Method for recovering Sn and Sb in hydrochloric acid system through extraction method

Abstract

The invention provides a method for recovering Sn and Sb in a hydrochloric acid system through an extraction method, and relates to the field of valuable metal recovery. The method for recovering Sn and Sb in the hydrochloric acid system through the extraction method comprises the following steps of tin extraction treatment, antimony extraction treatment, first reverse extraction treatment and second reverse extraction treatment. According to the method for recovering Sn and Sb in the hydrochloric acid system through the extraction method, selective interference caused by coexistence of multiple valence states of Sn and Sb in the hydrochloric acid system can be avoided, the extraction selectivity of Sn and Sb in the hydrochloric acid system is effectively improved, the recovery effect and recovery efficiency of Sn and Sb are improved, the technological process is simplified, the operation condition requirement is lowered, and the comprehensive treatment cost is reduced; and the method is suitable for industrial-grade large-scale recovery treatment.

Description

Technical Field

[0001] This invention relates to the field of valuable metal recovery, and in particular to an extraction method for recovering Sn and Sb from a hydrochloric acid system. Background Technology

[0002] Tin (Sn) is a silvery-white metal located in Group IV of the fifth period of the periodic table. It is relatively soft and has good ductility. SnCl4, due to its Lewis acidity, is widely used in organic synthesis and catalysis, and is a highly efficient catalyst for esterification and alkylation reactions.

[0003] Antimony (Sb) is located in Group VA of the fifth period of the periodic table. It is brittle, fragile, and non-ductile, but is a relatively stable metal. Under normal temperature conditions, antimony metal can maintain its surface luster and not be oxidized even after being exposed to humid air for a long time. SbCl3 is commonly used as a strong Lewis acid catalyst in organic synthesis.

[0004] Traditional methods for the enrichment and separation of valuable metals in solution, as well as the purification and removal of impurities from solution, include chemical precipitation, hydrolysis, and displacement. Newer separation methods include solvent extraction, ion exchange, and membrane separation. Common methods for extracting specific valuable metals or compounds from solution include chemical displacement, electrolysis, and reduction. Extraction utilizes the difference in solubility of solutes in organic solvents and water, causing the solute in the solution to transfer to the organic solvent, thus separating the organic solvent from the solution. Then, a suitable back-extraction agent is used to back-extract the solute from the loaded organic phase back into the solution, achieving the purpose of recovering, separating, or removing valuable metals or compounds.

[0005] Regarding the separation of antimony in hydrochloric acid systems, existing technologies disclose extraction methods for separating antimony and iron from mixed antimony-iron solutions. This involves converting antimony and iron ions in the acidic solution to lower valences, then selectively extracting antimony into the organic phase based on the difference in extraction properties between the lower-valence antimony and iron ions. The antimony is further converted into antimony sulfide or antimony oxychloride, thus achieving separation of antimony and iron. However, this process requires the addition of reduced iron powder, introducing new impurities and making it unsuitable for the recovery and separation of Sn and Sb from hydrochloric acid systems. Simultaneously, existing technologies also disclose extraction methods for separating antimony and iron from acidic mixed antimony-iron solutions, but the overall antimony recovery rate is low, and the problem of difficulty in separating antimony and iron still exists in the back-extraction solution.

[0006] Furthermore, existing methods for recovering Sn and Sb from hydrochloric acid systems using extraction suffer from poor extraction selectivity when Sn and Sb are in multiple valence states; and also suffer from problems such as low recovery efficiency, high requirements for reaction conditions, cumbersome process operation, and high overall processing cost.

[0007] Based on this, an extraction method for recovering Sn and Sb from hydrochloric acid systems is provided. This method avoids selective interference caused by the coexistence of multiple valence states of Sn and Sb in hydrochloric acid systems, effectively improves the extraction selectivity for Sn and Sb in hydrochloric acid systems, enhances the recovery effect and efficiency of Sn and Sb, simplifies the process flow, reduces operating condition requirements, and lowers overall processing costs. It is suitable for industrial-scale recycling and is a key technical challenge and important development direction that urgently needs to be addressed in this field. Summary of the Invention

[0008] To address the technical problems existing in the prior art, this invention provides an extraction method for recovering Sn and Sb from a hydrochloric acid system. This method avoids selective interference caused by the coexistence of multiple valence states of Sn and Sb in the hydrochloric acid system, effectively improves the extraction selectivity for Sn and Sb in the hydrochloric acid system, enhances the recovery effect and efficiency of Sn and Sb, simplifies the process flow, reduces operating condition requirements, and lowers overall processing costs. It is suitable for industrial-scale recycling and processing.

