Method for separating and extracting scandium by combined adsorption and extraction technology

Abstract

The invention relates to the technical field of hydrometallurgy, in particular to a method for extracting scandium through combined extraction, adsorption and separation. The method is used for extracting scandium in a scandium-containing solution containing iron ions, and comprises the following steps: carrying out reduction reaction on the scandium-containing solution by using a reducing agent to obtain a pretreatment solution; adsorbing the first resin of the pretreatment solution by using phosphorus-containing impregnating resin to obtain first adsorption resin and scandium-removed slurry; wherein the phosphorus-containing impregnating resin comprises acidic cation adsorption resin and a phosphorus-containing extraction agent; adsorbing the scandium-removed slurry with second resin by using chelate resin containing amino carboxyl to obtain second adsorption resin; respectively carrying out impurity removal treatment and desorption on the first adsorption resin and the second adsorption resin to obtain scandium-rich eluent; and purifying the scandium-rich eluent to obtain a scandium product. According to the method, the scandium-containing solution is subjected to reduction treatment through the reducing agent, then the phosphorus-containing impregnating resin and the chelating resin are connected in series for adsorbing scandium in the scandium-containing solution, and the scandium in the scandium-containing solution can be recycled to the maximum extent.

Description

Technical Field

[0001] The present application relates to the technical field of hydrometallurgy, and in particular to a method for extracting scandium through combined extraction, adsorption and separation. Background Art

[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 complicated, 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. When certain ions in the liquid phase are preferred by the ion exchange solid, these ions will be adsorbed by the ion exchange solid, but in order to maintain the electrical neutrality of the aqueous solution, the ion exchange solid must release equivalent ions back to the solution. Based on the strong chemical activity of Sc, Sc can be separated from other elements by strong acid cation exchange resin, and when the ion exchange solid is subsequently eluted with sulfuric acid, Sc may form sulfate complex anions with sulfuric acid. However, ion exchange resins generally use volatile organic solvents. In the process of extracting Sc, volatile organic solvents will cause the extraction process of Sc to be easily doped with impurities. Based on this shortcoming, ionic liquids (ILs) can be used to replace traditional volatile organic solvents. ILs are a solvent composed entirely of ions and have been studied as a non-volatile substitute for organic solvents. However, ion exchange resins containing ILs are easily oxidized and become ineffective, and there are also problems such as slow ion exchange rate, incomplete elution, and poor recyclability. Ion exchange resins with lower exchange rates will lead to the defects of long time and high operating cost in the Sc extraction process, which will reduce the processing efficiency of solutions containing high concentrations of target elements. In addition, traditional ion exchange methods are not suitable for directly recovering scandium from solutions with low scandium concentrations and high concentrations of other elements (such as acid leaching solutions of red mud) because these solutions contain a large amount of pollutants, which will significantly reduce the effectiveness of ion exchange resins. Based on the above-mentioned defects, ion exchange technology is difficult to be applied on a large scale in the extraction of scandium. In addition, in the separation and purification technology of scandium, solvent extraction is required to have the advantages of high extraction capacity and easy large-scale operation. This is currently the most widely used technology for recovering trace scandium from solutions containing a large amount of impurity elements. However, there are also some problems in the recovery of scandium by solvent extraction, such as complex circulation, loss of phosphorus-containing extractants and the formation of large amounts of emulsions. This requires the use of large amounts of organic solvents in the solvent extraction process, which affects the environment. Large amounts of organic solvents also pose fire safety hazards and require additional engineering controls.

[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 these methods when used alone. For example, adsorption and extraction techniques can be combined to prepare impregnated resins to overcome the above-mentioned technical problems. However, since some of the scandium to be extracted contains a large amount of iron ions and other impurity metal ions, it is difficult to increase the recovery rate of Sc to more than 90% by combining adsorption and extraction techniques at this stage. Summary of the invention

[0004] The present application provides a method for extracting scandium by combined extraction, adsorption and separation, in order to solve the following technical problem: how to improve the recovery rate of scandium in the process of combined use of adsorption and extraction technology.

