A method for separating and extracting scandium by a combined adsorption and extraction technique

Abstract

The application relates to the technical field of hydrometallurgy, in particular to a method for extracting scandium from a scandium-containing solution containing iron ions by combined extraction and adsorption separation, which comprises the following steps: using a reducing agent to perform a reduction reaction on the scandium-containing solution to obtain a pretreated solution; using a phosphorus-containing impregnated resin to perform first resin adsorption on the pretreated solution to obtain first adsorption resin and a scandium-removed slurry; wherein the phosphorus-containing impregnated resin comprises an acidic cation adsorption resin and a phosphorus-containing extractant; using a chelating resin containing an amino carboxyl group to perform second resin adsorption on the scandium-removed slurry to obtain second adsorption resin; respectively performing impurity removal treatment and desorption on the first adsorption resin and the second adsorption resin to obtain a scandium-rich eluate; and performing purification treatment on the scandium-rich eluate to obtain a scandium product. The method can maximize the recovery of scandium in the scandium-containing solution by reducing the scandium-containing solution with a reducing agent and then using the phosphorus-containing impregnated resin and the chelating resin in series to adsorb the scandium in the scandium-containing solution.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrometallurgy, and particularly relates to a method for extracting and separating scandium by combined extraction and adsorption. BACKGROUND

[0002] Scandium (Sc) is an important metal element, and its demand is increasing year by year. However, the metallurgical process of its purification and recovery is relatively complex, and an effective separation technology is needed. In the current purification method, ion exchange refers to the reversible chemical reaction between liquid-phase ions and solid-phase ions. In the case that some ions in the liquid phase are preferentially adsorbed by the ion exchange solid, in order to maintain the electrical neutrality of the aqueous solution, the ion exchange solid must release equivalent ions back into the solution. Based on the strong chemical activity of Sc, Sc can be separated from other elements by using strong acid cation exchange resin. However, when the ion exchange solid is washed with sulfuric acid in the subsequent process, Sc may form a sulfate complex anion with sulfuric acid. However, the ion exchange resin generally uses volatile organic solvents, which can cause impurities to be mixed in the process of extracting Sc. Based on this shortcoming, ion liquids (ILs) can be used to replace traditional volatile organic solvents. ILs are solvents composed entirely of ions, and have been studied as non-volatile alternatives to organic solvents. However, ion exchange resins containing ILs are easily oxidized and lose effectiveness, and there are also problems such as slow ion exchange rate, incomplete elution, and poor recyclability. The ion exchange resin with a low exchange rate will cause the defects of long time consumption and high operation cost in the process of extracting Sc, which will reduce the processing efficiency of the solution containing high concentration of target elements. In addition, the traditional ion exchange method is not suitable for directly recovering scandium from a solution containing low concentration of scandium and high concentration of other elements (such as acid leaching solution of red mud), because there are a large number of pollutants in the solution, which will significantly reduce the effectiveness of the ion exchange resin. Based on the above defects, it is difficult for ion exchange technology to be widely used in scandium extraction. In addition, in the separation and purification technology of scandium, solvent extraction has the advantages of high extraction capacity, easy large-scale operation, etc., and is the most widely used technology for recovering trace scandium from a solution containing a large number of impurity elements. However, there are still some problems in the recovery of scandium by solvent extraction, such as complex circulation, loss of phosphorus-containing extractant, and formation of a large amount of emulsions, which requires the use of a large amount of organic solvents that affect the environment in the solvent extraction process. In addition, a large amount of organic solvents also has the potential safety hazard of fire, and additional engineering control is needed.

[0003] With the continuous deepening of the research on the separation and extraction of scandium, different methods can be combined to overcome the shortcomings of using a single method, such as combining adsorption and extraction techniques, and overcoming the above technical problems by preparing impregnated resins. However, due to the presence of a large amount of iron ions and other impurity metal ions in the scandium to be extracted, it is difficult to increase the scandium recovery rate to more than 90% by using the combined adsorption and extraction techniques at the present stage. SUMMARY

[0004] The present application provides a method for extracting scandium by combined extraction and adsorption to solve the technical problem of how to improve the scandium recovery rate during the combined use of adsorption and extraction techniques.

[0005] In a first aspect, the present application provides a method for extracting scandium by combined extraction and adsorption, which is used to extract scandium from a scandium-containing solution containing iron ions, and the method comprises the following steps:

[0006] performing a reduction reaction on the scandium-containing solution to reduce the iron ions to ferrous ions, thereby obtaining a pretreated solution containing scandium and ferrous ions;

[0007] performing a first resin adsorption on the pretreated solution using a phosphorus-containing impregnated resin to selectively adsorb the scandium in the pretreated solution and remove a small part of the ferrous ions in the pretreated solution, thereby obtaining a first adsorption resin rich in scandium and a de-scandium slurry containing less scandium; wherein the phosphorus-containing impregnated resin comprises an acidic cation adsorption resin and a phosphorus-containing extractant impregnated in the acidic cation adsorption resin;

[0008] performing a second resin adsorption on the de-scandium slurry using a chelating resin containing an amino carboxyl group to selectively adsorb the scandium in the de-scandium slurry containing less scandium and remove most of the ferrous ions in the pretreated solution, thereby obtaining a second adsorption resin rich in scandium;

[0009] respectively performing impurity removal treatment and desorption on the first adsorption resin and the second adsorption resin to obtain a scandium-rich eluate; and

[0010] performing purification treatment on the scandium-rich eluate to obtain a scandium product.

