RU2221760C1 - Process of production of mixed fertilizers with trace minerals - Google Patents

Abstract

FIELD: fertilizers. SUBSTANCE: process is characterized by preliminarily mixing trace minerals followed by mixing them with phosphorus-, potassium-, and nitrogen- containing components. Resulting mix is tableted at pressure 10 to 150 MPa and moisture content 0.3 to 3.4%. Particular trace minerals are represented by compounds of manganese, copper, zinc, cobalt, and molybdenum, which are mixed at weight ratio (10-50):(5-20):(4-10):(2-6): 1, respectively. Weight ratio ammophos/potassium chloride/urea/trace mineral mixture is as follows: (1.68-3.36):(1.40-2.85):(0.95-3.11):1, respectively. EFFECT: improved quality and agrochemical efficiency of fertilizers, and simplified production technology. 2 cl, 2 ex

Description

 The invention relates to the chemical industry, in particular to methods for producing complex fertilizers with microelements, and can be used in the production of mineral fertilizers.

 A known method of producing complex-mixed fertilizer, which consists in the fact that trace elements are introduced into the main fertilizer by mechanical mixing of powdered mineral fertilizers with additives containing trace elements (A. S. 711028, class C 05 D 9/02, 1980) . The disadvantage of this method is inherent to all quality fertilizers obtained as a result of mixing the powder components, such as caking and segregation, i.e. separation of components in mixtures.

There is also known a method of producing granular complex fertilizers with microelements, comprising mixing granular components containing nitrogen, phosphorus, potassium with microelements, in which microelements are pre-mixed with calcium-, sulfur-containing substances, the resulting mixture is granulated at a moisture content of 10-20% and a temperature of 50-70 ^o C to obtain granules with a size of 1-4 mm, and then granules in an amount of 10-25 wt.% of the total weight of the fertilizer are mixed with granular nitrogen, phosphorus and potassium-containing components (Patent RU, 2142444, class C 05 D 9/02, CL C 05 G 1/06, 1999).

 The closest to the claimed technical essence and the achieved result is a method of producing complex fertilizers with microelements, including mixing the starting components and tableting the resulting mixture, in which the technological operations are carried out in the following sequence: separation of the source nitrogen, phosphorus, potassium-containing components into two fractions with sizes respectively 0-0.5 mm and 0.5-15 mm, rolling the smaller of them while drying and mixing with a solution of trace elements and subsequent mixing with rupee fraction in the selected range of parameters (Patent RU, 2074156, class C 05 D 9/02, 1997).

 The main disadvantage of this method is the complexity and multi-stage technological processes, the presence of operations carried out at elevated temperatures, leading to an increase in energy consumption and a decrease in environmental safety.

 The objectives of the invention are to improve the quality and agrochemical effectiveness of complex mineral fertilizers with trace elements by improving their physico-mechanical properties and simplifying the technology for producing these fertilizers.

 The method in accordance with the invention is that the mixture is prepared by mixing the starting ingredients with trace elements, then the mixture is tabletted by compression at a pressure of 10-150 MPa and a moisture content of the mixture of 0.3-3.5%.

 Trace elements are pre-mixed in a mixer, into which they are loaded through a roller crusher and a batcher. The loading of trace elements can be carried out in mass ratios in the ranges of Mn: Cu: Zn: Co: Mo = (10-50): (5-20) :( 4-10) :( 2-6): 1.

 As micronutrient additives, their soluble salts are used. The ratio of trace elements in the prepared fertilizer depends on their content in the soils of the region of consumption and the type of agricultural crop for which the fertilizer is intended. The concentration ranges of each trace element are determined taking into account the analysis of the composition of the main soil types in Russia and the CIS.

 Phosphorus, potassium, and nitrogen-containing components (PKN components) in the form of ammophos, urea, and potassium chloride are taken as starting ingredients. PKN components are fed by feeders to roller crushers and, after the necessary grinding, they are transferred to metering hoppers for ammophos, potassium chloride and urea, respectively. Then, in one mixer, all the ingredients are mixed with microelements, which can also be carried out in various mass ratios, which makes it possible to obtain a wide range of fertilizers, namely: ammophos: potassium chloride: urea: trace element mixture = (1.68-3.36) : (1.40-2.85) :( 0.95-3.11): 1.

 Mixing the starting ingredients with trace elements is carried out for 0.5-1 hours. Then, the resulting mixture is fed from the mixer into a tablet-pressing machine, in which the tablets of the finished fertilizer are pressed in a constant mode. Optimum caking and segregation indices for the finished product are ensured at a pressure of 10-150 MPa and a moisture content of a charge of 0.3-3.5%.

 The choice of specific pressing modes is determined by the following factors. At a pressure below 10 MPa, the fertilizer tablets do not retain their shape after pressing, but an increase in pressure above 150 MPa is impractical, since this causes the destruction of the tablets. Pressing with a moisture content of a charge of less than 0.3% leads to an increase in its hygroscopicity, and with a moisture content of a charge of more than 3.5%, the caking of the fertilizers increases sharply.

The final product obtained by this method is a tablet with a diameter of 9 mm and a thickness of 7 mm and has the following physical and mechanical properties:
- humidity 0.2-0.6%;
- mechanical strength of 6.5-7.5 MPa;
- porosity 0.05-0.06;
- caking 10-15 kPa;
- hygroscopicity coefficient of 3.3-3.6 mol / kg.p;
- hygroscopic point 60-65%.

 High agrochemical properties of the resulting fertilizer are due to the presence in it of appropriate quantities of the following nutrients: nitrogen, phosphorus pentoxide, potassium oxide, manganese, copper, zinc, cobalt, molybdenum, sulfur.

