CS254028B1 - Granulated multi-component fertilizer and method of production - Google Patents

Abstract

The solution relates to granulated NPK fertilizers containing a part of the phosphorus component in the form of phosphorite, preferably treated by grinding. Other components of the fertilizers are ammonium phosphates, ammonium polyphosphates, ammonium sulfate and potassium chloride or potassium sulfate, while the fertilizers may also contain ammonium nitrate, natural zeolite and a binder. The fertilizers are produced by a melt granulation method based on the neutralization of mineral acids with ammonia. The product of the neutralization reaction is continuously granulated with solid raw materials and returnable material, while these are homogenized with phosphorite, preferably treated by grinding, in the granulation process. For more difficult granulable fertilizer formulations, a binder is also added to the granulation process.

Description

BACKGROUND OF THE INVENTION The present invention relates to granular, phosphorous-containing, multi-component fertilizers and a process for their production.

Despite the well-known, especially economic benefits - the low cost, the application of ground phosphite worldwide represents only about 5% of the used phosphate fertilizers. The main disadvantages of the use of ground phosphites are the uncertainty of their agronomic value and, in particular, the problematic handling and application of the finely ground powdered material. According to data from Fertilizer Manual, Development and Transfer of Technology, Series no. 13, UNIDO, New York 1980, it is necessary to provide a fine grinding of phosphorous such that 90 wt. the particles were smaller than 0.147 mm, or preferably a higher efficiency of 80% w / w. particles smaller than 0.043 mm. It is generally accepted that the use of such classical ground phosphites is, from an agronomic point of view, only effective on acidic pH á 6, with the long-term effect of their use being more favorable than their short-term effect. Granulation of the ground phosphorites resolved the problems associated with the handling and application of the fine dusty material, but the treated product had little agronomic efficacy, since the granulation significantly reduced the ground phosphorite-to-ground contact surface, transforming the ground phosphite into plant-accessible forms of P2O5. In addition to reducing agronomic efficiency, a further disadvantage of granular ground phosphites is their difficult granulation without the use of a suitable binder, which however complicates the manufacturing process and makes it more expensive. Podfa Μ. P. Thúringa - paper from AGRICHEM, VI. congress "Chemistry in Agriculture", June 1984, Bratislava, it is advantageous to carry out the granulation of phosphorites in a plant consisting of two successive parts - a pre-granulator and a granulation granulator. The advantage of this process is that the granules are obtained without any binders except water and steam. The disadvantage is that the granulation process must be carried out in two stages. Also, the application of phosphite and activated phosphite suspensions did not bring the expected progress in the development of the use of ground phosphite, mainly due to some disadvantages related to agronomic efficiency, storage and application. These drawbacks of the use of ground phosphites are overcome by the invention.

The present invention provides granular compound fertilizers containing 4 to 19 wt. % of total nitrogen, 13 to 45 wt. % of total P2O5, wherein 35 to 82 wt. % of the total P2O5 content is in the form of ammonium phosphates. The fertilizers further comprise 10 to 28 wt. % K2O in the form of potassium chloride and / or potassium sulphate and also substances modifying their physicochemical and mechanical properties. Fertilizers are characterized in that they contain, from a total P2O5 content, 5 to 48 wt. % P2O5 in the form of phosphites and 0.3 to 45 wt. % P2O5 in the form of condensed ammonium phosphates. Fertilizers further contain 7 to 35 wt. % ammonium sulfate.

The invention furthermore relates to a process for the production of granular compound fertilizers of the above-mentioned general formula, which is based on the continuously guided neutrallization of trihydrogenphosphoric acid or a mixture thereof with sulfuric acid, ammonia and / or ammonium nitrate ammonate. The product of the neutralization reaction is continuously granulated with solid feedstocks and a return material. The process is characterized in that the incorporation of phosphorus into the fertilizer granules occurs after contact of the melt part of the neutralization reaction reaction product, which has the character of a melt-steam-gas mixture, with the phosphite particles. Contact is effected by spraying the neutralization reaction product onto the surface of the granulation mass in the granulation apparatus. The degree of conversion of the monophosphate component into the linearly condensed ammonium phosphates in the melt is 0.3 to 75% and its temperature, depending on the composition and the neutralization process, is 145 to 395 ° C and the weight ratio of P2O5 in the melt and phosphite is 0.05 to 0.092 .

It is advantageous to treat the phosphorite by grinding to a particle size such that min. 80 wt. the particles were smaller than 0.20 mm. In this way, its consistency is guaranteed from a granulometric point of view and a better granulation efficiency of the process is achieved as well as its better utilization by plants, for some fertilizer compositions preferably a binder in the form of a sulphite liquor or thickened sulphite stillage is added. The raw granulate leaving the granulation equipment is further processed in the production of granular fertilizers by generally used drying, sorting, cooling and surface treatment processes.

