Method for extractng target component from feed solution by sorption

Abstract

The proposed invention relates to a method for extracting a target component from a feed solution by sorption in a top-down direction, applicable, inter alia, to natural brines and waters, process solutions and wastewater from various industries. What is proposed is a method for extracting a target component from a feed solution by sorption which includes: a) a top-down sorption step in which a feed solution is passed through a sorbent to extract a target component, b) a sorbent washing step, c) a desorption step, and d) a displacement step. The liquid fed to step d) has a density in a range of 0.9-1.3 of the density of the feed solution in step a). The liquid fed to step d) is passed through the sorbent in a bottom-up direction. The technical result of the invention is a high extraction of target component from a feed solution during top-down sorption performed at high speeds (more than 8-10 m / h), such as those used in large-scale industrial columns, in addition to an increase in the effective working life of the sorbent (an increase in the service life of the sorbent).

Description

[0001] METHOD OF SORPTION EXTRACTION OF THE TARGET COMPONENT FROM THE INITIAL SOLUTION

[0002] Field of technology

[0003] The proposed invention relates to a method for the sorption extraction of a target component from a source solution in a top-down direction, including from natural brines and waters, process solutions and wastewater from various industries.

[0004] Prior art

[0005] Patent RU2816073, published on March 26, 2024, discloses a method for the sorption production of lithium concentrate from a lithium-containing solution, which comprises: an sorption step, including passing the lithium-containing solution through a sorbent to extract lithium, a step for washing said sorbent, and a desorption step. During the sorbent washing step, a washing liquid containing a depleted raffinate and / or a depleted eluate is used for washing. The depleted raffinate is a solution collected from the first 0.4-1.5 column volumes of the solution obtained in the sorption step as a result of contact between the lithium-containing brine and said sorbent. The depleted eluate is a solution taken from any of the 4th, 5th, 6th, 7th or 8th column volumes of the solution obtained at the desorption stage as a result of contact of the desorbing solution with the specified sorbent.

[0006] The disadvantage of the above invention is the insufficiently high extraction of lithium, as well as low efficiency when performing sorption both “bottom-up” and “top-down”, at high speeds (more than 8-10 m / hour), which are used in large-sized industrial columns.

[0007] When performing sorption on a laboratory or industrial scale, the "light on top, heavy on bottom" rule is generally followed. This means that solutions with a higher density than the solution in the column before being fed should be fed into the sorption column from the bottom up. Conversely, solutions with a lower density than the solution in the column before being fed should be fed into the sorption column from the top down. In practice, this is implemented as a countercurrent system, with dense solutions from which extraction occurs fed from the bottom, and light solutions for washing and desorption fed from the top.

[0008] The rationale for this rule is the fact that when solutions are fed contrary to this rule, the solutions begin to move in the column (and sorbent) under the influence of the difference in densities within a narrow channel that does not affect the main part of the sorbent at a speed exceeding the calculated feed rate - a solution flow is formed that flows down the narrow channel along the wall of the column, bypassing the main part of the sorbent on one side.

[0009] Due to the high speed of movement within the channel, the contact time of the solution with the sorbent is many times lower than that required to extract the target component, which leads to breakthrough at the column outlet almost immediately.

[0010] When operating on columns of small height or at low specific loads, this principle works well and allows for efficient extraction of the target component in a fixed sorbent bed. However, as the column height, cascade length, and specific load increase, the linear flow velocity in the column increases. Upon reaching a certain critical linear velocity, the sorbent bed begins to expand and liquefy. This disrupts the uniform flow of the solution in the column, reducing extraction efficiency.

[0011] Thus, increasing the productivity of the sorption unit has some limitations.

[0012] To overcome this limitation, various methods are used to compress the sorbent layer. These include increasing the solution feed rate to compress the sorbent toward the upper filter element, or mechanical compression using various devices.

[0013] However, it is not always possible to use these methods.

[0014] At the same time, when solutions are fed from above, liquefaction of the sorbent cannot occur in principle, but then the problem of the above-described "channeling" of the flow under the influence of the density difference arises, when the flow "bypasses" the main mass of the sorbent on one side. The sorption mode is described by such parameters as flow direction, specific load and linear flow velocity. The linear flow velocity can be determined from the height of the sorbent layer and the specific load according to the equation: v = nh YH where v is the linear flow velocity (m / h), n is the number of columns in the sorption cascade, h is the height of the sorbent layer in an individual column (m), YH is the specific load (h 1(or KO / h). While maintaining the optimal specific load of approximately 1.5-2 KO / h and increasing the volume of columns or the number of columns in the cascade, the total height of the sorbent layer increases and, as a result, the linear flow rate in the column increases.