[0011] Optionally, the temperature of the first resin adsorption is 20℃-35℃, and the time of the first resin adsorption is 5h-20h; and / or

[0012] the temperature of the second resin adsorption is 50℃-80℃, and the time of the second resin adsorption is 20h-50h.

[0013] Optionally, the first resin adsorption and the second resin adsorption are respectively performed in a countercurrent contact mode, and the flow rate of the countercurrent contact is ≥0.5mL / min.

[0014] Optionally, the chelating resin containing amino-carboxyl group comprises a weakly acidic macroporous cation exchange resin containing aminomethyl phosphonic acid functional group.

[0015] Optionally, the preparation method of the phosphorus-containing impregnated resin comprises:

[0016] The acid cation adsorption resin is washed to remove impurities, and then the acid cation adsorption resin after the washing to remove impurities is dried to obtain a pretreated acid cation adsorption resin;

[0017] The phosphorus-containing extractant and the pretreated acid cation adsorption resin are mixed by oscillation to allow the phosphorus-containing extractant to infiltrate into the pretreated acid cation adsorption resin, thereby obtaining a crude phosphorus-containing impregnated resin;

[0018] The crude phosphorus-containing impregnated resin is subjected to negative pressure distillation to obtain a phosphorus-containing impregnated resin.

[0019] Optionally, the acid cation adsorption resin comprises at least one of the following: a phenyl strong acid resin, a cross-linked polystyrene-based macroporous resin, and a TVEX resin.

[0020] The phosphorus-containing extractant comprises tributyl phosphate and a phosphorus-containing component, and the phosphorus-containing component comprises at least one of the following: bis(2,4,4-trimethylpentyl) phosphonic acid, diisooctyl methyl phosphonate, and di(2-ethylhexyl) phosphate.

[0021] Optionally, the reducing agent used in the reduction reaction comprises sodium sulfite; and / or

[0022] The time of the reduction reaction is 30 min to 60 min.

[0023] Optionally, the separately removing impurities and desorbing the first adsorption resin and the second adsorption resin to obtain a scandium-rich eluent comprises the following steps:

[0024] The first adsorption resin and the second adsorption resin are separately washed to remove impurities using a washing solution to obtain a first impurity-removed resin and a second impurity-removed resin.

[0025] The first impurity-removed resin and the second impurity-removed resin are pre-desorbed using a dilute ammonia solution to obtain a first pre-desorbed resin and a second pre-desorbed resin.

[0026] The first pre-desorbed resin and the second pre-desorbed resin are separately desorbed using an eluent and combined to obtain a scandium-rich eluent.

[0027] Optionally, the washing solution comprises a sulfuric acid washing solution containing ammonium chloride and / or distilled water; and / or

[0028] The temperature of the washing to remove impurities is 80°C to 95°C; and / or

[0029] The flow rate of the eluent is ≥ 2 mL / cm 2 ; and / or

[0030] The temperature of the desorption is ≤ 80℃.

[0031] Optionally, the purification treatment of the Sc-rich eluent to obtain a Sc product comprises the steps of:

[0032] Mixing the alkali solution with the Sc-rich eluent and solid-liquid separation, and then dissolving the precipitate obtained by the solid-liquid separation to obtain a Sc-rich solution;

[0033] Mixing the organic acid solution with the Sc-rich solution to form a precipitate of Sc in the Sc-rich solution to obtain a Sc product.

[0034] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art:

[0035] The method for extracting and adsorbing and separating Sc provided by the embodiments of the present application first reduces the Sc-containing solution to convert the iron ions in the Sc-containing solution into ferrous ions, and then uses the phosphorus-containing impregnated resin for first resin adsorption of the pretreated solution. Based on the fact that the phosphorus-containing impregnated resin includes an acid cation adsorption resin and an extractant impregnated in the acid cation adsorption resin, the specific adsorption of the extractant of the phosphorus-containing impregnated resin to Sc is used to improve the speed of adsorption of the acid cation adsorption resin to Sc in the pretreated solution, so as to reduce the probability of adsorption of the acid cation adsorption resin to ferrous ions, thereby promoting the phosphorus-containing impregnated resin to selectively adsorb Sc in the pretreated solution without adsorbing ferrous ions, so as to preliminarily improve the recovery rate of Sc in the Sc-containing solution. In addition, the chelating resin containing aminocarboxyl is used for second resin adsorption, and the amino and carboxyl on the chelating resin containing aminocarboxyl can accurately identify and capture a large amount of Sc in the pretreated solution without combining with ferrous ions, so as to selectively adsorb a large amount of Sc in the pretreated solution without adsorbing ferrous ions, thereby improving the recovery rate of Sc in the Sc-containing solution. Therefore, the method reduces the Sc-containing solution by using a reducing agent, and then uses the phosphorus-containing impregnated resin and the chelating resin containing aminocarboxyl in series, which can maximize the recovery of Sc in the Sc-containing solution and improve the recovery rate of Sc in the Sc-containing solution. BRIEF DESCRIPTION OF DRAWINGS

[0036] The accompanying drawings, which are incorporated herein and constitute part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0038] Figure 1 A flow chart of a method for extracting and separating tantalum by combined extraction and adsorption provided by the embodiment of the present application;

[0039] Figure 2 A detailed flow chart of a method for extracting and separating tantalum by combined extraction and adsorption provided by the embodiment of the present application;

[0040] Figure 3 An actual flow chart of a method for extracting and separating tantalum by combined extraction and adsorption provided by the embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will combine the drawings in the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of protection of the present application.

