CS257373B1 - A method of producing a melt of condensed ammonium phosphates - Google Patents

Abstract

The solution concerns the method of producing a melt of condensed ammonium phosphates produced by high-temperature neutralization of phosiouric acid with ammonia. The hot product of the reaction of phosphoric acid with phosphorus oxides formed during the burning of elemental phosphorus is subjected to continuous] high-temperature] neutralization with ammonia. For each mass part of phosphorous oxide dosed into the process in the form of phosphoric acid, 0.02 to 0.80 mass parts of elemental phosphorus and 0.14 to 0.44 mass parts of ammonia are dosed into the reaction.

Description

257373 3

BACKGROUND OF THE INVENTION The present invention relates to a process for the production of melt-condensed phosphates by ammonium, high-temperature neutralization and dehydration of phosphoric acid, or solutions of ammonium phosphates in phosphoric acid, with gaseous ammonia.

A melt of polycondensed ammonium phosphates of the formula (NH4) mH (n + 2) -mPnOjn + 1 is one of the base bases for the preparation of concentrated multi-component clear and suspension liquid fertilizers, detergents, thickeners, retarders Nowadays, a number of methods for the preparation of polycondensed ammonium phosphate are known, and the most widely used are the atmospheric pressure or vacuum neutralization of polyphosphoric superphosphoric acids with ammonia. or the basis of which is the reaction of the hydrogen phosphoric acid with varying concentration and purity with concentrated ammonium.

Conventional production processes are based on the non-neutralization of the polyphosphoric (superficial) acid (Hn + 2PnO3n + i) with ammonia. For example, according to U.S. Pat. No. 3,484,192, 3,537,814, 3,572,990.3,645,674, 3,687,618, 3,544,298, 3,676,101, 3,734,708, 3,775,534, 3,939,255, 3,947,261, 3,950,495, and 4,011,300.

Although, for the first time in industrial scale, the condensed ammonium phosphate melt (KFA) was prepared on an industrial scale in 1957 in WEST KEN-TACKY LIQUID FERTILIZER COMPANY in Hopkinsville ( USA), the vast majority of manufacturers of so-called basic nitrogen-phosphate liquid polyphosphate liquid fertilizers still use processes for the preparation of processes based on the neutralization of polyphosphoric, so-called super-phosphoric acid by ammonia water or ammonia gas . The process for the production of KFA by neutralization of polyphosphoric acid and monoacids can be simplified as follows: Stage 1 - preparation of polyphosphoric, so-called suiperphosphoric acid by thermal dehydration of trihydrogenphosphoric acid t η H3PO4 ---- ► 2nd stage - polyphosphoric acid neutralization

Hn + 2P 'O3n + 1 + m NH3 ----> (NH4) mH (n + 2) -ηιΡηθ3η +1 or H' + 2PnO3n + 1 + m (NH3.H2O) ---- * (NH4) mH (n + 2) -ιηΡηθ3η + 1 4 "mH 2 O. At present, about 70 US-produced, 7 large-capacity units in the USSR and at least 4 plants in France produce 10–34–0 type fertilizer. From the superfossic acid prepared by the foam-concentrating purified H3PO4 produced by the so-called wet process - extraction H3PO4, high-temperature non-neutralization and simultaneous dehydration of trihydrogenphosphoric acid are the basis for more modern and, in particular, expanding manufacturing processes of polycondensed ammonium phosphate. acids (H3PO1) with concentrated ammonia.

Simultaneous neutralization and molecular dehydration of the reaction mixture can be represented by the reaction scheme: η H 3 PO 4 + m NH 3 -> (NH 4) m H (n + 2) m PnO 3 n + 1 + (n-1) 1 O 10. For example, a number of inventions relating to the subject matter can be cited as follows: U.S. Pat. No. 3,382,059, 3,375,063.3,420,624, 3,464,808, 3,723,086, 3,503,706, 3,649,175, 3,650,727, 3,788,817, 3,554,728, 3,562,778, 3,677,734, Nos. 3,733,191, 3,949,058, 4,041,133, 3,540,874, 3,446,581, 3,492,087, 3,539,327, 3,502,441, 3,917,475, 3,988,140, and 4,104,362, French Pat. No. 1 493 803 a 2 009 787, MS. Authentic Certificates No. 180 802,199 819, 205,849, 210,335 and 216,856. Although both types of process allow for the preparation of a melt of poly-condensate phosphates of ammonium, industrial applications are usually complicated mainly due to some of these disadvantages: - first-type processes are energy-intensive and their use requires the use of special construction materials as well as special and investment-expensive machinery and equipment; - the technology underlying trihydrogenphosphoric acid treatment usually does not provide products of such quality as those based on polyphosphoric, superphosphoric processing

Hn + 2PnO3n + i + (n - 1) H2O 237373 acids and often also do not guarantee the same level of operational certainty. Over the past period, molecular dehydrates of ammonium phosphates have been studied in the presence of urea, or thiourea, which functions as a condensing agent. Processes of this type include, for example, the following inventions:

