Method of producing ammophos

FIELD: chemical industry.

SUBSTANCE: method comprises neutralizing phosphate acid by ammonium, granulating, drying the product in the drum granulator-dryer, classifying granules, and cooling the finished product in a fluidized bed, with supplying ammonium for neutralizing in amount that exceeds the value required for the product by 0.2-0.5% (on conversion to nitrogen). The finished product is cooled under the rarefication of 300-600 mm Hg, and the fluidized bed is blown by the atmospheric air produced in the rarefication.

EFFECT: enhanced efficiency.

3 ex

 

The invention relates to a method for producing mineral fertilizers, such as ammonium sulphate, which is widely used in agriculture.

A known method for the production of ammophos, including the neutralization of phosphoric acid with ammonia, and subsequent Donatello obtained slurry, granulating, drying, classification of the product and subsequent cooling of the commodity fraction of granules. In this way we obtain a phosphate. The neutralization of phosphoric acid with ammonia first lead to a molar ratio (mo) NH3:H3PO4=0,7 and daemonization conduct liquid ammonia in ammoniator-granulator (AG) to mo NH3:H3RHO4=1,0-1,05. The total amount of ammonia supplied to both stage corresponds to the content of the product is 12% nitrogen.

Drying of the product are in straight-through dryer drum. The dried granules disperse on vibrating screens. Fine fraction as retur return in ammoniator-granulator. A large fraction is sent for crushing. The product fraction is partially used as rature, and the rest corresponding to the time of performance, refer to cooling in the refrigerator, where it is cooled by atmospheric air to a temperature of ≤60°C.( Way, ASI. Phosphate fertilizers in Russia. M: Margus., 1995, s-228.)

However, the scheme is and using AG, but gives a great performance, but has a high returnest.

Closest to the proposed is another well-known method of obtaining map, which allows you to reduce returnest process. The process is carried out as follows. Phosphoric acid concentration 36-37% P2O5neutralized by ammonia in one step, then the resulting slurry is served in a drum granulator-dryer (BGS) and spray compressed air on the veil reture. In the apparatus BGS enter the coolant. The product of the BGS serves on the classification and commodity fraction of the cooling apparatus with fluidized bed at atmospheric pressure. (Technology of phosphate and compound fertilizers. Edited Sudionika and Ads, M.: Chemistry, 1987, s-192). This method can significantly reduce returnest process (from 4-5 up to 1-1,5), but with reduced performance from 35 to 23 t/h for BGS with a diameter of 4 m, because this is a less concentrated acid.

The use of more concentrated acid in the circuit with the apparatus BGS leads to the formation of dense slurries beyond the granulation.

We have been tasked to develop a method of obtaining map, which would allow low returnest performance is not less than the method using the apparatus of AG.

The task is solved in the proposed method of obtaining map including neutralization of concentrated phosphoric acid with ammonia, granulation and drying of the product in the drum granulator-dryer, a classification of the granules and cooling of the finished product in the fluidized bed. By this method using concentrated phosphoric acid, to neutralize serves ammonia in an amount of 0.2-0.5% abs. (in terms of nitrogen) greater with respect to the desired product and the cooling of the granules of the finished product are under a vacuum of 300-600 mm of water. Art. and blown fluidized bed atmospheric air received through this depression.

In the development of any mode of production is the main task of improving its performance. In this case, when using BGS, which can significantly reduce returnest, productivity can be raised by increasing the concentration used wet-process phosphoric acid, but the resulting thick slurry, which is poorly granulated and transported. This can be avoided by increasing the amount of injected ammonia, but such content in the product is not required. The excess of ammonia, therefore, should be deleted, but remain in the process, without increasing its content in the exhaust gases.

Removal of excess ammonia from the granules is achieved by the fact that in predlojeno fashion cooling of the granules of the finished product in the fluidized bed are under the pressure of 300-600 mm of water. Art. Vacuum allows to separate the part of the ammonia, the excess of which is contained in supplied to the cooling of the product.

Desorption of ammonia takes place with absorption of heat, which, along with the exception of heating during the compression of the incoming fluid layer of air provides increased heat removal and, consequently, performance in comparison with known methods. Released at the stage of cooling the ammonia is returned to the process. The reduction of vacuum in the fluidized bed below 300 mm waters. Art. does not provide uniform distribution of the coolant over the layer of product that dramatically reduces the cooling efficiency, and therefore productivity. The increase in the vacuum in the fluidized bed more than 600 mm of water. Art. creates significant takeaway commodity fraction of the product from the apparatus, which complicates its operation due to the necessity of cleaning the waste coolant. As for the excess input stage neutralization with ammonia, the following should be noted: the specified limits (0.2-0.5% abs. in terms of nitrogen from the desired in the finished product) is sufficient to improve granulometry. Reducing it below 0.2% abs. virtually no effect on the process, and increase it by more than 0.5% abs. impractical, since the ammonia in such quantities at the stage of cooling is not desorbed.

