RU2804199C1 - Method for granulating highly effective organomineral fertilizer biohumus - Google Patents

Abstract

FIELD: fertilizers.

SUBSTANCE: invention relates to a technology for producing granular organomineral fertilizer vermicompost with increased strength characteristics and can be used in rural industry to increase and restore the physical and chemical properties of the soil and increase the total humus content. The method includes mixing the initial mass of the substrate with a binding solution, granulation using the rolling method, drying and sieving the granulated product with separation of a commercial fraction of 3.0-6.0 mm. Moreover, when mixing the initial mixture of organomineral fertilizer vermicompost, an aqueous solution of sodium bicarbonate with a concentration of 20–30% and a content in the mixture of 6–8 wt.% is used as an inorganic binder; before granulation, the initial mixture is preformed in an extruder through a matrix with a die size of 7 mm. Next, granulation is carried out at a temperature of 25-50°C, drying at a temperature of 90-100°C, when sifting the finished granular product, part of the substandard fraction less than 3.0 mm is crushed and fed to the mixing stage as a retour with a content of 2-4 wt.%.

EFFECT: development of a method for granulating highly effective organomineral fertilizer vermicompost, which makes it possible to obtain granules with high strength and rheological characteristics, such as static and dynamic strength of granules, abrasion, caking, hygroscopicity, reducing the cost of the resulting fertilizer.

1 cl, 1 tbl, 10 ex

Description

The invention relates to a technology for producing granular organomineral fertilizer vermicompost, which has a prolonged action effect with increased quality characteristics of the granular product and can be used in rural industry to increase and restore the physical and chemical properties and fertility of soils.

There is a known method for granulating organomineral fertilizer based on peat. The process begins with preparing the initial mixture: sifting, grinding the particles to a size of 1–2 mm and treating with alkali (NaOH or KOH). Propionic acid is added to the substrate in order to achieve the antibacterial effect of the fertilizer. Starch is used as a binder, the most preferred being corn starch. The resulting mixture is granulated by extrusion using a die with a die size of 4 mm. Next, the granules are dried in a stream of heated air at a temperature of 200–400 ^o C, after which the granules are unloaded from the dryer, cooled and left for 1–8 hours to harden [patent No. 2699263 Canada, publ. 05/28/2007].

The disadvantage of this known method is the heat treatment mode of the material, where the action of high temperatures will lead to the decomposition of the main component of the fertilizer, humic and fulvic acids of peat and propionic acid used as an antifungal additive. When the organic component of the fertilizer decomposes, the structure of the resulting granules may degrade as a result of the release of gas compounds that initiate the formation of cracks, which contributes to the destruction of the structure of the granules and a decrease in strength characteristics. Including the excessive use of fertilizer containing starch, it can become a food product for pathogenic microorganisms and pests.

There is a known method for producing granular organomineral fertilizer based on sapropel from the Tomsk deposit with the mineral additive of ammonium nitrite. The sapropel mass is pre-dried at a temperature of 105 ^o C, then crushed and thoroughly mixed with ammonium nitrate. Granulation is carried out on a disc-type granulator with a rotation speed of 28 rpm and an inclination angle of 45 ^o . Water is used as a binder. The resulting mixture is loaded into a granulator and rolled for 15 minutes. Next, the finished granules are dried at a temperature of 105 ^o C. As a result of granulation, granules with a diameter of 4–5 mm are obtained [RF Patent No. 2515293].

The disadvantage of this fertilizer is the likelihood of containing ballast substances, as well as heavy metals in the sapropel composition, which sharply reduces the activity of the fertilizer and leads to a negative impact on the soil microflora.

There is a known method for producing organomineral fertilizer which contains humic acids, mineral additives of calcium carbonate and calcium oxide to regulate the pH level of the soil and the bacteria Bacillus subtilis and/or Bacillusmegaterium. According to this method, a mixture of calcium carbonate, calcium oxide and bacteria dissolved in water is prepared, then the finished mixture is granulated. Then the resulting granulate is sprayed with humic acids in a ratio of 1:1 and granulation is carried out at a temperature of 70 ^o C in a disc granulator until granules of 3–8 mm are formed. Afterwards, the granulate is dried at 200 ^o C for 10 seconds, after which the temperature is reduced to 70 ^o C and the product is dried to a moisture content of 3% [patent No. 2008/094059 Poland, publ. 07.08.2008].

