A high-salt lithium-containing mother liquor treatment method

Abstract

The present application relates to lithium salt production technical field, disclose a kind of high salt lithium-containing mother liquor treatment method, the method includes the following steps: adjusting the pH of mother liquor to 7-11, then adding oxidizing agent, under stirring reaction for a period of time;Add precipitant and continue to stir to carry out reaction, control the pH of mother liquor in 7-11 during reaction;Stirring reaction is placed after precipitation, remove the precipitate by filtration, complete the boron removal treatment of the mother liquor.The method is suitable for boron removal treatment of lithium-containing mother liquor with complex composition and high salt content, especially suitable for boron removal treatment of sodium precipitation mother liquor in lithium extraction process, with high boron removal rate, low lithium content loss, low cost, less impurities introduction, suitable for industrial use.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium salt production, and particularly relates to a high-salt lithium-containing mother liquor treatment method. BACKGROUND

[0002] In the process of preparing lithium salt from spodumene, lithium sulfate completion liquor is obtained through roasting, acidification, slurry preparation leaching, purification, and evaporation concentration. The lithium sulfate completion liquor is used as raw material for lithium carbonate or lithium hydroxide production. For lithium carbonate production, lithium sulfate undergoes a lithium precipitation reaction to obtain lithium carbonate product and lithium precipitation mother liquor. The lithium precipitation mother liquor is neutralized with sulfuric acid and evaporated to obtain anhydrous sodium sulfate and sodium precipitation mother liquor. The sodium precipitation mother liquor contains a high content of lithium, which needs to be recovered, so it will circulate in the system, thereby enriching a large amount of impurities such as boron and complexing agents (EDTA). These impurities will affect the product quality, causing the product quality to decrease, and causing great losses to the production enterprise.

[0003] Due to the special coordination properties of boron and the influence of various factors on the existence form of boron in aqueous solution, there are various boron-oxygen complex anions such as B(OH) 4- , B2O(OH)6 2- , etc. in the aqueous solution of borate under alkaline conditions, thereby enhancing the solubility of borate itself, making it supersaturated, and making it difficult to remove it by conventional chemical precipitation. The supersaturation degree of borate in the above-mentioned sodium precipitation mother liquor is several times the normal solubility.

[0004] However, the common water body boron removal method has poor boron precipitation effect in solutions with high salt (especially high sulfate), and has problems such as large reagent consumption, high cost, use of organic solvents, and easy environmental pollution.

[0005] Therefore, the existing method is not directly applicable to the boron removal treatment of the sodium precipitation mother liquor (containing lithium) in the preparation of lithium salt from spodumene, and there is an urgent need to develop a high-salt lithium-containing mother liquor treatment method to treat the enriched boron and other impurities in the above-mentioned sodium precipitation mother liquor. SUMMARY

[0006] In view of the defects of the above-mentioned prior art, the purpose of the present application is to provide a high-salt lithium-containing mother liquor treatment method, which is suitable for boron removal treatment of lithium-containing mother liquor with complex composition and high salt content, has high boron removal rate, small lithium content loss, low cost, and introduces few impurities, and is suitable for industrial use.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A high-salt lithium-containing mother liquor treatment method, comprising the following steps:

[0009] Step S1, adjust the pH of the mother liquor to 7-11, then add an oxidizing agent, and react for a period of time under stirring;

[0010] Step S2, add a precipitant and continue to react under stirring, and control the pH of the mother liquor to be 7-11 during the reaction;

[0011] Step S3, after stirring and reacting, stand for precipitation, remove the precipitate by filtration, and complete the boron removal treatment of the mother liquor.

[0012] In an embodiment of the present application, the high-salt lithium-containing mother liquor is a sodium-precipitating mother liquor generated in a lithium spodumene mine lithium carbonate production system;

[0013] The temperature of the sodium-precipitating mother liquor is 85-95℃.

[0014] In an embodiment of the present application, the concentration of sulfate ions in the sodium-precipitating mother liquor is 220-380g / L, the concentration of COD is 6-20g / L, and the concentration of boron is 2-10g / L.

[0015] In an embodiment of the present application, the oxidizing agent is hydrogen peroxide;

[0016] The ratio of the amount of hydrogen peroxide added to the amount of substance of total boron in the mother liquor is 1-4:1.

[0017] In an embodiment of the present application, the precipitant is one or more of magnesium oxide, calcium oxide, calcium hydroxide, or magnesium hydroxide.

