DE2235743C3 - Process for the production of pure trisodium monohydrogen diphosphate - Google Patents

Description

known that the formation of trisodium mono-

Hydrogen diphosphate is not necessary, a mixture 35 ner advised that this can be achieved by spraying

trisodium made from disodium dihydrogen and tetrasodium diphos with water and steaming

phat dissolve in water, but that it is enough monohydrogen diphosphate because of its better

to apply so much water to this mixture that handling should still be dried. in the

hydrate formation can occur. The course of this post-drying process, the

position can be done in such a way that the actual conversion reaction is followed by 40,

Water in a finely atomized state on the powder - that which is introduced in the course of the reaction

sprayed mixture. This can e.g. B. in a rotating water of hydration preferably up to about 1 to 2 mol

drum or done in a ball mill. White water per mole of trisodium monohydrogen diphosphate

terhin is dried away again in German patent specification 974 304. It has been shown that tri-

indicated that by treating the 45 sodium monohydrogen diphosphate, which is an annealing

Have a powder mixture in the fluidized bed with a water loss between 10 and 14 ⁰ O, especially good

steam trisodium monohydrogen diphosphate must be handled.

Ien can. The x-ray shows the pro-fine grinding and post-drying are two

ducts that the lines of the starting mixture reduce factors that make the process economically viable

have waned and heavily burden one for trisodium monohydro 50. But it has not been tried

gene diphosphate characteristic X-ray spectrum is absent, trisodium monohydrogen diphosphate, which

originated. the requirements of the colorimetric test

It has now been shown that the is clear according to FIG

see patent specification 974 304 manufactured trisodium from not specially re-ground starting

monohydrogen diphosphates still produce certain proportions of the 55 materials.

Containing starting materials, that is, the conversion is not complete. According to German Patent 1,941,291, these small proportions make it known that trisodium monohydrogen cannot be determined on a debeyeogram. According to diphosphate, if you have solutions or a new colorimetric detection method suspensions of equimolar mixtures of dilutes but also very low alkaline proportions 60 sodium dihydrogen diphosphate and tetrasodium diine in a phosphate mixture, so that it brings phosphate to a calcining roller and regulates the smallest proportions of unconverted Action conditions are chosen so that no post-Tetranatfiumdiphosphat determine. According to this drying cycle, a trisodium monohydroin of the German Auslegeschrift 1 938 194 detailed gene diphosphate with a maximum of 2 moles of water of hydration per described detection method can be obtained in a product with 1 mole of water of hydration in a product with 1 mole of water of hydration, alkaline trisodium monohydrogen diphosphate prepared according to 65 moles of trisodium monohydrogen diphosphate, preferably according to German patent 794 304 ,
components are proven. The major disadvantage of this method is

3 4

but in the fact that one from economic over- Of particular advantage is that that on

is forced to use a relatively high concentration of the introduced starting mixture in the heated

triert, z. B. 20 to 70% solutions and suspensions temperature range not applied water

sjonen to work. Such solutions and suspensions must be injected in a finely atomized form

Sions can, however, only be produced by heating. It is enough to let it run in slowly or

and kept stable. The result is that when adding portions in the course of only

the operational downtime of a few minutes.

solutions and suspensions before application to the In order to ensure that trisodium mono-

Calcining roller pyro- to orthophosphate degraded to achieve hydrogen diphosphate, is it useful? «A

will. Pro io end product produced under operating conditions with about 1 to 2 moles of water per

Products contain up to 20% orthophosphate. Moles of trisodium monohydrogen diphosphate

The common disadvantage of the German len. According to the method described, patent 1941291 and the German interpretation are easily made possible by the fact that the method described with the writing 1938 194 consists of set water in motion -Products with a relatively low bulk density range between 80 and 250 ⁰ C a somewhat can be obtained. Both methods are subject to longer reaction times. It is not possible because of this. To obtain products that have a possible bulk density of more than 600 g / l in one process step. Such hydrate level of trisodium monohydrogen diphosphate products are characterized by a high ao targeted production, with the desired final dissolution rate, but on the other hand always require the requirements of the colorimetric a relatively large-volume packaging space and test

tend to generate dust. In practice, the procedure described with the Verden also trisodium monohydrogen diphosphate using a relatively coarse starting material, the wishes that have a higher bulk weight. The 25 simple introduction of the necessary water requirements in terms of bulk weight and the saving of separate aftersales between 400 and 1100 g / l, but preferably intermediate drying means compared to the known gossip 500 and 800 g / l. drive a significant technical advance.

