CS254029B1 - Granulated multi-component fertilizers and their production methods - Google Patents

Abstract

The solution relates to granular nitrogen-phosphorus fertilizers containing part of the phosphorus component in the form of phosphorite. Other components of fertilizers are ammonium phosphates, ammonium polyphosphates and ammonium sulfate, while the fertilizers may also contain ammonium nitrate, natural zeolite, granulation binder and substances improving their physical and mechanical properties. The above fertilizers are produced by the melt granulation method based on the continuously conducted neutralization of a mixture of trihydrogenphosphoric and sulfuric acids with concentrated ammonia and/or ammonia in ammonium nitrate ammoniates. The product of the neutralization reaction is homogenized with simultaneous formation of granules with returnable material and solid raw materials. The process is characterized in that the granulation is carried out in the presence of phosphorite in an amount of 5 to 60 wt. % of the total P2O5 content in the product. To increase the granulation efficiency, a granulation binder is optionally also added.

Description

234029

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to nitrogen-phosphoric fertilizers and to a process for their production.

Despite the well-known, in particular economic advantages, low cost, the worldwide application of ground phosphites is 5% of the phosphate fertilizers used. material. According to the data from FertilizerManual, Development and Transfer of Technology, Series No. 3 13, UNIDO, New York1980, to obtain good agronomy effect, it is necessary to provide fine phosphorous milligrams such that 90 wt. particles of less than 0.147 mm, or preferably greater than 80% by weight. particles smaller than 0.043 mm. It is generally accepted that the use of such classical ground phosphates is only economically effective on acidic soils with a pH of 6, while the long-term effect of their use is more favorable than their short-term effect. The granulation of ground phosphites has solved the problems associated with the handling and application of fine dusty material, but the product so treated has little aggressive efficacy, since it significantly reduced the contact surface of the ground phosphate with the underlying solution by the granulation process, transforming the ground phosphite into P2O5 accessible to plants. In addition to reducing agronomic efficacy, another advantageous granulated ground phosphite is the difficulty of granulating without the use of a suitable binder, but which complicates the manufacturing process and makes it more costly. Stages Μ. P. Thúring - ZAGRICH, VI. Congress "Chemistry in the Field Economy", June 1984, Bratislava, it is advantageous to carry out the granulation of phosphorous plants, which consists of two working parts - a pre-granulator and a rounding granulator. The advantage of this process is that the fertilizer granules are obtained without any binders, except water and water. A disadvantage is that the granulation process needs to be carried out in two stages. Also, the application of phosphite and activated phosphorous suspensions has not yielded the expected progress in the development of the use of ground phosphites, mainly for some problems related to agronomic efficiency, storage and application. The aforementioned drawbacks of the use of ground phosphites obstruct the invention.

The present invention provides granulated duo-phosphate fertilizers containing 5 to 15 wt. % of total nitrogen which is in ammonia form or in ammonia nitrate form. Fertilizers further contain 18 to 52 wt. % of total P 2 O 5 and characterized in that 5 to 60 wt. %, in the form of ammonium phosphates 35-91.5 wt. % and in the form of condensed ammonium phosphates 3.5 to 53 wt. %.

The fertilizers further comprise 3 to 32 wt. % of ammonium sulphate and possibly also ammonium nitrate, ground natural zeolite as a filler and water and a binder in the form of sulphite liquor or thickened sulphite stillage.

The present invention further provides a process for the production of nitrogen-phosphate fertilizers, which makes it possible to efficiently incorporate phosphorous in the formulation and hence their economic use in agricultural practice. The method comprises the continuous neutralization of a mixture of phosphoric acid trihydric acid and sulfuric acid with concentrated ammonium and / or ammonia in ammonium nitrate ammonia, the product of neutralizing reaction having the character of a melt-vapor-gas mixture being continuously zeroes with solid raw materials and returnable material. The method is characterized in that the phosphorus is added to the fertilizer granules after contact of the melt portion of the reaction product with a phosphorous particles and thus to the formation of granulation nuclei, wherein the weight ratio of P2O5 in the melt and in the phosphite is 0.05 to 1.50.

The phosphorite is preferably a higher agrochemical as well as granulating efficiency by treating it to a particle size of 80% by weight. the particles are smaller than 0.20 mm. The sulphite liquor and / or thickened sulphite stillage is also added to the granulation process for the formulation characterized by a lack of liquid phase.

