RU2523892C2 - Method of extracting rhenium from uranium-containing solutions - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to sorption hydrometallurgy of uranium and rhenium and can be used to extract rhenium from solutions and pulp. The method of extracting rhenium from uranium-containing solutions includes sorption of rhenium on anions. Before sorption, fulvic acids are added to the solution until concentration thereof in the solution reaches 25-300 mg/l. Rhenium sorption is carried out at solution pH 2.8-3.5. Sorption is carried out on weakly basic and strongly basic anionites.

EFFECT: improved sorption/desorption properties, high cost/performance ratio of the sorption sorption/desorption process of extracting rhenium from a uranium-containing solution.

2 cl, 6 tbl, 6 ex

Description

The present invention relates to sorption hydrometallurgy of rhenium and uranium, in particular to a method for extracting rhenium from uranium-containing solutions.

A known sorption method for the extraction of rhenium and uranium and their subsequent separation using strongly basic anion exchangers, for example, AMP, AMP. Collective sorption of rhenium and uranium is carried out from sulfuric acid solutions of underground leaching of uranium ores, the separation of these metals occurs by sequential desorption of uranium first, then rhenium. Uranium is eluted with sulfuric acid solutions (10-15% sulfuric acid), and rhenium periodically with nitrate solutions (80-90 g / l of nitrate ions and 4-4.5% nitric acid). (Underground leaching of polyelement ores / N.P. Laverov, I.G. Abdulmanov, K.G. Brovin et al .; Edited by N.P. Laverov. - M.: Publishing House of the Academy of Mining Sciences, 1998. - 446 p. - S.222-223, 226-227; Yu.V. Nesterov, Ionites and ion exchange. Sorption technology for the extraction of uranium and other metals by underground leaching. - M.: UNICORN-IZDAT, 2007. - 480 p. - S.326-327).

The disadvantages of the above method include the loss of rhenium during sorption, aimed at achieving the completeness of uranium extraction, the need to use nitrate solutions for rhenium desorption, which requires additional operations to obtain a marketable rhenium product - ammonium perrenate, the periodicity of the rhenium desorption process. This leads to a decrease in the efficiency of the sorption extraction of rhenium.

The closest in technical essence and the achieved result when using is a method for extracting rhenium from uranium solutions with weakly basic ion-type resins AN-21 and Purolite A 170. After combined sorption of rhenium and uranium, rhenium is desorbed with an ammonia solution (with a concentration of 3 mol / l), and then after water washing the sorbent elute uranium with a solution of sulfuric acid (100 g / l) or acidified ammonium nitrate (pH 0.45) (ZS Abisheva, AN Zagogodnyaya. Rhenium in Kazakhstan. 7 ^th International Symposium on Technetium and Rhenium - Science and Utilization. Book of Proceedings. July 4-8, 2011, Moscow, Russia (Eds. KE German, BF Myasoedov, GE Ko dina, A. Ya. Maruk, ID Troshkina), Moscow: Publishing House GRANITZA, 2011 .-- 460 p. - P.214).

The disadvantages of this method are the pollution of rhenium-saturated anion exchange resin with uranium due to the joint sorption of metals. This leads to the need for an additional operation of uranium desorption, which is accompanied by an increased consumption of reagents, an increase in the cost of equipment for elution of uranium.

The technical result of the invention is to increase the selectivity of rhenium ion exchangers during sorption from uranium-containing solutions, accompanied by a decrease in the uranium content in the sorbents.

The technical result is achieved by the fact that a solution of fulvenic acid is added to the rhenium-uranium-containing solution before sorption until a concentration of 25–300 mg / L is created in the solution, and rhenium is sorbed at a pH of 2.8–3.5. Sorption is carried out on strongly basic and weakly basic anion exchangers. The concentration of fulvenic acids in the solution is mainly 50 ÷ 100 mg / L.

When the concentration of fulvenic acid is less than 25 mg / l, the decrease in the distribution coefficient of uranium is negligible. Obtaining solutions of fulvenic acids with a concentration of more than 300 mg / l makes the process more expensive, while the separation coefficient of rhenium and uranium does not change.

At a pH of less than 2.8, the carboxyl groups of fulvenic acids are weakly dissociated, which leads to a slight interaction of uranium with them and a decrease in the separation coefficients of rhenium and uranium. At a pH value of more than 3.5, precipitation of uranium-fulvate complexes occurs.

The implementation of the process of extracting rhenium from uranium-containing solutions is illustrated by the following examples.

