CS259372B1 - Process of continuous production of polycondensed ammonium phosphate melt - Google Patents

Abstract

The subject of the invention is a method for the continuous production of a melt of polycondensed ammonium phosphates by simultaneous high-temperature neutralization and dehydration of phosphoric acid, or solutions of acid ammonium phosphates in phosphoric acid with gaseous ammonia.

Description

SOCIALIST REPUBLIC OF CZECHOSLOVAKIA (19Ϊ DESCRIPTION COMPLETED WITH COPYRIGHT CERTIFICATE! 259372 (11) (Bij f lésw (22) Entries 27 12 85 (21) (PV 9919-85) (51) Int CL4 C 01 B 25/23 C 01 B 25/38 (5¾ (40) Published 15 03 88 ÚADAD FOR INVENTIONS AND DISCOVERIES (45) Published 15 03 89 (75)

Author of the invention TEREN JÁN ing. CSc., HUTÁR EDUARD ing., GABČO MILAN ing. CSc., LEXA VLADIMÍR JUDr. Ing. CSc., HARMANIAK IVAN ing., BRATISLAVA, HEGNER PAVEL ing. CSc., ÚSTÍ nad Labem, CHROMIC CAROL ing., PEZINOK, SERIOUS EMIL, BRATISLAVA (54) Method of continuous production of polycondensed phosphate-melt 1

SUMMARY OF THE INVENTION The present invention provides a process for the continuous production of polycondensed ammonium phosphate melt by simultaneous high temperature neutralization by the addition of phosphoric acid and ammonium phosphate acid phosphates with ammonium phosphate.

The melt of polycondensed ammonium phosphates of the formula (NH4) mH <n + 2> mPnO3n + 1 is one of the basic starting materials for the preparation of concentrated multi-component clear and suspension liquid fertilizers, detergents, thickeners, flame retardants, corrosion inhibitors and also some additives used in the context of the textile refinement. Several methods for preparing polycondensed ammonium phosphate melt are now known. The most sophisticated and widespread methods are those which are atmospheric, pressurized, or vacuum neutralizing polyphosphoric superphosphoric acids with ammonia or by means of which the reaction of tri-hydrogen phosphoric acid with a high concentration and concentration with concentrated ammonium is the reaction.

Conventional methods of production are based on the non-neutralization of polyphosphoric superfossic acid (Hn + 2PnO3n + i) with ammonia. For example, a number of modified methods of this kind can be mentioned in U.S. Pat. No. 3,484,192, 3,537,814,33. 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. \ t Nowadays, in the preparation of nitrogen-phosphorous liquid fertilizers of polyphosphate type, the processes based on the neutralization of polyphosphoric so-called superphosphoric acid with ammonia water or ammonia gas are still used.

The process of producing KFA by neutralizing polyphosphoric acid with ammonia can be simplified as follows: 1st stage - preparation of polyphosphoric superphosphoric acid by thermal dehydration of trihydrogenphosphoric acid 259372 2S9372 t η H3PO4-- · - »Ηη + 2Ρηθ3η + 1 + (η — 1) Ο2Ο 4 2nd stage - neutralization of polyphosphoric acid

Hn + žPnOan + l + Π1 NHg --- ► (NH ^ mH (n + 2) -ιηΡηθ3η + 1 or Ηη + 2Ρηθ3η + ι + Π1 (NH3. H2O) --- ► (NH4) mH (n + 2 ) -mPnO3n + l + Π1 H20 High-temperature non-hardening and simultaneous running of H3PO4 + m NH3 --- ► is the basis of more modern and mainly expanding production processes of polycondensed ammonium phosphate melt.

Although both types of process enable melt production of poly-condensed ammonium phosphates, industrial applications are usually complicated mainly due to some of these disadvantages: - first-type processes are energy-intensive and require the use of special constructional 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 the processing of so-called superphosphoric polyphosphoric acid and often also do not guarantee the same level of operational certainty. More recently, molecular dehydrates of ammonium phosphates in the presence of urea, or thioureas, which function as a condensing agent, have been studied in the past. Processes of this type include, for example: U.S. Pat. No. 4,860,602. The processes underlying the dehydration ability of sulfur oxides or products of their polymerization or hydration reactions, respectively. combinations of their use with urea or thiourea are the subject of MS. Certificate No. 237 462.