The disadvantage of this method may be a violation of the established time for dehydration of granules at 200 ^o C, which can lead to the death of bacteria, resulting in a decrease in the desired effectiveness of the fertilizer. An increase in the number of bacteria in the fertilizer promotes their active reproduction, which can lead to acidification of the soil. In particular, the use of bacterial strains in fertilizer sharply reduces the duration of its storage. Residual moisture in the material can negatively affect the integrity of the granules and the quality of the fertilizer, since violation of storage conditions will render the fertilizer unusable.

There is a known method for producing granular organomineral fertilizer based on animal waste. According to this method, a mixture is prepared consisting of animal waste 75%, wt., and gypsum 25%, wt. (which is administered as a suspension). Gypsum is used as a binder and mineral enrichment additive. Mixing of these components is carried out for 4 hours for more uniform mixing. When obtaining this fertilizer, the method of forming the mixture into granules is used by pressing it through holes, the diameter of which is determined by the stated requirement for the size of the granules [US patent 9376349, publ. 03/03/2016].

The disadvantage of this method is the lengthy process of mixing the initial mixture for granulation, which entails additional energy costs at the stage of preparing the fertilizer mixture. The use of non-fermented raw materials leads to a deterioration in the quality of the product, since the fertilizer may contain various pathogenic microorganisms. The resulting granules, through pressing, cannot have high strength characteristics that would ensure the ability to maintain the integrity of the granules during transportation.

There is a known method for producing granular fertilizer mixtures by mixing urea with one or more mineral and organic fertilizers selected from the range of ammonium nitrate, ammonium sulfate, ammophos, diammonium phosphate, potassium chloride and sulfate, phosphate rock, biohum, potassium humate, peat with a urea content in the mixtures of 0. 1 – 99.9%, wt., and the ratio N:P ₂ O ₅ :K ₂ O in mixtures (I) (15–25):(9–17):(9–17) and N:P ₂ O ₅ in mixtures (II) (11–45): (0.03–45)%, wt., respectively, it is also possible to introduce into the mixture one or more microelements, a strengthening additive: talc, or perlite, or carbon in an amount of 0.1 -0.3 wt. %, hydrophobizing additive - polymethylhydroxyloxane emulsion GKZh-94 in an amount of 0.04-0.4%, wt., followed by moistening the mixtures to a water content of 1.0-3.0%, wt., granulating in a standard industrial rotary molding granulator , sieving granules.. The static strength of granular fertilizer mixtures is 2.3–2.9 MPa without a binder and 3.1–3.9 MPa with a strengthening additive, hygroscopicity 1.0-2.4% [RF patent No. 2225382; publ. 03/10/2004].

The disadvantage of this method is the low content of the organic component and the use of a large amount of mineral additives, which will lead to the accumulation of pesticides and nitrates in the soil. Granules do not have high static strength values and can be destroyed during transportation and long-term storage.

The closest method for the same purpose to the claimed invention in terms of the combination of characteristics is a method for producing complex organic fertilizer. The basis of this fertilizer is peat compost with a liquid phase of fermented manure. Salts of copper, zinc, boron, as well as boric acid or other borates, urea, ammonium nitrate, sulfate and potassium chlorides are used as mineral supplements that participate in the synthesis of carbohydrates, vitamins and sugars. The multicomponent mixture is mixed in the required proportions, then the resulting substrate with a moisture content of 50–60% is sent to the pellet drum of a granulator-dryer (GDS), where granulation is carried out at a temperature of 50 ^o C. Afterwards, the finished granules are dried at 85–95 ^oC and sieved [RF patent No. 2337900; publ. 11/10/2008]. This method is adopted as a prototype.