[0018] In an embodiment of the present application, the precipitant is calcium hydroxide, and the ratio of the amount of calcium hydroxide added to the amount of substance of total boron in the mother liquor is 0.5-2:1.

[0019] In an embodiment of the present application, at least one of the following conditions is further included:

[0020] In the step S1, the stirring reaction time is 20-40min;

[0021] In the step S2, the stirring reaction time is 2-6h;

[0022] In the step S3, the standing precipitation time is 20-40min.

[0023] In an embodiment of the present application, the following is further included:

[0024] Step S4, adjust the pH of the mother liquor after boron removal treatment to be acidic, add iron powder and activated carbon powder, and continue to stir and react for a period of time;

[0025] Step S5, add the oxidizing agent again, and continue to react under stirring;

[0026] Step S6, after stirring the reaction, adjust the pH to alkaline, stand for precipitation, filter, complete the removal of complexing agent treatment of mother liquor.

[0027] In one embodiment of the present application, it further comprises at least one of the following conditions:

[0028] The concentration of the iron powder added to the mother liquor is 10-50 g / L;

[0029] The concentration of the activated carbon powder added to the mother liquor is 2-10 g / L;

[0030] In the step S4, the pH is adjusted to 2-5.

[0031] In the step S6, the pH is adjusted to 9-12.

[0032] In one embodiment of the present application, in the step S5, the oxidizing agent is 30wt% hydrogen peroxide, and the amount of the 30wt% hydrogen peroxide added is 8-28wt% of the mother liquor.

[0033] Compared with the prior art, the present application has the following beneficial effects:

[0034] 1. The high-salt lithium-containing mother liquor treatment method of the present application can effectively reduce the borate species in the solution after adjusting the solution to medium alkalinity (pH 7-11), which is beneficial for subsequent reactions; the addition of an oxidizing agent oxidizes the borate in a single form to peroxoborate, which then reacts with a precipitant to form insoluble impurities and precipitates, thereby removing boron elements from the solution. This method can be used for boron removal treatment of various lithium-containing solutions, especially lithium-containing solutions with complex composition and high salt content (such as sulfate), such as the boron removal treatment of sodium precipitation mother liquor in the lithium extraction process from ore and the boron removal treatment of salt lake brine; this method has high boron removal rate, small lithium content loss, simple process, low cost, is suitable for industrial production, and is safe, environmentally friendly, and has less impurities introduced.

[0035] 2. The sodium precipitation mother liquor generated in the lithium extraction process from ore has a temperature of about 92-93℃, and the method of the present application can directly treat the sodium precipitation mother liquor at high temperature (85-95℃), and the treated mother liquor can be recycled into the lithium extraction process from ore, which has a simple treatment process, does not need to be cooled, and shortens the time.

[0036] 3. The boron removal treatment in this method can be continuously performed with the removal of complexing agents, the original sodium precipitation mother liquor is a strong alkaline solution with pH greater than 14, the mother liquor after boron removal treatment has a medium alkalinity (pH 7-11), and then the removal of complexing agents is continuously performed, which can reduce the amount of acid; and the removal of complexing agents is performed under acidic conditions by adding iron powder and activated carbon to form numerous micro-batteries, which produce nascent ferrous ions (Fe 2+Hydrogen peroxide (H₂O) and hydrogen atoms possess high chemical activity, which to some extent alters the structure and properties of EDTA in the mother liquor, promoting its degradation. Then, hydrogen peroxide can act as a catalyst to further promote the iron-carbon microelectrolysis reaction, while simultaneously... 2+ Under catalysis, a large number of hydroxyl radicals (·OH) are generated, which have strong oxidizing properties and further promote the breaking of carbon-carbon double bonds in EDTA; finally, after the pH is adjusted to alkaline, Fe... 2+ / Fe 3+ The formation of ferrous hydroxide / ferric hydroxide colloidal precipitate acts as a flocculant, adsorbing and coagulating various impurities in the mother liquor until they settle. Simultaneously, activated carbon also plays an adsorption role, rapidly separating the precipitate after treatment. This achieves the goal of quickly and effectively removing complexing agents from the mother liquor and reducing COD. This method is simple, introduces few impurities, is low-cost, and results in minimal lithium content loss. It also exhibits a high removal rate of EDTA (COD) from mother liquors with complex compositions and high salt content. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the boron removal process in the high-salt lithium-containing mother liquor treatment method of the present invention.

