LT4720B - Method for producing dry granular fertilizer - Google Patents

Abstract

The invention concerns the production of complex granular manure.Complex granular manure is produced through mineral acid neutralization with component compounding ammonia during the mixing process with granular manure components or before the mixing process. The produced suspension is granulated at 45-110 degrees Celsius, dried until residual moisture is between 0.4 - 0.3 %, cooled down to at least 45 degrees Celsius, fractionated so the diameter of the main fraction granules are 1 to 5 mm, optimally 2 to 4 mm. Ammonia, aqua ammonia or ammonia salt is used as component compounding ammonium while mineral acid is sulphur, nitric or phosphate acid. The ammonia component is mixed with one acid or a compound of acids. The amount of components is to be used so the ammonia salt extracted through neutralization of the acid represents at least 10 % of the total weight of nitrogen. The amount of microelements is increased through admixture agents compounding copper, zinc, cobalt, manganese sulphate, carbonates, nitrates, oxides, chelate compounds and molybdates, boracic acid, borates, boron minerals, selenates or iodides, nonferrous metallurgy or other industry waste.

Description

The present invention relates to the bulk compound fertilizer industry and can be used to produce complex nitrogen, phosphorus, potassium (NPK) fertilizers with trace elements.

It is known to produce bulk compound fertilizers from individual fertilizer components by mixing them. Complex fertilizers of various nutrient concentrations and ratios can be obtained by choosing the composition of the bulk components (Sokolovskij A.A., Unanianc T.P. "Kratkij spravočnik po mineralum udobrenija", Moscow, "Chimija", 1977, pp. 310-314). The main disadvantage of such fertilizers is the different size of the granules of the separated components, which causes a very uneven distribution of the soil into the soil and therefore of nutrients. the field distribution is very uneven and the agrochemical efficiency of these fertilizers is greatly reduced.

There is a known method of producing bulk fertilizers from comminuted individual fertilizer components by mixing, moistening with water or steam, followed by granulation and drying (United Nations Development Organization, Fertilizer Manual, 1980, pp. 250-252). The main disadvantage of this method is that it adds a lot of water, which evaporates much of the heat after drying the granules after drying. In addition, NPK fertilizers produce pellets that are not robust enough to shrink during storage and require additional work to crush them before use.

There is a known method in which compound fertilizers are made from the individual components of the fertilizer for crushing by mixing, moistening with water and / or steam and adding crushed clay (U.S. Pat. No. 5,794,9936, priority issued June 7, 1996, published 1998). This method requires additional work in drying, cleaning and crushing the clay and in preparing its aqueous suspension. In addition, the drying of fertilizers requires considerable energy consumption. Pellets. strength is not always sufficient and clay increases the fertilizer ballast by reducing nutrient concentration.

A patented process for the production of bulk compound fertilizers, wherein the bulk fertilizer components are mixed with a mineral acid-ammonia interaction product, granulated, dried, cooled and fractionated. The mineral acids are neutralized with the ammonia-containing component while mixing with the bulk fertilizer or before mixing, granulated at 45-110 ° C, dried to a residual moisture content of 0.4 to 3.0%, cooled to a maximum of 45 ° C, fractionating such that the main fraction granules have a diameter of 1 to 5 mm, preferably 2 to 4 mm.

Uses mineral acids, namely sulfur, nitrogen, or phosphorus, and the ammonia-containing component is ammonia, ammonia water, or ammonia containing water, ammonia, ammonium nitrate, and / or urea. The ammonia-containing component is mixed with one mineral acid or a mixture thereof in molar ratios:

NH ₃ : H ₂ SO ₄ = (1-2): 1 and / or NH ₃ : HNO ₃ = (0.9-1): 1 and / or NH ₃ : H ₃ PO ₄ = (1-3): 1.

The ammonium salt obtained by acid neutralization shall have a nitrogen content of not less than 10% of the total nitrogen content of the product. When the fertilizer granulation water from the ammonium salt slurry (pulp) is not sufficient, then additional water or steam is supplied.

Trace elements are added using materials consisting of copper, zinc, cobalt, manganese sulfates, chlorides, carbonates, nitrates, oxides, chelates and molybdates, boric acid, borates, boron minerals, selenates or iodides, non-ferrous metallurgy or other industries.