[0015] Starting from a certain value of the linear velocity, which is determined by the rate of removal of the lightest granules of the sorbent and its porosity (the more densely the sorbent is packed, the higher the flow rate inside the sorbent layer), the sorbent layer expands and liquefies.

[0016] Once the sorbent layer reaches the boundary of the upper filter element and the linear velocity continues to increase, a portion of the sorbent is pressed against the filter element, forming a stationary sorbent layer. When the heaviest sorbent granules reach the entrainment velocity, the sorbent is completely compressed against the upper filter element.

[0017] Due to the liquefaction of the sorbent layer, it is mixed in the column, which disrupts the layer-by-layer saturation of the sorbent and the uniform movement of the sorption front, which leads to a decrease in the degree of extraction, as shown in Fig. 1.

[0018] Thus, effective sorption extraction is possible only at speeds below the onset of sorbent expansion and at speeds higher than the rate of formation of the compressed layer, and at intermediate speeds the extraction is not optimal.

[0019] In addition to reducing the completeness of extraction, working in a fluidized bed leads to an increase in the rate of wear of the sorbent due to mutual friction of the granules or against the column elements.

[0020] When performing countercurrent sorption and desorption (e.g., sorption from below, desorption from above), increased sorbent wear can be observed even when operating in a compressed bed due to periodic sorbent repositioning when the flow direction changes. To reduce sorbent wear and mitigate the effects of fluidization and repositioning, a logical solution is to perform sorption and desorption in a top-down direction. However, experience has shown that performing sorption in this mode from high-density solutions leads to a sharp decrease in recovery.

[0021] Disclosure of invention

[0022] In this application: raffinate is a solution formed in the sorption stage as a result of contact between a lithium-containing solution and a sorbent for lithium extraction; eluate is a solution formed in the desorption stage as a result of contact between a desorbing solution and a sorbent for lithium extraction; column volume (VC) is a volume of liquid equal to the volume of the sorbent involved in the process stage / operation; feed solution is a solution from which the target component is extracted by sorption (e.g., a lithium-containing solution, a copper-containing solution, etc.); target component is the main component that is extracted from the feed solution by sorption (e.g., lithium, copper, etc.), desorption stage is a stage in which the absorbed substance is at least partially removed (withdrawn together with the liquid) from the sorbent, displacement stage is a stage in which the liquid contained in the pores of the sorbent is at least partially replaced by another (displacing) liquid.

[0023] The objective and technical result of the present invention is a high extraction of the target component from the initial solution when performing sorption from top to bottom at high speeds (more than 8-10 m / hour), which are used in large-sized industrial columns, as well as an increase in the effective operating life of the sorbent (an increase in the service life of the sorbent).

[0024] In order to solve the stated problem and achieve the technical result, a method for the sorption extraction of a target component from a source solution is proposed, comprising: a) a sorption stage in the top-down direction, including passing the source solution through a sorbent to extract the target component, b) a stage of washing the said sorbent, c) a desorption stage, d) a displacement stage, characterized in that a liquid having a density in the range of 0.9-1.3 of the density of the source solution in stage a is fed to stage d), while the liquid fed to stage d) is passed through the sorbent in the bottom-up direction.

[0025] At the displacement stage, passing a liquid with a density close to the density of the initial solution used at the sorption stage through the sorbent in the bottom-up direction allows one to avoid liquefaction of the sorbent, as well as to avoid the problem of flow “channeling” under the influence of the density difference, when the flow “bypasses” the main mass of the sorbent on one side, which allows for a high extraction of the target component from the initial solution when performing sorption from the top-down at high speeds (more than 8-10 m / hour), which are used in large industrial columns, as well as an increase in the effective service life of the sorbent (an increase in the service life of the sorbent).

[0026] The sorbent for extracting the target component from the initial solution may be any sorbent known from the prior art that allows for the extraction of the target component.

