Method for recovering scandium through extraction method and washing chlorine through organic phase after reverse extraction

Abstract

The invention relates to a method for recovering scandium through an extraction method and washing chlorine through an organic phase after reverse extraction, and the method comprises the following steps: carrying out counter-current extraction on scandium-containing waste liquid by adopting a solvent extraction method to obtain raffinate and a scandium-loaded organic phase; performing countercurrent washing on the scandium-loaded organic phase by using an acid solution to obtain a washing solution and a washed scandium-loaded organic phase; the washed scandium-loaded organic phase is subjected to countercurrent reverse extraction with hydrochloric acid, and scandium-containing reverse extraction liquid and a reverse extraction organic phase are obtained; and carrying out chlorine washing on the reverse-extracted organic phase by using a 0.5 N-1. 5N regenerant to obtain a regenerated organic phase. By optimizing extraction and reverse extraction processes, efficient separation of low-concentration scandium from cobalt, nickel, manganese and other elements in the scandium-containing waste liquid is achieved, the scandium extraction rate is high, the scandium in the obtained scandium-containing reverse extraction liquid is enriched in a high concentration, the scandium recovery efficiency is greatly improved, then a regenerant with the concentration of 0.5 N-1. 5N is adopted for chlorine washing regeneration of a chlorine-containing reverse extraction organic phase, and the recovery rate of the scandium is greatly improved. And residual chloride ions in an organic phase after reverse extraction can be effectively removed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of scandium collection and organic phase regeneration after stripping, and particularly relates to a method for recovering scandium by extraction and washing chlorides after stripping. BACKGROUND

[0002] Scandium (Sc) is a rare metal and is widely used in the fields of aerospace, electronics industry, medical equipment, etc. However, the extraction and separation process of scandium is complex, especially the scandium-containing waste liquid in industry, such as waste liquid produced in the production of titanium dioxide by the sulfuric acid method, waste liquid produced in the titanium extraction process by the chlorination method, waste liquid produced in the extraction of aluminum from bauxite, or water in the primary washing residue of nickel-cobalt hydroxide, all of which contain different amounts of scandium and other metal elements, especially in the primary washing residue of nickel-cobalt hydroxide, the content of scandium is low and often coexists with other metal elements, which makes it difficult to separate and enrich.

[0003] CN117701920A discloses a method for extracting and recovering scandium elements from laterite nickel ore. A secondary amine extractant is dissolved in an organic solvent to form an organic phase, which is mixed with a scandium-containing laterite nickel ore leaching solution to extract a scandium-containing organic phase, and then washing and stripping are performed. The scandium extraction rate can reach more than 75% in a single-stage extraction, preferably more than 80%, such as more than 85%, more than 90%, and after single-stage extraction and stripping, the stripping rate can reach 100%. However, a large amount of organic solvent is used in the extraction process, including sulfonated kerosene, toluene, n-dodecane, p-umbelliferone, n-heptane, n-hexane, cyclohexane, cyclopentane, petroleum ether, etc. The organic phase also includes a phase modifier (organic solvent), including tributyl phosphate, methyl phosphonic acid dimethyl heptyl ester, methyl phosphonic acid diisopentyl ester, dodecanol, tetradecanol, hexadecanol, octadecanol, 1,2-decanediol, 1,2-dodecanediol, menthol, nonyl phenol, thymol, etc. Therefore, the waste liquid generated in the extraction process is significantly increased, and the treatment of organic waste liquid generated by different organic matters is also different, which increases the treatment time and cost.

[0004] In addition, in the existing stripping process, the stripping effect of the chloride-containing stripping solution is good, which can realize high-concentration enrichment of scandium stripping, but the problem of easy combination of the organic phase with chloride ions (Cl-) after stripping is common, which further leads to the decrease of the capacity of the extractant and increases the possibility of emulsification of the organic phase. Therefore, sulfuric acid is generally used for regeneration in the process, but the acidity of sulfuric acid in the regeneration process can cause serious emulsification of the organic phase.

[0005] Therefore, how to provide a method for effectively extracting and enriching scandium from scandium-containing waste liquid, and effectively solving the problem of the combination of the organic phase after stripping with chloride ions affecting the subsequent stability and extraction capacity of the extractant due to the use of chloride-containing stripping agent, has become a technical problem to be solved at present. SUMMARY

[0006] To solve the above technical problems, the present application provides a method for recovering scandium by extraction and washing chlorine from the organic phase after stripping. By optimizing the extraction process and stripping process, the present application realizes efficient separation of low-concentration scandium from cobalt, nickel, manganese and other elements in scandium-containing waste liquid, has high scandium extraction rate, and enriches high-concentration scandium in the obtained scandium-containing stripping liquid, greatly improves the scandium recovery efficiency, and then uses a regenerant with a concentration of 0.5N-1.5N to wash and regenerate the chlorine-containing organic phase after stripping, which can effectively remove the residual chlorine ions in the organic phase, avoid affecting the subsequent semi-extraction process, and also improve the stability and extraction efficiency of the extractant, so that the production line can run smoothly.

