SU1114668A1 - Method for producing complex fertilizers - Google Patents

Abstract

METHOD OF OBTAINING COMPLEX FERTILIZERS, inclusive) decomposition of the phosphate raw material of nitric acid in the presence of phosphoric acid, ammonization of the mixture by adding the phosphorus-containing component, mixing with the capillary component and granulating, in order to increase the PjOjucgB product, the product prepared. its water-soluble form, phosphoric acid is pre-introduced into the initial phosphate raw material to achieve a T: W ratio of 1: 0.2-0.5, 20-50% of the required amount of phosphoric acid the slots are introduced together with nitric acid, and the remaining 80–50% ammoniated to pH 4.4 4, 9 phosphoric acid is taken as the phosphorus-containing component. (L

Description

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This invention relates to methods for producing KOhmneKCHMX fertilizers widely used in agriculture.

A method for producing complex fertilizers by decomposing phosphate raw materials with nitric acid at a concentration of 55-60%, precipitating calcium nitrate precipitates by crystallization from a cooled nitrophosphate solution, treating the nitrogen-phosphorus solution with a solution of ammonium sulphate to completely remove calcium oxide in the form of sulphate by neutralizing with amyamers, neutralizing amyamers. and the subsequent mixing of the obtained melt with potassium salts during granulation lj.

The disadvantage of this method is a lot of staging and low amount of nutrients (36-46%).

The closest to the proposed technical essence and the achieved result is a method of obtaining complex fertilizers, including the decomposition of phosphate raw materials with nitric acid in the presence of phosphoric acid, ammonization of the mixture by adding a phosphorus-containing component, mixing with potassium component and granulation. According to this method, 50-60% nitric acid is decomposed, followed by the addition of phosphoric acid with a concentration of 30 to 50% PjO. The resulting mixture is ammoniated to a pH of 2.4-4.5. Then phosphoric acid is again added to the ammoniated mixture and ammoniated again to a pH of 5.0-6.0. At the same time, before the first ammonization, 10-40% of phosphoric acid of the total amount is introduced, and before the second - the rest. The neutralization temperature in both stages IIO-ISO C. In the second stage of neutralization, sulfuric acid is introduced together with phosphoric acid to partially remove calcium oxide / carbonate.

The disadvantage of this method is the low content of PjOg (30-48%) and PjOc in the final product (45-50%).

The purpose of the invention is to increase the content of PjOe in the finished product while increasing its water-soluble form.

 The goal is achieved by the fact that according to the method of obtaining complex fertilizers, including the decomposition of phosphate raw materials with nitric acid in the presence of phosphoric acid, ammonization of the mixture by adding the phosphorus-containing component, mixing with the potassium component and granulation, phosphoric acid is preliminarily added to the starting phosphate raw material. : W equal to 1: 0.2-0.5, 20-50% of the required amount of phosphoric acid is administered together with nitric acid, and as the phosphorus-containing component taking remaining 80-50% ammoniated to pH 4,4-4,9 phosphoric acid.

The essence of the method is as follows.

Due to the pre-wetting of phosphate phosphate with phosphoric acid, part of the fluorine and carbon dioxide formed during its decomposition is removed into the gas phase due to the relatively low moisture content of the reaction mass. Thus, the amount of fluorine in the nitric-phosphoric acid solution is reduced, and the gas phase formed at this stage does not contain impurities, in the form of nitrogen oxides. In the process of mixing phosphate raw materials and phosphoric acid, a loose mass consisting of a mixture of phosphate substance and mono-calcium phosphate hydrate has a larger contact surface with liquid phases, which intensifies the decomposition of phosphate raw materials in nitric acid, with little foaming.

The method is carried out as follows.

Phosphate raw materials and a part of phosphoric acid are loaded into the mixer, intensively mixed, and the resulting mass is fed to the decomposition with nitric acid into the reactor, where 5060% nitric acid is mixed with 20-50% of the rest of the phosphoric acid. The decomposition takes 40-60 minutes, then NP-pacTBop is filtered from the sludge if necessary, and the filtrate with a pH of 1 is mixed with the remaining 80-50% of phosphoric acid ammoniated to a pH of 4.4-4.9. After mixing, the resulting NP-pulp is ammoniated with ammonia gas to a pH of 4.4-4.9, then the potassium salt is added, if necessary, and granulated.

31114668

The appropriateness of the selected corresponding; Wear T: W in the reaction pulp after adding phosphoric acid to the raw material is illustrated in Table. 1 (data are given for alpatitovogo raw materials).

