Method of obtaining liquid complex fertilisers. RU patent 2510626.
 Method of producing fertiliser and co2 / 2449949Invention can be used in chemical industry and agriculture. Carbon dioxide-containing gas reacts with a base to form a carbonate. The base is selected from a group comprising calcium oxide, calcium hydroxide, a stream containing calcium oxide, a stream containing calcium hydroxide and a combination thereof. The obtained product reacts with a reactant selected from a group comprising nitric acid, phosphoric acid, a salt thereof and a mixture thereof, to form CO2 and an intermediate product. At least a portion of the CO2 is separated from the intermediate product and a condensed and relatively concentrated stream is formed therefrom. The intermediate product reacts with ammonia to form fertiliser selected from a group comprising ammonium nitrate, ammonium phosphate or a combination thereof. At least a portion of the base forming said intermediate product is regenerated. At least a portion of said fertiliser is separated from the mixture formed at the previous step. |
| Dissoluble and dissolving loose compositions of solid fertilisers and method of their production / 2429213 Composition contains from 35 wt % to 41 wt % of phosphoric acid, from 59 wt % to 65 wt % of monopotassium phosphate and from 0.1 to 0.6 wt % of water. The method includes mixing of phosphoric acid, monopotassium phosphate and water, heating up to 65-90°C, evaporation of the produced solution in vacuum at the temperature of 10-120°C to produce a solid uniform material, cooling of material. Fertiliser solutions remain transparent even with content of calcium nitrate or magnesium nitrate, or potassium phosphate with salts of such metals as Zn, Fe, Cu, Mn, Mo, etc., and may be stored without loss of the specified properties. |
| Method of producing ammophos / 2420453 Invention relates to technology of producing mineral fertiliser. Low-grade phosphate raw material - Karatau phosphorites are decomposed by a mixture of phosphoric and nitric acid. Product acid is extracted from the reaction mass, concentrated, purified from impurities, ammoniated to obtain phosphate pulp, granulated and dried. In the concentrated acid, content of P2O5 is kept in the range of 39-44%, content of SO3 - 2.5 - 4 %, residual content of solid impurities in the clarified concentrated acid is kept at 0.4-2 wt %, and molar ratio NH3 : H3PO4 is kept in the range of 1.0-1.20. Control of the yield of the required type of ammophos on content of nutrients and ratio thereof is carried out by adding sulphuric acid to the process in amount of 90-225 kg mng per 1 t of P2O5 in the product. Sulphuric acid is added to the absorption system in amount of 50-75 kg mng per 1 t of P2O5, and the remaining amount is added to phosphoric acid before ammoniation. |
 Method of obtaining nitrophosphate products with high nitrogen content / 2412139Invention relates to a method of producing granular, non-oxidising and non-explosive nitrophosphate and/or nitrogen-phosphate-potassium products with high nitrogen content. The method involves obtaining a melt/suspension containing ammonium nitrate and monoammonium phosphate. The melt/suspension contains less than 2 wt % water. Before granulating the melt when producing nitrogen-phosphate fertilisers with high nitrogen content, the melt is mixed with 0.1-10 wt % water-binding agent and solid ammonium sulphate in an amount which provides overall composition of the melt where nitrogen content is greater than or equal to 25 wt % and ammonium nitrate content is less than 70 wt %. When producing nitrogen-phosphate-potassium fertilisers with high nitrogen content, the melt is mixed with 0.1-10 wt % water-binding agent, solid ammonium sulphate and at least one solid potassium salt in an amount which provides overall composition of the melt where nitrogen content is greater than or equal to 25 wt % and ammonium nitrate content is less than 70 wt %. The melt is granulated to form solid particles. The prilled particles contain 25-29 wt % nitrogen, and content of nitrate nitrogen is less than 12.2 wt %, preferably less than 11.4 wt %. Content of water-soluble phosphorus in the granules is greater than or equal 45 wt %, while that of citrate-soluble phosphorus is greater than or equal to 95 wt %. |
