RU2613246C1 - Method for scandium extraction from productive solutions - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method includes sorption of rare earth metals solutions on a strongly acidic cation of porous structure with subsequent desorption of rare earth metals and eluate withdrawal. Next, scandium sorption is carried on a porous styrene-divinylbenzene carrier with an impregnated organophosphorus extractant, represented by di-(2,4,4-trimethylpentyl)phosphinic acid with addition of di-2-ethylhexyl phosphonic acid to obtain a return solution directed to leaching, and scandium desorption with eluate withdrawal.

EFFECT: increased processing efficiency of these solutions due to high sorbent selectivity for scandium extraction in the pH range of the return solution, reduced reagent consumption and improved quality of end scandium products.

4 cl, 3 tbl, 3 ex

Description

Technical field

The group of inventions relates to the field of chemistry and metallurgy, and in particular to the technology for extracting scandium from productive sulfate solutions formed during the extraction of uranium and other metals by underground leaching, an impregnated sorbent for the selective extraction of scandium from these productive solutions and the method for its preparation.

State of the art

Currently, a known method of extracting scandium from solutions, in particular from waste wet magnetic separation (MMS) of titanium-iron-vanadium ores. This waste is subjected to autopsy with sulfuric acid in order to transfer scandium into solution for subsequent extraction extraction. As an extractant, an equimolar mixture of methyl trioctylammonium bisulfate (MTOA) and di-2-ethylhexylphosphoric acid (D2EHPA) in a hydrocarbon diluent is used. The solutions after opening the sulfuric acid along with scandium contain impurities of iron, titanium, vanadium, aluminum, magnesium, silicon. The use of D2EHPA as the main component of the synergistic mixture is associated with its high extraction ability and selectivity for complex scandium cations, and the addition of MTOA salt to the extraction mixture facilitates the process of scandium reextraction with carbonate solutions (Stepanov S.I. et al. “Extraction extraction of scandium from sulfuric acid solutions of waste leaching from MMS ”// 2nd Russian Conference with international participation“ New Approaches in the Chemical Technology of Mineral Raw Materials ”, June 3-6, 2013, St. Pete burg, Vol. 1, pp. 135-136).

Known solid extractant (TWEX) for the extraction of scandium from solutions, synthesized by suspension copolymerization of styrene with divinylbenzene in the presence of tributyl phosphate extractant with the addition of copolymerization initiators (Korovin V.Yu. et al. Recycling of titanium-magnesium wastes with scandium extraction by solid extractant // , 1994, No. 3, pp. 25-31). However, a low selectivity of TWEX with respect to scandium cations was noted, since thorium, zirconium, titanium, and other impurities were extracted together with scandium in the TWEX phase, which led to the necessity of introducing cleanup operations, including pure extraction, into the general scheme and leading to irretrievable losses scandium. Among industrial extractants, the extractant di-2-ethylhexylphosphoric acid (D2EGFK) was widely used. This is due in no small part to the fact that its industrial synthesis is relatively simple, and the extractant is chemically and radiation stable. However, this reagent has limitations in use, due to the fact that arylphosphoric acids have too high distribution coefficients, which leads to difficulties in re-extraction and the need to use strong acids as re-extractants.

