RU2708985C1 - Method of producing natural organomineral fertilizer based on phosphoric flour - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to production of fertilizers and agro-preparations. Method involves drying of pre-screened peat with moisture content of 60 %, supplied from the first feed hopper, in a first drum drier to moisture content of 40 % in direct-flow mode with a drying agent obtained in the first gas heater. Crushing dried peat in first crusher, from which crushed fraction of 1 to 2 mm is fed to first screen for screening coarse fraction with subsequent transfer to first screw dispenser and through first unit flow ratio to reactor-mixer. Mixed peat is mixed with powdered sulfur obtained in the reactor-mixer and produced from the second feed hopper by means of a belt dispenser with fraction of 1 to 2 mm. Cavitational dispersion of sulfur and peat in water medium to homogeneous gel with fineness from 50 to 150 mcm in cavitator by means of screw pump. Glauconite is dried with humidity 15 %, fed from the third feed hopper, in a second drum dryer to moisture content of 3 %. Obtained homogeneous gel is mixed with finely dispersed phosphorite flour and glauconite in a two-shaft mixer in direct-flow mode with a drying agent obtained in the second gas heater. Grinding dried glauconite to 100 micron in a second crusher and screening its coarse fraction on a second screen with subsequent transmission by a second screw dispenser through a second flow ratio unit into a two-shaft mixer, where it is mixed with phosphorite flour, which is supplied from the fourth feed hopper by means of the third screw dispenser, and homogeneous gel. Granulation of the obtained mixture fed from a two-shaft mixer by a two-screw feeder into a granulator press; transfer of obtained granules with diameter of 5 mm and height of 5 mm by belt conveyor to drum counter-flow cooler for cooling to temperature of 30÷35 °C with external air with subsequent rolling and packing.

EFFECT: non-waste, environmentally safe method for obtaining a new kind of natural organomineral fertilizer of prolonged action based on phosphorite flour.

1 cl, 1 dwg

Description

The invention relates to a technology for the production of fertilizers and agricultural products and can be used to obtain a long-acting natural organic fertilizer based on phosphate rock (hereinafter - WMD).

From the existing level of technology there is known a method of producing activated phosphorite - a phosphate fertilizer of prolonged action, including grinding phosphate raw materials, anionic flotation, thickening the suspension, phosphoric acid treatment of phosphate concentrate, granulation and drying of the finished product. While the thickened suspension is pre-treated with sulfuric acid at a temperature of 30 ÷ 80 ° C. Gypsum is separated by flotation with cation exchange collectors (a mixture of high molecular weight primary and tertiary amines) [Pozin L.M., Baloven V.I., Treushenko N.N., Shuvalova N.K., Shokhin V.N., Bukseev V.V. , Tyulenev A.V., Rodina N.I., Orlov E.A., Belyakov V.A., Tatarsky A.E., Kulyukin A.N., Fomina B.A. A method of producing phosphorus fertilizer long-acting // Copyright certificate SU 893976 A1. IPC С05В 11/04, application No. 2917359 dated 04/29/1980. Published: 12/30/1981]. The disadvantages of this method of obtaining a phosphorus fertilizer of prolonged action include the complexity of the technological process of the chemical activation of phosphorites, the use of environmentally hazardous acid processing of phosphate raw materials, the presence of a large amount of production waste.

A known method of producing long-acting fertilizer, including grinding phosphate feedstock, anionic flotation, thickening the suspension, a two-stage treatment with sulfuric acid at pH 1.8 ÷ 2.4 and 4.1 ÷ 4.5 with the supply to the first stage of 50 ÷ 80% suspension and the introduction of the rest of the suspension to the second stage of processing, separation of gypsum, cationic flotation of an insoluble residue, treatment of phosphoric concentrate with phosphoric acid, granulation and drying of the product [Treushenko NN, Belov VN, Rumyantsev A.Yu., Belyakov VA , Bliznyuk T.V., Baloven V.I., Syrkin L.N., Shuvalova N.K., M Karov LP A method of producing phosphorus fertilizer long-acting // Copyright certificate SU 1116030 A1. IPC С05В 11/02, application No. 3536795 of 01/07/1983. Published: 09/30/1984]. The disadvantages of this method of producing long-acting fertilizer are the complexity and duration of the technological process of processing phosphate raw materials, the presence of a large amount of production waste, the use of environmentally hazardous acidic processing of phosphorites in the technological process.

