DE1226994B - Process and plant for the production of a salt mixture consisting of sodium magnesium and optionally calcium orthophosphate - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

COIb

German KL: 12 i- 25/26

Number: 1226 994

File number: K 55138 IV a / 12 i

Filing date: January 29, 1965

Opened on: October 20, 1966

Salt mixtures consisting of sodium, magnesium and optionally calcium orthophosphate are Mainly used as an animal feed additive. It is known to mix such salt mixtures together of the phosphates obtained in separate ways. This way of working is inefficient, as it requires a multitude of operations.

It is also known to use finely ground limestone, optionally mixed with ground dolomite with stoichiometric amounts of orthophosphoric acid with a concentration of 84 to 85% to dicalcium phosphate, optionally mixed with magnesium phosphate, avoiding the formation of an aqueous one Implement phase.

If phosphoric acid with a concentration of 75 to 84% H ₃ PO _{4 is} used, so much burnt lime or anhydrous sodium pyrophosphate is added to the limestone or limestone-dolomite mixture that the excess water is bound or evaporated. The starting products are preferably mixed in a pan mixer. In the case of the addition of pyrophosphate, a not inconsiderable increase in cost and possible physiological effects of the polyphosphate must be accepted.

This process has the disadvantage that the sodium pyrophosphate used initially in one separate process is produced and isolated and that the reaction product is then a must be subjected to a longer ripening process.

Surprisingly, it has now been found that a salt mixture, particularly suitable as animal feed and consisting of sodium, magnesium and optionally calcium orthophosphates, can be produced in a simple way in a single operation by using orthophosphoric acid, sodium hydroxide and / or sodium phosphate solutions or mixtures as starting materials of sodium orthophosphate and orthophosphoric acid with magnesium oxide, optionally mixed with calcium oxide, in the amounts required for the formation of secondary phosphates, continuously with constant agitation and mixing, for 10 to 45 minutes. According to the invention, orthophosphoric acid is used with a P ₂ O ₅ concentration of 45 to 60 percent by weight, preferably 50 to 55 percent by weight, and magnesium oxide and optionally calcium oxide with a particle size of less than 0.5 mm, preferably less than 0.1 mm After most of the retained water is released through

Method and plant for the production of a
Sodium, magnesium and optionally
Calcium orthophosphate existing
Salt mixture

Applicant:

Knapsack Aktiengesellschaft, Knapsack near Cologne

Named as inventor:

Dipl.-Chem. Dr. Heinz Harnisch,

Lövenich near Cologne;

Dipl.-Chem. Dr. Joseph Cremer, Hermülheim;

Arnulf Hinz, Knapsack

heat of neutralization is evaporated, the salt mixture obtained is then in a optionally with simultaneous comminution carried out drying process of the remaining adhesive water freed.

The exothermic reaction is carried out so that it takes place at temperatures between 80 and 120 ° C, preferably at about 100 ° C. About 20 to 50% of the phosphoric acid, the sodium hydroxide solution or the sodium phosphate solution introduced into the water.

The salt mixture obtained is freed from the remaining adhesive water, ideally by grinding drying, with the salt mixture with a total water content of about 35 percent by weight as much return material from the mill drying, preferably the resulting oversized grain, admixed that the total water content of the Salt mixture is 25 percent by weight before it is fed to the mill drying. This repatriation of oversized grain in the mixer means none

Reduced capacity of the mill, since the oversized grain would have to be circulated anyway.

Instead of a mixture of MgO and CaO, fired, preferably soft-fired dolomite or a mixture of Mg (OH) ₂ and Ca (OH) ₂ and, instead of a sodium phosphate solution, an orthophosphoric acid can be used as the starting product, which has the desired sodium content in the end product Sodium hydroxide and / or sodium carbonate is partially neutralized.

Such a sodium orthophosphate-orthophosphoric acid mixture should advantageously have a P ₂ O ₅ content of 33 to 43 percent by weight, preferably

609 707/363

3 4

from 36 to 40 percent by weight and one by weight provided all other values

ratio of Na ₂ QcE ₂ O ₅ between 1: 2 and 1: 3, can be kept constant.

preferably 1: 2.5. Except for those mentioned in the table above

It has been shown to be particularly useful that the main components should be used in the described