| Method of producing non-chlorine npk compound fertilisers / 2409536 Method involves neutralisation of an acidic phosphorus-containing solution with an alkaline potassium-containing reagent at the first step and then adding sulphuric acid and neutralisation with ammonia at the second step, granulation and drying the end product. Nitric acid and ammonium nitrate are added when neutralising the acidic phosphorus-containing solution at the first step. The alkaline potassium-containing reagent and ammonium nitrate are added to the acidic phosphorus-containing solution while maintaining the required ratio of nutrient components in the end product. Nitric acid is added in an amount which provides pH 2-5 at the first step. The pH value at the second neutralisation step is kept at 4-6. The acidic phosphorus-containing solution used is phosphoric acid or a nitric-phosphate solution which is a product of decomposition of phosphate material with nitric acid with subsequent extraction of potassium in form of a tetrahydrate of calcium nitrate. |
| Method of obtaining nitrogen-phosphate compound fertiliser / 2407720 Method involves ammonation of a mixture of a phosphorus-containing component with ammonium nitrate, evaporation and granulation of the obtained mixture followed by treatment of the granules with an anti-caking substance. The phosphorus-containing component is a clear ammonium phosphate solution with concentration of 16-30% in terms of P2O5, obtained through ammonation of wet-process phosphoric acid to pH 2.2-3.0 and then separation of the precipitate. |
 Diammonium phosphate synthesis method / 2406713Invention relates to a method for synthesis of diammonium phosphate which has antiseptic properties. The method involves mixing phosphoric acid and spent sulphuric acid from petrochemical production in amount of 25-30 kg per ton of phosphoric acid and industrial sulphuric acid until attaining 6.5-7.0 % SO3 content in the mixture, step by step neutralisation of ammonia with the mixture of acids until molar ratio NH3/H3PO4 = 1.4, and then to 1.75, granulation, drying the product and subsequent cleaning of exhaust gases in two steps, at the first step of which ammonium phosphate pulp with molar ratio NH3/H3PO4 = 0.4 -0.5 is fed, and at the second step - a mixture of acids and an additional antifoaming agent PG-3 in amount of 0.5-2 g per ton of the end product. |
| Method of obtaining nitrogen-phosphate compound fertiliser / 2404149 Method involves ammonation of a mixture of a phosphorus-containing component with ammonium nitrate, evaporation and granulation of the obtained mixture followed by treatment of the granules with an anti-caking substance. The phosphorus-containing component is a clear ammonium phosphate solution with concentration of 16-30% in terms of P2O5, obtained through ammonation of wet-process phosphoric acid to pH 2.2-3.0 and then separation of the precipitate. |
 Diammonium phosphate synthesis method / 2397970Invention relates to a method for synthesis of diammonium phosphate which has antiseptic properties. The method involves mixing phosphoric acid and spent sulphuric acid from petrochemical production in amount of 25-30 kg per 1 ton of phosphoric acid and industrial sulphuric acid until attaining 6.5-7.0% SO3 content in the mixture, step by step neutralisation of ammonia with the mixture of acids until molar ratio NH3/H3PO4 = 1.4, and then 1.75, granulation, drying the product and subsequent cleaning of exhaust gases in two steps, at the first step of which an ammonium phosphate pulp with molar ratio NH3/H3PO4 = 0.4-0.5 is fed, and at the second step - the mixture of acids and an additional antifoaming agent PG-3 in amount of 0.5-2 g per 1 ton of the end product. |
 Method of producing granular ammonium phosphates / 2371424Invention relates to the method of producing granular ammonium phosphates with varying chemical composition, widely used in agriculture as fertiliser. The method of producing granular ammonium phosphates involves neutralising phosphoric acid with ammonia in a gas-liquid stream with subsequent granulating and drying the product. In this method neutralisation is done at varying flow rate of the gas-liquid stream, where acceleration is 1.1 to 2.2 m/s2, decceleration - 0.2 to 0.4 m/s2, and the ratio of the maximum to the minimum speed varies in the range 2.5 to 4. Use of acid with 42 to 48% P2O5 concentration during neutralisation is preferred. |
 Method of manufacturing granulated mineral fertilizer containing nitrogen and phosphorus; and granulated mineral fertilizer / 2253639Method of manufacturing complex granulated mineral fertilizer consists in mixing ammonium nitrate and monoammonium phosphate-containing phosphate additive. The latter is granulated mineral double fertilizer simultaneously containing ammonium nitrate, monoammonium phosphate, and calcium phosphates at total content of digestible phosphorus 13÷21% (calculated as P2O5). Additive is introduced by way of melting it followed by admixing resulting melt to molten ammonium nitrate. Phosphate additive utilizes nitroammophosphate at weight ratio N:P2O5 equal to 23:21 or 26:13 and phosphate additive melt is preliminarily completely or partly separated from infusible solid phase, after which phosphate additive is introduced in amount 2-6% (as P2O5) of the weight of final product. Granulated mineral fertilizer contains ammonium nitrate and monoammonium phosphate with total content of digestible P2O5 within a range of 2÷6%, in which case 0.4÷28.6% of P2O5 is present in the form of dicalcium phosphate. |