[0007] To achieve this purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a method for recovering scandium by extraction and washing chlorine from the organic phase after stripping, which comprises the following steps:

[0009] (1) The scandium-containing waste liquid is subjected to countercurrent extraction separation by solvent extraction to obtain raffinate and scandium-loaded organic phase;

[0010] (2) The scandium-loaded organic phase of step (1) is subjected to countercurrent washing with acid solution to obtain washing liquid and washed scandium-loaded organic phase;

[0011] (3) The washed scandium-loaded organic phase of step (2) is subjected to countercurrent stripping separation with hydrochloric acid to obtain scandium-containing stripping liquid and organic phase after stripping;

[0012] (4) The organic phase after stripping of step (3) is treated with a regenerant with a concentration of 0.5N-1.5N to obtain regenerated organic phase, for example, the concentration of the regenerant can be 0.5N, 0.6N, 0.7N, 0.8N, 0.9N, 1N, 1.1N, 1.2N, 1.3N, 1.4N or 1.5N, etc.

[0013] The application firstly adopts solvent extraction method to carry out countercurrent extraction separation on the scandium-containing waste liquid, realizes extraction of low-concentration scandium in the scandium-containing waste liquid by optimizing the countercurrent extraction process, then washes the obtained scandium-loaded organic phase with acid liquid, which can effectively remove impurity ions such as iron or aluminum in the organic phase, so that the purity of the subsequent obtained scandium is higher, then countercurrent stripping separation is carried out on the washed scandium-loaded organic phase by using hydrochloric acid as the stripping liquid, which enhances the stripping effect of scandium, can realize high-concentration enrichment of scandium, greatly improves the scandium recovery efficiency, then the organic phase after stripping is subjected to chlorine washing treatment, by using 0.5N-1.5N regenerant, the chloride ions in the organic phase can be effectively removed, the stability and extraction capacity of the extractant are significantly improved. If the concentration of the regenerant is too low, the washing effect of the chloride ions in the organic phase will be poor, and the residual chloride ions in the organic phase cannot be completely removed, and the stability and extraction efficiency of the extractant are not obviously improved. If the concentration of the regenerant is too high, the removal rate of the chloride ions will not be greatly improved, but the consumption of the regenerant will be increased, resulting in increased cost. Therefore, the 0.5N-1.5N regenerant can effectively remove the impurity chloride ions in the organic phase without any adverse effects on the performance of the extractant, and the stability and extraction efficiency of the extractant are improved.

[0014] As a preferred technical solution of the application, the scandium-containing waste liquid in step (1) has a scandium concentration of 700 mg / L-800 mg / L, for example, 700 mg / L, 710 mg / L, 720 mg / L, 730 mg / L, 740 mg / L, 750 mg / L, 760 mg / L, 770 mg / L, 780 mg / L, 790 mg / L or 800 mg / L.

[0015] Preferably, the pH of the scandium-containing waste liquid in step (1) is 0.5-1, for example, 0.5, 0.6, 0.7, 0.8, 0.9 or 1, etc.

[0016] Preferably, the scandium-containing waste liquid in step (1) includes MHP primary washing residue water and / or MHP leaching liquid.

[0017] Preferably, the solvent used in the solvent extraction method in step (1) includes an N1923 extractant solution.

[0018] Preferably, the N1923 extractant solution includes an N1923 extractant and a solvent.

[0019] In the application, the N1923 extractant does not need to be saponified.

[0020] Preferably, the solvent includes sulfonated kerosene and / or n-dodecane.

[0021] Preferably, the content of the N1923 extractant is 10wt%-25wt%, such as 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 22wt% or 25wt%, etc., based on the total mass of the N1923 extractant solution being 100wt%.

[0022] Preferably, the content of the solvent is 75wt%-90wt%, such as 75wt%, 78wt%, 80wt%, 82wt%, 85wt%, 88wt% or 90wt%, etc., based on the total mass of the N1923 extractant solution being 100wt%.

[0023] As a preferred technical solution of the present application, the number of stages of countercurrent extraction in step (1) is 2-3 stages, such as 2 stages or 3 stages, etc.

[0024] Preferably, the temperature of countercurrent extraction in step (1) is 25°C-50°C, such as 25°C, 30°C, 35°C, 40°C, 45°C or 50°C, etc.

[0025] As a preferred technical solution of the present application, the flow rate of the scandium-containing waste liquid during countercurrent extraction in step (1) is 500L / h-600L / h, such as 500L / h, 510L / h, 520L / h, 530L / h, 540L / h, 550L / h, 560L / h, 570L / h, 580L / h, 590L / h or 600L / h, etc.