A known method of producing phosphorus fertilizer by processing carbonate-containing natural raw materials with a mixture of a phosphorus-containing solution with ammonium sulfate in an amount of 100 ÷ 200% of stoichiometry on CO ₂ , and ammonium sulfate is 10 ÷ 20% by weight of the mixture, followed by processing of natural phosphate with an ammoniated phosphorus-containing solution, drying and granulation [Maksimenko N.F., Dolgov V.V., Saveliev V.N. Yakusheva R.I., Dmitrevsky B.A., Yarosh E.B., Golovina Z.M. A method of producing phosphorus fertilizer // Patent SU1581714 A1. IPC С05В 11/06. Application No. 4367626 from 01/22/1988, publ.: 07/30/1990]. The introduction of ammonium sulfate in the form of a solution makes it possible to intensify the process of activation and decarbonization due to the binding of calcium ions formed during the decomposition of calcium carbonate. Thus obtained fertilizer is positioned as a long-acting product. The main disadvantages of the proposed method are the high consumption of extraction phosphoric acid and ammonium sulfate, as well as environmental pollution by products of acid processing of phosphate raw materials.

A known method of producing phosphoric organic-mineral fertilizers of improved quality with a high content of assimilable phosphorus [Schuplyak AA, Sokolova IV, Yuryeva VI, Gladkov OA, Ivanova N.Ya., Ivanova R.G. ., Petrova L.A., Buzuleev A.B., Goncharov S.G. A method of producing phosphorus organic-mineral fertilizers // Patent RU 2108996 C1. IPC C05F 7/02, C05B 11/00, C05G 1/00. Application No. 97103006 dated 03/05/1997]. Fertilizer is obtained by mixing phosphorite flour or simple superphosphate with humic substances taken in an amount of 2 ÷ 9 wt. % followed by drying the mixture at 85 ÷ 105 ° C. As the humic substances, they take the product of the oxidative-hydrolytic degradation of lignosulfonates obtained by their oxidation with atmospheric oxygen in an alkaline medium at 150–200 ° C and a pressure of no more than 2.5 MPa. The main disadvantage of this method is the unsolved problem of activation of phosphate rock. In addition, the inclusion of humic substances in the composition of phosphate rock significantly increases the cost of the resulting fertilizer.

Closest to the claimed technical solution according to the technical essence and the technical result achieved is a method for producing prolonged-action fertilizers based on phosphate rock, sulfur, urea phosphate and humates [Budkov V.A., Pukhovsky A.V., Sychev V.G. The method of obtaining complex fertilizers prolonged action // Patent RU 2443663 C1. IPC С05В 13/02, C05G 1/00. Application No. 20102929268/13 of 07.15.2010, published: 02.27.2012 in Bull. No. 6]. The method includes mixing phosphorite flour with dispersed elemental sulfur in a weight ratio (phosphorite flour: dispersed elemental sulfur) from 6: 1 to 4: 1 and urea phosphate in a weight ratio of it to phosphorite flour from 1: 0.8 to 1: 8.5 followed by granulation of the mixture by pressing. Phosphorite flour before mixing with other components is treated with humate in an amount of 0.1 ÷ 1.0 weight. % The described method is the combination of essential features closest to the claimed invention, therefore, it is adopted as a prototype of the claimed invention. The disadvantages of this method are the high cost and scarcity of urea phosphate included in the fertilizer, the high cost of humates and the unsolved problem of eliminating excess acidity, which, due to the high sulfur and urea phosphate content in the fertilizer, will inevitably occur when this fertilizer is applied to the soil. Due to the pronounced acidifying effect, the proposed fertilizer can be used only on neutral and alkaline soils. Meanwhile, a third of the arable land of the Russian Federation is characterized by increased acidity, and the tendency to acidification of soils is becoming dangerous.

The technical result of the invention is the development of a non-waste, environmentally friendly method for producing a new type of natural organic fertilizer of prolonged action based on phosphate rock. Fertilizer must be compatible with other organic and mineral fertilizers and suitable for use on any type of soil.

A new type of fertilizer is obtained due to the optimal selection of WMD components, including phosphorite flour, sulfur, glauconite (or quartz-glauconite sand), water and peat containing a complex of humic substances providing a synergistic effect when fertilizing the soil, using the natural microbiological potential of soil systems and application of non-waste technology for the production of granular forms of fertilizer.