| Ammonium phosphate production process / 2255041 Invention relates to production of ammonium phosphates, notably ammophos, widely used as mineral fertilizers. Process involves neutralization of phosphoric acid with ammonia at elevated pressure, stirring of resulting mixture in static mixer, and subsequent granulation and drying of product. According to invention, neutralization is carried out in two steps: in the first step, 80-85% H3PO4 of its total amount is added and process is carried out at gauge pressure 3.5-8 atm and, in the second step, the rest of acid is added and pressure is lowered to pressure 1.5-3.0 atm. Stirring is effected simultaneously with ultrasonic treatment of the mixture with pulse power from 100 to 1000 W and, before granulation, pressure is lowered by 0.5-0.8 atm relative to pressure of the second neutralization step. Ultrasonic treatment can likewise be employed in the first neutralization step. |
| Method for preparing monoammonium phosphate / 2259941 Invention relates to a method for preparing monoammonium phosphate used broadly as a mineral fertilizer. Method involves decomposition of phosphate with a mixture of phosphoric and sulfuric acid, separation of reaction mass with isolation of the production acid, its purifying from impurities, concentrating, ammoniation to obtain phosphate pulp and the following procedures of granulation and drying. The separated production acid is concentrated and then subjected for purification from impurities and ammoniated maintaining the content of P2O5 in the concentrated acid at these stages in the range 52-56%, the content of SO3 at the range 1.5-3.2%, the residual content of solid impurities in the cleared concentrated acid 0.2-0.6% by mass, and the mole ratio NH3 : H3PO4 in the range 1.01-1.16. Regulation of the yield for required sort of monoammonium phosphate by the content of main nutrient substances and the ratio is carried out by change of the SO3 content in dilute phosphoric acid and by change of the mole ratio NH3 : H3PO4 in the ammoniation process. Invention provides enhancing content of total sum of nutrient substances in the fertilizer and enhancing strength index of granules and their homogeneity. |
| Method of production of diammonium phosphate / 2261221 The invention is pertaining to production of ammonium phosphates, in particular, diammonium phosphate widely used in agriculture as mineral fertilizers. The method includes neutralization of phosphoric acid by ammonia at an increased pressure, a stirring action of the produced mixture in a static mixer with its subsequent granulation and drying of the product. Neutralization is conducted in two stages: on the first of which feed 8 - 85 % of ammonia from total amount and the process is conducted under the pressure of 3.5 - 8.0 atm, and on the second stage feed the remained amount of ammonia and reduce pressure to 1.5 - 3.0 atm. At that the stirring action is carried on simultaneously with a treatment of the mixture with ultrasound with a pulse power from 100 up to 1000 W. Before granulation additionally reduce the pressure by 0.5 - 0.8 atm as compared with the pressure of the second stage of neutralization. Ultrasonic treatment additionally conduct and on the first stage of neutralization. The technical result is production of a homogenous product of improved quality, decreased power inputs and losses of ammonia in the general process. |
| Method of production of monopotassium phosphate / 2261222 The invention is pertaining to production of monopotassium phosphate used as fertilizers, food additives, and also in medicine and microbiology. The method provides for neutralization of phosphoric acid by potassium carbonate up to pH not above 4.5 at the heightened temperature, separation of the produced admixture by filtration with the subsequent crystallization and separation of the finished product at cooling. Potassium carbonate take in the form of a water solution with the concentration necessary for production in the neutralized mixture of 23-30 % monopotassium phosphate. The neutralization process is conducted at the temperature of 70-78°C, and the mother liquor after separation of the finished product at the stage of a crystallization return into the process on the stage of dissolution of potassium carbonate. Reaction of the neutralization conduct up to pH = 3.8-4.5. The technical result is an increase of output of the finished product up to 95-97 % and creation of the wasteless production due to utilization of a mother liquor in the process. |
