Method for separating scandium from scandium-containing organic phase

Abstract

The invention provides a method for separating scandium from a scandium-containing organic phase. The method comprises the following steps: introducing a first sulfuric acid solution into a second sub-mixing section of a second separation section; the scandium-containing organic phase is introduced into a fourth sub-mixing section of a fourth separation section, liquid-liquid separation is performed in a fourth sub-clarifying section to obtain fourth raffinate, the fourth raffinate is introduced into a third separation section, liquid-liquid separation is performed in a third sub-clarifying section, and then third raffinate is discharged; a solution containing second sulfuric acid is introduced into the ith sub-mixing section of the ith separation section; a hydrochloric acid solution is introduced into the jth sub-mixing section of the jth separation section, scandium in the scandium-containing organic phase is washed and enters jth raffinate, and scandium is recovered; the sodium carbonate solution is introduced into the nth sub-mixing section of the nth separation section; wherein i and j are respectively and independently integers from 4 to n, i is smaller than j, and n is the total separation section number. According to the invention, the frequency and severity of miscible phase conditions are reduced, and the stability of the separation system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgy, and in particular to a method for separating scandium from a scandium-containing organic phase. Background Art

[0002] During the extraction of cobalt and nickel, the scandium in the raw material will continue to accumulate in the organic matter and eventually cause organic poisoning, resulting in a sharp drop in organic extraction capacity and seriously affecting production.

[0003] Currently, production lines are studying the separation and extraction of scandium from laterite nickel ore. For example, CN103468972A discloses a method for comprehensively recovering scandium and nickel-cobalt from laterite nickel ore. The method includes: performing a first leaching treatment on the laterite nickel ore with sulfuric acid to obtain a laterite nickel ore leachate; performing a nickel-cobalt precipitation treatment on the laterite nickel ore leachate to obtain nickel-cobalt hydroxide precipitates; performing a second leaching treatment on the nickel-cobalt hydroxide precipitate with sulfuric acid to obtain a nickel-cobalt leachate; performing a scandium extraction treatment on the nickel-cobalt leachate with an organic extractant to obtain a nickel-cobalt solution and an organic phase containing scandium; recovering nickel and cobalt from the nickel-cobalt solution; and recovering scandium from the organic phase containing scandium. However, this method suffers from severe phase mixing and requires frequent downtime.

[0004] CN118854094A discloses a method for separating scandium and yttrium from crude nickel cobalt hydroxide. The method comprises the following steps: adding water to the crude nickel cobalt hydroxide, adding acid to carry out a dissolution reaction, adding crude nickel cobalt hydroxide to adjust the pH, and performing solid-liquid separation to obtain an acid solution and an acid slag; removing silicon, performing precision filtration, and performing solvent extraction to obtain a loaded organic phase and a raffinate; washing the loaded organic phase to obtain an organic phase I; sequentially performing preliminary yttrium stripping, deep yttrium stripping, and scandium stripping on the loaded organic phase with a mixed solution of hydrochloric acid and oxalic acid of varying concentrations from low to high to obtain a scandium oxalate precipitate, which is then washed, dried, and calcined to obtain scandium oxide; and precipitating yttrium, washing, and calcining the third washing solution obtained from the yttrium stripping to obtain yttrium oxide. However, the method is complex, and the raw materials differ from those of laterite nickel ore leaching, making it difficult to draw on.

[0005] Therefore, it is necessary to separate the scandium-containing raw materials in advance before entering the cobalt-nickel extraction system to reduce the Sc content in the raw materials and reduce subsequent organic poisoning. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for separating scandium from a scandium-containing organic phase, which can significantly reduce the frequency and severity of mixed phases and extend the startup time.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for separating scandium from a scandium-containing organic phase, characterized in that the method includes n separation sections, wherein each separation section includes a sub-mixing section and a sub-clarification section, wherein the stirred mixed liquid obtained in the sub-mixing section enters the sub-clarification section for liquid-liquid phase separation to obtain an extracted organic phase and a raffinate of the corresponding separation section, wherein the extracted organic phase enters the sub-mixing section of the next separation section.

[0009] The process of running the method includes:

[0010] The first sulfuric acid solution is introduced into the second sub-mixing section of the second separation section, and the first raffinate is discharged from the first separation section.

[0011] The scandium-containing organic phase is passed into the 4th sub-mixing section of the 4th separation section, and the 4th raffinate is obtained after liquid-liquid separation in the 4th sub-clarification section. The 4th raffinate is passed into the 3rd separation section and the 3rd raffinate is discharged after liquid-liquid separation in the 3rd sub-clarification section.

[0012] The second sulfuric acid solution is passed into the i-th sub-mixing section of the i-th separation section, and the i-th raffinate obtained enters the sub-mixing section of the previous separation section, and the process is continued step by step until the fifth raffinate is obtained, and the fifth raffinate is discharged.

[0013] The hydrochloric acid solution is passed into the jth sub-mixing section of the jth separation section to wash the scandium in the scandium-containing organic phase into the jth raffinate to recover the scandium. The obtained jth raffinate is passed into the sub-mixing section of the previous separation section, and the process is carried out step by step until the i+1th raffinate is obtained, and the i+1th raffinate is discharged.

[0014] The sodium carbonate solution is passed into the nth sub-mixing section of the nth separation section, and the obtained nth raffinate enters the sub-mixing section of the previous separation section, and the process is continued step by step until the j+1th raffinate is obtained, and the j+1th raffinate is discharged.

[0015] Wherein, i and j are each independently an integer from 4 to n, i is smaller than j, and n is the total number of separation stages.

[0016] The present invention consumes the sodium carbonate introduced by the nth separation section by passing the first sulfuric acid solution into the second separation section, effectively preventing the sodium carbonate from entering the third separation section, and significantly reducing the risk of mixed phases; further, the present invention improves the process of passing the scandium-containing organic phase into the fourth separation section, where most of the scandium and a small amount of cobalt and nickel are extracted into the organic phase, thereby achieving scandium extraction; in the i-th separation section, the scandium-containing organic phase is reversely washed with a second sulfuric acid solution, and the cobalt, nickel and scandium entrained in the organic phase are washed into the i-th aqueous phase; in the j-th separation section, the hydrochloric acid solution can wash the scandium from the organic phase into the j-th raffinate, and continuously enrich it to achieve the recovery of the scandium chloride solution, and recover scandium from the i+1-th raffinate; and the sodium carbonate solution is passed into the n-th separation section to wash the chloride ions introduced in the j-th separation section, thereby preventing the chloride ions from being entrained into the third separation section through the organic phase.