[0027] For example, lithium-alumina intercalate obtained from hydrated aluminum oxide, layered double hydroxide of lithium aluminum chloride, layered activated aluminum oxide modified with double hydroxide, layered double hydroxide impregnated in an ion-exchange resin or copolymer, or a molecular sieve, or zeolite, or layered aluminate polymer can be used for the extraction (sorption) of lithium. It is more preferable to use a granulated sorbent based on a chlorine-containing variety of aluminum and lithium double hydroxide ([NA12(OH)6]Cl-3H2O), which has recently found wide industrial application.

[0028] For example, the Dowex M4195 sorbent can be used to extract copper, the AXIONITE Pd-sorb and AXIONITE Pd-sorb(s) sorbents can be used to extract palladium from isotopic solutions of silver refining and hydrochloric acid solutions, a strongly basic anion exchanger can be used to extract gold and platinum from chloride solutions, and so on.

[0029] The list of sorbents and elements is not limited to the above. The above sorbents and elements are included because they allow for a visual demonstration of the invention's ability to change sorbent color during sorption.

[0030] In a preferred embodiment, the liquid fed to step d) is passed through the sorbent until the liquid leaving step d) has a density of at least 0.7, preferably at least 0.8, more preferably at least 0.9, of the density of the liquid fed to step d).

[0031] Obtaining the specified density from the liquid displacement stage indicates that most of the liquid contained in the sorbent pores has been displaced and replaced by the liquid fed to the displacement stage, which has a density close to that of the feed solution fed to the sorption stage. This allows for higher recovery of the target component from the feed solution during top-down sorption at high flow rates (over 8-10 m / hour), which are used in large industrial columns, as well as further extending the effective service life of the sorbent.

[0032] In a preferred embodiment, a liquid having a density in the range of 0.9-1.2, preferably 0.9-1.1, of the density of the initial solution in step a) is fed to step d).

[0033] Bringing the density of the liquid supplied to the displacement stage closer to the density of the initial solution allows for a higher extraction of the target component from the initial solution when performing top-down sorption at high speeds (more than 8-10 m / hour), which are used in large-sized industrial columns, as well as an additional increase in the effective operating life of the sorbent (increased service life of the sorbent).

[0034] In a preferred embodiment, in step d), liquid is passed through the sorbent in a volume of at least 1 column volume, preferably in a volume of 1.5 column volumes, more preferably in a volume of 1.2-1.4 column volumes.

[0035] This allows for a higher extraction of the target component from the initial solution when performing top-down sorption at high speeds (more than 8-10 m / hour), which are used in large-sized industrial columns, as well as an additional increase in the effective operating life of the sorbent (increased service life of the sorbent).

[0036] In a preferred embodiment, in step d), liquid is passed through the sorbent at a rate of at least 8 m / h, preferably at least 10 m / h.

[0037] This allows for a higher extraction of the target component from the initial solution when performing top-down sorption at high speeds (more than 8-10 m / hour), which are used in large-sized industrial columns, as well as an additional increase in the effective operating life of the sorbent (increased service life of the sorbent).

[0038] In a preferred embodiment, step d) is supplied with a liquid having a relative content of the target component of less than 10%, preferably less than 5%, more preferably less than 2%, of the concentration of the target component in the initial solution in step a).

[0039] Concentrations can be expressed in any form (mass %, mol / L, g / L), the main thing is that the concentration in the displacement solution is less than 10%, preferably less than 5%, more preferably less than 2%, of the concentration of the target component in the initial solution at stage a). This ensures a higher extraction of the target component from the initial solution during top-down sorption at high speeds (more than 8-10 m / hour), which are used in large industrial columns, as well as an additional increase in the effective service life of the sorbent (an increase in the service life of the sorbent).

[0040] In a preferred embodiment, at step c), liquid is passed through the sorbent in a top-down direction.

[0041] At step c), the liquid can be passed through the sorbent in any direction, however, the different directions of liquid flows at the desorption step (top-down) and the displacement step (bottom-up) increase the degree of liquid displacement from the sorbent pores, which ensures a higher extraction of the target component from the initial solution when performing top-down sorption at high speeds (more than 8-10 m / hour), which are used in large industrial columns, as well as an additional increase in the effective operating life of the sorbent (an increase in the service life of the sorbent). The liquid used at the desorption step can be any liquid known from the prior art that is used for the desorption of the corresponding sorbent: for a sorbent for lithium extraction - water, for a sorbent for copper extraction - an ammonia solution having a concentration in the range of 5-10% and a density in the range of 0.9-0.95, etc.