[0005] In a first aspect, the present application provides a method for extracting scandium by combined extraction, adsorption and separation, for extracting scandium from a scandium-containing solution containing iron ions, the method comprising:

[0006] The scandium-containing solution is subjected to a reduction reaction to reduce the iron ions to ferrous ions, thereby obtaining a pretreatment solution containing scandium and ferrous ions;

[0007] Using a phosphorus-containing impregnating resin, subjecting the pretreatment solution to a first resin adsorption to selectively adsorb scandium in the pretreatment solution and remove a small portion of ferrous ions in the pretreatment solution, thereby obtaining a scandium-rich first adsorption resin and a scandium-removed slurry containing less scandium; wherein the phosphorus-containing impregnating resin comprises an acidic cationic adsorption resin and a phosphorus-containing extractant impregnated in the acidic cationic adsorption resin;

[0008] Using a chelating resin containing aminocarboxyl groups, subjecting the scandium-depleted slurry to a second resin adsorption to selectively adsorb scandium from the scandium-depleted slurry containing less scandium, and removing most of the ferrous ions from the pretreatment solution to obtain a scandium-rich second adsorption resin;

[0009] Respectively subjecting the first adsorption resin and the second adsorption resin to impurity removal and desorption to obtain a scandium-rich eluent; and

[0010] The scandium-rich eluate is purified to obtain a scandium product.

[0011] Optionally, the temperature of the first resin adsorption is 20° C. to 35° C., and the time of the first resin adsorption is 5 h to 20 h; and / or

[0012] The temperature for the second resin adsorption is 50° C. to 80° C., and the time for the second resin adsorption is 20 h to 50 h.

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

[0014] Optionally, the aminocarboxyl-containing chelating resin comprises a weakly acidic macroporous cation exchange resin containing an aminomethylphosphonic acid functional group.

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

[0016] The acidic cation adsorption resin is washed and impurity-removed, and then the acidic cation adsorption resin after washing and impurity-removal is dried to obtain a pretreated acidic cation adsorption resin;

[0017] The phosphorus-containing extractant and the pretreated acidic cation adsorption resin are vibrated and mixed so that the phosphorus-containing extractant is infiltrated into the pretreated acidic cation adsorption resin to obtain a crude phosphorus-containing impregnated resin;

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

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

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

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

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

[0023] Optionally, the first adsorption resin and the second adsorption resin are subjected to impurity removal and desorption respectively to obtain a scandium-rich eluent, comprising the steps of:

[0024] Using a washing liquid to wash and remove impurities from the first adsorption resin and the second adsorption resin, respectively, to obtain a first impurity-removing resin and a second impurity-removing resin;

[0025] Pre-desorbing the first impurity-removing resin and the second impurity-removing resin using a dilute ammonia solution to obtain a first pre-desorption resin and a second pre-desorption resin;

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

[0027] Optionally, the eluent includes a sulfuric acid eluent containing ammonium chloride and / or distilled water; and / or

[0028] The temperature of the elution and impurity removal is 80°C to 95°C; and / or

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

[0030] The desorption temperature is ≤80°C.

[0031] Optionally, the scandium-rich eluate is purified to obtain a scandium product, comprising the steps of:

[0032] The alkali solution and the scandium-rich eluent are mixed and solid-liquid separated, and then the precipitate obtained by the solid-liquid separation is dissolved to obtain a scandium-rich solution;

[0033] The organic acid solution and the scandium-rich solution are mixed to precipitate the scandium in the scandium-rich solution to obtain a scandium product.

[0034] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0035] The embodiment of the present application provides a method for extracting scandium by combined extraction, adsorption and separation. The method first reduces a scandium-containing solution so that the iron ions in the scandium-containing solution are converted into ferrous ions. Then, the pretreatment solution is first subjected to a first resin adsorption using a phosphorus-containing impregnating resin. The phosphorus-containing impregnating resin includes an acidic cation adsorption resin and an extractant impregnated in the acidic cation adsorption resin. The specific adsorption of scandium by the extractant of the phosphorus-containing impregnating resin is utilized to increase the speed at which the acidic cation adsorption resin adsorbs scandium in the pretreatment solution, thereby reducing the probability of the acidic cation adsorption resin adsorbing ferrous ions, thereby enabling the phosphorus-containing impregnating resin to quickly and selectively adsorb the pretreatment solution. Scandium is adsorbed without adsorbing ferrous ions, so as to preliminarily improve the recovery rate of scandium in the scandium-containing solution; in addition, a chelating resin containing an aminocarboxyl group is used for a second resin adsorption, and the amino and carboxyl groups on the chelating resin containing an aminocarboxyl group can accurately identify and capture a large amount of scandium in the pretreatment solution without combining with ferrous ions, so as to selectively adsorb a large amount of scandium in the pretreatment solution without adsorbing ferrous ions, thereby improving the recovery rate of scandium in the scandium-containing solution; therefore, the method reduces the scandium-containing solution with a reducing agent, and then uses the phosphorus-containing impregnated resin and the chelating resin containing an aminocarboxyl group in series, so as to maximize the recovery of scandium in the scandium-containing solution and improve the recovery rate of scandium in the scandium-containing solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which are incorporated in and constitute a part of this 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0038] Figure 1 A schematic flow chart of a method for combined extraction, adsorption and separation of scandium provided in an embodiment of the present application;

