SU1209601A1 - Method of producing phosphoric acid - Google Patents

Description

The invention relates to a method for producing phosphoric acid in the dihydrate mode and can be used in the production of mineral fertilizers.

The purpose of the invention is faster filtration rates in the processing of poor phosphate feedstock.

Example 1 To the extractor, 231 t / h of circulating phosphoric acid with a concentration of 14.5%, 51 t / h of sulfuric acid with a concentration of 93%, 64 t / h of phosphorite, containing 24.5% of P, and 2.5% are delivered. MgO (phosphate-siliceous shales), 13.75 kg / h of higher fatty acids of fraction C; j-Ci, (IVH), and 13.75 kg / h of higher fatty alcohols of fraction, (ILV Ratio of IVH: LCH 1: 1 , the total consumption of 0.5 kg / ton of phosphorite. Decomposition is carried out at 80 ° C and the ratio of liquid and solid phases in the pulp is 2.5: 1, the reaction time of the reactants is 4 hours. The production quantity of the pulp is 324.8 tons / h. filtration, where at the vacuum e 0.5 ata (vacuum is similar to known methods) with

Characteristics of the method of obtaining

- 500

Only BZHK

(C-C ,,.,) 580

0.5: 1600

1: 1700

3: 1750

5: 1750

6: 1600

countercurrent washing of the precipitate with water in the amount of 102.4 t / h receive 62 t / h of extraction phosphoric acid with a concentration of 20%, 92.8 t / h of phosphogypsum and 231 t / h of reverse phosphoric acid. Filtration capacity 700 dry calcium sulphate dihydrate.

The increase in the filtration rate of calcium sulfate dihydrate is due to the production of larger crystals, the growth of which is affected by

the introduction of a mixture of fatty acids and alcohols. Fatty acids and alcohols, adsorbing on the facets of calcium sulfate dihydrate crystals, change their habit, crystals

take the form: close to isometric, the ratio of the length of the crystal to the width is (1-2): 1, instead of (3-5): 1, without the addition of this mixture or with only

limit fatty acids.

The data on the effect of the weight ratio of IVH and VGS on the filtration rate are presented in Table 1.

Table 1

sovoy soot - I Speed

SIVI: VZhS filtering

calcium sulphate, kg / m-h

As can be seen from the table, 1, the use as an additive of a mixture of high-fatty acids and VZhS in the ratio (1-5): 1 significantly increases the filtration rate, which increases from 500 to 700-750 kg / m - h.

Example 2. In the extractor serves 242.6 t / h of circulating phosphoric acid with a concentration of 14.5% P7.05, 53.6 t / h of sulfuric acid with a concentration of 93%, 67 t / h of phosphorite composition according to example 1, 167.5 kg / hr of the residue from the distillation of paraffin consisting of the higher fatty acids of the Cit-Czs fraction (a mixture of fatty acids of the general formula R-COOH, where R varies from

, g

to Cji,) and

33.5 kg / h of higher fatty alcohols of fraction C, -Shchs, (mixture of fatty alcohols of general formula R-OH, where R varies from to Hjg).

Typical dihydrate process on phosphorites (24.5% 2.5% MgO)

The known method with reference to the phosphorites composition according to example 1

Proposed

12

3

four

five

6

7

209601

The ratio of high fatty acids: VZhS 5: 1, the total consumption of 3.0 kg / t of phosphorite. The decomposition is carried out at and the ratio of the liquid and solid phases in the pulp is 5 pe 2.5: 1, the reaction time of the reactants is 4 hours. The production quantity of pulp 340 t / h is fed to the stage of vacuum filtration, where under vacuum 0.5 at the countercurrent washing of the precipitate with water in the amount of 107.2 t / h, 75.6 t / h of extraction phosphoric acid with a concentration of 20% PiOs, 97.2 t / h of dry phosphoric gypsum and 242.6 t / h of recycled phosphoric acid are obtained. Filtration capacity 730 hours of dry calcium sulfate dihydrate.

ten

15

The data on the effect of the consumption of additives on 2Q phosphogypsum filtration rate are given in Table 2.

Table 2

500

WITH, )

1.0

ZhS 0.4 + 0.03 l, 25 + 0.25 0.5 + 0.5 2.5 + 0.5 1.0 + 1.0

3.75 + 1.25 4.0 + 3.0

580

550 700 700 730 740 750 750

It is seen from Table 2 that the introduction of 0.5–5 kg per ton of phosphorite as a mixture of fatty acids and alcohols in the amount of 0.5–5 kg permits an increase in the filtration rate of phosphogypsum. up to 700-750. A further increase in the consumption of components is impractical, since the filtration rate remains at the same level.

Example 3. The extractor serves 250 t / h of circulating phosphoric acid with a concentration of 14.5% P7.0 |;, 55.2 t / h of sulfuric acid with a concentration of 93%, 69 t / h of phosphate of the composition of example 1, 259 kg / h higher fatty acids fraction and 86 kg / h of higher fatty alcohols fraction C ,,. The ratio VZHKgVZHS 3.0: 1, the total consumption of 5.0 kg / ton of phosphate. The decomposition is carried out at 80 ° C and the ratio of the liquid and solid phases in the pulp is 2.5: 1, the reaction time of the reactants is 4 hours. The production quantity of the pulp is 350 tons / hour and is fed to the vacuum filtration stage

where, with a vacuum of 0.5 at, with a backwash of the precipitate with water in the amount of 110.4 t / h, 77.8 t / h of extraction phosphoric acid with a concentration of 20% is obtained,

100 t / h of dry phosphohysis and

250 t / h of circulating phosphoric acid. Filtration capacity 750 kg / m – h dry calcium sulfate dihydrate.

Claims (3)

1. METHOD FOR PRODUCING PHOSPHORIC ACID, including the processing of phosphate feedstock with reverse phosphoric and sulfuric acids in the presence of an additive of higher fatty acids, followed by separation of the product from the precipitate of calcium sulfate dihydrate by filtration, washing and washing water to treat phosphate feedstock as reverse phosphoric acid, characterized the fact that, in order to increase the rate of sludge filtration when using poor phosphate raw materials, pre- is additionally added to the processing of phosphate raw materials. individual higher fatty alcohols with a mass ratio of higher fatty acids and higher fatty alcohols (1-5): 1. 2. The method according to claim 1, characterized in that the ultimate higher fatty acids and alcohols are introduced in a total amount of 0.55.0 kg / t of raw material. 3. The method according to claim 1, characterized in that when processing use the ultimate higher fatty acids and alcohols with the number of carbon atoms 12-25. SU., „1209601> 1 1209601 2