Starting components, while they are mixed, 5 phosphate mixtures to the following maximum values

to move at the same time over a distance and the impurities are not exceeded:

h d

Output components simultaneously on this mix di A fli

(as SuIfafi 2 0 ° /

to abandon the route, with the abandonment of the liquid f o'l ° /

Starting components preferably at the beginning of this p _e 0 ^? 5 ° / °

Mixing section takes place and the solid starting products 10 ai o'5 ° / °

be abandoned shortly afterwards. '°

_S ^ implementing the encryption inventive 0,004 ° /

Pb;. 0.005 ° / ₀

driving, one system in particular has proven itself '

from a continuous mixer, the amount of fluorine in the salt of less than 0.1 weight

Mixing tools clean themselves automatically, and to keep a 15 percent, must consist of the usually as AusVorrichtung for grinding drying, which is connected to a wet phosphoric acid used in the air classifier, which is set up to remove fluorine. For this purpose, the oversized grain separated in the air classifier can be returned to the starting fluorine content of 4.5 ° / ₀ F in the 31% P ₂ O ₅ mixer. containing crude acid per 100 kg of P ₂ O ₅ about 10 to

To ensure good homogenization of the starting 20 12 kg of NaOH (50%) are added. The fluorine will ensure products, it is advisable to add one or more centrifugal mixers to precipitate and filter them in a known manner as sodium silicofluoride. The so prepurified phosphoric direct introduction of sodium orthophosphate-orthophoric acid is then oxidized to 50% P ₂ O ₅ concentrated phosphoric acid and / or magnesium-calcium with a fluorine content of 0.1 percent by weight. Gefüischenin:; the; Mjsch: to attach it. 25 For further processing of the concentrated

Very good results are obtained when as, phosphoric acid, three different ways of working mixer is a twin shaft mixer is used indicated.

in particular if a part of its 1st pre-cleaned, d. H. defluorinated phosphoric acid

The paddle is set to Gegeütbarensport and weirs are in a stirred tank with simultaneous cooling are installed for damming the moved goods, 30 with the desired sodium content in the end as well as green is used. 'neutralized. Subsequently, with HiUe a dosing

. ^. " . , .._ ..,. _, __. __, pump the acidic sodium phosphate solution obtained

The composition of the inventively manufactured _{dnem Dop} pel _W elle mixer supplied. The salt mixture produced at the same time can be _{varied as follows using a} dolomite belt scale or an MgO. ,., CaO mixture entered into the shaft mixer.

P ₂ O ₅ ... .v 35 to 50% This reduces the conversion of the acidic sodium

Na ₂ O ..: ...,.; .'.... 10 to 20% phosphate solution with the dolomite or MgO-CaO-

MgO. ·. "4 to 22% mixture to a neutral mixture of sodium

CaO 0 to 18% '40 magnesium calcium phosphate initiated. In doing so,

H ₂ O / 800 ^Q C ....... 6 to 23% is initially a thin paste. Through the

P ₂ O ₅ citrate soluble; About 95 to 100% exothermicity of the reaction evaporates

P ₂ O ₅ water soluble 55 to 65% 20 to 50% of that made by the sodium phosphate solution

: · Brought in water. At the same time there will be more

■ The contents of Na ₂ O, MgO, CaO and P ₂ O ₅ differ from 45 free water in the salt formation as water of crystallization depending on the requirements, which are bound during the application, whereby the paste hardens,
of the product are made, being cationic and in order to be necessary for sufficient hardening

anionic components are matched to one another, the residence time in the shaft mixer is about 10 to 45 minus, That the pH of the aqueous slurry th to achieve are part of the paddles on the area finished product between 6 and 8, preferably 50 set transport. At the same time weirs are to at about 7. Built-in accumulation of the product. By the paddle

In this phosphate salt mixture are the sodium of the mixer, the hardening paste becomes an erdals Na ₂ HPO ₄ , with and without crystal water (2 or moist, crumbly to small lumpy product 7H ₂ O), the magnesium as MgHPO ₄ · 3H ₂ O and the divided. The water that evaporates during the reaction occurs as CaHPO ₄ and CaHPO ₄ · 2H ₂ O. 55 is sucked off.

While with dolomite the ratio CaO: MgO has the production of the acidic phosphate solution

is given by nature, e.g. B. 56% CaO: 38% MgO, although the advantage that the P ₂ 0 ₅ -Na ₂ 0 ratio is set before a change in this ratio in the production of a calcium oxide-magnesium processing by analytical monitoring oxide mixture and thus dosing errors are possible. . 60 can be reduced. However, it falls in this case

If you choose the ratio of CaO: MgO, e.g. a relatively moist, difficult-to-process end product 1: 1, the result is roughly the following combined product, if not with the concentration of the Settling of the salt; . pre-cleaned acid has a correspondingly higher concentration

•. ■ '· the centering is set to about 50 to 55% P2O5

P ₂ O _{5 was} 39 to 40.5% ■ 65.