[0017] The improved process can significantly improve the problem of frequent phase mixing in the existing scandium extraction line process, which leads to short continuous startup time.

[0018] Preferably, the concentration of the first sulfuric acid solution is 0.5-1.5 mol / L.

[0019] Preferably, the flow ratio of the first sulfuric acid solution to the scandium-containing organic phase is 0.03-0.05:1.

[0020] Preferably, the Sc concentration in the third raffinate is less than 5 mg / L.

[0021] Preferably, the sulfuric acid concentration of the second sulfuric acid-containing solution is 0.5 to 1.5 mol / L.

[0022] Preferably, the flow ratio of the second sulfuric acid solution to the scandium-containing organic phase is 0.008-0.012:1.

[0023] Preferably, when the scandium-containing organic phase contains titanium, the second sulfuric acid-containing solution is mixed with H2O2.

[0024] Preferably, the mass concentration of H2O2 in the second sulfuric acid solution is 25-35 wt%.

[0025] Preferably, the concentration of the hydrochloric acid solution is 3 to 5 mol / L.

[0026] Preferably, the flow ratio of the hydrochloric acid solution to the scandium-containing organic phase is 0.03-0.05:1.

[0027] Preferably, the mass concentration of scandium chloride in the (i+1) raffinate is 10-20 g / L.

[0028] Preferably, the concentration of the sodium carbonate solution is 0.2 to 1.5 mol / L.

[0029] Preferably, the flow ratio of the sodium carbonate solution to the scandium-containing organic phase is 0.05-0.15:1.

[0030] Preferably, during the operation of the method, the pH of the j+1th raffinate is monitored to be within a first value.

[0031] Preferably, the first value ranges from 5.8 to 6.5.

[0032] Preferably, the value range of i is 7-9.

[0033] Preferably, the value range of j is 12-15.

[0034] Preferably, the value range of n is 18-22.

[0035] Preferably, the nickel content in the scandium-containing organic phase is 30-50 g / L.

[0036] Preferably, the cobalt content in the scandium-containing organic phase is 3000-7000 mg / L.

[0037] Preferably, the scandium content in the scandium-containing organic phase is 600-800 mg / L.

[0038] Preferably, the scandium-containing organic phase further comprises iron and / or titanium.

[0039] Preferably, the iron content in the scandium-containing organic phase is 0.2-0.5 g / L.

[0040] Preferably, the titanium content in the scandium-containing organic phase is 500-1000 mg / L.

[0041] As a preferred technical solution of the present invention, the method includes n separation sections, wherein each separation section includes a sub-mixing section and a sub-clarification section, wherein the stirred mixed liquid obtained in the sub-mixing section enters the sub-clarification section for liquid-liquid phase separation to obtain an extracted organic phase and a raffinate of the corresponding separation section, wherein the extracted organic phase enters the sub-mixing section of the next separation section;

[0042] The process of running the method includes:

[0043] A first sulfuric acid solution with a concentration of 0.5 to 1.5 mol / L enters the second separation section, and a first raffinate is discharged from the first separation section; wherein the flow ratio of the first sulfuric acid solution to the scandium-containing organic phase is 0.03 to 0.05:1;

[0044] The scandium-containing organic phase is passed into the fourth separation section, and the obtained fourth raffinate flows out of the third separation section and undergoes liquid-liquid separation in the fourth sub-clarification section to obtain a fourth raffinate. The fourth raffinate is passed into the third separation section and undergoes liquid-liquid separation in the third sub-clarification section, and then the third raffinate is discharged;

[0045] A second sulfuric acid solution having a sulfuric acid concentration of 0.5 to 1.5 mol / L is passed into the i-th separation section, with a flow ratio of the second sulfuric acid solution to the scandium-containing organic phase being 0.008 to 0.012:1. The i-th raffinate obtained enters the sub-mixing section of the previous separation section, and is continuously mixed until a fifth raffinate is obtained, which is then discharged.

[0046] Wherein, when the scandium-containing organic phase contains titanium, the second sulfuric acid solution is mixed with H2O2, and the mass concentration of H2O2 in the second sulfuric acid solution is 25-35wt%;

[0047] A hydrochloric acid solution with a concentration of 3 to 5 mol / L is passed into the jth separation section to wash the scandium in the scandium-containing organic phase into the jth raffinate. The obtained jth raffinate enters the sub-mixing section of the previous separation section, and the process is continued step by step until the i+1th raffinate is obtained. The i+1th raffinate is discharged, and the mass concentration of scandium chloride in the i+1th raffinate is 10 to 20 g / L. The flow ratio of the hydrochloric acid solution to the scandium-containing organic phase is 0.03 to 0.05:1.

[0048] A sodium carbonate solution with a concentration of 0.2 to 1.5 mol / L is passed into the nth separation section, and the obtained nth raffinate enters the sub-mixing section of the previous separation section, and the process is continued step by step until the j+1th raffinate is obtained, and the j+1th raffinate is discharged; and the pH of the j+1th raffinate is monitored to be within a range of 5.8 to 6.5; wherein the flow ratio of the sodium carbonate solution to the scandium-containing organic phase is 0.05 to 0.15:1;

[0049] Among them, the value range of i is 7 to 9, the value range of j is 12 to 15, the value range of n is 18 to 22, and n is the total number of separation stages.

