A method for recovering valuable metals from antimony-copper-tin slag

Abstract

This disclosure provides a method for recovering valuable metals from antimony-copper-tin slag. The method includes: slurrying the antimony-copper-tin slag; adding a leaching reagent under alkaline conditions to obtain a leaching mixture; conducting a leaching reaction to obtain a leaching solution containing copper slag and antimony-tin; adding a tin precipitation agent to the antimony-tin leaching solution, mixing to obtain a mixed solution, reacting to obtain a tin-enriched concentrate and an antimony-rich solution; adding an oxidant to the antimony-rich solution to conduct an oxidation reaction to obtain antimony-precipitated slag and a post-precipitation solution; drying the antimony-precipitated slag to obtain sodium antimonate product. The method of this disclosure features a simple process flow, achieving efficient separation and recovery of copper, tin, and antimony through stepwise selective precipitation. The overall metal recovery rate is high, enabling the high-value utilization of valuable elements.

Description

Technical Field

[0001] This disclosure relates to the field of comprehensive utilization of metallurgical resources, and more specifically, to a method for recovering valuable metals from antimony-copper-tin slag. Background Technology

[0002] Non-ferrous metal smelting processes generate a significant amount of smelting slag, such as copper flotation tailings, cyanide tailings, lead smelting slag, and zinc leaching slag. my country produces tens of millions of tons of non-ferrous metal smelting slag annually, representing a valuable secondary resource. This slag is rich in valuable elements such as copper, lead, antimony, bismuth, tin, gold, and silver. However, due to its complex composition and significant variations in the content of different valuable metals, the separation and enrichment of these metals are exceptionally difficult.

[0003] During the copper smelting process, copper anode mud will produce a high-antimony copper-tin slag after rare and precious metals are extracted in the rare and precious metals workshop. Existing technologies mainly treat the antimony-containing copper-tin slag through methods such as vacuum distillation, alkaline leaching, acid leaching and replacement, melting / condensation and additive slag making. Prior art 1 (application number: 202211302187.1, application date: 2022.10.24) discloses a method for separating high gold and silver materials containing copper, antimony, tin, and lead, including the following steps: (1) the material is ball-milled to a particle size of 80 mesh or more; (2) first acid leaching: a mixed solution of hydrogen peroxide and hydrochloric acid is added to the material after ball milling in step (1), the temperature is between 60℃ and 80℃, and the reaction is carried out for 2 to 6 hours. After the reaction is completed, a portion of precipitant is added 1 hour before pressure filtration to precipitate lead and prevent lead chloride from cooling and crystallizing and clogging pipes, valves, and pumps; (3) second acid leaching; (4) first acid replacement; (5) hydrolysis; (6) oxidation; (7) neutralization and tin precipitation; (8) copper replacement. This method recovers metallic antimony, tin, and copper sequentially through two acid leaching, acid replacement, hydrolysis, oxidation, neutralization, and replacement processes. However, the process flow of this method is long and the reagent consumption is large.

[0004] Prior art 2 (application number: 202211615234.8, application date: 2022.12.15) discloses a method for recovering lead, antimony and tin from complex lead-antimony hazardous waste materials, including the following steps: (1) side-blown reduction smelting: complex lead-antimony hazardous waste materials are smelted in a side-blown reduction furnace by adding a certain amount of gangue and reducing coal to obtain an alloy; (2) tin separation: the alloy released from the side-blown reduction furnace is loaded into a stainless steel anode pot and heated and stirred to remove tin; (3) copper separation: the alloy after stirring and removing tin is further cooled, xylose is added and stirred to remove slag, and a lead-antimony alloy with a copper content of less than 0.2% is obtained and cast into a lead-antimony alloy anode plate; (4) electrolytic refining: the lead-antimony anode plate is loaded into a lead electrolytic cell for electrolysis, and refined lead ingots are produced after casting. This method utilizes the difference in melting points between antimony, tin, and copper to separate complex lead-antimony hazardous waste materials by adding salt at 750-800℃ to form slag and obtaining tin slag, and adding xylose at 400℃-500℃ to form slag and obtain copper slag. However, this method relies on continuous high-temperature heating throughout the process, resulting in high energy consumption and high raw material costs. Furthermore, the separation process is prone to physical losses such as smoke, splashing, and sticking to the pot, which can affect the overall metal recovery rate.