[0026] Preferably, the flow rate of the N1923 extractant solution during countercurrent extraction in step (1) is 100L / h-120L / h, such as 100L / h, 102L / h, 105L / h, 108L / h, 110L / h, 112L / h, 115L / h, 118L / h or 120L / h, etc.

[0027] In the present application, the number of stages of countercurrent extraction is regulated to be 2-3 stages, the flow rate of the scandium-containing waste liquid is 500L / h-600L / h, and the flow rate of the N1923 extractant solution is 100L / h-120L / h. Matching the flow rates and the number of stages can take into account both the efficiency and the cost of extraction and separation. If the number of stages of extraction is too large or the flow rates of the scandium-containing waste liquid and the N1923 extractant solution are too slow, the extraction effect is comparable, but the extraction time is additionally increased, and the cost of extraction is also increased. If the number of stages of extraction is too small or the flow rates of the scandium-containing waste liquid and the N1923 extractant solution are too fast, the extraction effect is greatly reduced, and for the low-concentration scandium and other metal elements in the scandium-containing waste liquid of the present application, effective separation cannot be achieved.

[0028] As a preferred technical solution of the present application, the number of stages of countercurrent washing in step (2) is 4-6 stages, such as 4 stages, 5 stages or 6 stages, etc.

[0029] Preferably, the temperature of the countercurrent washing in step (2) is 25-50℃, such as 25℃, 30℃, 35℃, 40℃, 45℃ or 50℃, etc.

[0030] Preferably, the acid solution in step (2) comprises dilute sulfuric acid and / or dilute hydrochloric acid.

[0031] Preferably, the concentration of the acid solution in step (2) is 1N-2N, such as 1N, 1.2N, 1.4N, 1.6N, 1.8N or 2N, etc.

[0032] As a preferred technical solution of the present application, the flow rate of the scandium-loaded organic phase during the countercurrent washing in step (2) is 100-120L / h, such as 100L / h, 102L / h, 105L / h, 108L / h, 110L / h, 112L / h, 115L / h, 118L / h or 120L / h, etc.

[0033] Preferably, the flow rate of the acid solution during the countercurrent washing in step (2) is 20-30L / h, such as 20L / h, 22L / h, 24L / h, 26L / h, 28L / h, 30L / h, etc.

[0034] In the present application, the number of stages of the countercurrent washing is 4-6, the flow rate of the scandium-loaded organic phase is 100-120L / h, and the flow rate of the acid solution is 20-30L / h. Matching the flow rates and the number of stages can take into account both the washing effect and the cost. If the number of stages of the countercurrent washing is too large or the flow rates of the scandium-loaded organic phase and the acid solution are too slow, although the iron, aluminum and other impurity ions in the scandium-loaded organic phase can be removed, the washing time is additionally increased, and the washing cost is also increased. If the number of stages of the countercurrent washing is too small or the flow rates of the scandium-loaded organic phase and the acid solution are too fast, the washing effect is greatly reduced, impurity ions are mixed in the subsequent countercurrent stripping process, which affects the countercurrent stripping of scandium, and also affects the purity of the recovered scandium.

[0035] As a preferred technical solution of the present application, the number of stages of the countercurrent stripping in step (3) is 4-6, such as 4, 5 or 6, etc.

[0036] Preferably, the temperature of the countercurrent stripping in step (3) is 25-50℃, such as 25℃, 30℃, 35℃, 40℃, 45℃ or 50℃, etc.

[0037] Preferably, the concentration of the hydrochloric acid in step (3) is 2N-4N, such as 2N, 2.2N, 2.4N, 2.6N, 2.8N, 3N, 3.2N, 3.4N, 3.6N, 3.8N or 4N, etc.

[0038] In the present application, the concentration of hydrochloric acid in the countercurrent stripping process of step (3) is 2N-4N, which can effectively recover scandium and does not introduce excessive chloride ions in the organic phase. If the concentration of hydrochloric acid is too high, the content of residual chloride ions in the organic phase will be too high, the stability and extraction efficiency of the extractant will be significantly reduced, which is not conducive to the subsequent regeneration process and increases the difficulty of regeneration. If the concentration of hydrochloric acid is too low, effective high-concentration enrichment of scandium cannot be achieved, and scandium cannot be effectively recovered.

[0039] As a preferred technical solution of the present application, the flow rate of the washed scandium-loaded organic phase in the countercurrent stripping process of step (3) is 100L / h-120L / h, such as 100L / h, 102L / h, 105L / h, 108L / h, 110L / h, 112L / h, 115L / h, 118L / h or 120L / h, etc.

[0040] Preferably, in the countercurrent stripping process of step (3), the flow rate of the hydrochloric acid is 20L / h-30L / h, such as 20L / h, 22L / h, 24L / h, 26L / h, 28L / h, 30L / h, etc.

