RU2385885C1 - Pyridine ionite for sorbing uranium from solutions and pulp - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: present invention relates to sorption hydrometallurgy of uranium. Described is a pyridine ionite based on a copolymer of styrene and divinylbenzene for sorbing uranium from solutions and pulp, distinguished by that the initial polymer matrix of the ionite additionally contains methacrylic acid in amount of 3.0-6.0 wt %.

EFFECT: obtaining an ionite with improved desorption characteristics; improved cost-performance ratio of the sorption-desorption process of extracting uranium from a solution.

2 cl, 3 tbl, 2 ex

Description

The inventive ion exchanger relates to sorption hydrometallurgy of uranium and can be used to extract uranium from solutions and pulps.

Pyridinium ion exchangers are known for sorption of uranium from sulfuric acid solutions and pulps based on styrene-DVB copolymers: AMP, AMP-p and AMP-1 (Reference "Ion-exchange materials for hydrometallurgy, wastewater treatment and water treatment." Ed. By Acad. B. N. Laskorina. M., VNIIKhT, 1989; Handbook of Uranium Geotechnology. Edited by D. I. Skorovarov. M: Energoatomizdat, 1997, p. 385-404; Yu.V. Nesterov. Ionites and ion exchange. Sorption technology in the extraction of uranium and other metals by underground leaching. M., 2007, S. 39-40, S. 233-316). In addition, vinyl pyridine ion exchangers for sorption of uranium based on copolymers of 2-methyl-5-vinylpyridine and DVB are known: VP-1Ap, VP-3Ap, VP-4Ap (B.N. Laskorin, G.N. Nikulskaya, K.F. Perelygina. Anionites based on vinylpyridines // Production and processing of plastics and synthetic resins. M .: issue NIIPM. 1977, No. 16, p.16-19; Reference "Ion-exchange materials for hydrometallurgy, wastewater treatment and water treatment." Edited by Academician B.N. Laskorin. M., VNIIKhT, 1989; Uranium Chemistry. Edited by B.N. Laskorin. M: Nauka, 1981, p. 58-63).

The disadvantages of the above ion exchangers are insufficiently high weight (mg / g) and bulk (mg / cm ³ ) uranium capacities, the need to use highly concentrated solutions of acids and salts for uranium desorption. This leads to a large consumption of sorbents and reagents during the processing of sulfate solutions and pulps and, in general, to a decrease in the efficiency of this process.

The closest in technical essence and the achieved result when using is pyridinium ion exchanger based on a copolymer of styrene and divinylbenzene of the AMP brand, which is used for sorption of uranium from solutions and pulps (Uranium Chemistry. Edited by B.N. Laskorin. M .: Nauka, 1981 p. 58-63).

The disadvantages of this ion exchanger are:

- a relatively low capacity for uranium;

- the long duration of contact of a uranium-ion exchanger with an eluent solution, for example, a nitrate sulfate solution, in uranium desorption operations;

- a large volume (yield) of the product fraction of the desorbate;

- a relatively high residual ionite capacity for uranium after its desorption.

The technical result of the invention is the elimination of the above disadvantages.

The technical result is achieved by the fact that methacrylic acid is additionally introduced into the composition of the pyridinium copolymer in an amount of 3.0-6.0 wt.%, Moreover, it is introduced into the ion exchanger at the stage of preparation of the copolymer and / or by treating the copolymer with mixtures of metered amounts of the starting monomers followed by polymerization copolymer processing products.

The inventive ion exchanger is prepared as follows.

The low-cross-linked styrene or acrylate-styrene copolymer, which is the initial (base) polymer matrix, is prepared by suspension copolymerization in an aqueous solution of potato starch monomer mixture consisting of styrene, technical divinylbenzene (DVB), ethyl styrene (ES), and benzene peroxide polymerization initiator and a pore former, or a monomer mixture comprising styrene, DVB, ES, PB, a pore former and methacrylic acid (MAA).

The obtained base matrix is treated with a mixture of dosed amounts of styrene, DVB, ES, PB and MAK and the product is subjected to secondary polymerization under certain conditions. Such processing of the base matrix followed by polymerization of the treatment product can be carried out once or twice.

Further steps in the preparation of pyridinium ion exchanger include chloromethylation of styrene, DVB and MAK copolymers and amination of chloromethylated copolymers with pyridine.

The obtained ion exchanger after conversion to the SO ₄ form is used for sorption of uranium.

Example 1. For sorption of uranium from a sulfate productive solution of underground leaching (PV), containing, g / l: 0.05 uranium; 1.3 iron (Fe ²⁺ + Fe ³⁺ ); 0.2 calcium; 0.08 magnesium; 0.07 silicon; 2.1 aluminum; 3,7 sulfuric acid, pyridinium ion exchangers with different MAA content in the polymer matrix are used. For comparison, the sorption of uranium from the same solution is carried out by AMP pyridinium anion exchange resin not containing MAK in the copolymer (prototype). Uranium is sorbed under static conditions, contacting the ion exchangers in the SO ₄ form with the solution for 20 hours with constant mechanical stirring, the ratio of the volumes of the solution and the ion exchanger is 3000: 1 and a temperature of 18-20 ° C. Then the ion exchanger is separated from the solution, washed with water, dried at a temperature of 80 -85 ° C. In dry ion exchangers after their decomposition by the method of "wet burning" determine the uranium content. Data on the weight (mg / g) and volumetric (mg / ml) capacities of the tested ion exchangers are given in Table 1.