Closest to the claimed is a method of extracting scandium from a productive sulfate solution, disclosed in patent RU 2417267, publ. 04/27/2011, including adding to the productive solution, as a rule, with a pH of 1.2-1.5 an alkaline agent - ammonia water or caustic soda and adjusting its acidity to pH 2.5-3.0, extracting scandium from the solution on a solid extractant (TWEX) with selective scandium selectivity, scandium is re-extracted from the solid extractant by treating it with a 2-4 M solution of hydrofluoric acid, followed by precipitation of scandium fluoride, washing the solid extractant, and before reextraction the solid extractant is saturated with some concentrated th scandium solution obtained from the previous stripping, extraction and re-extraction is carried out in the same sorption apparatus, and the spent sulfuric acid solution and the solid washed with water extractant is recycled to extract scandium. The main disadvantage of this method is the high consumption of reagents to achieve the recommended pH range of 2.5-3.0, at which TVEKSom extracts scandium. A productive solution after leaching of uranium, directed to sorption of uranium on the strongly basic AMP anion exchange resin and obtained after quantitative sorption of uranium, has a pH value of 1.1-1.25. This solution is returnable in order to continue leaching of uranium, as well as other valuable components, including scandium, in order to transfer them into a productive solution. If the entire volume of daily productivity in a productive solution (more than 850 m ³ / h) is alkalinized to pH 2.5-3 to extract scandium, this will require a huge amount of alkaline agents - ammonia water and caustic soda. However, after extraction of scandium, this solution should become returnable, but for this it should be acidified again with sulfuric acid to a pH range of 1.1-1.25. Consequently, the cost of processing the final product of scandium becomes such that the process is unprofitable.

Another disadvantage of this method is the lack of purity of the final product based on impurities of rare earth metals. This is due to the fact that the productive solution contains iron (1.5 g / l) and aluminum (2.0 g / l), the concentration of which on average is 4,500 times higher than the content of scandium. It is known that with an increase in the pH of the solution, the absorption of iron and aluminum increases many times, and this creates the conditions for lowering the quality of the final product from rare earth impurities.

Solid extractant (TWEX) for the extraction of scandium from a productive solution and a method for its preparation are also disclosed in RU 2417267. TWEX is a styrene-divinylbenzene matrix with an organophosphorus compound obtained by suspension polymerization. As an organophosphorus compound, a mixture is used containing 40-60% of phosphoric acid di-2-ethylhexyl ester (DI2EGFK), 3-5% of azodiisobutyric acid dinitrile, 3-5% of aminomethylphosphonic acid. When using this TWEX, it was confirmed that the maximum sorption capacity for scandium was observed at pH 2.5-3, and in the range of pH 1.1-1.25, which is characteristic of a productive return solution, the capacity for scandium was almost minimal. Therefore, for the use of TWEX for sorption of scandium, the productive solution should be alkalinized to pH 2.5-3. However, such a correction of the pH of the returning productive solution to a more alkaline region, although it increases the sorption capacity of TVEKS according to scandium, but at the same time leads to a significant absorption of the main background rare earth impurities, namely iron (III) and aluminum (III).

Key technological indicators: extraction of scandium from the productive solution on TVEKS 98.6%; working equilibrium pH of the solution after contacting the productive solution with TWEX - 2.5-3.0; the scandium content in the productive solution is 0.75-0.85 mg / l; the transmission rate of the productive solution through the dense layer of TWEX in the column in the direction from top to bottom is 2 beats. about. in hour; the content of scandium in the reextract is 0.25 g / l; the content of impurities of iron and aluminum in the reextract, g / l: 4.5 iron and 3.8 aluminum. Losses of scandium are mainly attributable to scandium sorption operation by TVEX and account for 1.4%.

The claimed technical solution is aimed at creating a highly efficient cost-effective method of extracting scandium from productive solutions and sorbent for this method, which provides increased selectivity for scandium.

Disclosure of invention

The technical result achieved by the use of a new method for extracting scandium from productive solutions using a new impregnated sorbent consists in high processability and cost-effectiveness of the method, reducing raw material costs, high sorption rates for scandium extraction at pH 1.1-1.25 high sorption rates for scandium, increased selectivity and high sorption capacity for scandium, and low sorption values for the main rare earth impurities - iron (III) and aluminum (III).

The specified technical result is achieved in a method for extracting scandium from a productive solution obtained after leaching of scandium-containing raw materials, including sorption of rare-earth metals (REM) on a strongly acidic cation exchange resin with subsequent desorption of REM and the removal of the eluate, sorption of scandium on an styrene-diphenylbrenzoleborgeneblock resin which uses di- (2,4,4-trimethylpentyl) phosphinic acid with the addition of di-2-ethylhexylphosphoric acid, to obtain the solution of the return solution, aimed at leaching and desorption of scandium with the conclusion of the eluate.

