SU1724653A1 - Method of production of enriched superphosphate - Google Patents

Abstract

The invention relates to a technique for producing enriched superphosphate by decomposing a phosphate feedstock with a mixture of sulfuric and phosphoric acids in the case of W: T. equal to (2,5-3,5): 1, the introduction of phosphorite flour into the resulting pulp with a ratio of pulp: phosphorite flour equal to (3-2): 1. The product is dried and granulated. 1 tab.

Description

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This invention relates to a technique for producing enriched superphosphate.

A known method of producing enriched superphosphate is the decomposition of a phosphate raw material with a mixture of sulfuric and phosphoric acids using phosphoric acid pulp as phosphoric acid, obtained by decomposing a phosphate raw material with cream-hydrofluoric acid.

The disadvantages of this method are the long duration of the technological cycle associated with the need for warehouse processing of the chamber product for 6 days, a significant fluorine content in the product of 1.15-1.3% F, and the insufficient strength of the granules of the granulated product, which is only 1.6-1.7 MPa.

The purpose of the invention is to intensify the process by reducing the duration of the production cycle and improving the quality of the finished product by reducing the fluorine content and increasing the mechanical strength of the granules.

The goal is achieved by the fact that in the method of obtaining enriched superphosphate, which includes the decomposition of phosphate raw materials with a mixture of sulfuric and phosphoric acids, followed by granulation and a dried product, the decomposition is carried out at W: T equal to (2.5-3.5): 1 and at. the resulting pulp is injected with phosphate flour at a pulp: phosphorite flour ratio of (3-2): 1.

The proposed method makes it possible to eliminate the storage stage of product ripening, which makes it possible to shorten the duration of the technological cycle and intensify the process, as well as improve the quality of the product by reducing the fluorine content to 0.5-0.85% and increasing the mechanical strength of the granules to 2.2-2, 3 MPa.

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Example 1. Required amount of dilution solution,% by weight: P20s 17.0; 50s 1,5; Рв20з 0.5; AfcOa 0.4; F 1.0, poured into the reactor, heated to 50 ° C and with stirring, pour 100 g of apatite concentrate. Then, within 20-30 minutes, 73 ml of sulfuric acid with a concentration of 75% (on the basis of the preparation of W: T 2.5: 1) are introduced, the temperature is raised to 75-80 ° C and stirring is continued for 2.5- 3 hours. After the indicated time has elapsed, 186 phosphorate flour (based on a ratio of pulp: phosphate rock 3.0: 1) is introduced into the pulp with gradual stirring, the mass is placed in a drying oven, where it is kept at 110-115 ° C within 45 minutes, after which the liquid phase formed on the pulp surface is drained, and the solid part is dried at 110-115 ° C for another 2.5-3 hours. Then t is recovered, cooled, pulverized and granulated using a liquid phase to wet a fertilizer in the process of granulation.

The granulation conditions, the moisture content of the charge, the number of revolutions of the drum, the pelleting time, the amount of retour, etc. similar to those used in production.

The obtained granulated enriched superphosphate contains, in wt.%: P20, total 27.1; R.05usv 25.50; P205slob 2.1; F 0.85; moisture 2.0; Krasl 94,10. The strength of the granules 2.1 MPa.

Example 2. The experiment was carried out analogously to example 1, but G: T was 3: 1, and the ratio pulp: phosphate flour was 2.5: 1. The obtained granulated enriched superphosphate contains, wt%: Р205 total 28.05; P205usv 26.70; P205sobl 2.0; F 0.70; moisture 2.8; Kra3l 95.19. Durability granulated 2.2 MPa.

Example 3. The experiment was carried out analogously to example 1, but L: T was 3.5: 1, and the ratio pulp: phosphate flour was 2: 1. The obtained granular enriched superphosphate contains, wt%: Р20 total 29.07; Р205Усв 27.90: Р205 сощ 2,2; F 0.5; moisture 2.7; Krasl 95.98. The strength of the granules is 2.3 MPa.

The justification of the proposed intervals of parameters in accordance with the achieved effect compared with the known ones is presented in the table.

The table shows that the introduction of the process in the proposed parameter ranges (examples 1-3) allows to intensify the process by eliminating the storage stage of product maturation and reducing the duration of the technological cycle to improve product quality by reducing the fluorine content in it and increasing the mechanical strength of the granules.

A decrease in the ratio W: T of less than 2.5: 1 (Example 4) is impractical, since it leads to a decrease in the degree of decomposition of the phosphate raw material. An increase in the ratio W: T of more than 3.5: 1 (Example 5) is also impractical, since it leads to an increase in the dilution solution flow rate and a decrease in the strength of the granules.

An increase in the pulp: phosphoric flour ratio of more than 3: 1 (Example 6), i.e. a decrease in the amount of phosphate rock is impractical, since it leads to an increase in the content of P20b in the product, a decrease in the ratio of pulp: phosphoritic flour less than 2: 1 (Example 7), i.e. an increase in the amount of phosphate rock is also impractical, since in this case a part of the phosphate rock remains undecomposed, which leads to a loss of phosphate raw materials.

Claims (1)

Invention Formula The method of obtaining enriched superphosphate, including the decomposition of phosphate raw materials with a mixture of sulfuric and phosphoric acids, granulation and drying of the product, which is characterized by the fact that, in order to reduce the duration of the technological cycle and improve the quality of the finished product by reducing the fluorine content and increasing the mechanical strength of the granules , decomposition is carried out at W: T equal to (2.5-3.5): 1, and phosphate flour is introduced into the resulting pulp at a ratio of pulp: phosphate flour equal to (3-2): 1. (2.5-3.5): 1 Famous 1.5: 1 ,five An increase in the ratio of pulpagophosphoric flour to more than 3: 1, that is. reducing the amount of phosphate rock is impractical because it leads to an increase in the content of PЈ05cgo5- in the product. A decrease in the ratio of pulp: phosphorite flour is less than 2: 1, tie.- to waste phosphate raw materials 1.15-1.30 95.6-95.8 1.6-1.7 -j to 45. About ate with O1