CS272727B1 - Method of granulated multi-component fertilizers production - Google Patents

Abstract

The invention concerns a method of production of granulated multi-component fertilisers based on the chemical reaction of compounds, which are a source of plant nutrients, with the simultaneously continuous production of granules. The source for the predominant part of phosphate components is a product of the reaction of ground phosphorite and extractive trihydrogen phosphate acid prepared in the presence of sulphatic anions, in which the share of phosphoric oxide from the extractive trihydrogen phosphate acid and ground phosphorite is between 0.6 : 1 to 2.3 : 1, whilst the amount of water drawn into the reaction mixture by all the reaction components corresponds to 5.5 to 34.5 of the percentage weight of the whole reaction mixture and the total content of sulphatic anions drawn into the decomposing reaction represents 0.3 to 9.8 of the percentage weight of the whole reaction mixture. The source of nitrogen components is ammoniac of ammonium nitrate and/or ammoniac and/or ammonium sulphate. The source of potassium components is potassium chloride or sulphate. Sulphuric and/or phosphoric acid are further added to the technological process at a quantity at minimum corresponding to neutralisation of the free ammoniac drawn into the system.

Description

The present invention relates to a process for the production of granular multi-component fertilizers based on the chemical reaction of the constituents with simultaneous granular formation.

Industrial fertilizers represent an important intensification factor of crop production and, in relation to other factors, influence the results of crop production to 30%. The high intensity of fertilization is connected with the necessity of effective spending of resources in this area, therefore, especially for economic reasons, there will be no substantial increase in the rates of industrial fertilizers in the near future. In terms of foreign exchange intensity, phosphorus fertilizers are a significant burden for our economy, for which it is necessary to count on the entire quantity of phosphates - phosphorous, phosphoric acid, intermediates or finished products by import, mostly from non-socialist countries. Therefore, in addition to assessing the agro-biological properties of individual types of phosphorous raw materials and phosphate fertilizers, it is necessary to increasingly assess their foreign exchange intensity.

The different exchange rate of the individual phosphorous raw materials was one of the reasons why the production of micronized phosphorites in the volume of 60 kt θ2θ5 · in the target year is also considered in the ČSSR.

The urgency of using fertilizers with a higher phosphorus content in a gradually effective form, which may be ground phosphorus, is also due to the fact that the application of soluble phosphorus fertilizers to the soil results in precipitation and adsorption processes (SAMPLE, EC - SOPER, RJ - RACZ). , G. 3 .: Reation of Phosphate Fetilizers in Soils, Chapter 11 in The Role of Phosphorus in Agriculture Madison, WI 53 711,

USA 1980; MICHALÍK, I .: Intake and Metabolism of Phosphorus in Plants. Agriculture 2/85, Series A, VEDA-Publisher SAS, Bratislava 1985) in the first year depending on pedological characteristics of the pod, cultivated crop type, hydro-climatic conditions, type and quantity of other biogenic elements in the pod, depending on the method and quality on average, it uses only 10 - 40% of the cultivation of the soil and the amount of organic fraction in plants (ENGELSTAD, 0 P. - TERMAN, GL: Agronomy of Effectiveness of Phosphate Fertilizers., Chepter 11 in The Role of Phosphorus in Agriculture, Madison, WI 53 711, USA 1980; Anonymous: Handbook on Phosphate Fertilization (SMA Ltd. 28 rue Marbeuf, 75,008 Paris). ’’ ·

The main disadvantage of the use of ground phosphites is the uncertainty of their agronomic efficiency, especially in the first year after their application and also their problematic handling and application of the finely ground powdered material.

According to the data of the Fertilizer Manual (Development and Transfer of Technology, Series No. 13, UNIDO, New York 1980), in order to ensure good agronomic efficiency of ground phosphites when used directly, it is necessary to ensure their finely ground to 90% by weight. . % of the milk phosphorite particles is less than 0.147 mm, or preferably of greater agronomic efficiency, to at least 80 wt. % of the particles were smaller than 0.043 mm. A limited quantity of micronised phosphite, sold under the trade name Hyperphosphat, is imported into Czechoslovakia. It is Tunisian phosphorus Gafsa ground to a fineness of 90% by weight. % overflow through the sieve 0.063 mm.

PECINA states in his candidate thesis (VŠZ, 1966) that with the phosphorus of Tunisia, ground to a fineness below 0.06 mm, up to 90% of the efficiency of the phosphorus component contained in superphosphate can be achieved in the first year of exposure. the efficiency of the phosphorus component of phosphite even higher.