[0041] In the present application, the number of countercurrent stripping stages is 4-6, the flow rate of the washed scandium-loaded organic phase is 100L / h-120L / h, and the flow rate of the hydrochloric acid is 20L / h-30L / h. By matching the flow rates and the number of stages, the effect and cost of countercurrent stripping can be considered. If the number of countercurrent stripping stages is too high or the flow rates of the washed scandium-loaded organic phase and the hydrochloric acid are too slow, the enrichment of scandium does not significantly increase, and the time and cost of countercurrent stripping are also increased. If the number of countercurrent stripping stages is too low or the flow rates of the washed scandium-loaded organic phase and the hydrochloric acid are too fast, there is still some scandium in the organic phase after stripping, which affects the enrichment of scandium.

[0042] As a preferred technical solution of the present application, the washing and chlorination treatment of step (4) is a countercurrent stripping treatment.

[0043] Preferably, the number of stages of washing and chlorination in step (4) is 4-6, such as 4, 5 or 6, etc.

[0044] Preferably, the temperature of washing and chlorination in step (4) is 25℃-50℃, such as 25℃, 30℃, 35℃, 40℃, 45℃ or 50℃, etc.

[0045] Preferably, the regenerant of step (4) comprises sodium carbonate and / or sodium hydroxide.

[0046] As a preferred technical scheme of the present application, in the washing with chlorine process of step (4), the flow rate of the organic phase after stripping is 100 L / h-120 L / h, for example 100 L / h, 102 L / h, 105 L / h, 108 L / h, 110 L / h, 112 L / h, 115 L / h, 118 L / h or 120 L / h, etc.

[0047] Preferably, in the washing with chlorine process of step (4), the flow rate of the regenerant is 25 L / h-30 L / h, for example 25 L / h, 26 L / h, 27 L / h, 28 L / h, 29 L / h, 30 L / h, etc.

[0048] In the present application, the number of stages of the washing with chlorine process is 4-6, the flow rate of the organic phase after stripping is 100 L / h-120 L / h, and the flow rate of the regenerant is 25 L / h-30 L / h. By matching the flow rates and the number of stages, the effect and cost of the washing with chlorine process can be considered. If the number of stages of the washing with chlorine process is too large or the flow rates of the organic phase after stripping and the regenerant are too slow, the removal rate of chlorine ions does not increase significantly, and the time and cost of the washing with chlorine process are also increased. If the number of stages of the washing with chlorine process is too small or the flow rates of the organic phase after stripping and the regenerant are too fast, the effect of the regeneration of the extractant is poor.

[0049] As a preferred technical scheme of the present application, the method comprises the following steps:

[0050] (1) The scandium-containing waste liquid with a scandium concentration of 700 mg / L-800 mg / L and a pH of 0.5-1 is subjected to countercurrent extraction separation at 25℃-50℃ using N1923 extractant solution, the flow rate of the scandium-containing waste liquid is 500 L / h-600 L / h, the flow rate of the N1923 extractant solution is 100 L / h-120 L / h, the number of stages of the countercurrent extraction is 2-3, and a raffinate and a scandium-loaded organic phase are obtained;

[0051] The N1923 extractant solution comprises N1923 extractant and a solvent, and the content of the N1923 extractant is 10wt%-25wt% and the content of the solvent is 75wt%-90wt% based on 100wt% of the total mass of the N1923 extractant solution.

[0052] (2) The scandium-loaded organic phase of step (1) is subjected to countercurrent washing at 25℃-50℃ using acid solution with a concentration of 1N-2N, the flow rate of the scandium-loaded organic phase is 100 L / h-120 L / h, the flow rate of the acid solution is 20 L / h-30 L / h, the number of stages of the countercurrent washing is 4-6, and a washing liquid and a washed scandium-loaded organic phase are obtained.

[0053] (3) using 2N-4N hydrochloric acid to perform countercurrent stripping separation on the washed scandium-loaded organic phase obtained in step (2) at 25-50°C, the flow rate of the washed scandium-loaded organic phase being 100-120 L / h, the flow rate of the hydrochloric acid being 20-30 L / h, and the countercurrent stripping being performed for 4-6 stages, to obtain a scandium-containing stripping solution and a stripped organic phase;

[0054] (4) using 0.5N-1.5N regenerant to perform chlorine washing treatment on the stripped organic phase obtained in step (3) at 25-50°C, the flow rate of the stripped organic phase being 100-120 L / h, the flow rate of the regenerant being 25-30 L / h, and the chlorine washing being performed for 4-6 stages, to obtain a regenerated organic phase.

[0055] Compared with the prior art, the present application has at least the following beneficial effects:

[0056] 1) The present application realizes efficient separation of low-concentration scandium from cobalt, nickel, manganese and other elements in the scandium-containing waste solution through an optimized extraction process, and the scandium extraction rate is 98.8% or higher.