[0042] As a rule, if desorption is not carried out with water, then after desorption the sorbent is washed with water before the displacement stage.

[0043] In a first particular embodiment, the source solution is a lithium-containing solution and the target component is lithium.

[0044] Preferably, in the first particular embodiment, a liquid containing at least one of the following is fed to stage d): raffinate obtained in the sorption stage, sodium chloride solution.

[0045] The above-mentioned liquids contain salt solutions, which are the main component of the sorption solutions used and are chemically compatible with the solution being processed. This means that when mixed with such a solution, no chemical reactions occur, no precipitates form, and no salting out of individual components is observed. This allows for higher recovery of the target component from the feed solution during top-down sorption at high speeds (over 8-10 m / hour), which are used in large industrial columns, as well as an additional increase in the effective service life of the sorbent.

[0046] The raffinate obtained in the known method at the sorption stage (stage a)) can be conditionally divided into two fractions:

[0047] 1) at the very beginning of sorption (the first 0.5-1.5 KO) a fraction with a low salt content and a density close to 1 (depleted raffinate) emerges,

[0048] 2) the raffinate collected after the first 1.5 KO has a high salt content and a density close to the density of the original solution.

[0049] In the prototype, the raffinate from the first fraction (depleted raffinate) with a low salt content is used to wash the sorbent.

[0050] In the present invention, at the very beginning, the raffinate from the second fraction is used for displacement, which has approximately the same density, close to the density of the original solution, such raffinate is suitable for use in the displacement stage, but it cannot be used for washing.

[0051] When continuing the cycle after introducing the displacement stage before sorption, fractionation of the raffinate at the sorption stage may not be carried out, since at the beginning of the sorption stage, a displacement solution containing a lot of salts will leave the column.

[0052] In a second particular embodiment, the feed solution is a copper-containing solution and the target component is copper.

[0053] Preferably, in the second particular embodiment, a liquid containing at least one of the following is fed to stage d): raffinate obtained in the sorption stage, silver nitrate solution.

[0054] The above-mentioned liquids contain salt solutions, which are the main component of the sorption solutions used and are chemically compatible with the solution being processed. This means that when mixed with such a solution, no chemical reactions occur, no precipitates form, and no salting out of individual components is observed. This allows for higher recovery of the target component from the feed solution during top-down sorption at high speeds (over 8-10 m / hour), which are used in large industrial columns, as well as an additional increase in the effective service life of the sorbent.

[0055] The raffinate obtained in the known method at the sorption stage (stage a)) can be conditionally divided into two fractions:

[0056] 1) at the very beginning of sorption (the first 0.5-1.5 KO) a fraction with a low salt content and a density close to 1 (depleted raffinate) emerges,

[0057] 2) the raffinate collected after the first 1.5 KO has a high salt content and a density close to the density of the original solution.

[0058] In the prototype, the raffinate from the first fraction (depleted raffinate) with a low salt content is used to wash the sorbent.

[0059] In the present invention, the raffinate from the second fraction is used for displacement at the very beginning. This raffinate has a roughly uniform density, close to that of the feed solution. This raffinate is suitable for use in the displacement stage, but cannot be used for washing. If the cycle is continued after the displacement stage is introduced before sorption, fractionation of the raffinate in the sorption stage may be omitted, since at the beginning of the sorption stage, the column will exit with a displacement solution containing high levels of salts.

[0060] In a preferred embodiment, at least part of the liquid leaving in the first 0.5-1 column volumes from step d) is used to wash the sorbent in step b).

[0061] The liquid leaving in the first 0.5-1 KO from stage d), i.e. the displacement solution, has a low salt content and a density close to 1. The use of the above liquid for washing the sorbent allows for a higher extraction of the target component from the initial solution when performing top-down sorption at high speeds (more than 8-10 m / hour), which are used in large industrial columns, as well as an additional increase in the effective operating life of the sorbent (an increase in the service life of the sorbent).

[0062] Brief description of the drawings

[0063] The drawings are presented for a better understanding of the invention, however, it will be obvious to a person skilled in the art that the disclosed invention is not limited to the embodiment shown in them.

[0064] Fig. 1 schematically shows the state of the sorbent in the column in an ascending flow with an increase in the linear flow velocity.

