SU1117290A1 - Method of obtaining complex mineral fertilizer - Google Patents

Abstract

1. METHOD OF OBTAINING A COMPLEX MINERAL FERTILIZER by decomposing a popigalite with a mineral acid followed by non-neutralization of the reaction mass, characterized in that nitrogen is used as a mineral acid to increase the content of elements available to plants acid, and neutralization lead calcium product, followed by the separation of the resulting gypsum from the mother liquor and evaporation of the latter. 2. The method according to p. 1, characterized in that the separated gypsum S is washed with water and the washings are returned to the decomposition of polyhalite ate with nitric acid.

Description

The invention relates to the production of complex mineral fertilizers, in particular ballastless, and can be used in the processing of, for example, polygalite.

A known method of producing complex mineral fertilizers by decomposition of polygalite with mineral acid [1 J.

However, this method does not allow 1® to eliminate the content of ballast ions, is characterized by multi-stage and high complexity due to the inclusion of expensive Qij processes in it.

Also known is a simpler method for producing complex mineral fertilizers [2].

However, the known method also does not allow to eliminate the content of ballast ions Ca ²⁺ and S0 ^ ^_ in the fertilizer and to increase the content of elements available for plants. According to the method, polygalite is decomposed with phosphoric acid at 25 ° C, followed by neutralization of the reaction mass with 25% ammonia water and drying of the product at 70 ° C to obtain NPK fertilizer. The decomposition of polygalite with phosphoric acid, followed by neutralization of the reaction mixture with .30 ammonia water, leads to the formation of fertilizers containing calcium and magnesium phosphates in the form of water-insoluble salts and potassium and ammonium sulfates as soluble salts. 35

The content of such salts in the fertilizer does not provide a high content of elements available for plants, and to eliminate the content of ballast impurities of Ca ²⁺ and 5O ² ~ ions. 40

The aim of the invention is to increase the content of elements available for plants, and the elimination of the content of ballast ions Ca ²⁺ and 50 ² '.

This goal is achieved by the fact that, according to the method for producing complex mineral fertilizers, including the decomposition of polygalite with mineral acid and subsequent neutralization of the reaction mixture, nitric acid is used as mineral acid in 5θ, and neutralization is prevented by a calcium-containing product, followed by separation of the resulting gypsum from the mother liquor and by tapping the last one.

In addition, the separated gypsum is washed with water and the washings are returned to the decomposition of polygalite with nitric acid.

The use of nitric acid as a mineral acid makes it possible to obtain complex fertilizer in a water-soluble form (potassium and magnesium nitrates), which increases the content of elements available for plants, and the neutralization of the reaction mass with a calcium-containing product ensures the release of ballast impurities of Ca ²⁺ and SO ² ions in the form gypsum. Return wash 15 _; water at the stage of decomposition of polygalite allows the method in a closed cycle.

Example. The proposed method is carried out on a model plant, 100 kg of polygalite (in terms of dry product) are mixed in the reactor with 76.93 kg of 54.4% nitric acid and with 235.59 kg of wash water. The resulting 25 mixture was stirred for 2.5 hours at 90 ° C, after which 33.24 kg: chalk were neutralized. The precipitated gypsum is separated and washed with 250.46 kg of water, resulting in 212.88 kg of washed gypsum, 243.18 kg of mother liquor and 235.59 kg of wash water. The washed gypsum is discarded, the wash water is returned to the decomposition stage, and the mother liquor is fed to the residue. At the evaporation stage, 186.09 kg of water is removed and 57.04 kg of product is obtained. The chemical compositions of the starting materials, intermediate and finished products are presented in the table. The degree of extraction of potassium and magnesium in the product is 95%, the degree of decomposition of polygalite is 100%.

Using the proposed method for producing complex mineral fertilizers by decomposing polygalite with mineral acid followed by neutralization of the reaction mass in comparison with the known ones allows to increase the content of elements available for plants, eliminates the content of ballast impurities of ioi Ca ²⁺ and SO ^2. · Differs in the simplicity of the technological scheme and not requires large capital costs for the organization of production.

VNIIIPI Order 7143/16 ___ Circulation 425 ___ Subscription

Branch of the PPP Patent, Uzhgorod, Project 4,

Claims (2)

1. METHOD FOR PRODUCING INTEGRATED MINERAL FERTILIZER by decomposition of polygalite with mineral acid followed by neutralization of the reaction mass, characterized in that, in order to increase the content of elements available to plants, and to eliminate the content of ballast impurities of Ca ²⁺ and 5O ² ions as a mineral acid nitric acid is used, and neutralization is carried out with a calcium-containing product, followed by separation of the formed gypsum from the mother liquor and evaporation of the latter. 2. The method of pop. 1, characterized in that the separated gypsum is washed with water and the washings are returned to the decomposition of polygalite with nitric acid.