CS247310B1 - Solid industrial fertilizer on ammonium nitrate base and method of its production - Google Patents

Description

The present invention relates to an ammonium nitrate based fertilizer and to a process for its production.

Ammonium nitrate is the most widely used nitrogen fertilizer in most European countries.

It is easier to use by plants than urea or ammonium sulphate, since most agricultural crops use nitrogen mainly in nitrate form, since the ammonia nitrogen must first be "converted" to a nitrate form before the plants can use it. While the nitrification processes take place quickly in the warm ground, these are very slow in the cold ground (temperatures below +10 ° C). The main disadvantages of ammonium nitrate are:

- NHáNOj is hygroscopic, - NHáNOs is dangerous from the point of view of fire or explosion if the applicable regulations are not observed, - NH4NO3 is reported to be a less suitable source of nitrogen for rice, eye and some other crops requiring enormous amounts of moisture than urea, and nitrogenous fertilizers containing exclusively ammoniacal form of nitrogen, - NITINO is more susceptible to leaching than products containing ammoniacal nitrogen.

In some countries, the sale of the ammonium nitrate base and the form of its ammonium nitrate as fertilizer is prohibited. Production of pure ice is relatively risky, not so much in the production process itself as in other so-called. post-production operations. The high nitrogen content of ammonium is difficult to store and handle because it is explosive. Large ship fires and warehouse explosions forced most countries to stop production.

Likewise, some compound fertilizers containing ammonium nitrate and chloride anions, such as potassium chloride, are dangerous from the point of view of decomposition or, if initiated, can cause so-called "decomposition". cigar smoke. It has been found that the ignition temperature of these products is usually close to 200 ° C, but it can also be substantially lower if the combustion or explosion is initiated by some additives - for example, soft media. The influence of NH4NO3-containing NPK and NK fertilizers on decomposition tendency has been studied by several authors (PERBAL, G .: “The Thermal Stability of Fertilizers Containing Ammonium Nitrate”, Proceedings of the Fertilizer Society, London 1971, No 124; HOUSTON, EC - HOGNETT , TP-DUNN, RR: "Compound Fertilizers from Rock Phosphate, Nitric and Phosporic Acids, and Ammonia," Industrial and Engineering Chemistry, 43 [10]: 2,413 to 2,418). Less than 4% KCl

(about 1.9% Cl) is sufficient to form a mixture susceptible to 'cigarette burning'. This type of degradation is inhibited by ammonium phosphates, and as a result, most NPK fertilizers containing NH4NO3 and KCl are not dangerous.

A very frequent question is: "What is the maximum NH 4 NO 3 content in the fertilizer to make the product explosive and non-flammable?" The answer to this question is not simple and depends on the type and amount of substances present in the fertilizer. The presence of organic impurities and many other conditions are also decisive.

For example, Dutch, governmental institutions have identified the following maximum permissible NH.NO3 levels in blends (Anonym: "FERTILIZER MANUAL", UNIDO - United Nations; New York 1980):

Material mixed Maximum allowable with nitrate NH1NO3 content in ammonium (%)

CaCO3 (chalk) 80 (NH4) 2SO4 40 to 45 (NH4) 2HPOi 65 to 70

CaHPOj 70

KC1 70

K2SO4 70

In general, fertilizers can generally be considered safe from the point of view of the risk of explosion if they contain less than 70% NH1NO3, but do not contain a high content (NH2JSO4 or other reducing substances in the mixture) (SHARP, J.C. Ammonia to Fertilizer Materials ”- Sanchelli Vincent, Ed. Reinhold Publishing Corp., New York 1960, pp. 17-23, 35. Most methods suitable for monitoring the stability of NH4NO3 containing fertilizers are summarized in the manual. "Selected Methods of Testing the Thermal Stability of Coumpound Fertilizers Containing Ammonium Nitrate", first published in 1970 by ISMA and APEA.

In central, western and northern Europe, pure ammonium liqueur is not produced. Ammonium nitrate adds fillers to reduce the nitrogen content of the ice and reduce the risk of fire and explosion.