[0065] Fig. 2 shows a graph of the change in the height of the sorbent layer in the expanded and compressed state at different linear flow rates according to example 2.

[0066] Fig. 3 shows graphs of lithium sorption from a lithium-containing solution with a density of about 1.2 g / ml by a known method when feeding the lithium-containing solution from the bottom up and from the top down: according to example 1 (feeding from the bottom up) and according to example 3 (feeding from the top down).

[0067] Fig. 4 shows graphs of lithium sorption from a lithium-containing solution when fed from top to bottom after displacing the eluate from the sorbent with the fed NaCl solution (experiment 1) and raffinate (experiment 2), as well as when feeding the lithium-containing solution from bottom to top in a known manner.

[0068] Fig. 5 shows a schematic of the movement of solutions and the copper sorption front in the sorption column according to examples 6, 7 and 8. Embodiments of the invention. The best embodiment of the invention

[0069] The described embodiments are provided for illustrative purposes only. Those skilled in the art will readily recognize that other embodiments are possible without changing the essence of the invention.

[0070] To eliminate the influence of the difference in density when feeding a dense sorption solution from above, before the start of sorption, the eluate is displaced from the column using a solution with a density close to the density of the sorption solution, but not containing the extracted component or containing it in low concentrations.

[0071] The displacement is carried out in the direction from bottom to top.

[0072] Example 1 (known method). Sorption in the bottom-up direction (prototype)

[0073] Lithium sorption was carried out from a solution of LiCl (2.5 g / l for chloride, 400 mg / l for lithium) and NaCl (250 g / l) with a density of 1.18 g / cm 3 Using a 24mm internal diameter sorption column filled with 50 ml of Li-sorb(3) sorbent (the sorbent was pre-treated for sorption) (the sorbent bed height in the column was 110 mm). The column was 80% filled with sorbent, leaving a free volume of approximately 18 ml above the sorbent bed.

[0074] The solution was fed using a peristaltic pump at a rate of 75 ml / h (specific load 1.5 KO / h, linear flow velocity 0.165 m / h) through a nozzle at the bottom of the column. The raffinate exited the column through a nozzle at the top and was collected into separate fractions using a fraction collector for subsequent analysis. Figure 3 shows a graph of the lithium content at the outlet of the sorption column.

[0075] Example 2 (known method). Observation of the effect of liquefaction and mixing of the sorbent layer with increasing linear flow velocity.

[0076] In the example described above, due to the small volume of the column, the linear flow velocity is several orders of magnitude lower than in large-volume industrial columns.

[0077] Observing the sorbent liquefaction effect on a laboratory scale is only possible with a significant increase in the specific load. Furthermore, sorption extraction is obviously ineffective due to the significant reduction in brine residence time in the column. Therefore, raffinate collection and analysis were not performed during the liquefaction process simulation. Table 1 and Fig. 2 present data on the dependence of bed heights of fixed, liquefied, and compressed sorbents on volumetric flow rate and linear flow velocity. Pump capacity was calculated based on target linear velocity values, and the sorbent bed height was determined using a scale with a 5 mm division value.

[0078] Table 1. Recorded height of the sorbent layer in the expanded and compressed state at different flow rates.

[0079] Example 3 (known method). Sorption in the top-down direction.

[0080] Example 3 differs from example 1 by a change in the direction of solution feed. The solution was fed to the top of the column, and the raffinate was collected from the bottom of the column and fractionated.

[0081] Fig. 3 shows a graph of the lithium concentration at the outlet of the sorption column obtained according to Example 3 in comparison with Example 1.

[0082] As can be seen from the graphs provided, when fed from above, lithium breakthrough is observed almost immediately after the start of sorption, while lithium extraction does not exceed 75%.

[0083] Example 4 (according to the invention). Differs from example 3 in that before sorption, a NaCl solution with a density equal to the density of the sorption solution (sodium chloride content 250 g / l, density 1.18 g / cm) was fed into the column with the sorbent. 3 ).

[0084] Sodium chloride solution was administered in a quantity of 50 ml over 20 minutes.

[0085] The solution exiting the top of the column was fractionated and analyzed, with each fraction collected over a 4-minute period. After filling the column with sodium chloride solution, adsorption was performed as in Example 3.

[0086] Table 2 shows the results of the analysis of the fractions exiting when the column is filled with a sodium chloride solution, and Fig. 4 shows a graph of the lithium concentration at the outlet of the sorption column during sorption according to Example 4 (Feed from the top, exp. 1) and Example 5 (Feed from the top, exp. 1) in comparison with Example 1 (Feed from the bottom).

