CS272951B1 - Method of triple superphosphate production - Google Patents

Abstract

The invention concerns the method of production of powdered triple superphosphate by decomposition by phosphorous sulphuric acid and extractive hydrogen phosphate. The share of added H2SO4 is 2.30 to 4.98 % and the share of active hydrogen ions of both acids used in the decomposing reaction is 85 to 97.5 % of their stoichiometric requirement. The parameters of the decomposing reaction can also be modified by added water and derivatives of lignosulphonic acid.

Description

(57) The present invention relates to a process for the production of powdered triple superphosphate by decomposition of phosphorous sulfuric acid and extractive trihydrogenphosphoric acid. The proportion of dosed H-SO. it is 2.30 to 4.98% and the proportion of active ion ions of both acids involved in the decomposition reaction is 85 to 97.5 ‘and their stoichiometric need. The decomposition reaction parameters can also be adjusted by the addition of water and lignosulfonic acid derivatives.

and

CS 272 951 Bl

The invention relates to a process for producing triple superphosphate.

In the context of growing agricultural practice requirements for the quality and content of plant nutrients in industrial fertilizers, the production of solid phosphate fertilizers has shifted from simple superphosphate through enriched superphosphate to triple superphosphate. According to existing assumptions, the triple superphosphate will maintain its 20% share among the produced phosphorous fertilizers! and in the future (UNIDO, Fertilizer Manual, Development and Transfer of Technology, Series No. 13, New York, 1980).

One of the aims of the solution in the development of SFT technologies was to use the existing machine-technology equipment as simple as possible, or to make the most of it. enriched superphosphate. Because of the different solidification times of the decomposition sludge and the nature of the reaction mixture at a simple, respectively. enriched superphosphate compared to triple superphosphate, the original three-chamber mixers had to be replaced by a conical high-speed mixer with a three-row mixer with four mixing arms in one row.

Using the addition of surfactants (sulphite liquor), the technology of powdered triple superphosphate production was successfully mastered and implemented at the final level.

Already at the stage of technology development, the possibility of utilizing the known knowledge that the addition of a certain amount of strong mineral acids (sulfuric, nitric, hydrochloric) positively affects the production process in terms of the degree of phosphorus decomposition and the physico-chemical properties of the product and above all which little to use existing mixers used in the production of simple and enriched superphosphate without the need to install special mixers of special design.

This has been fully confirmed in the laboratory and quarter-stage research (Búgel et al., “Trials of triple superphosphate production, Technical Report No. 74, Bratislava 1975),

Using a 10-15% replacement of trihydrogenphosphoric acid with sulfuric acid and a mixed acid equivalent of 95-100% stoichiometrically required, the laboratory and quarter-operation scale produced a product with improved physicochemical properties and a higher conversion rate compared to phosphorous decomposition trihydrogenphosphoric acid alone. Given the possibility of practical application of these results in the production of triple superphosphate on the technological equipment of simple production, respectively. The enriched superphosphate failed to achieve a satisfactory solidification time of the decomposition slurry. For the above process parameters, the solidification times of the slurry were in the range of 2.5 to 15 min. Such times did not guarantee the necessary operational reliability when using conventional malaxers - too short a setting time or when using a high-speed mixer - too long a setting time. The prolongation of the solidification time of the decomposition sludge caused by the addition of sulfuric acid in the ventricular process of the production of triple superphosphate requires adjustments of the mechanical-technological equipment in the technological stage of homogenization of raw materials, respectively split or multi-stage feed of raw materials into the process (Kopylev et al.,

Žur. Ex. chim. 7 1402-1406 (1968), Orechov et al., Agrochimija, 33-35, 1970; Orechov et al., Chim. prom. 671-673, 1970; Sixakov et al., Chim. 5, 670-672 (1972); US Patents 32 33 95; 1,000,443; 1,224,296; “SUPERPHOSPHATE / Its History, Chemistry and Manufacture 'US Department of Agriculture, Dec. 1964).

The phosphite-sulfur decomposition technology is also characterized in that, as the slurry solidification time increases, the fluorine compounds escape in amounts requiring subsequent processing in the absorbent system of the captured hexafluorosilicic acid and the SiO2 gel. Production status would be in CHZ3D, k. p. required significant investment resources to carry out such processing. At solidification times of decomposition sludge in the range of about 20 to 60 s, which corresponds to the current production of SFT, rl

CS 272 951 B1 virtually the entire amount of fluorine remains in the product.

Laboratory verification of published results (Ouhas et al., Chem. Avg. 6, 286 (1978)) confirmed that as the amount of sulfuric acid fed to the decomposition process decreased, the solidification times of the decomposition sludge were gradually reduced and at ca. 2% replacement of H 2 SO 4 with a solidification time equal to the solidification time of SFT slurry prepared without the addition of H ₂ SO ₄ to decomposition. At the same time, however, there is a significant deterioration in the physico-chemical properties of the product, which does not allow the practical use of the SFT production method with H ₂ SO _{4 additions of} less than 10% of the stoichiometric consumption.