As a scandium-containing solution, a productive solution of underground downhole leaching of uranium is used, which is formed after uranium extraction, which does not require pH adjustment for sorption of rare-earth metals and scandium.

For desorption of rare-earth metals from cation exchange resin, a solution of ammonium sulfate with a concentration of 150-300 g / l is used, desorption is carried out in discrete mode with the withdrawal of a commercial fraction of the eluate in an amount of 3-10 specific volumes for 1-3 hours. The use of sulfate salts for the desorption of rare-earth metals from a strongly acidic cation exchanger provides a low residual capacity of cation exchanger by the amount of rare-earth metals, which, in turn, allows the use of a strongly acidic cateonite in a multi-cyclic version.

Quantitative sorption of rare-earth metals on a strongly acidic cation exchanger before sorption of scandium on an impregnated sorbent helps to create more favorable conditions and modes of the main process.

In contrast to the prototype, in which prior to sorption of scandium on TVEX, alkalization of the solution to pH 2.5-3 is required, in the proposed method for sorption of scandium with an unchanged pH range of the product solution equal to 1.1-1.25, a highly selective sorbent is used, representing a porous carrier (matrix) with an extractant-impregnate of a phosphorus-containing series, namely, di- (2,4,4-methylpentyl) phosphinic acid with the addition of di-2-ethylhexylphosphoric acid. This impregnated sorbent has a high selectivity for scandium in return solutions having a working pH range of 1.1-1.25 directed to repeated operations of underground downhole leaching of uranium with the simultaneous transfer of an accompanying valuable component of scandium into a productive solution.

In this case, after desorption of scandium, part of the eluate is sent to obtain scandium, and part for the saturation of the sorbent with scandium.

The specified technical result is achieved by using an impregnated sorbent to extract scandium from product solutions based on a styrene-divinylbenzene carrier with an organophosphorus extractant, which is used as di- (2,4,4-trimethylpentyl) phosphinic acid with the addition of di-2-ethylhexylphosphoric acid, in the following ratio components, mass. %:

di- (2,4,4-trimethylpentyl) phosphinic acid 40-60 di-2-ethylhexylphosphoric acid 3-5 styrene divinylbenzene rest

The specified technical result is achieved by the fact that in the method for producing an impregnated sorbent for the extraction of scandium from productive solutions obtained by suspension copolymerization of styrene and divinylbenzene in the presence of an organophosphorus extractant, di- (2,4,4-trimethylpentyl) phosphinic acid with the addition of di -2-ethylhexylphosphoric acid, in the following ratio of components, mass. %:

di- (2,4,4-trimethylpentyl) phosphinic acid 40-60 di-2-ethylhexylphosphoric acid 3-5 styrene divinylbenzene rest

the resulting mixture is kept for 3-4 hours in deionized water at a temperature of 85-90 ° C and a volume ratio of 1: 1, add a pore former - isooctane in an amount of 15-25 mass. %, incubated for 1-2 hours at the same temperature, then sharply cooled, formed granules are separated on a sieve, granules are vacuum treated at 5-10 mm water. with obtaining porous granules. After vacuum distillation, the granules were screened by fractions.

A specific feature of the preparation of an impregnated sorbent is the formation of a macroporous structure, which is obtained as a result of introducing isooctane into the composition of the components at the stage of pore-forming agent in an amount of 15-25% of the sum of styrene and divinylbenzene monomers and isooctane removed from the system during vacuum distillation to form the desired macroporous structure. The introduction of a blowing agent allows not only to create a porous structure, but also to regulate the pore size and diameter of the microchannels inside the granules of the impregnated sorbent, which depend on the consumption of isooctane; the diameter of the micropore channels ranges from 200 to 2500 nm.