A process for the production of Hydration of a phosphate mixture of disodium bulk density of the tridihydrogen diphosphate obtained in the final state and tetranate diphosphate specifically influence sodium monohydrogen diphosphate Found at least 2 moles of water to be able to do this.

is characterized by the fact that it is z. B. impossible, easy trisodium mono-

a trisodium monohydrogen diphosphate with a 35 hydrogen diphosphate by grinding harder

Bulk weight from 450 to 1100 g / l making phosphate. When grinding according to the German

mixture to a temperature between 80 and Auslegeschrift 1 938 194 or the German patent

Heated to 250 ° C., with intensive mixing with washing machine 1 941 291 produced projects that a

water and have a bulk density of around 500 to 600 g / l with constant movement,

Holds at the specified temperature until the hydrate 40 is kept on the Alpine mill with products

water content between 1 and 2 moles per mole of tri. bulk weights below 400 g / l, on the Pallmann

sodium monohydrogen diphosphate, whereby at Mühle bulk weights of a maximum of 450 g / l and on

Increase the amount of water added, the debris of the ball mill bulk weights of a maximum of 600 g / l.

weight increases. Bulky weights that are too light, however,

The new process makes it possible to produce pure 45 rem in addition to the disadvantage of the high packaging

Trisodium monohydrogen diphosphate, which has no alkali volume, has the serious disadvantage of being light

Has lischen components, in a single dusting with it.

speed level in a short time. According to the method described here, it is not necessary to proceed from a finely ground bulk weight depending on an added weight that does not remain in the starting material as in the known methods. In the German Auslegeschrift 1 938 194 water volume set between 450 and 1100 g / l it is expressly pointed out that the excess. This is all the more astonishing because while the mixture is being converted into a pure trisodium mono-reaction process with a relatively high rate of hydrogen diphosphate, it is essential that stirring or mixing be carried out so that the constituents of the mixture can be used in very fine-grained form to form granulated materials begins. It is not given by way of example. The higher the added water, i.e. 85% of the starting mixture, the higher the bulk density of the DIN 100 and 97% of the standard sieve DIN 70 of the end product. If little water is added, if the required reaction time results in an end product with a low bulk density,
economically justifiable limits are kept 60 The method described also enables the should. In contrast, it enables the production of pure trisodium monohydrogen level process with a starting mixture to diphosphate, which works in the colorimetric test, of which 50% DIN 100 and 70% DIN 70 is sufficient if the starting material is disodium. Already after a reaction time of about 10 minutes of hydrogen diphosphate and tetrasodium dihydrogen, a trisodium monohydrophosphate can be incorporated into mixtures that contain gene diphosphate, in which, for example, ascorbic acid and glucose decolorimetric test do not contain any alkaline constituents. In these cases, too, it is possible for end parts to be detected more. manufacture products that contain pure trisodium mono-

contain hydrogen diphosphates and their pH does not exceed 7.3 in X%,

Carrying out the method according to the invention can be done in various apparatus systems. There are z. B, rotating drums of different designs, fluidized bed apparatus, standing drums or cylindrical vessels, in with stirring or mixing tools rotating.

example 1

A mixture of 250 g of tetrasodium diphosphate (passage DIN 70 = 70, DIN 100 = 50%) and 210 g of disodium dihydrogen diphosphate (passage DIN 70 = 80 ° / β, DIN 100 = 50%) was mixed in a double Z kneader preheated to 120 ° C ¹ Vo) »5 and 180 g of water are added in portions over the course of 3 minutes.