It has now been found that the existing machine-technology equipment, so-called. The chamber process allows the production of triple superphosphate in a manner based on efficient homogenization achieved by a high-speed stirrer, ground phosphorous with extractive trihydrogen phosphoric acid in the presence of sulfuric acid. The prepared reaction mixture is then subjected to a decomposition reaction and a crystallization associated with phase changes, the decomposition reaction and crystallization being carried out in a reaction space which rotates about its vertical axis. The solidified decomposition reaction product is continuously removed from the rotating reaction space by mechanical force. The production method is characterized in that the ground phosphorus is homogenized with an extraction HgPO4 containing 47 to 55 wt. % ^P 2 ° 5 ^and sulfuric acid containing 60 to 98 wt. % H ₂ SO ₄ , the acids being metered into the homogenization step individually or in the form of a mixture at a temperature of 15 to 85 ° C. The proportion of active hydrogen ions involved in the decomposition reaction is 85-97.5% compared to the stoichiometric need. Of the total amount of acids, 2.3 to 4.98% of the feed is sulfuric acid and 95.01 to 97.70% of the feed extract is trihydrogenphosphoric acid. Preferably, higher efficiency adds water to the homogenization stage of the process in an amount to adjust the concentration of the commercial extraction agent to 50 to 52% by weight. % P ₂ ° 5 · The contact of the reactants can also be improved by the addition of lignosulfonic acid derivatives.

The advantage of the solution according to the proposed method is that the method is applicable to the existing machinery of the triple superphosphate production plant, while achieving better physico-chemical properties of the product at a lower raw material intensity of production.

The following examples illustrate but do not limit the scope of the invention.

Example 1

A mixture of phosphoric and sulfuric acid heated to 55 ° C in an amount corresponding to the decomposition of 150 g of phosphite of the following composition was charged to a laboratory mixer: 32.16% P ₂ ^{O 5 from} 51.16% CaO, 1.0% H ₂ O, 85% R ₂ 0 g of the particles vePkosti 99.68% of particles smaller than 0.25 mm. 150 g of phosphite were dispensed into the mixer once, the mixture was homogenized for about 5 sec. and the resulting slurry was poured into a 0.75 liter maturing vessel placed in the bath (the temperature of the bath was maintained at 85-2.5 ° C) where the slurry solidified. After 50 min. the solidified product from the aging vessel was mechanically wiped off. The samples were stored in closed polyethylene bags and specified a total content of P ₂ 0 _5, citrorozpustného P ₂ 0 _5, P ₂ 0 _g as the free ΡΟ Η ^ N, the content of H ₂ 0th

All other experiments, the critical characteristics of which are given in Table 1, were carried out in a manner consistent with Example 1.

Example 2

At the SFT production facility, the following quantities of raw materials were fed into the high-speed mixer:

- 15 t / h ground phosphorus containing 51,33% CaO, 32,05% Ρ ₂ θ ₅ and 1,12% H ₂ 0

- 13,61 t / h 72,48% extraction trihydrogenphosphoric acid (expressed as P ₂ 0 _g )

CS 272 951 B1 at 55 ° C.

After 50 min. a product of the following composition was cut from the mating chamber:

content P ^ Og vol '. = 13.57% ”water. = 43.43% 'citro. = 44.36% * tot. = 48.13% H ₂ O content = 11.62%

After three hours of operation, the dosing of raw materials was adjusted as follows:

- 15 t / h ground phosphorus - dosage unchanged

- 10,85 t / h H ₃ P0 ₄ (as P ₂ 0g)

- 0.552 t / h H ₂ SO ₄ - 92.22%

The acids were fed into the process at 55 ° C after mixing in a static mixer. The product carved from the maturation chamber was then composed.

P ₂ content 0 _g vol. ~ 11.17% '' water. - 42,49% citro. »43,74%” “tot. = 46.12% '' H ₂ 0 '= 9.64%

In terms of physical properties, the product was drier, less cuddly.

Example 3

According to the method of the invention, the process equipment of the SFT plant, supplemented with a process line for dispensing H ₂ SO ₄ into the process and a static flow acid mixer, was prepared in the period January-March 1988 during the verification of 8,890 t SFT (as P ₂ ° g). process is documented in Table 2.

Compared to the classical SFT production method, the SFT produced by the above method changed on average as follows:

- conversion to ^ρ 3θ ₅ water increased. 2%

- the H ₂ O content of the product has been reduced and its flowability improved

- the maturing of the product on hunger is accelerated - after about 5 days the content of P is "0 vol". = average 5.5%

- reduced the content of P ₂ 0 _g total. an average of 1.5% on a dry matter basis

- the proportion of P ₂ 0g in the phosphorus-derived product increased from 24,5% to 30%, thus reducing the raw material intensity of production.

Example 4

The SFT produced according to the method of Example 3 was used in the manufacture of granular compound fertilizers. Overall, approximately 48,000 t of GVH III / 5 was produced using the product. Compared to SFT produced in the classical way, GVH increased the content of P ₂ 0g water-soluble (one of the product quality assessment criteria) by an average of 3% and decreased the total nutrient content (N + ^p 2 ° 5 + K ₂ 0) by 0.5 %.