A feature of the method is the comparative ease of synthesis. In addition, the use of a pore former in the synthesis of styrene and divinylbenzene monomers promotes the formation of the porous structure of impregnated sorbent granules, which favorably affects the increase in the diffusion rate of scandium cations in aqueous solutions deep into the sorbent grains and an increase in sorption capacity for scandium.

The high capacity of the scandium impregnated sorbent is ensured by the optimal content of components:

less than 40 mass. % of the extractant is impractical to use due to a decrease in scandium capacity due to insufficient filling of the channels of the impregnated sorbent with the introduced reagent;

more than 60 mass. % of the extractant in the composition of the impregnated sorbent leads to an increase in the degree of leaching of the extractant from the phase of the impregnated sorbent, since in addition to the channels in this case, the extractant does not come into contact with the matrix and therefore is easily lost upon contact with aqueous solutions.

By introducing a blowing agent, the porous structure and the average pore diameter can be controlled; the optimum flow rate is 15-25 mass. % to the sum of monomers. With a decrease in the consumption of isooctane of less than 15%, a large-pore structure with an increased average pore diameter is formed to the sum of monomers. An increase in the flow rate of the blowing agent by more than 25% leads to a finely porous structure. Therefore, the average diameters of the channels and pores can be controlled if the dimensions of the extracted or shared ions are known.

The proposed invention was carried out as follows.

To obtain an impregnated sorbent, its synthesis was carried out. The synthesized material is a macroporous carrier consisting of styrene, divinylbenzene as a crosslinking agent, filled with the extractant di- (2,4,4-trimethylpentyl) phosphinic acid with the addition of di-2-ethylhexylphosphoric acid.

The copolymerization method is suspension. The blowing agent is introduced at the stage of synthesis and quantitatively removed by vacuum distillation.

Characterization of the impregnated sorbent after vacuum distillation of the blowing agent:

granule size - 0.31-1.6 mm;

bulk density - 660 g / l;

granule density - 0.97 g / ml;

total porosity - 19 and 1 t of sorbent;

the average pore diameter is 1200 nm.

Impregnated sorbent granules were investigated for scandium sorption characteristics upon contact with a model solution. This solution was prepared from reagents and simulated the composition of the return productive solution for the following main components, g / l: 1.0 iron (III); 1.5 aluminum (III); 1.0 sodium; 0.5 calcium; 0.1 sum of rare-earth metals of the light group (for example, lanthanum); 20.8 sulfate ion, pH 1.2. The scandium content was 0.056 g / l and was obtained by dissolving the calculated scandium oxide in a model solution at pH 1.2.

It was established empirically on a model solution that the sorption capacity for scandium and mechanical properties depend on the amount of extractants introduced and on the content of a crosslinking agent, divinylbenzene, in the mixture of monomers in the reaction mixture. It was shown that the optimal content of the main extractant in the matrix of styrene-divinylbenzene copolymer, necessary to obtain the maximum scandium impregnated sorbent capacity, is 40-60 mass. %, as well as 3-5 mass. % di-2-ethylhexylphosphoric acid, the rest is styrene divinylbenzene.

It was found that the porous structure of the impregnated sorbent has a significant effect on the kinetic properties of scandium. So, the time to establish equilibrium during sorption of scandium from a model solution on a gel (non-porous) form of an impregnated sorbent was 76 hours, and on a porous analogue - 16 hours.

Comparative studies with the prototype to determine the sorption properties of the impregnated sorbent of the porous structure and TVEKS-DI2EGFK were carried out on a technological solution, which is a return solution after sorption of uranium, selected at one of the underground leaching (PV) enterprises, but reinforced with scandium by dissolving the calculated amount of scandium reactive oxide . Moreover, the concentration of scandium after the reinforcement of the industrial solution should not exceed the actual concentration by more than 50 times. In this case, in accordance with the theory of similarity, it is possible to some extent guarantee the modeling of the technological process.

