DE1442992A1 - Process for the production of coarse-grained sodium di- and triphosphates of light bulk weight - Google Patents

Description

Chemical factory Budenheim _ ^ _- «-— ^ ^- ; May 30, 196; Rudolf, A. Oetker * ~~ · ~ * "~~ * "'P ^r * ^Kr ' / ^Wt -

Budenhe ^ m / Rhine λ T * \ |

"Process for the production of coarse-grained sodium di and tri phosphates of light bulk weight "

Increasingly, detergents and cleaning agents in the manner set hex that liquid or pasty surfactants voluminous phosphates, optionally mixed with other inorganic support materials are sprayed, wherein the surfactants are bound to the surface of these phosphate or minerals, so that a dry, trickling powder is produced. The voluminous phosphates are obtained by spray drying by calcining solutions of monophosphates (formerly called orthophosphates) in a spray dryer and then in the same apparatus or in a downstream second apparatus by heating them to higher temperatures in diphosphates (formerly called pyrophosphates) and triphosphates ( formerly also called tripolyphosphates) are transferred. These voluminous di- or triphosphates consist of small spheres with mean grain diameters of a maximum of 0.6-0.7 mm or of spherical fragments or even small, rather fragile aggregations of such, the grain size distribution usually being quite uneven. In addition, relatively heavy, coarse-grained products have already been produced by breaking and coarsely dissolving monophosphates calcined on the roller or di- and triphosphates produced therefrom, which, however, result in dense chunks without an inner surface. In another known method, in which water is added to a monophosphate calcinate in a trough mixer provided with stirring elements, heavy, coarse-grained products without internal surfaces are also produced. Even coarse-grained and voluminous phosphates could not yet be produced. However, such coarse-grained products with a large internal surface are particularly suitable for the production of detergents by the spray-on and spray-mixing process

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3 Particularly good, as it has a dry, trickling and coarse-grained end product result.

β has now been found that coarse-grained sodium di and / or triphosphates on.ηJedrigem bulk density can be prepared in such a manner that einkörniges Natriumraonophosphat with a Na ₂ O: 3 2oc ratio ^{of 1} »5-i1 with rapid, but gentle? Relative movement of the individual particles dt 4 to 30, preferably 7-20%, water are sprayed ^ with the mean .ere drop diameters at most 0.3 »preferably 0.2 mm, and this product with constant but gentle movement to temperatures between 250 and 550 ° is heated, the maximum temperature bur must be below the melting point in each case. Alkali triphosphates or triphosphates with a low bulk density are understood here to mean those which have a loosely measured bulk density of less than 600 g / preferably less than 500 g / l.

In this process, the fine individual particles are formed in the first stage irregularly shaped, coarse aggregates bound by crystal bridges, which in the second process stage with the release of the solution and constitutional water solidify further and convert into di- and triphosphate ·. This is caused by the water leakage further cavities, whereby the solidification takes place to form extremely stable, spongy-porous aggregates, which macroscopically roughly spherical Equal to shapes, but when magnified they are quite different, even if they reveal relatively closed shapes.

The prerequisite for carrying out the procedure is the existence of the Monophosphates used as starting material in fine-grained form. the Individual particles should be at least 90% grain size smaller than 0.3 and at least 50% grain diameter smaller than 0.1 mm. ' These monophosphates can be spray alinates where the type of atomization or post-treatment is individual particles so small diameter can arise. But it can also be a roller

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ialcinate can be brought to this fineness by grinding. I'm rougher Corn in the "starting material" makes the end product more difficult and also more slowly soluble.

