SU994457A1 - Process for producing complex fertilizer from phosphorus-bearing raw material - Google Patents

Description

The invention relates to methods for producing complex fertilizers from phosphate ores and can be used in the direct chemical processing of poor phosphate ores.

A known method of producing complex fertilizers from enriched phosphate-containing ores is based on the treatment of phosphbrits with concentrated hydrochloric acid with the following separation of metal chlorides with organic solvents LlJ.

However, this method is effective only in relation to rich in content (28-41%) concentrates free from impurities of sesquioxides of iron and aluminum, and for poor phosphates with an Og content of 20% and below, including iron and aluminum-containing minerals, it is not suitable due to the high consumption of hydrochloric acid spent on the opening of associated impurities, as well as the difficulties associated with the removal of large poorly filtered sludge and contamination with impurities of the obtained fertilizers.

The closest in technical essence to the invention is a method of obtaining complex fertilizers from

phosphate ores, in which the ore containing, wt.%: 12.65; CaO 21.18; ,, 12.04; 6.81, is subjected to decomposition with dilute hydrochloric acid with a concentration of 1-4.% At a ratio of T: W in the pulp equal to 1: 8-1: 20 and a temperature of 4-60s. After filtering from the sludge, the phosphoric acid obtained is processed to C2 fertilizer.

The disadvantage of this method is the low productivity of the process of obtaining complex fertilizer,

15

a% associated with a low concentration in the leaching solution (1-1.5%), as well as with a large volume of the liquid phase, which, in turn, dramatically reduces the filtration performance of both the production leach solution from the insoluble residue and fertilizer itself after neutralization; Large consumption of hydrochloric acid.

25

The purpose of the invention is to increase the productivity of the process of obtaining complex fertilizer by increasing the concentration in the leaching solution and reducing the consumption of sulfuric acid. The goal is achieved by the fact that according to the method of obtaining complex fertilizer from phosphorus-containing raw material by decomposing it with dilute hydrochloric acid with a concentration of 1-4%, separating the production solution from the insoluble residue by filtration and then processing it for fertilizer, decomposition is carried out differentially and each subsequent portion raw materials and acids are introduced before the content of the production solution (equal to 15-25%, while maintaining a constant T: W pulp. The amount of hydrochloric acid in each of the next stage, take less than stoichiometric, taking into account the degree of decomposition of phosphoric acid-containing phosphoric acid raw material contained in the production solution from the previous stage .. The amount of phosphorus-containing raw material in each subsequent stage is calculated empirically, taking into account the liquid phase consumption for wetting and reducing the hydrochloric acid consumption. 15–25% in solution, reach 15–20% of the production solution. Repeated differential use of a leaching production solution, which also contains hydrochloric and phosphoric acid, to decompose the fresh feedstock in the subsequent stages leads to the accumulation of the useful component in the salt-phosphoric acid extract, and this, in turn, allows em significantly reduce the consumption of hydrochloric acid; reduce many times the volume of the liquid phase; to cut

Concentration

Removing the solution, wt.%, Weight,%

9.6

9.6 11.8 12.5

14.2

15 18.6

10 15 18.0

22.3

22.7

20

9.6

0.46 12.5 0.5

0.6

13.2 0.54 13.9

14.7

0.93 0, 61 is the number of filtration cycles, since there is no need to filter both the sludge and fertilizer after each decomposition cycle, as well as by reducing the total volume of the mass to be filtered. According to the invention, the Fresfat-containing ore undergoes decomposition with dilute hydrochloric acid for 15–20 minutes, then a fresh calculation portion of the raw material and SALT acid is loaded into this reaction mass, but a smaller amount, including phosphoric acid, passed into the solution, which also participates in the decomposition raw materials, and continue to leach for the same time, etc. Thus, the leaching product solution is repeatedly used to decompose the starting phosphate raw material. With a total T: W of pulp equal to 1: 2-3, the solution is filtered from the insoluble residue (sludge) and used again to leach the raw material until the concentration in the solution reaches the desired condition. Further, this solution is filtered from the sludge and processed for fertilizer , Table 1-3 shows the results of studies on the multiple differential use of the production leaching solution for the decomposition of phosphate rock of the Verkhnekamskoye deposit of the following composition, weight,%: PjOg- 12.65; CaO 21.18; , 12.04; , 6.81. Experimental data on phosphorite decomposition of the Verkhnekamskoye phosphorus deposit are presented in Table 1, Table

P; tl6Ji. one

From the data TaeSJi.I can be seen that with. the decomposition of phosphorite by phosphoric acid with an increase in its concentration from 1.8% (which corresponds to its content upon single leaching) to 50%; the extraction of P2 OB phosphate in the solution increases from 9.6 to 59.2%. In this case, significant removal of aluminum and iron impurities into the solution is observed, thereby increasing the selectivity coefficient. This is explained by the fact that when phosphoric acid is leached out, the process of decomposing phosphate occurs more selectively than hydrochloric acid. Using these data in the hydrochloric acid leaching of phosphate, knowing the content in the solution after the previous leaching stage, it is not difficult to calculate the amount of hydrochloric / acid required before decomposition of phosphate in the next stage, taking into account that phosphoric acid itself is a phosphate solvent. In this case, in order to withstand the initial optimal T: W pulp in each leaching cycle, the amount of solid in the reactor is reduced by reducing the consumption of hydrochloric acid in subsequent cycles and the consumption of the liquid phase to wet the phosphate. The dependence of the extraction of the O solution at 10-fold use of the production solution is leached, and for the decomposition of phosphate from the Verkhnekamskoye deposit with the initial one, are presented in Table. 2; Table 2 Notes e. From the data in Table 2, it can be seen that with a 10-fold use of the production leach solution to decompose phosphate at constant T: W pulp relative to the liquid phase after previous leaching cycles, the amount of phosphate loaded into the reactor decreases from 100 to 29 g. At the same time, the concentration of hydrochloric acid is reduced 4 times with the same extraction into the solution, and its concentration is increased from 12.6 to 113.19 g / l. Next, the production solution after the X-th cycle is filtered from the insoluble residue and processed for fertilizer. Obtained by the proposed method complex fertilizer contains,%: 38-42