| Method of producing ammophos / 2263091 Method comprises neutralizing phosphate acid by ammonium, granulating, drying the product in the drum granulator-dryer, classifying granules, and cooling the finished product in a fluidized bed, with supplying ammonium for neutralizing in amount that exceeds the value required for the product by 0.2-0.5% (on conversion to nitrogen). The finished product is cooled under the rarefication of 300-600 mm Hg, and the fluidized bed is blown by the atmospheric air produced in the rarefication. |
| Methods for obtaining fertilizers based upon ammonium phosphate at controlled release of nutrients / 2263093 The method suggested deals with supplementing materials to aqueous viscous paste or powder of ammonium phosphate to control the release of nutrients chosen out of the following lest: montmorillonite, granulated montmorillonite, lignin containing alkaline lignin and lignosulfonate, or acidified zeolite, acidified montmorillonite, acidified granulated montmorillonite, acidified lignin containing acidified alkaline lignin and acidified lignosulfonate. Content of materials that provide controlled release of nutrients in fertilizer corresponds to 3-35% against the weight (based upon dry weight of ammonium phosphate powder), and content of water after condensation corresponds to 25-35% against the weight (based upon dry weight of ammonium phosphate viscous paste). It is possible to acidify the mixture of ammonium phosphate and materials that provide controlled release of nutrients before condensation with sulfuric acid. Application of the suggested fertilizer increases the efficiency in digesting nutrients by plants, activity period of the fertilizer is more prolonged and its cost has been decreased. |
| Method for production of complex nitrogen-phosphorous fertilizer / 2266272 Invention relates to method for production of double NP-fertilizer containing 3-7 mass % of P2O5 from concentrated ammonium nitrate solution and extractive phosphoric acid solution. Starting phosphoric acid (52-54 %) is diluted with weak ammonium nitrate solution, diluted solution is additionally treated with ammonium nitrate to produce NH4NO3:P2O5 ratio in ammoniated solution not less than 3:1, wherein ammoniating is carried out simultaneously with auxiliary treatment or thereafter. Ammoniated solution is boiled down to produce residual water content of 5-20 mass % and mixed with concentrated ammonium nitrate solution. Then obtained solution is finally neutralized with ammonia, boiled down and grained. Phosphorous content in ammoniated solution is maintained preferably from 4 to 10 mass % calculated as P2O5, and as ammonium nitrate in auxiliary treatment of diluted solution preferably concentrated ammonium nitrate solution obtained by nitric acid neutralization with ammonia or 40-50 % solution obtained by conversion of calcium nitrate with ammonium carbonate is used. |
| Method for preparing granulated ammophos / 2286319 Invention relates to a method for preparing granulated ammophos. Method involves neutralization of phosphoric acid with ammonia, granulation of product by pulp raising dust on the recycle particles in the presence of acid agent added in the amount necessary for providing pH value of granulated mixture 3.5-4.8 and simultaneous drying the ready product. Acid neutralizing agent is applied preliminary on the recycle granules surface at temperature 70-90°C wherein the recycle is taken with granules strength 3-8 MPa. As acid agent method involves using phosphoric and/or sulfuric acids. Invention provides increasing yield of commercial fraction 2-5 mm up to 80-90%. |
 Method for production of complex fertilizers / 2286320Invention relates to method for production of complex fertilizers by decomposition of apatite concentrate with nitric acid by using low-grade phosphate raw materials are used. Claimed method includes decomposition of apatite concentrate with nitric acid, calcium nitrate isolation from nitrophosphate extract, crystallization followed by conversion thereof in ammonium nitrate; neutralization of separated nitrate-phosphate solution with ammonia, vaporization, blending of evaporated pulp with low-grade phosphate raw materials, ammonium nitrate and potassium salt; granulation and drying of finished product. According to this invention low-grade phosphate raw materials are preliminary treated with conversion ammonium nitrate solution at S:L = 1:1-3 to produce in slurry ratio of P2O5digestible:P2O5total = 35-45 %. PH of conversion solution is maintained preferably either 0.3-1.5 or 7.5-9, with the proviso, that when pH is 0.5-1.5 ratio of apatite and low-grade phosphate raw materials calculated as P2O5 is (1.5-3):1; and when pH is 7.5-9 abovementioned ratio is (4.2-5):1. |
FIELD: chemistry.
