SU1546457A1 - Method of producing coatings for fertilizer protection - Google Patents

Abstract

The invention relates to the production of mineral fertilizers and can be used in the chemical industry to produce slow-acting fertilizers. The aim of the invention is to increase the content of slow-acting forms of nutrients and to increase the mechanical properties of the coating. The goal is achieved by the method of obtaining a coating for the protection of fertilizers containing phosphates and / or calcium and / or magnesium sulfates, by reacting an aqueous solution of ammonium polyphosphate with desfluorinated phosphate at a ratio, wt.%: Defluorinated phosphate 84-92

ammonium polyphosphate 8-16. In this case, an aqueous solution of ammonium polyphosphate is used with 27.5-58% of the basic substance. 1 tab.

Description

The invention relates to the production of mineral fertilizers and can be used in the chemical industry for the production of slow-acting granulated fertilizers.

The purpose of the invention is to increase the content of slow-acting forms of nutrients and increase the mechanical properties of the coating.

Examples of the implementation of the coating.

Example 1. Preparation of coating composition, wt%: a filler (crushed defluorinated phosphate) 89, a binder (ammonium polyphosphate PFA solution) 11.

Take 100 g of defluorinated phosphate obtained by hydrothermal processing of apatite containing 41%

R405 SR, 51.8% CaO, 3.2% MgO and 12.5 g of a 56.0% ammonium polyphosphate solution with a content of 34.1%., 10.1% N, 4% MgO, 0.5 % S03.

The coating is applied to nitroammofoski granules with a size of 3-4 mm in a working dish granulator with. 0.4 m in diameter. In the granulator, the binding agent is sprayed onto the granules through a nozzle at the same time and rolled in a filler, which is continuously fed into the apparatus.

Part of the granules are removed when a coating of 0.5 mm in thickness is formed on them, and some with a layer thickness of 1 mm.

The obtained granules are dried in a drying cabinet at t 100 C for 40 minutes. The strength of the obtained poksd

4. About SD

dig 6.0 mPa. The coating contains substances in its composition, 7 ,: P, 0

sr

41.3; N 0.85; MgO 3.15: CaO 46.1.

The time of mechanical destruction of the coating deposited on the granules, when exposed to 0.02 n. The CaCl7 solution is at a coating thickness of 0.5 mm, 175 minutes, at a coating thickness of 1 mm, 300 minutes.

g. Options for obtaining the proposed composition and prototype are given in the table.

As can be seen from the table, the proposed composition of the coating compared with the prototype contains a higher concentration of slowly soluble nutrients, and its strength is higher.

The physical properties of the coating are such that it can be applied in a semi-dry way to some types of granular water-soluble fertilizers, significantly slowing their destruction under the influence of moisture.

The composition of the coating is not hygroscopic; the granulated fertilizers coated with it are not compacted.

In addition, the advantages of the proposed coating composition in comparison with the prototype are the rejection of the use of acidic binders, which are highly aggressive substances, which requires expensive equipment and complicates the work of the staff, as well as reducing the energy consumption of the coating process, as it however,

0 5

0

five

environment does not require heating of the components, as well as the fact that fertilizers covered with such a composition provide the opportunity for bulk transportation and storage, significantly reducing their cost by eliminating the taring operation and increasing labor productivity in transport and folding.

Claims (2)

1. A method for producing a coating for protecting fertilizers containing calcium phosphates and / or sulfates and / or magnesium by reacting a binder ic filler on the surface of fertilizer granules and subsequent drying, which is characterized in that, in order to increase the content of slow-acting forms of nutrients and increase its mechanical properties, an aqueous solution of ammonium polyphosphate is used as a binder, and defluorine is used as a filler phosphate in the following ratio, wt.%: Defluorinated phosphate. 84-92 Polyphosphate ammonium 8-16 I 2. A method according to claim 2, in which an aqueous solution of ammonium polyphosphate is used with 27.5-58% of the basic substance. 94 OF 6 PFA 56 2.5 41.18  80 OF 20 PFA 56 84 OF 16 PFA 27.5 84 OF 16 PFA 58 8 Nitroam-84 OB 16 PFA mofoska 9 - 84 OF 16 PFA 56 2.5 41.18 56 27.5 58 3.0 41.30 30 120 2, o, 41.41 30 45 20 1.7 41.05 10 17 65.0 - 1.6 40.60 11 18 The content of OF is greater than the upper limit. Content OF less than the lower limit PFA concentration lower limit PFA concentration c. binder meets upper limit The concentration of PFA in the binder is less than the lower limit The concentration of PFA in the binder is greater than the upper limit by myself Semi-dry coating forms poorly Due to the high content of the liquid phase, a semi-dry coating does not form. The conditions of uniform averaging of raw materials are violated, low resistance of the coating to destruction Low strength and short time of destruction of the coating Low strength and short time of destruction of the coating Note. OF- defluorinated phosphate; PFA - ammonium polyphosphate; AFP - ammofoska pulp