After a reaction time of 15 minutes, no more alkaline constituents could be detected in the mixture will. »°

reaction time
(Min.) Colorimetric
test Loss on ignition
(Weight
percent) Sohütt-
weight
(g / 1) 15th
30th
45 negative
negative
negative 21.2
11.2
9.8 940
920
870

reaction time
(Min.) Colorimetric
test Loss on ignition
(Weight
percent) Schütl
weight
(g / l) 10
15th
20th
30th negative
negative
negative
negative 18.2
15.5
10.5
8.8 745
745
670
625

Example 3

50 kg of a mixture according to Example 1 preheated to 12O ⁰ C in EFCEM Turbuient-speed mixer were added, the MischerfuHung at 70 '/ q lay of the available volume. While mixing at the same time, 12.51 local water was poured in over the course of 3 minutes.

Example 2

In a double-Z kneader preheated to 120 ° C 120 g of local water were added to 460 g of a mixture according to Example 1. Already after No more alkaline constituents could be detected in the mixture for a reaction time of 10 minutes will.

reaction time
(Min.) Colorimetric
test Loss on ignition
(Weight
percent) Bulk
blows
(g1) 30th
40
50 negative
negative
negative 18.9
15.7
13.9 940
910
892

Example 4

According to Example 3, -.- *
Added over a period of 3 minutes.

10 I water in

Response line
(Min.) Colorimetric
test Loss on ignition
(Weight
percent) rubble
weight
(g'D 30th
40
50 negative
negative
negative 13.9
12.9
11.2 700
680
620

Example 5

In a fluidized bed 3 m long and 20 cm wide, 200 kg of a mixture per hour

enforced, which contains 26.6 parts of tetrasodium diphosphate, 22.2 parts of disodium dihydrogen diphosphate, 10 parts of ascorbic acid and 20 parts of glucose. In addition , 15.9 parts of tetrasodium diphosphate were added to neutralize the ascorbic acid. The fluidizing air temperature was 125 ° C.

No more alkaline constituents could be detected in the granulated material obtained, the pH value (1%) of the product was 7.3, the bulk density was 520 g / l.

Claims (2)

ι 2 p _ofBntoncnri . In the German Auslegeschrift 1 938194 a raient requirements. Procedure described through which a complete Process for the production of pure tri-implementation of the equimolar mixture of di- sodium monohydrogen diphosphate by hydra sodium dihydrogen and tetrasodium diphosphate tion of a phosphate mixture of disodium 5 trisodium monohydrogen diphosphate can be achieved dihydrogendipbosphat and tetrasodium diphos- can by laan the mixture with at least 1 mol phat with at least 2 moles of water, thereby spraying water and at the same time or afterwards g e k e η η ζ e ί c h η e t that one treats with steam for production. In one according to this of a trisodium monohydrogen diphosphate produced with the process can with the a bulk density of 450 to 1100 g / l the ι ο colorimetric test no alkaline components Phosphate mixture can be detected at a temperature between more. 80 and 250 ° C heated, with intensive mi A successful work according to this process see mixed with water and so long under standing requires the use of mixture components diger movement at the specified temperature in a very fine-grained form. According to the German holds until the water of hydration content is between 1 and 15 Auslegeschrift 1938194 should be 85% of the initial 2 mol per mole of trisodium monohydrogen diphos mixture the standard sieve DIN 100 and 97% phat, with increasing the added standard sieve DIN 70 happen. When working with The amount of water the bulk density increases. coarser starting materials will be the steaming time of the product that was previously sprayed with water, before a trisodium monohydrogen diphosphate is obtained in which no more alkaline components can be detected. This also applies to dinn, if according to Trisodium monohydrogen diphosphate arises from the German patent specification 974 304 with a common orthocalcinate leading to a common orthocalcinate directly from the German patent specification 974 304, whereby intimate mixtures are used as a mixture,
Crystallized from anhydrous salt and various hydrate urns in one step by the German Auslegeschrift 1938194. But you can also get a described end product, so the equimolar mixture of disodium dihydrogen and starting materials must be ground very finely. Tetrasodium diphosphate dissolve and the hydrates 30 This grinding takes time and money, ie. of the trisodium monohydrogen diphosphate by the economic efficiency of the overall process will gain crystallization, significantly from the necessary grinding costs. According to German patent specification 974 304, it is influential.