RU2230028C1 - Method for preparing porous granulated ammonium nitrate - Google Patents

Abstract

FIELD: inorganic chemistry, chemical technology. SUBSTANCE: invention relates to technology for preparing inorganic salts used for preparing the simplest explosive substances. Method for preparing porous granulated ammonium nitrate involves neutralization of ammonia with nitric acid, evaporation of solution to obtain the concentrated melt consisting of hydrolysable trivalent metal salts and mixing with an aqueous suspension containing the combination of water-soluble sodium or potassium carbonate and calcium carbonate suspended in this solution as a pore-forming agent. The concentration of sodium or potassium carbonate is 5-15% and the content of calcium carbonate is 30-50% of the total mass of suspension feeding to mixing. An aqueous suspension containing a pore-forming agent is added in the amount 0.1-0.4% of ammonium nitrate amount. Method provides preparing porous ammonium nitrate with improved physical-chemical properties. EFFECT: improved preparing method. 2 cl, 1 tbl, 2 ex

Description

The invention relates to the technology of inorganic salts used to produce simple explosives.

Numerous methods are known for producing porous granules of ammonium nitrate, both by using various pore-forming additives in the crystallization process and by heat treatment of its granules (Ammonium nitrate technology, ed. V.M. Olevsky. - M .: Chemistry, 1978, p. 233-239). Two of the first group of methods in our country have found practical application (Pat. RF No. 2078065 of 02/01/1994 and Pat. RF No. 2010023 of 04/29/1992). The general idea of these methods is the use of carbon dioxide metal salts for the formation of pores: according to the patent of the Russian Federation No. 2078065 of February 1, 1994 calcium carbonate (aqueous suspension of chalk), according to the patent of the Russian Federation No. 2010023 of April 29, 1992 a solution of soda ash. Both of these methods can be taken as a prototype of the invention, but the closest in technical essence is the method according to the patent of the Russian Federation No. 2078065 of 02/01/1994.

According to the invention-prototype, a method is used to produce porous granular ammonium nitrate by neutralizing ammonia with nitric acid, evaporation, sequentially introducing ferric sulfate and pore-forming additives into a concentrated melt, the main agent of which is an aqueous suspension of calcium carbonate, granulation and processing of granules with a surface-active additive.

The disadvantage of this method is that calcium carbonate practically does not interact with the melt of ammonium nitrate, more precisely, the reaction of gas formation

proceeds under conditions preceding granulation (t = 170 ° C) very slowly. This requires introducing hydrolyzable salts (for example, Fe ₂ (SO ₄ ) ₃ ) into the melt to increase its acidity and the gas formation reaction proceeds mainly with acid

The objective of the proposed invention is to improve the physico-chemical properties of porous ammonium nitrate (humidity, pellet strength, absorbent ability to diesel fuel).

This goal is achieved in that, as a pore-forming agent, a combination of water-soluble sodium or potassium carbonate and calcium carbonate suspended in its solution is used, the concentration of sodium or potassium carbonate being 5-15% and the content of calcium carbonate 30-50% of the total weight of the suspension fed to the mix.

The use of the proposed combination significantly increases the effectiveness of the pore-forming agent due to the direct interaction of dissolved carbonate with ammonium nitrate. At the same time, the volume of ballast moisture is reduced and the other physicochemical properties of the porous granules are improved.

Example 1. In a concentrated melt of ammonium nitrate containing oxide iron in an amount of 0.05 wt.%. (in terms of Fe), a pore-forming agent is introduced, which is an aqueous solution of sodium carbonate, a concentration of 10 wt.%. and suspended in it calcium carbonate in an amount of 36.8 wt.%. In addition, the suspension contains an NF dispersant (7.2%) and 0.2% sodium stearate. The pore-forming agent consumption is 45 l / h, which corresponds to 2.4 kg per 1 ton of product (0.24%).

Mixed melt enters the granulator. After cooling, the granules are treated in a drum with a surfactant.

The resulting product has the main indicators shown in the table (the data are given in comparison with the requirements of technical specifications, which correspond to the porous granular nitrate produced at OJSC "Nitrogen" by the prototype method).

Example 2. In a concentrated melt of ammonium nitrate containing oxide iron in an amount of 0.05 wt.%. (in terms of Fe), a pore-forming agent is introduced - an aqueous solution of potassium carbonate with a concentration of 5 wt.%. To ₂ CO ₃ and calcium carbonate suspended in it in an amount of 45 wt.%. The remaining components are the same as in example 1.

The mixed solution enters the granulator. After cooling, the granules are treated in a drum with a surfactant.

The resulting product has the following main indicators (the data are shown in table 1 in comparison with the requirements of technical specifications, which corresponds to the porous granular nitrate produced at OJSC "Nitrogen" by the prototype method).

Claims (2)

1. A method of obtaining a porous granular ammonium nitrate, including neutralizing nitric acid with ammonia, evaporating the solution to obtain a concentrated melt, introducing hydrolyzed salts of trivalent metals into the melt, mixing with an aqueous suspension containing a pore-forming agent in the form of a carbon dioxide metal salt, sodium or ammonium salt of methyl disulfonic acid (NF dispersant) and sodium or potassium stearate, granulation of the resulting mixture with subsequent processing of granules with surface-active additives, excellent characterized in that as a pore-forming agent, a combination of water-soluble sodium or potassium carbonate and calcium carbonate suspended in its solution is used, the concentration of sodium or potassium carbonate being 5-15% and the content of calcium carbonate 30-50% of the total weight of the suspension supplied to the mix. 2. The method according to claim 1, characterized in that the aqueous suspension containing a pore-forming agent is administered in an amount of 0.1-0.4% of the amount of ammonium nitrate.

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