The technical result is achieved by the fact that peat screened from roots and inclusions with a moisture content of 60% is fed to a feed hopper (1) in front of a drum dryer (2), from which it is uniformly fed in a direct-flow mode with a drying agent obtained in a gas heater, to dry to moisture 40% Dried peat enters the crusher (3), from which the crushed fraction 1 ÷ 2 mm is fed to a screen (4) for screening the commercial fraction on a screw batcher (5) for feeding to the cavitation processing unit. At the same time, sulfur powder with a fraction of 1 ÷ 2 mm is supplied to the cavitation treatment unit. From the sulfur feed hopper (6), the sulfur powder is fed with a tape dispenser (7) to the reactor (8) at the same time as crushed peat is fed through the flow ratio unit. Water is supplied to the mixer reactor to prepare the initial suspension (gel), which is supplied to the cavitator (10) by a screw pump (9). The cavitator feeds the obtained gel back to the mixer reactor to saturate the marketable gel to the required solids content and the required grinding fineness in the region of 50-150 microns. The gel is fed as a binder into a twin-shaft mixer, where phosphorite flour (hereinafter referred to as fosmuk) and quartz-glauconite sand (or glauconite) are fed. Quartz-glauconite sand with a moisture content of 15% (or glauconite) is fed into the feed hopper (11). In a tumble dryer (12) in direct-flow mode with a drying agent obtained in a gas heater, quartz-glauconite sand (or glauconite) is dried to a moisture content of 3%. Dried quartz-glauconite sand (or glauconite) is fed to a crusher (13) for grinding to 100 microns and then to a screen (14) for screening a large fraction. The crushed dried quartz-glauconite sand (or glauconite) with a screw batcher (15) is fed through the flow-to-phosphor ratio block, which is fed from the feed hopper (16) with a screw batcher (17) into a twin-shaft mixer (18). A uniform moistened mixture of components is fed by a twin-screw feeder (19) to the pellet mill (20). Pellets with a diameter of 5 mm and a height of 5 mm are fed by a conveyor belt (21) to a countercurrent drum refrigerator (22) in which the granules are cooled to 30 ÷ 35 ° C with outside air, additionally rolled and fed into bags or soft containers (big-bag) after the refrigerator. on the scales (23) for filling.

The composition and production technology of WMD comply with the principles of Green Chemistry. Highly decomposed peat, phosphorite flour, glauconite concentrate with glauconite content of 95 ± 5% (hereinafter referred to as glauconite) or quartz-glauconite sand with glauconite content of at least 45 mass%, ground sulfur are used as raw materials for the production of WMD. Fosmuka (a product of enrichment of grinding of natural phosphorites), sulfur, glauconite (or quartz-glauconite sand) and peat are non-toxic natural materials widely used in agriculture, fertilizer technology and agricultural products. All raw materials used for the production of WMD are of low cost and affordability. The Russian Federation has huge reserves of all types of raw materials needed to produce the corresponding WMD.

The component composition of the fertilizer was determined so that the following technological and agrochemical problems were successfully solved:

- the necessary bioavailability of phosphorus is provided when fertilizing the soil due to the conversion of tricalcium phosphate to mono and dicalcium phosphates;

- a prolonged effect of the action of fertilizer is provided, due to the gradual transition of phosphorus into a soluble form under the action of products of microbiological oxidation of sulfur;

- provided the possibility of obtaining fertilizer in granular form;

- increased agrochemical effectiveness of fertilizer (compared with the effectiveness of phosphate rock);

- minimized the effect of the negative impact of WMD on soils and the environment.

The functional load and mechanisms of interaction of the individual components of WMD with each other and with soil systems can be represented as follows:

- phosphorite flour is a cheap, safe, affordable, but sparingly soluble source of phosphorus;

- sulfur provides the activation of poorly soluble fertilizer phosphates directly in the soil. The gradual (prolonged) activation of phosphates will occur due to sulfuric acid formed as a result of microbiological oxidation of sulfur in the upper horizons of the soil (aerobic conditions). Under the influence of sulfuric acid, sparingly soluble calcium phosphates contained in phosphorite flour will turn into more soluble hydrophosphates available for plants:

Ca ₃ (PO ₄ ) ₂ + 2 × H ₂ SO ₄ + n × H ₂ O = Ca (H ₂ PO ₄ ) ₂ × H ₂ O + 2 × (CaSO ₄ × 2H ₂ O)