[0050] Compared with the prior art, the present invention has at least the following beneficial effects:

[0051] The method for separating scandium from a scandium-containing organic phase provided by the present invention can significantly reduce phase mixing by using a first sulfuric acid solution to remove sodium carbonate in the front-stage process of introducing the scandium-containing organic phase, and the introduction of a sodium carbonate solution in the nth separation stage can effectively reduce the entrainment of chloride ions entering the subsequent process, thereby significantly reducing phase mixing and allowing long-term continuous operation, extending the continuous operation time of 3 hours in the traditional process to more than 2 days. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1The present invention provides a schematic flow diagram of a method for separating scandium from a scandium-containing organic phase. DETAILED DESCRIPTION

[0053] For the convenience of understanding the present invention, the present invention is given below with examples. It should be understood by those skilled in the art that the examples are only for the purpose of helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] It should be understood that, in the description of the present invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0055] Currently, the scandium extraction method used on the production line includes the following steps:

[0056] The Sc-containing raw material enters the second separation section, and the raffinate is discharged from the first separation section. Most of the scandium and a small amount of cobalt and nickel will be extracted into the organic phase.

[0057] The dilute hydrochloric acid enters the third separation stage, thoroughly washing the scandium from the organic phase into the aqueous phase, and continuously enriching it to obtain a scandium chloride solution.

[0058] Dilute sulfuric acid and hydrogen peroxide enter the 8th separation section. When the scandium-containing raw material contains Ti, hydrogen peroxide is added to the dilute sulfuric acid to wash the cobalt, nickel and titanium in the organic central band into the aqueous phase and discharge from the 4th separation section.

[0059] The dilute sulfuric acid solution enters the 9th separation section, and the chloride ion concentration in the 1st separation section is monitored to ensure that the chloride ions in the organic matter have been washed away.

[0060] As a specific embodiment of the present invention, a method for separating scandium from a scandium-containing organic phase is provided, such as Figure 1 As shown, the method includes n separation sections, wherein each separation section includes a sub-mixing section and a sub-clarifying section, wherein the stirred mixed liquid obtained in the sub-mixing section enters the sub-clarifying section for liquid-liquid phase separation to obtain an extracted organic phase and a raffinate of the corresponding separation section, wherein the extracted organic phase enters the sub-mixing section of the next separation section.

[0061] The process of running the method includes:

[0062] The first sulfuric acid solution is passed into the second sub-mixing section of the second separation section, and the first raffinate is discharged from the first separation section;

[0063] The scandium-containing organic phase is passed into the fourth sub-mixing section of the fourth separation section, and undergoes liquid-liquid separation in the fourth sub-clarification section to obtain a fourth raffinate. The fourth raffinate is passed into the third separation section and undergoes liquid-liquid separation in the third sub-clarification section, and then a third raffinate is discharged.

[0064] The second sulfuric acid solution is passed into the i-th sub-mixing section of the i-th separation section, and the i-th raffinate obtained is passed into the sub-mixing section of the previous separation section, and the process is continued step by step until the fifth raffinate is obtained, and the fifth raffinate is discharged;

[0065] The hydrochloric acid solution is passed into the jth sub-mixing section of the jth separation section to wash the scandium in the scandium-containing organic phase into the jth raffinate. The obtained jth raffinate is passed into the sub-mixing section of the previous separation section, and the process is continued step by step until the i+1th raffinate is obtained, and the i+1th raffinate is discharged.

[0066] The sodium carbonate solution is passed into the nth sub-mixing section of the nth separation section, and the obtained nth raffinate enters the sub-mixing section of the previous separation section, and the process is continued step by step until the j+1th raffinate is obtained, and the j+1th raffinate is discharged.

[0067] Wherein, i and j are each independently an integer from 4 to n, i is smaller than j, and n is the total number of separation stages.

[0068] The present invention consumes the sodium carbonate introduced by the nth separation section by passing the first sulfuric acid solution into the second separation section, effectively preventing the sodium carbonate from entering the third separation section, and significantly reducing the risk of mixed phases; further, the present invention improves the process of passing the scandium-containing organic phase into the fourth separation section, where most of the scandium and a small amount of cobalt and nickel are extracted into the organic phase, thereby achieving scandium extraction; in the i-th separation section, the scandium-containing organic phase is reversely washed with a second sulfuric acid solution, and the cobalt, nickel and scandium entrained in the organic phase are washed into the i-th aqueous phase; in the j-th separation section, the hydrochloric acid solution can thoroughly wash the scandium from the organic phase into the i+1 raffinate, and continuously enrich it to achieve the recovery of the scandium chloride solution; and the sodium carbonate solution is passed into the n-th separation section to wash the chloride ions introduced in the j-th separation section, thereby preventing the chloride ions from being entrained into the third separation section through the organic phase.

[0069] The improved process can significantly improve the problem of frequent phase mixing in the existing scandium extraction line process, which leads to short continuous startup time.

[0070] As an optional specific embodiment, the concentration of the first sulfuric acid solution is 0.5 to 1.5 mol / L, for example, it can be 0.5 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L or 1.5 mol / L, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0071] As an optional specific embodiment, the flow ratio of the first sulfuric acid solution to the scandium-containing organic phase is 0.03 to 0.05:1, for example, it can be 0.03:1, 0.033:1, 0.035:1, 0.037:1, 0.039:1, 0.042:1, 0.044:1, 0.046:1, 0.048:1 or 0.05:1, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0072] As an optional specific embodiment, the Sc concentration in the third raffinate is less than 5 mg / L, for example, it can be 4.9 mg / L, 4.8 mg / L, 4.7 mg / L, 4.5 mg / L, 4.2 mg / L, 4.0 mg / L, 3.8 mg / L, 3.5 mg / L, 3.2 mg / L or 3.0 mg / L, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0073] As an optional specific embodiment, the sulfuric acid concentration of the second sulfuric acid solution is 0.5 to 1.5 mol / L, for example, it can be 0.5 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L or 1.5 mol / L, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0074] As an optional specific embodiment, the flow ratio of the second sulfuric acid solution to the scandium-containing organic phase is 0.008 to 0.012:1, for example, it can be 0.008:1, 0.0085:1, 0.0089:1, 0.0094:1, 0.0098:1, 0.0103:1, 0.0107:1, 0.0112:1, 0.0116:1 or 0.012:1, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0075] As an optional specific implementation, when the scandium-containing organic phase contains titanium, the second sulfuric acid solution is mixed with H2O2.

