SU606848A1 - Method of obtaining superphosphate - Google Patents

Description

(54) METHOD FOR PRODUCING SUPERPHOSPHATE

I

This invention relates to a technique for producing superphosphate-phosphorus-containing mineral fertilizer used in agriculture.

Methods are known for producing superphosphate containing 14-55% of digestible PgOj by treating the phosphate raw material with acids, such as sulfuric and / or phosphoric, followed by maturation of the superphosphate mass and its processing into the finished product.

In order to obtain dehydrated phosphate fertilizers, a superphosphate mass has been proposed, after aging, to treat superheated steam with a temperature of 150-180 ° C, followed by air drying at 220 ° C l.

The disadvantage of the process is the complexity of the process and the relatively low content of water-soluble PyOg in the final product.

A known method of producing superphosphate by treating the phosphate raw material with acids followed by maturation of the superphosphate mass in the presence of water vapor 2.

The disadvantage of this method is to reduce the degree of decomposition of phosphate raw materials.

The aim of the invention is a more complete decomposition of the phosphate raw material.

The goal is achieved by the fact that the maturation of the superphosphate mass, resulting from the acid decomposition of the phosphate raw material, is carried out at a partial pressure of water vapor in the gas phase of 140-250 mm Hg. The partial pressure of water gifts is created by saturated water with a temperature of 120-140 ° C.

The method makes it possible to increase the degree of decomposition of phosphate raw material at the aging stage by 3-8%.

Example 1. 100 g of apatite concentrate (39.4%) are mixed with 117 g of 60% sulfuric acid in a batch mixer for 5-6 minutes at. The resulting mass is transferred to a temperature-controlled vessel, in which it is treated for 60 minutes with saturated water with steam at a temperature of 120 ° C, maintaining the pressure of water vapor in the gas phase above the superphosphate mass equal to 250 mm Hg. Art. Then the mass is discharged and crushed .. At the same time, 210 g of the crumbly mass of the following Sastava,%: P2O50b1d. 18.7; . 16.6; moisture 19%. The degree of appatite decomposition in the mass is 88.5% as compared with 85% for the product under similar conditions, but in the absence of steam. The superphosphate is held for 5 days at 40-50 ° C, neutralized with chalk, granulated, and dried. At the same time, 185 g of product (PjOj, e.g., 20.3%, P OooObsch. 21.2%) are obtained, the decomposition degree of which is 96%.

Example 2. 25 t / h of apatite concentrate (39.4%, 25.6 t / h of sulfuric acid concentration of 67.8%) are fed to the continuous mixer. The residence time of the mass in the mixer is 5-6 minutes, temperature 110-115 seconds. the pulp flows into a rotating continuous chamber with a diameter of 7.1 M and a height of 2.7 m, equipped with devices for supplying water vapor and water. Using these devices, 1.4 t / h of water vapor are fed into the continuous chamber (temperature , pressure 2.2 atm) and 0.6 mw, maintaining the partial pressure of water vapor in the gas phase above su perphosphate mass equal to 180 mm Hg. The residence time of the mass in the chamber is 70 minutes. The product (48.8 tons), cut out of the chamber by the carousel, has the following composition,%: 20.2; P Oyusv. 17/8 (Kp88, 3%), moisture 14.5. The product obtained by the method implemented in industry (without treatment with steam and water) usually has the following composition,%: PO "o6m. 21.0; PjOjycB. 17.7 (Kp84.5% ); moisture 12.

The superphosphate is stored in a warehouse for ripening, neutralized with chalk, granulated and dried, thereby obtaining 45.8 t / h of a product containing,%: RdOsv. 20.5% p2050bsch. 21.5 (degree of decomposition of apatite 95.5).

Example 3. In a continuous mixer, 10 t / h of apatite concentrate (39.4% PjOy) of 19.2 g / h of evaporated extraction phosphoric acid with a concentration of 52.5% P Oj are fed. The residence time of the mass in the mixer for 6.5 minutes, temperature. The resulting pulp flows into a continuous rotating chamber equipped with a device for supplying water vapor and water. Using these devices, 0.6 t / h of saturated water vapor (temperature) and 0.1 m / h of water were continuously introduced into the chamber, maintaining the partial pressure of water vapor in the gas phase above the superphosphate mass of 140 mm Hg. The residence time of the mass in the chamber is 90 minutes. The product (28.4 tons), cut out of the chamber by the carousel, has the following composition,%: PgOuObsch. 49.4; PgOjycB.

45.4 (Cr 71.2%) and moisture 16.2. The product obtained by the method implemented in industry (without treatment with steam and water) usually has the following composition,%: RdOdObsch. 49.5; .

44.3 (Cd 63.3%); moisture 11.5. The superphosphate is kept in stock for maturation, neutralized with chalk, granulated and dried, thus obtaining 26.6 t / h of a product containing,%: P2O5 Total.

52.7; R 05Usv. 52.1 (Kr95.9%).

Claims (2)

1. A method of producing superphosphate by treating a phosphate raw material with acids followed by maturation of the superphosphate mass in the presence of water vapor, characterized in that, in order to more completely decompose the phosphate raw material, aging is carried out at a partial pressure of water vapor in the gas phase of 140 250 mm Hg. Art. 2. The method according to claim 1, characterized by the fact that the partial pressure of water vapor is created by saturated water vapor with a temperature of 120-140 C. Sources of information taken into account in the examination: 1 USSR Copyright Certificate 230837, cl. From 05 To 13/06, 12.07.67. 2. USSR author's certificate 216759, cl. From 05 В 1/02, 03.03.67.