SU916508A1 - Method for preparing complex fertilizer - Google Patents

Description

The invention relates to the production of mineral fertilizers and can be used to obtain complex fertilizers nitric acid-acid processing of natural phosphates

high in magnesium.

A method is known for producing complex rhenium with ^{5 * * * *} decomposition of phosphates by nitric acid and a circulating mixture of nitric and phosphoric acids, followed by treatment with sulfuric acid extract, separation of calcium sulphate, ammonia- ^{10 * * *} solution, evaporation, mixing with potassium salt and drying the product (1].

The processing of phosphates with a high magnesium content by this complex method is difficult due to poor filtering ^.

properties of the resulting precipitate of calcium sulfate.

The closest to the proposed

technical essence is a way to get _χ

complex fertilizer by decomposition

high-magnesium phosphate raw material with nitric acid and a circulating mixture of nitric and phosphoric acid, followed by

2

treating the nitrophosphonan extract with sulfuric acid, separating the calcium sulfate precipitate by filtration, returning one part of the filtrate to the decomposition stage of the phosphate raw material, ammonifying the other part, evaporating the resulting pulp, mixing it with potassium salt and drying the product [2].

The disadvantage of this method is low productivity and filtration of calcium sulphate precipitate (400-600 kg / m ² · h), as well as the difficulty of evaporating ammoniated pulp due to the presence of a significant amount of solid phase in it, which leads to a low use of evaporation equipment, not exceeding 70%.

The purpose of the invention is the intensification of the process of obtaining complex fertilizers.

This goal is achieved by the fact that in the method of obtaining complex fertilizers by the decomposition of high-magnesium phosphate raw materials with nitric acid in the presence of a circulating mother liquor followed by treatment of sulfuric acid with nitrophosphoric acid extract, separation of sulphate precipitate,

3 916508 4

returning the mother liquor 45-47% per cycle, ammoniation other part, its evaporation, formed by mixing pulp with the potassium salt and drying the product, the mother liquor ammoniation is continued until the residual content of 5 Nogo 0.1-0.5% MgO and the ratio ^Ν 0ΜΠ ^{: Ρίθί =} 7-0.25, then from 50-72%

the ammoniated mother liquor separates the magnes-containing precipitate and supplies it to the pulp-potassium salt mixing stage, while the remaining solution is fed to the nitrogen-phosphoric acid extract stage with sulfuric acid.

Example 1. The raw material used phosphorite Karatau field 15 composition, wt.%: P ₂ O ₅ 22,6; CaO 41.0; MDO 4.6; CO ₂ 0.8.

100 kg of phosphorite are treated with 78.4 kg of 50% nitric acid and 200 kg of working solution (at the same time 20 8 kg of CO _{2 are} incorporated into the gas phase) to obtain 370.4 kg of exhaust. The latter is treated with 76.5 kg of 93% H _{2 2 4} in the presence of 80 kg of wash water and 100 kg of anesthetic solution with a residual content of 0.1% MgO and a ratio of 25 M _amp : P _g O ₅ ^{= this is the} liquid phase

the ratio MDO: P ₂ O ₅ = 0.08 and N: P ₂ O ₅ = 0.135).

626.9 kg of pulp is filtered and the precipitate is washed with 80 kg of water. 186.9 kg of calcium sulphate is dumped into the dump, and 440 kg of the filtrate is divided into two streams: 200 kg is sent to the stage of decomposition of phosphate (working solution), and 240 kg of the filtrate is ammoniated

16.8 kg ΝΗ ₃ to a residual content in the solution of 0.1% MgO and ratios = 0.25.

130 kg (50%) of the mass of ammoniated non-evaporated pulp are filtered; 100 kg of anmagnetised solution are introduced into the process before the separation of calcium sulfate, and 30 kg of magnesium- ⁴⁰ sludge is fed to the stage of mixing with potassium salt. 126.8 kg of ammoniated pulp served on uparka. After evaporation

35.2 kg Water 91.6 kg of the evaporated slurry was mixed with 33.4 kg of KC1, 30 ⁴⁵ kg of magnesium containing precipitate present and the resulting mixture is dried with removal of 30 kg H ₂ O. _The 125 kg of finished product are fertilizer grade M: P ₂ O ₅ :: K ₂ O = 16: 16: 16.