[0042] The various embodiments of the present application can exist in the form of a range; it should be understood that the description in the form of a range is only for the convenience and brevity, and should not be understood as a hard limit to the scope of the present application; therefore, it should be considered that the described range has specifically disclosed all possible sub-ranges and single values in the range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers in the range, such as 1, 2, 3, 4, 5 and 6, which is applicable to any range; in addition, whenever a numerical range is indicated in the present text, it refers to any cited number (fraction or integer) in the indicated range.

[0043] In this document, the terms "comprises", "comprising", "includes", "including" or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, includes or includes elements or steps do not include only those elements or steps but can include other elements or steps not expressly listed or inherent to such process, method, article, or apparatus. The terms "first", "second", "third", etc. are used to identify different entities, but do not necessarily require these entities to be in a temporal or spatial sequence. The term "and / or" describes the associated relationship of associated objects, which means that there can be three relationships, for example, A and / or B, which means that A exists alone, A and B exist together, B exists alone; wherein A and B can be singular or plural. "At least one" means one or more, "multiple" means two or more; "at least one" or "at least one of the following" or the like means any combination of the items, including single or multiple combinations; for example, "at least one of a, b, or c", or "at least one of a, b, and c", can mean a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, wherein a, b, and c can be single or multiple. The "parts ratio" such as weight parts, mass parts, etc. represents the proportional relationship between components. In the proportional relationship described herein, the parameters that need to be described by the proportion should be understood as the front item of the proportional formula in the order of description, and the proportional number should be understood as the latter item of the proportional formula, for example, the mass ratio of substance A, substance B and substance C is 1:2:3, then substance A, substance B and substance C should be corresponding to the proportional number in the proportional formula according to the description order, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0044] Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in this document can be purchased from the market or prepared by existing methods.

[0045] Figure 1 An exemplary flowchart of a method for extracting and separating scandium by combined extraction and adsorption provided by the embodiments of the present application is shown;

[0046] As shown in Figure 1 The embodiments of the present application provide a method for extracting and separating scandium by combined extraction and adsorption, which is used for extracting scandium from a scandium-containing solution containing iron ions, and the method comprises the following steps:

[0047] S1. Using a reducing agent to reduce the scandium-containing solution to reduce the iron ions to ferrous ions, to obtain a pretreated solution containing scandium and ferrous ions;

[0048] S2. using a phosphorus-containing impregnated resin, performing first resin adsorption on the pretreated solution to selectively adsorb scandium in the pretreated solution and remove a small part of ferrous ions in the pretreated solution, to obtain a first adsorption resin rich in scandium and a de-scandium slurry containing less scandium; wherein the phosphorus-containing impregnated resin comprises an acidic cation adsorption resin, and a phosphorus-containing extractant impregnated in the acidic cation adsorption resin;

[0049] S3. using a chelating resin containing aminocarboxyl, performing second resin adsorption on the de-scandium slurry to selectively adsorb scandium in the de-scandium slurry containing less scandium and remove most of the ferrous ions in the pretreated solution, to obtain a second adsorption resin rich in scandium;

[0050] S4. respectively performing impurity removal treatment and desorption on the first adsorption resin and the second adsorption resin, to obtain a scandium-rich eluate; and

[0051] S5. performing purification treatment on the scandium-rich eluate, to obtain a scandium product.

[0052] It should be noted that the reducing agent can use sulfite, which not only can convert iron ions in the scandium-containing solution into ferrous ions to reduce the risk of interference of iron ions in the subsequent first resin adsorption and second resin adsorption process, but also can remove other metal ion impurities in the scandium-containing solution (such as calcium ions) by combining sulfite ions with other metal ion impurities in the scandium-containing solution, to further improve the scandium recovery rate of the scandium-containing solution.

[0053] It should be noted that the source of the scandium-containing solution can be an acid leaching solution of red mud, can be fly ash, can be rare earth, can be a hydrolysis sulfuric acid solution of titanium dioxide, can be a hydrolysis hydrochloric acid solution of titanium dioxide, can be a dissolution solution prepared from nickel laterite ore, or can be a dissolution solution prepared from industrial waste residue.

[0054] It should be noted that the pH of the scandium-containing solution can be 2-3.5.

[0055] It should be noted that the first resin adsorption is based on the specific adsorption of the extractant of the phosphorus-containing impregnated resin to the scandium in the pretreated solution, which can quickly adsorb the scandium in the pretreated solution, but the adsorption amount of this adsorption process is limited, so it is necessary to perform second resin adsorption by the chelating resin containing aminocarboxyl to accurately identify and capture a large amount of scandium in the pretreated solution, so as to adsorb a large amount of scandium in the de-scandium slurry.

[0056] It should be noted that the eluent used in the desorption process can be a carbonate solution, or can be an acetate solution.

[0057] It is to be noted that the eluent of the desorption process can elute the phosphorus-containing impregnated resin or the amino-carboxyl-containing chelating resin from bottom to top to sufficiently elute the adsorbed scandium in the phosphorus-containing impregnated resin or the amino-carboxyl-containing chelating resin, so as to finally obtain the scandium-rich eluent.

[0058] It is to be noted that the first adsorption resin and the second adsorption resin after desorption can be respectively subjected to regeneration treatment and can be recycled.