[0039] Figure 2 A detailed schematic diagram of a combined extraction and adsorption separation method for extracting scandium provided in an embodiment of the present application;

[0040] Figure 3 A schematic diagram of the actual process of a method for extracting scandium by combined extraction and adsorption separation provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0042] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within 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., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range; in addition, whenever a numerical range is indicated in this document, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0043] In this document, the terms including "including" and "including" mean "including but not limited to". Relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone; where A and B can be singular or plural. "At least one" means one or more, and "plurality" means two or more; "at least one", "at least one of the following" or similar expressions, refers to any combination of these items, including any combination of single or plural items; for example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. "Parts" such as parts by weight and parts by mass indicate the proportional relationship between the components. In the proportional relationship involved in this article, the parameters that need to be described by proportion should be understood as the first term of the proportional formula in the order of description, and the proportional numbers should be understood as the second term of the proportional formula. For example, if the mass ratio of substance A, substance B and substance C is 1:2:3, then substance A, substance B and substance C should correspond to the proportional numbers in the proportional formula in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

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

[0045] Figure 1 A schematic flow chart of a method for extracting scandium by combined extraction and adsorption separation provided in an embodiment of the present application is shown by way of example;

[0046] like Figure 1 As shown, the embodiment of the present application provides a method for extracting scandium by combined extraction, adsorption and separation, which is used to extract scandium from a scandium-containing solution containing iron ions. The method comprises:

[0047] S1. using a reducing agent to carry out a reduction reaction of the scandium-containing solution so that the iron ions are reduced to ferrous ions to obtain a pre-treated solution containing scandium and ferrous ions;

[0048] S2. using a phosphorus-containing impregnating resin to subject the pretreatment solution to a first resin adsorption to selectively adsorb scandium in the pretreatment solution and remove a small portion of ferrous ions in the pretreatment solution to obtain a scandium-rich first adsorption resin and a scandium-removed slurry containing less scandium; wherein the phosphorus-containing impregnating resin comprises an acidic cationic adsorption resin and a phosphorus-containing extractant impregnated in the acidic cationic adsorption resin;

[0049] S3. using a chelating resin containing an aminocarboxyl group, the scandium-depleted slurry is subjected to a second resin adsorption to selectively adsorb scandium from the scandium-depleted slurry containing less scandium, and remove most of the ferrous ions from the pretreatment solution to obtain a scandium-rich second adsorption resin;

[0050] S4. respectively removing impurities and desorbing the first adsorption resin and the second adsorption resin to obtain a scandium-rich eluent; and

[0051] S5. Purifying the scandium-rich eluate to obtain a scandium product.

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

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

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

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

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

[0057] It should be noted that the eluent in the desorption process can elute the phosphorus-containing impregnated resin or the aminocarboxyl-containing chelating resin from bottom to top to fully elute the scandium adsorbed in the phosphorus-containing impregnated resin or the aminocarboxyl-containing chelating resin, thereby finally obtaining a scandium-rich eluent.

[0058] It should be noted that the first adsorption resin and the second adsorption resin after desorption can be regenerated respectively and can be recycled.

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

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

[0061] The temperature of the second resin adsorption is 50°C to 80°C, and the time of the second resin adsorption is 20h to 50h;

[0062] In these embodiments, the temperature of the first resin adsorption can be 20°C to 35°C, and the time of the first resin adsorption can be 5h to 20h, so that the phosphorus-containing impregnating resin has sufficient temperature and sufficient time to adsorb the scandium in the pretreatment solution to ultimately obtain the first adsorption resin; in addition, the temperature of the second resin adsorption can be 50°C to 80°C, and the time of the second resin adsorption can be 20h to 50h, so that the chelating resin containing aminocarboxyl groups has sufficient temperature and sufficient time to adsorb the scandium in the scandium-free slurry containing less scandium to ultimately obtain the second adsorption resin.