Granulation of the ground phosphorites resolved the problems associated with the handling of fine and consequently considerable dusty material, but the treated product exhibited less agronomic efficiency because the granulation significantly reduced the contact surface of the ground phosphorous particles with the aqueous solution.

Another disadvantage is the difficult granulation of ground phosphites, which is practically not possible without the use of suitable binders.

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Adla. P. Thiring (paper presented at the 6th Congress of AGRICHEM Chemistry in Agriculture, Bratislava - June 1984), it is advantageous to realize the granulation of ground phosphorites in a plant consisting of two successive parts - a preliminary granulator and a so-called pre-granulator. coating granulator. Advantageously, according to the author, granules can also be prepared without the use of binders, using only water and steam. The disadvantage is that the technological process needs to be carried out in two stages, using special equipment.

Another known possibility of wider application of ground phosphites in agricultural practice is their incorporation into granular NPK and NPK fertilizers by the process of so-called. tanler granulation. Fertilizers of this type prepared by a modified process of so-called. melt granulation using so-called melt granulation; of the cross reactor incorporated into a short larger diameter granulation drum are also subject of AO no. 254 028 (PV 8771-85) and AO no. 254,029 (PV 8772-85). These products, by their nature and chemical composition, eliminate the reduction of the agronomic efficiency of the phosphorous component of ground phosphites due to the reduction of the contact surface of the particles with the aqueous solution.

The difficulty of granulating phosphite is also documented by the fact that even the world's leading suppliers of so-called pressure granulation - compaction (BARLOY, M: Granulation d'Engrais for Compactage - Procede ABC, Seminaire sur les tendances et evolution de Industries des engrains, Istanbul, Turquie 1985), which is currently used mainly in connection with granulation of difficult granular materials, not mentioned in available materials of formulation of industrial fertilizers with a higher proportion of finely ground phosphorites.

The difficulty and limited possibilities of granulating finely ground phosphorites are also confirmed by the results of the actual experimental work, and it was found that pressure granulation of finely ground phosphorites is only possible after their homogenization with some other materials.

In the production of granular multi-component fertilizers Integrated technology uses a process whereby the neutralization reaction of free ammonia from ammonium nitrate ammonium nitrate with sulfuric acid is combined with the formation of granules, in addition to the liquid raw materials mentioned above, also potassium chloride is added to the process and also the superphosphate powder source. - single, enriched or triple superphosphate according to the type of granular fertilizer produced.

It follows that the product - granular fertilizer is made up predominantly of physiologically acidic components, which decreases its agronomic value (PIERRE, WH: Determination of Equivalent Acidity and Basicity of Fertilizers, Industrial and Engineering Chemistry - Vol. 5, p. 229-234 (1933). With regard to the efficiency of the phosphorus component used, these disadvantages are related to the high content of the water-soluble form of phosphorus, which has already been discussed.

It has now been found that, in order to eliminate these problems, the method of producing granular multi-component fertilizers can be so-called. integrated technology significantly rationalize.

This process for producing granular compound fertilizers, based on the chemical reaction of ammonium nitrate ammonium and / or ammonia with at least one mineral acid, wherein the simultaneous granular formation occurs in the presence of a granulation process of the dosed phosphorus component, potassium and / or potassium sulphate and / or sulphate ammonium, the phosphorus component fed to the granulation process is a chemical reaction product of ground phosphorous and extractive trihydrogenphosphoric acid prepared in the presence of sulphate anion, in which the ratio of phosphorus from extractive trihydrogenphosphoric acid and ground phosphorous is equal to 0.6: 1 to 2.3: 1 and the total content of the sulphate anions to be decomposed is 0.3 to 9.8 weight percent of the total acid phosphate reaction mixture. Sulfuric acid and / or phosphoric acid is added to the granule formation process in an amount corresponding at least to neutralization of the free ammonia introduced into the granulation process.

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Sulfuric acid or ammonium sulphate, preferably ammonium sulphate formed as a byproduct from the production of caprolactam and / or methacrylate, or ammonium sulphate formed in the production of special green-based products, may be used as the source of sulphate anion prior to the reaction of the ground phosphorus skSlice from titanium white.

The production and use of granular compound fertilizers within the meaning of the invention has several advantages over the types of similar products produced today;

- Prerequisites for the rational use of the limited and cost-effective concentrated phosphorous raw materials and intermediate products are being created.

- Saving part of phosphoric acid, resp. of superphosphate, the production cost of the production of granular multicomponent fertilizers can be reduced.