Continued table. 2 When phosphorite was diluted in each cycle with the exception of the 1st, a leaching solution from the previous cycle was used. (including 90-98% of the absorbed form of the water-soluble form of 3-6%) CaO 32-38; N 6-10. I The production solution from the X-th cycle, after filtration from the insoluble residue, can be used further to decompose the phosphate raw material and increase the content. in solution up to 200 g / l and higher, as a result of which the number of filtration cycles of both the sludge and the fertilizer itself will be reduced by 15-20 times compared with the known. The dependence of the extraction into the solution at 20-fold use of the production leaching solution for the decomposition of phosphorite from the Richnekamsk deposit at the initial one is presented in Table 3. Table 3 Notes From the data of Table 3 it can be seen that at 15-20-fold use of the production solution for further decomposition of the phosphate raw material, the content of Ej, Og in the solution rises to 20-25, which makes it possible to significantly increase the productivity of obtaining complex fertilizer and reduce the consumption hydrochloric acid. After the XY cycle, the content in the liquid phase is 18.8% or 25.9%. However, it follows from the data of Table 1 that at this concentration of phosphoric acid the degree of decomposition of the phosphate raw material is 27.6%, i.e. 72.4% of the raw material will remain underdeveloped. This is the amount of raw material that is used to calculate the hydrochloric acid for the next XY cycle. The HCE concentration is 1.75% at T: W pulp of 1:10. Although in this case the amount of acid is less than stoichiometric, the degree of phosphate decomposition is 99.4%. Example. 100 g of ore from the Verkhnekamskoye deposit is placed in a 2-liter reactor, 1000 ml of 4% hydrochloric acid () is poured in, and washed for 15 minutes at room temperature. A small sample of the liquid phase is taken to determine the Ej-O. Then, taking into account the solution, which is involved in the decomposition in the next cycle, hydrochloric acid is added to the same solution. e. In the XI cycle, the production solution after the X cycle, filtered from the insoluble residue, was used to decompose the phosphate of hydrochloric acid. so that its concentration is 3.6% instead of the initial 4%, 96 g of ore is loaded there and decomposed again for 15 minutes. A sample of the liquid phase is taken again to determine the P-j-Off h, and the decomposition is repeated as described, taking into account the concentration of P, O in the leaching solution in the following stages when calculating hydrochloric acid. After 10 times use of the production target solution, the latter is filtered out. The filtrate and precipitate are measured and analyzed. Next, the filtrate is neutralized with a 25% ammonia solution to a pH of 6.2. The resulting pulp is filtered, the resulting complex fertilizer precipitate is obtained and analyzed. The fertilizer content is 41.6%; CaO 30.7%; N 8.1%. Thus, it can be seen from the above data that the proposed method allows, in comparison with the known method, to increase by 15–20 times the concentration in the production solution directed to the production of fertilizer; reduce the consumption of hydrochloric acid by 1.5–2 times and by 30–40% ammonia when processing the production solution for fertilizer; 15-20 times reduce the number of sludge and fertilizer filtration cycles. All this in a complex allows a significant increase in production.

The complexity of the process of obtaining complex fertilizers.

Claims (4)

1. A method of obtaining a complex acceleration of phosphorus-containing raw materials by decomposing it with dilute hydrochloric acid with a concentration of 1-4%, separating by filtration the production solution from the insoluble residue, followed by processing into fertilizer, characterized in that, in order to increase the productivity of the process by increasing the concentration Pj-og. in the leaching solution and reducing the consumption of hydrochloric acid, decomposition is carried out differentially and each subsequent portion of the raw material and acid are injected until the production solution P has a content of P ,, equal to 15-25%, while maintaining a constant T: M pulp. 2. The method according to claim 1,0 tl and hr and with the fact that the amount of hydrochloric acid in the calsda of the subsequent stage takes less than stoichiometric, taking into account the degree of decomposition of the phosphorus-containing raw material phosphoric acid contained in the production solution from the previous stage . 3. Method according to PP.1I 2, characterized in that the amounts of phosphorus-containing raw materials in each subsequent stage are calculated empirically taking into account the consumption of the liquid phase for its wetting and reduction of the consumption of hydrochloric acid. 4. A method according to claim 1, characterized in that a content of 15-25% in solution is achieved at 15-20 times the production solution. Sources of information taken into account in the examination 1. The patent of Germany No. 1162817, cl. 12 1 25/22, 1968. 2. USSR author's certificate According to the application number 2798597, CL 05 05 11/1 1979.