 Preliminary grinding of all components to the same degree ensures uniform distribution of micro and macro components in tablets.

The method is illustrated by the following examples.
Example 1. For typical gray earths of the Middle East and Central Asia, where the main crops are cotton, grapes, a complex fertilizer with trace elements is prepared as follows.

After grinding in roll crushers to the required degree, 327.8 kg of ammophos, 278.6 kg of potassium chloride, 272.6 kg of urea and 121 kg of a mixture of trace elements are loaded into the mixer through dispensers. This amount is necessary to obtain 1 ton of the finished product. The mass ratio of phosphorus, potassium, nitrogen-containing components and a mixture of trace elements is 2.71: 2.30: 2.25: 1. The mixture of trace elements is prepared in advance in a separate mixer, which is pre-loaded with 74 kg of manganese sulfate, 20 kg of copper sulfate, 15 kg of zinc sulfate, 10 kg of cobalt sulfate and 2 kg of sodium molybdenum acid, while the mass ratio of trace elements is Mn: Cu: Zn: Co: Mo = 21.1: 6.4: 4.3: 2.6: 1. Trace salts are mixed for 0.5 hours and then transferred to a mixer, where ammophos, potassium chloride are already located urea. Mixing the mixture is performed within 1.0 hour. From the mixer, the resulting mixture is fed into a tablet-pressing machine, in which the finished fertilizer is pressed in constant mode at a pressure of 50 MPa and a moisture content of the charge of 2.5%. The final product is a white tablet with a diameter of 9 mm and a thickness of 7 mm and has the following physicochemical properties:
- mechanical strength of 6.5-7.2 MPa;
- porosity 0.056;
- caking 10-15 kPa.

 The nutrient content in the finished fertilizer: nitrogen - 16.5%, phosphorus pentoxide - 16.5%, potassium oxide - 16.5%, sulfur - 1.6%, manganese - 1.7%, copper - 0.5% , zinc - 0.3%, cobalt - 0.2% and molybdenum - 0.1%.

 Example 2. Complex fertilizer with microelements for sod-podzolic soils of the Leningrad region, where the main crops are potatoes and root crops.

 To obtain 1 ton of the finished fertilizer, 342 kg of ammophos, 253 kg of potassium chloride, 253 kg of urea, previously crushed to the required degree in roller crushers, and 152 kg of the trace element mixture, which is 2.25: 1 in mass ratio, are loaded into the mixer through dispensers 66: 1.66: 1. The trace element mixture is prepared in advance in a separate mixer, which is preloaded with 44.3 kg of manganese sulfate, 67.2 kg of copper sulfate, 18 kg of zinc sulfate, 20 kg of cobalt sulfate and 2.5 kg of molybdenum sodium sour. The mass ratio of trace elements Mn: Cu: Zn: Co: Mo = 10.1: 17.1: 4.1: 4.2: 1. The salts of trace elements are mixed for 0.5 hours and then transferred to a mixer, which contains the rest ingredients necessary for the preparation of the mixture. Mixing the mixture is carried out for 0.75 hours. From the mixer, the resulting mixture is fed into a tablet-pressing machine, where the finished fertilizer is pressed continuously at a pressure of 40 MPa and a moisture content of the mixture of 3.0%.

The final product is a pale blue tablet with a diameter of 9 mm and a thickness of 7 mm and has the following physical and mechanical properties:
- mechanical strength of 6.7-7.5 MPa;
- porosity 0.052;
- caking 10-15 kPa.

 The nutrient content in the finished fertilizer: nitrogen - 16.2%, phosphorus pentoxide - 18.7% potassium oxide - 15%, copper - 1.7%, sulfur - 1.45%, manganese - 1.08%, cobalt - 0.4%, zinc - 0.4% and molybdenum - 0.13%.

Using the claimed technical solution ensures the achievement of the following advantages compared with all known objects of similar purpose:
- simplicity of the process, the possibility of automation;
- lack of lengthy operations, such as drying the product;
- lack of operations using high temperatures, aggressive reagents, increasing the safety of production;
- the minimum amount of ventilation emissions, the possibility of organizing a virtually waste-free environmentally friendly production;
- reducing the overall dimensions of technological equipment in comparison with equipment for mixing reagents in liquid phases, reducing the cost of manufacturing the final product.

Obtained by the claimed technology, fertilizers have the following advantages in comparison with analogues:
- increase crop yields by 12-20%;
- during storage, they do not cake and maintain a uniform physicochemical composition, the optimal parameters of which for soils of a particular region can be selected relatively simply and quickly.

 The application of the claimed solution as a whole allows simple technological methods using affordable and environmentally friendly components to organize directly at the consumer the production of high-quality fertilizer with practically no waste technology.

Claims (2)

1. A method of producing complex fertilizers with microelements, comprising mixing the initial phosphorus, potassium and nitrogen-containing components with microelements and tableting the resulting mixture, characterized in that soluble compounds of manganese, copper, zinc, cobalt and molybdenum are used as microelements, the microelements are pre-mixed in a mass ratio of Mn: Cu: Zn: Co: Mo = (10-50) :( 5-20) :( 4-10) :( 2-6): 1, after which it is mixed with phosphorus, potassium and nitrogen-containing components and pressing during tableting is carried out at a pressure of 10-150 MPa and the moisture content of the mixture of 0.3-3.5%. 2. The method according to claim 1, characterized in that the mixing of phosphorus, potassium and nitrogen-containing components and a mixture of trace elements is carried out in a mass ratio: Ammophos 1.68-3.36 Potassium chloride 1.40-2.85 Urea 0.95-3.11 A mixture of trace elements 1