[0009] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for recovering Sn and Sb from a hydrochloric acid system by extraction includes the following steps: tin extraction treatment, antimony extraction treatment, first back-extraction treatment, and second back-extraction treatment; The method for extracting tin involves mixing a hydrochloric acid solution containing tin and antimony with a tin extractant, followed by tin extraction. After extraction, liquid-liquid separation is performed to obtain a first raffinate and a first loaded organic phase. The tin extractant is a mixture of metal extractant LIX63 and kerosene; The method for antimony extraction is as follows: the concentration of hydrochloric acid in the first raffinate is adjusted to 18-21 wt% to obtain a diluted first raffinate; the diluted first raffinate is mixed evenly with an antimony extractant and then antimony is extracted; after extraction, liquid-liquid separation is performed to obtain a second raffinate and a second loaded organic phase. The antimony extractant is a mixture of trioctylamine and sulfonated kerosene.

[0010] Furthermore, the first back-extraction process involves back-extracting the first loaded organic phase with hydrochloric acid solution; after back-extraction, liquid-liquid separation is performed to obtain the first back-extraction solution, which is then concentrated to obtain a concentrated tin hydrochloride solution. The second back-extraction process involves back-extracting the second loaded organic phase with hydrochloric acid solution; after back-extraction, liquid-liquid separation is performed to obtain the second back-extract, which is then concentrated to obtain antimony hydrochloride concentrate.

[0011] Preferably, in the tin extraction process, the volume ratio of the tin- and antimony-containing hydrochloric acid solution to the tin extractant is 1-3:1; In the antimony extraction process, the volume ratio of the diluted first raffinate to the antimony extractant is 1-3:1.

[0012] Preferably, in the tin extraction process, the extraction temperature is controlled at 10-45℃ and the extraction time is controlled at 10-30 min; In the antimony extraction process, the extraction temperature is controlled at 25-40℃ and the extraction time is 10-30 min.

[0013] Preferably, the volume content of metal extractant LIX63 in the tin extractant is 25-50%; The volume content of trioctylamine in the antimony extractant is 33-50%.

[0014] Preferably, in the tin extraction process, the hydrochloric acid solution containing tin and antimony has a hydrochloric acid concentration of 25-31 wt%, a total tin concentration of 2-6 wt%, and a total antimony concentration of 2-6 wt%.

[0015] Preferably, in the first back-extraction process, the concentration of the hydrochloric acid solution used is 2-2.2 mol / L; The volume ratio of the first loaded organic phase to the hydrochloric acid solution is 10:1-3.

[0016] Preferably, in the first back-extraction process, the back-extraction temperature is controlled at 25-40℃ and the back-extraction time is 10-30 min; The first back-extraction solution is concentrated to 20-25% of its original volume. The organic phase after the first back-extraction treatment is regenerated and recycled as a tin extractant.

[0017] Preferably, in the second back-extraction process, the concentration of the hydrochloric acid solution used is 0.5-0.7 mol / L; The volume ratio of the second loaded organic phase to the hydrochloric acid solution is 10:1-3.

[0018] Preferably, in the second back-extraction process, the back-extraction temperature is controlled at 25-40℃ and the back-extraction time is 10-30 min; The second back-extraction solution is concentrated to 20-25% of its original volume. The organic phase after the second back-extraction treatment is regenerated and recycled as an antimony extractant.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The extraction method of the present invention for recovering Sn and Sb in hydrochloric acid system by optimizing the selection and combination of extractants, and taking advantage of the difference in the extraction properties of tin and antimony, selectively extracts tin and antimony in hydrochloric acid system to organic phase, which significantly improves the recovery efficiency and recovery effect of tin and antimony. Specifically, a mixture of metal extractant LIX63 and kerosene is first used as tin extractant to selectively extract tin in hydrochloric acid system, and antimony remains in aqueous phase (i.e., first raffinate). Then, after diluting the hydrochloric acid concentration to a predetermined level, a mixture of trioctylamine and sulfonated kerosene is used as antimony extractant to selectively extract antimony in the first raffinate. The aforementioned technical means cooperate and work together to avoid selective interference from the coexistence of multiple valence states of Sn and Sb metal in hydrochloric acid system, effectively improve the extraction selectivity of Sn and Sb in hydrochloric acid system, improve the recovery effect and recovery efficiency of Sn and Sb, simplify the process flow, reduce the requirements of operating conditions, reduce the overall processing cost, and are suitable for industrial-scale recovery and processing.