Bulk compound fertilizers are manufactured as shown in the technological diagram below.

The bulk fertilizer components are weighed out of the hopper (1) by means of scales (2) and supplied by a mechanical feeder (3, 5) and an elevator (4) to the mixer (6). The fertilizer mixture in the granulator (7) is mixed with the reaction product of ammonia from the container (8) and mineral acid from the container (9). The resulting fertilizer is dried in a dryer (10) by combustion gas from the furnace (11). The bulk compound fertilizer is lifted by means of an elevator (12) to a screen (13), from where the fine fraction is returned to the premixing unit, the bulk fraction is fed to a mill (15) where it is crushed and returned to the screen (13). The standard fraction is supplied to the cooler (14), from which the chilled product is taken to a warehouse for storage or packaging. In order to add trace elements to the fertilizers produced, they are loaded into the hopper (1).

The following raw materials may be used in the production of patented compound fertilizers:

ammonia liquid with not less than 82,0% nitrogen;

ammonia water containing at least 20.5% nitrogen;

ammonium sulphate containing 20,8% or more nitrogen;

ammonium nitrate containing 34,0% or more nitrogen;

ammonia containing at least 26,0% nitrogen;

urea containing at least 46.0% nitrogen;

superphosphate simple with an absorbable P ₂ 0 _{5 of} about 20%;

phosphorus powders with a P ₂ O _{5 content} of 19% or more;

double superphosphate containing not less than 41% of absorbable P ₂ O ₃ ;

amofos containing at least 11% nitrogen and 45% P ₂ O ₃ ;

diammoniophosphate containing not less than 19% nitrogen and 49% P ₂ O ₅ ;

potassium chloride containing 85% or more by weight of potassium chloride;

potassium sulphate containing not less than 46% of K ₂ O;

potassium magnesium (about 9% Mg O), containing not less than 28% K ₂ O;

nitric acid containing 55% or more HN0 ₃ ;

phosphoric acid containing at least 50% P ₂ O ₅ ;

sulfuric acid of a concentration of 90% or more.

The technical characteristics of compound fertilizers can be determined in the following ways:

nitrogen mass,% - by photochromimetry, formaldehyde, Keldahl;

mass of phosphorus,% - by photochromimetry;

mass of potassium,% by flame photometer;

mass of calcium,% - complexonometric;

mass of magnesium,% - by complexonometric;

fraction size,% by special sieves;

pellet strength, g / gran - with a special gauge.

The invention is illustrated by the following examples.

example. 459 g of ammonia containing 12% ammonia, 52% ammonium nitrate and 36% water are neutralized with 158 g of 96% sulfuric acid (NH ₃ : H2SO4 = 1.95: 1). The resulting slurry was mixed with 260 g of monoammonium phosphate and 267 g of potassium chloride. The resulting NPK fertilizer is granulated, dried at 80 ° C and then fractionated. The nitrogen content of the ammonium salt obtained by acid neutralization is 29%.

example. 348 g of ammonia, as in Example 1, neutralize 120 g of 98% H ₂ SO ₄ (NH ₃ : H2SO 4 = 2: 1), mix the slurry with 348 g of diammonium phosphate and 267 g of potassium chloride. The resulting NPK fertilizer is granulated, dried at 100 ° C and then fractionated. The nitrogen content of the ammonium salt obtained by acid neutralization is 21,75%.

example. 323 g of ammonia containing 62% ammonium nitrate, 18% ammonia and 20% water neutralize 167 g of 92% sulfuric acid (NH ₃ : H ₂ SO 4 = 1.98: 1). The column is mixed with 260 g of monoammonium phosphate and 267 g of potassium chloride.The fertilizer is granulated, dried at 65 ° C and then fractionated. The nitrogen content of the ammonium salt obtained by acid neutralization is 29.17%.

example. 245 g of ammonia, as in Example 3, neutralize 126 g of 98% concentration of sulfuric acid (NH 2 SO 2 = 1: 1). The column is mixed with 348 g of diammonium phosphate and 267 g of potassium chloride. The fertilizer is granulated, dried at 85 ° C and fractionated. The nitrogen content of the ammonium salt obtained by acid neutralization is 21.4%.

example. 149 g of ammonia, as in Example 3, is neutralized with 275 g of 56% concentration of orthophosphoric acid (NH ₃ : H ₃ PO 4 = 1: 1). The column is mixed with 348 g of diammonium phosphate and 267 g of potassium chloride. The resulting NPK fertilizer is granulated, dried at 110 ° C, fractionated. The nitrogen content of the ammonium salt obtained by acid neutralization is 17.3%.

