RU2279417C1 - Method of production of granulated phosphate fertilizer containing humate - Google Patents

Abstract

FIELD: production of granulated mineral fertilizers containing humate of alkaline metals; granulated phosphate fertilizers in particular, such as ammophos, diammonium and super-phosphate.

SUBSTANCE: proposed method includes preparation of granules containing ammophos, for example or diammonium or super-phosphate and humate of alkaline metal. Granulation is performed in drum-type apparatus by spraying pulp of phosphorus-containing fertilizer at moisture content of 8-15% onto recycled particles mixed preliminarily with loose humate of alkaline metal at size of particles not exceeding 0.15 mm. Humate is preliminarily mixed with recycled particles in separate reservoir or on conveyer feeding the recycled particles to granulation apparatus or directly in granulation apparatus.

EFFECT: improved agro-chemical properties of product.

4 cl, 1 tbl, 1 ex

Description

The invention relates to the production of granular mineral fertilizers containing humates of alkali metals, namely, granular phosphorus fertilizers, such as ammophos, diammonium phosphate, superphosphate and others. Such fertilizers can be used in agriculture for any soil and are especially useful in conditions of adverse environmental influences (drought, soil salinization, etc.).

It is widely known that humic compounds (humates) are used in the preparation of complex fertilizers, since they can increase the biological activity of the latter and, accordingly, increase agrochemical efficiency. At the same time, methods have been developed for the various introduction of humates in the production process of granular mineral fertilizers.

So, for example, a method is known for producing complex fertilizer, including the manufacture of granules from mineral fertilizers and alkali metal humate. Mineral fertilizer (for example, ammophos, diammonium phosphate, nitrophoska) is preheated to its melting point, after which an alkali metal humate is introduced into it in the form of an aqueous solution in the amount of 0.15-1.0 wt.% By active substance, and then the melt is granulated in a vertical column in suspension while blowing with cold air (RF Patent No. 2184103, class C 05 G 1/00, 2002).

However, this method is very energy intensive and technologically complicated and therefore completely inapplicable in the large-tonnage existing production of granular phosphorus fertilizers.

The most common methods for producing complex mineral fertilizers in shells from humic preparations.

A known method of producing mineral fertilizers, including phosphorus-containing, in a humate shell, in which the mineral base of the fertilizer is sprayed with a humic preparation, for example, an aqueous solution of potassium humate (G. Pirogovskaya and others. Use of humic preparations in the production of mineral fertilizers. Sat. Humic Substances in the Biosphere. - M .: Nauka, 1993, p.166-168).

However, the product requires additional drying, and the film of humates during the storage, transportation and fertilizing in the soil exfoliates from the granules.

The known method, we have chosen as a prototype, aims to eliminate this drawback. According to this method, a fertilizer-based mineral base in the form of granules 1-3 mm in size is treated with powdered humate of potassium with a moisture content of 12% when they are mixed together in a rotating drum. Then, fertilizer granules plated with a humate coating are sprayed with vigorous stirring with a 10% aqueous solution of potassium humate with the addition of urea-formaldehyde resin, enveloping the primary humate coating with a second layer. Humated fertilizer is dried and served for packaging (RF Patent No. 2110503, C 05 C 9/02, 1998).

This method partially eliminates the disadvantage of other known methods, but it requires increased energy consumption for additional drying of the moistened granules and the use of additional film-forming substances. In addition, applying a polymer film dramatically reduces the initial solubility of fertilizers, i.e. complicates the initial release of phosphorus into the soil, thereby not providing optimal conditions for the interaction of humates with soil solution. Particularly great difficulties arise when trying to introduce humic compounds by known methods (i.e., applying a film to granules) in existing multi-ton production of complex phosphorus-containing fertilizers using drum granulators.

The objective of the present invention is to eliminate the above disadvantages, i.e. improving the physical and agrochemical properties of the obtained fertilizers while simplifying the process flow diagram.

The problem is solved in the proposed method for the production of granular phosphate fertilizer containing humate, including the manufacture of granules containing phosphorus-containing mineral fertilizer, alkali metal humate, in which the granulation process is carried out in drum-type apparatuses by spraying phosphorus-containing pulp with a moisture content of 8-15% on retour, pre-mixed with dry alkali metal humate with a particle size of not more than 0.15 mm.

In this case, the retur with humate is either pre-mixed in a separate container, or on a conveyor feeding the retur to the granulation apparatus, or directly in the granulation apparatus, but before the phosphate pulp is sprayed onto the granules.