[0057] 2) The present application realizes high-concentration enrichment of scandium in the obtained scandium-containing stripping solution through an optimized stripping process, and the scandium concentration can be enriched to 10 g / L or higher, greatly improving the scandium recovery efficiency.

[0058] 3) The present application uses a regenerant with a proper concentration of 0.5N-1.5N to perform chlorine washing regeneration on the chlorine-containing stripped organic phase, effectively removing chlorine ions in the organic phase, and the removal rate can be 90% or higher, significantly improving the stability and extraction capacity of the extractant, and facilitating recycling. DETAILED DESCRIPTION

[0059] To facilitate understanding of the present application, the present application is illustrated by the following examples. Those skilled in the art should understand that the examples are only used to help understand the present application, and should not be regarded as a specific limitation on the present application.

[0060] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0061] The scandium-containing waste solution used in the specific mode part of the present application is all MHP primary washing residue water in industry, and it is detected that it contains Co 3.8 g / L, Ni 50 g / L, Mn 3.23 g / L, Cu 8.7 g / L, Ca 0.74 g / L, Mg 1.39 g / L, Fe 0.018 g / L, Al 6.03 g / L, Zn 1.65 g / L and Sc 0.74 g / L.

[0062] Example 1

[0063] The embodiment provides a method for recovering scandium by extraction and washing chlorine from an organic phase after stripping, and the method comprises the following steps:

[0064] (1) adjusting pH of MHP primary washing residue water to 0.6, and performing countercurrent extraction separation on the MHP primary washing residue water by using N1923 extractant solution (including 15 wt% of N1923 extractant and 85 wt% of sulfonated kerosene) at 25°C, the flow rate of the MHP primary washing residue water is 500 L / h, the flow rate of the N1923 extractant solution is 100 L / h, the countercurrent extraction is performed for 2 stages, and the raffinate and a scandium-loaded organic phase are obtained;

[0065] (2) performing countercurrent washing on the scandium-loaded organic phase in step (1) by using dilute sulfuric acid with a concentration of 1N at 25°C, the flow rate of the scandium-loaded organic phase is 100 L / h, the flow rate of the dilute sulfuric acid is 20 L / h, the washing is performed for 6 stages, and the washing liquid and the washed scandium-loaded organic phase are obtained;

[0066] (3) performing countercurrent stripping separation on the washed scandium-loaded organic phase in step (2) by using hydrochloric acid with a concentration of 3N at 25°C, the flow rate of the washed scandium-loaded organic phase is 100 L / h, the flow rate of the hydrochloric acid is 20 L / h, the countercurrent stripping is performed for 5 stages, and the scandium-containing stripping liquid and the stripped organic phase are obtained;

[0067] (4) performing chlorine washing treatment (countercurrent stripping) on the stripped organic phase in step (3) by using sodium carbonate with a concentration of 0.5N at 25°C, the flow rate of the stripped organic phase is 100 L / h, the flow rate of the sodium carbonate is 30 L / h, the chlorine washing is performed for 6 stages, and the regenerated organic phase is obtained.

[0068] Embodiment 2

[0069] The embodiment provides a method for recovering scandium by extraction and washing chlorine from an organic phase after stripping, and the method comprises the following steps:

[0070] (1) adjusting pH of MHP primary washing residue water to 0.5, and performing countercurrent extraction separation on the MHP primary washing residue water by using N1923 extractant solution (including 10 wt% of N1923 extractant and 90 wt% of sulfonated kerosene) at 25°C, the flow rate of the MHP primary washing residue water is 500 L / h, the flow rate of the N1923 extractant solution is 100 L / h, the countercurrent extraction is performed for 2 stages, and the raffinate and a scandium-loaded organic phase are obtained;

[0071] (2) performing countercurrent washing on the scandium-loaded organic phase in step (1) by using dilute sulfuric acid with a concentration of 1N at 25°C, the flow rate of the scandium-loaded organic phase is 100 L / h, the flow rate of the dilute sulfuric acid is 20 L / h, the washing is performed for 4 stages, and the washing liquid and the washed scandium-loaded organic phase are obtained;

[0072] (3) The washed loaded scandium organic phase of step (2) is subjected to countercurrent stripping separation using 2N hydrochloric acid at 25°C, the flow rate of the washed loaded scandium organic phase is 100 L / h, the flow rate of the hydrochloric acid is 20 L / h, and the countercurrent stripping is performed for 4 stages to obtain a scandium-containing stripping solution and a stripped organic phase;

[0073] (4) The stripped organic phase of step (3) is subjected to chlorine washing treatment (countercurrent stripping) using 0.5N sodium hydroxide at 25°C, the flow rate of the stripped organic phase is 100 L / h, the flow rate of the sodium hydroxide is 25 L / h, and the chlorine washing is performed for 4 stages to obtain a regenerated organic phase.