Na ₂ O. "..,. 15.5 to 17.0% For better homogenization of the reaction

MgO '9 to 11% mixture is recommended to use the wave mixer

: CaO .... .;, _ ■ 9 to 11% so-called centrifugal mixer upstream. In

5 6

In this mixer, the solution and solids are combined in a single, lump-free pulp, which is completely homogeneous in the twin-shaft mixer. leaving product in a pendulum roller mill 9 with · This pulp is then dried in the shaft mixer to the hot air supplied through line 10 and ^: further maturing. ground at the same time.

The earth-moist product, which, in addition to the desired 5 The hot air flow from the pendulum roller

about 20% of the total water (800 ⁰ C) still additional grist discharged from the mill is in a classifier 11,

Contains 20 to 25% adhesive water, is separated into end product and coarse grain after passage, whereby the

of the twin-shaft mixer dried. This dry coarse grain is then put into the twin-shaft mixer

tion can either be returned with the help of a rotary tube and / or the pendulum roller mills,

subsequent grinding of the finished product. The end product obtained is passed through a cyclone 12

follow or better in a combined and a filter 13 in storage bunker 14 transferred.

Operation through a grinding drying. . -I ₁

The drying in the rotary kiln has the disadvantage that B e ι s ρ ι e 1 1
Due to the different grain sizes of the moist In continuous operation, a centriproduct that is created in the shaft mixer will result in 15 fugalmixers per minute of about 13 kg (= 780 kg / h) of different lengths of residence time in the rotary kiln. an acidic sodium phosphate solution with 31.3%. The residence time for coarse grains is the lowest P ₂ O ₅ and 12.6% Na ₂ O and around 2.24 kg (= 134.4 kg / h) and the longest for small grains. However, around the coarse CaO-MgO mixture with approximately 45.5% MgO and grain, 45.5% CaO is added to the core despite the shorter residence time. During re-drying, the drying temperature must be 914 kg / h of pulpy reaction product, from which much higher is selected than would be required for drying the small grain after the water has been released in the twin-shaft mixer. As a result, and after the subsequent drying around 620 kg, the small grains not only result in adhesive water, but also in the end product. The same amounts of sodium, as well as part of the desired crystal water, phosphate solution and CaO-MgO mixture can also be expelled, i.e. the drying is inconsistent, 25 by bypassing the centrifugal mixer, and only fed into a homogenous shaft mixer when grinding,
ization.

In the case of mill drying, on the other hand, the drying analysis is:

more even and gentler and therefore the total P ₂ O ₅ 39.6%

pipe preferable. Since in the mill, preferably 30 Na ₂ O 15.9%

a pendulum roller mill, only one product with 8 to 10.3% MgO

15% adhesive water can be processed, CaO 9.8%

from the semolina cycle of the mill approx. 150 to 300 kg H ₂ O 800 ⁰ C 22.0%

Oversized grain per 100 kg moist product as return material to the P ₂ O ₅ citrate-soluble 96%

Shaft mixer are fed so that the total 35 P ₂ O ₅ water-soluble 64%

water content of the crumbly to small lumpy green - pH 7.2

Product at the discharge of the shaft mixer

25%. Example 2

2. The phosphoric acid and the dolomite or that

CaO-MgO mixture are fed to the centrifugal mixer via a metering pump and 40 In continuous operation the centrifugal belt weigher. The mixer per minute about 8 kg (= 480 kg / h) emerging pulp is then in the shaft mixer the purified, concentrated wet phosphoric acid with the desired amount of caustic soda over a further 50% P ₂ O ₅ and about 2.2 kg per minute (= 132 kg / h) dosing pump allocated. This arrangement has the CaO-MgO mixture with about 45.5% MgO and 45.5% advantage that the entire heat of neutralization for 45 CaO is supplied. In addition to the pulp from the centrifugal, evaporation of the adhesive water in the shaft mixer can then be used in the twin-shaft mixer pro, whereas in Example 1, 4.12 kg (= 248 kg / h) sodium hydroxide solution (50%) is allocated to the production of the acidic sodium phosphate solution at minute . From the (860 kg / h) pulp, in turn, the heat is generated during the partial neutralization by cooling after the water has been released during the hardening and has been dissipated beforehand. 50 maturation and after drying 590 kg end product.