The alkali metal humate is introduced in an amount that provides the ratio: alkali metal humate: P ₂ O ₅ in the product, equal to 0.006-0.015: 1. As a phosphorus-containing pulp, a pulp containing ammophos, or diammonium phosphate, or superphosphate is used.

The essence of the method is as follows. Humate alkali metal with a certain particle size when mixing is layered on larger particles of retura. As you know, retur is a small finished product, which, after the main product is withdrawn from the process, returns to the granulation stage. Retur consists of granules from 1 to 3 mm in size, having a rough surface. Loose humate of an alkali metal with a particle size of not more than 0.15 mm is mixed with these granules. In this case, the retur particles, as it were, are covered with a humate film that does not collapse until it is coated with a phosphate-containing film. After drying, humate is inside the granule, which improves the physical and agrochemical properties of fertilizers. Unlike known methods, the outer coating consists of phosphorus-containing fertilizer. It is non-hygroscopic, which reduces the caking of the fertilizer and, dissolving in the soil, promotes the formation of complexes, which then interact with humates, preventing their leaching from the soil. The process of film strengthening largely depends on the moisture content of the pulp being sprayed. Humidity of the pulp varies in the range of 8-15%. At a moisture content of less than 8%, the adhesion properties of the pulp are small and it is impossible to obtain products of the required quality, and at a moisture content of more than 15% the pulp does not have time to dry quickly and is mixed with humate, which affects the agrochemical properties of the product.

The method is illustrated by the following examples.

Example 1. 1000 kg / h of ammophos pulp with a moisture content of 12%, obtained by neutralizing extraction phosphoric acid with ammonia, is sprayed into a BGS apparatus, where 1000 kg / h of reture, pre-mixed with 4.63 kg / h of sodium humate (ratio of sodium humate: P ₂ O ₅ in the pulp 0.01: 1) with a particle size of 0.1 mm. BGS is blown with flue gases with an initial temperature of 280 ° C. Dried granules discharged from the DSS are dispersed. The result is 890 kg / h of a product containing: moisture 1%; N = 12%; P ₂ O ₅ = 52%; sodium humate 0.5% (the ratio in the product is sodium humate: P ₂ O ₅ = 0.01, i.e. there is no loss of sodium humate during the production of fertilizers), and 1000 kg / h of the retura of the same composition that is sent for mixing with sodium humate.

The increase in vegetable yield from the use of ammophos with humate was 20% compared with the same dosage of the mineral base, i.e. ammophos.

The results of other experiments are summarized in table 1.

Table 1 Mineral fertilizer base No. of experiments Humidity of the pulp,% The ratio of humate: P ₂ O ₅ in the product The increase in the crop of vegetables,% Ammophos one 8 0.01 twenty 2 fifteen 0.01 twenty 3 eighteen 0.01 5 Diammonium phosphate four 8 0.015 25 5 10 0.006 fifteen 6 fifteen 0.005 0 7 eighteen 0.018 10 Superphosphate 8 fifteen 0.006 fifteen 9 eighteen 0.005 0

As can be seen from table 1, the agrochemical effectiveness of the fertilizer decreases sharply when it goes beyond the proposed parameter values.

Using the proposed method can significantly reduce the loss of humate (due to the fact that it is inside the granule) and does not exfoliate when the product is mixed, which in turn naturally improves agrochemical properties (since there is no loss of humate). This reduces the caking of fertilizers.

Claims (4)

1. A method of producing granular phosphate fertilizer containing humate, including the manufacture of granules based on phosphorus-containing mineral fertilizer and alkali metal humate, characterized in that the process is carried out in a drum-type apparatus by spraying pulp of phosphorus-containing mineral fertilizer with a moisture content of 8-15% on retour, pre-mixed with bulk humate of an alkali metal with a particle size of not more than 0.15 mm. 2. The method according to claim 1, characterized in that the humate is pre-mixed with the reture either in a separate container or directly in a granulation apparatus. 3. The method according to any one of claims 1 and 2, characterized in that the alkali metal humate is introduced in an amount providing a ratio of humate to P ₂ O ₅ in the product of 0.006-0.015: 1. 4. The method according to any one of claims 1 to 3, characterized in that, for example, pulp of a phosphorus-containing fertilizer is taken, for example, pulp of ammophos, diammonium phosphate or superphosphate.