[0005] Therefore, the long technical process and low metal recovery rate in the traditional antimony-containing copper-tin slag treatment process have become technical problems that urgently need to be solved in this field. Summary of the Invention

[0006] In view of this, this disclosure provides a method for recovering valuable metals from antimony-copper-tin slag, in order to solve the problems of long technical process and low metal recovery rate in the traditional antimony-containing copper-tin slag treatment process.

[0007] One aspect of this disclosure provides a method for recovering valuable metals from antimony-copper-tin slag, the method comprising:

[0008] Antimony-copper-tin slag is slurried, and a leaching reagent is added under alkaline conditions to obtain a leaching mixture. A leaching reaction occurs, yielding a leaching solution containing copper slag and antimony-tin. The antimony-copper-tin slag comprises antimony, copper, and tin, wherein the mass content of antimony is 20%-30%, the mass content of copper is 8%-16%, and the mass content of tin is 2%-6%. The alkalinity of the alkaline conditions is 140 g / L-180 g / L, and the leaching reagent is sodium hydrosulfide. The liquid-to-solid ratio in the leaching mixture is 5:1 ml / g-8:1 ml / g. The leaching reaction temperature is 70℃-95℃, and the leaching reaction time is 1 h-3 h. The amount of leaching agent added is 1.6 to 2.0 times the theoretical reaction amount of antimony, copper, and tin in the antimony-copper-tin slag.

[0009] A tin immersion agent is added to the antimony-tin leaching solution, mixed, and reacted to obtain a tin-enriched product and an antimony-rich solution. The tin immersion agent is an alkaline calcium-silicon or calcium-aluminum-silicon compound. The concentration of the tin immersion agent in the mixture is 4 g / L-8 g / L. The reaction is carried out under alkaline conditions, with an alkalinity of not less than 80 g / L. The reaction temperature is 50℃-80℃, and the reaction time is 1 h-3 h.

[0010] An oxidant is added to the antimony-rich liquid to induce an oxidation reaction, resulting in antimony slag and a post-antimony slag liquid. The antimony slag is dried to obtain sodium antimonate product. The oxidant is either hydrogen peroxide or oxygen. The amount of oxidant added is 1.2 to 1.5 times the theoretical equivalent of antimony reaction. The oxidation reaction temperature is 30°C to 100°C, and the oxidation reaction time is 4 to 8 hours.

[0011] Optionally, the alkalinity of the alkaline conditions is independently selected from any value among 140 g / L, 150 g / L, 160 g / L, 170 g / L, and 180 g / L, or any range between any two of the above points.

[0012] Optionally, in the leaching mixture, the liquid-to-solid ratio is independently selected from any value among 5:1 ml / g, 6:1 ml / g, 7:1 ml / g, 8:1 ml / g, or any range between any two of the above points.

[0013] Optionally, the amount of leaching agent added is independently selected from any value among 1.6 times, 1.7 times, 1.8 times, 1.9 times, and 2.0 times the theoretical reaction amount of antimony, copper, and tin in the antimony-copper-tin slag, or any range between any two of the above points.

[0014] Optionally, the temperature of the leaching reaction is independently selected from any value among 70°C, 85°C, and 95°C, or any range between any two of the above.

[0015] Optionally, the concentration of the tin immersion agent is independently selected from any value among 4 g / L, 5 g / L, 6 g / L, 7 g / L, and 8 g / L, or any range between any two of the above values.

[0016] Optionally, the temperature of the reaction is independently selected from any value among 50°C, 60°C, 70°C, and 80°C, or any range between any two of the above points.