USSR Certification No. 420602 (1974), NSC Patent Nos. 2,308,408 (1974), 1,925,068, (1969), 1,228,593, (1963), DAS No. 1,198,335; Japanese Patent Nos. 47-303,333 (1972), 39,960 (1969), 46-37,664 (1974), French Patent Nos. 1,533,272 (1968), 1,461,027 (1966), 1,471,510 (1967) , 1,437,486 (1966), U.S. Pat. No. 3,397,035 (1968), 3,586,495 (1971), 3,495,937 (1970), 3,419,349 (1968); Belgian Patent Nos. 674 161 (1966), 677 866 (1966) and British Patent No. 1,182,395 (1970).

Processes underlying the dehydration ability of sulfur oxides, or product polymerization or hydration reactions, respectively. combinations of their use with urea or thiourea are the subject of MS. Certificate No. 237 462a 249 214.

It has now been found that the melt of condensed ammonium phosphates can be produced according to the proposed solution. SUMMARY OF THE INVENTION The present invention provides a process for the production of a condensed phosphate salt of ammonium formed by the high temperature non-precipitation of extraction phosphoric acid, or mixtures thereof with thermal phosphoric acid ammonia. The process is characterized in that a continuous high temperature neutralization with ammonia, with simultaneous dehydration of the reaction mixture, is subjected to a hot reaction product of phosphoric acid with phosphorus oxides formed during the combustion of elemental phosphorus. In each case, 0.02 to 0.80 parts by weight of elemental phosphorus and 0.24 to 0.44 parts by weight of elemental phosphorus are metered into each part by weight of phosphorous oxide fed in the form of extractive phosphoric acid, or a mixture thereof, with phosphoric acid. ammonia. In particular, the preferred method for producing molten condensed ammonium phosphates compared to prior art processes is that the reaction heat released by the phosphorus (Qi) combustion and the hydration of the resulting phosphorus pentoxide (Q2) is used economically. According to the data of B. P. Melnik, Inžinernyj spravočnik after technology of nonorganic cultures, Izd. Chimija, Moscow 1975 is Qi = 24,310 kj / kg phosphorus and Q2 = 3,274 kj / kg phosphorus. Said advantage results in an increase in the raw material intensity of production or in the improvement of the quality of the products produced by the condensed ammonium phosphates.

The following examples illustrate, but are not limited to, the method for producing ammonium condensed phosphate melt. Example 1

An average of 60 g / min-extraction trihydrogenphosphoric acid containing 52.04% P2O3 at a temperature of about 20 [deg.] C. was introduced into the model laboratory tube reactor with an average of 2.16 g / min molten white phosphorus at a temperature of 75 to 80 [deg.] C., about 1.2 times the excess air in comparison with with a stoichiometry of the equation P1-j-5 O2 - * 2 P2O1, in the reactor, the vapor-liquid mixture at 142-167 ° C was neutralized with gaseous ammonia, which was fed into the reactor at an average of 123.5 g / min. At a temperature of 228 to 242.5 ° C, the following composition is formed: total P2O5 content - 62.32% total N - 11.92%

P2O5 content in condensed form - 59.8% of total P2O5. Example 2

An average of 36 g / min of extraction H3PO4 containing 52.04% P2O3, an average of 22 g / min of thermal H5PO1 containing 56.88% P2O5, an average of 138 g / min on average 138 g / min of average H5PO1 containing 56.88% P2O5, averaged 138 g / min. g / minH 2 O, on average 24.5 g of molten white phosphorus at a temperature of 75 to 80 ° C and an average of 0.16 m 3 / ml of air. The heat-treated steam-liquid mixture at 158-173 ° C was neutralized with gaseous ammonia dosed at 14.8 g / min. At a temperature of 259 to 288 ° C, the resulting melt had the following composition: total P2O5 content - 64.08% total N - 11.88% P2O5 content in condensed form - 68.1%

The processin prepared by the above process was used (by dissolving in H2O for the preparation of NH3) to prepare a liquid fertilizer of the type 10-34-0 of the following composition: total content of N - 10.18% total content of P2O5 - 34.35% share of P2O5 in condensed form - 62.0% pH (1% aqueous solution) - 6.42 specific gravity - 1.41 g / cm 3

Claims (1)

Process for producing a melt of condensed ammonium phosphates formed by high temperature neutralization of extractive phosphoric acid, or a mixture thereof with thermal phosphoric acid ammonia, characterized in that the continuous high-temperature ammonia neutralization under simultaneous dehydration of the reaction mixture with the phosphoric acid reaction , which arise from the burning of elemental phosphorus, for each part by weight of phosphorus pentoxide fed into the process in the form of extractive phosphoric acid or a mixture thereof with thermal phosphoric acid, 0.02 to 0.80 parts by weight of elemental phosphorus and 0.24 are added to the reaction. up to 0.44 parts by weight of ammonia.