[0039] Figure 2 This is a schematic diagram of the process for removing boron and complexing agents in the high-salt lithium-containing mother liquor treatment method of the present invention. Detailed Implementation

[0040] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0041] Example 1

[0042] like Figure 1 As shown, this invention provides a method for treating high-salt lithium-containing mother liquor, which includes the following steps:

[0043] S1. Use dilute sulfuric acid to adjust the pH of the mother liquor to the range of 7-11, or more preferably, to the range of 9-10. Then add an oxidant and stir, and react for a period of time under stirring. The oxidant can be hydrogen peroxide, hypochlorous acid, etc.

[0044] S2, the mother liquor after the reaction in step S1 is added with a precipitant, and the reaction after the addition of the precipitant is continued under stirring, and the pH of the mother liquor in the reaction after the addition of the precipitant is controlled to be in a medium alkaline condition of 7-11 by adding dilute sulfuric acid, that is, the reaction after the addition of the precipitant is always maintained in a medium alkaline condition of 7-11; more preferably, the pH in the reaction process is controlled in the range of 9-10;

[0045] S3, after the stirring reaction in step S2 is completed, a period of time is allowed for precipitation, and then the precipitate is removed by filtration to complete the boron removal treatment of the mother liquor.

[0046] In an embodiment, the method is used to treat the sodium precipitation mother liquor generated in the lithium spodumene ore production lithium carbonate system, that is, the high-salt lithium-containing mother liquor is the sodium precipitation mother liquor. The sodium precipitation mother liquor produced in the lithium spodumene ore production lithium carbonate system has a temperature of about 92-93℃, and the method does not need to cool the sodium precipitation mother liquor when treating the sodium precipitation mother liquor, but directly treats it at a high temperature (about 85-95℃).

[0047] The sodium precipitation mother liquor has a complex composition and a high salt content, and its composition includes sulfate, sodium, potassium, calcium, boron, chlorine, lithium, complexing agent (EDTA), etc., and has a high COD content (the concentration of reacted EDTA). Generally, the concentration of sulfate ions in the sodium precipitation mother liquor to be treated is in the range of 220-380 g / L, the concentration of boron is in the range of 2-10 g / L, the concentration of lithium is in the range of 10-16 g / L, the concentration of sodium is in the range of 100-150 g / L, and the COD is in the range of 6-20 g / L.

[0048] The oxidizing agent is preferably hydrogen peroxide, and the amount of hydrogen peroxide added should be related to the total boron content in the mother liquor; preferably, the ratio of the amount of hydrogen peroxide added to the amount of substance of total boron in the mother liquor is 1-4:1, which can more fully oxidize the borate in the mother liquor to peroxoborate, providing a good basis for the subsequent reaction.

[0049] The precipitant can be one or a combination of magnesium oxide, calcium oxide, calcium hydroxide, or magnesium hydroxide.

[0050] The precipitant is preferably calcium hydroxide, which is more gentle and low in price and easy to obtain. When calcium hydroxide is used as the precipitant for the reaction, the amount of calcium hydroxide added should be controlled to be in the range of 0.5-2:1 relative to the amount of substance of total boron in the mother liquor, which can ensure more sufficient reaction with peroxoborate and other borates in the mother liquor to generate insoluble precipitate, achieving the best boron removal effect.

[0051] During the reaction, the stirring reaction time in step S1 is preferably controlled to be 20-40 min; the stirring reaction time in step S2 is preferably controlled to be 2-6 h; and the standing precipitation time in step S3 is preferably controlled to be 20-40 min. This is more preferable to ensure that the oxidant fully oxidizes the borate; the precipitant fully reacts with the peroxoborate and other substances to form insoluble impurity precipitates; and the insoluble impurity precipitates fully settle down, so that the impurity precipitates can be fully separated out.

[0052] In summary, the high-salt lithium-containing mother liquor treatment method can effectively reduce the types of borate in the solution after adjusting the solution to be moderately alkaline (pH 7-11), which is beneficial to subsequent reactions; the oxidant is added to oxidize the borate in a relatively single form into peroxoborate, which then reacts with the precipitant to form insoluble impurity precipitates, thereby removing boron elements in the solution. The method can be used for boron removal treatment of various lithium-containing solutions, especially lithium-containing solutions with complex components and high salt content (such as sulfate), such as the boron removal treatment of sodium precipitation mother liquor in the lithium extraction process and the boron removal treatment of salt lake brine. The method has high boron removal rate, small lithium content loss, simple process, low cost, and is suitable for industrial production, and is safe, environmentally friendly, and has less impurity introduction.