[0020] (2) Through experiments, the extraction method of the present invention for recovering Sn and Sb in hydrochloric acid system was used to treat hydrochloric acid containing tin and antimony. The total recovery rate of tin was 71.4-79.6% and the total recovery rate of antimony was 80.6-83.5%.

[0021] (3) The extraction method of the present invention for recovering Sn and Sb in hydrochloric acid system effectively simplifies the process operation and optimizes the reaction process. It can solve the problems of cumbersome operation and complicated process of existing recovery process. Hydrolysis, phase inversion and other operations are no longer required in the recovery process, thereby improving the overall recovery efficiency.

[0022] (4) The extraction method of the present invention for recovering Sn and Sb in hydrochloric acid system can avoid the introduction of other impurities during the extraction and separation process, effectively solving the problem of introducing new impurities during the separation process in the existing recovery process. The corresponding tin and antimony concentrate can be obtained by first back-extraction and second back-extraction with hydrochloric acid and evaporation and concentration of the back-extraction liquid. Detailed Implementation

[0023] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described. It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, "first," "second," etc., are used to distinguish similar objects and are not used to describe a particular order or sequence. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] This invention provides a method for recovering Sn and Sb from a hydrochloric acid system by extraction, comprising the following steps: tin extraction treatment, antimony extraction treatment, first back-extraction treatment, and second back-extraction treatment.

[0026] The method for extracting tin is as follows: a hydrochloric acid solution containing tin and antimony is mixed with a tin extractant at a liquid-liquid volume ratio of 1-3:1, and stirred evenly at 80-120 rpm before tin extraction is performed; the extraction temperature is controlled at 10-45℃ and the extraction time is 10-30 min; after extraction, liquid-liquid separation is performed to obtain the first raffinate and the first loaded organic phase, which are ready for use.

[0027] In the tin extraction process, the tin extractant is a mixture of metal extractant LIX63 and kerosene, with the volume content of metal extractant LIX63 in the tin extractant being 25-50%. The selection of the tin extractant is based on the inventors' experimental findings that traditional extractants (such as TBP) are prone to protonation and failure under strong acid conditions. Therefore, the inventors specifically formulated a combination of chelating metal extractant LIX63 and kerosene to specifically extract tin. In the tin extractant, metal extractant LIX63 is the main active reagent, while kerosene mainly acts as a diluent.

[0028] In the tin extraction process, the hydrochloric acid solution containing tin and antimony has a hydrochloric acid concentration of 25-31 wt%, a total tin concentration of 2-6 wt%, and a total antimony concentration of 2-6 wt%.

[0029] The method for antimony extraction is as follows: the hydrochloric acid concentration in the first raffinate is diluted to 18-21 wt% with deionized water to obtain a diluted first raffinate; the diluted first raffinate is mixed with antimony extractant at a liquid-liquid volume ratio of 1-3:1, stirred evenly at 80-120 rpm, and then antimony extraction is performed; the extraction temperature is controlled at 25-40℃, and the extraction time is 10-30 min; after extraction, liquid-liquid separation is performed to obtain a second raffinate and a second loaded organic phase, which are ready for use.

[0030] In the antimony extraction process, the antimony extractant is a mixture of trioctylamine and sulfonated kerosene, with the trioctylamine content in the extractant being 33-50% by volume. The antimony extractant is selected based on the principle of reducing Cl- concentration by diluting the hydrochloric acid concentration in the first raffinate to 18-21 wt%. -After competition, antimony extractants with specific compositions were used for effective extraction to improve the antimony extraction rate.