[0076] As an optional specific embodiment, the mass concentration of H2O2 in the second sulfuric acid solution is 25 to 35 wt%, for example, it can be 25 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt% or 35 wt%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0077] As an optional specific embodiment, the concentration of the hydrochloric acid solution is 3 to 5 mol / L, for example, it can be 3 mol / L, 3.3 mol / L, 3.5 mol / L, 3.7 mol / L, 3.9 mol / L, 4.2 mol / L, 4.4 mol / L, 4.6 mol / L, 4.8 mol / L or 5 mol / L, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0078] As an optional specific embodiment, the flow ratio of the hydrochloric acid solution to the scandium-containing organic phase is 0.03 to 0.05:1, for example, it can be 0.03:1, 0.033:1, 0.035:1, 0.037:1, 0.039:1, 0.042:1, 0.044:1, 0.046:1, 0.048:1 or 0.05:1, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0079] As an optional specific embodiment, the mass concentration of scandium chloride in the i+1 raffinate is 10-20 g / L, for example, it can be 10 g / L, 12 g / L, 13 g / L, 14 g / L, 15 g / L, 16 g / L, 17 g / L, 18 g / L, 19 g / L or 20 g / L, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0080] As an optional specific embodiment, the concentration of the sodium carbonate solution is 0.2 to 1.5 mol / L, for example, it can be 0.2 mol / L, 0.4 mol / L, 0.5 mol / L, 0.7 mol / L, 0.8 mol / L, 1 mol / L, 1.1 mol / L, 1.3 mol / L, 1.4 mol / L or 1.5 mol / L, but is not limited to the listed values, and other unlisted values ​​within this range are equally applicable.

[0081] As an optional specific embodiment, the flow ratio of the sodium carbonate solution to the scandium-containing organic phase is 0.05 to 0.15:1, for example, it can be 0.05:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, 0.11:1, 0.12:1, 0.13:1, 0.14:1 or 0.15:1, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0082] As an optional specific embodiment, during the operation of the method, the pH of the j+1th raffinate is monitored to be within a first value.

[0083] As an optional specific implementation, the first numerical value ranges from 5.8 to 6.5, for example, it can be 5.8, 5.9, 6, 6.1, 6.2, 6.3, 6.4 or 6.5, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0084] As an optional specific implementation, the value range of i is 7 to 9, for example, it can be 7, 8 or 9.

[0085] As an optional specific implementation, the value range of j is 12 to 15, for example, it can be 12, 13, 14 or 15.

[0086] As an optional specific implementation, the value range of n is 18 to 22, for example, it can be 18, 19, 20, 21 or 22.

[0087] As an optional embodiment, the solvent of the scandium-containing organic phase includes N1923, n-dodecane, isooctyl alcohol, and an environmentally friendly cleaning agent. The mass ratio of N1923, n-dodecane, isooctyl alcohol, and the environmentally friendly cleaning agent is (1.5-2.5):(0.5-1.5):(5-7):1, preferably 2:1:6:1. The present invention has no special requirements for the environmentally friendly cleaning agent, and it can be selected according to the conventional knowledge of those skilled in the art, for example, it can be YT2426.

[0088] As an optional specific embodiment, the nickel content in the scandium-containing organic phase is 30-50 g / L, for example, it can be 30 g / L, 33 g / L, 35 g / L, 37 g / L, 39 g / L, 42 g / L, 44 g / L, 46 g / L, 48 g / L or 50 g / L, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0089] As an optional specific embodiment, the cobalt content in the scandium-containing organic phase is 3000-7000 mg / L, for example, it can be 3000 mg / L, 3445 mg / L, 3889 mg / L, 4334 mg / L, 4778 mg / L, 5223 mg / L, 5667 mg / L, 6112 mg / L, 6556 mg / L or 7000 mg / L, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0090] As an optional specific embodiment, the scandium content in the scandium-containing organic phase is 600-800 mg / L, for example, it can be 600 mg / L, 623 mg / L, 645 mg / L, 667 mg / L, 689 mg / L, 712 mg / L, 734 mg / L, 756 mg / L, 778 mg / L or 800 mg / L, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0091] As an optional specific embodiment, the scandium-containing organic phase further includes iron and / or titanium.

[0092] As an optional specific embodiment, the iron content in the scandium-containing organic phase is 0.2 to 0.5 g / L, for example, it can be 0.2 g / L, 0.24 g / L, 0.27 g / L, 0.3 g / L, 0.34 g / L, 0.37 g / L, 0.4 g / L, 0.44 g / L, 0.47 g / L or 0.5 g / L, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0093] As an optional specific embodiment, the titanium content in the scandium-containing organic phase is 500-1000 mg / L, for example, it can be 500 mg / L, 556 mg / L, 612 mg / L, 667 mg / L, 723 mg / L, 778 mg / L, 834 mg / L, 889 mg / L, 945 mg / L or 1000 mg / L, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0094] As a preferred technical solution of the present invention, the method includes n separation sections, wherein each separation section includes a sub-mixing section and a sub-clarification section, wherein the stirred mixed liquid obtained in the sub-mixing section enters the sub-clarification section for liquid-liquid phase separation to obtain an extracted organic phase and a raffinate of the corresponding separation section, wherein the extracted organic phase enters the sub-mixing section of the next separation section;

[0095] The process of running the method includes:

[0096] A first sulfuric acid solution with a concentration of 0.5 to 1.5 mol / L enters the second separation section, and a first raffinate is discharged from the first separation section; wherein the flow ratio of the first sulfuric acid solution to the scandium-containing organic phase is 0.03 to 0.05:1;

[0097] The scandium-containing organic phase is passed into the fourth separation section, and undergoes liquid-liquid separation in the fourth sub-clarification section to obtain a fourth raffinate. The fourth raffinate is passed into the third separation section and undergoes liquid-liquid separation in the third sub-clarification section, and then the third raffinate is discharged.

[0098] A second sulfuric acid solution having a sulfuric acid concentration of 0.5 to 1.5 mol / L is passed into the i-th separation section, with a flow ratio of the second sulfuric acid solution to the scandium-containing organic phase being 0.008 to 0.012:1. The i-th raffinate obtained enters the sub-mixing section of the previous separation section, and is continuously mixed until a fifth raffinate is obtained, which is then discharged.

