FI72433C - FOERFARANDE FOER FRAMSTAELLNING AV VATTENHALTIGA, ICKE SEDIMENTERANDE DISPERSIONER, SAOSOM KONSTGOEDSELSUSPENSIONER. - Google Patents

Description

72433

Method for preparing aqueous non-sedimentable dispersions, such as artificial fertilizer suspensions

The invention relates to a process for the preparation of aqueous, non-sedimentable dispersions, such as artificial fertilizer suspensions, by dispersing solid particles in water, which process is characterized in that 10 starch and carbamide in the form of a product.

It is known that sol particles of the order of colloids sediment very slowly, thus adjusting the sedimentation equilibrium. The particles of the sus-15 suspension, which represent a coarser order of magnitude, sediment relatively quickly if their density is higher than that of the medium (Erdey-Gruz, T.-Schay, Cs .: Theoretische physikalische Chemie, Tankönyvkiadö, Budapest, 1964, pp. 226 - 233).

20 If both colloids and coarser particles are present in the systems, the coarser particles, which co-sediment relatively quickly, will bypass the smaller particles, they may accumulate with them and finally sediment in a way that is completely uncharacteristic of the small particles. at high speed, due to so-called orthokinetic coagulation (Dr. Buzägh A .;

Praktikum der Kolloidik, Textbook Publisher, Budapest, 1962, 30 pp. 143 - 149) -

Much of the industrial process aims to produce highly sedimentable systems, especially for the separation of materials with a solid and liquid aggregate state, such as in the dewatering of various sludges or in the sheeting of the paper industry. In the second part of industrial processes, the aim is to increase stability, to prevent sedimentation, e.g. in the preparation of drilling muds for the production of crude oil, in the preparation of various emulsions or when the transport of dispersions is assigned to storage. Typical examples of this are the preparation of filler-5 suspensions in the paper industry, the stabilization of paraffin, bitumen or also various plant protection emulsions for various purposes, and also the preparation of various artificial fertilizer dispersions.

From an economic point of view, the production of artificial fertilizers is currently one of the most important and therefore also the most dynamically developing areas in terms of stabilizing suspensions. For this reason, the principles, practice, and detailed issues of stabilization will be elucidated using, as an example, suspending artificial-15 wounds.

The storage and transport of various fertilizers in powder form involves a great deal of waste, and the unevenness in their application is always harmful; the application of kei-20 fertilizers containing various active substances is possible only in several stages of work. These problems can be avoided with suspensions prepared from artificial fertilizers containing various active substances, when they do not show any sedimentation which interferes with the work steps used, from the time of manufacture, storage, application to application.

The designation of suspended fertilizers is misleading. Undoubtedly, the solid fertilizer components used in the manufacture belong to the coarse dispersion range 30. The size and quality of the particles in the saturated solution of the components have a complex picture due to various interactions in the solution, double salt formation events, particle separation, etc. The quality or particle size of the particles in these systems has not been underserved. scientifically detailed studies; for this reason, these systems have been collectively referred to as dispersions without analyzing particle size. This definition allows the presence of particles belonging to both colloidal and coarse dispersive orders of magnitude, separately or in common.

Electrolytes are used in the suspensions to stabilize them against sedimentation in the usual way. These create electrostatic repulsive forces between the particles, thus preventing them from aggregating. Of course, this method cannot be used for a medium consisting of a strong electrolyte solution of fertilizer dispersions.

So-called macromolecular colloids can also be used to stabilize the dispersions, which increase the viscosity of the medium, thus making it more difficult to sediment the particles, but also enveloping the particles enveloped, which likewise prevents agglomeration. Gelatin, carboxymethylcellulose, polyvinyl alcohol, casein, ligninsulfonic acid or its derivatives, sorbitol, glucose, etc. can be used for this purpose.

To stabilize suspended artificial fertilizers, synthetic silicates, various silicic acid derivatives, colloidal silicate sols, magnesium aluminum silicates have been proposed; further use is made of natural silicates, such as bentonite, illite, attapulgite, etc. belonging to clay minerals, etc. Phosphate-based dispersants are optionally also used in addition to clay materials. In addition to dispersants and stabilizers, the importance of the effect of mechanical comminution is also emphasized. The state of the art in this regard is described, for example, in Buzdgh's Praktikum der Kolloidik 35 (Takönyvkiadö, Budapest, 1962, pp. 119-125, 1-3-1-19 and 176-199), further in DE patent 1,667,798 and U.S. Pat. in patent revision 3,579,321.

11 72433

The presented methods can provide relatively good stability, however, in such stabilized systems it is necessary to rehomogenize the already sedimented components in practice in most cases by occasional mixing.