However, it is used in the spray dryer, especially when spraying with single-fluid nozzles Lendes Calcinate obtained from mostly intact hollow spheres is used, then the diameter of the individual particles cloth above the limits mentioned above, since the speed of solution then is not adversely affected. The particle size then averages approximately between 0.05 and 0.5 min, preferably ), 1 and 0.3 are now », although there are also individual particles up to 0.7 mm can come. The balls are made according to the method according to the invention built up into very rapidly soluble, large aggregations, which have an extremely favorable ability to adsorb to surfactants and have moderate liquids and are particularly voluminous. In these grain sizes of up to 2.5 mm are also of practical interest in the end product.

e according to the Ua ^ O: PpOc ratio as well as duration and maximum temperature of the When heated, di- or triphosphates of different levels of absorption are produced or mixtures of these. You can optionally use a portion of the monophosphate used as starting material by fine-grained Replace i- or triphosphate, for example in the form that fine particles are sieved out of the end product can be used as returned goods, which is procedural Brings advantages. You can go up to about $ 80 with the addition of di- or riphosphate, but this is for reasons of calculation with the addition of condensed phosphates usually under $ 50 love. In principle, the process can also be carried out in such a way as to eat sodium di- or triphosphates in fine-grained form in accordance with the invention Wise are sprayed with water and the Sprühungspro-; kt is subjected to reheating. In this process, every-) ch the aggregation is not as stable and more fines remain

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tn product, quite apart from the fact that such an embodiment is un-. is economic. Instead of the calcined phosphates, in some cases Hydrates of low hydration level are used.

The amount of water sprayed on should be 4 to 30, preferably 7 to Ofo water, calculated on the starting phosphate. Too low · the water content is too few and too small aggregations, too high a water content gives larger clumps. A very fine misting of the water is an advantage; on each pail, the mean drop size should be at most 0.3 mm, preferably at most 0.2 mm. It is essential that the water be applied to the phosphate in a fine distribution, but in liquid form. Droplets that are too large lead to heavier and denser aggregates with a small internal surface. Applying the water in vapor form also gives poorer results; the aggregates are much smaller and less bound. The more suitable the spraying apparatus, the greater the yields of uniformly grained material that are obtained with relatively low amounts of water.

Instead of water, a solution of alkali monophosphate can advantageously also be sprayed on, it also being possible to use higher concentrations, such as, for example, a melt of Na ₂ HPO, 12 H ₂ O in its own crystal water. Apart from energy savings, the solutions of the monophosphates show particularly good agglomeration due to the rapid formation of crystal bridges. Such a product sprayed with a solution is also easier to handle during the subsequent heating for conversion into condensed phosphate. Solutions of condensed phosphates, in particular of di- or triphosphates, as well as mono- or polyphosphoric acid are also suitable for the purpose according to the invention. The Na ₂ O: P ₂ Oc ratio can be chosen as desired; In any case, it must be adjusted to the substrate to be sprayed in such a way that the desired Na ₂ OiP ₂ O ^ ratio is present in the 7 ', u! product.

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Some of the sodium can be replaced by Ki lium in the process according to the invention. The potassium can already be contained in the substrate - for example as potassium sodium monophosphate * , but it can also be introduced with the spray-on solution. The hygroscopic properties of the pure potassium di- and triphosphates set limits to the increase in the potassium content. A replacement of significantly more than 60 mol $ of Na ₂ O by KpO is therefore not possible if hygroscopic products are to be avoided.

It has also been found that the process according to the invention does so It is particularly advantageous if sieving is carried out before the heating, in particular the coarse fractions that occur during the spraying process are formed to a smaller part, will be separated: Also a separation of the fine parts remaining after spraying on can be beneficial. The coarse fractions can be a grinding or a force * are subjected to sieving, whereupon they are added back to the starting material, optionally also fed to the second process stage can. The finished product then usually no longer needs to be re-screened when the pre-screening is carried out? is the final bulk density with this procedure lower than without pre-screening, the proportion of the desired grain size, calculated on the amount of the starting material, is higher. The fine fractions are expediently with a sieve with 0.3 or 0.4 mm mesh size, the coarse parts with at least one Sieve with Q. 75 mesh size, but preferably a sieve with 1.5 or 2 mm mesh size, which then results in mean grain diameters of 1.2 to approx. 1.6 mm.