[0053] The sodium precipitation mother liquor produced in the lithium extraction process has a temperature of about 92-93°C, and the method of the embodiment can directly treat the sodium precipitation mother liquor in a high-temperature (85-95°C) state. After treatment, the treated mother liquor can be recycled into the lithium extraction process, and the treatment process is simple, does not need to be cooled, the time is shortened, and the heat energy loss is reduced.

[0054] Example 2

[0055] As shown in Figure 2 The high-salt lithium-containing mother liquor treatment method provided by the embodiment of the application further includes the following steps on the basis of the high-salt lithium-containing mother liquor treatment method of Example 1:

[0056] S4, a sulfuric acid solution is added to adjust the pH of the mother liquor after the boron removal treatment in Example 1 to be acidic, and then iron powder and activated carbon powder are added, and the stirring reaction is continued for a period of time, and the stirring reaction time is preferably controlled to be 10-40 min;

[0057] S5, after the reaction in step S1, an oxidant is added, and the reaction is continued under stirring, and the reaction time is preferably controlled to be 1-4 h, so that the EDTA complexing agent can be oxidized and degraded into small molecules under the catalysis of Fe 2+

[0058] S6, after the stirring reaction in step S5, a sodium hydroxide tablet is added to adjust the pH of the mother liquor to be alkaline, and then the mother liquor is left to stand for a period of time for precipitation, and the precipitate and the treated mother liquor are recovered by filtration, thereby completing the treatment of the complexing agent in the mother liquor. The treated mother liquor can be recycled into the lithium extraction process for continuous use.​

[0059] When adding iron powder and activated carbon powder, it is preferable to control the concentration of iron powder added to the mother liquor to be 10-50 g / L, and the concentration of activated carbon powder added to the mother liquor to be 2-10 g / L. After adding iron powder and activated carbon powder, continue stirring for 10-40 minutes to ensure that the iron powder and activated carbon powder are fully dispersed.

[0060] In step S4, the pH of the mother liquor is adjusted to acidity, preferably controlled to 2-5, to provide favorable conditions for the subsequent formation of micro galvanic cells by iron powder and activated carbon powder.

[0061] The oxidant is also 30 wt% hydrogen peroxide (same as in Example 1). The amount of 30 wt% hydrogen peroxide added is controlled to be 8-28 wt% of the mother liquor volume, so as to generate sufficient hydroxyl radicals to degrade EDTA.

[0062] After the reaction in step S6 is completed, adjust the pH of the mother liquor to alkaline, preferably to 9-12, and then let it stand for 10-40 minutes to ensure that the precipitate settles completely, thus completing the treatment to remove the complexing agent.

[0063] This method involves continuous boron removal and decomplexing agent removal treatments. The original sodium precipitation mother liquor is a strongly alkaline solution with a pH greater than 14. After boron removal treatment, the mother liquor becomes moderately alkaline (pH 7-11), and then the decomplexing agent removal treatment is performed directly, reducing the amount of acid used. Furthermore, this decomplexing agent removal treatment involves the addition of iron powder and activated carbon under acidic conditions. Due to the electrode potential difference between iron and carbon, numerous micro-galvanic cells are formed, generating nascent ferrous ions (Fe2+). 2+ Hydrogen peroxide (H₂O) and hydrogen atoms possess high chemical activity, which to some extent alters the structure and properties of EDTA in the mother liquor, promoting its degradation. Then, hydrogen peroxide can act as a catalyst to further promote the iron-carbon microelectrolysis reaction, while simultaneously... 2+ Under catalysis, a large number of hydroxyl radicals (·OH) are generated, which have strong oxidizing properties and further promote the breaking of carbon-carbon double bonds in EDTA; finally, after the pH is adjusted to alkaline, Fe... 2+ / Fe 3+ The formation of ferrous hydroxide / ferric hydroxide colloidal precipitate acts as a flocculant, adsorbing and coagulating various impurities in the mother liquor until they settle. Simultaneously, activated carbon also plays an adsorption role, rapidly separating the precipitate after treatment, thus achieving rapid and effective removal of complexing agents from the mother liquor. This method is simple, introduces few impurities, is low-cost, and results in minimal lithium content loss. It also demonstrates a high removal rate of EDTA (COD) from mother liquors with complex compositions and high salt content.