SUBSTANCE: invention relates to agriculture. Method of obtaining liquid complex fertilisers includes neutralisation of extraction phosphoric acid with nitrogen-containing reagent, separation of sediment of non-soluble admixtures from obtained solution, introduction of solution of salts of microelements in presence of complex-forming agent. As nitrogen-containing reagent used is carbamide in form of water solution, taken in mole ratio carbamide: H3PO4, equal (1.5-2.5):1; process of neutralisation is carried out at temperature 95-99°C and density of reaction mass 1.22-1.28 g/cm3 until value of pH of reaction medium reaches 6.5-7.2 in presence of calcium-containing agent, taken in mole ratio calcium:fluorine, equal 1:2, and separation of sediment of non-soluble admixtures is carried out when pH of reaction medium reaches 5.0-5.9.
EFFECT: invention makes it possible to obtain liquid complex fertiliser with balanced composition and low content of admixtures of fluorine and sesquioxides.
2 cl, 2 tbl, 2 ex
The invention relates to the production of liquid complex fertilizers containing nitrogen, phosphorus and trace elements, used in agriculture for growing products in both open and closed ground.
A method of obtaining liquid complex fertilizers [A.S. USSR №298575, CL CV 11/00, publ. 16.03.1971] neutralization of phosphoric acid, ammonia water while maintaining the ratio of the liquid and solid phases of the reaction mass from 10:1 to 24:1, followed by the mixing reaction mass with solid mineral components. As solid mineral components use the urea and chloride potassium. The method allows to obtain complex nitrogen-phosphate and isotopically liquid fertilizers without adding suspenziya additives.
The disadvantage of this method is the production of the liquid fertilizers in the form of suspension and ballast containing impurities, and also unsuitable for long storage.
A method of obtaining transparent liquid complex fertilizers [RF patent №2167133, CL SV 7/00, 05D 1/00, C05G 1/00, publ. 20.05.2001] by introducing wet-process phosphoric acid (EPA) sekvestriruyut agent in the amount of up to 5.0% of the mass of liquid fertilizers and neutralization of acid potassium reagent and the subsequent introduction of additional macro - and microelements in the form of complexions. As sekvestriruyut agent uses organic compound selected from a group of agents, as oxyethylenediphosphonic acid OEDPK, nitriltrimetilenfosfonovaya acid NTF, diethylenetriaminepentaacetic acid, DTPA, etilendiamindioksimom acid ADAC, ethylenediaminetetraacetic acid ATL. To the obtained solution of potassium phosphate enter urea or ammonium nitrate as nitrogen-containing component. Introduction of complexing agents provides translation of ballast impurities extraction phosphoric acid, as Queen-size iron and aluminum oxides in soluble form.
The disadvantage of this method is considerable consumption of complexing agents and low quality fertilizer because of the content of ballast substances.
A method of obtaining liquid complex fertilizers "Segeda" [A.S. USSR №1549941, CL C05G 1/06, publ. 29.02. 1988], which includes neutralization of phosphoric acid nitrogen-containing reagent with obtaining solution of ammonium phosphate, mixture of water solutions of ammonium phosphate, potassium nitrate, ammonium nitrate and introduction of salts and microelements in the presence of complexing agents. As a nitrogen-containing reagent is used ammonia water; salts, microelements - nitrate or sulphate zinc, copper, manganese, cobalt, magnesium, ammonium molybdate and boric acid, complexing agents - oxyethylidenediphosphonic acid. A solution of ammonium nitrate is used for the alignment of the structure of HCS on the content of nitrogen. To achieve a pH of 5.5 addition use ammonia water. Get liquid fertilizer with the mass ratio of N:P 2 O 5 :2 On=(5-10):7,5:(5-7,5) with microelements. Introduction of microelements in the form of complexions provides stability of liquid fertilizer. Crystallization temperature of utility services is around 0 C, the solution is stable, there is no precipitation.
The disadvantage of this method is a multi-stage process, the poor quality of liquid fertilizers due to the presence of impurities of fluorine and a half oxides, as well as the use of several types of nitrogen-containing chemicals such as ammonia, ammonium nitrate, potassium nitrate, for the equilibrium composition of the fertilizer nitrogen.