[0087] Table 2. Composition of fractions that are displaced from the column by feeding NaCl solution into it.

[0088] As can be seen from the graphs, the curve shapes are virtually identical. The only significant difference is that the first fraction of the raffinate from Example 4 contains significantly less lithium, which can be explained by the removal of free lithium from the column when it is filled with sodium chloride solution (fractions 1-3 in Table 2).

[0089] From Table 2 it can be seen that the first fractions displaced from the sorbent (x01, x02, x03) of the eluate in the volume of the first 0.6 KO have a high lithium content and low density, and the last fractions (x04, x05) have a low lithium content and high density.

[0090] In each subsequent fraction, the density increases due to the fact that the supplied liquid displaces the eluate from the pores of the sorbent; as the eluate is removed from the pores of the sorbent, a solution begins to emerge from the sorption-desorption column, containing an ever smaller amount of eluate (having a low density) and an ever larger amount of displacement solution (liquid) (having a high density).

[0091] The eluate is displaced until the density of the fraction exiting the column reaches a value close to the density of the lithium-containing solution that will be fed for sorption. Example 5 (according to the invention). Differs from Example 4 in that the sodium chloride solution obtained at the beginning of lithium sorption according to Example 4, having a density of 1.18 g / cm, was used instead of the sodium chloride solution. 3 , equal to the density of the initial solution supplied for sorption.

[0092] To fill the column, an increased volume of solution (60 ml) was used, and during fractionation, the collection time of the first fraction was 12 minutes.

[0093] Table 3 shows the results of the analysis of the fractions exiting when the column is filled with the raffinate solution, and Fig. 4 shows a graph of the lithium concentration at the outlet of the sorption column during sorption according to Example 4 (Feed from the top, exp. 1) and Example 5 (Feed from the top, exp. 1) in comparison with Example 1 (Feed from the bottom).

[0094] Table 3. Composition of fractions that are displaced from the column by feeding raffinate into it.

[0095] From Table 3, it is clear that the first fractions (x01) of the eluate displaced from the sorbent in the volume of the first 0.6 KO have a high lithium content and low density, and the last fractions (x02, x03, x04) have a low lithium content and high density.

[0096] In each subsequent fraction, the density increases due to the fact that the supplied liquid displaces the eluate from the pores of the sorbent; as the eluate is removed from the pores of the sorbent, a solution begins to emerge from the sorption-desorption column, containing an ever smaller amount of eluate (having a low density) and an ever larger amount of displacement solution (liquid) (having a high density).

[0097] The displacement of the eluate is carried out until the density of the fraction leaving the column reaches a value close to the density of the lithium-containing solution that will be fed for sorption.

[0098] Fig. 4 shows graphs of lithium sorption with top-down feeding after displacement of the eluate from the sorbent by raffinate fed from the bottom-up. As can be seen from the tables, displacement of the eluate by the raffinate allows for the separation of a relatively pure fraction of 0.6 KO, which can be returned to the process cycle (e.g., for column washing, as in the prior art method).

[0099] In this case, as can be seen in Fig. 4, subsequent sorption proceeds practically identically, regardless of the direction of supply of the sorption solution, which differs greatly from the results without preliminary displacement of the eluate by the raffinate, shown in Fig. 3.

[0100] As can be seen from the graphs in Fig. 4, the sorption curves for examples 1, 4 and 5 are practically identical, which confirms the possibility of effective sorption in the top-down direction under the condition of pre-filling the column with a sodium chloride solution with a density close to the sorption solution or raffinate from the previous sorption cycle.

[0101] When filling the column with raffinate, a solution with a low salt content was collected from the column outlet, which can be used to wash the sorbent in accordance with the prototype patent, and due to this, water consumption was reduced.

[0102] To test the hypothesis about the accelerated movement of a dense solution under the influence of gravity and to visualize the movement of the sorption front, experiments were conducted simulating the sorption of copper from a silver refining electrolyte.