[0099] Wherein, when the scandium-containing organic phase contains titanium, the second sulfuric acid solution is mixed with H2O2, and the mass concentration of H2O2 in the second sulfuric acid solution is 25-35wt%;

[0100] A hydrochloric acid solution with a concentration of 3 to 5 mol / L is passed into the jth separation section to wash the scandium in the scandium-containing organic phase into the jth raffinate. The obtained jth raffinate enters the sub-mixing section of the previous separation section, and the process is continued step by step until the i+1th raffinate is obtained. The i+1th raffinate is discharged, and the mass concentration of scandium chloride in the i+1th raffinate is 10 to 20 g / L. The flow ratio of the hydrochloric acid solution to the scandium-containing organic phase is 0.03 to 0.05:1.

[0101] A sodium carbonate solution with a concentration of 0.2 to 1.5 mol / L is passed into the nth separation section, and the obtained nth raffinate enters the sub-mixing section of the previous separation section, and the process is continued step by step until the j+1th raffinate is obtained, and the j+1th raffinate is discharged; and the pH of the j+1th raffinate is monitored to be within a range of 5.8 to 6.5; wherein the flow ratio of the sodium carbonate solution to the scandium-containing organic phase is 0.05 to 0.15:1;

[0102] Among them, the value range of i is 7 to 9, the value range of j is 12 to 15, the value range of n is 18 to 22, and n is the total number of separation stages.

[0103] The present invention has no limitation on the extractant in the above method. Any extractant known to those skilled in the art for extracting scandium can be used, for example, any one of N1923, n-dodecane or isooctyl alcohol, or a combination of at least two thereof.

[0104] For the convenience of experimental comparison, the solvent composition of the scandium-containing organic phase used in the following examples and comparative examples is N1923, n-dodecane, isooctyl alcohol and environmentally friendly cleaning agent (brand YT2426) in a mass ratio of 2:1:6:1, wherein the content of each element is shown in Table 1 below.

[0105] Table 1

[0106] Sc(mg / L) Co (mg / L) Ni(g / L) Fe(g / L) Ti (mg / L) 732.00 5269.59 47.45 0.35 757.00

[0107] Example 1

[0108] This embodiment provides a method for separating scandium from a scandium-containing organic phase, the method comprising the following steps:

[0109] 19 separation sections, wherein each separation section includes a sub-mixing section and a sub-clarification section, wherein the stirred mixed liquid obtained in the sub-mixing section enters the sub-clarification section for liquid-liquid phase separation to obtain the extracted organic phase and the raffinate of the corresponding separation section, wherein the extracted organic phase enters the sub-mixing section of the next separation section;

[0110] The process of running the method includes:

[0111] A first sulfuric acid solution having a concentration of 1.0 mol / L enters the second separation section, and a first raffinate is discharged from the first separation section; wherein the flow ratio of the first sulfuric acid solution to the scandium-containing organic phase is 0.04:1;

[0112] The scandium-containing organic phase is passed into the fourth separation section, and undergoes liquid-liquid separation in the fourth sub-clarification section to obtain a fourth raffinate. The fourth raffinate is passed into the third separation section and undergoes liquid-liquid separation in the third sub-clarification section, and then the third raffinate is discharged.

[0113] A second sulfuric acid solution having a sulfuric acid concentration of 1.0 mol / L is passed into the eighth separation section, with a flow ratio of the second sulfuric acid solution to the scandium-containing organic phase being 0.01:1. The resulting eighth raffinate enters the sub-mixing section of the previous separation section and is gradually transferred to the upper section until a fifth raffinate is obtained, which is then discharged.

[0114] Wherein, when the scandium-containing organic phase contains titanium, the second sulfuric acid solution is mixed with H2O2, and the mass concentration of H2O2 in the second sulfuric acid solution is 30wt%;

[0115] A hydrochloric acid solution with a concentration of 4 mol / L is passed into the 13th separation section to wash the scandium in the scandium-containing organic phase into the 13th raffinate. The obtained 13th raffinate enters the sub-mixing section of the previous separation section, and the process is continued step by step until the 9th raffinate is obtained. The 9th raffinate is discharged, and the mass concentration of scandium chloride in the 9th raffinate is 15 g / L. The flow ratio of the hydrochloric acid solution to the scandium-containing organic phase is 0.04:1.

[0116] A sodium carbonate solution with a concentration of 1.2 mol / L is passed into the 19th separation section, and the obtained 19th raffinate enters the sub-mixing section of the previous separation section, and the process is continued step by step until the 14th raffinate is obtained, and the 14th raffinate is discharged; and the pH of the 14th raffinate is monitored within a range of 6.0 to 6.5; wherein, the flow ratio of the sodium carbonate solution to the scandium-containing organic phase is 0.1:1.

[0117] The method for separating scandium from a scandium-containing organic phase provided in this embodiment can operate continuously for 30 days under the premise that the chloride ion content of the product is qualified, and the scandium removal rate reaches 99%, wherein the chloride ion concentration in the product is 35 mg / L.

[0118] Example 2

[0119] This embodiment provides a method for separating scandium from a scandium-containing organic phase, the method comprising the following steps:

[0120] There are 18 separation sections, each of which includes a sub-mixing section and a sub-clarifying section. The stirred mixed liquid obtained in the sub-mixing section enters the sub-clarifying section for liquid-liquid phase separation to obtain the extracted organic phase and the raffinate of the corresponding separation section. The extracted organic phase enters the sub-mixing section of the next separation section.

[0121] The process of running the method includes:

[0122] The first sulfuric acid solution with a concentration of 1.5 mol / L enters the second separation section, and the first raffinate is discharged from the first separation section. The flow ratio of the first sulfuric acid solution to the scandium-containing organic phase is 0.03:1.

[0123] The scandium-containing organic phase is passed into the fourth separation section, and the obtained fourth raffinate flows out of the third separation section. After liquid-liquid separation in the fourth sub-clarification section, a fourth raffinate is obtained. The fourth raffinate is passed into the third separation section and subjected to liquid-liquid separation in the third sub-clarification section to discharge the third raffinate.