Comparative experiments were carried out on an industrial solution further fortified with scandium of the following composition, mg / l: 43.2 scandium; 1212 sodium; 138 potassium; 426 calcium; 29.6 REM amounts; 0.5 uranium; 1.64 thorium; 1.23 molybdenum; 16.9 vanadium; 25.6 zinc; 2.3 nickels; 0.91 cobalt; 23.7 manganese; 1670 iron; 1986 aluminum; 78.6 silicon; 3.86 yttrium; 16.8 sulfate ion; pH 1.2, temperature 18-22 ° C. Of the total REM content of 29.6 mg / l, the main content is composed of elements of the light REM group plus samarium, they make up 66% of the total number of REM. The content of each of the elements of the light group, mg / l: 3.0 lanthanum; 7.62 cerium; 1.5 praseodymium; 6.25 neodymium and 1.26 samarium.

The productive solution is first passed through a column with the strongly acidic cation exchanger of the isoporous structure of Lewatit MonoPlus SP112 [H ⁺ ], that is, in the hydrogen form, to take the output curve of the sorption of the sum of rare-earth metals. REM sorption was carried out at an equilibrium pH of 1.2. The results of the experiments showed that the extraction of the amount of rare-earth metals from the solution into the ion exchanger was 99.3% (the content in the discharge was 0.2 mg / l by the sum of the rare-earth metals). The sorption capacity of cation exchanger in the amount of rare-earth metals at full saturation of the column was 64.2 mg / g of sorbent. The number of sorption columns is 3. After saturation of the column with cation exchange resin according to REM and washing the cation exchange resin is subjected to desorption with a solution of ammonium sulfate with a concentration of 250 g / l. The eluate is sent to obtain the total REM concentrate, the residual REM content in the resin after passing 10 specific volumes of desorbent was 0.0108%, which indicates an almost complete removal of REM from cation exchanger. Losses of scandium after sorption of rare-earth metals amounted to 0.65% of the amount received for sorption of rare-earth metals with a productive solution. These data confirm the lyophilic series of REM affinity for strongly acidic cateonite, in which scandium is displaced from the resin phase by REM cations, especially in the case of a significantly higher concentration of REM than sorbed scandium.

A product solution with pH 1.2 after sorption of rare-earth metals entered the columns filled with an impregnated sorbent of a porous structure, in which the extractant of the phosphorus-containing series of di- (2,4,4-trimethylpentyl) phosphinic acid with the addition of di-2-ethylhexylphosphoric acid was used as an impregnate . The purpose of the operation is the quantitative sorption of scandium at a pH of the productive solution of 1.2. The number of columns is 4. The sorption capacity was determined not only by the flow rate of the productive solution with a known concentration of scandium passed through a dense sorbent layer, but also by the results of fluoride desorption of scandium with subsequent weighing of a sample of saturated impregnated sorbent.

After saturation of the sorbent in three of the four sorption apparatuses with a fixed bed of impregnated sorbent, the solution was returned to leach uranium and associated valuable components, and the impregnated sorbent was desorbed with hydrofluoric acid and washed with water, after which it was again ready for repeated sorption scandium cycles.

The implementation of the invention

The following is information confirming the implementation of the proposed inventions, as well as a comparison of the effectiveness of the known and proposed technical solutions, are given in the examples.

Example 1

Synthesis of the proposed impregnated sorbent (impregnate - extractant di- (2,4,4-trimethylpentyl) phosphinic acid.