[0017] Optionally, the amount of oxidant added is independently selected from any value among 1.2, 1.3, 1.4, and 1.5 times the equivalent of the antimony theoretical reaction, or any range between any two of the above points.

[0018] Optionally, the temperature of the oxidation reaction is independently selected from any value among 30°C, 50°C, 70°C, 90°C, and 100°C, or any range between any two of the above.

[0019] Optionally, the tin immersion agent is selected from one of dicalcium silicate, calcium silicate, tricalcium aluminate, calcium feldspar, and hydrated calcium silicate.

[0020] Optionally, the copper-containing slag contains not less than 20% copper, less than 2% antimony, and less than 0.6% tin.

[0021] Optionally, sodium hydroxide is added during the leaching reaction to adjust the alkalinity of the alkaline conditions.

[0022] Optionally, water is added during the leaching reaction to adjust the liquid-solid ratio of the leaching mixture.

[0023] Optionally, the tin concentrate contains not less than 40% tin, less than 0.5% copper, and less than 1% antimony.

[0024] Compared with existing technologies, the method for recovering valuable metals from antimony-copper-tin slag disclosed in this invention achieves at least the following beneficial effects:

[0025] First, the method disclosed herein involves selectively leaching high-antimony copper-tin slag under alkaline conditions using a sulfiding reagent to obtain copper-containing slag and a high-antimony tin-containing solution. Then, a tin-precipitating agent is added to the high-antimony tin-containing solution to selectively precipitate tin, resulting in a tin-enriched product and an antimony-rich solution. Finally, an oxidizing agent is introduced into the antimony-rich solution, and a precipitation reaction is conducted to obtain sodium antimonate. The antimony-precipitated solution is returned to the leaching process for recycling. The copper-containing slag can be further processed as a raw material for copper sulfate production, and the tin-enriched product can be used for further production of tin chemical products. This disclosure achieves the sequential separation of copper, tin, and antimony through a three-step process, resulting in a short process flow. The produced sodium antimonate product can be directly sold, and the tin-enriched product can be used as a raw material for tin smelting to produce refined tin or for preparing tin chemical products such as sodium stannate and tin dioxide. The copper-containing slag, after treatment, can also be used in the production of copper sulfate, demonstrating high resource utilization value.

[0026] Second, in the method disclosed herein, the recovery rates of copper, tin, and antimony throughout the entire process are all greater than 97%, achieving efficient metal recovery.

[0027] Third, in the method disclosed herein, the entire process is carried out in an alkaline environment, which avoids equipment corrosion problems caused by acid leaching and reduces the risk of harmful gas escape.

[0028] Fourth, the method disclosed herein uses mild process conditions and low-cost, readily available industrial chemicals as reagents. The antimony-precipitated solution has few impurities and high alkalinity, and can be recycled back into the leaching process, which can greatly save on the cost of additional liquid alkali.

[0029] Of course, any product implementing this disclosure does not necessarily need to achieve all of the technical effects described above at the same time.

[0030] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0032] Figure 1 This is a flowchart of a method for recovering valuable metals from antimony-copper-tin slag, as disclosed in this publication.

[0033] Figure 2 This is a flowchart of the method for recovering valuable metals from antimony-copper-tin slag according to Embodiment 1 of this disclosure;

[0034] Figure 3 This is a flowchart of the method for recovering valuable metals from antimony-copper-tin slag according to Embodiment 2 of this disclosure;

[0035] Figure 4 This is a flowchart of the method for recovering valuable metals from antimony-copper-tin slag according to Embodiment 3 of this disclosure. Detailed Implementation

[0036] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0037] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0038] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0039] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0040] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0041] For the high-antimony copper-tin slag generated after the extraction of rare and precious metals from copper anode mud in the rare and precious metals workshop, existing technologies mainly treat the antimony-containing copper-tin slag through methods such as vacuum distillation, alkaline leaching, acid leaching and replacement, melting / condensation, and additive slag formation. However, traditional antimony-containing copper-tin slag treatment technologies have long processes, low resource utilization levels, and low metal recovery rates. Therefore, there is an urgent need to develop an economical and efficient method for separating and recovering antimony, copper, and tin from smelting slag to achieve high-value utilization of these valuable elements.