The most widespread admixture are limestone and dolomitic limestone.

The ingredient prepared by mixing the ammonium nitrate melt with limestones is called ammonium nitrate with limestone (LAV) in Western Europe and overseas "CAN" (calcium ammonium nitrate). In the past, CAN contained 20.5% N, corresponding to approximately 60% NH4NO3, and is currently the most widespread type of CAN containing 26% N (75% NH4NO3) and 28% N (80%

NHíNO3). Ammonium oxide with limestone has good properties not only because the risk of risk has been reduced, but the limestone filler is also a suitable agrochemical fertilizer substance. In our country, depending on the amount of limestone, mainly two types of LAV are produced, containing 25 and 30% N. The low content of admixed limestone, which reduces the total nitrogen content in nitrate to 33 ° / o, is referred to as C -33. For mixing with hot melt NH; NO: finely ground limestone is used (sieve balance 0.15 with 1,600 holes / cm ² 7.4 ° / 0; 0.12 with 2,400 holes / cm ² 0.7%; 0.09 with 4,500 holes / cm ² 1.1%; 0.07 with 6,400 holes / cm ² 4.6%). While stirring, reactions occur to a limited extent, resulting in a partial decomposition of ΝΟ1ΝΟ3 in terms of a considerably simplified cumulative reaction:

NH1NO3 + CaCO3 → Ca (NO3) ₂ + 2N

H; + CO: - | - H.O.

When dolomitic limestones are used for this purpose, magnesium carbonate reacts similarly:

NHiNO 3 + MgCO 3 -> Mg (NO ₃ ) 2 -P 2 N Η. H CO. 110th

In the case of calcined magnesia, resp. trapped dust from magnesia furnaces proceeds with partial decomposition of N H NO.3 according to the following reaction scheme:

MgO + 2NH1NO: Mg (NO3) 2 + 2NH3 + HiO.

Thus, by mixing the ammonium nitrate with the above fillers, ammonia is partially lost from the product. The mixing gases are usually returned to the neutralization stage of the NH 4 NO 3 production process. The resulting alkaline earth nitrates [Ca (NO 3) 2 and Mg (NO 3) 2] also increase the hygroscopicity of the product.

In addition to limestone, dolomites and magnesites, chalk, calcium clay, precipitated calcium carbonate (for example, saturating sludges from sugar production), calcium sulphate (for example from citric acid production or extraction HsPOi) are also used as fillers in NH1NO3 containing fertilizers. and so on.

For safety reasons, the so-called montan ice is produced abroad (mainly in Germany) with a content of about 26% N, which contains one quarter in ice and three quarters in ammoniacal form. It is usually prepared by mixing the melt of NH 1 NO 3 with solid (NH 2 J 2 SO 3) and granulating them.

Bonded or granulated ammonium nitrate or ammonium nitrate with limestone (LAV or CAN) is often

4 7 3 10 'to improve their handling properties, it is also wrapped with various finely powdered materials, which are referred to as "powders" in industrial fertilizer technology.

The following materials are used as curing materials: kaolin, diatomaceous earth diatomite, diatomaceous earth and so-called so-called. Fuller clay. Their content in fertilizers usually varies from 1 to 3 percent. In addition to these additives, some specially stabilizing and physical-handling additive enhancers are sometimes used, including, for example, Mg [NO5] 2, the addition of which inhibits the change of crystalline form of the additive and NH3NO3 and NH3NO3 known as commercially available. label PERMALENE.

It has now been found that solid industrial fertilizers can be prepared based on ammonium nitrate, which are characterized by good physiochemical and handling properties, the use of which is of considerable benefit from an agrochemical, agronomic, pedological and ecological point of view. The essence of the invention is that solid ammonium nitrate based fertilizers contain 24 to 98 percent by weight NH-NO3 and 0.5 to 48 percent by weight hydrated aluminosilicates, in particular of mono- and divalent elements, mainly sodium, potassium, calcium, magnesium and barium , so-called. zeolites, the balance being up to 100 percent water, additives improving the physico-chemical and handling properties of the product, and optionally also ammonium sulfate or other inorganic compounds containing plant nutrients.