[0059] It is to be noted that the scandium-removing slurry containing a large amount of iron can be obtained after the second resin adsorption treatment, and the iron element or the aluminum element in the scandium-removing slurry can be recovered.

[0060] In some optional embodiments, the temperature of the first resin adsorption is 20-35℃, and the time of the first resin adsorption is 5-20h; and / or

[0061] the temperature of the second resin adsorption is 50-80℃, and the time of the second resin adsorption is 20-50h.

[0062] In these embodiments, the temperature of the first resin adsorption can be 20-35℃, and the time of the first resin adsorption can be 5-20h, so as to enable the phosphorus-containing impregnated resin to have sufficient temperature and sufficient time to adsorb scandium in the pretreated solution to finally obtain the first adsorption resin; in addition, the temperature of the second resin adsorption can be 50-80℃, and the time of the second resin adsorption can be 20-50h, so as to enable the amino-carboxyl-containing chelating resin to have sufficient temperature and sufficient time to adsorb scandium in the scandium-removing slurry containing less scandium to finally obtain the second adsorption resin.

[0063] The temperature of the first resin adsorption can be 20℃, 22℃, 24℃, 26℃, 28℃, 30℃, 32℃, 34℃ or 35℃.

[0064] The time of the first resin adsorption can be 5h, 10h, 15h or 20h.

[0065] The temperature of the second resin adsorption can be 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃.

[0066] The time of the second resin adsorption can be 20h, 25h, 30h, 35h, 40h, 45h or 50h.

[0067] In some optional embodiments, the first resin adsorption and the second resin adsorption are respectively performed in a countercurrent contact mode, and the flow rate of the countercurrent contact is ≥0.5mL / min.

[0068] In these embodiments, the first resin adsorption and the second resin adsorption can be performed by counter-current contact, and the flow rate of the counter-current contact is ≥ 0.5 mL / min. The counter-current contact can facilitate the pretreated solution to fully contact the phosphorus-containing impregnated resin and the amino-carboxyl-containing chelating resin, so that the scandium in the scandium-containing solution can effectively enter the phosphorus-containing impregnated resin and the amino-carboxyl-containing chelating resin, thereby facilitating the subsequent desorption to obtain scandium products with sufficient purity and recovery rate.

[0069] In some alternative embodiments, the amino-carboxyl-containing chelating resin comprises a weakly acidic macroporous cation exchange resin containing aminomethyl phosphonic acid functional group.

[0070] In these embodiments, the amino-carboxyl-containing chelating resin can comprise a weakly acidic macroporous cation exchange resin containing aminomethyl phosphonic acid functional group. The weakly acidic macroporous cation exchange resin containing aminomethyl phosphonic acid functional group can accurately identify and capture scandium in the complex scandium-lean de-scandium slurry containing multiple metal ions, and is also not disturbed by other non-target ions, so that the scandium in the pretreated solution can be selectively adsorbed in a large amount without adsorbing ferrous ions, thereby improving the recovery rate of scandium in the scandium-containing solution.

[0071] It should be noted that the amino-carboxyl-containing chelating resin can be chelating resin TP260. The chelating resin TP260 can selectively remove alkaline earth metal cations. In addition, the individual dispersed particles of the chelating resin TP260 have excellent mechanical and osmotic stability, which makes the chelating resin TP260 have more excellent kinetic characteristics compared with non-uniformly dispersed ion exchange resins, so that the chelating resin TP260 has a higher working exchange capacity. In addition, based on the good chemical stability and mechanical strength of the chelating resin TP260, it can be used in high-concentration acid, alkali or salt solutions without degradation or failure. In addition, the chelating resin TP260 also has high regeneration capacity. After regeneration treatment with a proper regenerant, the adsorption performance of the chelating resin TP260 can be restored and the chelating resin TP260 can be recycled.

[0072] Figure 2 An example of a detailed flow diagram of a method for extracting scandium by combined extraction and adsorption separation provided by an embodiment of the present application is shown;

[0073] Figure 3 An example of a detailed flow diagram of a method for extracting scandium by combined extraction and adsorption separation provided by an embodiment of the present application is shown;

[0074] In some alternative embodiments, as shown in Figure 2 and Figure 3 The preparation method of the phosphorus-containing impregnated resin comprises:

[0075] S101. Washing the acid cation adsorption resin to remove impurities, and then drying the acid cation adsorption resin after the removal of impurities to obtain a pretreated acid cation adsorption resin;

[0076] S102. Oscillating and mixing the phosphorus-containing extractant and the pretreated acid cation adsorption resin to infiltrate the phosphorus-containing extractant into the pretreated acid cation adsorption resin to obtain a crude phosphorus-containing impregnated resin;

[0077] S103. Distilling the crude phosphorus-containing impregnated resin under negative pressure to obtain a phosphorus-containing impregnated resin;

[0078] In these embodiments, the acid cation adsorption resin is pretreated to remove impurities on the surface, and then the oscillating and mixing of the phosphorus-containing extractant and the pretreated acid cation adsorption resin can infiltrate the phosphorus-containing extractant into the pretreated acid cation adsorption resin, so that the phosphorus-containing impregnated resin infiltrated by the extractant can be obtained, and finally the diluent component of the extractant can be removed by distillation under negative pressure to obtain the pure phosphorus-containing impregnated resin.

[0079] It should be noted that the drying can be performed at low temperature to dry to a constant weight.

[0080] It should be noted that the oscillating and mixing time can be 12 h.