[0064] Comparative Example 1

[0065] Take 1 L of high-salt lithium-containing mother liquor (sodium precipitation mother liquor in lithium ore production) in a beaker, add 15 g of precipitant calcium hydroxide according to the boron content (2.20 g / L), and react for 2 h under stirring conditions. Remove the impurities by filtration. The total boron concentration in the initial sodium precipitation mother liquor is 2.20 g / L, and the total boron concentration in the treated filtrate is 2.03 g / L, with an efficiency of only 0.077%.

[0066] Experimental Example 1

[0067] (1) Take 1 L of sodium precipitation mother liquor in a beaker, adjust the pH to 11 with dilute sulfuric acid, add 33 mL of 30 wt% hydrogen peroxide, and stir for 20 min for pretreatment. The initial total boron concentration of the sodium precipitation mother liquor is 2.34 g / L, and the lithium concentration is 10.09 g / L.

[0068] (2) Add 18 g of calcium hydroxide and continue to react for 2 h. The pH of the mother liquor is controlled at about 10 throughout the process by adding dilute sulfuric acid.

[0069] (3) After 30 min of standing and precipitation treatment, remove the precipitate by filtration to complete the boron removal treatment of the sodium precipitation mother liquor.

[0070] After detection, the total boron concentration of the treated sodium precipitation mother liquor is reduced to 0.934 g / L, i.e., the boron removal rate is about 60.09%; the lithium concentration is 10.08 g / L, with a very small decrease.

[0071] Experimental Example 2

[0072] (1) Take 1 L of sodium precipitation mother liquor in a beaker, adjust the pH to 9 with dilute sulfuric acid, add 55 mL of 30 wt% hydrogen peroxide, and stir for 30 min for pretreatment. The initial total boron concentration of the sodium precipitation mother liquor is 2.90 g / L, and the lithium concentration is 12.13 g / L.

[0073] (2) Add 20 g of calcium hydroxide and continue to react for 4 h. The pH of the mother liquor is controlled at about 10 throughout the process by adding dilute sulfuric acid.

[0074] (3) After 30 min of standing and precipitation treatment, remove the precipitate by filtration to complete the boron removal treatment of the sodium precipitation mother liquor.

[0075] After detection, the total boron concentration of the treated sodium precipitation mother liquor is reduced to 1.006 g / L, i.e., the boron removal rate is about 65.31%. The lithium concentration is 12.13 g / L, with almost no decrease.

[0076] Experimental Example 3

[0077] (1) Take 1 L of sodium precipitation mother liquor in a beaker, adjust the pH to 10 with dilute sulfuric acid, add 123 mL of 30 wt% hydrogen peroxide, and stir for 35 min for pretreatment. The initial total boron concentration of the sodium precipitation mother liquor is 6.5 g / L, the lithium concentration is 15.37 g / L, and the COD concentration is 9.793 g / L.

[0078] (2) Add 44.5 g of calcium hydroxide and continue to react for 4 h. The pH of the mother liquor is controlled at about 9 throughout the process by adding dilute sulfuric acid.

[0079] (3) After standing for 35 min, filter out the precipitate to complete the boron removal treatment of the sodium precipitation mother liquor.

[0080] (4) Add sulfuric acid solution to the sodium precipitation mother liquor after boron removal treatment to adjust the pH to 3, add 8 g of activated carbon powder and 30 g of iron powder, and stir for 25 min.

[0081] (5) After stirring, add 120 mL of 30 wt% hydrogen peroxide and continue to stir for 3 h.

[0082] (6) Adjust the pH of the solution to 11 with sodium hydroxide tablets, stir uniformly, and then stand for 30 min for precipitation treatment. After the precipitation is completed, filter to complete the complexing agent (EDTA) removal treatment of the mother liquor, and recover the precipitate and the treated sodium precipitation mother liquor (filtrate).

[0083] After detection, the total boron concentration in the treated sodium precipitation mother liquor is reduced to 1.802 g / L, i.e., the boron removal rate is about 72.28%. The lithium concentration is 15.36 g / L, with a very small decrease. The COD concentration is reduced to 2.48 g / L, i.e., the EDTA removal rate is about 74.68%.