Closest to the proposed technical substance and the achieved result is a way of reception of liquid complex fertilizers [RF patent №2142928, CL SV 7/00, publ. 20.12.1999]including neutralization of phosphoric acid nitrogen-containing reagent, Department of insoluble impurities from the obtained solution, and use polyphosphoric extraction phosphoric acid, as nitrogen-containing reagent - ammonia gas and the separation of insoluble impurities spend filtering filter with supporting material, which take the waste product of aluminum fluoride. The result is liquid complex fertilizers containing 10% of nitrogen and 34% of phosphorus in terms of P 2 O 5 .
The disadvantage of this method is the use of polyphosphoric acids and waste production fluoride aluminum and high impurity content, in particular fluorine, and the unbalanced composition of fertilizers on the content of nitrogen and phosphorus.
Purpose of invention - the production of the liquid complex fertilizers with a balanced composition and low content of admixtures fluorine and a half oxides.
This goal is achieved in the proposed method of production of liquid complex fertilizers, including neutralization of phosphoric acid nitrogen-containing reagent, Department of insoluble impurities from the resulting solution, the introduction of a solution of salts and microelements in the presence of complexing agents, and the nitrogen urea reagent is used in aqueous solution, taken in the molar ratio of urea:H 3 PO 4 , equal to 1,5-2,5:1; neutralization process is conducted at the temperature of 95 to 99 degrees Celsius in the presence of calcium agent, taken in the molar regarding calcium:fluorine, equal to 1:2, and the density of the reaction mass 1,22-1.28 g/cm 3 to achieve a pH of the reaction medium 6.5 to 7.2. The sludge separation of insoluble impurities spend at reaching the pH of the reaction medium of 5.0 to 5.9. As calcium agent used limestone, phosphogypsum, dicalcium phosphate.
As salts and microelements use sulphates of zinc, copper, manganese, cobalt, magnesium, ammonium molybdate, potassium iodide and boric acid, and complexing agents - oxyethylidenediphosphonic acid or EDTA sodium (Trilon B).
Summary of the invention consists in the following.
In acidic aqueous environments at high temperatures the decomposition of urea to form ammonia and carbon dioxide:
NH 2 CONH 2 +H 2 O=2NH 3 +CO 2
Ammonia neutralizes phosphoric acid with the formation of mono-ammonium phosphate and diammonium phosphate. This is an increase of pH of the reaction environment on the initial acidic (pH 1) to neutral (pH 6.5 to 7.2).
H 3 PO 4 +NH 3 =NH 4 H 2 PO 4
NH 4 H 2 PO 4 +NH 3 =(NH 4 ) 2 4 HPO
Wet-process phosphoric acid is characterized by a high content of dietary contaminants such as single oxides (R 2 O 3 , includes oxides of Fe 2 O 3 and aluminium Al 2 O 3 ) and fluoric compounds. The impurity content of fluorine in EPA is within 0,5-1,0%, and the total content of iron and aluminum oxides - 1,8-2,2%. Neutralization of phosphoric acid is accompanied by a precipitate of insoluble compounds Queen-oxide and fluorine. The release of sludge starts when the pH of the reaction medium 3.5 to 4.0 and ends at neutral environment.
Optimal consumption urea, taken in the molar ratio of urea:H 3 PO 4 , equal to 1,5-2,5:1. By reducing the consumption of urea lower molar relationship than 1.5:1, not ensured neutrality fertilizers due to lack of reagent. The increase in consumption of urea higher molar relationship than 2.5:1, it is undesirable due to the excess reagent. Excess urea also increases the freezing temperature of the liquid fertilizers, i.e. reduce the stability of the solution of housing and communal services.
The process of neutralization of phosphoric acid in the presence of calcium agent provides minimal impurity content of fluorine in the target product (see table 1). This reaction takes place linking fluoride ion calcium with the formation and release of the precipitate of insoluble calcium fluoride CaF 2 , which provides a high degree of purification of the target product of the admixture of fluorine.