[0063] The temperature at which the first resin is adsorbed may be 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C or 35°C.

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

[0065] The temperature at which the second resin is adsorbed may be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C.

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

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

[0068] In these embodiments, the first resin adsorption and the second resin adsorption can be respectively carried out in a countercurrent contact manner, and the flow rate of the countercurrent contact is ≥0.5mL / min. The countercurrent contact manner can promote the pretreatment solution to fully contact with the phosphorus-containing impregnating resin and the aminocarboxyl-containing chelating resin, so that the scandium in the scandium-containing solution can effectively enter the phosphorus-containing impregnating resin and the aminocarboxyl-containing chelating resin, thereby facilitating subsequent desorption to obtain a scandium product with sufficient purity and recovery rate.

[0069] In some optional embodiments, the chelating resin containing aminocarboxyl groups includes a weakly acidic macroporous cation exchange resin containing aminomethylphosphonic acid functional groups.

[0070] In these embodiments, the chelating resin containing aminocarboxyl groups may include a weakly acidic macroporous cation exchange resin containing an aminomethylphosphonic acid functional group. The weakly acidic macroporous cation exchange resin containing an aminomethylphosphonic acid functional group can accurately identify and capture scandium in a complex scandium-less descandium slurry containing multiple metal ions, and is not interfered by other non-target ions, so as to selectively adsorb scandium of the pretreatment solution in large quantities without adsorbing ferrous ions, thereby improving the recovery rate of scandium in the scandium-containing solution.

[0071] It should be noted that the aminocarboxyl-containing chelating resin can be chelating resin TP260, and this chelating resin TP260 can selectively remove alkaline earth metal cations, and the independent dispersed particles of this chelating resin TP260 also have outstanding mechanical and osmotic stability in addition, which makes this chelating resin TP260 compared with the ion exchange resin of non-uniform dispersion, has more excellent kinetic characteristics, thereby makes this chelating resin TP260 have higher working exchange capacity. Based on the good chemical stability and mechanical strength of this chelating resin TP260 in addition, it is possible to use in the acid, alkali or saline solution of high concentration and not degraded or lose efficacy. In addition this chelating resin TP260 also has higher regeneration ability, carries out regeneration treatment through suitable regenerant, can recover its adsorption properties and realize recycling.

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

[0073] Figure 3 The actual process diagram of a combined extraction adsorption separation method for extracting scandium provided in an embodiment of the present application is exemplarily shown;

[0074] In some optional embodiments, such as Figure 2 and Figure 3 As shown, the preparation method of the phosphorus-containing impregnating resin comprises:

[0075] S101. washing and removing impurities from the acidic cation adsorption resin, and then drying the washed and removed impurities acidic cation adsorption resin to obtain a pretreated acidic cation adsorption resin;

[0076] S102. The phosphorus-containing extractant and the pretreated acidic cation adsorption resin are vibrated and mixed so that the phosphorus-containing extractant is infiltrated into the pretreated acidic cation adsorption resin to obtain a crude phosphorus-containing impregnated resin;

[0077] S103. The crude phosphorus-containing impregnating resin is subjected to negative pressure distillation to obtain a phosphorus-containing impregnating resin;

[0078] In these embodiments, the acidic cation adsorption resin is first pretreated to remove impurities on its surface, and then the phosphorus-containing extractant and the pretreated acidic cation adsorption resin are oscillated and mixed to allow the phosphorus-containing extractant to penetrate into the pretreated acidic cation adsorption resin, thereby obtaining a phosphorus-containing impregnated resin soaked with the extractant, and finally the diluent component of the extractant is removed by negative pressure distillation to ultimately obtain a pure phosphorus-containing impregnated resin.

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

[0080] It should be noted that the oscillation mixing time can be 12 hours.

[0081] It should be noted that the adsorption amount of the phosphorus-containing extractant in the pretreatment of the acidic cation adsorption resin is related to the type of the acidic cation adsorption resin, so the phosphorus-containing extractant needs to be in excess relative to the acidic cation adsorption resin.