In a 750-ml glassy carbon beaker, 100 g of styrene-divinylbenzene and di- (2,4,4-trimethylpentyl) phosphinic acid, 5 g of di-2-ethylhexylphosphoric acid were mixed, mixed thoroughly and kept at 85-90 ° С for 3-4 hours, the isooctane pore former was added in an amount of 20% by weight of the monomers, again kept for 1-2 hours at the same temperature, then it was rapidly cooled, granules were separated from the resulting mother liquor on a sieve with a mesh size of 0.5 mm. After separation on a polypropylene mesh, the granules were vacuum treated at a vacuum of 5-10 mm. water Art., while removing water and the pore former isooctane, forming the porous structure of the sorbent. After vacuum distillation, the granules were subjected, if necessary, to sieving in fractions. Characterization of the impregnated sorbent after vacuum distillation of the blowing agent:

granule size - 0.31-1.6 mm (the amount of the working fraction of 0.6-1.6 mm was 87%);

bulk density - 660 g / l;

granule density - 0.97 g / ml;

total porosity - 79 m ² / g of sorbent;

the average pore diameter is 1200 nm.

Example 2

The determination of the main technological indicators of scandium sorption on the proposed impregnated sorbent was carried out in the following way.

Preliminary sorption of the amount of rare-earth metals was carried out on a productive return solution of one of the PV enterprises. The operation of cleaning the productive solution from the amount of rare-earth metals was carried out in column apparatuses with a fixed layer of ion exchanger. The number of sorption apparatuses is 3. The optimal transmission rate of the solution through the ion exchanger layer was 6 beats. about. in hour. The sorbent used was Lewatit MonoPlus SP112 sulfocationionite, supplied in commercial hydrogen form. The content of rare-earth metals in the solution after sorption was maintained at a level of 0.2-0.5 mg / L. The column was considered saturated in rare-earth metals, when the content of rare-earth metals in the solution after sorption approached the content in the initial solution entering the column, after which the column was removed for washing and desorption of rare-earth elements. Alkali metal and alkaline earth metal cations, as well as zinc, nickel, cobalt, iron, aluminum, and other cations present in the productive solution, were sorbed along with rare-earth metals on sulphocationite.

Table 1 shows the results of the sorption of the amount of rare-earth metals on Lewatit MonoPlus SP112 (H ⁺ ) sulfocationite from a productive return solution - the results of laboratory experiments. The composition of the initial solution, mg / l: 0.73 Sc; 29.6 REM; 1235 Fe; 1390 Al; pH 1.22. The sorption rate of 6 beats per hour, room temperature.

From the data obtained in table 1 it follows that REM cations easily displace scandium from the resin during the passage of the productive solution at pH 1.22. In this pH range, the sorption of impurities of rare earth metals is negligible.

To compare the sorption indicators for scandium for the impregnated sorbent according to the claimed invention and the prototype, studies were made of the dynamics of sorption on two scandium absorbers. As a solution for conducting comparative experiments, we used a productive solution obtained after sorption of rare-earth metals on an impregnated sorbent, of the following composition, mg / l: 43.2 scandium; 0.5 amount of rare-earth metals; 1430 iron (III); 1790 aluminum (III); 16800 sulfate ion; pH 1.2. Sorbents were compared: impregnated sorbent according to the claimed method and TVEKS-DI2EGFK. Each absorber was loaded into columns with the same geometric dimensions (the ratio of the layer height to the column diameter is 10). Grain sorbents 0.3-1.6 mm in both compared cases. The sorption process was carried out under the same conditions of solution flow and temperature.

Table 2 shows the comparative sorption characteristics of the sorbents for scandium and the main non-earth impurities of iron and aluminum of the prototype (TVEKS-DI2EGFK) and the proposed method (impregnated sorbent) during sorption in the dynamics of dense layers from a productive industrial solution that has passed the stage of preliminary sorption of the amount of rare-earth metals on sulfosol. The flow of the solution through the resin layers is 6 beats. about. in hour. Temperature 19 ° C. The ratio of the layer length to the diameter in each battery of columns is 12.

From the data of table 2 it follows that the difference in the extraction of scandium (average data for the saturation of each column in the battery) for the resin from the productive solution, which passed the stage of purification from the amount of rare-earth metals on sulfosol, is very significant: 98.8% by the proposed method and 34.6 % of the prototype. At the same time, sorption capacities according to scandium also vary significantly, as well as lengths of discharge sorption curves for scandium. The behavior of the impurities of the main non-earth metals is such that TVEKS-DI2EGFK absorbs impurities to a greater extent than the proposed impregnated sorbent.

