SU1500640A1 - Method of producing complex fertilizer - Google Patents

Description

The invention relates to methods for producing complex fertilizers from phosphate raw materials by its decomposition with mineral acids and allows2

It reduces the consumption of sulfuric acid and improves the filtration performance of the pulp while maintaining the quality of the finished product. The method is carried out by decomposition of the part (10—

40% of the total) phosphate feedstock with a mixture of phosphoric acid and ammonium sulfate, followed by filtering the resulting pulp, processing the liquid phase for mineral fertilizer such as ammonia, processing the solid phase with sulfuric acid and returning the resulting phosphoric acid to decompose the remaining part of the phosphate feedstock. 1 tab.

The invention relates to methods for producing complex fertilizers from phosphate raw materials by its decomposition with mineral acids.

The purpose of the invention is to reduce the consumption of sulfuric acid and improve the filtration performance of the pulp while maintaining the quality of the finished product.

The method is carried out by decomposing part (10-40%) of phosphate raw material with a mixture of phosphoric acid and ammonium sulfate, followed by filtering the resulting pulp, processing the liquid phase into mineral fertilizers such as ammophos, processing the solid phase with sulfuric acid and returning the resulting phosphoric acid to decompose the remaining part of the phosphate raw material .

When implementing the method of fundamental importance is the supply of phosphate raw materials in the above quantities for the processing of phosphoric acid in two stages.

When applying to the first stage, in which decomposition is carried out with phosphoric acid and ammonium sulfate, less than 10% or more than 40% of phosphate raw materials from the total amount decreases the filtration performance of the pulp and increases the consumption of sulfuric acid

at the stage of sulfuric acid decomposition, 1 “because the rate of interaction between phosphoric acid and phosphate raw materials decreases as the product of the calcium salt of phosphoric acid in the liquid phase accumulates, and the phosphate raw material has a heterogeneous particle size distribution and the reaction ends first

5 and „„ 1500640

1500640

between phosphoric acid and the fine fraction,

When 1040% of phosphate raw materials are introduced into the first stage, the phosphoric acid ^{- the} lot completely or almost completely uncovers this amount, which reduces the consumption of sulfuric acid and produces a crystalline precipitate that is well filtered. ”When introduced into the first stage, more than 40% of the raw materials remain in small fractions raw material and the result is a heterogeneous composition of the sediment, which affects the filtration performance. 15

The preliminary mixing of ammonium sulphate with phosphoric acid for the treatment of phosphate raw materials is also of significant importance. ^ 5 du phosphoric acid and raw materials for the sulfuric acid stage. The implementation of preliminary mixing of ammonium sulfate with phosphoric acid enhances the effect obtained from the fractional, 30 supply of phosphate raw materials.

Example. As the phosphate raw materials, the Kola apatite is taken (since it is harder to break with phosphoric acid compared to phosphates of sedimentary origin) in an amount of 125 g at a moisture content of 20%, which corresponds to 100 g of raw materials calculated on the dry product.

The sample is treated with 1.85 g of extraction phosphoric acid (EPA) containing 28% Ρ ^ Ος- and 42 g of 40% ammonium sulfate solution, agitated • 1 · 4 'at 70 ° C. The resulting pulp is filtered out under vacuum on a Büchner funnel through a filter cloth. This gives 169 g of unwashed sediment and 178 g of filtrate containing%: P ₂ 0 ₅ 25.6; CaO 2.1; 50 ₄ 1.28. From ^{50 of} this solution receive ammophos, containing,%: P _g 0 _5usb 53.4; P _a 0 _{e6 / p} 50.4; 11.4, The solid phase (sediment) decompose 79 g of 92% sulfuric acid. (727 kg / t. Apatite). This gives 185 g of EPC (P _{r 0?} 28% H ₂ 5O _4izm, 1.5%), which was sent to the remainder of the processing -apatita ,, and

150 g of calcium sulfate dihydrate containing 1.07% P ₂ 0 $.

The results obtained are presented. us in the table "

It follows from the table that, according to the prototype method, the consumption of sulfuric acid for the decomposition of apatite is 727 kg / t, while the filtration performance of the pulp obtained after apatite "is 46 t / m ²

day (experiment 7), according to the proposed method, experiments 1-6 consumption of sulfuric acid is 660-674 kg / t of apatite, and filtration performance is 94-, 121 t / m ² days.

one, ·

Thus, (10-40% at stage I and 60-90% at IX). Significantly reduces the consumption of sulfuric acid and improves filtration performance.

Preliminary mixing of ammonium sulfate with phosphoric acid enhances the effect obtained from feeding apatite in two stages. Processing the mixture of (ΝΗ ₄ ) ₂ 80 ₄ and H ^ PO ^ of the total amount of phosphate raw materials (test 8) results in the consumption of sulfuric acid and impairs filtration performance "

Thus, the implementation of the process in this mode allows to reduce the consumption of sulfuric acid in the production of ammophosphate from apatite concentrate to 660-670 kg / t and at the same time to increase 2.3-2.6 times the filtration performance of the pulp after treatment of phosphate raw materials with phosphoric acid and ammonium .

Claims (1)

Claim A method of obtaining a complex fertilizer, including the decomposition of phosphate raw materials with phosphoric acid in the presence of ammonium sulfate, filtering the pulp with the release of the liquid phase and its processing into ammophos, processing the solid phase with sulfuric acid, returning the resulting phosphoric acid to the decomposition of phosphate raw materials, characterized in that reducing the consumption of sulfuric acid and improving the filtration performance of the pulp, while maintaining the quality of the product ammonium sulfate is pre-mixed with phosphoric acid and the resulting admixture of ⁵ 1500640 ⁶ give 10-40Ζ phosphate for decomposition the rest of the raw material is decomposed raw materials from its total, and returnable phosphoric acid ₀ g 1 Ί Experience Apatite consumption by processing stages in H ₃ PO ₄ ^ Feed Method (ΝΗ ₄ ) ^ 8Ο ₄ and H ₃ P0 ₄ Filtration performance of the pulp after processing, t / m ^2, days Consumption N ₂ 80 ₄ kg / t apatite I II According to the proposed one five 95 Together 88 710 2 ten 90 1 16 670 3 20 ' 80 121 660 four thirty 70 107 666 five 40 60 94 674 6 50 50 81 718 According to well-known soba 7 100 0 Apart 46 727 Comparative * eight 100 0 Together 76 721