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

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

[0084] In these embodiments, the acidic cation adsorption resin may include: at least one of phenyl strong acid resin, cross-linked polystyrene-based macroporous resin and TVEX resin, and the phosphorus-containing extractant may include tributyl phosphate and a phosphorus-containing component, and the phosphorus-containing component may include: at least one of bis(2,4,4-trimethylpentyl)phosphonic acid, diisooctyl methylphosphonate, and di(2-ethylhexyl)phosphate, so that the acidic cation adsorption resin adsorbs a sufficient amount of the phosphorus-containing extractant. A sufficient amount of the phosphorus-containing extractant can increase the speed at which the acidic cation adsorption resin adsorbs scandium in the pretreatment solution to reduce the probability of the acidic cation adsorption resin adsorbing ferrous ions, thereby prompting the phosphorus-containing impregnated resin to quickly and selectively adsorb scandium in the pretreatment solution without adsorbing ferrous ions, so as 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 phenyl strong acid resin Dowex 50-X8, and the pore size of the phenyl strong acid resin Dowex 50-X8 can be 100 mesh to 200 mesh; the TVEX resin can be TVEX-TOPO resin, TVEX-PHOR, or TVEX-DIOMP.

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

[0087] The reduction reaction time is 30min to 60min;

[0088] In these embodiments, the reducing agent may include sodium sulfite, and the reduction reaction time may be 30 min to 60 min. The iron ions in the scandium-containing solution may be reduced to ferrous ions by sodium sulfite, and the sulfite ions are converted into sulfate ions. The converted sulfate ions will also react with the calcium ions in the scandium-containing solution during a sufficiently long reduction reaction stage to generate calcium sulfate precipitates. The calcium sulfate component may be separated from the scandium-containing solution by solid-liquid separation, thereby achieving the reduction of iron ions and the removal of calcium ions.

[0089] In some optional embodiments, the first adsorption resin and the second adsorption resin are subjected to impurity removal and desorption respectively to obtain a scandium-rich eluent, comprising the steps of:

[0090] S401. Using a washing liquid, the first adsorption resin and the second adsorption resin are respectively washed and impurity-removed to obtain a first impurity-removing resin and a second impurity-removing resin;

[0091] S402. Pre-desorbing the first impurity-removing resin and the second impurity-removing resin using a dilute ammonia solution to obtain a first pre-desorption resin and a second pre-desorption resin;

[0092] S403. Using an eluent, the first pre-desorption resin and the second pre-desorption resin are desorbed and combined to obtain a scandium-rich eluent;

[0093] In these embodiments, the first adsorption resin and the second adsorption resin are respectively eluted and decontaminated with an eluent to remove impurities from the first adsorption resin and the second adsorption resin to obtain a first decontaminated resin and a second decontaminated resin; then, a dilute ammonia solution is used for pre-desorption, and the alkaline molecules of the dilute ammonia solution preliminarily occupy the permeation channels of the first decontaminated resin and the second decontaminated resin, thereby reducing the risk of subsequent eluent penetrating into the first decontaminated resin and the second decontaminated resin, avoiding the fluidization of the phosphorus-containing impregnated resin or the aminocarboxyl-containing chelating resin, thereby extending the service life of these resins; finally, the eluent is used for desorption and merging, so that the scandium of the first pre-desorption resin and the second pre-desorption resin can be effectively eluted without damaging the resin body.

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

[0095] The temperature of the elution and impurity removal is 80°C to 95°C; and / or

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

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

[0098] In these embodiments, a sulfuric acid solution with ammonium chloride added is used for shower washing and impurity removal. Ammonium chloride can change the oxidation potential of the eluent, thereby promoting the removal of impurities. In addition, the temperature of the elution and impurity removal can be 80°C to 95°C, which can reduce the dissolution of scandium in the first adsorption resin and the second adsorption resin in the eluent during the elution and impurity removal stage, thereby reducing the loss of scandium in the elution and impurity removal stage. In addition, the flow rate of the eluent is ≥2mL / cm 2 The faster eluent flow rate can effectively dissolve the impurities adsorbed by the first adsorption resin and the second adsorption resin into the eluent, so as to effectively remove the impurities of 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 first adsorption resin and the second adsorption resin into the eluent, so as to remove scandium from the first adsorption resin and the second adsorption resin.