Another problem is the relatively high cost of industrial products due to the need for materials and energy. Natural, or correspondingly different industrial by-products, on the other hand, have a large variation in quality as a means of stabilization. Possibly, the value of a method that has been found to be useful may decrease when the stabilizer has a chemical composition foreign to the soil substances.

The object of the invention is to provide a method which makes it possible to stabilize suspensions with abundantly available, homogeneous and relatively inexpensively available substances which can be used without special chemical modification and which do not in principle differ from the natural components of the soil.

The invention is based on the finding that this task can be solved by means of starch and urea. Surprisingly, it was found that the rapidly sedimenting starch and urea per se not only remain sedimented in one water, but also prevent the sedimentation of the solid particles of the dispersion.

This finding is all the more surprising for this reason because, according to the literature (Handbuch der Papier-industrie, Chefredakteur: György Vämos, Muszaki Könyvkiadö, Budapest, 1980, pp. 120 - 122 and 1 ^ 3), the starch normal-30 list is converted to an oxidizing, enzymatic base or a non-sedimentable system due to the decomposition of the acid, and the product thus obtained is again not known as a stabilizer, but precisely as a coagulant, clarifier or sediment.

Accordingly, the invention proceeds by adding starch and urea, either separately or in the form of a pre-prepared mixture, to water or an aqueous medium or to a dispersion already containing solid particles before preparing the dispersion.

5 The amount of starch used for stabilization is 1-50 by weight- $, preferably 2-10 by weight-? The amount of urea is at least as high as that of the starch, but not more than fifty times, preferably 2 to 10 times, that of the starch.

The starch can preferably be used in uninsulated form, in the form of natural substances containing starch.

The starch and urea can preferably be used in the form of a dry mixture.

The process according to the invention produces a non-sedimenting, well-flowing and easy-to-shake system from mixtures of different material qualities which dissolve in different ways in water and consist of inorganic and / or organic compounds.

20 The method thus meets a number of needs at a higher level than the prior art: - It has been possible to stabilize suspensions with substances which are not foreign to the natural components of the soil, living organisms.

25 - The method is not limited to a small group of different materials, but rather ensures the required stability when using dispersed parts with the widest possible range of chemical compositions.

30 - In the case of artificial fertilizer suspensions, another stabilizing component, the urea, must be regarded as their natural component.

- It will make it possible to expand the use of starch, which is an important product of the agro-industrial industry.

6 72433 - It does not require the isolation of starch from its natural state, it also has an effect on the use of powdered products of various starchy vegetable substances, e.g. cereals, etc.

Other details of the method according to the invention and the effects obtained by them will be explained in more detail by means of the following working examples.

Comparative Example 1 40 g of starch was dispersed by continuous stirring in 500 ml of water. The dispersion was filled into a 250 ml sedimentation cylinder with a 2.5 ml division in the range of 100 to 250 ml. The volume of sedimented material was read after 15 l, 2 and 24 hours, then after 24 hours of sedimentation, the nature of the sedimentation was observed with the eye alone.

Already one hour later, the starch sediment dropped to the undivided area below the 100 ml mark. The sediment formed a very solid layer in 24 hours and very difficult to shake.

Comparative Example 2

The procedure described in Comparative Example 1 was followed, with the difference that an additional 200 g of urea was dispersed during mixing. During mixing, the urea dissolved, a sedimentation test could not be performed.

30 Comparative Example 3

The procedure was as shown in Comparative Example 1, except that 150 g of anthraquinone were dispersed instead of starch. Already one hour later, the anthraquinone sediment in the sedimentation cylinder dropped to the undivided area below the 100 ml mark. Sediment 7 72433 formed a very solid and difficult to shake layer in 24 hours.

Example 1 The procedure of Comparative Examples 1 to 3 was carried out, except that 200 g of urea, 40 g of starch and 150 g of anthraquinone were dispersed in 500 ml of water with stirring. After 10 hours or 2 hours, respectively, no sedimentation could be detected in the sedimentation cylinder; After 24 hours, another 5 ml of clear medium could be seen on top of the sediment. After 24 hours of sedimentation, no sediment formed, the dispersion remained homogeneous and easily shaken.

15 Comparative Example 4

The procedure was as shown in Comparative Example 2, except that 200 g of potassium chloride was dispersed instead of 200 g of urea. During the stirring, only part of the potassium chloride dissolved. After filling the suspension formed in the saturated KCl solution 20, a very rapidly settling system was formed. After only an hour, the sediment dropped to the undivided area below the 100 ml mark. The sediment formed a very solid and difficult to shake layer in 24 hours.

25

Comparative Example 5

The procedure was as shown in Comparative Example 2, except that monoammonium phosphate was dispersed. During dispersion, some of the monoammonium phosphate was dissolved. The saturated monoammonium phosphate suspension settled rapidly in the sedimentation cylinder, after only one hour the sediment dropped to the undivided area below the 100 ml mark. After 24 hours, the sediment was fluffy but had a very small volume of 35, shaking did not produce any particular problems.