It has also been found to be particularly advantageous to use finely ground naturally hydrated aluminosilicates - naturally occurring zeolites which contain the clinoptilolite and / or mordenite and / or chabazite and / or analcem in unactivated or activated form for the preparation of the fertilizer of the invention.

Furthermore, it has been found that solid ammonium nitrate based fertilizers according to the invention can be produced in a manner which consists in that the hot melt containing NH 2 NO 5 is homogenized with hydrated silicate, in particular mono- (K, Na) and divalent (Ca, Mg, Ba) of zeolite elements in such a way that each part by weight of NH 3 NO 6 is from 5. 10 ^-3 to 2 by weight of the zeolite diet. After thorough mixing, the melt mixture is granulated and the granular material thus obtained is optionally still coated with finely dispersed zeolite. The granulometric composition of the zeolite used for surface treatment of the granulate by its impregnation is such that the sieve balance of 0.15 min (with 1600 holes. Cm ² ) is less than 16%. The surface treatment of the zeolite granules is usually carried out in the presence of substances improving the physical-handling properties of the final fertilizer, β

or without the use of other additives of this type.

The use of hydrated aluminosilicate zeolites has a number of significant advantages and advantages over other additives in the production of solid ammonium nitrate fertilizers, including the following:

- the addition of zeolite to the NH1NO3 melt does not cause the decomposition of NH1NO6 and, consequently, the loss of ammonia from the product;

- zeolite, unlike the use of limestone, dolomite and other Mg-substrates, does not increase the hygroscopicity of the product;

- the application of the ion exchange efficiency of zeolites, which is particularly important for vulcanosedimentary zeolite tuffs and tuffs, especially in the case of an ammonium cannon, results in a gradual efficiency of the nitrogenous fertilizer component and reduces its loss by leaching;

- the amelioration effect of zeolites is applied, which is particularly beneficial in acidic and heavy soils;

- due to the high adsorption and hydration capacity of zeolites, its presence in the fertilizer results in an improvement in the water and nutrient management regimes;

- the production of synthetic zeolites is possible on the basis of aluminum production wastes (eg white sludges);

- naturally occurring zeolites (zeolite sulphides and tuffites) contain 35 to 80% of clinoptilolite, which, along with some accompanying mineral waters (mordenite, erionite, chabazite, analcite), bears their unique ion-exchange and sorption properties, are abundant in many countries of the world (USSR, USA, Japan, Bulgaria, Hungary, Yugoslavia, Australia, New Zealand, India, Korea, Cuba, CSSRj;

Naturally the zeolites are relatively mild (hardness 3 to 5, usually 3 to 4).

The following examples illustrate but do not limit the invention in any way.

Example 1

In order to prepare a granulated batch with about 25% total N content per diel part by weight of hot NH: NO melt prepared by neutralizing concentrated nitric acid with ammonia gas containing 97.5% by weight. % NH 2 O, added 26 parts by weight of ground natural zeolite. The ground zeolite used contained approximately 52% clinoptilolite based on ion exchange capacity (KOZAČ, J. et al. 1981) and was obtained by grinding tuffite from a deposit near Nižný Hrabovec. Based on a chemical analysis of clinoptilolite from the above site, it was found that the ground natural zeolite used belonged to K-Ca types with a relative proportion of exchange cations: Ca, K, Na. After thoroughly homogenizing the melt mixture, it was subjected to granulation, the granules thus obtained being powdered during cooling with finely ground natural zeolites of the type mentioned above. Granulometric analysis of the ground zeolite used for blasting revealed that it contained 90% of particles smaller than 50 μΐη. The results of the material balance showed that 98 parts by weight of granulate bound on average 2 parts by weight of natural zeolite.

A granulated zeolite (LAZj) containing an average of 25.2% by weight of total nitrogen was prepared as described above. The treated LAZj was characterized by very good physio-mechanical properties, a high agrochemical-agronomic efficiency and a positive effect on the ground.