[0099] The temperature of the elution and impurity removal 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 when the temperature of eluting and impurity removal is less than 80°C, scandium will dissolve into the eluent, causing the scandium of the first adsorption resin and the second adsorption resin to dissolve into the eluent, resulting in the loss of scandium; when the temperature of eluting and impurity removal is greater than 95°C, 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 process of purifying the scandium-rich eluate to obtain a scandium product comprises the steps of:

[0102] S501. The alkali solution and the scandium-rich eluent are mixed and solid-liquid separated, and then the precipitate obtained by the solid-liquid separation is dissolved to obtain a scandium-rich solution;

[0103] S502. The organic acid solution and the scandium-rich solution are mixed to form a precipitate of scandium in the scandium-rich solution to obtain a scandium product;

[0104] In these embodiments, by mixing an alkaline solution and a scandium-rich eluent and performing solid-liquid separation, the scandium in the scandium-rich eluent is converted into a precipitate using an alkaline solution, and then the precipitate is dissolved to obtain a scandium-rich solution; then, the scandium in the scandium-rich solution is separated from the scandium-rich solution in the form of a precipitate using an organic acid to obtain a scandium product.

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

[0106] It should be noted that the organic acid solution may be an oxalic acid solution or a tartaric acid solution; when the organic acid solution is an oxalic acid solution, the scandium product obtained may be scandium oxalate.

[0107] It should be noted that the solvent of the oxalic acid solution and the tartaric acid solution can be ethanol in an amount equal to that of a solute such as oxalic acid or tartaric acid.

[0108] The present application is further described below in conjunction with specific examples. The experimental methods in the following examples where specific conditions are not specified are usually measured in accordance with national standards / industry standards; if there are no corresponding national standards / industry standards, they are measured in accordance with common international standards, conventional conditions or conditions recommended by the manufacturer.

[0109] Example 1

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

[0111] A method for extracting scandium by combined extraction, adsorption and separation, for extracting scandium from a scandium-containing solution containing iron ions, comprising:

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

[0113] The acidic cation adsorption resin is reflux-washed with anhydrous ethanol for about 5 hours to remove impurities such as porogens, catalysts, and reaction solvents contained therein, and then the acidic cation adsorption resin is washed with distilled water until it is neutral, and the above steps are repeated 3 times; after filtering out the acidic cation adsorption resin, the temperature is controlled at 50°C to 60°C in a drying oven for drying to constant weight to obtain a pretreated acidic cation adsorption resin;

[0114] S102. 100 g of the acidic cation adsorption resin was placed in a conical flask, and 500 mL of the fully dissolved extractant was added. The flask was plugged with a rubber stopper and oscillated in an oscillator for 12 h to allow the phosphorus-containing extractant to infiltrate the pretreated acidic cation adsorption resin to obtain a crude phosphorus-impregnated resin;

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

[0116] S1. Using 0.2 g / L of a reducing agent, the scandium-containing solution is subjected to a reduction reaction to reduce iron ions to ferrous ions to obtain a pretreated solution;

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

[0118] S3. using a chelating resin containing an aminocarboxyl group, the scandium-free slurry containing less scandium is subjected to a second resin adsorption to selectively adsorb scandium from the scandium-free slurry containing less scandium, and remove most of the ferrous ions of the pretreatment solution to obtain a second adsorption resin and a scandium-free scandium-free slurry;

[0119] S401. The first adsorption resin and the second adsorption resin are respectively eluted and decontaminated with sulfuric acid eluent containing ammonium chloride (mass concentration 49 g / L), and then the eluent is degassed after slowly heating, and then the first adsorption resin and the second adsorption resin are respectively eluted with distilled water to obtain a first impurity-removing resin and a second impurity-removing resin;

[0120] S402. The first impurity-removing resin and the second impurity-removing resin are pre-desorbed using aqueous ammonia at a mass concentration of 50 g / L, and the flow rate of the aqueous ammonia is controlled to be 1 BV / h to obtain a first pre-desorption resin and a second pre-desorption resin;

[0121] S403. Using a sodium carbonate solution having a mass concentration of 180 g / L as an eluent, the first pre-desorption resin and the second pre-desorption resin were desorbed and combined, and the flow rate of the eluent was controlled to be 1 BV / h to obtain a scandium-rich eluent;

[0122] S501. The alkali solution and the scandium-rich eluent are fully mixed, the volume of the alkali solution added is 1 / 5 of the volume of the scandium-rich eluent, the mass concentration of the alkali solution added is 3.5 mol / L, and then the solid-liquid separation is carried out, and the precipitate obtained by the solid-liquid separation is dissolved to obtain a scandium-rich solution;

[0123] S502. Mix the oxalic acid solution and the scandium-rich solution to precipitate the scandium in the scandium-rich solution to obtain a scandium oxalate product. The temperature of the first resin adsorption is 25° C., and the first resin adsorption time is 10 hours;

[0124] The temperature for the second resin adsorption is 80° C., and the time for the second resin adsorption is 35 h.

