RU2182144C1 - Method to obtain complex n:k fertilizer - Google Patents

Abstract

FIELD: agriculture. SUBSTANCE: during the process to obtain ammonium nitrate out of ammonia and nitric acid at the stage of neutralization it is necessary to add potassium nitrate as 30- 70% solution at 2-20% weight against ammonium nitrate content. Then mixed solution is processed to obtain a ready-touse product by concentration and granulation due to the well-known technique. Complex fertilizer mentioned contains, weight%: N 34.2-30.4, K₂O 0.9- 9.3. The fertilizer obtained contains no chlorine. EFFECT: improved quality and agrochemical value, increased parameters of technological process due to introduction of potassium nitrate. 3 cl, 1 dwg

Description

 The invention relates to the chemical industry and can be used at enterprises producing mineral fertilizers.

 Known methods for producing complex N: K fertilizers by mechanical mixing of powdered or granular nitrogen-potassium-containing products or by mixing them with the introduction of liquid reagents (melt ammonium nitrate, nitric acid, ammonia) followed by granulation of the mixture (M.E. Pozin, "Technology of mineral salts ", vol. II, p. 1364," Chemistry ", 1974).

 The disadvantage of these methods is the segregation of fertilized mechanical mixtures, and in the case of granulation of the mixtures after or in the mixing process, the technical and apparatus complexity of such a process.

 The closest in technical essence is the method of producing nitrogen-potassium fertilizer (Dukhanin B.F., Serebryakov A.I., RF patent 2154620 dated 01/14/2000).

 The disadvantage of this method, in addition to the above, is the use of potassium chloride as a potassium-containing component, which leads to corrosion of the equipment and reduces the agrochemical value of the fertilizer due to the introduction of a chlorine ion.

 The aim of the invention is to improve the quality and agrochemical value of fertilizers by improving process parameters and the inclusion of a second nutrient in the product.

This goal is achieved by introducing into the composition of ammonium nitrate an addition of potassium nitrate in an amount of 2-20 wt.% Of the amount of ammonium nitrate, and to simplify the process, potassium nitrate is introduced at the stage of neutralization of nitric acid with ammonia gas in the form of a 30-70% solution. The improvement of the process parameters is manifested at the stage of evaporation of the mixed solution of ammonia and potassium nitrate. It was found that the introduction of potassium nitrate greatly facilitates the removal of residual moisture from the melt. So, when evaporating a solution of ammonium nitrate with a concentration of 90% without additives, the moisture content in the product is 0.4-0.6%, and when introduced, for example, 2-10 wt. % KNO ₃ humidity does not exceed 0.2-0.3%, despite the dilution of the initial mixed solution by the addition of potassium nitrate to a concentration of 82%. The upper limit of the content of potassium nitrate additive (20%) is determined by the fusibility diagram of the NH ₄ NO ₃ -KNO _{3 system} (Handbook "Salt fusion diagrams of salt systems", part II, M. 1977, p. 87). Mixtures containing KNO ₃ more than 20% have a crystallization temperature above 170 ^o C, which can lead to decomposition of ammonium nitrate.

 The drawing shows a diagram of an implementation of the method of producing nitrogen-potassium fertilizer.

Non-concentrated nitric acid with a content of 56-58 wt.% HNO ₃ and gaseous ammonia are fed to neutralization, which results in the formation of an 85-90% solution of ammonium nitrate. At the same time, a 30-70% potassium nitrate solution is continuously fed into the same apparatus. A mixed product containing 2-20 wt. % KNO ₃ , after neutralization is sent to the evaporator and then in the form of melt to granulation. After air cooling in fluidized bed apparatuses, the granular product enters the packaging.

 Example 1

 0.3 kg of a 65% potassium nitrate solution is added to 1 kg of an 85% ammonium nitrate solution. The mixture of solutions is stirred and evaporated to a residual moisture content of 0.3%. A highly concentrated molten salt is crystallized by the method of "granulation in liquid" to obtain granules of the finished product.

The resulting complex fertilizer contains,%:
N - 31
K ₂ O - 8.7
Example 2

0.25 kg of a 50% KNO ₃ solution are added to 1 kg of an 87% NH ₄ NO ₃ solution. Next, the process is conducted as in example 1.

The resulting complex N: K fertilizer contains,%:
N - 32.2
K ₂ O - 5.8
Example 3

To 1 kg of a 90% solution of NH ₄ NO ₃ add 0.1 kg of a 30% solution of KNO ₃ . Next, the process is conducted as in example 1.

The resulting complex fertilizer contains,%:
N - 34.2
K ₂ O - 1.5-

Claims (3)

 1. The method of obtaining complex N: K fertilizer, including neutralizing ammonia with nitric acid, mixing with a potassium-containing additive, evaporating the mixed solution and granulating the melt, characterized in that the potassium is introduced at the stage of neutralization in the form of a 30-70% potassium nitrate solution based 2-20 wt. % of the amount of ammonium nitrate.  2. Complex N: K fertilizer prepared according to the method according to p. 1. 3. Integrated N: K fertilizer according to claim 2, characterized in that it contains, by weight. %: N 34.2-30.4; K ₂ O 0.9-9.3.