[0042] To address the challenges of existing technologies, this disclosure aims to provide a method for the stepwise recovery of valuable metals from high-antimony, copper-tin slag, overcoming the shortcomings of current antimony, copper-tin slag treatment processes that are lengthy, have low resource utilization levels, and low metal recovery rates.

[0043] This disclosure provides a method for recovering valuable metals from antimony-copper-tin slag, such as... Figure 1 As shown, it includes the following steps:

[0044] S100: High antimony copper-tin slag (antimony copper-tin slag) is slurried with a small amount of water, and then leached with leaching reagent in an alkaline environment to obtain copper slag and high antimony tin solution; wherein the copper slag contains Cu≥20%, Sb<2%, Sn<0.6%, achieving efficient enrichment of copper.

[0045] In step S100, the leaching reagent is 32% sodium hydrosulfide, and sodium hydroxide (30% liquid alkali) is added to control the alkalinity of the solution to 140g / L-180g / L. Water is then added to control the liquid-solid ratio of the system to 5:1ml / g-8:1ml / g. After the reaction, the mixture is filtered to separate the slag and the liquid, obtaining copper-containing slag and high-antimony tin-containing solution (antimony-tin leaching solution).

[0046] The main chemical reactions that occur in this process are:

[0047] NaHS + NaOH = Na₂S + H₂O;

[0048] NaOH provides a strongly alkaline environment, and the addition of NaHS provides sufficient sulfur to the solution system. 2- Ions; S 2- The following reactions occur with various metal ions in high-antimony copper-tin slag:

[0049] Sb2O3+6Na2S+3H2O=2Na3SbS3+6NaOH;

[0050] SnO2+3Na2S+2H2O=Na2SnS3+4NaOH;

[0051] CuO + Na₂S + H₂O = CuS↓ + 2NaOH.

[0052] S200: Add tin precipitation agent to the high antimony tin-containing solution obtained from S100, react, and separate by pressure filtration to obtain tin-enriched material and antimony-enriched solution;

[0053] In step S200, the tin immersion agent is an alkaline calcium-silicon / calcium-aluminum-silicon substance, selected from one of dicalcium silicate, calcium silicate, tricalcium aluminate, calcium feldspar, hydrated calcium silicate, etc.

[0054] This process allows for the selective precipitation of tin, while antimony is better retained in the solution. The main principle of tin-antimony separation is that alkaline calcium-silicon / calcium-aluminum-silicon substances hydrolyze in the sulfide leaching solution to release Ca. 2+ SiO3 2- The tin and antimony groups react to release hydroxide ions, which increases the alkalinity of the solution. This causes the dissolved thiostannate ions in the solution to break down and transform into insoluble compounds such as calcium stannate and tin hydroxide. Meanwhile, antimony exists stably in the solution as soluble hydroxyantimonate or thioantimonate ions, thus achieving efficient and selective separation of tin and antimony.

[0055] The main chemical reaction formula is:

[0056] SnS3 2- +4OH - →Sn(OH)4↓+3S 2- ;

[0057] Sn(OH)₄+Ca 2+ →CaSnO3↓+H2O+2H + .

[0058] S300: The antimony-rich solution obtained from S200 is oxidized by adding an oxidant to obtain antimony slag and antimony-precipitated liquid. The antimony-precipitated liquid is returned to the tin-antimony leaching process for use. The antimony slag is washed and dried to obtain sodium antimony product.

[0059] In step S300, the main chemical reaction that occurs in this process is (taking oxygen as an example):

[0060] 2Na3SbS3+7O2+2NaOH+5H2O=2NaSb(OH)6↓+3Na2S2O3.