The use of the proposed method will allow to process for the BGS concentrated phosphoric acid and thus increase the efficiency of the process in 1.5-2 times compared with the method of the prototype. Furthermore, the method allows the use of atmospheric air without compression, which increases the driving power and cooling efficiency.

The method is illustrated by the following examples.

Example 1. Wet-process phosphoric acid in a concentration of 45% P2O5in the amount of 48 t/h serves for irrigation scrubber, through which the exhaust gases from the drum granulator-dryer and refrigerator fluidized bed. Acid absorbs 0.28 t/h of ammonia released from the dry granulated product in the cooling process. Partially ammonitina acid enters the tubular reactor, which served also 4,89 t/h of ammonia. The resulting slurry, containing (in terms of dry product) 12,20% nitrogen (excess of 0.2% abs.), granulated and dried in the apparatus BGS (with a diameter of 4 m and a length of 22 m). The obtained granules are classified by size and product fraction 2-5 mm at a temperature of 85°With directed to the office (area of 9 m2) fluidized bed, where the tail fan, a vacuum of 300 mm Vogt Sucked into the machine air in quantity is as 50000 nm 3per hour at a temperature of 22°With leads in a fluidized state and cools the granules. At the same time from them is 0.28 t/h of ammonia supplied with exhaust air from the scrubber. From the refrigerator unload 35 t/h of ammonium sulphate at a temperature of 45°With a nitrogen content of 12%.

Example 2. Wet-process phosphoric acid in a concentration of 45% R2About5in the amount of 48 t/h serves for irrigation scrubber, through which the exhaust gases from the drum granulator-dryer and refrigerator fluidized bed. Acid absorbs 0,20 t/h of ammonia released from the dry granulated product in the cooling process. Partially ammonitina acid enters the tubular reactor, which is equal to 4.97 t/h of ammonia. The resulting slurry, containing (in terms of dry product) to 12.35% nitrogen (excess of 0.35% abs.), granulated and dried in the apparatus BGS (with a diameter of 4 m and a length of 22 m). The obtained granules are classified by size and product fraction 2-5 mm at a temperature of 85°With directed to the office (area of 9 m2) fluidized bed, where the tail fan, a vacuum of 450 mm Vogt Sucked into the apparatus of the atmospheric air in the amount of 50000 nm3per hour at a temperature of 22°With leads in a fluidized state and cools the granules. At the same time of n is x is allocated to 0.20 tons/hour of ammonia, coming together with the exhaust air from the scrubber. From the refrigerator unload 35 t/h of ammonium sulphate at a temperature of 45°With a nitrogen content of 12%.

Example 3. Wet-process phosphoric acid in a concentration of 45% P2About5in the amount of 48 t/h serves for irrigation scrubber, through which the exhaust gases from the drum granulator-dryer and refrigerator fluidized bed. Acid absorbs 0,11 t/h of ammonia released from the dry granulated product in the cooling process. Partially ammonitina acid enters the tubular reactor, which served also of 5.06 t/h of ammonia. The resulting slurry, containing (in terms of dry product) 12,50% nitrogen (excess of 0.5% abs.), granulated and dried in the apparatus BGS (with a diameter of 4 m and a length of 22 m). The obtained granules are classified by size and product fraction 2-5 mm at a temperature of 85°With directed to the office (area of 9 m2) fluidized bed, where the tail fan, a vacuum of 600 mm Vogt Sucked into the apparatus of the atmospheric air in the amount of 50000 nm3per hour at a temperature of 22°With leads in a fluidized state and cools the granules. At the same time from them is of 0.11 tons/hour of ammonia supplied with exhaust air from the scrubber. From the refrigerator unload 35 t/h of ammophos in tempera is ur 45° With a nitrogen content of 12%.

A method of obtaining map, including the neutralization of phosphoric acid with ammonia, granulation and drying of the product in the drum granulator - dryer, a classification of the granules and cooling of the finished product in the fluidized bed, characterized in that it serves to neutralize the ammonia in the amount of 0.2-0.5 abs.% (in terms of nitrogen) greater with respect to the desired product and the cooling of the granules of the finished product are under a vacuum of 300-600 mm of water. Art. and blown fluidized bed atmospheric air received through this depression.



 

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FIELD: medicine and microbiology; agriculture and food industry; methods of production of monopotassium phosphate.

SUBSTANCE: the invention is pertaining to production of monopotassium phosphate used as fertilizers, food additives, and also in medicine and microbiology. The method provides for neutralization of phosphoric acid by potassium carbonate up to pH not above 4.5 at the heightened temperature, separation of the produced admixture by filtration with the subsequent crystallization and separation of the finished product at cooling. Potassium carbonate take in the form of a water solution with the concentration necessary for production in the neutralized mixture of 23-30 % monopotassium phosphate. The neutralization process is conducted at the temperature of 70-78°C, and the mother liquor after separation of the finished product at the stage of a crystallization return into the process on the stage of dissolution of potassium carbonate. Reaction of the neutralization conduct up to pH = 3.8-4.5. The technical result is an increase of output of the finished product up to 95-97 % and creation of the wasteless production due to utilization of a mother liquor in the process.