[0124] A second sulfuric acid solution having a sulfuric acid concentration of 0.5 mol / L is passed into the seventh separation section, and the flow ratio of the second sulfuric acid solution to the scandium-containing organic phase is 0.012:1. The obtained seventh raffinate enters the sub-mixing section of the previous separation section, and is carried out step by step until the fifth raffinate is obtained, and the fifth raffinate is discharged.

[0125] Wherein, the second sulfuric acid solution is mixed with H2O2, and the mass concentration of H2O2 in the second sulfuric acid solution is 35wt%.

[0126] A 5 mol / L hydrochloric acid solution is passed into the 12th separation stage, washing the scandium from the scandium-containing organic phase into the 12th raffinate. The resulting 12th raffinate is then fed into the sub-mixing section of the previous separation stage. This process is continued step by step until the 8th raffinate is obtained, which is then discharged. The mass concentration of scandium chloride in the 8th raffinate is 10 g / L. The flow ratio of the hydrochloric acid solution to the scandium-containing organic phase is 0.03:1.

[0127] A 1.5 mol / L sodium carbonate solution was passed into the 18th separation stage. The resulting raffinate was fed into the sub-mixing section of the previous separation stage. This process was continued until the 13th raffinate was obtained, which was then discharged. The pH of the 13th raffinate was monitored to maintain a pH between 5.8 and 6.2. The flow ratio of the sodium carbonate solution to the scandium-containing organic phase was 0.15:1.

[0128] The method for separating scandium from a scandium-containing organic phase provided in this embodiment can operate continuously for 35 days under the premise that the chloride ion content of the product (nth extracted organic phase) is qualified, and the scandium removal rate reaches 99%, wherein the chloride ion content in the product is 32 mg / L.

[0129] Example 3

[0130] This embodiment provides a method for separating scandium from a scandium-containing organic phase, the method comprising the following steps:

[0131] There are 22 separation sections, each of which includes a sub-mixing section and a sub-clarifying section. The stirred mixed liquid obtained in the sub-mixing section enters the sub-clarifying section for liquid-liquid phase separation to obtain the extracted organic phase and the raffinate of the corresponding separation section. The aqueous phase enters the sub-mixing section of the previous separation section, and the extracted organic phase enters the sub-mixing section of the next separation section.

[0132] The process of running the method includes:

[0133] The first sulfuric acid solution with a concentration of 0.5 mol / L enters the second separation section, and the first raffinate is discharged from the first separation section. The flow ratio of the first sulfuric acid solution to the scandium-containing organic phase is 0.05:1.

[0134] The scandium-containing organic phase is passed into the fourth separation section, and undergoes liquid-liquid separation in the fourth sub-clarification section to obtain a fourth raffinate. The fourth raffinate is passed into the third separation section and undergoes liquid-liquid separation in the third sub-clarification section to discharge the third raffinate.

[0135] A second sulfuric acid solution having a sulfuric acid concentration of 1.5 mol / L is passed into the 9th separation section, and the flow ratio of the second sulfuric acid solution to the scandium-containing organic phase is 0.008:1. The obtained 9th raffinate enters the sub-mixing section of the previous separation section, and is carried out step by step until the 5th raffinate is obtained, and the 5th raffinate is discharged.

[0136] Wherein, the second sulfuric acid solution is mixed with H2O2, and the mass concentration of H2O2 in the second sulfuric acid solution is 25wt%.

[0137] A 3 mol / L hydrochloric acid solution is passed into the 14th separation stage, where the scandium in the scandium-containing organic phase is washed into the 14th raffinate. The 14th raffinate is then passed into the sub-mixing section of the previous separation stage. This process is continued step by step until the 10th raffinate is obtained, which is then discharged. The mass concentration of scandium chloride in the 10th raffinate is 20 g / L. The flow ratio of the hydrochloric acid solution to the scandium-containing organic phase is 0.05:1.

[0138] A 0.2 mol / L sodium carbonate solution was passed into the 22nd separation stage. The resulting raffinate was then fed into the sub-mixing section of the previous separation stage. This process was continued until the 15th raffinate was obtained, which was then discharged. The pH of the 15th raffinate was monitored to maintain a pH between 5.9 and 6.2. The flow ratio of the sodium carbonate solution to the scandium-containing organic phase was 0.05:1.

[0139] The method for separating scandium from a scandium-containing organic phase provided in this embodiment can operate continuously for 30 days under the premise that the chloride ion content of the product (nth extracted organic phase) is qualified, and the scandium removal rate reaches 99%, wherein the chloride ion content in the product is 28 mg / L.

[0140] Example 4

[0141] This embodiment provides a method for separating scandium from a scandium-containing organic phase. The method is the same as that in Example 1 except that the concentration of the sodium carbonate solution is 0.1 mol / L, and details thereof will not be repeated here.

[0142] The method for separating scandium from a scandium-containing organic phase provided in this embodiment has a chloride ion content in the product exceeding 40 mg / L after continuous operation for 0.5 days. This is because the concentration of the sodium carbonate solution is relatively low, which results in the chloride ions in the scandium-containing organic phase not being fully washed away. As a result, after the scandium-containing organic phase is circulated to the first separation stage, the chloride ion content in the aqueous raffinate of the third separation stage increases, resulting in the chloride ion concentration in the product (the nth extracted organic phase) exceeding the standard after 0.5 days of operation, making long-term stable operation difficult.

[0143] Example 5

[0144] This embodiment provides a method for separating scandium from a scandium-containing organic phase. The method is the same as that in Example 1 except that the concentration of the sodium carbonate solution is 2.0 mol / L, and details thereof will not be repeated here.

[0145] The method for separating scandium from a scandium-containing organic phase provided in this embodiment has serious oil-water mixing after continuous operation for 0.2 days, making it difficult to effectively separate oil and water. In severe cases, it will cause shutdown, making it difficult for the entire system to operate stably for a long time.

[0146] Example 6

[0147] This embodiment provides a method for separating scandium from a scandium-containing organic phase. The method is the same as that in Example 1 except that the flow ratio of the first sulfuric acid solution to the scandium-containing organic phase is 0.02:1, and thus will not be described in detail.