[0084] Experimental Example 4

[0085] (1) Take 1 L of sodium precipitation mother liquor in a beaker, adjust the pH to 10 with dilute sulfuric acid, add 150 mL of 30 wt% hydrogen peroxide, and stir for 35 min for pretreatment. The initial total boron concentration of the sodium precipitation mother liquor is 8.469 g / L, the lithium concentration is 15.16 g / L, and the COD concentration is 13.08 g / L.

[0086] (2) Add 50 g of calcium hydroxide and continue to react for 5 h. The pH of the mother liquor is controlled at about 9.5 throughout the process by adding dilute sulfuric acid.

[0087] (3) After standing for 35 min, filter out the precipitate to complete the boron removal treatment of the sodium precipitation mother liquor.

[0088] (4) Add sulfuric acid solution to the sodium precipitation mother liquor after boron removal treatment to adjust the pH to 4, add 8 g of activated carbon powder and 30 g of iron powder, and stir for 35 min.

[0089] (5) After stirring the reaction, 180 mL of 30 wt% hydrogen peroxide was added, and the reaction was continued for 4 h.

[0090] (6) The pH of the solution was adjusted to 11.5 using sodium hydroxide tablets, and after stirring uniformly, the solution was left to stand for 35 min for precipitation treatment. After the precipitation was completed, the solution was filtered to remove the complexing agent (EDTA), and the precipitate and the treated sodium precipitation mother liquor (filtrate) were recovered.

[0091] After detection, the total boron concentration in the treated sodium precipitation mother liquor was reduced to 2.017 g / L, i.e., the boron removal rate was about 76.18%. The lithium concentration was 15.14 g / L, and the reduction was very small. The COD concentration was reduced to 3.11 g / L, i.e., the removal rate of EDTA was about 76.22%.

Claims

1. A method for treating high-salt lithium-containing mother liquor, characterized in that, Includes the following steps: Step S1: Adjust the pH of the mother liquor to 9-10, then add an oxidant and react for a period of time under stirring; the high-salt lithium-containing mother liquor is the sodium precipitation mother liquor produced in the lithium carbonate production system of spodumene ore; the sodium precipitation mother liquor has a sulfate ion concentration of 220-380 g / L, a COD concentration of 6-20 g / L, a boron concentration of 2-10 g / L, a lithium concentration of 10-16 g / L, and a sodium concentration of 100-150 g / L; the temperature of the sodium precipitation mother liquor is 85-95℃; the oxidant is hydrogen peroxide; Step S2: Add a precipitant and continue stirring to carry out the reaction. During the reaction, control the pH of the mother liquor at 7-11. The precipitant is calcium hydroxide. Step S3: After stirring and reacting, allow the mixture to stand and precipitate, then filter to remove the precipitate, thus completing the boron removal treatment of the mother liquor. Step S4: Adjust the pH of the mother liquor after boron removal treatment to acidic, add iron powder and activated carbon powder, and continue stirring to react for a period of time; The concentration of iron powder added to the mother liquor is 10-50 g / L; the concentration of activated carbon powder added to the mother liquor is 2-10 g / L. In step S5, the oxidant is added again, and the reaction continues under stirring; in step S5, the oxidant is 30 wt% hydrogen peroxide, and the amount of 30 wt% hydrogen peroxide added is 8-28 wt% of the mother liquor; Step S6: After stirring the reaction, adjust the pH to alkaline, let it stand to precipitate, filter, and complete the treatment of removing complexing agent from the mother liquor.

2. The method for treating high-salt lithium-containing mother liquor according to claim 1, characterized in that: The ratio of the amount of hydrogen peroxide added to the total amount of boron in the mother liquor is 1-4:

1.

3. The method for treating high-salt lithium-containing mother liquor according to claim 1, characterized in that, The ratio of the amount of calcium hydroxide added to the total amount of boron in the mother liquor is 0.5-2:

1.

4. The method for treating high-salt lithium-containing mother liquor according to claim 1, characterized in that, It also includes at least one of the following conditions: In step S1, the stirring reaction time is 20-40 min; In step S2, the stirring reaction time is 2-6 hours; In step S3, the settling time is 20-40 minutes.

5. The method for treating high-salt lithium-containing mother liquor according to claim 1, characterized in that, It also includes at least one of the following conditions: In step S4, the pH is adjusted to be acidic to 2-5; In step S6, the pH is adjusted to be alkaline at 9-12.

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