[0074] Example 3

[0075] The present example provides a method for recovering scandium by extraction and washing the chlorine of the stripped organic phase, which comprises the following steps:

[0076] (1) The MHP primary washing residue water is adjusted to a pH of 1, and subjected to countercurrent extraction separation using N1923 extractant solution (including 25wt% N1923 extractant and 75wt% sulfonated kerosene) at 25°C, the flow rate of the MHP primary washing residue water is 600 L / h, the flow rate of the N1923 extractant solution is 120 L / h, and the countercurrent extraction is performed for 3 stages to obtain a raffinate and a loaded scandium organic phase;

[0077] (2) The loaded scandium organic phase of step (1) is subjected to countercurrent washing using 2N dilute sulfuric acid at 25°C, the flow rate of the loaded scandium organic phase is 120 L / h, the flow rate of the dilute sulfuric acid is 30 L / h, and the washing is performed for 6 stages to obtain a washing solution and a washed loaded scandium organic phase;

[0078] (3) The washed loaded scandium organic phase of step (2) is subjected to countercurrent stripping separation using 4N hydrochloric acid at 25°C, the flow rate of the washed loaded scandium organic phase is 120 L / h, the flow rate of the hydrochloric acid is 30 L / h, and the countercurrent stripping is performed for 6 stages to obtain a scandium-containing stripping solution and a stripped organic phase;

[0079] (4) The stripped organic phase of step (3) is subjected to chlorine washing treatment (countercurrent stripping) using 1.5N sodium hydroxide at 25°C, the flow rate of the stripped organic phase is 120 L / h, the flow rate of the sodium hydroxide is 30 L / h, and the chlorine washing is performed for 6 stages to obtain a regenerated organic phase.

[0080] Example 4

[0081] The present example provides a method for recovering scandium by extraction and washing the chlorine of the stripped organic phase, which is different from Example 1 in that the concentration of the hydrochloric acid in step (3) is 1N, and the rest of the preparation method and parameters are consistent with Example 1.

[0082] Example 5

[0083] The embodiment provides a method for recovering scandium by extraction and washing chloro by organic phase after back extraction, which is different from the embodiment 1 in that the concentration of hydrochloric acid in step (3) is 5N, and the rest of the preparation method and parameters are consistent with the embodiment 1.

[0084] Embodiment 6

[0085] The embodiment provides a method for recovering scandium by extraction and washing chloro by organic phase after back extraction, which is different from the embodiment 1 in that the number of stages of washing chloro in step (4) is 7, and the rest of the preparation method and parameters are consistent with the embodiment 1.

[0086] Embodiment 7

[0087] The embodiment provides a method for recovering scandium by extraction and washing chloro by organic phase after back extraction, which is different from the embodiment 1 in that the number of stages of countercurrent back extraction in step (3) is 7, and the rest of the preparation method and parameters are consistent with the embodiment 1.

[0088] Embodiment 8

[0089] The embodiment provides a method for recovering scandium by extraction and washing chloro by organic phase after back extraction, which is different from the embodiment 1 in that the number of stages of countercurrent extraction in step (1) is 4, and the rest of the preparation method and parameters are consistent with the embodiment 1.

[0090] Embodiment 9

[0091] The embodiment provides a method for recovering scandium by extraction and washing chloro by organic phase after back extraction, which is different from the embodiment 1 in that the flow rate of MHP once washing residue water in step (1) is 680L / h, and the flow rate of N1923 extractant solution is 130L / h, and the rest of the preparation method and parameters are consistent with the embodiment 1.

[0092] Embodiment 10

[0093] The embodiment provides a method for recovering scandium by extraction and washing chloro by organic phase after back extraction, which is different from the embodiment 1 in that the flow rate of scandium-loaded organic phase in step (3) is 130L / h, and the flow rate of hydrochloric acid is 40L / h, and the rest of the preparation method and parameters are consistent with the embodiment 1.

[0094] Embodiment 11

[0095] The embodiment provides a method for recovering scandium by extraction and washing chloro by organic phase after back extraction, which is different from the embodiment 1 in that the flow rate of scandium-loaded organic phase in step (4) is 130L / h, and the flow rate of sodium carbonate is 35L / h, and the rest of the preparation method and parameters are consistent with the embodiment 1.

[0096] Comparative Example 1

[0097] The comparative example provides a method for recovering scandium by extraction and washing chlorine after stripping of the organic phase, which is different from example 1 in that the concentration of sodium carbonate in step (4) is 1.8N, and the rest of the preparation method and parameters remain the same as example 1.

[0098] Comparative example 2

[0099] The comparative example provides a method for recovering scandium by extraction and washing chlorine after stripping of the organic phase, which is different from example 1 in that the concentration of sodium carbonate in step (4) is 0.2N, and the rest of the preparation method and parameters remain the same as example 1.