CA 2 + 2F - =CaF 2 p
Calcium agent take in a molar ratio of calcium:fluorine, equal to 1:2, which provides full linking fluoride in CaF 2 and minimal residual content of fluorine in the target product. Lower consumption of calcium-containing agent from a specified number of conditions for full translation of fluoride sludge (experience 2, table 1); increasing waste agent, and also to the loss of part of phosphates from the translation of them into the sediment (experience 4, table 1). As calcium agent use limestone, SASO 3 , dicalcium phosphate, Sanro 4 , phosphogypsum - waste production of wet-process phosphoric acid, consisting mainly of calcium sulphate CaSO 4 .
The maximum emission of compounds Queen-oxide and fluorine in the sediment from the reaction mixture takes place at pH of the reaction medium within a 5.0 5.9 in the presence of calcium agent (see table 1). When the pH of the reaction medium not less than 5.0 ensures completeness of the deposition of impurities fluorine and a half oxides. With the increase of pH over 5.9 observed transition fluorine and a half oxides obtained from sludge into the solution. Therefore, the minimum residual impurity content of fluorine, iron and aluminium in the target product is ensured by precipitation of insoluble compounds at a pH of the reaction medium within a 5.0 to 5.9.
Optimum temperature of the process the neutralization of phosphoric acid by urea solution is 95-99°C. In the conduct of the process temperature below 95 degrees With slowing the rate of decomposition of urea to form ammonia and not achieved by neutral reaction of environment (experience 12, table 2). The process of neutralization at temperatures above 99°leads to increased evaporation of water and increasing density of more than 1.28 g/cm 3 , deterioration of the precipitate (the experience of 13, table 2). The high temperature of the process also requires additional consumption of water for maintaining the required density and leads to the over-expenditure of power resources.
Used as a nitrogen-containing neutralizing reagent urea in the form of water solution provides reception of complex fertilizers balanced composition of the nitrogen and phosphorus. When used as initial raw material concentration of EPA 50-52% P 2 O 5 and 34-36%urea solution provides the reaction mass density 1,22-1.28 g/cm 3 . In the case of EPA with content 36-38% P 2 O 5 , the required density of the reaction mass is achieved with concentrations 40-42% urea solution. In the more concentrated solutions of urea adjustment density of the reaction mass with additional input of water.
After achieving neutrality environment (pH 6.5 to 7.2) in the reaction mass is administered a salt solution of trace elements in the form of complexions. As salts and microelements use sulphates of zinc, copper, manganese, cobalt, potassium iodide and boric acid, and as complexing agents - OEDPK or Trilon b Introduction of salts and microelements in the form of complexions ensures the stability of the resulting liquid fertilizers, eliminates the deposition of sediment.
Use as nitrogen urea reagent allows to obtain a balanced complex liquid fertilizers in which the ratio of nutrients M:P 2 O 5 is 0.65-1:1.
The appropriateness of the chosen interval of process indicators is shown in examples 1, 2 and tables 1, 2.
Example 1. In the reactor download 497,6 kg of water, add 265,7 kg of urea (4,43 of CMOS), dissolved by stirring at 50-60°With. Get 763,3 kg 35%urea solution. Later in the reactor give 250 kg of wet-process phosphoric acid composition, %: 72 H 3 PO 4 (or 52,0 P 2 O 5 ), a 4.9 H 2 SO 4 , 0,62 and 1.8 F O R 2 3 and 4.1 kg of limestone, SASO 3 . Acid is injected 180 kg H 3 PO 4 (1,83 of CMOS) and 1.55 kg of fluorine (81,6 mol), and with limestone 1.63 kg of calcium (40,8 mol). The molar ratio of urea:H 3 PO 4 =2,4:1, the molar ratio of calcium:d =1:2. The density of the reaction mass is 1,23 g/cm 3 . The reaction mixture is heated, stirred at a temperature of 98 C to achieve a pH of the reaction medium 5,6 over 3.5 hours. The reaction mixture is a suspension. The precipitate of insoluble impurities single oxides and fluorides separate filtering. Allocate 28 kg sludge containing 35,6% P 2 O 5 , 15% R 2 O 3 and 5.3% F. the Filtrate is stirred at the temperature to achieve a pH of the reaction medium of 7.0. Just in the process of neutralization is allocated 82,4 kg of carbon dioxide. In a separate reactor in 92,45 l of water dissolve 2 kg of complexing agents OEDPK, 1.6 kg copper sulphate CuSO 4 *5H 2 O, 0,88 kg manganese sulfate MnSO 4 *5H 2 O, 0.45 kg of zinc sulfate ZnSO 4 *7H 2 O, 0.25 kg of cobalt sulphate CoSO 4 *5H 2 O, 0.066 kg of potassium iodide KI, 2.3 kg boric acid H 3 BO 3 . Received 100 kg of a solution of salts and microelements are added to the filtrate. The result is 1000 kg of liquid complex fertilizers density 1,20 g/cm 3 balanced composition, containing 12% nitrogen, 12% of phosphates in recalculation on P 2 O 5 . The impurity content of fluorine is 0,006% and 0.02% single oxides R 2 O 3 . The degree of purification from impurities fluorine is 96%, from single oxides - 95,5%. The content of microelements in the product, %: 0,04 boron, 0,04 copper, 0.02 manganese 0.01 zinc, 0.005 cobalt and 0.005 iodine.