[0081] It should be noted that the adsorption amount of the phosphorus-containing extractant on the pretreated acid cation adsorption resin is related to the type of acid cation adsorption resin, so the phosphorus-containing extractant needs to be excessive relative to the acid cation adsorption resin.

[0082] In some optional embodiments, the acid cation adsorption resin comprises at least one of the following: a phenyl strong acid resin, a cross-linked polystyrene-based macroporous resin, and a TVEX resin;

[0083] The phosphorus-containing extractant comprises tributyl phosphate and a phosphorus-containing component, and the phosphorus-containing component comprises at least one of the following: bis(2,4,4-trimethylpentyl) phosphinic acid, diisooctyl methyl phosphonate, and di(2-ethylhexyl) phosphate;

[0084] In these embodiments, the acidic cation adsorption resin can include at least one of a phenyl strong acid resin, a cross-linked polystyrene-based macroporous resin, and a TVEX resin, and the phosphorus-containing extractant can include tributyl phosphate and a phosphorus-containing component, and the phosphorus-containing component can include at least one of bis(2,4,4-trimethylpentyl) phosphinic acid, diisooctyl methyl phosphonate, and di(2-ethylhexyl) phosphate, to facilitate the acidic cation adsorption resin to adsorb a sufficient amount of the phosphorus-containing extractant, which can increase the speed of the acidic cation adsorption resin to adsorb scandium in the pretreated solution, to reduce the probability of the acidic cation adsorption resin to adsorb ferrous ions, so that the phosphorus-containing impregnated resin can be facilitated to selectively adsorb scandium in the pretreated solution without adsorbing ferrous ions, to preliminarily improve the recovery rate of scandium in the scandium-containing solution.

[0085] It should be noted that the phenyl strong acid resin can be a phenyl strong acid resin Dowex 50-X8, and the pore size of the phenyl strong acid resin Dowex 50-X8 can be 100-200 mesh; the TVEX resin can be a TVEX-TOPO resin, or a TVEX-PHOR, or a TVEX-DIOMP.

[0086] In some optional embodiments, the reducing agent includes sodium sulfite; and / or

[0087] The time of the reduction reaction is 30-60 min;

[0088] In these embodiments, the reducing agent can include sodium sulfite, and the time of the reduction reaction can be 30-60 min, and the iron ions in the scandium-containing solution can be reduced to ferrous ions by the sodium sulfite, at this time, the sulfite ions are converted into sulfate ions, and the converted sulfate ions can also react with calcium ions in the scandium-containing solution to generate calcium sulfate precipitates in a long enough reduction reaction stage, and the calcium sulfate component can be separated from the scandium-containing solution by solid-liquid separation, so as to realize the reduction of the iron ions and the removal of the calcium ions.

[0089] In some optional embodiments, the separately removing impurities and desorbing the first adsorption resin and the second adsorption resin to obtain a scandium-rich eluate includes the steps of:

[0090] S401. Using the eluent to separately elute and remove impurities from the first adsorption resin and the second adsorption resin to obtain a first impurity-removed resin and a second impurity-removed resin;

[0091] S402. Using a dilute ammonia solution to pre-desorb the first impurity-removed resin and the second impurity-removed resin to obtain a first pre-desorption resin and a second pre-desorption resin;

[0092] S403. desorbing the first pre-desorption resin and the second pre-desorption resin respectively using an eluent and combining the first pre-desorption resin and the second pre-desorption resin to obtain a rich scandium eluent;

[0093] In these embodiments, the first adsorption resin and the second adsorption resin are first leached using a leaching solution to remove impurities from the first adsorption resin and the second adsorption resin to obtain a first impurity-removed resin and a second impurity-removed resin; then the first impurity-removed resin and the second impurity-removed resin are pre-desorbed using a dilute ammonia solution, and the basic molecules of the dilute ammonia solution preliminarily occupy the penetration channels of the first impurity-removed resin and the second impurity-removed resin, which can reduce the risk of subsequent eluent penetrating into the first impurity-removed resin and the second impurity-removed resin, avoid the flow state phenomenon of phosphorus-containing impregnated resins or amino carboxyl-containing chelating resins, and thus prolong the service life of these resins; finally, the first pre-desorption resin and the second pre-desorption resin are desorbed and combined using an eluent, which can effectively elute the scandium from the first pre-desorption resin and the second pre-desorption resin without damaging the resin body.

[0094] In some optional embodiments, the leaching solution comprises a sulfuric acid leaching solution containing ammonium chloride and / or distilled water; and / or

[0095] The leaching temperature is 80-95°C; and / or

[0096] The flow rate of the leaching solution is ≥2 mL / cm 2 ; and / or

[0097] The desorption temperature is ≤80°C;

[0098] In these embodiments, the first adsorption resin and the second adsorption resin are leached using a sulfuric acid solution containing ammonium chloride, and the ammonium chloride can change the oxidation potential of the leaching solution, thereby promoting the removal of impurities; in addition, the leaching temperature can be 80-95°C, which can reduce the dissolution of scandium in the leaching solution from the first adsorption resin and the second adsorption resin during the leaching stage, and reduce the loss of scandium during the leaching stage; in addition, the flow rate of the leaching solution is ≥2 mL / cm 2 , and a faster flow rate of the leaching solution can effectively dissolve the impurities adsorbed by the first adsorption resin and the second adsorption resin into the leaching solution to effectively remove the impurities from the first adsorption resin and the second adsorption resin; in addition, the desorption temperature is ≤80°C, which can promote the dissolution of scandium in the eluent from the first adsorption resin and the second adsorption resin to remove the scandium from the first adsorption resin and the second adsorption resin.

