 of the accompanying drawings.