One will in general - especially in the case of continuous operation - carry out the heating after the spraying. Qualitatively, there is a certain storage and maturation time for the sprayed material Before heating, however, advantages: If-you can pre-spray the material heating for a few hours or overnight - generally between

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one and 24 hours - the bulk density of the end product is lower than when the freshly sprayed material is heated

The spraying can be carried out in various devices. The prerequisite is that the individual particles perform rapid but gentle relative movements, ie 'that they change their mutual position quickly and constantly, but without being exposed to greater pressure, greater pressure or friction, so that the spray formed during the loading On the one hand, aggregations are not compressed into dense structures and, on the other hand, they are not ground up again into painful proportions. Devices that do not contain relatively moving mixing elements, ie none that are moved independently of the container, are most suitable. Mixing apparatus with rapidly running, beating or pressing mixing tools are not suitable for the purpose according to the invention. In contrast, the spraying can be carried out with good success in rotating tubes or rotating drums, for example with the conical spray mixing drum according to German patent application C 23 451 IVa / i2g, which consists of a reaction drum that has the shape of a double cone with a common base circle has _f which rotates around the cone axis and inside which internals are arranged, which move the material back in the direction of the two cone tips with each rotation of the drum, and at one cone tip an opening for injecting a liquid, at the other cone tip if necessary has an opening for removing dust and, if necessary, a closable opening for loading and emptying on the common base circle of the two cones. The most favorable are those apparatuses in which the layer height of the material is low and as a result the same is not pressed through the overlying layers of material. As a result, a continuous procedure on the oscillation level according to German patent application G 26 943 IVa / i2g, in which the to spray one another, is particularly suitable for this purpose

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particles end over an approximately horizontal, preferably flat surface ».He move, which is limited on the long sides by vertical edges .st and the vibrations with frequencies in the direction of movement of the goods between 8 and 200 Hz. The individual particles of the Subiträta move upwards on this oscillation plane in small trajectory parabolas, so that the spray cone on constantly renewed material surfaces meets. There is no mechanical damage to the loop aggregations formed.

■ Finally, the Decanted granulating plates, with the size of the plate, the inclination and number of revolutions, the feed speed of the substrate and the spraying speed must be chosen so that no dense franulate, but only loose aggregations form. Insofar differentiated Here, too, the method of operation according to the invention differs from the bewitched Granulation process. This apparatus also has the advantage that it can be operated continuously.

The further heating of the sprayed material can e.g. in a rotary kiln, jiner rotary drum or a deck oven when using the jchwing level, if necessary, also on this itself. The heating temperatures should be higher than 250 °, preferably higher than 300 °, but never reach the melting point. Temperatures between 300 and 450 degrees are preferred. Here, too, there are stronger mechanical effects on the aggregations formed, e.g. by rubbing, bridging or squeezing, undesirable: these should be free and loose move against each other while being smeared by the heating gases, But avoid being pressed or rubbed in the process. Likewise, the Aggregations that occur during spraying during transport to heating equipment is not squashed or pressed, which is why Conveyor screws are less suitable for this than conveyor belts, chutes or spiral balancing conveyors.

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At the end, the granular, voluminous products are provided after cooling it has not already happened before the heating - subjected to sieving, with any still formed, excessively coarse fractions and also the Torment parts are separated.

The resulting in the inventive method voluminous and large-grain products show a high absorption capacity for liquids, especially surfactants with an oily or moderately pasty consistency, and quickly dissolve in water. Both the inventive phosphates itself, as well as the combinations with surfactants that can be produced from it, Emulsifiers, solvents and preservatives flow well and do not clump together. The novel products are as a result for the manufacture of many chemical-technical products, ideally suited as a raw material. You are under the microscope easily distinguished from spray-drying products while the latter from spheres or spherical shells or possibly small agglomerations consist of small balls or spherical shells, represent the invention Products are irregularly shaped, but large structures that have approximately the same dimensions in every direction and consist of a large number of small individual particles that are put together in such a way that cavities are left in between, which form the whole structure penetrate, so that one can speak of a spongy structure.

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Example 1?