[0100] The scandium content in the scandium-loaded organic phase obtained in examples 1-11 and comparative examples 1-2 is determined, the scandium extraction rate is calculated, the scandium content in the scandium-containing stripping solution is determined, the scandium enrichment amount is calculated, and the chloride ion content in the regenerated organic phase is determined, and the chloride removal rate is calculated. The specific test results are shown in Table 1.

[0101] Table 1

[0102] Item Scandium extraction rate (%) Scandium enrichment amount (g / L) Chlorine removal rate (%) Example 1 99.1 14 92.1 Example 2 98.8 11.5 90.7 Example 3 99.5 15 93.7 Example 4 99.3 9.3 87.3 Example 5 98.9 15.3 81.5 Example 6 99.3 13.4 92.4 Example 7 98.9 13.7 88.4 Example 8 99.3 14.1 91.5 Example 9 96.4 15.3 87.5 Example 10 99.2 12.4 84.3 Example 11 99.1 12.1 90.1 Comparative Example 1 99.3 12.8 92.3 Comparative Example 2 98.8 13 78.1

[0103] From the test results, it can be seen that:

[0104] (1) From examples 1 to 3, it can be seen that by optimizing the extraction process and stripping process, the present application realizes the efficient separation of low-concentration scandium from cobalt, nickel, manganese and other elements in the scandium-containing waste liquid, the scandium extraction rate is high, the scandium is highly concentrated in the obtained scandium-containing stripping solution, which greatly improves the scandium recovery efficiency, and then the chloride-containing organic phase after stripping is washed and regenerated with a regenerant having a concentration of 0.5N-1.5N, which can effectively remove the residual chloride ions in the organic phase, improve the stability and extraction efficiency of the extractant, and make the production line run smoothly. Specifically, the scandium extraction rate is 98.8% or more, the scandium enrichment amount is 10g / L or more, and the highest can reach 15g / L, and the chloride removal rate is 90% or more.

[0105] (2) From examples 1, 4 and 5, it can be seen that by further adjusting the concentration of hydrochloric acid in the countercurrent stripping process in step (3) to 2N-4N, scandium can be effectively recovered without introducing excessive chloride ions in the organic phase, and the scandium enrichment amount in the scandium-containing stripping solution is high and conducive to the subsequent regeneration of the organic phase after stripping.

[0106] (3) From Example 1, Example 6 and 11, it can be seen that by further regulating the number of stages of step (4) of washing with chlorine to 4-6 stages, the flow rate of the organic phase after stripping to 100-120 L / h, and the flow rate of the regenerant to 25-30 L / h, the chlorine removal effect and cost can be considered. If the number of stages of washing with chlorine is too high, the chlorine removal rate cannot be greatly improved, but the consumption of regenerant is increased, resulting in increased cost; if the flow rate is too fast during the washing with chlorine process, the washing effect is reduced, and the chlorine ion removal rate is low.

[0107] (4) From Example 1, Example 7 and 10, it can be seen that by further regulating the number of stages of step (3) of countercurrent stripping to 4-6 stages, the flow rate of the loaded scandium organic phase after washing to 100-120 L / h, and the flow rate of hydrochloric acid to 20-30 L / h, the stripping effect and cost can be considered. If the number of stages of countercurrent stripping is too high, the scandium enrichment cannot be significantly improved, but the consumption of stripping agent is increased, resulting in increased cost; if the flow rate is too fast during the stripping process, the scandium enrichment is reduced, and the enrichment of scandium cannot be effectively achieved.

[0108] (5) From Example 1, Example 8 and 9, it can be seen that by further regulating the number of stages of step (1) of countercurrent extraction to 2-3 stages, the flow rate of the scandium-containing waste liquid to 500-600 L / h, and the flow rate of the N1923 extractant solution to 100-120 L / h, the extraction effect and cost can be considered. If the number of stages of extraction is too high, the scandium extraction rate cannot be greatly improved, but the consumption of N1923 extractant solution is increased, resulting in increased cost; if the flow rate is too fast during the extraction process, most of the scandium in the scandium-containing waste liquid cannot be extracted, and the scandium extraction rate is reduced.

[0109] (6) From Example 1 and Comparative Examples 1 and 2, it can be seen that by using a regenerant with a concentration of 0.5-1.5 N, the chlorine ions in the organic phase can be effectively removed, and the stability and extraction capacity of the extractant are significantly improved. If the concentration of the regenerant is too low, the chlorine removal rate is significantly reduced, and long-term operation can cause the organic phase to emulsify, and the stability and extraction efficiency of the extractant are not significantly improved; if the concentration of the regenerant is too high, the consumption of sodium carbonate (regenerant) is increased, but the chlorine removal rate is not significantly increased, resulting in increased cost.

