SU1477677A1 - Method of producing wet-process phosphoric acid - Google Patents

Abstract

This invention relates to methods for producing phosphoric acid from lean phosphate rock and can be used in the manufacture of mineral fertilizers. The aim of the invention is to reduce the consumption of surface-active substances (surfactants), maintaining high process performance. Phosphoric acid is obtained by treating raw materials with circulating phosphoric and sulfuric acids to form pulp, where surfactants are introduced before filtration, as which the product of sulfonation of electrode production waste is used. The surfactant contains arylsulfonic acids, polycyclic and heterocyclic nitrogen, sulfur and oxygen-containing compounds. maintain within 0.021-0.042% relative to calcium sulphate. Phosphate acid with a concentration of 21.20- 22.40% P ₂ O _{5 is} obtained, the yield is R ₂ O ₅ , 95.4-97.4%, the FILTRATION SPEED of the PULP 502- 574.10 ^- 6 MS ^- 1, the SPECIFIC SEDIMENTATION FILTRATION 2.88-3.18.10 ¹ 0 М ^- 2, REFRACTIVE RATE OF SUCTION 96.3-99.4%, HUMIDITY SEDIMATION 36-37.6%. 1 Z.P. FM, 2 TABL.

Description

one

The invention relates to a method for producing phosphoric acid (EPA) from a poor phosphate feedstock and can be used in the production of mineral fertilizers.

The aim of the invention is to reduce the consumption of surface-active substances (surfactants), maintaining high process performance.

Example 1. In the extractor serves 7.7 t / h of fossil Karatau (content, wt.%: Pa05 20.4; CaO 39.2; MgO 2.1; F 3.42; Fe 0.7; C0g 5.92 and insoluble residue 21.3) and decompose sulfuric and circulating phosphoric acid at 75 ° C. Before filtration, a 1% solution of surfactant (6.4 l / m3 of pulp) at the rate of 0.3044 kg / t of fossyr or 0.21 kg / t of phosphogypsum, which is 0.03 and 0.021 to the solid phase, is fed to the resulting pulp. , respectively.

Extraction phosphoric acid in terms of concentration contains 22.4 wt.% The washing ratio (K0) of P.OS reaches 99.4%, and the yield coefficient (Kv) is 97.4%. Without additives, technical parameters are

V v | OE

The following: Р; 05–20.4%, К0 93.12%, К „92%. Bullet filtration rate

rtbi is 574.2-10 ms 1, the specific volume resistance of the precipitate is 2.88 to 10% -2,

The surfactant is a sulfonic product, which is obtained by sulfonation of the resin-waste electrode production, containing a mixture of aromatic hydrocarbons, concentrated sulfuric acid. The general formula of surfactant is Ј, where Ar is an aromatic core consisting of a mixture of aromatic hydrocarbons (naphthalene, anthracene, phenanthrene) and polycyclic with aliphatic groups, and also heterocyclic sulfur; nitrogen and oxygen containing compounds

The resin sulphonation reaction — electrode production waste — takes place in the reactor with constant stirring with a stirrer for 120 minutes with steam heating to t 55 ° C - 1 hour and t 65 ° C - 1 hour. wt.%: C 63.09-65.89; II 5.0-5.13; 0 4.54-17.34; N 1.8-2.1; S 6,8-12,65.

According to a known method, the preparation of phosphoric acid is carried out by decomposition of the poor phosphate raw material in the dihydrate mode. Before filtration, a mixture of alkyl aryl sulfonic acids obtained by sulphurization of bottom refinery waste is introduced into the pulp as a surfactant. Surfactant consumption 0.21-1.20% relative to phosphogypsum. The coefficient of washing of phosphogypsum is 98.5-99.4%, the yield of g94.3-95%, the filtration rate of the pulp 469-660, the specific volume resistance of the precipitate 2.4-3.0.10 0. The concentration of phosphoric acid is 21.1-21.3%, the humidity of the washed calcium sulphate precipitate is 36.4-36, 8%. The elemental composition of the known surfactant, wt.%; C 84,10-88,14; II 53 22; 0 2.0-2.8; N 2.0-2.3; S 1.0-1, 58

In tab. 1 shows data showing changes in the filtration rate (W) of the specific volume resistance of the precipitate (g) calcium sulphate, the washing coefficients (K) and the yield (K 8) of the concentration of Pr05 in the product and the humidity of calcium sulphate (water f / g) from type and consumption of surfactants "

From the data table. 1 it follows that at the proposed interval of consumption

Q

0

„

0 5

five

The proposed surfactant process indicators are higher. They are also higher for this cost range for known surfactants.

In tab. Figure 2 shows the performance of the phosphoric acid production process for optimal consumption of the proposed and known surfactants.

Fosmuk Karatau, which serves as a raw material for the production of EPA, has a low P20 g content of 21% and a large amount of insoluble residues (21.3%). Highly dispersed clay particles are strongly peptized, impairing filtration, and the additives of the proposed surfactant promote the formation of floc aggregates from phos ™ phypsum and clay slimes, which improves the technological performance of EPA and phosphogypsum.

The possibility of reducing the consumption of surfactants is explained by the content in the composition of the proposed surfactants, in addition to naphthalene, anthracene, and phenzthrene 7 derivatives, also heterocyclic (five-, more-saturated aromatic hydrocarbons) polycyclic hydrocarbons. The presence of aromatic hydrocarbons leads to a greater flocculation effect than alkylaryl derivatives, and thus to a greater hydrophobization of the surface of the particles, which reduces the means to phosphogypsum.

you have invented

Claims (1)

1. A method of producing extraction phosphoric acid, which includes processing of poor phosphate feedstock phosphoric and sulfuric acid to form a slurry, introducing into it a surfactant before filtration, filtering the slurry with separating the product from calcium sulphate, rinsing characterized in that, in order to reduce the consumption of the surfactant while maintaining high process performances, odukt obtained resin by sulfonation - departing electrode production. 2) A method according to claim 1, characterized in that the consumption of the surfactant is maintained at 0.021-0.042% relative to calcium sulfate. Table 2 0.3 12.0 0.1 20,493,1292,043,4 58 22,499,497.436.0 100 21,399,095,036,4 2400 21.899,, 241.0