3. According to the following flow chart

pre-cleaned and concentrated phosphoric acid analysis:

from container 1 via metering pump 2, sodium hydroxide solution total P ₂ O ₅ 40.6%

from container 3 via dosing pump 4 and dolomite Na ₂ O 15.6%

or a corresponding CaO-MgO mixture of 55 CaO 10.6%

Container 5 via a belt scale 6 directly to a double MgO 11.0%

Shaft mixer 7 supplied. H ₂ O 800 ⁰ C 18.8%

When combined in a twin- _{shaft mixer, P 2} O _{5 is} citrate-soluble 98%

_{With H 3} PO ₄ and dolomite, a homogeneous P ₂ O ₅ is created again, water-soluble 56%

Mash into which the sodium hydroxide solution is then subsequently added. PH 7.3

will wear. Again with this arrangement

the total heat of neutralization for evaporation Example 3

of the retained water exploited.

The amount of water evaporating during the reaction In continuous operation, all three compo-

are discharged via a vapor vent 8. 65 components, pre-purified, concentrated phosphoric acid,

The earth-moist product is dried in dolomite and caustic soda, preferably in the flat

then continue as described under procedure 1 in the sequence of the twin-shaft mixer

became. allocated, namely around 8 kg per minute (= 480 kg / h)

Claims (4)

7 8 phosphoric acid with 50% P2Os> approx. 2.1 kg milled return material from the mill drying is mixed in, burnt dolomite with 55% CaO and that the total water content of the salt mixture is 38.37 o MgO (= 127 kg / h) and 4, 12 kg NaOH. 25 percent by weight before it is fed to the grinding (= 248 kg / h) sodium hydroxide solution (50%) · drying. From the 855 kg / h pulp there are about 580 kg of final product. characterized in that fired, preferably soft-fired dolomite Analysis: is used as the starting product. 16 3 ° / ^ 'Method according to one of Claims 1 to 5,' δ'ΐ ° / ° 10, characterized in that the starting product used is ^ '2 0 / orthophosphoric acid, the one in the HO 8000C 2o'50 / ° end product Desired sodium content corresponds to PO citrate soluble 99> 0 / speaking, is partially neutralized with sodium hydroxide solution and / or sodium P2O5 water inqiidi / ςι o / ° carbonate. _jj η Q is ι · The method according to claim 6, characterized in that a sodium orthophosphate-orthophosphoric acid mixture with a P2O5 content claims from 33 to 43 percent by weight, preferably from 36 to 40 percent by weight, and a weight percent 1. A method for producing an animal ratio of Na ₂ OiP ₂ O ₅ between 1: 2 and 1: 3, suitable for animal feed and from sodium, Magne, preferably 1: 2.5, is used. sium and optionally calcium orthophosphates 8. The method according to any one of claims 1 to 7; existing salt mixture, characterized in that the starting com-2; Eich η et that orthophosphoric acid, naphtha, while they are mixed, tron hydroxide and / or sodium phosphate solutions or are moved over a stretch at the same time.
Mixtures of sodium orthophosphate and orthophosphate 9. The method according to claim 8, characterized in that the starting components are also mixed with calcium oxide in the amounts necessary for the formation of secondary phosphates the liquid starting is continuously mixed with constant mixing for 30 components, preferably at the beginning of this mixing 10 to 45 minutes, with the ortho- "stretch taking place and the solid starting products, phosphoric acid with a concentration of P ₂ O ₅ shortly afterwards,
from 45 to 60 percent by weight, preferably from 10. Plant for carrying out the process 50 to 55 percent by weight, as well as the magnesium according to one of claims 1 to 9, consisting of and optionally the calcium oxide with a continuous mixer whose mixed grain size is below 0.5 mm, preferably beneath tools that clean themselves automatically, and one 0.1 mm, can be used, and then the device for grinding drying, the connected salt mixture obtained, possibly with an air sifter that is set up, timely crushing , is dried. that the oversized grain separated in the air separator in 2. The method according to claim 1, characterized in that the mixer can be recirculated 40, with the fact that the reaction at mixer temperatures is a twin-shaft mixer at which between 80 and 120 ^° C., preferably at about some of the paddles, optionally on counter -100 ⁰ C, is carried out. transport is set, and weirs to accumulate 3. The method according to claim 1 or 2, characterized in that the moved goods are installed,
characterized in that the salt mixture obtained 45 is subjected to grinding drying. 4. The method according to claim 3, characterized marked ^Contemplated publications:
indicates that the salt mixture with a total of German Patent No. 563 234;
water content of about 35 percent by weight as much British Patent No. 519,836. 1 sheet of drawings 609 707/363 10.66 © Bundesdruckerei Berlin