Example 2

In order to prepare a modified type of so-called montan ice with the addition of zeolite, a hot melt consisting of 61.3 wt. % (NHi) ₂ SOt, 36.7 wt. % NH 2 CN and 2 wt. % of water homogenized with finely ground natural zeolite from the locality Nižný Hrabovec of type K — Ca. The granulometric composition of the finely ground natural zeolite used was specified by a sieve balance of 150 μπι with 1,600 holes / cm ² , which was equal to 6.8%.

On a 100 weight basis melt, the composition of the above composition was dosed on average

18.2 parts by weight of ground zeolite. By granulating the homogeneous melt mixture, a solid nitrogen-sulfur fertilizer, a modified monanthan ice, was prepared which contained an average of 22 wt. % of total N and 12.5 wt. % assimilable sulfur plants.

Example 3

In order to prepare an ammonium nitrate having a total nitrogen content of 33%, a thermally activated ground K-Ca type zeolite of the Nižný Hrabovec locality was added to the high-concentration hot melt NHíNO3.

The activated zeolite was added in an amount of about 6 parts by weight for each 100 parts by weight of the melt of NH 4 NO 3. NH 4 NO 3 treated in this manner was characterized by low hygroscopicity.

Claims (3)

The mixture was subjected to granulation, and the granules thus obtained were powdered with a finely ground natural zeolite of the type described above during cooling. The granulometric analysis of the milled zeolite used for coating showed that it contained 90% of particles smaller than 50 μΐη. From the results of the material balance, it was found that parts of the natural zeolite were bonded to 98 parts by weight of the granulate by weight. A granular lozenge with a zeolite (LAZ) was prepared as described above and contained 25.2 wt. % of total nitrogen. Said LAZ was characterized by very good mechanical-mechanical properties, high agrochemical-efficacy, and positive influencing of the pod. Example 2 In order to prepare a modified type of zeolite additive hot melt, a hot melt consisting of 61.3 wt. % (NH 3) 2 SO 4, 36.7 wt. % Of NH4Cl2 and 2 wt. % of the water was homogenized with fine-grained natural zeolite from Nižní Hrabovec type K-Ca. The granulometric composition of the finely ground natural zeolite used was determined to be 150 µm with 1,600 holes / cm 2, which was 6.8%. An average of 18.2 parts by weight of milled zeolite was metered in per 100 parts by weight of the melt of the above composition. A solid nitrogen-sulfur fertilizer was prepared by granulation of the homogeneous melt. % total to 12.5 wt. % sulfur-assimilated plants. EXAMPLE 3 In order to prepare ammonium nitrate with a total nitrogen content of 33%, a thermally activated milky natural zeolite K-Ca type from the Nizhny Hrabovec site was added to the high-concentration hot molten NH3 NO3. The activated zeolite was added in 6 parts by weight for each 100 parts by weight of NH 4 NO 3 melt. NH4NO3 thus treated was characterized by low hygroscopicity. OBJECT An ammonium nitrate solid fertilizer characterized in that it comprises: 24 to 98% by weight of nitrate ammonium and 0.5 to 48% by weight of hydrated aluminum silicates, in particular mono- and divalent zeolites, the remainder being 100% they form water, additive-improving the physico-chemical and handling properties of the product or other inorganic compounds containing plant nutrients. 2. A solid fertilizer according to claim 1, wherein the hydrated aluminum silicate comprises a ground natural zeolite which encompasses clinoptilolite and / or mordenite and / or erionite and / or base and / or analcites in non-activated or activated form. 3. A process for producing an industrial ammonium nitrate fertilizer according to claim 1, characterized in that the hot ammonium nitrate melt is homogenized with the hydrated aluminosilicate, in particular mono- and di-zeolites. the weight of NH1NO5 was 5-10-3 parts by weight of zeolite, the melt mixture being granulated after complete mixing and the granulated material was coated with finely dispersed zeolite, without or in the presence of other physico-handling agents product. Severogralia, o. P „závod 7, Most Price 2,40 Kčs