Method for removing antimony and tellurium from anode slime by multi-stage pressurization without chlorine

Abstract

The present application relates to the technical field of anode slime treatment, and discloses a method for removing antimony and tellurium from anode slime by multi-stage pressurization and chlorine-free process, which comprises the following steps: S1, anode slime pretreatment, S2, multi-stage pressurization treatment, S3, separation of antimony and tellurium from the anode slime, S4, preparation of sodium antimonate, S5, tail gas treatment, S6, waste liquid treatment, S7, post-treatment. The method is characterized by the following: one-stage pressurized thiourea transformation is used for deep copper removal, and two-stage pressurized sulfuration is used for chlorine-free antimony and tellurium removal. The process flow does not involve chlorine-containing substances, and the pressurized leaching of alkaline medium does not produce substances with strong corrosivity, thereby reducing the damage to the equipment. In the process of removing antimony and tellurium, the harmful substances generated during the reaction can be treated by waste gas and waste liquid treatment, and the by-products, precipitates, incompletely removed heavy metal ions, trace pollutants and the like in the tail liquid can be removed or converted into harmless substances, so that the tail liquid meets the discharge standard and the environmental pollution caused by the tail liquid discharge is reduced.

Description

Technical Field

[0001] This invention relates to the field of anode mud treatment technology, specifically a method for removing antimony and tellurium from anode mud using a multi-stage pressurized, chlorine-free process. Background Technology

[0002] Anode mud is a fine, mud-like substance that falls to the bottom of the electrolytic cell during electrolytic refining. It mainly consists of impurities insoluble in the electrolyte from the crude anode metal and the metal to be refined. It often contains precious and valuable metals and can be recycled as raw material for refining precious metals such as gold and silver.

[0003] A search revealed that patent application number CN201410221865.0 discloses a fully wet pretreatment method for copper anode sludge. This invention first involves hot acid leaching of the copper anode sludge, leaching copper, selenium, silver, barium, and other metals into the solution, while gold, tellurium, tin, platinum, and platinum group metals remain in the leaching residue. The hot acid leaching residue is then subjected to alkaline leaching, enriching tellurium, lead, and arsenic in the solution. The resulting tellurium-separated residue is then subjected to chlorination to separate gold, enriching gold, platinum, and platinum group metals in the solution, while tin and antimony are enriched in the residue. The hot acid leaching solution is diluted with water, enriching copper and selenium in the diluted solution. The resulting precipitate is then dissolved in nitric acid and filtered to obtain barium sulfate residue and silver nitrate solution. This invention eliminates the energy-intensive and polluting sulfation roasting process in traditional copper anode sludge treatment methods. By removing barium through hot acid leaching before gold and silver extraction and recovering it via open-circuit, the amount of copper anode sludge processed is reduced, and the gold and silver recovery rate is increased.

[0004] Current methods for removing rare and precious metals from anode sludge mostly employ acidic chlorination to remove antimony. The high-chloride waste liquid generated during the reaction process is highly corrosive to the equipment. Furthermore, after removing precious metals such as antimony and tellurium, it is not convenient to treat the harmful substances (waste gas and waste liquid) generated during the reaction or treatment process in a harmless manner. Direct discharge would affect the environment. Therefore, we need to propose a multi-stage pressurized chlorine-free method for removing antimony and tellurium from anode sludge. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-stage pressurized, chlorine-free method for removing antimony and tellurium from anode mud. The process involves a first-stage pressurized thiourea conversion for deep copper removal, followed by a second-stage pressurized sulfidation process for chlorine-free antimony and tellurium removal. The entire process is chlorine-free, using alkaline media for pressurized leaching, which avoids the generation of highly corrosive substances and reduces damage to equipment. Furthermore, during the antimony and tellurium removal process, harmful substances generated during the reaction can be treated as waste gas and waste liquid, removing byproducts, precipitates, incompletely removed heavy metal ions, and trace pollutants from the tail liquid, or converting them into harmless substances. This ensures the tail liquid meets emission standards, reducing environmental pollution and addressing the problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for multi-stage pressurized, chloride-free removal of antimony and tellurium from anode mud, comprising the following steps:

[0007] S1. Anode mud pretreatment: Impurities and moisture in the anode mud are removed by drying, crushing and screening to facilitate subsequent processing.