Said granular fertilizers with their granular composition and their physico-chemical properties ensure good manipulation and uniformity on the stage. An essential advantage of the present invention is the possibility of using phosphates in fertilizers with a pH of > 6 after application of the fertilizer. After the fertilizer is dissolved in the soil, the present acidic components react with fertilizers, in particular SO42- and H2PO4-, preferably in contact with existing ground phosphate particles. to form plant P2O5 forms. By their composition and their phosphorus content in the form of phosphites, ammonium phosphates and ammonium polyphosphate, the granulated sulfur-phosphate fertilizers of the present invention provide high short-term and long-term agronomic efficiency of their phosphorus component for a wide variety of agricultural crops in different soil and climatic conditions, while preserving the economic benefits of using classical ground phosphorates.

In the production of NP granular fertilizers, the addition of ground phosphites, in a suitable manner, to the melt granulation process has a favorable effect on reducing the recycling ratio and thereby improving the economics of their production. For liquid phase deficient formulations for optimal granulation, a binder is preferably added to the process.

Claims (2)

The granular nitrogen-phosphorous fertilizers and the processes for their production are clear but do not limit the invention in the following examples. EXAMPLE 1 The following materials were continuously fed to a model tube reactor as follows: 7.5 kg / h of concentrated gaseous ammonia, 38.5 kg / h of extraction trihydrophosphoric acid containing 53.2 wt. % P2O5, 7.5 kg / h 92.1% sulfuric acid. The neutralization reaction produced in the reactor was sprayed into a model granulator type, in which the following additional feedstocks were simultaneously fed: 25 kg / h phosphorous containing 32.4 wt. % P2O5, 20.5 kg / h ammonium nitrate, 10.0 kg / h ground natural zeolite and 3.0 kg / h sulfite liquor as binder. Granulation gave the product of the following average composition: 13.2 wt. % total nitrogen, 28.2 wt. % total P2O5, 29.0 wt. % of total P2O5 in the form of phosphorite, 4.6 wt. % of total P2O3 in the form of condensed ammonium phosphates, 66.4 wt. % of the total P2O5 content in the ammonium phosphate form, 20.4 wt. % ammonium nitrate, 9.3 wt. % ammonium sulfate. EXAMPLE 2 The following materials were metered in the same manner as in Example 1: 14.5 kg / h of concentrated gaseous ammonia, 82.0 kg / h of extraction H3PO.1 containing 54.2 wt. % P2O5, 12.0 kg / h 93.8% H2SO4, 13.0 kg / h of 32.7 wt. % Of P2O3 granulometric composition, 80% by wt. particles smaller than 0.20 mm. Granulation gave the product of the following average composition: 11.7 wt. % nitrogen, 48.3 wt. % of total P2O3, 8.8 wt. % of total P2O5 as phosphate, 9.8 wt. % of total P2O5 in the form of condensed ammonium phosphates, 81.4 wt. % of the total P2O5 content in the ammonium phosphate form, 15.1 wt. % ammonium sulfate. EXAMPLE 3 The following materials were dosed in the same manner as in Example 1: 11.0 kg / h of concentrated NH3, 23.5 kg / h of 92.1% H2SO4, 26 kg / h of extraction H3PO4 containing 50.3 wt. % P2O5, 45 kg / h phosphorous containing 32.4 wt. % P2O5, 4.0 kg / h thickened sulphite stillage. Granulation according to Example 1 gave the product of the following average composition: 8.7 wt. % total nitrogen, 27.3 wt. % Of total P2O5, 53.0 wt. % of total P2O5 in the form of phosphorite, 26.3 wt. % of the total P2O5 content in the form of condensed ammonium phosphates, 20.7 wt. % of the total P2O5 content in the ammonium phosphate form, 29.1 wt. % ammonium sulfate. OBJECT 1. Granulated nitrogen-phosphate manure containing 5 to 15 wt. % total acetic acid, 18 to 52 wt. % of total P 2 O 5, characterized in that 5 to 60 wt. In the form of ammonium phosphates 35 to 91.5 wt. %, in the form of condensed ammonium phosphates from 3.5 to 53 wt. %, further comprising 3 to 32 wt. % ammonium sulfate and / or ammonium nitrate, ground natural zeolite, water and a binder in the form of a sulphate liquor and / or thickened sulphite stillage. 2. A process for producing granular nitrogen-phosphoric fertilizers of the general composition of the invention according to claim 1, based on the continuous neutralization of the trihydrogenphosphoric and sulfuric acid mixtures with concentrated ammonia and / or nitrate ammonium ammonia, the product of the neutralizing reaction having a melt-steam character. gaseous mixture is continuously granulated with solid raw materials and recoverable material, characterized in that the incorporation of phosphite into fertilizer granules occurs after contacting the melt portion of the reaction product with the neutralization reaction with phosphorous particles to form granulation germs, wherein the weight ratio of P2O5 in the melt and iron> the phosphorite is 0.05 to 1.50.