A sodium ammonophosphate spray calcinate with a NapOiPpOc ratio from 2: 1, with the $ 65 grain sizes smaller than 0.075 now, $ 78 grain sizes smaller than 0.1 mm and 99.3 $ had grain sizes smaller than 0.3 mm, was in a rotating drum that was 0.52 m long, a diameter of 0.52 m and rotating at 20 revolutions per minute, sprayed with $ 25 water using a 1.6 mm two-substance nozzle and an air pressure of approx. 2 at U. ' The mean drop size was 20 / u.

The sprayed product was converted into Na ^ PgOy at a maximum material temperature of 360 ° in an electrically heated laboratory rotary tube 1.35 m long and 0.08 m inside width, rotating at 12 revolutions per minute. After cooling, the transfer product was sieved on sieves with mesh sizes of 1.5 mm and 0.3 mm and, after sieving, consisted of 29 »3 $ of grain sizes larger than 1.5 mm with a bulk density of 370 g / l, 34 _f 5 $ from grain sizes between 1.5 and 0.3 mm with a bulk density of 410 g / l and to 36.2 $ from grain sizes smaller than 0.3 mm with a bulk density of 490 g / l. If, on the other hand, the entire transfer product was subjected to forced sieving on a sieve with 1.5 mm mesh size and further sieving on a sieve with 0.3 mm mesh size, 54% of the total product as a grain fraction was between 1.5 and 0, 3 mm with a bulk density of 430 g / l and $ 46 with grain sizes of less than 0.3 mm and a bulk density of 500 g / l.

By sifting out fine material smaller than 0.3 mm from the sprayed material Sodium monophosphate could reduce the proportion of coarse material, i.e. the Fraction 1.5 to 0.3 mm grain size, can be increased with approximately the same bulk weights. V / urde namely from the sprayed with $ 25 water Sodium monophosphate sifted out the fine fraction smaller than 0.3 mm and only the portion of the product to be transferred accordingly

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the above description, which consisted of grain sizes larger than 0.3 mm (grain sizes larger than 1.5 mm were not available), in this way an end product was obtained which did not contain any grain sizes larger than 1.5 mm. The proportion of the sieve fraction was 1.5 mm to 0.3 mm $ 67 with a bulk density of 445 g / l. $ 33 were fine with a grain size of less than 0.3 mm and a bulk density of 445 g / l.

Example 2:

An oscillation plane according to patent application 0 26 943 IVa / i2g, which consisted of a 60 cm wide and 3.6 ι long aluminum sheet, which carried 6 cm high vertical edges on the long sides, was caused by rotating, off-center masses in the longitudinal direction in linear oscillations of 4 mm amplitude offset at a frequency of 25 Hz. Calcined disodium monophosphate 1 ^ 2HPO * was made from a bunker, from $ 59.6 through a 0.075 mm mesh screen, $ 72.8 through a 0.1 mm mesh screen and $ 99.1 through a 0 screen , 3 mm mesh size, placed on the vibrating chute, a layer thickness of 6 mm being set by means of a transverse bar. Approx. 15 $ water were sprayed on by means of 6 nozzles moved back and forth, the mean drop size being 130 Ai . The nozzles were each three side by side transversely to the working direction, with a 0.5 mm pressure nozzle in the middle and a 1.1 mm pressure nozzle on each side, which were subjected to 3.5 atmospheres of water pressure. The two rows of nozzles were 1.5 m both were moved back and forth mechanically in the working direction, covering a path of 16 cm was igt and with that

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in part of the material under this rod, another over the rod assed »

he sprayed material was divided into three parts:

a) was immediately, without sieving, by the one described in Example 1 Given rotary kiln,

b) after 16 hours of storage without sieving, through the given in example 1 rotary kiln,

c) was after 16 hours of storage through a sieve with 1.5 mm mesh size and the fraction with a Grain size smaller than 1.5 mm given by the rotary kiln described in Example 1,

> After heating to 400 ° in the rotary kiln, the following resulted

a .5 * b 5% 5 ok oat rush J >> 1.5 mm 38, Mon 43, * 50 Parts 0.3 - 1.5 mm (main
fraction) 51, ok 43, ok 45 g / l Parts <C0.3 mm 10 g / l 13th g / i 485 g / l Debris weight of the whole
Materials 580 g / l 510 g / l 360 Bulk weight of the main fraction 460 400