[0031] The first back-extraction process involves taking the first loaded organic phase and back-extracting it with a hydrochloric acid solution of 2-2.2 mol / L. The back-extraction temperature is controlled at 25-40℃ and the back-extraction time is 10-30 min. Tin is transferred to the aqueous phase during the first back-extraction process. After the back-extraction is completed, liquid-liquid separation is performed to obtain the first back-extraction solution and the back-extracted organic phase. The first back-extraction solution is evaporated and concentrated to 20-25% of its original volume to obtain tin hydrochloride concentrate. The back-extracted organic phase is regenerated and recycled as a tin extractant.

[0032] In the first back-extraction process, the volume ratio of the first loaded organic phase to the hydrochloric acid solution is 10:1-3.

[0033] The second back-extraction process involves taking the second loaded organic phase and back-extracting it with a hydrochloric acid solution of 0.5-0.7 mol / L. The back-extraction temperature is controlled at 25-40℃ and the back-extraction time is 10-30 min. Antimony is transferred to the aqueous phase during the second back-extraction process. After the back-extraction is completed, liquid-liquid separation is performed to obtain the second back-extraction solution and the back-extracted organic phase. The second back-extraction solution is evaporated and concentrated to 20-25% of its original volume to obtain a concentrated antimony hydrochloride solution. The back-extracted organic phase is regenerated and recycled as an antimony extractant.

[0034] In the second back-extraction process, the volume ratio of the second supported organic phase to the hydrochloric acid solution is 10:1-3.

[0035] The present invention will be further described below with reference to some specific embodiments.

[0036] Example 1 This embodiment provides an extraction method for recovering Sn and Sb from a hydrochloric acid system, specifically targeting tin- and antimony-containing hydrochloric acid generated during the washing of crude flame retardant materials. The hydrochloric acid contains 29.56 wt% hydrochloric acid, 3.71 wt% total tin (88.6 wt% tetravalent tin), and 4.05 wt% total antimony (79.4 wt% trivalent antimony). This tin- and antimony-containing hydrochloric acid has high recovery value, but selective recovery is challenging.

[0037] The extraction method for recovering Sn and Sb from the hydrochloric acid system is specifically as follows: 1. Tin extraction treatment A hydrochloric acid solution containing tin and antimony was mixed with a tin extractant at a liquid-liquid volume ratio of 1:1 and stirred at 100 rpm until homogeneous before tin extraction. The extraction temperature was controlled at 25°C and the extraction time was 30 min. After extraction, liquid-liquid separation was performed to obtain the first raffinate and the first loaded organic phase, which were then ready for use.

[0038] The tin extractant is a mixture of metal extractant LIX63 and kerosene, with the volume content of metal extractant LIX63 in the tin extractant being 50%.

[0039] 2. Antimony extraction treatment The hydrochloric acid concentration in the first raffinate was diluted to 20 wt% with deionized water to obtain the diluted first raffinate. The diluted first raffinate was mixed with antimony extractant at a liquid-liquid volume ratio of 1:1 and stirred evenly at 100 rpm for antimony extraction. The extraction temperature was controlled at 25℃ and the extraction time was 30 min. After extraction, liquid-liquid separation was performed to obtain the second raffinate and the second loaded organic phase, which were ready for use.

[0040] The antimony extractant is a mixture of trioctylamine and sulfonated kerosene, with the volume content of trioctylamine in the antimony extractant being 50%.

[0041] 3. First back-extraction process The first loaded organic phase was subjected to back-extraction using a 2 mol / L hydrochloric acid solution. The back-extraction temperature was controlled at 25°C and the back-extraction time was 30 min. Tin was transferred to the aqueous phase during the first back-extraction process. After the back-extraction was completed, liquid-liquid separation was performed to obtain the first back-extraction solution and the back-extracted organic phase. The first back-extraction solution was evaporated and concentrated to 20% of its original volume to obtain tin hydrochloride concentrate. The back-extracted organic phase was regenerated and recycled as a tin extractant.

[0042] The volume ratio of the first loaded organic phase to the hydrochloric acid solution is 10:1.

[0043] 4. Second back-extraction process The second loaded organic phase was subjected to back-extraction using a 0.5 mol / L hydrochloric acid solution. The back-extraction temperature was controlled at 25°C and the back-extraction time was 30 min. Antimony was transferred to the aqueous phase during the second back-extraction process. After the back-extraction was completed, liquid-liquid separation was performed to obtain the second back-extraction solution and the back-extracted organic phase. The second back-extraction solution was evaporated and concentrated to 20% of its original volume to obtain a concentrated antimony hydrochloride solution. The back-extracted organic phase was regenerated and recycled as an antimony extractant.