The amount of sulfur introduced into the composition of WMD is calculated in accordance with the stoichiometry of the conversion of tricalcium phosphate to dicalcium phosphate under the influence of sulfuric acid. Sulfate ions generated as a result of sulfur oxidation will make up for the sulfur deficiency in soils (which is of great practical importance, since at present up to 80% of the arable land of the Russian Federation is characterized by a low sulfur content, which leads to a decrease in yield and a decrease in protein accumulation in crop production ), in addition, elemental sulfur will exhibit fungicidal activity, limiting the development of root rot, which poses a serious danger to modern crop production;

- peat in the fertilizer is a source of humic (humic and fulvic) acids. Humic acids promote the binding of one and a half oxides (compounds Fe ³⁺ and Al ³⁺ ) contained in soil and phosphorite flour to strong chelate complexes, thus preventing the formation of sparingly soluble iron (III) phosphates and aluminum. Due to humic acids, biostimulating and adaptogenic effects are provided that contribute to better plant development. Peat humates are involved in regulating the acidity of the soil solution, preventing a decrease in pH under the influence of sulfur oxidation products. In addition, the use of peat makes it possible to optimize the granulation process and obtain sufficiently strong WMD granules;

- the inclusion of glauconite (or quartz-glauconite sand) in the fertilizer prevents the risk of increasing the acidity of the soil solution due to sulfur oxidation products. Glauconite will bind one-and-a-half oxides, thus preventing the transition of phosphates to slightly soluble and inaccessible to plants forms, and the immobilization of one-and-a-half oxides by glauconite will have a longer duration than the immobilization of one-and-a-half oxides by humic acids. The rich mineral composition and ion-exchange properties of glauconite will optimize the mineral nutrition of plants and stimulate the development of beneficial soil microflora. In addition, due to its high water absorption capacity, glauconite will play the role of a water binding agent, facilitating the granulation process of WMD.

The classical scheme for the preparation of water-soluble phosphorus fertilizer (double superphosphate) consists of the stage of converting sparingly soluble tricalcium phosphate into soluble mono- and dicalcium phosphates by treating the phosphate feed with extraction phosphoric acid, which is obtained by treating tricalcium phosphate with sulfuric acid, followed by separation of phosphogypsum. Sulfuric acid is obtained by oxidation of sulfur, followed by the interaction of sulfur oxide with water. Appropriate technology is very expensive. The production of superphosphate by the appropriate technology is associated with the formation of a large amount of waste and environmental pollution by products of acidic processing of phosphate raw materials.

The claimed technology for producing WMD differs from the classical technology in that the stage of formation of sulfuric acid and the stage of formation of mono- and dicalcium phosphates will be implemented not in chemical apparatuses, but directly in the soil with the participation of microorganisms using soil moisture and atmospheric oxygen (the soil plays a role in this regard natural bioreactor). The addition of peat containing a complex of humic and other substances necessary for the vital activity of soil microflora promotes the activation of microbiological processes of sulfur oxidation. Sulfuric acid formed during the oxidation of sulfur will facilitate the conversion of insoluble phosphates to soluble hydrophosphates. Activation of phosphorites directly in the soil helps to save capital costs, dramatically reduces the cost of new fertilizer, and reduces the amount of production waste to zero. Moreover, the technology of granulating WMD is simplified in terms of using a press granulator, turbopaste granulator or molding granulator without the use of a traditional granulator-dryer, in which, in addition to the drying and granulation stage, the transition of tricalcium phosphate to mono- and dicalcium phosphates ends. The flow chart of the production of the corresponding WMD is shown in the Figure.

100 kg of WMD will contain (kg):

phosphorite flour - 70 ÷ 85;

quartz-glauconite sand (with the content of glauconite 45 ÷ 50 wt.%) - 8 ÷ 12 or glauconite - 4 ÷ 6;

powder sulfur (ground) - 5 ÷ 10;

peat of a high degree of decomposition - 5 ÷ 10 (including humic acids - 7 ÷ 8% by weight of peat).

The main active substances of WMD will be phosphorus (at least 16% in terms of P ₂ O ₅ ) and sulfur (at least 5% in terms of S). The ratio of phosphorus and sulfur in the fertilizer can be considered optimal, since most crops require less sulfur than phosphorus.