Example 3:

A further experiment was carried out with the apparatus described in Example 2, but this involved 2 rows of 3 nozzles each .lit 0.8 mm nozzle opening used at 3.5 atmospheres water pressure '. the the mean drop size was 140 / rev. 3 kg of that described in 'Example 2 ealined disodium monophosphates were mixed in

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used with 1.5 kg returned material from Example 2 as starting material. One third of the returned material consisted of ground coarse material the spray, two thirds of fine tetrasodium diphosphate, the after the transfer had passed a sieve with a gauge of 0.3 mm.

On the vibration level, there were screening devices behind the two rows of nozzles attached, which allowed first the coarse fractions with grain sizes over 1.5 mm and then the desired grain range take out between 1.5 and 0.3 or 0.2 mm. The fines remaining on the vibration plane after the first row of nozzles migrated to the second row of nozzles, after which in turn the desired grain area was removed through a mounted pair of sieves. The remaining torment was used again as return goods.

After the first row of sieves, 28% of the material used had ... grain sizes between 0.3 and 1.5 mm and were removed or , if another sieve was used, 41% of the material with grain sizes between 0.2 and 1, 5 mm. The two desired grain fractions contained 10.4 and 9 »0 $ spray water, respectively. After the second pass, another $ 23 or $ 34 of the material with the desired grit range was removed. The bulk weights of the fraction with the two grain sizes 1.5 mm to 0.3 mm and 1.5 mm to 0.2 mm were 428 and 455 g / l, respectively. After conversion into tetrasodium diphosphate at 400 ° in the rotary stirrer furnace described in Example 1, the bulk weights were 400 and 470 g / l, respectively.

Example 4:

In the same apparatus as in Example 3 with the same nozzle and screen arrangement, 5 kg of a calcined disodium phosphate Na ₂ HPO ^ prepared in the spray tower by atomizing with a single-fluid nozzle and drying in cocurrent were used as the starting material, which consists of intact hollow spheres with an average diameter

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of 0.2 mm. After transferring the fraction with grain sizes between 1.5 mm and 0.3 mm of the 17.7 $ spray water Spray product at 400 ° in the same rotary kiln as in Example 1 in tetrasodium diphosphate became grape-shaped particles obtained with a bulk density of 335 g / l.

Example 5?

5 kg sodium monophosphate Speühcalcinat with a NapOiPgOj - ratio of 1.6: 1 were placed on a rotating plate with a diameter of 1.1 m * who had an inclination of 45 ° to the horizontal and rotated at 20 revolutions per minute, sprayed with 10 $ water within 1 minute, the mean drop size was 120 / u. After spraying the plate rotated for another 3 minutes. The sprayed product was in the rotary tube described in Example 1 at 360 ° material temperature converted into sodium triphosphate. After cooling, the product became Forcibly sifted through a sieve with a mesh size of 1.5 mm and the fine material smaller than 0.3 mm through a second Separated sieving. The fines were mixed with the starting material and sprayed again with this. The sieving was carried out in the same way as in Example 1. The sieve fraction 1.5 to 0.3 mm, which accounted for $ 79 in the final product, had a Bulk density of 445 g / l. Before the transfer, the fine material with a grain size of less than 0.3 mm was made from the sprayed sodium monophosphate sifted out and only the coarse material used for transfer under otherwise identical conditions, this could be done with the same bulk weights the fraction of the fraction 1.5 to 0.3 mm to be increased to $ 94. The dissolution rate was 30 seconds.

