SU865861A1 - Method of producing complex fertilizer - Google Patents

Description

(54) METHOD OF OBTAINING COMPLEX FERTILIZER

one

The invention relates to methods for the preparation of complex fertilizers by the nitric acid processing of natural phosphates.

A known method of producing a complex fertilizer is by nitric acid decomposition of phosphate raw materials, followed by freezing of tetrabasic nitrate calcium, ammonization of the resulting acidic solution, pulping, mixing with potassium salt, drying and granulation 1.

The closest one to the technical essence and the achieved result is the method of obtaining complex fertilizer by decomposing the phosphate raw material with nitric acid followed by release of calcium nitrate by freezing, hyimonizing the resulting acidic mother liquor with gaseous ammonia to pH 4.5-5, Oj, pulping, mixing with potassium salt and granulation 2.

A disadvantage of the known methods is the low content of the water-soluble form of phosphoric anhydride in the final product due to the formation of water-insoluble iron salts, in which about 2 mol are per mole.

The purpose of the invention is to improve the quality of the product by increasing the content of water-soluble phosphates in it.

The goal is achieved by the fact that in the known method of producing complex fertilizer by decomposing phosphate raw materials with nitric acid, followed by separation of calcium nitrate, ammoniation of the resulting acidic mother liquor, evaporation of the pulp, mixing with potassium salt, drying and granulation, the acidic precursor is served

15 to the ammoniation zone with a pH of 6-8 and after 30-60 minutes of stirring, acidify with nitric acid or a starting nitrogen-phosphate mother liquor to pH 3-5.

20

Using this technique allows iron phosphates to be precipitated with the ratio Fe jO: P. OOS to bind the remaining amount of phosphate in the form of water-soluble ammonium phosphate

25 by precipitation of iron phosphates, with a lower phosphorus content, for example (PO4) r OH-2HaO. The amount of water-insoluble phosphate in the fertilizer is reduced by 2 times and is only 10-15% of the total.

30 Example 1, The raw material used is calcined with phosphorus of the Tsko-Kamsky deposit, wt.%: 24.5; Sio 40.2; Fe / jOj 7.0; AEjO 1.4; F 1,8; and about. 16.0; FeQO, j: 28.6%. The mother liquor obtained by decomposing phosphate with 54% nitric acid (normal 120% of stoichiometry), freezing calcium nitrate at 15 ° 6, followed by separation by filtration and precipitating residual calcium with sulfuric acid, has the following composition;%: P, 05- 24, HNOe 36.5, 3.5 ,, AVdOz, KjO 34.5 and CaO 0.5, 100 kg of the solution of the said composition are fed to the ammonization zone with a pH of 8 simultaneously with 12 kg of gaseous ammonia and incubated for 30 minutes. At the same time, iron phosphates are precipitated into the solid phase, in which 3.5 kg of the initial solution binds 3.5 kg instead of 7 kg according to a known method (in the case of a gradual increase in the pH of the pulp). The resulting 112 kg of pulp is acidified with 2 kg of starting stock solution to lower the pulp pH to 4.5. Then, 17 kg of a 50% NH4NO solution at the N-P equilibration conversion step is added to the pulp and evaporated. After removal of 31 kg of HPO, 28 kg of potassium chloride (60% of KO) is added to the pulp (100 kg). The obtained 128 k of pulp is dried to obtain 100 kg of a gothic product (N: PaO5: Kg (O 16:16:16))

The length and consistency of the mixture to be intermixed in cooking, fresh food,%

It is not feasible due to the increased consumption of ammonia and the release of iron hydroxide. It is not feasible due to the increase in equipment

The product is obtained with a lower content due to the release of a mixture of iron phosphates with the ratio: P2.0jr 1: 1 and 1: 2.

Note

Claims (2)

In the known method, the content of water-soluble in the finished product 64% nitroammofoski. The fertilizer contains 85% in water-soluble form instead of 64 by a known method due to the lesser amount associated with iron salts. PRI mme R 2. 100 kg of the solution, as in Example 1, is fed to the ammonization zone with a pH of 6 at the same time as 6 kg of gaseous ammonia and held for 60 minutes. In this case, iron phosphates FeaOj: PjQj .: fall out into the solid phase (with the same ratio as in example 1). To 106 kg of pulp, add 1.5 kg of nitric acid with a concentration of 54% HNOj to lower the pH to 4.5. Then, to 107.5 kg of the obtained pulp is added 17 kg of a 50% aqueous solution of NNDO with the conversion of calcium nitrate to balance the ratio NsP / j Oj. After evaporation of 24.5 kg of water, 28 kg of potassium chloride 60% (Cor) is added to the pulp (100 kg). 128 kg of pulp is dried to obtain 100 kg of the finished product (N: Kg O 16:16:16) nitroammofoski containing 82% in water-soluble form instead of 64% by a known method. The table provides examples of how the process is conducted within the proposed limits of the characteristic values, while values beyond these limits. From the table it can be seen that with the values of the parameters going beyond the proposed limits, it is economically or technologically inexpedient to conduct the process. 586586 Claim of the invention. A method of obtaining a complex fertilizer by decomposing a phosphate raw material with nitric acid followed by separation of calcium nitrate, ammonium. the solution of the resulting acidic liquor, solution of pulp, mixing with potassium salt, drying and granule, characterized in that, in order to improve the quality. due to the increase in the content of water-soluble phosphates in it, the 16 acidic mother liquor is preliminarily fed to the ammonization zone with a pH of 68 and, after 30-60 minutes of stirring, acidified with nitric acid or the starting nitrogen-phosphate mother liquor to pH 3-5. Sources of information taken into account in the examination i. patent Czechoslovakia 142469, cl. I2i 25/28, 01/26/68. 2. Largolis F.G., Karmyshov V.F., Glazova T.V. Works NIUIF. Issue 221, p. 46-55 (prototype).