It has been found that the disadvantages of these two types of polycondensed phosphate-ammonium technology processes are avoided by the present invention.

A method for continuously producing the melt of polycondensed ammonium phosphates by hydrating trihydrogen phosphate (H3PO4) with concentrated ammonia.

Simultaneously proceeding neutralization and molecular molecular dehydration of the reaction can be represented by the reaction scheme:

(NH 4 HH (n + 2) -mPnO 3n + 1 + (Π + 1) H 2 O simultaneously guided by high-temperature neutralization and dehydration of phosphoric acids at a temperature of 10 to 280 ° C, which contains 56 to 66% by weight of P2O 5, but acidic solutions ammonium phosphates with phosphoric acids with ammonium gas without or in the presence of urea and / or thiourea and / or sulfur dioxide and / or in the presence of sulfur trioxide reaction products, a temperature of 185 to 420 ° C is based on that phosphoric acid entering the reaction medium is obtained by homogenizing tri-hydrogen phosphoric acid - H3PO4 containing 28 to 55% by weight of P2O5 and polyphosphoric acid - Hn + 2PnO3n + 1, the number of phosphorus atoms in the n molecule being no more than 5, containing 67 to Preferably, the homogenization is effected by continuously contacting the two components just prior to the introduction of such a mixed acid into the reaction medium or the environment in which the high temperature neutralization and dehydrogenation occur simultaneously, the trihydrogenphosphoric acid - H3PO4 and the polyphosphoric acid - Ηη + 2Ρηθ3η + ι separate. The proportion of acid-inducted to the reaction medium is also that 1.086 to 93.304% of the total phosphorus content of the reaction medium comes from phosphoric acid-H 3 PO 4a and 6.969 to 98.914% of the total phosphorus content of the reaction medium comes from polyphosphoric acid - Hn. + 3PnO3n + i.

The process for preparing the melt of polycondensed ammonium phosphates according to the present invention allows the production of high-quality melts by simultaneous high-temperature neutralization and dehydration and dehydration without the need to supply the reaction system from the outside to the reaction system.

The preparation of the melt of the polycondensated ammonium phosphates of this dependent invention is documented and clarified, but in no way limit the following examples. EXAMPLE 1 In order to provide a quarter-run verification of the continuous melt production process of condensed ammonium phosphates, the MS stage is converted into a vertical process reactor. Certificate No. 210 335 continuously dosed with an average of 6.639 g. s_1 extraction H3PO4tzv. black type, containing 51.7 wt. total P2O5, 8.527 g. with a polyphosphoric acid of the green type containing 70.5 wt. % of total P2O5 and 3.480grams. s_1 NH3 gas. The 93 ° C tri-hydrogen phosphoric acid and the 65 ° C superphosphoric acid polyphosphoric acid were continuously mixed in a short packed column immediately before the mixed acid was introduced into the bubbling reactor. The polyphosphoric acid fed into the upper portion of the used filler homogenizer while the processed trihydrogenphosphoric acid is pumped into its bottom portion - below the filler layer.