[0148] In the method for separating scandium from a scandium-containing organic phase provided in this embodiment, the flow rate of the first sulfuric acid solution is relatively low, so that the sodium carbonate entrained in the organic phase is brought to the front end of the production line. After 0.2 days of continuous operation, the oil-water phase is seriously mixed, and the oil and water are difficult to be effectively separated. In severe cases, it will cause shutdown, and the overall system is difficult to operate stably for a long time.

[0149] Example 7

[0150] This embodiment provides a method for separating scandium from a scandium-containing organic phase. The method is the same as that of Example 1 except that the flow ratio of the first sulfuric acid solution to the scandium-containing organic phase is 0.07:1, and thus will not be described in detail.

[0151] This embodiment can achieve a separation effect and an operating effect similar to that of embodiment 1, but the concentration of the discharged acid solution is too high, resulting in a waste of costs.

[0152] Example 8

[0153] This embodiment provides a method for separating scandium from a scandium-containing organic phase. The method is the same as that in Example 1 except that the flow ratio of the sodium carbonate solution to the scandium-containing organic phase is 0.01:1, and thus will not be described in detail.

[0154] This embodiment is difficult to obtain a product with a qualified chloride ion concentration and cannot meet production needs.

[0155] Example 9

[0156] This embodiment provides a method for separating scandium from a scandium-containing organic phase. The method is the same as that in Example 1 except that the flow ratio of the sodium carbonate solution to the scandium-containing organic phase is 0.2:1, and thus will not be described in detail.

[0157] In this embodiment, the organic phase is seriously mixed, and the machine needs to be shut down for clarification and separation, which makes it difficult to operate stably for a long time.

[0158] Comparative Example 1

[0159] This comparative example provides a method for separating scandium from a scandium-containing organic phase. The method is the same as Example 1 except that the first sulfuric acid solution is not introduced into the second separation section and the scandium-containing organic phase is introduced into the second separation section.

[0160] In this comparative example, the organic phase was seriously mixed and the machine could not be started for separation.

[0161] Comparative Example 2

[0162] This comparative example provides a method for separating scandium from a scandium-containing organic phase. The method is the same as Example 1 except that the sodium carbonate solution is not introduced into the 19th separation stage, and the details are not repeated here.

[0163] In this comparative example, the chloride ion seriously exceeds the standard, and it is difficult to obtain a product that meets the expectations.

[0164] Comparative Example 3

[0165] This comparative example provides a method for separating scandium from a scandium-containing organic phase, the method comprising the following steps:

[0166] There are 19 separation sections, each of which includes a sub-mixing section and a sub-clarifying section. The stirred mixed liquid obtained in the sub-mixing section enters the sub-clarifying section for liquid-liquid phase separation to obtain the extracted organic phase and the raffinate of the corresponding separation section. The extracted organic phase enters the sub-mixing section of the next separation section.

[0167] The process of running the method includes:

[0168] The scandium-containing organic phase is introduced into the second separation section, and the first raffinate is discharged from the first separation section.

[0169] A second sulfuric acid solution having a sulfuric acid concentration of 1.0 mol / L is passed into the eighth separation section, and the flow ratio of the second sulfuric acid solution to the scandium-containing organic phase is 0.01:1. The eighth raffinate obtained enters the sub-mixing section of the previous separation section, and is processed step by step until the third raffinate is obtained, and the third raffinate is discharged.

[0170] When the scandium-containing organic phase contains titanium, H2O2 is mixed in the second sulfuric acid solution, and the mass concentration of H2O2 in the second sulfuric acid solution is 30 wt%.

[0171] A 4 mol / L hydrochloric acid solution is passed through the 13th separation stage, where the scandium in the organic phase containing scandium is washed into the 13th raffinate. This 13th raffinate is then fed into the sub-mixing section of the previous separation stage. This process continues until the 9th raffinate is obtained, which is then discharged. The scandium chloride concentration in the 9th raffinate is 15 g / L. The flow ratio of the hydrochloric acid solution to the organic phase containing scandium is 0.04:1. The pH of the 14th aqueous phase is monitored to maintain a pH between 6.0 and 6.5.

[0172] A 4.5 mol / L sulfuric acid solution was passed into the 19th separation stage. The resulting raffinate was fed into the sub-mixing section of the previous separation stage. This process was continued until the 14th raffinate was obtained, which was then discharged. The pH of the 14th raffinate was monitored to maintain a pH between 5.8 and 6.5. The flow ratio of the sulfuric acid solution to the scandium-containing organic phase was 0.1:1, and the chloride ion concentration of the 1st raffinate was monitored.

[0173] During operation, this comparative example not only suffers from severe phase miscibility, making it difficult to separate oil and water, but also has a chloride ion concentration in the product that exceeds the standard, making it difficult to obtain a product that meets the expected chloride ion concentration.

[0174] Test method: The shutdown standard is determined by taking the chloride ion concentration in the product exceeding 40 mg / L or the organic phase content in the product exceeding 5%. The above embodiments and comparative examples are tested and run, and the continuous running time is recorded.

[0175] The present invention uses the above-described embodiments to illustrate the detailed features of the present invention. However, the present invention is not limited to the above-described detailed features, which does not mean that the present invention must rely on the above-described detailed features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for the selected technical features of the present invention, additions to auxiliary technical features, and selections of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for separating scandium from a scandium-containing organic phase, characterized in that: The method comprises n separation sections, wherein each separation section comprises a sub-mixing section and a sub-clarifying section, wherein the stirred mixed liquid obtained in the sub-mixing section enters the sub-clarifying section for liquid-liquid phase separation to obtain an extracted organic phase and a raffinate of the corresponding separation section, wherein the extracted organic phase enters the sub-mixing section of the next separation section; The process of running the method includes: The first sulfuric acid solution is passed into the second sub-mixing section of the second separation section, and the first raffinate is discharged from the first separation section; The scandium-containing organic phase is passed into the fourth sub-mixing section of the fourth separation section, and undergoes liquid-liquid separation in the fourth sub-clarification section to obtain a fourth raffinate. The fourth raffinate is passed into the third separation section and undergoes liquid-liquid separation in the third sub-clarification section, and then a third raffinate is discharged. The second sulfuric acid solution is passed into the i-th sub-mixing section of the i-th separation section, and the i-th raffinate obtained is passed into the sub-mixing section of the previous separation section, and the process is continued step by step until the fifth raffinate is obtained, and the fifth raffinate is discharged; The hydrochloric acid solution is passed into the jth sub-mixing section of the jth separation section to wash the scandium in the scandium-containing organic phase into the jth raffinate. The obtained jth raffinate is passed into the sub-mixing section of the previous separation section, and the process is continued step by step until the i+1th raffinate is obtained, and the i+1th raffinate is discharged. The sodium carbonate solution is passed into the nth sub-mixing section of the nth separation section, and the obtained nth raffinate enters the sub-mixing section of the previous separation section, and the process is continued step by step until the j+1th raffinate is obtained, and the j+1th raffinate is discharged; Wherein, i and j are each independently an integer from 4 to n, i is smaller than j, and n is the total number of separation stages.