Said granular fertilizers, by their granulometric composition and their physicochemical properties, ensure good handling and uniform application to soil. An essential advantage of the invention is the possibility of use in fertilizers incorporated with phosphorites also on soils with a pH higher than 6. After dissolution of the granules the fertilizer in the acid reacts, in particular the anions of CO4 ² ', HzPCU' and Cl ^- phosphorus, forming forms of P2O5 with good usable plants. By their composition and phosphorus content in the form of phosphites *, ammonium phosphates * and ammonium polyphosphates, the granular multicomponent fertilizers of the present invention provide high short and long-term agronomic efficacy of the phosphorous component for a wide range of crops under various climatic and soil conditions. The process of producing granular multi-component fertilizers according to the invention makes it possible to produce a wide range of NPKs of granular fertilizers with a barbecue form and a ratio of basic plant nutrients, thus ensuring their suitability for use in scientifically controlled nutrition of agricultural crops. The effect of the addition of ground phosphites on the granulation efficiency of the production process is at a level comparable to that of fine KCl.

The granulated multi-component fertilizers and the process for producing them illustrate, but do not limit the invention in any way.

Example 1

The following raw materials were fed continuously into the model pipe reactor:

42.5 kg / h of extraction H3PO4 containing 52.2 wt. % P2O5,

8.0 kg / 92.3% H2SO4

8.5 kg / gaseous concentrated ammonia.

The vapor-liquid mixture produced in the reactor was sprayed into a model drum-type granulator into which the following solid raw materials were simultaneously fed:

16.5 kg / h of ground phosphorus containing

33.4 wt. % P2O5, a particle size distribution of 80% of particles less than 0,20 mm,

34,0 kg / h of potassium salt - KCl containing

60.3 wt. % K2O.

Granulation of this mixture gave the following composition:

6.87 wt. % of total N,

28.08 wt. % of total P2O5,

19.90 wt. ° / o of the total P2O5 content in the form of ground phosphorus,

8.20 wt. % of the total P2O5 content in the form of ammonium polyphosphates,

71.9 wt. % of the total P2O5 content in the form of ammonium phosphates,

20.62 wt. % K2O,

10.04 wt. % ammonium sulfate.

Example 2

The following raw materials were fed into the process as in Example 1:

7.6 kg / h of concentrated ammonia gas,

38.4 kg / h of extraction H3PO4 containing 52.2 wt. ° / o P2O5,

7.3 kg / h 92.2% H2SO4,

15.0 kg / h phosphorus containing 33.4 wt. %

P2O5,

41.0 kg KCl containing 60.3 wt. % K2O, 0.5 kg natural ground zeolite.

Granulation yielded a product of the following average composition:

6.04 wt. % of total nitrogen,

25.05 wt. % of total P2O5,

20.0 wt. % of the total P2O5 content in the form of ground phosphorus,

6.7 wt. % of the total P2O5 content in the form of ammonium polyphosphates,

73.3 wt. % of the total P2OS content in the form of ammonium phosphates,

24.7 wt. % K2O,

9.02 wt. % ammonium sulfate.

Example 3

The following raw materials were fed into the process in a manner similar to Example 1:

7.6 kg / h of concentrated ammonia,

36.4 kg / h of extraction H3PO4 containing 52.2 wt. % P2O5,

7.3 kg / h 92.2% H2SO4,

15.0 kg / h of ground phosphorus containing 33.4 wt. % P2O5, of a particle size distribution of 80% less than 0,125 mm,

21.5 kg / h KCl containing 61.3% w / w K2O

20.5 kg / h of crystalline ammonium nitrate, granulation gave the product of the following average composition:

13.3 wt. % nitrogen,

25.04 wt. % of total P2O5,

20.0 wt. % of total P2O5 in the form of ground phosphorus,

5.9 wt. % of the total P2O5 content in the form of ground ammonium polyphosphates,

74.1 wt. % of the total P2O5 content in the form of ammonium polyphosphates,

13.2 wt. % K2O,

9,0 wt. % ammonium disseminated,

20.5 wt. % ammonium nitrate.

Example 4

The following raw materials were fed into the process in a manner similar to Example 1:

9.0 kg / h of concentrated ammonia gas,

26.5 kg / h of extraction H3PO4 containing 49.8 wt. ° / o P2O5

24.5 kg / h 72.7% H2SO4

15.0 kg / h phosphorus containing 33.4 wt. % P2O5,

31.0 kg / h K4SO2 containing 53.5 wt. % K2O,

5,5 kg / h ammonium nitrate,

2.0 kg / h ground natural zeolite, granulation gave the product of the following average composition:

9.3 wt. % nitrogen,

18.1 wt. % of total P2O5,

27.6 wt. % of the total P2O5 content as ground phosphorus,

13.9 wt. % of the total P2O5 content in the form of ammonium polyphosphates,

58.5 wt. % of the total P2O5 content in the form of ammonium phosphates,

16.5 wt. «/ O K2O,

24.2 wt. % ammonium sulphate,

5.5. % ammonium nitrate,

2.0 wt. % Zeolite.

