SU618362A1 - Method of obtaining complex fertilizer - Google Patents

Description

(54) METHOD OF OBTAINING COMPLEX FERTILIZER

one

The invention relates to a method for producing a complex fertilizer by the nitric acid processing of phosphates.

A method is known for producing a complex fertilizer by decomposing a phosphate raw material with nitric acid, followed by separating calcium ions by freezing and processing the acid extract into a complex fertilizer l,

The technical essence and the achieved result most closely resembles the method of obtaining complex fertilizer by decomposing phosphate raw materials with nitric acid, followed by separating calcium ions with sulfate ions, neutralizing the acid extract with gaseous ammonia, mixing with potassium salt and drying the finished product 2.

A disadvantage of the known methods is the bonding of a part of phosphoric anhydride (" 50%) with compounds of sesquioxides and magnesium, which passed to the acid decomposition stage in a water-insoluble or citrate-soluble form in the process of isolating, which greatly impairs the properties of the finished product.

The aim of the invention is to increase the proportion of the water soluble form of phosphoric anhydride in the final product.

The goal is achieved by the fact that according to the proposed method, before neutralization, potassium sulfate is introduced into the acid extract to a ratio: equal to 0.1: 1 -O, 25: 1.

Claims (2)

The introduction of potassium sulphate is explained by the fact that in an acidic medium, the sulphate interacts with magnesium salts and compounds of sesquioxides in the acidic medium to form highly soluble magnesium and ferrous sulphates, as well as potassium nitrates and phosphates, which prevents np-. - i ammonization of the binding of phosphoric anhydride to ammonium phosphates of magnesium and iron. Potassium sulfate is injected to a ratio of: 0.1: 1: 0.25: 1, since with the introduction of large quantities thick viscous pulps are obtained and, as a result, the exchange of potassium sulfate with compounds is slowed down. To obtain a fertilizer with a K, O: PgOs ratio greater than 0.25: 1, an additional amount of potassium salt can be introduced into the already neutralized pulp just before drying. Thus, with such an introduction of the process, substandard phosphates can be processed, as well as mineral fertilizers with a reduced chlorine content. Example. During decomposition, the ore of the Karatau Basin of composition is used, wt.%: Pj, O525.2j CaO 30.4; MgO 3.85, 6; P 2,4. At SO weight.h. phosphorus that take 92 weight.h. 47% nitric acid, 300 parts by weight of a circulating mixture of acids and 7.4 parts by weight. 93% sulfuric acid. After the decomposition of phosphate, part of the solution (300 parts by weight) is sent to the decomposition stage to maintain the desired ratio W: T, and the other part (240 parts by weight) is recycled to the desired product. This solution has the following composition,%: P O 13.2; NHS 23.6; P 0.27; 0.24; AEjOj 0.23; 1.4. 16.8 parts by weight are added to the mixture of nitric acid and phosphoric acid of the above composition. potassium sulfate to a ratio of: equal to 0.25: 1, neutralize it to pH 5 and mix the pulp with 23.1 parts by weight. potassium chloride. After drying, 144 parts by weight are obtained. product of the following composition,%: TjOy, uj.l5 PlOgycB. 14.9; . 14,. 15, 15.2. The retrogradation of the water-borne form of phosphoric anhydride is 64, i.e. 20% lower than in the known process without potassium sulfate, where the retrogradation of the water-soluble form of phosphoric anhydride is 26%. The invention method for producing complex fertilizer by decomposing phosphate raw materials with nitric acid followed by separation of calcium ions, neutralizing the acid extract with gaseous ammonia, mixing with potassium salt and drying the finished product, characterized in that in order to increase the proportion of the water-soluble phosphoric anhydride in the finished before neutralizing the product, potassium sulfate is introduced into the acid extract to a ratio of K, A: Equal to 0.1: 1 - 0.25: 1. Sources of information taken into account in the examination: 1. German patent 1467394, cl. C 05 V 11/06, 16.12.71. 2. Pozin ME, Kopylev BA, Sat. New research on mineral fertilizer technology. L., Himi, 1970, p. ten.