[0061] In step S300, no additional NaOH is needed, as the free alkalinity of the system has already been controlled to a high level. This reaction process is an alkali-consuming reaction, and the pH will decrease as the reaction proceeds. Therefore, the chemical equation appears to show that sodium hydroxide participates in the reaction as a reactant.

[0062] In the method disclosed herein, the copper-containing slag obtained in S100 is oxidized, calcined, and leached with sulfuric acid to obtain a copper sulfate solution, which can be directly fed into a copper sulfate production line for the production of copper sulfate products.

[0063] In the method disclosed herein, the tin concentrate obtained by S200 contains ≥40% tin, <0.5% copper, and <1% Sb. It can be directly returned to the tin smelting system as a tin refining raw material and recovered as metallic tin through reduction smelting. Alternatively, it can be further extracted and prepared as tin chemical products such as sodium stannate and tin dioxide through a hydrometallurgical process.

[0064] In the method disclosed herein, the sodium antimonate obtained by S300 meets the YS-T22 (2010) standard for grade II sodium antimonate;

[0065] In the method disclosed herein, the recovery rates of copper, tin, and antimony throughout the entire process are all greater than 97%.

[0066] Example 1

[0067] Reference Figure 2 The method for recovering valuable metals from antimony-copper-tin slag in this embodiment includes:

[0068] Take 500g (dry weight) of high antimony copper-tin slag from a smelter. The main metal contents are: Sb 24.95wt%, Cu 10.20wt%, Sn 3.70wt%.

[0069] S101. Alkaline sulfide leaching for copper separation: High-antimony copper-tin slag (antimony-copper-tin slag) is slurried with 300 ml of water, and 30% sodium hydroxide is added simultaneously to control the alkalinity of the solution at 160 g / L. A 32% sodium hydrosulfide (NaHS) solution is then added as the leaching reagent. The amount of sodium hydrosulfide added is 1.8 times the theoretical molar amount required for complete reaction based on the antimony, copper, and tin content in the slag. Water is continuously added to control the liquid-to-solid ratio at 6:1 (liquid volume mL: solid mass g). The solution is heated to 85°C and stirred for 2 hours. After the reaction is complete, hot-press filtration is performed to obtain 223.83 g of copper-containing slag and the filtrate (i.e., antimony-tin leaching solution).

[0070] The content of copper slag components is shown in Table 1:

[0071] Table 1

[0072]

[0073] The process achieved a Sb leaching rate of 97.59% and a Sn leaching rate of 98.59%, reducing the copper content in the filtrate to 0.078 g / L, thus realizing the separation and enrichment of copper.

[0074] S200 Selective Tin Deposition: Take the high antimony tin-containing solution obtained from S100, slowly add hydrated calcium silicate to the solution, and control the amount of hydrated calcium silicate added to 8 g / L. Heat the solution to 60℃ and continue stirring for 2 hours. During the reaction, control the alkalinity to not less than 80 g / L. Gradually, precipitate will be formed in the solution. After the reaction is completed, filter while hot to obtain 45.26 g of tin-enriched material and antimony-enriched solution.

[0075] The content of the main components of the tin-enriched material is shown in Table 2.

[0076] Table 2

[0077]

[0078] The process resulted in a tin precipitation rate of 99.55%, reducing the tin concentration in the solution to 0.027 g / L, thus achieving effective separation of tin and antimony. The tin-enriched product contained ≥40% tin, <0.5% copper, and <1% Sb.

[0079] S300 Antimony Recovery by Oxidation Precipitation: The antimony-rich solution obtained from S200 is transferred to a reaction vessel. The solution is heated to 100℃, and then oxygen is introduced into the solution at a rate of 75 mL / min as an oxidant. The reaction is continued with oxygen blowing and stirring for 6 hours (1.2 times the theoretical amount). After the reaction is completed, the gas blowing and heating are stopped, and the solution is allowed to cool naturally to room temperature before pressure filtration. The resulting antimony precipitate is washed and dried to obtain sodium antimonate product. Chemical analysis shows that the product meets the requirements for industrial sodium antimonate products. The antimony content in the liquid after antimony precipitation is 0.068 g / L, and other impurities are low. The antimony precipitation rate reaches 99.83%. The residual alkali in the liquid after antimony precipitation is about 90 g / L, which is returned to the system for recycling.