[0044] The volume ratio of the second loaded organic phase to the hydrochloric acid solution is 10:1.

[0045] After treating hydrochloric acid containing tin and antimony using the method of this embodiment, the total recovery rate of tin was 79.6% and the total recovery rate of antimony was 83.5%.

[0046] Example 2 This embodiment provides an extraction method for recovering Sn and Sb from a hydrochloric acid system, specifically targeting tin- and antimony-containing hydrochloric acid generated during the washing of crude flame retardant materials. The hydrochloric acid contains 29.56 wt% hydrochloric acid, 3.71 wt% total tin (88.6 wt% tetravalent tin), and 4.05 wt% total antimony (79.4 wt% trivalent antimony). This tin- and antimony-containing hydrochloric acid has high recovery value, but selective recovery is challenging.

[0047] The extraction method for recovering Sn and Sb from the hydrochloric acid system is specifically as follows: 1. Tin extraction treatment A hydrochloric acid solution containing tin and antimony was mixed with a tin extractant at a liquid-liquid volume ratio of 2:1. After stirring at 100 rpm, the tin was extracted. The extraction temperature was controlled at 15℃ and the extraction time was 15 min. After extraction, liquid-liquid separation was performed to obtain the first raffinate and the first loaded organic phase, which were then ready for use.

[0048] The tin extractant is a mixture of metal extractant LIX63 and kerosene, with the volume content of metal extractant LIX63 in the tin extractant being 25%.

[0049] 2. Antimony extraction treatment The hydrochloric acid concentration in the first raffinate was diluted to 20 wt% with deionized water to obtain the diluted first raffinate. The diluted first raffinate was mixed with antimony extractant at a liquid-liquid volume ratio of 2:1 and stirred evenly at 100 rpm for antimony extraction. The extraction temperature was controlled at 15℃ and the extraction time was 15 min. After extraction, liquid-liquid separation was performed to obtain the second raffinate and the second loaded organic phase, which were ready for use.

[0050] The antimony extractant is a mixture of trioctylamine and sulfonated kerosene, and the volume content of trioctylamine in the antimony extractant is 33%.

[0051] 3. First back-extraction process The first loaded organic phase was subjected to back-extraction using a 2 mol / L hydrochloric acid solution. The back-extraction temperature was controlled at 15℃ and the back-extraction time was 15 min. Tin was transferred to the aqueous phase during the first back-extraction process. After the back-extraction was completed, liquid-liquid separation was performed to obtain the first back-extraction solution and the back-extracted organic phase. The first back-extraction solution was evaporated and concentrated to 20% of its original volume to obtain tin hydrochloride concentrate. The back-extracted organic phase was regenerated and recycled as a tin extractant.

[0052] The volume ratio of the first loaded organic phase to the hydrochloric acid solution is 10:1.

[0053] 4. Second back-extraction process The second loaded organic phase was subjected to back-extraction using a 0.5 mol / L hydrochloric acid solution. The back-extraction temperature was controlled at 15℃ and the back-extraction time was 15 min. Antimony was transferred to the aqueous phase during the second back-extraction process. After the back-extraction was completed, liquid-liquid separation was performed to obtain the second back-extraction solution and the back-extracted organic phase. The second back-extraction solution was evaporated and concentrated to 20% of its original volume to obtain antimony hydrochloride concentrate. The back-extracted organic phase was regenerated and recycled as an antimony extractant.

[0054] The volume ratio of the second loaded organic phase to the hydrochloric acid solution is 10:1.

[0055] After treating hydrochloric acid containing tin and antimony using the method of this embodiment, the total recovery rate of tin was 71.4% and the total recovery rate of antimony was 80.6%.

[0056] Example 3 This embodiment provides an extraction method for recovering Sn and Sb from a hydrochloric acid system, specifically targeting tin- and antimony-containing hydrochloric acid generated during the washing of crude flame retardant materials. The hydrochloric acid contains 29.56 wt% hydrochloric acid, 3.71 wt% total tin (88.6 wt% tetravalent tin), and 4.05 wt% total antimony (79.4 wt% trivalent antimony). This tin- and antimony-containing hydrochloric acid has high recovery value, but selective recovery is challenging.