[0099] The leaching temperature can be 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, 93°C, 94°C, or 95°C.

[0100] It should be noted that in the case of the temperature of the elution impurity removal being less than 80℃, scandium will dissolve into the elution liquid, causing the scandium of the first adsorption resin and the second adsorption resin to dissolve into the elution liquid, resulting in loss of scandium; in the case of the temperature of the elution impurity removal being greater than 95℃, the first adsorption resin and the second adsorption resin will also adsorb other metal ion impurities, which will reduce the purity of the recovered scandium.

[0101] In some optional embodiments, the purification treatment of the scandium-rich elution liquid to obtain the scandium product comprises the following steps:

[0102] S501. Mixing the alkali liquid with the scandium-rich elution liquid and performing solid-liquid separation, and then dissolving the precipitate obtained by the solid-liquid separation to obtain a scandium-rich solution;

[0103] S502. Mixing the organic acid solution with the scandium-rich solution to form a precipitate of scandium in the scandium-rich solution to obtain a scandium product;

[0104] In these embodiments, by mixing the alkali liquid with the scandium-rich elution liquid and performing solid-liquid separation, the scandium in the scandium-rich elution liquid is converted into a precipitate by the alkali liquid, and then the precipitate is dissolved, so that a scandium-rich solution can be obtained; then the scandium in the scandium-rich solution is separated from the scandium-rich solution in the form of a precipitate by the organic acid, so that a scandium product is obtained.

[0105] It should be noted that the alkali liquid can be a carbonate solution or an acetate solution.

[0106] It should be noted that the organic acid solution can be an oxalic acid solution or a tartaric acid solution; in the case of the organic acid solution being an oxalic acid solution, the obtained scandium product can be scandium oxalate.

[0107] It should be noted that the solvent of the oxalic acid solution and the tartaric acid solution can be ethanol with the same amount of substance as oxalic acid or tartaric acid and the like.

[0108] The present application will be further described below in conjunction with specific examples. The experimental methods in the following examples are not specified, and are generally determined according to national standards / industry standards; if there is no corresponding national standard / industry standard, the general international standard, conventional conditions or the conditions recommended by the manufacturer are used.

[0109] Example 1

[0110] The pH value of the scandium-containing solution is adjusted to 3 using the red mud acid leaching liquid, and the scandium mass concentration of the scandium-containing solution is 0.01 g / L.

[0111] A method for extracting scandium from a scandium-containing solution containing iron ions, comprising:

[0112] S101. First, the cation adsorption resin is flushed with 2M NaOH solution, then washed with deionized water until neutral, and then the cation adsorption resin is contacted with 1M HCl in a shaker for 2h, so that the cation adsorption resin is converted into the proton form (H + ), and the acidic cation adsorption resin needs to be dried overnight in air before use;

[0113] The acidic cation adsorption resin is washed with anhydrous ethanol for about 5h to remove the pore-forming agent, catalyst, reaction solvent and other impurities contained therein, and then the acidic cation adsorption resin is washed with distilled water until neutral, and the above operation steps are repeated 3 times; after the acidic cation adsorption resin is filtered out, it is dried in a drying oven at a temperature of 50-60℃ until the weight is constant, to obtain the pretreated acidic cation adsorption resin;

[0114] S102. Take 100g of the acidic cation adsorption resin and put it into a conical flask, then add 500mL of the fully dissolved extractant, seal the flask with a rubber plug, and shake in a shaker for 12h, so that the phosphorus-containing extractant is impregnated into the pretreated acidic cation adsorption resin, to obtain a crude phosphorus-containing impregnated resin;

[0115] S103. The crude phosphorus-containing impregnated resin is subjected to negative pressure distillation to remove the diluent, to obtain the phosphorus-containing impregnated resin;

[0116] S1. The scandium-containing solution is subjected to reduction reaction using 0.2g / L of a reducing agent, so that the iron ions are reduced to ferrous ions, to obtain a pretreated solution;

[0117] S2. The pretreated solution is subjected to first resin adsorption using the phosphorus-containing impregnated resin, to selectively adsorb the scandium in the pretreated solution and remove a small part of the ferrous ions in the pretreated solution, to obtain a first adsorption resin rich in scandium and a scandium-removed slurry containing a small amount of scandium; wherein the phosphorus-containing impregnated resin comprises an acidic cation adsorption resin and a phosphorus-containing extractant impregnated in the acidic cation adsorption resin;

[0118] S3. The scandium-removed slurry containing a small amount of scandium is subjected to second resin adsorption using a chelating resin containing an amino carboxyl group, to selectively adsorb the scandium in the scandium-removed slurry containing a small amount of scandium and remove most of the ferrous ions in the pretreated solution, to obtain a second adsorption resin and a scandium-removed slurry containing no scandium;

[0119] S401. The first adsorption resin and the second adsorption resin are respectively subjected to impurity removal leaching using a sulfuric acid leaching solution (mass concentration 49g / L) containing ammonium chloride, then the leaching solution is subjected to degassing treatment after slow heating, and then the first adsorption resin and the second adsorption resin are respectively obtained using distilled water, to obtain a first impurity-removed resin and a second impurity-removed resin;