Example 3

Comparative characteristics of the purity of the products after desorption.

Sorbents were saturated in static under the same conditions - the concentration of scandium in the productive solution, the ratio of the volumes of the solution and the sorbent, temperature, mixing speed. Methodically, the process was carried out as follows. A sorbent saturated with scandium was subjected to desorption with a solution of hydrofluoric acid with a concentration of 2.5 mol / L. The process of desorption of scandium was carried out in dynamics in a discrete mode with a speed of 2-4 beats. per hour, that is, at first pore liquid was withdrawn, which practically did not contain fluorine ion, with a volume of 0.4-0.5 beats. vol., then a commodity fraction, the volume of which was 1.5-4.5 beats. solution and in which 75-90% of scandium was concentrated from the amount contained in the resin before the start of the desorption process. The “tail” fraction was sent to prepare desorbent. The commercial fraction was sent to obtain a compound of scandium, in particular to obtain fluoride. The resin was washed from the stripping solution and was again used to carry out a sorption process to extract scandium.

As objects of comparison of the proposed method and the prototype, the final solutions of scandium were selected, which are sent to obtain compounds of scandium, for example, scandium fluoride. To do this, experiments were conducted on the same productive solutions according to the prototype and the proposed method. The final solutions were as follows. According to the prototype, a reextract after reextraction of TVKS, which is a matrix based on styrene and divinylbenzene with an organophosphorus compound, phosphoric acid di-2-ethylhexyl ether (DI2EGFK), and a solution of hydrofluoric acid at room temperature. According to the proposed method, the eluate after desorption of scandium from an impregnated sorbent (IS), which was used as a porous styrene-divinylbenzene carrier extractant di- (2,4,4-trimethylpentyl) phosphinic acid, a solution of hydrofluoric acid according to the parameters of the prototype.

Table 3 shows comparative data of the chemical compositions of the reextract according to the prototype and the eluate of the proposed method, aimed at obtaining a commercial compound of scandium.

As follows from the data of table 3, the method of extracting scandium from a productive solution according to the proposed method provides a deeper purification of the final solution of scandium, directed to obtain a commodity compound, in comparison with the prototype.

Thus, the proposed solutions increase the economic efficiency of industrial technology for processing productive solutions of underground downhole leaching of uranium due to the high selectivity of the proposed sorbent for the extraction of scandium in the pH range of the return solution, which can significantly reduce the consumption of reagents, and also improve the quality of the final products of scandium.

Claims (5)

1. A method of extracting scandium from productive solutions obtained after leaching of scandium-containing raw materials, comprising sorption of scandium on an impregnated sorbent based on a porous styrene-divinylbenzene carrier with an impregnated organophosphorus extractant to obtain a return solution for leaching, and the removal of scandium preliminary from the productive solutions before sorption of scandium, rare-earth metals are sorbed on a strongly acidic cation those porous structure with subsequent desorption of rare earth metals and eluate withdrawal, and as the organophosphorus extractant is used in sorption scandium di- (2,4,4-trimethylpentyl) phosphinic acid with the addition of di-2-etilgeksilfosfornoj acid. 2. The method according to p. 1, characterized in that the desorption of rare-earth metals from cation exchange resin is carried out in discrete mode for 1-3 hours with a solution of ammonium sulfate concentration of 150-300 g / l with the conclusion of the eluate in the amount of 3-10 specific volumes. 3. The method according to p. 1, characterized in that the sorption of scandium is carried out on an impregnated sorbent containing these components, in the following ratio, wt. %: di- (2,4,4-trimethylpentyl) phosphinic acid 40-60 di-2-ethylhexylphosphoric acid 3-5 styrene divinylbenzene rest 4. The method according to p. 3, characterized in that the pore size of the styrene-divinylbenzene carrier is 200-2500 nm.