CS 272 951 Bl

Table no. 1

P. no. Percentage of H ₂ SO ₄ from total acidity (%) Conc. ^H 3 ^P0 4 (¾ P ₂ 0 ₅ ) Proportion of acid mixture to stoichiometry (%) Acid mixture temperature (° C) time Pour goo (WITH) Obsah PjOj in the dry product (%) Conversion to citro P ₂ 0 ₅ (after 1-3 days) (%) First 2.30 51.89 95 55 40 50.3 91,64 Second 4.98 51.89 85 40 55 50.1 91.82 Third 3.09 47.05 92.5 30 50 51.1 94.50 4th 3.90 55.0 90.0 85 · 30 50.8 90.51 5th 3.1 51.89 90.0 55 55 52.2 91,20 6th 3.09 52.77 87.5 24 115 51.2 91.80 7th 3.36 52.77 97.5 60 43 51.9 93.63

Table no. 2

P. no. Dosing ^H 3 ^PO 4 (as P ₂ ° 5? T / h Dosing phosphorite (as P ₂ O 3) t / h Dosage h ₂ with ₄ t / h MH Actively H ⁺ ions from ^H 3 ^P0 4 content P ₂ O, SFT H ₂ O content in SFT free ABOUT water. citrate, % tot. % H ⁺ ions zh _{2 s 4} First 11.32 4.34 .4195 15.63 0,840 11.31 43,75 45,73 47.63 11.65 Second 10.54 4.35 .4220 14.55 0,844 9.47 41,87 43.44 46.61 11.37 Third 10.45 4.83 0,510 14.42 1.02 11.03 41,58 42.50 46.44 12.20 4th 11.51 5.08 .5960 15.89 1.19 10.75 40.61 42.48 45.42 10.26 5th 12,12 5.13 .5640 16.75 1.13 10.87 41.75 42.50 45.70 10.70 6th 12.01 5.20 0,620 ' 16.76 1.24 11.17 44,36 44.98 46,72 11,10 7th 11.68 5.28 0,486 16.13 0,970 9.61 40.95 41.75 45.20 10.12 8th 11.52 5.35 0,694 15,907 1.39 11.31 41.74 42.49 44.41 10.76

OBJECT OF THE INVENTION

Claims (3)

CS 272 951 B1 Table 1 P. No. H 2 SO 4 proportion of total acid (%) Conc. h3P ° 4 (¾ P205) Acid content of stoichiometry (%) Temperature of cesium (° C) Curing time (S) PjOj content in dry product (%) Citro P205 conversion (after 1-3 days) ( %) 1. 2.30 51.89 95 55 40 50.3 91.64 2. 4.98 51.89 85 40 55 50.1 91.82 3. 3.09 47.05 92.5 30 50 51.1 94.50 4. 3.90 55.0 90.0 85 · 30 50.8 90.51 5. 3.1 51.89 90.0 55 55 52.2 91.20 6. 3.09 52.77 87.5 24 115 51.2 91.80 7. 3.36 52.77 97.5 60 43 51.9 93.63 Table 2 P. No. DosageH 3 PO 4 (as P2 ° 5 ^ t / h Dosage Phosphorite (as P 2 O 5) t / h Dosage h 2 O 4 t / h MH Activated H + ions of H 3 PO 4 content of P 2 O, SFT content H 2 O in SFT "o" free of water,% total. % H + zh2so4 ions 1. 11.32 4.34 0.4195 15.63 0.840 11.31 43.75 45.73 47.63 11.65 2. 10.54 4.35 0.4220 14.55 0.844 9.47 41.87 43.44 46.61 11.37 3. 10.45 4.83 0.510 14.42 1.02 11.03 41.58 42.50 46.44 12.20 4. 11.51 5.08 0.5960 15.89 1.19 10.75 40.61 42.48 45.42 10.26 5. 12.12 5.13 0.5640 16.75 1.13 10.87 41.75 42.50 45.70 10.70 6. 12.01 5.20 0.620 '16.76 1.24 11.17 44.36 44.98 46.72 11.10 7. 11.68 5.28 0.486 16 , 13 0.970 9.61 40.95 41.75 45.20 10.12 8. 11.52 5.35 0.694 15.907 1.39 11.31 41.74 42.49 44.41 10.76 OBJECT OF THE INVENTION Production Method triple superphosphate based on efficient homogenization of the mixture the phosphorous, the extracting trihydrogenphosphoric acid and the sulfuric acid, subsequent decomposition reaction and crystallization of the prepared mixture accompanied by phase change, wherein the complex reaction and crystallization take place in the reaction space which rotates around the surrounding axis and the solidified reaction product is continuously withdrawn from the reaction space CS 272 951 B1 by mechanical force, characterized in that sulfuric acid is metered in from 2.30 to 4.98% of the total amount of acid and 95.0 to 97.70% of extracted trihydrogenphosphoric acid is metered in and the proportion of active hydrogen ions of both acids participating in the the decomposition reaction is 85 to 97.5% of their stoichiometric need.