[0120] S402. Pre-desorbing the first impurity-removing resin and the second impurity-removing resin using ammonia water with a mass concentration of 50 g / L, controlling the flow rate of the ammonia water to be 1 BV / h, to obtain a first pre-desorbed resin and a second pre-desorbed resin;

[0121] S403. Desorbing the first pre-desorbed resin and the second pre-desorbed resin respectively using sodium carbonate solution with a mass concentration of 180 g / L as an eluent, controlling the flow rate of the eluent to be 1 BV / h, and combining the eluent to obtain a scandium-rich eluent;

[0122] S501. Mixing the alkali solution and the scandium-rich eluent thoroughly, adding the alkali solution with a mass concentration of 3.5 mol / L at a volume of 1 / 5 of the volume of the scandium-rich eluent, then performing solid-liquid separation, and dissolving the precipitate obtained by the solid-liquid separation to obtain a scandium-rich solution;

[0123] S502. Mixing the oxalic acid solution and the scandium-rich solution to form a precipitate of scandium oxalate from the scandium-rich solution to obtain a scandium oxalate product. The temperature of the first resin adsorption is 25℃, and the time of the first resin adsorption is 10h.

[0124] The temperature of the second resin adsorption is 80℃, and the time of the second resin adsorption is 35h.

[0125] The first resin adsorption and the second resin adsorption are performed in a countercurrent contact manner, and the flow rate of the countercurrent contact is ≥0.5 mL / min.

[0126] The chelating resin containing an amino carboxyl group includes a weakly acidic macroporous cation exchange resin containing an aminomethyl phosphonic acid functional group.

[0127] The acidic cation adsorption resin includes at least one of the following: a phenyl strong acid resin, a cross-linked polystyrene-based macroporous resin, and a TVEX resin;

[0128] The phosphorus-containing extractant includes tributyl phosphate and a phosphorus-containing component, and the phosphorus-containing component is di(2-ethylhexyl) phosphate; the volume V1 of the tributyl phosphate and the volume V2 of the phosphorus-containing component satisfy the relationship V1:V2=5%:15%.

[0129] The reducing agent includes sodium sulfite;

[0130] The time of the reduction reaction is 30 min.

[0131] The eluent includes sulfuric acid eluent containing ammonium chloride and distilled water;

[0132] The temperature of the elution impurity removal is 80℃-95℃;

[0133] The flow rate of the eluent is 2 mL / cm 2 ;

[0134] The temperature of desorption is 80℃.

[0135] Example 2

[0136] Based on the disclosure of Example 1, the following modifications are further made:

[0137] The pH of the solution containing scandium is adjusted to 2.

[0138] Example 3

[0139] Based on the disclosure of Example 1, the following modifications are further made:

[0140] The red mud acid leaching solution is used as the solution containing scandium, and the mass concentration of scandium is 0.0054g / L.

[0141] Example 4

[0142] Based on the disclosure of Example 1, the following modifications are further made:

[0143] The temperature of the first resin adsorption is 35℃, and the time of the first resin adsorption is 10h;

[0144] The temperature of the second resin adsorption is 50℃, and the time of the second resin adsorption is 30h.

[0145] Example 5

[0146] Based on the disclosure of Example 1, the following modifications are further made:

[0147] The temperature of the first resin adsorption is 30℃, and the time of the first resin adsorption is 5h;

[0148] The temperature of the second resin adsorption is 65℃, and the time of the second resin adsorption is 20h.

[0149] Example 6

[0150] Based on the disclosure of Example 1, the following modifications are further made:

[0151] Tartaric acid is used instead of oxalic acid.

[0152] Comparative Example 1

[0153] Based on the disclosure of Example 1, the following modifications are further made:

[0154] The phosphorus-containing impregnated resin is not used, and the chelating resin is used for both resin adsorptions.

[0155] Comparative Example 2

[0156] Based on the disclosure of Example 1, the following modifications are further made:

[0157] The two resin adsorptions do not use chelating resin, and use phosphorus-containing impregnated resin.

[0158] Comparative Example 3

[0159] Based on the disclosure of Example 1, the following modifications are further made:

[0160] The pH of the scandium-containing solution is adjusted to 1.

[0161] Comparative Example 4

[0162] Based on the disclosure of Example 1, the following modifications are further made:

[0163] The temperature of the first resin adsorption is 10℃, and the time of the first resin adsorption is 30h;

[0164] The temperature of the second resin adsorption is 40℃, and the time of the second resin adsorption is 60h.

[0165] Comparative Example 5

[0166] Based on the disclosure of Example 1, the following modifications are further made:

[0167] The temperature of the first resin adsorption is 45℃, and the time of the first resin adsorption is 3h;

[0168] The temperature of the second resin adsorption is 90℃, and the time of the second resin adsorption is 10h.

[0169] Related experiments and effect data:

[0170] The scandium recovery rate of the scandium-rich eluent and the scandium recovery rate of the scandium product in each example and comparative example are counted respectively, and the results are shown in Table 1.

[0171] Table 1: Scandium recovery rate of each example and comparative example

[0172]

[0173]

[0174] As shown in Table 1, the method for jointly extracting and adsorbing and separating scandium provided by the embodiments of the present application can maximize the recovery of scandium in the scandium-containing solution and improve the scandium recovery rate of the scandium-containing solution to more than 90% by using phosphorus-containing impregnated resin and amino carboxyl-containing chelating resin in series after reducing the scandium-containing solution. In addition, the method can recover more than 90% of scandium from the scandium-rich eluent and generate scandium products.