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

[0126] Chelating resins containing aminocarboxyl groups include weakly acidic macroporous cation exchange resins containing aminomethylphosphonic acid functional groups.

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

[0128] The phosphorus-containing extractant comprises tributyl phosphate and a phosphorus-containing component, wherein 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] Reducing agents include sodium sulfite;

[0130] The reduction reaction time is 30 min.

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

[0132] The temperature for elution and impurity removal is 80℃~95℃;

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

[0134] The desorption temperature was 80°C.

[0135] Example 2

[0136] Based on the contents disclosed in Example 1, the following modifications are further made:

[0137] Adjust the pH of the scandium solution to 2.

[0138] Example 3

[0139] Based on the contents disclosed in Example 1, the following modifications are further made:

[0140] Red mud acid leaching solution was used as the scandium-containing solution, and the mass concentration of scandium was 0.0054 g / L.

[0141] Example 4

[0142] Based on the contents disclosed in Example 1, the following modifications are further made:

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

[0144] The temperature for the second resin adsorption is 50° C., and the time for the second resin adsorption is 30 h.

[0145] Example 5

[0146] Based on the contents disclosed in Example 1, the following modifications are further made:

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

[0148] The temperature for the second resin adsorption was 65° C., and the time for the second resin adsorption was 20 h.

[0149] Example 6

[0150] Based on the contents disclosed in Example 1, the following modifications are further made:

[0151] Use tartaric acid instead of oxalic acid.

[0152] Comparative Example 1

[0153] Based on the contents disclosed in Example 1, the following modifications are further made:

[0154] No phosphorus-containing impregnated resin was used, and chelating resin was used for both resin adsorptions.

[0155] Comparative Example 2

[0156] Based on the contents disclosed in Example 1, the following modifications are further made:

[0157] No chelating resin was used, and phosphorus-impregnated resin was used in both resin adsorptions.

[0158] Comparative Example 3

[0159] Based on the contents disclosed in Example 1, the following modifications are further made:

[0160] Adjust the pH of the scandium solution to 1.

[0161] Comparative Example 4

[0162] Based on the contents disclosed in Example 1, the following modifications are further made:

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

[0164] The temperature for the second resin adsorption is 40° C., and the time for the second resin adsorption is 60 h.

[0165] Comparative Example 5

[0166] Based on the contents disclosed in Example 1, the following modifications are further made:

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

[0168] The temperature for the second resin adsorption was 90° C., and the time for the second resin adsorption was 10 h.

[0169] Related experiments and effect data:

[0170] The scandium recovery rates of the scandium-rich eluents and the scandium recovery rates of the scandium products in the embodiments and comparative examples were statistically analyzed and the results are shown in Table 1.

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

[0172]

[0173]

[0174] As can be seen from Table 1, an embodiment of the present application provides a method for combined extraction, adsorption and separation of scandium. This method can maximize the recovery of scandium from the scandium-containing solution and increase the recovery rate of scandium from the scandium-containing solution to more than 90% by reducing the scandium-containing solution and then using a phosphorus-containing impregnated resin and an aminocarboxyl-containing chelating resin in series. In addition, this method can recover more than 90% of scandium from a scandium-rich eluate and generate a scandium product.

[0175] In addition, an embodiment of the present application provides a method for extracting scandium by combined extraction, adsorption and separation, which uses a phosphorus-containing extractant that does not contain organic solvents in combination with an acidic cationic resin to achieve accurate extraction of scandium from a scandium-containing solution, which can greatly reduce the use of organic solvents, so that the method does not require an organic solvent to dilute the liquid extractant, so the method does not have a phase separation problem, and the equipment required for the method is simple and the factory occupies a smaller area, which makes the production cost of the method lower.

[0176] In addition, an embodiment of the present application provides a method for extracting scandium by combined extraction, adsorption and separation. Based on this method, a large amount of scandium can be fully recovered from the scandium-containing solution, and trace impurities in the scandium-containing solution can be efficiently removed. The purity of scandium can be ensured while maximizing the recovery of scandium, which provides an efficient and reliable solution to the problem of metal ion contamination in industrial processes.

[0177] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. It will be apparent to those skilled in the art that various modifications to these embodiments are possible, 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 for by the present application.