The weight capacity for uranium (mg / g) of the inventive Rossion ion exchanger with a MAA content in the copolymer of 3.0-6.6 wt.% Exceeds the capacity of the prototype. At the same time, the volumetric capacity of the prototype (mg / cm ³ ), which determines the parameters of the technological process of sorption of uranium, is significantly lower than the volumetric capacity of the claimed ion exchanger with a MAK content of 3.0-6.0 wt.%. An increase in the content of MAA in excess of 6.0 wt.% Leads to a significant increase in the specific volume of the ionite swollen in the processed solution and, as a result, to a sharp decrease in its volumetric capacity, which is unacceptable for technological purposes.

Table 1 Comparative characteristics and uranium capacity of samples of the inventive pyridinium ionite during sorption of uranium from productive solutions of PV Ionite Characteristics Grade and number of sample anion Rossion 609 Rossion 610 Rossion 611 Rossion 62 Rossion 612 AMP prototype IAC Content 2,8 4.7 5.72 3.0 6.6 0,0 in copolymer, wt.% Specific volume, cm ³ / g 2,3 2,4 2.5 2.2 3,5 2,4 when swelling in productive solution Uranium capacity, mg / g 46.2 56.4 56.3 74,4 55,2 50,5 Uranium capacity, mg / cm ³ 20,0 23.5 22.5 33.8 15.8 21.0

Similar results were obtained during the sorption of uranium by the claimed ion exchanger from sulphate of sulfate from leaching of uranium ores containing, g / l: 1.0 uranium; 0.23 silicon; 4.0 iron (II); 3.5 iron (III); 0.2 calcium; 2.0 aluminum; 0.5 mg and having a pH of 1.7. Sorption was carried out in a static mode under the above conditions.

The data obtained are given below (table 2).

table 2 Uranium capacity of samples of the inventive pyridinium ion exchanger upon sorption of uranium from pulps Uranium ionite capacity Make and number of sample of anion exchange resin Rossion 609 Rossion 610 Rossion
611 Rossion 62 Rossion 612 AMP prototype Weight, mg / g 166.0 206 198 255 168.7 130.0 Volumetric, mg / cm ³ 72,2 85.8 79.2 116 48,2 54,2

Thus, the introduction of methacrylic acid in the amount of 3.0-6.0 wt.% Pyridinium ion exchanger into the polymer matrix makes it possible to increase the weight and volumetric capacity of the ion exchanger on uranium during its sorption both from solutions and from pulps, to improve the performance of the sorption process, reduce the one-time load of ion exchanger and reduce the number of sorption apparatus.

The introduction of MAK in the composition of the claimed ion exchange resin allows not only to increase its capacity for uranium, but also to improve the technological parameters of the process of desorption of uranium from ion exchange resin in comparison with the prototype.

Example 2. From the samples of the claimed ion exchange resin saturated with uranium from a productive PV solution of the above composition, uranium is desorbed under dynamic conditions by passing a stripping solution through a 0.5-meter-high layer of ion exchange resin in a column at a rate of 1 volume of solution to the volume of sorbent per hour at a temperature of 20 ° C. The desorbate flowing from the column is selected in fractions of 0.5 volume to the volume of sorbent in the column and the uranium content in each fraction is determined. Based on the data obtained, the output uranium desorption curve is constructed, which determines the approximate yield (volume) of the commodity fraction of the desorbate and the expected concentration of uranium.

As a stripping solution using a 10 percent solution of ammonium nitrate with the addition of 1% sulfuric acid (100 g / l NH ₄ NO ₃ + 10 g / l H ₂ SO ₄ ).

Under similar conditions, uranium is desorbed with the same solution from the prototype - AMP pyridinium ion exchanger.

The data obtained are presented in table.3.

Table 3 Comparative technological indicators of the process of desorption of uranium from samples of the claimed ion exchange resin and AMP Technological indicator Make and number of sample of anion exchange resin Rossion 610 Rossion 611 Rossion 62 AMP prototype The capacity of saturated ion exchanger for uranium, mg / g 56.4 56.3 71.2 50,5 The capacity of saturated ion exchanger for uranium,
mg / cm ³ 23.5 22.5 32.9 21.0 The required duration of contact of the ion exchanger with a desorption solution, h 10-12 15-18 7-10 15-20 The volume (output) of the commodity fraction of the desorbate, the volume / volume of ion exchanger 2.0 2.5-2.7 2.0-2.5 2.5-3.0 The residual capacity of the ion exchange resin for uranium after desorption, mg / cm ³ 0.44 0.3 0.23 1,2 The expected (estimated) concentration of uranium in the commodity fraction of the desorbate, g / l 11.5 8.2-8.9 13.1-16.3 6.8-8.2

Judging by the above data, the claimed ion exchanger in comparison with the prototype has significantly better desorption characteristics, which provides:

- the best kinetics of uranium desorption;

- less residual capacity for uranium after desorption;

- less volume (yield) of the product fraction of the desorbate;

- a higher concentration of uranium in the product desorbate.

All of the above allows to generally improve the technical and economic indicators of the sorption-desorption process of uranium extraction from solution:

- reduction of a one-time load of ion exchanger and its consumption;

- reduction of reagent consumption for uranium desorption;

- reduction in the number of technological equipment.

Claims (2)

1. Pyridinium ion exchanger based on a copolymer of styrene and divinylbenzene for sorption of uranium from solutions and pulps, characterized in that methacrylic acid is additionally added to the composition of the initial polymer matrix of the ion exchanger in an amount of 3.0-6.0 wt.%. 2. Pyridinium ion exchanger according to claim 1, characterized in that methacrylic acid is introduced into the ion exchanger at the stage of obtaining the copolymer and / or by treating the copolymer with mixtures of metered amounts of the starting monomers followed by polymerization of the copolymer processing products.