[0080] The overall copper recovery rate reached 99.54%, the tin recovery rate reached 98.15%, and the antimony recovery rate reached 97.16%.

[0081] Example 2

[0082] Reference Figure 3 The method for recovering valuable metals from antimony-copper-tin slag in this embodiment includes:

[0083] To examine the recovery effect under different conditions, another set of experiments was conducted using the same high-antimony copper-tin slag sample as in Example 1:

[0084] S102. Alkaline sulfidation leaching for copper separation: High-antimony copper-tin slag (antimony-copper-tin slag) was slurried with 300 mL of water, and 30% sodium hydroxide was added simultaneously to control the alkalinity of the solution at 140 g / L. A 32% sodium hydrosulfide (NaHS) solution was then added as the leaching reagent. The amount of sodium hydrosulfide added was twice the theoretical molar amount required for complete reaction based on the antimony, copper, and tin content in the slag. Water was continuously added to control the liquid-to-solid ratio at 8:1 (liquid volume mL: solid mass g). The solution was heated to 85°C and stirred for 2 hours. After the reaction was completed, hot-press filtration was performed to obtain 219.11 g of copper-containing slag and the filtrate (i.e., antimony-tin leaching solution).

[0085] The content of copper slag components is shown in Table 3:

[0086] Table 3

[0087]

[0088] The process achieved a Sb leaching rate of 98.67% and a Sn leaching rate of 99.41%, reducing the copper content in the filtrate to 0.092 g / L, thus realizing the separation and enrichment of copper.

[0089] S202 Selective Tin Deposition: Take the high antimony tin-containing solution obtained from S100, slowly add tricalcium aluminate to the solution, and control the amount of tricalcium aluminate added to 4 g / L. Heat the solution to 80℃, and control the alkalinity to not less than 80 g / L during the reaction process. Continue stirring and react for 2 hours. Gradually, a precipitate will be formed in the solution. After the reaction is completed, filter while hot to obtain 45.25 g of tin-enriched material and antimony-enriched solution.

[0090] The content of the main components of the tin-enriched material is shown in Table 4.

[0091] Table 4

[0092]

[0093] The process resulted in a tin precipitation rate of 98.64%, reducing the tin concentration in the solution to 0.083 g / L. This achieved effective separation of tin and antimony, with the tin-enriched product containing ≥40% tin, <0.5% copper, and <1% Sb.

[0094] S302, Antimony Recovery by Oxidation and Precipitation: The antimony-rich solution obtained from S200 is transferred to a reaction vessel. 148 mL of 30% hydrogen peroxide solution (1.3 times the theoretical volume) is slowly added at 30°C. The mixture is stirred and reacted for 6 hours. After the reaction is complete, it is naturally cooled to room temperature and then filtered. The resulting antimony precipitate is washed and dried to obtain sodium antimonate. Chemical analysis shows that the product meets the requirements for industrial sodium antimonate products. The antimony content in the post-precipitation solution is 0.102 g / L, and other impurities are low. The antimony precipitation rate reaches 99.75%, and the post-precipitation solution is returned to the system for recycling.

[0095] The overall copper recovery rate reached 99.46%, the tin recovery rate reached 98.06%, and the antimony recovery rate reached 98.11%.