Claims

1. A method for extracting scandium by combined extraction, adsorption and separation, for extracting scandium from a scandium-containing solution containing iron ions, the method comprising: The scandium-containing solution is subjected to a reduction reaction to reduce the iron ions to ferrous ions, thereby obtaining a pretreatment solution containing scandium and ferrous ions; Using a phosphorus-containing impregnating resin, subjecting the pretreatment solution to a first resin adsorption to selectively adsorb scandium in the pretreatment solution and remove a small portion of ferrous ions in the pretreatment solution, thereby obtaining a scandium-rich first adsorption resin and a scandium-removed slurry containing less scandium; wherein the phosphorus-containing impregnating resin comprises an acidic cationic adsorption resin and a phosphorus-containing extractant impregnated in the acidic cationic adsorption resin; Using a chelating resin containing aminocarboxyl groups, subjecting the scandium-depleted slurry containing less scandium to second resin adsorption, so as to selectively adsorb the scandium in the scandium-depleted slurry containing less scandium and remove most of the ferrous ions in the pretreatment solution, thereby obtaining a scandium-rich second adsorption resin; Respectively subjecting the first adsorption resin and the second adsorption resin to impurity removal and desorption to obtain a scandium-rich eluent; and The scandium-rich eluate is purified to obtain a scandium product.

2. The method according to claim 1, wherein the temperature of the first resin adsorption is 20°C to 35°C, and the time of the first resin adsorption is 5h to 20h; and / or The temperature for the second resin adsorption is 50° C. to 80° C., and the time for the second resin adsorption is 20 h to 50 h.

3. The method according to claim 1, wherein the first resin adsorption and the second resin adsorption are respectively performed in a countercurrent contact manner, and the flow rate of the countercurrent contact is ≥0.5 mL / min.

4. method according to claim 1, the described chelating resin that contains aminocarboxyl comprises the weakly acidic macroporous cation exchange resin that contains aminomethylphosphoric acid functional group.

5. The method according to claim 1, wherein the preparation method of the phosphorus-containing impregnating resin comprises: The acidic cation adsorption resin is washed and impurity-removed, and then the acidic cation adsorption resin after washing and impurity-removal is dried to obtain a pretreated acidic cation adsorption resin; The phosphorus-containing extractant and the pretreated acidic cation adsorption resin are vibrated and mixed so that the phosphorus-containing extractant is infiltrated into the pretreated acidic cation adsorption resin to obtain a crude phosphorus-containing impregnated resin; The crude phosphorus-containing impregnating resin is subjected to negative pressure distillation to obtain the phosphorus-containing impregnating resin.

6. The method according to claim 1 or 5, wherein the acidic cation adsorption resin comprises at least one of the following: phenyl strong acid resin, cross-linked polystyrene-based macroporous resin and TVEX resin; The phosphorus-containing extractant comprises tributyl phosphate and a phosphorus-containing component, wherein the phosphorus-containing component comprises at least one of the following: bis(2,4,4-trimethylpentyl)phosphonic acid, diisooctyl methylphosphonate, and di(2-ethylhexyl)phosphate.

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

8. The method according to claim 1, wherein the first adsorption resin and the second adsorption resin are subjected to impurity removal and desorption respectively to obtain a scandium-rich eluent; Using a washing liquid to wash and remove impurities from the first adsorption resin and the second adsorption resin, respectively, to obtain a first impurity-removing resin and a second impurity-removing resin; Pre-desorbing the first impurity-removing resin and the second impurity-removing resin using a dilute ammonia solution to obtain a first pre-desorption resin and a second pre-desorption resin; The first pre-desorption resin and the second pre-desorption resin are respectively desorbed and combined using an eluent to obtain a scandium-rich eluent.

9. The method according to claim 8, wherein the eluent comprises a sulfuric acid eluent containing ammonium chloride and / or distilled water; and / or The temperature of the elution and impurity removal is 80°C to 95°C; and / or The flow rate of the eluent is ≥2mL / cm 2 ; and / or The desorption temperature is ≤80°C.

10. The method according to claim 1, wherein the scandium-rich eluate is purified to obtain a scandium product, comprising the steps of: The alkali solution and the scandium-rich eluent are mixed and solid-liquid separated, and then the precipitate obtained by the solid-liquid separation is dissolved to obtain a scandium-rich solution; The organic acid solution and the scandium-rich solution are mixed to precipitate the scandium in the scandium-rich solution to obtain a scandium product.

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