[0057] The extraction method for recovering Sn and Sb from the hydrochloric acid system is specifically as follows: 1. Tin extraction treatment A hydrochloric acid solution containing tin and antimony was mixed with a tin extractant at a liquid-liquid volume ratio of 3:1. After stirring at 100 rpm, the tin was extracted. The extraction temperature was controlled at 25℃ and the extraction time was 15 min. After extraction, liquid-liquid separation was performed to obtain the first raffinate and the first loaded organic phase, which were then ready for use.

[0058] The tin extractant is a mixture of metal extractant LIX63 and kerosene, with the volume content of metal extractant LIX63 in the tin extractant being 33%.

[0059] 2. Antimony extraction treatment The hydrochloric acid concentration in the first raffinate was diluted to 20 wt% with deionized water to obtain the diluted first raffinate. The diluted first raffinate was mixed with antimony extractant at a liquid-liquid volume ratio of 3:1 and stirred evenly at 100 rpm for antimony extraction. The extraction temperature was controlled at 25℃ and the extraction time was 15 min. After extraction, liquid-liquid separation was performed to obtain the second raffinate and the second loaded organic phase, which were ready for use.

[0060] The antimony extractant is a mixture of trioctylamine and sulfonated kerosene, with the volume content of trioctylamine in the antimony extractant being 50%.

[0061] 3. First back-extraction process The first loaded organic phase was subjected to back-extraction using a 2 mol / L hydrochloric acid solution. The back-extraction temperature was controlled at 25°C and the back-extraction time was 15 min. Tin was transferred to the aqueous phase during the first back-extraction process. After the back-extraction was completed, liquid-liquid separation was performed to obtain the first back-extraction solution and the back-extracted organic phase. The first back-extraction solution was evaporated and concentrated to 20% of its original volume to obtain tin hydrochloride concentrate. The back-extracted organic phase was regenerated and recycled as a tin extractant.

[0062] The volume ratio of the first loaded organic phase to the hydrochloric acid solution is 10:1.

[0063] 4. Second back-extraction process The second loaded organic phase was subjected to back-extraction using a 0.5 mol / L hydrochloric acid solution. The back-extraction temperature was controlled at 25°C and the back-extraction time was 15 min. Antimony was transferred to the aqueous phase during the second back-extraction process. After the back-extraction was completed, liquid-liquid separation was performed to obtain the second back-extraction solution and the back-extracted organic phase. The second back-extraction solution was evaporated and concentrated to 20% of its original volume to obtain a concentrated antimony hydrochloride solution. The back-extracted organic phase was regenerated and recycled as an antimony extractant.

[0064] The volume ratio of the second loaded organic phase to the hydrochloric acid solution is 10:1.

[0065] After treating hydrochloric acid containing tin and antimony using the method of this embodiment, the total recovery rate of tin was 75.6% and the total recovery rate of antimony was 81.9%.

[0066] The specific raw material dosages, process parameters, and recovery performance indicators for the extraction methods used to recover Sn and Sb from hydrochloric acid systems in Examples 1-3 are summarized in the table below:

[0067] Comparative Example 1 Comparative Example 1 adopts the technical solution of Example 1, except that: 1) in the tin extraction process, the tin extractant is a mixture of trioctylphosphine oxide (TOPO) and kerosene, and the volume content of trioctylphosphine oxide (TOPO) in the tin extractant is 50%; 2) in the antimony extraction process, the antimony extractant is a mixture of tributyl phosphate (TBP) and sulfonated kerosene, and the volume content of tributyl phosphate (TBP) in the antimony extractant is 50%.

[0068] After treating hydrochloric acid containing tin and antimony using the method of Comparative Example 1, the total recovery rate of tin was 59.1% and the total recovery rate of antimony was 63.6%.

[0069] It can be seen that, under the same recovery conditions, the traditional extraction method used in Comparative Example 1 could not effectively avoid the selective interference caused by the coexistence of multiple valence states of Sn and Sb metals in the hydrochloric acid system. The extraction selectivity of Sn and Sb in the hydrochloric acid system was reduced, and the recovery rates of tin and antimony were significantly reduced.

