SU833503A1 - Method of ammonium nitrate production - Google Patents

Description

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The invention relates to the production of ammonium nitrate and the question of reducing the caking of the produced fertilizer granules.

A known method of producing non-caking fertilizers by coating the finished fertilizer granules with liquid ortho- and pyrophosphoric acids to form one or several coating layers l.

The disadvantage of this method of producing calcium nitrate nitrate is that surface additives contribute to achieving a short-term effect, since the effect of additives is limited by the adsorption capacity with respect to water.

At the same time, these additives do not perform structure-forming functions, which negatively affects the quality of the product. Moreover, the ballast material in large quantities significantly reduces the use value of the fertilizer.

The most desirable technical result and the achieved result is a method for producing ammonium nitrate, which includes introducing sulfuric acid into the initial nitric acid, neutralizing the resulting solution with ammonia, evaporating the resulting solution to a state of melting, melting granule, drying, cooling and processing - obtained granules dispersant NF 2,

The disadvantage of this method is that the degree of caking of the fertilizer is completely dependent on the integrity of the surface of the granules, which are dispersed by the dispersant NP. Mechanical damage to the surfaces of the granules, one way or another associated with the transportation of fertilizer,

5 cause a certain degree of caking of ammonium nitrate. Enter sulfuric acid leads to the formation of ammonium sulfate, which reduces the solubility

0 ammonium nitrate, increases the removal of crystals, but does not contribute to the reduction of caking and increase the strength of the granules.

The purpose of the invention is to increase

5 strength of the granules, reducing their caking and simplifying the process by eliminating the stage of processing the dispersant NF.

This goal is achieved by the fact that in ci; ioco6e the production of ammonium nitrate, including the introduction of a conditioning additive to the initial nitric acid, neutralization of the resulting solution with ammonia, evaporation of the resulting solution to a state of melting, granulation of the water, drying, cooling the granules, and packaging, as a conditioner -additives — use magnesium ammonium phosphate in an amount of 1.15 to 2.25% by weight of the total.

Also, the fact that magnesium ammonium phosphate is introduced into nitric acid, taken in an amount of 20-50% of its total amount.

In addition, magnesium ammonium phosphate is introduced as a paste with a moisture content of 40-50% or as an aqueous suspension with a solid: liquid ratio of 1: (2-3).

The amount of magnesium ammonium phosphate (1.15 - 2.25%) is due to the strength and caking of the obtained granules of ammonium nitrate. With a further increase in the amount of magnesium ammonium phosphate, strength increases and caking decreases, but the content of the basic substance decreases.

 If for dissolving Magnesium ammonium phosphate to take less than 20% of the acid from its total consumption, then it takes 4-5 minutes to dissolve, which affects the performance of the process as a whole. When the amount of acid is more than 50% of the total amount, no decrease in dissolution time (less than 1 minute) is observed.

Example 1. In a separate (1 m) reactor, the initial 45% nitric acid in an amount of 20 kg is fed, and a wet precipitate of magnesium ammonium phosphate is metered here with constant stirring for 1-2 minutes in an amount of 1.15 kg (in terms of dry matter). The prepared solution of magnesium ammonium phosphate in nitric acid is sent to the main reactor with 80 kg of 45% nitric acid, where the mixture is neutralized with ammonia gas after mixing. 57-59% solution of ammonium nitrate with magnesium-4-ammonium phosphate is evaporated to the state of melt (concentration of 5 salts is not less than 99%),

the melt is granulated in a granary, and the granules are dried, cooled and then packaged in bags. Ammonium nitrate granules are obtained in the amount of 58 kg, which contain about 2 wt.% Magnesium ammonium phosphate.

The mixing time of magnesium ammonium phosphate with nitric acid (1-2 minutes) is sufficient to completely dissolve the magnesium ammonium phosphate in nitric acid.

Similarly, experiments were carried out with different content of magnesium ammonium phosphate, the results are summarized in the table.

To compare the proposed method with a known background experiment, the results of which are also shown in the table.

Appearance Additives content of magnesium ammonium phosphate (MAF) to the total amount of the initial nitric acid (NNod),%

Mechanical strength of granules for grinding, kg / per granule (on average)

Granule structure

Caking, kg / cm

Amount of nitric acid required for mixing with MAF, in% to the total consumption of nitric acid

Gr an uly b ego go color

0.55 1.15 1.70 2.25 2.8

4.10 4.85. 5.73 6.47 7.60 Crystal

0.50

0.62

0.73

0/90

37,8

20

50

62.2

The table shows that the main indicators of the quality of ammonium nitrate vary depending on the amount of magnesium ammonium phosphate, previously added to nitric acid.

As the amount of magnesium monophosphate increases, the mechanical strength of the granules increases and the caking of the granules decreases. Already with an insignificant addition of magnesium ammonium phosphate (0.55%), the mechanical strength is increased 5 times, and caking decreases 2 times. A further increase in the amount of magnesium ammonium phosphate is impractical because it reduces the content of the basic substance. one

When using the proposed method, the expected economic effect only for Cherkassy software Lzot will be about 1 million rubles.

Claims (3)

1. A method of producing ammonium nitrate, including the introduction of a conditioning additive to the starting nitric acid, neutralization ammonia prepared solution, evaporation of the resulting solution to the state of melting, melting granulation, drying, cooling of the granules and packaging, characterized in that, in order to increase the strength of the granules, reduce their caking and simplify the process, magnesium ammonium phosphate is used as a conditioning additive in the amount of 1.15 - 2.25 wt.% Of the total. 2. The method according to A.1 / o tl and c o y and with the fact that magnesium ammonium phosphate is introduced into nitric acid. one taken in an amount of 20-50% of 5 of its total. 3. Method according to Claims 1 and 2, characterized in that the magnesium ammonium phosphate is administered in the form of a paste with a moisture content of 40 to 50% or in the form of Q aqueous suspension with the ratio of solid: liquid 1: (2-3). Sources of information taken in. attention during examination 1. US patent number 3392007, cl. From 01 to 1/18, published. 1968. 2. Pozin M.E. Mineral salts technolgy. L., Khimi, 1974, Part 11, p. 798, 1556 (prototype).