SU881092A1 - Method of producing fluorine-free phosphates - Google Patents

Description

one

The invention relates to methods for the production of defluorinated phosphates used as a mineral additive to feed means or as fertilizer.

A known method for producing defluorinated phosphates, including the treatment of phosphorus-containing raw materials with sulfur dioxide at a temperature of 100 - 1200 ° C.

The disadvantage of this method is that the fluorine content in the final product is 0.5%, which limits its use as kopMOBbix additives.

The closest to the invention to the technical essence and the achieved result is the method of obtaining 1 defluorinated phosphates by thermal processing of phosphorus-containing raw materials with the addition of phosphoric acid in the presence of water vapor. According to this method, phosphate is mixed with phosphoric acid containing 41% Pg O f, at the rate of 109 kg of acid per ton of phosphate with a content of 36 - 38%. The mixture is heated in rotary kilns to 1340-1380 ° C in the presence of water vapor. The process time is 12-13 hours. The fluorine content in the final product is not more than 0.2% D 21.

The disadvantage of this method is the length of the process, high temperature and high consumption of phosphoric acid.

The purpose of the invention is to reduce the process time, reduce its temperature and the consumption rate of phosphoric acid, while maintaining a low fluorine content in the finished product.

This goal is achieved by the fact that, according to the method of obtaining defluorinated phosphates by thermal processing of phosphorus-containing raw materials with the addition of phosphoric acid in the presence of water vapor, heat treatment is carried out in the presence of elemental sulfur, taken. the amount of 0.520 0.7% per ton of P Oj syr and with a ton of grinding of 0.05-0.1 m.

From the data presented in table. 1, it follows that, the optimal amount of elemental sulfur

25 is 0.5-0.7% per tonne PjOy. Reducing sulfur consumption of less than 0.5% degrades all process indicators. An increase in the amount of sulfur introduced by more than 0.7% per ton of R., 0 does not lead to an improvement in technological parameters.

However, it is impractical because of the increased consumption of sulfur, which is not economically profitable.

In tab. Figure 2 shows the data reflecting the effect of the dispersion of the sulfur introduced on the technological parameters.

From the data presented in table. 2, it follows that with a fineness of grinding of 0.05-0.1 mm sulfur introduced into the process, the best results are observed. When the sulfur grinding fineness is more than 0.1 mm, the results of the process deteriorate dramatically, which is probably explained by the mechanism of diffusion processes of hydrothermal processing, and when the grinding finishes less than .0.05 mm, large amounts of sulfur are carried out with the exhaust gases, which impair the bleaching process

Example l.Ha production of 1000 kg of defluorinated phosphates serves 95 kg of 41% phosphoric acid and 986.7 kg of phosphorus-containing raw materials of the following composition

CaO - 51.1

P.Oi -37.6%

F -0,81

0.37

, 0 +

COj -1,88

I.p.

Mgo -3.5 2.74 K.O. and 2.1 kg of elemental sulfur with a fineness of 0.05 mm, which corresponds to 0.5% per ton. The process is carried out in a tempering furnace for 10.5 hours. The amount of sulfur introduced per ton is A 0.05 0.10 0, 2,23 0,35 0,50 0,60 Phosphoric consumption, 109 109 109 109 100 95 at the residence time of the material, h 12 12 12 12 11.5. 10.5 10, SODrr vaniv fluorine in the finished product, 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.1 Theoretical fuel consumption,. 1500 1500 1500 1450 1400 1380 1370

at. The fluorine content in obfluorinated phosphate is 0.18%.

Example 2. 95 kg of 41% phosphoric acid and 986.7 kg of phosphorus-containing raw materials of the same composition as in Example 1 and 2.5 kg of elemental sulfur with a fineness of 0.1 mm are fed to the production of 1000 kg of defluorinated phosphates, which corresponds to 0.6 per tonne PjOs. The process time to obtain a product with a content of 10.0 hours, temperature -

Example 3. 95 kg of 41% phosphoric acid and 986.7 kg of phosphorus-containing raw materials of the same composition as in Example 1, and 2.8 kg of elemental sulfur with fine grinding of 0.063 mm, corresponding to 0 , 7% per tonne PjO; The process time to obtain a product with an F content of 0.18% is 10.0 hours, the temperature is 1260 ° C.

The method allows to obtain a conditioned product with a fluorine content of 0.18%, with a reduced consumption rate of phosphoric acid per ton of raw material by 8-13%, to reduce the process time by 20%, to reduce the temperature and fuel consumption by 9%.

Table 1 0.70 0.80 1.00 1.20 1.50 95 97 95 100 95 0.5 10.5 10.5 10.0 10.0, 18 0.18 0.18 0.18 0, 18 360 1370 1360 1360 1360

table 2

Sulfur grinding tonin, mm (amount of sulfur injected - 6 kg) 0.03 0.05 0.063 0.1

Claims (2)

Phosphoric acid consumption per ton of raw material, kg Material residence time, part 11.6 10.0 10.5 10.0 Content of fluorine in the finished product, 18 0.18 0.18 0.18 those,% Formula of the invention The method of obtaining defluorinated phosphates by heat treatment of phosphorus-containing raw materials with the addition of phosphoric acid in the presence of water vapor, characterized in that, in order to shorten the process time, reduce its temperature and the consumption rate of phosphoric acid while maintaining a low fluorine content in the finished product, thermal 109 109 109 95 100 0.16 0.4 1.5 11.5 12.0 12.0 0.18 0.18 0.18 The treatment is carried out in the presence of elemental sulfur, taken in an amount of 0.5-0.7% per ton of raw material and with a fineness of grinding 0.05 - 0.1 mm. Sources of information taken into account in the examination 1, USSR Author's Certificate No. 91563, cl. From 05 To 13/02, 1949. 2.Volfkovich S. Hydrothermal processing of phosphates for fertilizers and feedstuffs. M., Himi, 1964, p. 11-15.