[0110] In summary, the present application realizes high-efficiency separation of low-concentration scandium and cobalt, nickel, manganese and other elements in the scandium-containing waste liquid by optimizing the extraction process and stripping process, the scandium extraction rate is high, the obtained scandium-containing stripping liquid is high in scandium concentration, the scandium recovery efficiency is greatly improved, then the organic phase containing chlorine after stripping is washed and regenerated by using 0.5N-1.5N regenerant, the residual chlorine ions in the organic phase can be effectively removed, the influence on the subsequent half extraction process is avoided, and the stability and extraction efficiency of the extractant are improved, so that the production line can be smoothly operated.

[0111] The applicant declares that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the present application can be easily thought by any person skilled in the art in the technical field, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for recovering scandium by extraction and washing chlorine from the organic phase after stripping, characterized in that: The method comprises the following steps: (1) using a solvent extraction method to perform countercurrent extraction and separation on the scandium-containing waste liquid to obtain a raffinate and a scandium-loaded organic phase; (2) countercurrently washing the scandium-loaded organic phase in step (1) with an acid solution to obtain a washing solution and a washed scandium-loaded organic phase; (3) subjecting the washed scandium-loaded organic phase in step (2) to countercurrent stripping and separation using hydrochloric acid to obtain a scandium-containing stripping solution and a stripped organic phase; (4) Using a regeneration agent with a concentration of 0.5N to 1.5N, the organic phase after stripping in step (3) is subjected to chlorine washing treatment to obtain a regenerated organic phase.

2. The method according to claim 1, characterized in that In the scandium-containing waste liquid of step (1), the scandium concentration is 700 mg / L to 800 mg / L; Preferably, the pH of the scandium-containing waste liquid in step (1) is 0.5-1; Preferably, the scandium-containing waste liquid in step (1) comprises MHP primary slag washing water and / or MHP leachate; Preferably, the solvent used in the solvent extraction method in step (1) includes N1923 extractant solution; Preferably, the N1923 extractant solution comprises N1923 extractant and a solvent; Preferably, the solvent comprises sulfonated kerosene and / or n-dodecane; Preferably, based on the total mass of the N1923 extractant solution being 100 wt%, the content of the N1923 extractant is 10 wt% to 25 wt%; Preferably, based on the total mass of the N1923 extractant solution being 100 wt%, the content of the solvent is 75 wt% to 90 wt%.

3. The method according to any one of claims 1 or 2, characterized in that The number of stages of the countercurrent extraction in step (1) is 2 to 3; Preferably, the temperature of the countercurrent extraction in step (1) is 25°C to 50°C.

4. The method according to claim 2, characterized in that During the countercurrent extraction process in step (1), the flow rate of the scandium-containing waste liquid is 500 L / h to 600 L / h; Preferably, during the countercurrent extraction process in step (1), the flow rate of the N1923 extractant solution is 100 L / h to 120 L / h.

5. The method according to any one of claims 1 to 4, characterized in that The number of stages of the countercurrent washing in step (2) is 4 to 6; Preferably, the temperature of the countercurrent washing in step (2) is 25°C to 50°C; Preferably, the acid solution in step (2) comprises dilute sulfuric acid and / or dilute hydrochloric acid; Preferably, the concentration of the acid solution in step (2) is 1N to 2N.

6. The method according to any one of claims 1 to 5, characterized in that During the countercurrent washing process in step (2), the flow rate of the scandium-loaded organic phase is 100 L / h to 120 L / h; Preferably, during the countercurrent washing process in step (2), the flow rate of the acid solution is 20 L / h to 30 L / h.

7. The method according to any one of claims 1 to 6, characterized in that The number of stages of the countercurrent stripping in step (3) is 4 to 6; Preferably, the temperature of the countercurrent stripping in step (3) is 25° C. to 50° C.; Preferably, the concentration of the hydrochloric acid in step (3) is 2N to 4N.

8. The method according to any one of claims 1 to 7, characterized in that During the countercurrent stripping process in step (3), the flow rate of the washed scandium-loaded organic phase is 100 L / h to 120 L / h; Preferably, during the countercurrent stripping process in step (3), the flow rate of the hydrochloric acid is 20 L / h to 30 L / h.

9. The method according to any one of claims 1 to 8, characterized in that The chlorine washing treatment in step (4) is a countercurrent stripping treatment; Preferably, the number of stages of chlorine washing in step (4) is 4 to 6; Preferably, the temperature of the chlorine washing in step (4) is 25°C to 50°C; Preferably, the regeneration agent in step (4) comprises sodium carbonate and / or sodium hydroxide.

10. The method according to any one of claims 1 to 9, characterized in that During the chlorine washing process in step (4), the flow rate of the organic phase after stripping is 100 L / h to 120 L / h; Preferably, during the chlorine washing process in step (4), the flow rate of the regeneration agent is 25 L / h to 30 L / h.