[0070] Unless otherwise stated, all percentages used in this invention are mass percentages.

[0071] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for recovering Sn and Sb from a hydrochloric acid system by extraction, characterized in that, The process includes the following steps: tin extraction treatment, antimony extraction treatment, first back-extraction treatment, and second back-extraction treatment; The method for extracting tin involves mixing a hydrochloric acid solution containing tin and antimony with a tin extractant until homogeneous, and then performing the tin extraction process. After extraction, liquid-liquid separation was performed to obtain the first raffinate and the first loaded organic phase; The tin extractant is a mixture of metal extractant LIX63 and kerosene; The method for antimony extraction is as follows: the concentration of hydrochloric acid in the first raffinate is adjusted to 18-21 wt% to obtain a diluted first raffinate; the diluted first raffinate is mixed evenly with an antimony extractant and then antimony is extracted; after extraction, liquid-liquid separation is performed to obtain a second raffinate and a second loaded organic phase. The antimony extractant is a mixture of trioctylamine and sulfonated kerosene.

2. The method for recovering Sn and Sb from a hydrochloric acid system by extraction according to claim 1, characterized in that, The first back-extraction treatment method is to back-extract the first loaded organic phase using hydrochloric acid solution; After back-extraction, liquid-liquid separation is performed to obtain the first back-extraction solution, which is then concentrated to obtain tin hydrochloride concentrate. The second back-extraction method involves back-extracting the second loaded organic phase using a hydrochloric acid solution. After back-extraction, liquid-liquid separation is performed to obtain a second back-extraction solution, which is then concentrated to obtain antimony hydrochloride concentrate.

3. The method for recovering Sn and Sb from a hydrochloric acid system by extraction according to claim 1, characterized in that, In the tin extraction process, the volume ratio of the hydrochloric acid solution containing tin and antimony to the tin extractant is 1-3:1; In the antimony extraction process, the volume ratio of the diluted first raffinate to the antimony extractant is 1-3:

1.

4. The method for recovering Sn and Sb from a hydrochloric acid system by extraction according to claim 1, characterized in that, In the tin extraction process, the extraction temperature is controlled at 10-45℃ and the extraction time is controlled at 10-30 min. In the antimony extraction process, the extraction temperature is controlled at 25-40℃ and the extraction time is 10-30 min.

5. The method for recovering Sn and Sb from a hydrochloric acid system by extraction according to claim 1, characterized in that, The volume content of metal extractant LIX63 in the tin extractant is 25-50%; The volume content of trioctylamine in the antimony extractant is 33-50%.

6. The method for recovering Sn and Sb from a hydrochloric acid system by extraction according to claim 1, characterized in that, In the tin extraction process, the hydrochloric acid solution containing tin and antimony has a hydrochloric acid concentration of 25-31 wt%, a total tin concentration of 2-6 wt%, and a total antimony concentration of 2-6 wt%.

7. The method for recovering Sn and Sb from a hydrochloric acid system by extraction according to claim 2, characterized in that, In the first back-extraction process, the concentration of the hydrochloric acid solution used is 2-2.2 mol / L; The volume ratio of the first loaded organic phase to the hydrochloric acid solution is 10:1-3.

8. The method for recovering Sn and Sb from a hydrochloric acid system by extraction according to claim 2, characterized in that, In the first back-extraction process, the back-extraction temperature is controlled at 25-40℃ and the back-extraction time is 10-30 min; The first back-extraction solution is concentrated to 20-25% of its original volume. The organic phase after the first back-extraction treatment is regenerated and recycled as a tin extractant.

9. The method for recovering Sn and Sb from a hydrochloric acid system by extraction according to claim 2, characterized in that, In the second back-extraction process, the concentration of the hydrochloric acid solution used is 0.5-0.7 mol / L; The volume ratio of the second loaded organic phase to the hydrochloric acid solution is 10:1-3.

10. The method for recovering Sn and Sb from a hydrochloric acid system by extraction according to claim 2, characterized in that, In the second back-extraction process, the back-extraction temperature is controlled at 25-40℃ and the back-extraction time is 10-30 min; The second back-extraction solution is concentrated to 20-25% of its original volume. The organic phase after the second back-extraction treatment is regenerated and recycled as an antimony extractant.

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