Example 1

For sorption of rhenium from a sulfate solution containing, mg / l: 10 uranium; 10 rhenium, 10,000 sulfate ions, pH 2.8 use a weakly basic ion exchanger with secondary amino groups in a polymer matrix (Purolite A 170). For comparison, the sorption of rhenium from the same solution was carried out in the absence of fulvenic acids on the same ion exchanger (prototype). Rhenium is sorbed under static conditions. After 4 contacts of the anion exchange resin 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 (ml: g) and a temperature of 18 ÷ 20 ° C to an equilibrium concentration of uranium and rhenium equal to their concentration in the initial solution, the weight capacity of the anion exchange resin for rhenium and uranium was determined and their distribution coefficients were calculated (Table 1). According to the distribution coefficients, the separation coefficient of rhenium and uranium was calculated as the ratio of their distribution coefficients (Table 1).

Table 1. The concentration of fulvenic acids, mg / l Sorption capacity of rhenium ion exchanger, mg / g Uranium ionite sorption capacity, mg / g The distribution coefficient of rhenium, l / g Uranium distribution coefficient, l / g The separation coefficient of rhenium and uranium, S _{Re / U} 0 (prototype) 42.7 10,2 4.27 1,02 4.2 25 42,4 7.6 4.24 0.76 5,6 fifty 42.7 ZD 4.27 0.31 13.8 one hundred 42,2 0.8 4.22 0.08 52.8 300 41.9 0.4 4.19 0.04 104.8

Example 2

For sorption of rhenium from a sulfate solution containing, mg / l: 10 uranium; 10 rhenium, 10,000 sulfate ions, pH 3.0 use a weakly basic ion exchanger with secondary amino groups in a polymer matrix (Purolite A 170). For comparison, the sorption of rhenium from the same solution was carried out in the absence of fulvenic acids on the same ion exchanger (prototype). Rhenium is sorbed under static conditions. After 4 contacts of the anion exchange resin 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 (ml: g) and a temperature of 18 ÷ 20 ° C to an equilibrium concentration of uranium and rhenium equal to their concentration in the initial solution, the weight capacity of the anion exchange resin for rhenium and uranium was determined and their distribution coefficients were calculated (Table 2). According to the distribution coefficients, the separation coefficient of rhenium and uranium was calculated as the ratio of their distribution coefficients (Table 2).

Table 2. The concentration of fulvenic acids, mg / l Sorption capacity of rhenium ion exchanger, mg / g Uranium ionite sorption capacity, mg / g The distribution coefficient of rhenium, l / g Uranium distribution coefficient, l / g The separation coefficient of rhenium and uranium, S _{Re / U} 0 (prototype) 45.7 9.8 4,57 0.85 4.6 25 45.4 6.6 4,54 0.66 6.9 fifty 45.7 2.1 4,57 0.21 21.8 one hundred 45,2 0.5 4,52 0.05 90,4 300 44.9 0.4 4.49 0.04 112.3

Example 3

For sorption of rhenium from a sulfate solution containing, mg / l: 10 uranium; 10 rhenium, 10,000 sulfate ions, pH 3.5 use a weakly basic ion exchanger with secondary amino groups in a polymer matrix (Purolite A 170). For comparison, the sorption of rhenium from the same solution was carried out in the absence of fulvenic acids on the same ion exchanger (prototype). Rhenium is sorbed under static conditions. After 4 contacts of the anion exchange resin 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 (ml: g) and a temperature of 18 ÷ 20 ° C to an equilibrium concentration of uranium and rhenium equal to their concentration in the initial solution, the weight capacity of the anion exchange resin for rhenium and uranium was determined and their distribution coefficients were calculated (Table 3). According to the distribution coefficients, the separation coefficient of rhenium and uranium was calculated (Table 3).

Table 3. The concentration of fulvenic acids, mg / l Sorption capacity of rhenium ion exchanger, mg / g Uranium ionite sorption capacity, mg / g The distribution coefficient of rhenium, l / g Uranium distribution coefficient, l / g The separation coefficient of rhenium and uranium, S _{Re / U} 0 (prototype) 51.1 11.6 5.11 1.16 4.0 25 46.7 11.7 4.67 1.17 4.4 fifty 42.1 6.5 4.21 0.65 6.5 one hundred 40.6 2.9 4.06 0.29 14.0 300 38.7 0.8 3.87 0.08 48,4

Example 4. For sorption of rhenium from a sulfate solution containing, mg / l: 10 uranium; 10 rhenium, 10,000 sulfate ions, pH 2.8 use a strongly basic ion exchanger (Purolite A 600). For comparison, sorption of rhenium from the same solution was carried out in the absence of fulvenic acids on the same ion exchanger. Rhenium is sorbed under static conditions. After 4 contacts of the anion exchange resin 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 (ml: g) and a temperature of 18 ÷ 20 ° C to an equilibrium concentration of uranium and rhenium equal to their concentration in the initial solution, the weight capacity of anion exchange resin for rhenium and uranium was determined and their distribution coefficients were calculated (Table 4). According to the distribution coefficients, the separation coefficient of rhenium and uranium was calculated (Table 4).