[0175] In addition, the method for extracting scandium by combined extraction and adsorption separation provided by the embodiment of the present application uses the phosphorus-containing extractant to cooperate with the acidic cation resin to accurately extract scandium from the scandium-containing solution, can greatly reduce the use of organic solvents, and does not need to dilute the liquid extractant with the organic solvents, so that the method does not have the phase separation problem, and the method needs simple equipment, has smaller factory area, and has lower production cost.

[0176] In addition, the method for extracting scandium by combined extraction and adsorption separation provided by the embodiment of the present application can fully recover a large amount of scandium from the scandium-containing solution, and can efficiently remove trace impurities in the scandium-containing solution, can ensure the purity of scandium in the case of recovering scandium to the maximum, and provides an efficient and reliable solution for solving the metal ion pollution problem in the industrial process.

[0177] The above only is the specific embodiment of the present application, and enables the person skilled in the art to understand or implement the present application. Various modifications of the embodiments will be apparent to those skilled in the art, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown in the present application, but will conform to the widest range consistent with the principles and novel features applied in the present application.

Claims

1. A method for extracting scandium from a scandium-containing solution containing iron ions by combined extraction and adsorption, the method comprising: reducing the scandium-containing solution to reduce the iron ions to ferrous ions to obtain a pretreated solution containing scandium and ferrous ions, wherein the pH of the scandium-containing solution is 2-3.5; using a phosphorus-containing impregnated resin to perform first resin adsorption on the pretreated solution to selectively adsorb scandium in the pretreated solution and remove a small amount of ferrous ions in the pretreated solution, thereby obtaining a first adsorption resin rich in scandium and a scandium-removed slurry containing less scandium; wherein the phosphorus-containing impregnated resin comprises an acidic cation adsorption resin and a phosphorus-containing extractant impregnated in the acidic cation adsorption resin; using a chelating resin containing aminocarboxyl to perform second resin adsorption on the scandium-removed slurry containing less scandium to selectively adsorb scandium in the scandium-removed slurry containing less scandium and remove most of the ferrous ions in the pretreated solution, thereby obtaining a second adsorption resin rich in scandium; using an eluent to perform elution impurity removal on the first adsorption resin and the second adsorption resin, respectively, to obtain a first elution impurity removal resin and a second elution impurity removal resin; using a dilute ammonia solution to perform pre-desorption on the first elution impurity removal resin and the second elution impurity removal resin, thereby obtaining a first pre-desorption resin and a second pre-desorption resin; using an eluting agent to perform desorption on the first pre-desorption resin and the second pre-desorption resin, respectively, and combining the first pre-desorption resin and the second pre-desorption resin, thereby obtaining a scandium-rich eluting agent; and performing purification treatment on the scandium-rich eluting agent to obtain a scandium product; wherein the temperature of the first resin adsorption is 20-35℃, and the temperature of the second resin adsorption is 50-80℃; the acidic cation adsorption resin comprises at least one of the following: a phenyl strong acid resin, a cross-linked polystyrene-based macroporous resin, and a TVEX resin; the phosphorus-containing extractant comprises tributyl phosphate and a phosphorus-containing component, and the phosphorus-containing component comprises at least one of the following: bis (2, 4, 4-trimethylpentyl) phosphonic acid, diisooctyl methyl phosphonate, and di (2-ethylhexyl) phosphate; the chelating resin containing aminocarboxyl comprises a weakly acidic macroporous cation exchange resin containing aminomethyl phosphonic acid functional group; the eluent comprises a sulfuric acid eluent containing ammonium chloride and / or distilled water; the temperature of the elution impurity removal is 80-95℃; and the eluting agent is a carbonate solution or an acetate solution. 2.The method of claim 1, wherein the time of the first resin adsorption is 5-20 hours; and / or the time of the second resin adsorption is 20-50 hours. 3.The method of claim 1, wherein the first resin adsorption and the second resin adsorption are performed by countercurrent contact, and the flow rate of the countercurrent contact is ≥0.5 mL / min. 4.The method of claim 1, wherein the preparation method of the phosphorus-containing impregnated resin comprises: washing and impurity removal of an acidic cation adsorption resin, and then drying the acidic cation adsorption resin after the washing and impurity removal, thereby obtaining a pretreated acidic cation adsorption resin. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The phosphorus-containing extractant and the pretreated acidic cation adsorption resin are mixed by oscillation to infiltrate the phosphorus-containing extractant into the pretreated acidic cation adsorption resin, to obtain a crude phosphorus-containing impregnated resin; The crude phosphorus-containing impregnated resin is subjected to negative pressure distillation, to obtain a phosphorus-containing impregnated resin.

5. The method according to claim 1, wherein the reducing agent used in the reduction reaction comprises sodium sulfite; and / or The time of the reduction reaction is 30 min to 60 min.

6. The method of claim 1, the flow rate of the eluent is > 2 mL / cm 2 ; and / or The temperature of the desorption is ≤ 80 ℃.

7. The method according to claim 1, wherein the purification treatment of the scandium-rich eluate to obtain a scandium product comprises the steps of: mixing a lye with the scandium-rich eluate and performing solid-liquid separation, and then dissolving the precipitate obtained by the solid-liquid separation to obtain a scandium-rich solution; mixing an organic acid solution with the scandium-rich solution to form a precipitate of scandium in the scandium-rich solution, to obtain a scandium product.

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