- Final products contain along with the starting dose of water-soluble phosphorus also phosphorus in an invariably accessible form, which is thus more resistant to retrogradation in the medium of the additive solution.

- Fertilizer has reduced physiological acidity.

- The realization of the production method in the plants of integrated technology of granular multicomponent fertilizers with the existing powder superphosphate production requires at least the costs of additional machinery and apparatuses.

The production method according to the invention is in existing production plants of granulated multi-component fertilizers based on the so-called " integrated technology quickly feasible.

- The production process is characterized by a high level of operational reliability.

The following examples illustrate and illustrate but do not limit the invention in any way.

Example 1

In an operating experiment, a drum granulator equipped with a hose steam distribution of liquid raw materials (ammonium nitrate ammonium nitrate and sulfuric acid) was dosed on average per minute;

168.5 kg of powdered phosphorus product of the reaction of ground rock phosphate provenance Morocco (32% of P ₂ 0 ₅₎ ^of extraction H + POP 52% of the P ₂ 0 ₃ (in the presence of sulfate anion, where the amount of P ₂ 0 _5, and phosphorous acid was equal to 1.3 and the phosphorus product prepared under these conditions contained 2.48% by weight of free P ₂ O 3, 20.61% by weight of water-soluble P ₂ O ₃ , 22.17% by weight of citrosoluble P ₂ 0 ₃ , 36.67 wt% total P ₂ O ₅ , 11.40 wt%,% moisture (drying at 105 ° C);

79.3 kg of potassium salt (60% K 2 O);

778.0 kg of recycled material (recoverable after separation of undersize and disintegration of the oversize fraction of the granulation mixture) and over 3 pairs of hose distributions, an average of:

46.7 kg of ammonium nitrate ammonia. min. ^_ l, containing:

25.88 wt. % free ammonia

55.34 wt. % NH ₄ NO ₃ a

40.71 wt. % of total nitrogen;

38.9 kg 92% H ₂ S0 ₄ ·

Under the above conditions, an average of 20 tonnes of granulated NPK fertilizer was obtained per hour, characterized by a weight ratio N: P ₂ O = K ₂ O = θ> 3: 1: 0.77, in which the ratio of phosphorus pentoxide soluble in 2% aqueous acid solution of lemon to water-soluble P ₂ O 3 was equal to 1.15.

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Example 2

The average tubing reactor flowing into the drum granulator was fed with an average of:

31.9 kg. h ^_ ^ l extraction HgPO containing 52.2 wt. % of total P ₂ 0g

6,0 kg. h ^_1 92.3% strength H ₂ S0 ₄ and

6,4 kg. h l l of concentrated ammonia gas.

The vapor-liquid mixture produced in the pipe reactor was sprayed into a model granulator of the drum structure, into which, in addition to the return material, so-called " a recycle consisting of a mixture of disintegrated coarse and fine grain fractions,

65.0 kg. h ^-1 phosphorus product of the decomposition reaction of a continuously drawn African ground rock phosphate extraction with H ^ PO ^, in the presence of sulfuric acid (20 wt. parts of MH-H ₂ S0 ₄ per 100 wt. parts of HgPOp tq, where the amount of P ₂ 0 g of H + PO ^ and phosphorous was about 0.8: 1 and the thus prepared phosphorus product contained 37.5 wt.% of ^P 2 ⁸ 5 "L IR ^r c ^r the proportion of water-soluble component of the total phosphorus in the product was 48.8% and going crazy 78.3 kilograms. h ^_1 potassium.

The granular NPK fertilizer thus prepared contained 1.45 times more phosphorus in the citrate-soluble form than the proportion of phosphorus in the water-soluble form.

Claims (2)

OBJECT OF THE INVENTION Process for producing granular compound fertilizers based on the chemical reaction of ammonium nitrate ammonium and / or ammonia with at least one mineral acid, wherein the simultaneous granular formation occurs in the presence of a granulation process of the metered phosphorus component, potassium chloride and / or potassium sulphate and / or ammonium sulphate characterized in that the phosphorous component fed to the granulation process is a chemical reaction product of ground phosphorous and extractive trihydrogenphosphoric acid prepared in the presence of sulphate anion, wherein the ratio of phosphorus from extractive trihydrogenphosphoric acid and ground phosphorous is equal to 0.6: 1 to 2.3: 1 and the total content of the sulphate anions to be decomposed is 0.3 to 9.8% by weight of the total amount of acidic phosphate reaction mixture, with sulfuric acid being added as a mineral acid to the granule formation process and / or phosphoric acid in an amount corresponding to at least neutralization! free ammonia introduced into the granulation process.