The features of the prototype, which coincide with the essential features of the proposed method, are mixing the initial mass of the substrate with a binder solution; granulation by pelletizing; drying; sifting of granular product with separation of commercial fraction of 3.0–6.0 mm.

The disadvantage of the known method, adopted as a prototype, is the high cost of granular fertilizer containing a large amount of enriching additives and a low content of humic acids, while the high content of the mineral component of the fertilizer contributes to soil salinization, reducing its vegetative potential. The granules obtained by this method have low strength characteristics, which complicates the use of machine operators in the process of dispersing granular fertilizer, and also leads to destruction of the structure of the granules during transportation and storage. In particular, carrying out pelletizing at elevated temperatures contributes to an increase in current material costs when implementing the technology and an increase in the cost of the finished product.

The objective of the invention is to develop a method for granulating a highly effective organomineral fertilizer vermicompost, which makes it possible to obtain granules with high strength and rheological characteristics (static and dynamic strength of granules, abrasion, caking, hygroscopicity), reducing the cost of the resulting fertilizer.

The problem was solved due to the fact that in the known method of granulating organomineral fertilizer vermicompost, including mixing the initial mass of the substrate with a binding solution, granulation by the rolling method, drying and sifting of the granulated product with the separation of a commercial fraction of 3.0–6.0 mm, according to the invention When mixing the initial mixture of organomineral fertilizer vermicompost, an aqueous solution of sodium bicarbonate with a concentration of 20–30% and a content in the mixture of 6–8%, wt., is used as an inorganic binder; before granulation, the initial mixture is preformed in an extruder through a matrix with a die size of 7 mm , granulation is carried out at a temperature of 25–50 ^o C, drying is carried out at a temperature of 90–100 ^o C, when sieving the finished granulated product, part of the substandard fraction less than 3.0 mm is crushed and fed to the mixing stage as a retour with a content of 2–4%, wt.

Features of the proposed technical solution that are different from the prototype - when mixing the initial mixture of organomineral fertilizer vermicompost, an aqueous solution of sodium bicarbonate with a concentration of 20–30% and a content in the mixture of 6–8 wt% is used as an inorganic binder; before granulation by the rolling method, the initial mixture is preformed in an extruder through a matrix with a die size of 7 mm; granulation is carried out at a temperature of 25–50 ^o C; drying is carried out at a temperature of 90–100 ^o C; When sifting the finished granular product, part of the substandard fraction less than 3.0 mm is crushed and fed to the mixing stage as a retour containing 2–4%, wt.

Carrying out a preliminary stage of molding promotes the initial formation of granules, and also makes it possible to achieve a spherical shape of granules and a uniform granulometric composition during further pelletization. In particular, pre-molding helps to increase the yield of the commercial fraction of the granulated organomineral fertilizer vermicompost (3.0–6.0 mm) and the formation of a small amount of substandard fraction (less than 3.0 mm).

Carrying out the pre-forming stage in an extruder through a matrix with a die size of 7 mm makes it possible to obtain a pressate that is rolled more efficiently and subsequently, after drying the granulate, corresponds to the size of the established commercial fraction of 3-6 mm.

Part of the substandard fraction (less than 3.0 mm), after crushing, is introduced in the form of retur with a content of 2–4%, by weight, which eliminates the loss of valuable organomineral fertilizer vermicompost during granulation. Crushed particles of retur act as nuclei of granule formation and contribute to the formation of stronger granules with a heterogeneous structure, which increases the resistance of the granules to external mechanical influences. The yield of substandard fraction according to the stated method for producing organomineral fertilizer vermicompost does not exceed 5%.

The use of an inorganic binder is an aqueous solution of sodium bicarbonate with a concentration of 20–30% and a content in the mixture of 6–8%, wt. promotes the formation of microcrystalline compounds in the volume of granules, which leads to the formation of a reinforcing frame in the form of a large number of crystalline bridges from poorly soluble compounds.