EFFECT: the invention ensures increased output of the finished product up to 95-97 %, creation of the wasteless production due to utilization of a mother liquor in the process.

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SUBSTANCE: method of manufacturing complex granulated mineral fertilizer consists in mixing ammonium nitrate and monoammonium phosphate-containing phosphate additive. The latter is granulated mineral double fertilizer simultaneously containing ammonium nitrate, monoammonium phosphate, and calcium phosphates at total content of digestible phosphorus 13÷21% (calculated as P2O5). Additive is introduced by way of melting it followed by admixing resulting melt to molten ammonium nitrate. Phosphate additive utilizes nitroammophosphate at weight ratio N:P2O5 equal to 23:21 or 26:13 and phosphate additive melt is preliminarily completely or partly separated from infusible solid phase, after which phosphate additive is introduced in amount 2-6% (as P2O5) of the weight of final product. Granulated mineral fertilizer contains ammonium nitrate and monoammonium phosphate with total content of digestible P2O5 within a range of 2÷6%, in which case 0.4÷28.6% of P2O5 is present in the form of dicalcium phosphate.

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FIELD: medicine and microbiology; agriculture and food industry; methods of production of monopotassium phosphate.

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EFFECT: the invention ensures increased output of the finished product up to 95-97 %, creation of the wasteless production due to utilization of a mother liquor in the process.

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FIELD: chemical industry.

SUBSTANCE: method comprises neutralizing phosphate acid by ammonium, granulating, drying the product in the drum granulator-dryer, classifying granules, and cooling the finished product in a fluidized bed, with supplying ammonium for neutralizing in amount that exceeds the value required for the product by 0.2-0.5% (on conversion to nitrogen). The finished product is cooled under the rarefication of 300-600 mm Hg, and the fluidized bed is blown by the atmospheric air produced in the rarefication.

EFFECT: enhanced efficiency.

3 ex

FIELD: agriculture, obtaining fertilizers.

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EFFECT: higher efficiency of application.

10 cl, 8 ex

FIELD: chemical industry, agriculture.

SUBSTANCE: invention relates to method for production of double NP-fertilizer containing 3-7 mass % of P2O5 from concentrated ammonium nitrate solution and extractive phosphoric acid solution. Starting phosphoric acid (52-54 %) is diluted with weak ammonium nitrate solution, diluted solution is additionally treated with ammonium nitrate to produce NH4NO3:P2O5 ratio in ammoniated solution not less than 3:1, wherein ammoniating is carried out simultaneously with auxiliary treatment or thereafter. Ammoniated solution is boiled down to produce residual water content of 5-20 mass % and mixed with concentrated ammonium nitrate solution. Then obtained solution is finally neutralized with ammonia, boiled down and grained. Phosphorous content in ammoniated solution is maintained preferably from 4 to 10 mass % calculated as P2O5, and as ammonium nitrate in auxiliary treatment of diluted solution preferably concentrated ammonium nitrate solution obtained by nitric acid neutralization with ammonia or 40-50 % solution obtained by conversion of calcium nitrate with ammonium carbonate is used.

EFFECT: simplified method for production of complex nitrogen-phosphorous fertilizer.

5 cl, 3 ex

FIELD: fertilizers, chemical technology.

SUBSTANCE: invention relates to a method for preparing granulated ammophos. Method involves neutralization of phosphoric acid with ammonia, granulation of product by pulp raising dust on the recycle particles in the presence of acid agent added in the amount necessary for providing pH value of granulated mixture 3.5-4.8 and simultaneous drying the ready product. Acid neutralizing agent is applied preliminary on the recycle granules surface at temperature 70-90°C wherein the recycle is taken with granules strength 3-8 MPa. As acid agent method involves using phosphoric and/or sulfuric acids. Invention provides increasing yield of commercial fraction 2-5 mm up to 80-90%.

EFFECT: improved preparing method.

2 cl, 1 tbl, 1 ex

FIELD: chemistry, agriculture, fertilizers.

SUBSTANCE: invention relates to method for production of complex fertilizers by decomposition of apatite concentrate with nitric acid by using low-grade phosphate raw materials are used. Claimed method includes decomposition of apatite concentrate with nitric acid, calcium nitrate isolation from nitrophosphate extract, crystallization followed by conversion thereof in ammonium nitrate; neutralization of separated nitrate-phosphate solution with ammonia, vaporization, blending of evaporated pulp with low-grade phosphate raw materials, ammonium nitrate and potassium salt; granulation and drying of finished product. According to this invention low-grade phosphate raw materials are preliminary treated with conversion ammonium nitrate solution at S:L = 1:1-3 to produce in slurry ratio of P2O5digestible:P2O5total = 35-45 %. PH of conversion solution is maintained preferably either 0.3-1.5 or 7.5-9, with the proviso, that when pH is 0.5-1.5 ratio of apatite and low-grade phosphate raw materials calculated as P2O5 is (1.5-3):1; and when pH is 7.5-9 abovementioned ratio is (4.2-5):1.

EFFECT: product of prolonged action, simplified process without losses of product quality.

2 cl, 1 tbl

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