8 72433

Comparative Example 6

The procedure was as shown in Comparative Example 5, except that 150 ml of $ 25 ammonium hydroxide was added to the suspension during suspension.

5 The suspension sedimented more slowly in the 250 ml sedimentation funnel than was observed in Comparative Example 5, but nevertheless the volume of sediment decreased slightly below the 100 ml mark after one hour. The sediment was relatively well shaken after 24 hours.

10

Example 2

The procedure was as in Example 1 or 2, respectively, with the difference that 500 g of urea and 250 g of starch, premixed dry, were dispersed in 500 ml of water. The system thus prepared had a very high viscosity, shaking was hampered by the viscosity. The system did not sediment even after 24 hours.

20 Example 3

Proceed as described in Example 1, except that 1870 g of urea, 40 g of starch, 100 g of monoammonium phosphate, 25,900 g of 255 g of urea were dispersed in 650 ml of water in a nitrogen-phosphorus-potassium ratio of 1: 0.5: 0.5. % ammonium hydroxide and 880 g potassium chloride. The dispersion thus formed, with an active substance content of 40%, did not sediment within 1 or 2 hours, respectively, after 24 hours 7.5 ml of a clear medium formed on the surface of the suspension. No sediment 30 was formed. The suspension could be easily shaken.

Example 4

Proceed as described in Example 3, except that 900 g of ammonium hydroxide, 720 g of urea, 1000 g of monoammonium phosphate and 40 g of ammonium hydroxide were dispersed in 30 ml of water in a nitrogen-phosphorus-potassium ratio of 1: 1: 0 35. g of starch. The dispersion thus formed, with an active ingredient content of $ 40, did not sediment in a 250 ml sedimentation cylinder within 15 hours or 2 hours, respectively. After 24 hours, 5 ml of a clear medium formed on the surface of the suspension. Homogenization was not required. No sediment formed. The suspension could be easily shaken.

10 Example 5

Proceed as described in Example 3, except that 900 g of ammonium hydroxide, 1000 g of monoammonium phosphate, 720 g of urea, 880 g of potassium chloride and 40 g of ammonium hydroxide were dispersed in 710 ml of water in a nitrogen-phosphorus-potassium ratio of 1: 1: 1. g of starch. The dispersion thus prepared with an active ingredient content of $ 40 did not sediment in a 250 ml sedimentation cylinder within 1 or 2 hours, respectively. After 24 hours, 10 ml of clear medium formed on the surface of the suspension. No sediment formed. The suspension could be easily shaken.

Example 6

The procedure was as described in Example 3, except that 720 g of urea, 1000 g of monoammonium phosphate, 900 g of ammonium hydroxide, i860 g of potassium chloride and 50 g of urea were dispersed in 920 ml of water in a nitrogen-phosphorus-potassium ratio of 1: 1: 2. g of starch. The dispersion did not sediment within 1 or 2 hours, respectively. After 24 hours, 2.5 ml of a clear medium formed on the surface of the suspension. No sediment formed. The suspension could be easily shaken.

Example 7 35 The procedure was as described in Example 3, except that 300 g of ammonium hydroxide, 280 g of urea, 1000 g of monoammonium phosphate were dispersed in 1100 ml of water in a nitrogen-phosphorus-potassium ratio of 1: 2: 3 to 10 72433. , 0 g of starch-containing cereal flour and 1350 g of potassium chloride. The dispersion did not sediment within 5 l or 2 h, respectively. After 2 hours, 12.5 ml of a clear medium formed on the surface of the suspension. No sediment formed. The suspension could be easily shaken.

Example 8 125 g of urea, 1250 g of monoammonium phosphate, 375 g of ammonium hydroxide, 20 g of starch and 2656 g of potassium chloride were dispersed in 1750 ml of water. The dispersion thus obtained, containing 40% of active ingredient, did not sediment in a 250 ml sedimentation cylinder within 1 or 2 hours, respectively. After 2H, 15 ml of clear medium formed on the surface of the suspension. No sediment formed. The suspension could be easily shaken.

Claims (3)

72433 A process for the preparation of aqueous, non-sedimentable dispersions, such as artificial fertilizer suspensions, by dispersing solid particles in water, characterized in that before preparing the dispersion in water or an aqueous medium or dispersion containing solid particles, a mass of 1-50 is preferably added relative to water. 2-10 mass JS of starch, 10 and at least equal to the amount of starch, up to fifty times, preferably 2 to 10 times the amount of urea. Process according to Claim 1, characterized in that the starch is used in uninsulated form, in the form of natural substances containing starch. Process according to Claim 1 or 2, characterized in that both starch and urea are used in the form of a dry mixture.