2. The method according to claim 1, characterized in that The concentration of the first sulfuric acid solution is 0.5 to 1.5 mol / L; Preferably, the flow ratio of the first sulfuric acid solution to the scandium-containing organic phase is 0.03 to 0.05:1; Preferably, the Sc concentration in the third raffinate is less than 5 mg / L.

3. The method according to claim 1 or 2, characterized in that The sulfuric acid concentration of the second sulfuric acid solution is 0.5 to 1.5 mol / L; Preferably, the flow ratio of the second sulfuric acid solution to the scandium-containing organic phase is 0.008-0.012:

1.

4. The method according to any one of claims 1 to 3, characterized in that When the scandium-containing organic phase contains titanium, the second sulfuric acid-containing solution is mixed with H2O2; Preferably, the mass concentration of H2O2 in the second sulfuric acid solution is 25-35 wt%.

5. The method according to any one of claims 1 to 4, characterized in that The concentration of the hydrochloric acid solution is 3 to 5 mol / L; Preferably, the flow ratio of the hydrochloric acid solution to the scandium-containing organic phase is 0.03 to 0.05:1; Preferably, the mass concentration of scandium in the (i+1) raffinate is 10-20 g / L.

6. The method according to any one of claims 1 to 5, characterized in that The concentration of the sodium carbonate solution is 0.2 to 1.5 mol / L; Preferably, the flow ratio of the sodium carbonate solution to the scandium-containing organic phase is 0.05-0.15:

1.

7. The method according to any one of claims 1 to 6, characterized in that During the operation of the method, the pH of the j+1 raffinate is monitored to be within a first value; Preferably, the first value ranges from 5.8 to 6.

5.

8. The method according to any one of claims 1 to 7, characterized in that The value range of i is 7 to 9; Preferably, the value range of j is 12 to 15; Preferably, the value range of n is 18-22.

9. The method according to any one of claims 1 to 8, characterized in that The nickel content in the scandium-containing organic phase is 30 to 50 g / L; Preferably, the cobalt content in the scandium-containing organic phase is 3000 to 7000 mg / L; Preferably, the scandium content in the scandium-containing organic phase is 600-800 mg / L; Preferably, the scandium-containing organic phase further comprises iron and / or titanium; Preferably, the iron content in the scandium-containing organic phase is 0.2 to 0.5 g / L; Preferably, the titanium content in the scandium-containing organic phase is 500-1000 mg / L.

10. The method according to any one of claims 1 to 9, characterized in that The method comprises n separation sections, wherein each separation section comprises a sub-mixing section and a sub-clarifying section, wherein the stirred mixed liquid obtained in the sub-mixing section enters the sub-clarifying section for liquid-liquid phase separation to obtain an extracted organic phase and a raffinate of the corresponding separation section, wherein the extracted organic phase enters the sub-mixing section of the next separation section; The process of running the method includes: A first sulfuric acid solution with a concentration of 0.5 to 1.5 mol / L enters the second separation section, and a first raffinate is discharged from the first separation section; wherein the flow ratio of the first sulfuric acid solution to the scandium-containing organic phase is 0.03 to 0.05:1; The scandium-containing organic phase is passed into the fourth separation section, and undergoes liquid-liquid separation in the fourth sub-clarification section to obtain a fourth raffinate. The fourth raffinate is passed into the third separation section and undergoes liquid-liquid separation in the third sub-clarification section, and then the third raffinate is discharged. A second sulfuric acid solution having a sulfuric acid concentration of 0.5 to 1.5 mol / L is passed into the i-th separation section, with a flow ratio of the second sulfuric acid solution to the scandium-containing organic phase being 0.008 to 0.012:

1. The i-th raffinate obtained enters the sub-mixing section of the previous separation section, and is continuously mixed until a fifth raffinate is obtained, which is then discharged. Wherein, when the scandium-containing organic phase contains titanium, the second sulfuric acid solution is mixed with H2O2, and the mass concentration of H2O2 in the second sulfuric acid solution is 25-35wt%; A hydrochloric acid solution with a concentration of 3 to 5 mol / L is passed into the jth separation section to wash the scandium in the scandium-containing organic phase into the jth raffinate. The obtained jth raffinate enters the sub-mixing section of the previous separation section, and the process is continued step by step until the i+1th raffinate is obtained. The i+1th raffinate is discharged, and the mass concentration of scandium chloride in the i+1th raffinate is 10 to 20 g / L. The flow ratio of the hydrochloric acid solution to the scandium-containing organic phase is 0.03 to 0.05:

1. A sodium carbonate solution with a concentration of 0.2 to 1.5 mol / L is passed into the nth separation section, and the obtained nth raffinate enters the sub-mixing section of the previous separation section, and the process is continued step by step until the j+1th raffinate is obtained, and the j+1th raffinate is discharged; and the pH of the j+1th raffinate is monitored to be within a range of 5.8 to 6.5; wherein the flow ratio of the sodium carbonate solution to the scandium-containing organic phase is 0.05 to 0.15:1; Among them, the value range of i is 7 to 9, the value range of j is 12 to 15, the value range of n is 18 to 22, and n is the total number of separation stages.

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