The removal of dry washed calcium sulphate precipitate ⁵⁰ is 2200 kg / m ² h, and the degree of use of evaporated equipment is 80%.

Example 2. 370,4 kg hood, obtained analogously to example 1, is treated

76.5 kg of 93% H ₂ 5O ₄ in the presence of 80 kg of ⁵⁵ wash water and 300 kg of anmagnetised solution with a residual content of 0.5% MgO and the ratio ⁼ θ "17 (

in the liquid phase, the ratio MDO: P ₂ O ₅ "=

0.15 and Ν0 ^ _μ ; Ρ ₂ Ο ₅ = 0.09). 826.9 kg of pulp is filtered and the precipitate is washed with 80 kg of water.

186.9 kg of calcium sulphate is dumped into the dump, and 640 kg of the filtrate is divided into two streams: 200 kg is sent to the stage of decomposition of phosphate (working solution), and 240 kg of the filter are ammoniated 14.8 kg ₃ to a residual content in the solution 0.5 % MDO I relationship ^ «ΜΜ · ² θ ^{5 =} θ '!? ·

328 kg (72%) of the mass of ammoniated non-evaporated pulp is filtered. 300 kg of the anmagnetised solution are introduced into the process before the separation of calcium, and 28 kg of the magnesium-containing sediment are fed to the stage of mixing with the potassium salt. 126.8 kg of ammoniated pulp is processed into the finished product as in Example 1.

Removal of dry washed calcium sulphate precipitate is 1600 kg / m ² 'h, and the degree of use of equipment is 85%.

Example 3. 370 kg hood, obtained analogously to example 1, is treated

76.5 kg of 93% Η ₂ δΟ ₄ in the presence of 80 kg of wash water and 200 kg of anesthetic solution with a residual content of 0.2% MgO and the ratio Ν _αΜΜ .Ρ ₁ Ο $ = 0.2 (in the liquid phase the ratio of MDO: P ₂ O, = 0.12 and ^ _vmYa- p2O $ = 0.11). 726.9 kg of pulp is filtered and the precipitate is washed with 80 kg of water.

186.9 kg of dry calcium is dumped into the dump, and 540 kg of the filtrate is divided into a flow: 200 kg is sent to the phosphate decomposition stage (working solution), and 340 kg are ammoniated 15.3 kg ₃ and the residual content in the solution is 0.2% and relationships

= θ> 2.

228.5 kg (65%) of the mass of ammoniated undone pulp is filtered. 200 kg obezmagnennogo solution is introduced into the process before otdele- ^- 'Nia calcium sulfate, and 28.5 kg of magnesium sludge is fed to the mixing step with the potassium salt, 126.8 kg of ammoniated slurry is processed into finished product as in Example 1.

Removal of dry washed calcium sulphate sediment is 1800 kg / m ² · h, and the degree of use of evaporation equipment is 82%.

Thus, the implementation of the proposed method allows to intensify by increasing the filtration performance of the precipitate calcium sulphate from 400-600 to 16002200 kg / m ² · h and increasing the performance of the evaporation stage of ammoniated pulp and 14.3-21.4%. .

Claims (1)

Claim A method of obtaining a complex fertilizer by decomposition of high-magnesium phosphate raw material with nitric acid in the presence of turnover5 916508 6 the mother liquor with the subsequent mother liquor is separated treatment with aero phosphoric acid stretching. sulfuric acid, “precipitation of sulphate calcium”, returning 45–47% of the mother liquor to the cycle, ammonizing another part of it, evaporating it, mixing the resulting pulp with potassium salt and drying the product, in order to intensify the process , ammonization of the mat solution is carried out to a residual content of 0.1-0.5% MdO and the ratio Ν _ΟΙΜ <ΡιΟί · 0.17-0.25, then from 50-72% ammo, the magnesium-containing precipitate is fed to the pulp mixing stage potassium salt, and the remaining solution is fed to the stage of processing aeotrophosphoric acid sulfuric acid extracts.