A continuously prepared phosphoric acid mixture containing an average of 62.26 wt. The% total P 2 O 5 is fed to the portion of the bubbling reactor used, where it concentrated with concentrated gaseous ammonia fed through the reactor through a tube inlet, passing through the reactor top down and terminated gently above the reactor bottom by a. The processed polyphosphoric acid contained about 29 wt. % biphasic] so-called pyrophosphoric acid (n-2). As a result of the exothermic neutralization reaction of the dosed phosphoric acid / ammonia mixture, in addition to the evaporation of the free water, dosed into the reaction medium with a mixture of phosphoric acids, also for molecular dehydration of the phosphates. The product of simultaneous high-temperature neutralization and dehydration was a heavily foamed melt temperature of 260 ° C, which continuously exited the bubbling reactor through an overflow located in its upper portion. Under these conditions, an average of 55.96 kg of polycondensed ammonium phosphate was obtained, which contained 56.5% of the phosphorus bound in the form of condensed phosphates. The prepared melt was continuously processed into a liquid NP-fertilizer. EXAMPLE 2 In the interest of continuous preparation of melt-polycondensed ammonium phosphates, an average of 179.28 g was metered into a vertical bubbler reactor made of impregnated graphite GRAFODUR. with "1 mixed] acid prepared by continuous stirring of 108.23 g. tri-hydrogen phosphate extract acid (H 3 PO 4) containing 53 wt. % of total P2O5; with 45.08 g. with &quot; 1 polyphosphoric &quot; sapphosphoric acid, prepared by thermal dehydration of extraction H3PO4 containing 70% by weight of total P2O5 (Hn + 2PnO3n + i) and 25.97 g. s-1 sulfuric acid contact] containing 98 wt. % MH-H2SO4. An average of 46.18 g of ammonia gas was metered into the reactor through an inlet tube at the bottom of the bubbling reactor.

An average of 225.46 g was obtained by neutralizing-dehydrating the autothermal chemical reaction of a batch of mixed acid at 96 ° C with gaseous ammonia, a preheated passage through the feed pipe heated from the outside of the reaction mixture. with a &quot; 1 paro-melt] reaction mixture of 278 ° C, which consisted of 78.1 wt. % of the molten liquid phase. % superheated water vapor and 0.1 wt. % of inert and fluorine offgas. Finally, the relatively high vapor-gas phase in the reaction mixture is overheated to the above-mentioned temperature (278 ° C), and the neutralization-dehydration reaction was accomplished under extremely intense mixing. reaction mixtures.

Chemical analysis of solidified samples showed that it contained 12.7 + 1.5 wt. % N; 50.5 +1.0 wt. % of total P2O5 and 6.0 + 0.5 wt. % total sulfur. The melt prepared by the above process contained 56 +2% phosphorus bound form of condensed phosphates, whereby the chromatographic analysis of 11a cellulose thin films determined that the melt samples contained a maximum condensation degree of phosphorus n = 4 to 5. The prepared ammonium condensate melt was continuously further processing the liquid NPS-fertilizer with plants of good assimilable sulfur.

Claims (1)

SUBJECT Process for continuous melt production of polysensated ammonium phosphates by simultaneous high temperature neutralization and dehydration of phosphoric acids at a temperature of 10 to 280 ° C containing 56 to 66% by weight of P2O5, or solutions of acidic ammonium phosphates in phosphoric acids, with or without ammonia in the presence and / or thiourea and / or sulfur trioxide and / or in the presence of hydration reaction products of sulfur trioxide at a temperature of 185 to 420 ° C, characterized in that the phosphoric acid entering the reaction medium is obtained by homogenizing trihydrogenphosphoric acid containing 28-55 wt. % Of P2O5 and polyphosphoric acid H _n + ₂ P _n O 3 _n + _i, wherein the number of phosphorus atoms in the molecule n is equal to a maximum of 5, containing 67 to 75% by weight of feathers. P2O5, wherein the homogenization is preferably carried out by continuous contact of the two components just before the mixed acid thus prepared enters the reaction medium or into a medium in which simultaneous high-temperature neutralization and dehydration occurs, trihydrogenphosphoric acid and polyphosphoric acid H _{n +} 2PnO ₃ n + i 3 The proportion of acids fed to the reaction medium is such that 1086 to 93,304% of the total phosphorus content of the reaction medium comes from trihydrogenphosphoric acid and from 6,696 to 98,914% of the total phosphorus content of the reaction medium comes from polyphosphoric acid H _{n +} 2PnO _{3n +} i · Severography, n. p. Race 7, Most Price 2,40 Kčs