Table 4. The concentration of fulvenic acids, mg / l Sorption capacity of rhenium ion exchanger, mg / g Uranium ionite sorption capacity, mg / g The distribution coefficient of rhenium, l / g Uranium distribution coefficient, l / g The separation coefficient of rhenium and uranium, S _{Re / U} 0 37.3 21.8 3.73 2.18 1.7 25 37.1 19.0 3.71 1.90 1.9 fifty 37.1 13.5 3.71 1.35 2.7 one hundred 37.1 10,4 3.71 1,04 3.6 300 35.1 8.4 3,51 0.84 4.2

Example 5. For sorption of rhenium from a sulfate solution containing, mg / l: 10 uranium; 10 rhenium, 10,000 sulfate ions, pH 3.0 use a strongly basic ion exchanger (Purolite A 600). For comparison, sorption of rhenium from the same solution was carried out in the absence of fulvenic acids on the same ion exchanger. Rhenium is sorbed under static conditions. After 4 contacts of the anion exchange resin 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 (ml: g) and a temperature of 18 ÷ 20 ° C to an equilibrium concentration of uranium and rhenium equal to their concentration in the initial solution, the weight capacity of the anion exchange resin for rhenium and uranium was determined and their distribution coefficients were calculated (Table 5). According to the distribution coefficients, the separation coefficient of rhenium and uranium was calculated (Table 5).

Table 5. The concentration of fulvenic acids, mg / l Sorption capacity of rhenium ion exchanger, mg / g Uranium ionite sorption capacity, mg / g The distribution coefficient of rhenium, l / g Uranium distribution coefficient, l / g The separation coefficient of rhenium and uranium, S _{Re / U} 0 38.3 20,0 3.83 2.0 1.9 25 37.6 18.0 3.76 1.8 2.1 fifty 37.8 12.5 3.78 1.25 3.0 one hundred 37.6 9.7 3.76 0.97 3.9 300 35,4 7.4 3,54 0.74 4.8

Example 6. For sorption of rhenium from a sulfuric acid solution containing, mg / l: 10 uranium; 10 rhenium, 10,000 sulfate ions, pH 3.5 use a strongly basic ion exchanger (Purolite A 600). For comparison, sorption of rhenium from the same solution was carried out in the absence of fulvenic acids on the same ion exchanger. Rhenium is sorbed under static conditions. After 4 contacts of the anion exchange resin 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 (ml: g) and a temperature of 18 ÷ 20 ° C to an equilibrium concentration of uranium and rhenium equal to their concentration in the initial solution, the weight capacity of anion exchange resin for rhenium and uranium was determined and their distribution coefficients were calculated (Table 6). According to the distribution coefficients, the separation coefficient of rhenium and uranium was calculated (Table 6).

Table 6. The concentration of fulvenic acids, mg / l Sorption capacity of rhenium ion exchanger, mg / g Uranium ionite sorption capacity, mg / g The distribution coefficient of rhenium, l / g Uranium distribution coefficient, l / g The separation coefficient of rhenium and uranium, S _{Re / U} 0 38.5 25.7 3.85 2,57 1.49 25 38.3 24.8 3.83 2.48 1,54 fifty 41.8 23,4 4.18 2,34 1.79 one hundred 37.6 20.1 3.76 2.01 1.87 300 36,2 18.3 3.62 1.83 1.98

Introduction to rhenium-uranium-containing solution of fulvenic acids in

the amount of 25 ÷ 300 mg / l allows not only to reduce the distribution coefficient of uranium in the ion exchange resin by 1.3 ÷ 17 times and to increase the separation coefficient of rhenium and uranium by 1.2 ÷ 20 times, but also to improve the technological parameters of the sorption-desorption of rhenium. At the same time, due to the low capacity of anion exchange resin for uranium observed during sorption under optimal conditions (Table 2), there is no need to conduct a uranium desorption operation, which leads to a decrease in reagent costs.

The inventive process in comparison with the prototype has significantly better sorption-desorption characteristics, which provides:

- lower sorption capacity of the ion exchange resin for uranium during sorption;

- a high degree of separation of rhenium and uranium at the sorption stage;

- a higher degree of purification of commodity rhenium desorbate.

The above allows us to improve the technical and economic indicators of the sorption-desorption process of extracting rhenium from a uranium-containing solution:

- reduced consumption of reagents for desorption;

- reduction in the number of technological equipment;

- reduction of capital and current costs for the process of elution of uranium.

Claims (2)

1. A method of extracting rhenium from uranium-containing solutions, including sorption of rhenium on anion exchangers, characterized in that fulvenic acids are added to the solution prior to sorption to a concentration of 25–300 mg / l in the solution, and rhenium is sorbed at a pH of 2.8 ÷ 3,5 on weakly basic and strongly basic anion exchangers. 2. The method according to claim 1, characterized in that the concentration of fulvenic acids is 50 ÷ 100 mg / L.