[0096] Example 3

[0097] Reference Figure 4 The method for recovering valuable metals from antimony-copper-tin slag in this embodiment includes:

[0098] To examine the recovery effect under different conditions, another set of experiments was conducted using the same high-antimony copper-tin slag sample as in Example 1:

[0099] S103. Alkaline sulfidation leaching for copper separation: High-antimony copper-tin slag (antimony-copper-tin slag) was slurried with 300 mL of water, and 30% sodium hydroxide was added simultaneously to control the alkalinity of the solution at 180 g / L. A 32 wt% sodium hydrosulfide (NaHS) solution was then added as the leaching reagent. The amount of sodium hydrosulfide added was 1.6 times the theoretical molar amount required for complete reaction based on the antimony, copper, and tin content in the slag. Water was continuously added to control the liquid-to-solid ratio at 5:1 (liquid volume mL: solid mass g). The solution was heated to 95°C and stirred for 3 hours. After the reaction was completed, hot-press filtration was performed to obtain 202.42 g of copper-containing slag and the filtrate (i.e., high-antimony tin-containing solution).

[0100] The content of copper slag components is shown in Table 5:

[0101] Table 5

[0102]

[0103] The process achieved a Sb leaching rate of 97.44% and a Sn leaching rate of 97.46%, reducing the copper content in the filtrate to 0.118 g / L, thus realizing the separation and enrichment of copper.

[0104] S203 Selective Tin Deposition: Take the high antimony tin-containing solution obtained from S100, slowly add calcium feldspar to the solution, and control the amount of calcium feldspar added to 6 g / L. Heat the solution to 60℃, and control the alkalinity to not less than 80 g / L during the reaction process. Continue stirring and reacting for 2 hours. Gradually, precipitate will be formed in the solution. After the reaction is completed, filter while hot to obtain 41.08 g of tin-enriched material and antimony-enriched solution.

[0105] The content of the main components of the tin-enriched material is shown in Table 6.

[0106] Table 6

[0107]

[0108] The process resulted in a tin precipitation rate of 99.70%, reducing the tin concentration in the solution to 0.018 g / L, thus achieving effective separation of tin and antimony. The tin-enriched product contained ≥40% tin, <0.5% copper, and <1% Sb.

[0109] S303, Antimony Recovery by Oxidation and Precipitation: The antimony-rich solution obtained from S200 is transferred to a reaction vessel. The solution is heated to 90℃, and then oxygen is introduced into the solution as an oxidant at a flow rate of 140 mL / min. The reaction is continued with stirring for 4 hours (1.5 times the theoretical amount). After the reaction is completed, the gas supply and heating are stopped, and the solution is allowed to cool naturally to room temperature before pressure filtration. The resulting antimony precipitate is washed and dried to obtain sodium antimonate. Chemical analysis shows that the product meets the requirements for industrial sodium antimonate products. The antimony content in the post-precipitation solution is 0.092 g / L, and other impurities are low. The antimony precipitation rate reaches 99.77%. The residual alkali in the post-precipitation solution is approximately 90 g / L, which is returned to the system for recycling.

[0110] The overall copper recovery rate reached 99.31%, the tin recovery rate reached 97.17%, and the antimony recovery rate reached 97.05%.

[0111] As can be seen from the above embodiments, the method for recovering valuable metals from antimony-copper-tin slag provided in this disclosure achieves at least the following beneficial effects:

[0112] 1. In the method disclosed herein, firstly, a sulfiding reagent is used to selectively leach high-antimony copper-tin slag under alkaline conditions to obtain copper-containing slag and high-antimony tin-containing solution; then, a tin-precipitating agent is added to the high-antimony tin-containing solution to selectively precipitate tin, resulting in tin-enriched material and antimony-rich solution; finally, an oxidizing agent is introduced into the antimony-rich solution to obtain sodium antimonate product through a precipitation reaction. The antimony-precipitated solution is returned to the leaching process for recycling. The copper-containing slag can be further processed as a raw material for copper sulfate production, and the tin-enriched material can be used for further production of tin chemical products. This disclosure achieves the sequential separation of copper, tin, and antimony through a three-step method, with a short process flow. The produced sodium antimonate product can be directly sold, and the tin-enriched material can be used as a raw material for tin smelting to produce refined tin or to prepare tin chemical products such as sodium stannate and tin dioxide. The copper-containing slag can also be used for copper sulfate production after treatment, resulting in high resource utilization value of the products.