Table 1

Continued table. 2

I As can be seen from the table. 2, a decrease in phosphoric acid at the decomposition stage leads to an increase in the content of the finished product, but at the same time .. The proportion of PjOsgai i in it drops. With an increase in the amount of phosphoric acid in the decomposition stage, the content of nutrients in the product decreases (PjOstjcB). The appropriateness of the selected pH range during the ammonization of phosphoric acid is illustrated in Table. 3

Table 3

As can be seen from the data table. 1, a decrease in the proportion of acid in the pulp below 0.2 h leads to a decrease in the share of nutrients in the fertilizer and a decrease in PjOc water-soluble in it. As the proportion of acid increases, the nutrient content of the fertilizer increases slightly, but it also introduces a lot of water and. The fluorine injected remains completely in solution, which contaminates the final product. In tab. 2 phovania phovana expediency of choice. The amount of phosphoric acid introduced at the stage of decomposition together with nitric acid (data are given for Karatau phosphate phosphate). Table 2 As can be seen from table 3, a decrease in pH to 4.7. leads to a decrease in the content of Р205ЧС8 Р Р Ь1 over 4.9 with an increase in P20sucR ВDt a sharp decrease in PjOgeoJV Example 1. 100 kg / h Kovdorsky apatite (CaO 52.8%, PjOy 36.2%, MgO 4.37%) is mixed with 20 kg / h of extraction phosphoric acid, stirred to obtain a homogeneous mass (T: W 1: 0.2), then decompose 239.6 kg / h of 55% nitric acid, mixed with 61.2 kg / h of phosphoric acid acid. The resulting mass is filtered, the filtrate in the amount of A13.6 kg / h is mixed with 61.2 kg / h of ammoniated (80%) to pH 4.4 acids, the mixture is monitored to pH 4.4 NP-pulp in the amount of 527.7 kg / H with a nitrogen content of 13.2%, Pj g cft50%, PjO5 water 50% is directed to granulation or mixing with the potassium component.

Example 2. 100 kg of apatite concentrate are mixed with 35 kg / h of extraction phosphoric acid, stirred to obtain a homogeneous mass (T: W 1: 0.35), then 194.3 kg / h are decomposed with 55% nitric acid in mixtures with 50.7 kg / h of phosphoric acid. The resulting mass in the amount of 369.9 kg / h is filtered, the filtrate in the amount of 361.4 kg / h is mixed with 57.3 kg / h (50%) ammoniated to a pH of 4.7, the mixture is monitored to a pH of 4.7 and NP- the pulp in the amount of 446.7 kg / h is directed to granulation and mixing with potassium salts. The content of PjOgvjce finished product 51.5%, Pj05.6oA.57%.

Example 3. 100 kg / h of Karatau phosphorite flotation concentrates are mixed with 5P kg / h of extraction phosphoric acid, stirred until a homogeneous mass (T: W 1: 0.5), then decomposed 176.8 kg / h 55% - nitric acid in a mixture of 16 kg / h of phosphoric acid. The resulting mass in the amount of 342.8 kg / h is filtered, the filtrate in the amount of 294.3 kg / h is mixed with 59.8 kg / h (65%) of phosphoric acid ammoniated to pH-4.9, the mixture is monitored to pH 4.9 and NP-pulp is sent for granulation. Content 38.7%, PJ 0590ft 64, 2%.

The use of the proposed technology allows in comparison with the known increase in the nutrient content in the finished product. So, with

the use of poor raw materials (for example, Karatau phosphorites), the PjOjuce content increases in the finished product from 30 to 37-50%, and when using apatite raw materials from 48 to

50-54%. The content of P2O5eoik in the finished product is increased from 45-50 to 51-68%.

Claims (1)

METHOD FOR PRODUCING INTEGRATED FERTILIZERS, including decomposition of phosphate feedstock of nitric acid in the presence of phosphoric acid, ammoniation of the mixture with the addition of a phosphorus-containing component, mixing with a potassium component and granulation, characterized in that, in order to increase the content of the finished product while at the same time watering it up, phosphoric acid is preliminarily introduced into the initial phosphate feedstock until the ratio T: G is reached, equal to 1: 0.2-0.5, 20-50% of the required amount of phosphoric acid is introduced ovmestno with nitric acid, as well as take other phosphorus component 80-50% ammoniated to pH 4,4 4,9 with phosphoric acid. SU_ ₍₁₁ , 1114668. > 1 1114668 I