SU1535864A1 - Method of producing complex fertilizer - Google Patents

Abstract

The invention relates to a technique for producing long-acting fertilizers from phosphate raw materials and extraction phosphoric acid containing polyphosphates, and contributes to improving the quality of the product by increasing the amount of nutrients. Phosphate raw materials are pre-treated with ammonium phosphate pulp with a pH of 0.5–1.2 at W: T = 2–3: 1 and stirring is carried out for 10–30 min, followed by the introduction of ammonium phosphate pulp with a pH of 1.5–4 until reaching W: T = 4-6: 1 and stirring for 20-40 minutes. The resulting mass is granulated and calcined. The method makes it possible to reduce the amount of phosphorus-containing reagent used in the process by a factor of 2 to 3, while increasing the amount of nutrients by 6 to 8%. 1 tab.

Description

The invention relates to a technique for the production of long-acting fertilizers from phosphate raw materials and extraction phosphoric acid containing polyphosphates.

The aim of the invention is to improve the quality of the product by increasing the total amount of nutrients.

Example 1. 195.5 kg of extraction phosphoric acid (24% P205) are ammoniated with 4.5 kg of NH3 to a pH of 0.5 and mixed with 100 kg of Karatau phosphate (25.7% of P, jOs). The resulting mass was mixed for 10 minutes at 80CC and mixed with 200 kg of ammoniated pulp with a pH of 2 (187.3 kg of extraction phosphoric acid, neutralized with 12.7 kg of NH ,,). Preparation of

mass with a ratio of stirred for 40 minutes, granularit, dried and calcined The product (207 kg) contains Pa05, wt.%: total. 56.7 and N 4.1. The amount of nutrients 60.8%.

Example 2, 283.7 kg of extraction phosphoric acid are ammoniated with 17.2 kg of ShZ to pH 1.2 and mixed with 100 kg of Karatau phosphate. The resulting mass with the ratio G: T "3: 1 is stirred for 30 minutes at 80 ° C and mixed with 300 kg of ammoniated pulp with a pH of 2 (281 kg of extraction phosphoric acid, neutralized with 19 kg of NH3). The resulting mass with the ratio W: T 6: 1 is mixed for 20 minutes, granulated, dried and calcined. .

The product (280 kg) contains PX ° S wt.%: Total. 57.5; N 4.6. The amount of nutrients is 62.1%.

SP

00

sp oo

OE

Example 3. 239 kg of phosphoric acid extraction are ammoniated with 11 kg of NH, to a pH of 1 and mixed with 100 kg of Karatau phosphate. The resulting mass with a ratio of 5: 1 is stirred for 20 minutes at 80 ° C and mixed with 250 kg of ammoniated pulp with pH 2 (234.8 kg of extraction phosphoric acid neutralize 15.2 kg of NH3). The resulting mass is stirred for 30 minutes, granulated, dried and washed with

The product (245 kg) contains, wt%: P.jOs total. 56.9 and N 5.3. The amount of nutrients is 62.2%.

The table lists examples of the process within the proposed parameters (examples 1-6) and for their lower and upper levels (examples 7-16).

A decrease in the pH of the phosphorus-containing reagent to 0.3 (Example 7) at the pretreatment stage leads to a decrease in the performance of the process due to the opening of impurities of phosphate raw materials and the formation of iron and aluminum phosphates, which are not converted to polyphosphate.

An increase in the pH of the phosphorus-containing reagent to 1.5 (Example 8) at the pretreatment stage leads to a decrease in the total content due to the incomplete transfer of the phosphorus-containing mineral in the phospholite to the mono-calcium phosphate.

A decrease in the L: T ratio at the pretreatment stage of the phosphorus-containing reagent to 1.5: 1 (Example 9) leads to a deterioration in the quality of the product due to the low degree of phosphate exposure.

An increase in the W: T ratio at the pretreatment stage of the phosphate raw material to 3.5 (Example 10) leads to a decrease in the process indicators due to a change in the water balance and a decrease in the process indicators at the calcination stage.

Reducing the processing time in the first stage of the process to 5 minutes (Example 11) reduces the performance of the process due to the low degree of phosphate exposure.

An increase in the duration of phosphorite treatment with a phosphorus-containing reagent to 35 minutes (Example 12) leads to a deterioration in the quality of the product and is impractical due to the increase in the equipment object and the duration of the process.

A decrease in the W: T ratio in the second stage of the process to 3.5: 1 (Example 13) leads to a decrease in the performance of the process due to the lack of phosphorus-containing reagent.

Increasing the W: T ratio in the second stage of the process to 6.5: 1 (Example 14) reduces the process performance due to a decrease in the degree of polycondensation due to the prevalence of the mono-ammonium phosphate.

Reducing the duration of mixing in the second stage of the process to 15 minutes (Example 15) leads to deterioration of the process due to the low degree of opening of phosphorite.

An increase in the duration of mixing in the second stage of the process to 45 minutes (Example 16) is economically inexpedient and leads to retro-gradation of water-soluble phosphates and, as a result, to a decrease in the degree of polycondensation during calcination.

In the proposed method, the amount of phosphorus-containing reagent used in the process is reduced by a factor of 2-3. At the same time, the product is of higher quality - the amount of nutrient substances is 6-8% higher

Claims (1)

Invention Formula A method of obtaining a complex fertilizer, including treating phosphate raw materials with ammonium phosphate pulp with a pH of 1.5-4, granulation and calcining the resulting product, which is different from the fact that, in order to improve the quality of the product by increasing the amount of nutrients, phosphate raw materials pretreated with ammonium phosphate pulp with a pH of 0.5-1.2 at W: T (2-3): 1 and stirring for 10-30 minutes, and ammonium phosphate pulp with a pH of 1.5-4 is introduced until W: T (4-6): 1 and stirring lead 20-40 min0