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Example 6:

200 kg of disodium monophosphate spray calcinate with the in Example 1 reported properties were based on that described in Example 5 " rotating plate sprayed in batches with 6 $ water. The capacity of the plate was 8 kg of disodium monophosphate. Sprayed was with a 0.5 mm single-fluid nozzle corresponding to a throughput of 100 ml of water per minute and a medium drop size by 15OyU. The product was then after an interim storage of approx. H hours in a rotary tube of 6 in length and 0.6m of lights Width and a speed of rotation of 2.5 rpm at 360 ° G material temperature converted into tetrasodium diphosphate. The material throughput was approx. 150 kg starting phosphate per hour. After cooling, the product was passed through a sieve with a mesh size of T, 5 mm Forcibly sieved and the fine material with grain sizes smaller than 0.3mm separated by a second sieving. The fines were mixed with the starting material and fed back for spraying. the The sieve fraction 1.5 to 0.3 mm had a bulk density of 4-20 g / l a solution speed of 20 seconds. The fine material had a bulk density of 530 g / l and a dissolution rate of 30 Seconds on. Both fractions showed good flow behavior.

The rate of dissolution was determined as follows: In a test tube of approx. 40 ml content were successively added 0.4 g of substance · and ml aq. dist. filled. The jar was closed with a stopper, soiort swiveled around and moved evenly. The time until the substance dissolves gives a value which allows the dissolution times to compare different substances with one another.

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Claims (1)

atefltane requirements ι I ^1st Process for the production of coarse-grained sodium di'- and triphosjhaten of light bulk weight by transferring monophosphates) at temperatures below the melting point, characterized in that fine-grained sodium monophosphate with a MagOiPgOr ratio of 5 to 2: 1 with rapid but gentle relative movement of the individual -, little particles are sprayed with $ 4 to $ 30, preferably $ 7 to $ 20, of water, have an average droplet diameter of at most 0.3, preferably 0.2 mm, and this spray product is rubbed continuously, but gently, or Squeezing avoiding movement is heated to temperatures between 250 and 550 °. \ Method according to claim 1, characterized in that the fine-grained Sodium monophosphate for more than $ 90 consists of particles whose The grain diameter is less than 0.3 mm, and more than 50% of particles whose grain diameter is smaller than d, 1 mm. 5. The method according to claim 1, characterized in that the fine grain * - aige sodium monophosphate is obtained by spray drying and predominantly has the shape of hollow spheres with an average particle size between 3.05 mm and 0.5 mm, preferably between 0.1 mm and 0.3 mm. Φ. Method according to one of Claims 1 to 3, characterized in that The spray-on product was passed through a sieve, preferably before heating is screened off with a mesh size of 0.75 to 2 mm. 5. The method according to any one of claims 1 to 4, characterized in that that the sodium monophosphate, preferably before spraying with water, sodium di or triphosphate is added. i. Method according to one of Claims 1 to 5, characterized in that ate an aqueous solution of an alkali metal phosphate and / or phosphoric acid is used for spraying. COPY 8 0 9 8 1 3 / Π L 2 Q BAD ORIGINAL 7. Method according to one of Claims 1 to 6, characterized in that that part of the iNiatriuniphosphate is replaced by potassium phosphate. 8. The method according to any one of claims 1 to 7 / characterized in, that the preliminary product is stored for 1 to 24 hours after spraying before it is heated. 9. Method according to one of Claims 1 to 8, characterized in that that the spraying of the water takes place in a moving device that contains .no relatively moving mixing elements. 10. The method according to claim 9, characterized in that the spraying in a rotating drum, preferably a spray mixing drum, is made, which on the whole has the shape of a double cone with common Has a base circle that rotates around the cone axis, and in the interior of which fittings are arranged that occur with each rotation of the drum Move the product back towards the two cone tips, as well as an opening at one of the cone tips for injecting a liquid, if necessary, an opening for the discharge of at the other cone tip Dust and exhaust air and possibly on the common base circle of the two Cone has a closable opening for loading and emptying. 11. The method according to claim 9 »characterized in that the spraying is made on an oscillation plane, which consists of an approximately horizontal, preferably flat surface on the long sides is limited by vertical edges and carries out vibrations with frequencies between approximately 8 and 200 Hz in the direction of movement of the goods. 12. The method according to claim 9 »characterized in that the spraying is made on a granulating plate. copy 8 0 9 8 1 3 / Π U 2 0 ^ _{0R | G | NAL}