The technical result achieved by implementing the claimed method is to increase the efficiency of granulation by the rolling method with the preliminary stage of molding the organomineral fertilizer vermicompost and to increase the strength characteristics of granules due to the action of an inorganic binding aqueous solution of sodium bicarbonate, which ensures the formation of crystals of sparingly soluble salts in the volume of the granule, strengthening the structure and introduction substandard crushed fraction as retour.

The static strength of the finished granules was measured using an IPG-1M device from the Federal State Unitary Enterprise "UNICHEM"; measurement of dynamic strength and abrasion was carried out in the PKPG-1 device, which is a 2-chamber drum with a drive; determination of hygroscopicity was carried out by the desiccator method, with exposure for 120 hours and atmospheric humidity of 98%; Determination of granulate caking was carried out using an ACAPEasy device from ATM-Systems using a method for determining the caking of mineral fertilizers developed at the Department of Chemistry of PNRPU.

EXAMPLES OF IMPLEMENTATION OF THE METHOD

Example 1

The method of granulating organomineral fertilizer vermicompost is carried out as follows. A soil-like mass of organomineral fertilizer with a moisture content of 55-60% is loaded into an extruder, the initial mixture is forced through a matrix with a die diameter of 7 mm and sent to a pellet drum with an inclination of 3 ^° and a rotation speed of 40 rpm, where the process of granulating the organomineral fertilizer vermicompost is carried out at a temperature 25 ^o C. Next, the granulate is sent for drying at 90 ^o C, after which sieving is carried out to isolate a commercial fraction of 3.0–5.0 mm. After measuring the strength characteristics, the static strength of the granules is 2.4 MPa, dynamic strength 91%, abrasion 9%, caking coefficient 21.6 kg/cm ² , hygroscopicity 1.1%.

Example 2

The method of granulating organic mineral fertilizer vermicompost is carried out similarly to example 1. The difference is that the drying process of the granulate is carried out at a temperature of 100 ^o C. In this case, the static strength of the resulting granules is 2.4 MPa, dynamic strength 92%, abrasion 8%, caking coefficient 20, 9 kg/ ^cm2 , hygroscopicity 1.3%.

Example 3

The method of granulating organomineral fertilizer vermicompost is carried out similarly to example 1. The difference is that the granulation process by rolling is carried out at a temperature of 50 ^o C. In this case, the static strength of the resulting granules is 2.3 MPa, dynamic strength 92%, abrasion 8%, caking coefficient 19 .8 kg/cm ² , hygroscopicity 1.2%.

Example 4

The method of granulating the organomineral fertilizer vermicompost is carried out similarly to example 1. The difference is that the granulation process by rolling is carried out at a temperature of 50 ^o C, and the drying process of the granulate is carried out at a temperature of 100 ^o C. In this case, the static strength of the resulting granules is 2.5 MPa, the dynamic strength strength 91%, abrasion 9%, caking coefficient 21.1 kg/ ^cm2 , hygroscopicity 1.3%.

Example 5

The method of granulating organomineral fertilizer vermicompost is carried out similarly to example 1. The difference is that after sieving, part of the substandard fraction less than 3 mm is crushed in a crusher and added as a retour to the original mixture before molding. The retur content is 2%, wt. In this case, the static strength of the resulting granules is 2.9 MPa, dynamic strength 94%, abrasion 6%, caking coefficient 18.7 kg/cm ² , hygroscopicity 0.9%.

Example 6

The method of granulating organomineral fertilizer vermicompost is carried out similarly to example 5. The difference is that after sieving, part of the substandard fraction less than 3 mm is crushed in a crusher and added as a retour to the original mixture before molding. The retur content is 3%, wt. In this case, the static strength of the resulting granules is 3.2 MPa, dynamic strength 94%, abrasion 6%, caking coefficient 18.1 kg/cm ² , hygroscopicity 1.0%.

Example 7

The method of granulating organomineral fertilizer vermicompost is carried out similarly to example 5. The difference is that after sieving, part of the substandard fraction less than 3 mm is crushed in a crusher and added as a retour to the original mixture before molding. The retur content is 4%, wt. At the same time, the static strength of the resulting granules is 2.9 MPa, dynamic strength 93%, abrasion 7%, caking coefficient 18.5 kg/cm ² , hygroscopicity 0.9%.