Example 5

The following raw materials were fed into the process in the same way as in Example 1:

kg / h of concentrated ammonia gas,

24.5 kg / h of extraction H3PO4 containing 54.2 wt. % P2O5,

23.0 kg / h 93.8% H2SO4

150 kg / h ground phosphorus containing 33.4 wt. % P2O5 granulometric composition 90 wt. % of particles smaller than 0,150 mm,

30.5 kg / h KCl containing 61.1 wt. % K2O, 2.0 kg / h ground natural zeolite, granulation gave a product of the following average composition:

9,0 wt. % nitrogen,

18.4 wt. % of total P2O5,

27.2 wt. % of the total P2O5 content as ground phosphorus,

25.1 wt. % of the total P2O5 content in the form of ammonium polyphosphates,

47.7 wt. ° / o of the total P2O5 content in the form of ammonium phosphates,

18.6 wt. % K2O,

29.0 wt. % ammonium sulphate,

2.0 wt. % zeolite.

Example 6

The following raw materials were fed into the process in the same way as in Example 1:

kg / h of ammonium nitrate ammonium nitrate containing 25.9 wt. % NH5 and 40.6 wt. ° / o total nitrogen,

19.0 kg / h of extraction H3PO4 containing 50.4 wt. % P2O5,

12.5 kg / h 93.8% H2SO4, kg / h ground phosphorus containing 32.7 wt. % P2O5 of a granulometric composition of 80% of particles less than 0,20 mm,

21.5 kg / h KCl containing 61.1 wt. % K2O,

2.5 kg / h of thickened sulphite shavings.

Granulation yielded a product of the following composition:

12.9 wt. % nitrogen,

17.8 wt. % of total P2O5, wt. % of the total P2O5 content in the form of ground phosphorus, % of the total P2O5 content in the form of ammonium phosphates,

13.0 wt. % K2O,

15.7 wt. % Ammonium sulfate.

Example 7

The following raw materials are fed into the process in the same way as in Example 1:

15.5 kg / h ammonium nitrate ammonium nitrate containing 25.9 wt. % NH 3 and 40.6 wt. ° / o total nitrogen,

3.5 kg / h of concentrated liquid ammonia, kg / h of extraction H3PO4 containing 50.4 wt. % P2O5, kg / h 91.8% H2SO4, kg / h ground phosphorus containing 32.7 wt. % P2O5, granulometric composition 80 wt. % of particles smaller than 0.125 mm, kg / h KCl containing 61.1 wt. % K2O,

5.5 kg ground natural zeolite,

2,0 kg sulphite liquor.

Granulation yielded a product of the following average composition:

9.1 wt. % nitrogen,

18.1 wt. ° / o total P2O5,

27.0 wt. % of the total P2O5 content in the form of ground phosphorus,

73.0 wt. % of the total P2O5 content in the form of ammonium phosphates,

18.3 wt. θ / ο K2O

14.8 wt. % ammonium sulphate,

5.5 wt. % natural zeolite.

Example 8

The following raw materials are fed into the process in accordance with Example 1:

8,0 kg / h concentrated ammonia,

26.0 kg / h of extraction H3PO4 containing 52 wt. % P2O5,

12.0 kg / h 92.5% H2SO4

15.0 kg / h of ground phosphorus with a content of 33.1 wt. % P2O5 granulometric composition 80 wt. % of particles smaller than 0,20 mm,

30.5 kg / h KCl containing 60.9 wt. % K2O, 14 kg / h of crystalline ammonium sulphate,

2,0 kg / h of sulphite liquor.

Granulation yielded a product of the following average composition:

8.9 wt. ° / o nitrogen,

18.4 wt. % of total P2O5,

26.9 wt. % of total P2O5 in the form of ground phosphorus,

5.4 wt. % of the total P2O5 content in the form of ammonium polyphosphates,

67.7 wt. % of the total P2O5 content in the form of ammonium phosphates,

18.5 wt. % K2O, wt. % ammonium sulfate.

Claims (2)

Granular multi-component fertilizer containing 4 to 19 wt. % total nitrogen, 13 to 45 wt. % of total P2O5, wherein 35 to 82 wt. % of the total P2O5 content is in the form of ammonium phosphates, 10 to 28 wt. % K 2 O in the form of potassium chloride and / or potassium sulphate and a substance modifying the physicochemical and mechanical properties, characterized in that they contain 5 to 48 wt. % Of P2O5, of the total content of θ2θ5, νο in the form of phosphonates and 0.3 to 45 wt. % Of P2O5 in the form of condensed ammonium phosphates and further contain 7 to 35 wt. % ammonium sulfate. 2. A process for the production of granular compound fertilizers according to point 1, based on the continuous neutralization of rhodophosphoric trihydvinyl phosphate or a mixture of ammonia and / or ammonium nitrate trihydrogenphosphoric acid and / or ammonium nitrate, the product of the neutralizing reaction with the continuous raw material. characterized in that the incorporation of phosphorus into fertilizer granules occurs after contact of the phosphorus particles with the reaction product of high temperature neutralization associated with molecular dehydration of the product having the character of a melt-steam-gas mixture, wherein the degree of conversion of the monophosphate component into to 75% and a temperature of 145 to 395 ° C, wherein the weight ratio of P2O5 in the melt and P2O5 in phosphorus is 0.05 to 0.92.