Properties of the finished fertilizer

The finished form of fertilizer is a non-hygroscopic granular product with a granule size of about 3 mm. The color of the granules is dark gray. The granules can withstand a load of at least 1.2 kg per granule, which allows them to be transported in bags or soft containers. During storage, the granules do not cake. When introduced into the soil under the influence of soil moisture, the granules swell and crumble, which provides the necessary rate of microbiological processes for the oxidation of finely dispersed sulfur and activation of finely dispersed phosphorite flour. WMD is compatible with other forms of mineral and organic fertilizers, plant protection products, growth regulators and can be used on any type of soil and under any crop.

The appropriate fertilizer is intended for use on all types of soils and for various crops. It can be of the greatest value for growing crops that require sulfur content (rapeseed, turnip, radish, garlic, onions, cabbage, broccoli, mustard, as well as beets, corn, flax, cotton, tobacco, soy, peas, alfalfa, clover and other).

Tests of the obtained WMD samples showed that this fertilizer is not inferior to simple superphosphate in efficiency, while the cost of WMD is more than 2 times lower than the cost of superphosphate [Syrchina N.V., Bogatyreva N.N., Terentyev Yu.N., Kozhevnikova A.S. Activating additives to increase the solubility of phosphate rock in soils // Transformation of ecosystems under the influence of natural and anthropogenic factors: Materials of the international scientific conference, (Kirov, April 16-18, 2019). - Kirov: Vyatka State University, 2019.S. 227-232; Martynov M.V., Malysheva A.V., Potapova I.A., Syrchina N.V. Evaluation of activated phosphate rock of various deposits by biotesting // Ecology of the native land: problems and solutions: Materials of the IV All-Russian Scientific and Practical Conference with international participation (Kirov, April 16-18, 2019). - Kirov: Vyatka State University, 2019. S. 114 - 118].

Unlike the prototype, the proposed technical solution has the following advantages:

- the WMD granulation technology proposed in this technical solution is simpler in terms of using a press granulator, turbopaste granulator or molding granulator without the use of a traditional granulator dryer;

- the introduction of WMD into the soil does not lead to a decrease in the pH of the soil solution;

- the inclusion of glauconite (or quartz-glauconite sand) in the composition of OMU can significantly reduce the risk of phosphorus becoming inaccessible to plants due to the formation of sparingly soluble iron (III) phosphates and aluminum, which significantly increases the utilization rate of phosphorus; glauconite helps to improve the technological and agrochemical characteristics of the fertilizer (facilitates granulation and increases the strength of granules, improves the mineral nutrition of plants, reduces the risk of acidification of the soil);

- WMD is suitable for use on any type of soil;

- WMD production is non-waste and fully complies with the principles of Green Chemistry.

Claims (2)

1. A method of producing a natural organomineral fertilizer based on phosphorite flour containing phosphorite flour, sulfur powder, glauconite, water and peat, includes drying pre-screened peat with a moisture content of 60% from the first feed hopper in the first drum dryer to a moisture content of 40% in a direct-flow mode with a drying agent obtained in the first gas heater; grinding dried peat in the first crusher, from which the crushed fraction from 1 to 2 mm is fed to the first screen for screening a large fraction, followed by transfer to the first screw dispenser and through the first flow ratio unit to the reactor-mixer; mixing in the reactor-mixer of ground peat with sulfur powder obtained from the second feed hopper by means of a tape dispenser with a fraction of 1 to 2 mm; cavitation dispersion of sulfur and peat in an aqueous medium to a state of a uniform gel with a fineness of 50 to 150 microns in a cavitator using a screw pump; drying glauconite with a moisture content of 15% supplied from the third feed hopper in a second drum dryer to a moisture content of 3%; mixing the obtained homogeneous gel with finely divided phosphorite flour and glauconite in a twin-shaft mixer in a direct-flow mode with a drying agent obtained in the second gas heater; grinding dried glauconite up to 100 microns in a second crusher and screening its coarse fraction in a second screen, followed by transferring the second screw batcher through the second flow ratio block to a twin-shaft mixer, where it is mixed with phosphorite flour, which comes from the fourth feed hopper through the third screw batcher, and homogeneous gel; granulating the resulting mixture fed from a twin-shaft mixer with a twin-screw feeder into a press granulator; transferring the obtained granules with a diameter of 5 mm and a height of 5 mm by a conveyor belt to a countercurrent drum cooler for cooling with outside air to a temperature of 30–35 ° C, followed by rolling and packing. 2. The method according to p. 1, characterized in that instead of glauconite can be used quartz-glauconite sand.

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