[0103] Example 6 (known method). Copper sorption was carried out using the Dowex M4195 sorbent from a solution of silver nitrate (AgNOs content 300 g / l) and copper nitrate (Cu(I)3)2 content 30 g / l) with a density of 1.2 g / cm 3 The volume of the sorbent in the column was 50 ml, the solution feed rate was 50 ml / h. Before copper sorption, the sorbent was brought to working condition using a 5% nitric acid solution (density 1.03 g / cm 3 )

[0104] When a blue-green solution was fed through the sorbent from the bottom up, the sorbent's color changed from pale yellow to blue-green due to the sorption of copper ions, and the incoming solution became discolored. When the solution was fed into the column for a long time, a slow and steady movement of the colored front from the bottom up was observed.

[0105] Since the goal of the experiment was to visually observe the sorption front, to reduce consumption of the silver-containing solution, sorption was carried out until the sorbent was partially colored (approximately 30% of the sorbent layer height), i.e., clearly before reaching copper breakthrough. Therefore, the solution from the column outlet was not analyzed.

[0106] Example 7 (known method). Differs from example 6 in the direction of nitrate solution feed. When feeding the copper-containing solution from top to bottom, a blue coloration of the solution above the sorbent was observed, and the copper-containing solution rapidly moved through a narrow channel within the sorbent layer along the wall of the sorption column, with a corresponding coloration of the sorbent. After the colored channel reached the lower boundary of the sorbent layer, the solution at the column outlet became colored with a gradual increase in color intensity.

[0107] Example 8 (according to the invention). Differs from example 7 in that before sorption, the column with the sorbent was filled with a solution of silver nitrate (300 g / l, density 1.2 g / cm 3 , equal to the density of the initial solution supplied for sorption). Upon subsequent supply of a copper-containing solution, the solution above the sorbent layer became colored, followed by uniform movement of the colored sorption front.

[0108] Fig. 5 shows a schematic of the movement of solutions and the copper sorption front in the sorption column according to examples 6, 7 and 8.

[0109] Thus, the claimed invention provided:

[0110] - high extraction of the target component from the initial solution when performing sorption from top to bottom at high speeds (more than 8-10 m / hour), which are used in large-sized industrial columns,

[0111] - increasing the effective operating life of the sorbent (increasing the service life of the sorbent), since there was no liquefaction and mixing of the sorbent layer when the linear flow velocity increased.

Claims

Invention formula 1. A method for the sorption extraction of a target component from a source solution, comprising: a) a sorption stage in a top-down direction, including passing the source solution through a sorbent to extract the target component, b) a stage of washing said sorbent, c) a desorption stage, d) a displacement stage, characterized in that a liquid having a density in the range of 0.9-1.3 of the density of the source solution in stage a) is fed to stage d), while the liquid fed to stage d) is passed through the sorbent in a bottom-up direction.

2. The method according to item 1, characterized in that the liquid fed to step d) is passed through the sorbent until the liquid leaving step d) has a density of at least 0.7, preferably at least 0.8, more preferably at least 0.9, of the density of the liquid fed to step d).

3. The method according to item 1, characterized in that a liquid having a density in the range of 0.9-1.2, preferably 0.9-1.1, of the density of the initial solution in step a) is supplied to step d).

4. The method according to claim 1, characterized in that at step d) liquid is passed through the sorbent in a volume of at least 1 column volume, preferably in a volume of 1.5 column volumes, more preferably in a volume of 1.2-1.4 column volumes.

5. The method according to item 1, characterized in that at stage d) liquid is passed through the sorbent at a speed of at least 8 m / h, preferably at least 10 m / h.

6. The method according to item 1, characterized in that a liquid with a relative content of the target component of less than 10%, preferably less than, is supplied to stage d). 5%, more preferably less than 2%, of the concentration of the target component in the initial solution in step a).

7. The method according to claim 1, characterized in that at stage c) liquid is passed through the sorbent in a top-down direction.

8. The method according to claim 1, characterized in that the initial solution is a lithium-containing solution, and the target component is lithium.

9. The method according to item 8, characterized in that a liquid containing at least one of the following is fed to stage d): raffinate obtained in the sorption stage, a sodium chloride solution.

10. The method according to claim 1, characterized in that the initial solution is a copper-containing solution, and the target component is copper.

11. The method according to item 10, characterized in that a liquid containing at least one of the following is fed to stage d): raffinate obtained in the sorption stage, a silver nitrate solution.

12. The method according to item 1, characterized in that at least part of the liquid leaving in the first 0.5-1 column volumes from step d) is used to wash the sorbent in step b).

Images