Table 1The dependence of the content of fluorine and a half oxides from pH of the reaction medium in the presence of calcium agent
Conditions of carrying out of experiments
The composition of EPA: 72% H 3 PO 4 , 4.9% of H 2 SO 4, 0,8% F and 1.8% R 2 O 3 ; molar ratio urea:H 3 PO 4 =2,3:1 as calcium agent taken limestone (experiments 2, 3, 4), phosphogypsum (experience 5) and dicalcium phosphate (6), process temperature 98 C, the density of the reaction mass 1.24 g/cm 3 . In experiment 1, the process is conducted without adding calcium agent
Experience 2
Experience 3
Experience 4
Experience 5
Experience 6
pH environment
Experience 1
Limestone
Limestone
Limestone
Phosphogypsum
The dicalcium phosphate
Mole. attitude
Mole. attitude
Mole. attitude
Mole. attitude
Mole. attitude
Ca:F=0,8:2
Ca:F=1:2
Ca:F=1,1:2
Ca:F=1:2
Ca:F=1:2
F, %R 2 O 3 , %
F, %R 2 O 3 , %
F, %R 2 O 3 , %
F, %R 2 O 3 , %
F, %R 2 0 3 , %
F, %R 2 O 3 , %
1,3 0,2 0,45 0,20 0,45 0,20 0,45 0,20 0,45 0,20 0,45 0,20 0,45 4,0 0,12 0,25 0,10 0,20 0,05 0,15 0,04 0,15 0,05 0,15 0,05 0,15 4,5 0,11 0,25 0,10 0,18 0,04 0,10 0,04 0,10 0,04 0,10 0,04 0,10 4,9 0,10 0,24 0,04 0,17 0,03 0,05 0,03 0,05 0,03 0,05 0,03 0,05 5,0 0,10 0,24 0,03 0,10 0,005 0,02 0,005 0,02 0,005 0,02 0,005 0,02 5,9 0,10 0,24 0,03 0,10 0,005 0,02 0,005 0,02 0,005 0,02 0,005 0,02 6,0 0,10 0,24 0,04 0,15 0,01 0,04 0,01 0,04 0,01 0,04 0,01 0,04 6,5 0,11 0,25 0,06 0,16 0,02 0,05 0,02 0,05 0,02 0,06 0,02 0,06 7,2 0,12 0,25 0,07 0,16 0,03 0,06 0,03 0,06 0,03 0,10 0,03 0,091. Process for production of liquid complex fertilizers, including neutralization of phosphoric acid nitrogen-containing reagent, the sludge separation insoluble impurities from the resulting solution, the introduction of a solution of salts and microelements in the presence of complexing agents, wherein as nitrogen urea reagent is used in aqueous solution, taken in the molar ratio of urea:H 3 PO 4 , equal (1,5-2,5):1, neutralization process is conducted at temperatures 95-99 C and density of the reaction mass 1,22-1.28 g/cm 3 to achieve a pH of the reaction medium 6.5 to 7.2 in the presence of calcium agent, taken in the molar ratio of calcium:fluorine, equal to 1:2, and the sludge separation of insoluble impurities performed at achieving the pH of the reaction environment of 5.0 to 5.9.
2. The method according to claim 1, wherein as calcium agent use limestone, phosphogypsum, dicalcium phosphate.