[0113] 2. In the method disclosed herein, the recovery rates of copper, tin, and antimony throughout the entire process are all greater than 97%, achieving efficient metal recovery. For example, in Example 1, the overall copper recovery rate reaches 99.54%, the total tin recovery rate reaches 98.15%, and the total antimony recovery rate reaches 97.16%; in Example 2, the overall copper recovery rate reaches 99.46%, the total tin recovery rate reaches 98.06%, and the total antimony recovery rate reaches 98.11%; in Example 3, the overall copper recovery rate reaches 99.31%, the total tin recovery rate reaches 97.17%, and the total antimony recovery rate reaches 97.05%.

[0114] 3. In the method disclosed herein, the entire process is carried out in an alkaline environment, which avoids equipment corrosion problems caused by acid leaching and reduces the risk of harmful gas escape.

[0115] 4. The method disclosed herein uses mild process conditions and low-cost, readily available industrial chemicals as reagents. The antimony-precipitated solution has few impurities and high alkalinity, and can be recycled back into the leaching process, which can greatly save the cost of additional liquid alkali.

[0116] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A method for recovering valuable metals from antimony-copper-tin slag, characterized in that, The method includes: Antimony-copper-tin slag is slurried, and a leaching reagent is added under alkaline conditions to obtain a leaching mixture. A leaching reaction occurs, yielding a leaching solution containing copper slag and antimony-tin. The antimony-copper-tin slag comprises antimony, copper, and tin, wherein the mass content of antimony is 20%-30%, the mass content of copper is 8%-16%, and the mass content of tin is 2%-6%. The alkalinity of the alkaline conditions is 140 g / L-180 g / L, and the leaching reagent is sodium hydrosulfide. The liquid-to-solid ratio in the leaching mixture is 5:1 ml / g-8:1 ml / g. The leaching reaction temperature is 70℃-95℃, and the leaching reaction time is 1 h-3 h. The amount of leaching agent added is 1.6 to 2.0 times the theoretical reaction amount of antimony, copper, and tin in the antimony-copper-tin slag. A tin immersion agent is added to the antimony-tin leaching solution, mixed, and reacted to obtain a tin-enriched product and an antimony-rich solution. The tin immersion agent is an alkaline calcium-silicon or calcium-aluminum-silicon compound. The concentration of the tin immersion agent in the mixture is 4 g / L-8 g / L. The reaction is carried out under alkaline conditions, with an alkalinity of not less than 80 g / L. The reaction temperature is 50℃-80℃, and the reaction time is 1 h-3 h. An oxidant is added to the antimony-rich liquid to induce an oxidation reaction, resulting in antimony slag and a post-antimony slag liquid. The antimony slag is dried to obtain sodium antimonate product. The oxidant is either hydrogen peroxide or oxygen. The amount of oxidant added is 1.2 to 1.5 times the theoretical equivalent of antimony reaction. The oxidation reaction temperature is 30°C to 100°C, and the oxidation reaction time is 4 to 8 hours.

2. The method according to claim 1, characterized in that, The tin immersion agent is selected from one of dicalcium silicate, calcium silicate, tricalcium aluminate, calcium feldspar, and hydrated calcium silicate.

3. The method according to claim 1, characterized in that, The copper-containing slag contains not less than 20% copper, less than 2% antimony, and less than 0.6% tin.

4. The method according to claim 1, characterized in that, In the leaching reaction, sodium hydroxide is added to adjust the alkalinity of the alkaline conditions.

5. The method according to claim 1, characterized in that, In the leaching reaction, water is added to adjust the liquid-solid ratio of the leaching mixture.

6. The method according to claim 1, characterized in that, The tin concentrate contains not less than 40% tin, less than 0.5% copper, and less than 1% antimony.

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