Example 8

The method of granulating organomineral fertilizer vermicompost is carried out similarly to example 5. The difference is that at the mixing stage, an inorganic binder is added to the initial mixture: a 20% aqueous solution of sodium bicarbonate, the content of which is 6%, wt. In this case, the static strength of the resulting granules is 4.8 MPa, dynamic strength 98%, abrasion 2%, caking coefficient 16.4 kg/cm ² , hygroscopicity 0.5%.

Example 9

The method of granulating the organomineral fertilizer vermicompost is carried out similarly to example 6. The difference is that at the mixing stage an inorganic binder is added to the initial mixture: a 25% aqueous solution of sodium bicarbonate, the content of which is 7%, wt., since with an increase in the retur content the granulometric composition changes and the moisture content of the fertilizer mixture decreases, which requires an increase in the binder content. In this case, the static strength of the resulting granules is 4.7 MPa, dynamic strength 97%, abrasion 3%, caking coefficient 16.9 kg/cm ² , hygroscopicity 0.6%.

Example 10

The method of granulating the organomineral fertilizer vermicompost is carried out similarly to example 7. The difference is that at the mixing stage, an inorganic binder is added to the initial mixture: a 30% aqueous solution of sodium bicarbonate, the content of which is 8%, wt., since with an increase in the retur content the granulometric composition changes and the moisture content of the fertilizer mixture decreases, which requires an increase in the binder content. In this case, the static strength of the resulting granules is 4.7 MPa, dynamic strength 98%, abrasion 2%, caking coefficient 16.6 kg/cm ² , hygroscopicity 0.6%.

Table

Strength characteristics of granular organomineral fertilizer vermicompost

Example No. 1 2 3 4 5 6 7 8 9 10 Prototype Static strength, MPa 2.4 2.4 2.3 2.5 2.9 3.2 2.9 4.8 4.7 4.7 2.0 Dynamic strength, % 91 92 92 91 94 94 93 98 97 98 88 Abrasion, % 9 8 8 9 6 6 7 2 3 2 12 Caking ability, kg/cm ² 21.6 20.9 19.8 21.1 18.7 18.1 18.5 16.4 16.9 16.6 34.1 Hygroscopicity,% 1.1 1.3 1.2 1.3 0.9 1.0 0.9 0.5 0.6 0.6 1.5

From the analysis of the data in the table it follows that the implementation of the method of granulating organomineral fertilizer vermicompost according to the claimed method in examples 1-10 makes it possible to achieve an improvement in the strength characteristics of the granules. The product obtained according to example 8 has the best quality characteristics, the static strength of which is 4.8 MPa, dynamic strength 98%, abrasion 2%, caking 16.4 kg/cm ² and hygroscopicity 0.5%, which will avoid problems with caking granulated vermicompost during transportation and long-term storage, and will also simplify the application of fertilizer over large areas when using machine operators.

In addition, the granular fertilizer obtained by the claimed method has a low cost, since inexpensive raw materials were selected for its production, energy-efficient parameters for producing granular fertilizer were determined, and low consumption of the binder was established.

Claims (1)

A method of granulating organomineral fertilizer vermicompost, including mixing the initial mass of the substrate with a binding solution, granulation by rolling, drying and sieving the granulated product with separation of a commercial fraction of 3.0-6.0 mm, characterized in that when mixing the initial mixture of organomineral fertilizer vermicompost An inorganic binder is used in an aqueous solution of sodium bicarbonate with a concentration of 20-30% and a content of 6-8 wt.% in the mixture; before granulation, the initial mixture is preformed in an extruder through a matrix with a die size of 7 mm; granulation is carried out at a temperature of 25-50°C , drying - at a temperature of 90-100°C, when sieving the finished granulated product, part of the substandard fraction less than 3.0 mm is crushed and fed to the mixing stage as a retour with a content of 2-4 wt.%.