The fertilizers produced according to these samples were analyzed, their physico-chemical properties were evaluated and the results of the analysis are presented in the table.

Composition and physico-chemical properties of bulk complex NPK fertilizers

Pavyz- dys Nutrient Concentration, % Humid- meat quantity, % Fractional content of granules,% Gran ls strong mas, g / gran N P2O5 K ₂ O S <1 mm 2-4 mm > 4 mm 1 15.6 15.7 16.0 5.0 3.0 4.0 89.0 7.0 1930 O 15.8 16.0 16.1 4.0 2.9 3.0 92.0 5.0 2110 3 16.4 16.6 16.6 5.4 1.1 5.0 90.0 5.0 2425 4 16.9 17.1 17.1 45 1.6 5.0 91.0 4.0 2310 5 12.7 29.4 17.0 - 2.5 3.5 89.0 7.5 2160

The analytical data in the table show that the production of compound fertilizers using ammonia containing 27.6% nitrogen (Examples 1 and 2) has a higher moisture content (2.9 and 3.0%) and the lowest pellet strength (1930 and 1930). 2110 g / gran). Complex fertilizers obtained with ammonia containing about 40% nitrogen are more robust, contain mostly optimal fraction of pellets 2-4 mm in diameter, slightly (1-2%) higher concentration of nutrients (N, P, K), less moisture ( 1.1-1.6%).

Neutralization of ammonia with phosphoric acid (Example 5) results in compound fertilizers with the highest concentration of phosphorus (29.4% Ρ ₂ Ο ₅ ), but with a medium pellet strength (2160 g / gran). and the sum of potassium concentration (48.0-59.0%) compared to known mineral fertilizers such as nitrofoska. Nitrophos contains 11% nitrogen, phosphorus and potassium oxides, about 1.5-2% moisture, and the main fraction has a pellet strength of 2000 to 2300 g / gran. Patented fertilizers contain up to 5.0% sulfur, a much needed secondary macronutrient.

Patented fertilizers extend the range of complex fertilizers and applications in agriculture, while the production of the fertilizer itself is more economical and environmentally friendly.

Claims (6)

DEFINITION OF INVENTION 1. A method of producing a bulk compound fertilizer comprising mixing the bulk fertilizer components with an ammonia-mineral fertilizer interaction product, granulating, drying, cooling and fractionating, characterized in that the mineral acid is neutralized with the ammonia-containing component by mixing with the bulk fertilizer or before mixing. At a temperature of 110 ° C, dries to a residue of 0.4% to 3.0% moisture in the product, cools to a temperature of not more than 45 ° C, fractionates such that the main fraction granules are 1 to 5 mm in diameter, preferably 2 to 4 mm in diameter. mm. 2. A process according to claim 1, wherein the ammonia-containing component is mixed with the mineral acid in a molar ratio: NH ₃ : H ₂ SO ₄ = (1-2): 1 and / or NH ₃ : HNO ₃ = (0.9-1): 1 and / or NH ₃ : H ₃ PO ₄ = (1-3): 1. 3. A process according to claims 1 and 2, wherein the ammonia-containing component is ammonia, ammonia water or ammonia containing water, ammonia, ammonium nitrate and / or urea, and the mineral acid is sulfuric, nitric or phosphoric acid. 4. A process according to claims 1, 2 and 3, wherein the ammonia-containing component is mixed with one mineral acid or a mixture thereof. 5. A process according to claims 1, 2, 3 and 4 wherein the amount of the components is selected such that the ammonium salt obtained by acid neutralization has a nitrogen content of at least 10% by weight of the total nitrogen. 6. A process according to claim 1, wherein the trace elements are mixed using materials consisting of copper, zinc, cobalt, manganese sulfates, chlorides, carbonates, nitrates, oxides, chelates and molybdates, boric acid, borates, boron minerals, selenates or wastes from iodides, non-ferrous metallurgy or other industries.