[0008] S2. Multi-stage pressurized treatment: The first stage uses pressurized thiourea transformation for deep copper removal, and the second stage uses pressurized sulfidation to remove antimony and tellurium without chlorine.

[0009] S3. Use separation technology to separate antimony and tellurium from the anode mud and recover other valuable metal components;

[0010] S4. After leaching antimony and tellurium and reducing tellurium, sodium antimonate is produced from the tail liquid. The remaining solution is the waste liquid.

[0011] S5. Exhaust gas treatment: In the process of chemical reaction and material processing, unreacted gases, volatile organic compounds, and acidic or alkaline gases are generated. These gases are collected and then introduced into the exhaust gas treatment device for purification.

[0012] S6. Wastewater Treatment: In chemical reactions and material processing, wastewater treatment is carried out on incompletely reacted raw materials, reaction byproducts, dissolved metal ions and impurities to remove trace pollutants from the wastewater.

[0013] S7. Further post-processing is performed on the separated antimony, tellurium, and other metals to bring the antimony and tellurium to the required purity and morphology.

[0014] Preferably, in step S1, the anode mud is crushed into small particles or powder, which can increase the surface area of ​​the anode mud, making the chemical and physical reactions in the subsequent processing more efficient, and exposing the impurities and metal elements inside the anode mud, which is convenient for subsequent extraction and separation.

[0015] Then, the anode mud is screened according to its particle size to ensure the particle size range of the anode mud and improve the uniformity and consistency of subsequent processing steps.

[0016] Preferably, in step S2, the process of deep copper removal by pressure thiourea conversion is as follows: copper electrolyte with thiourea additive at a ratio of 0.03% by weight is used to perform a first-stage pressure conversion leaching on the copper-nickel anode mud removed by thickener, selectively removing copper and some tellurium. After the tellurium is separated from the leaching solution after the first-stage pressure conversion leaching, it enters the copper electrolysis production system. The slag after the first-stage pressure conversion leaching is sent to the second-stage pressure sulfidation leaching.

[0017] The process of two-stage pressure sulfidation for the removal of antimony and tellurium without chlorine is as follows: the residue after the first-stage pressure transformation leaching is subjected to sulfidation leaching under alkaline conditions to selectively leach antimony and tellurium. The residue after the second-stage pressure sulfidation leaching is used as a high-quality raw material for the extraction of rare and precious metals. The leachate after the second-stage pressure sulfidation leaching is selectively reduced to crude tellurium powder by acidic sulfur dioxide flue gas. The tail liquid after reduction is used to produce sodium antimonate.

[0018] Preferably, in step S3, antimony and tellurium are separated by precipitation and filtration. By adding a precipitant to the leachate and controlling the pH and temperature conditions of the leachate, antimony and tellurium are precipitated from the solution as precipitates. Then, the precipitates of antimony and tellurium are separated from the leachate by a filter press or a vacuum filter. The filtration operation is repeated multiple times to fully filter out antimony and tellurium.

[0019] For the recovery of other valuable metal components: the leachate after antimony and tellurium are filtered out by distillation to separate the volatile metal components. The leachate is then heated to convert the volatile metal components into vapor, which is then collected by condensation to achieve the separation of the metal components.

[0020] Preferably, in step S4, sodium nitrate is added to the purified tail liquid from step S3. Sodium nitrate reacts with antimony ions in the tail liquid to form insoluble antimonate. After the antimonate is completely precipitated, it is collected by filtration, washed to remove surface impurities, and then dried. Finally, the dried antimonate is reacted with sodium hydroxide solution or sodium carbonate solution to form sodium antimonate, which is then separated from the solution by filtration.

[0021] Preferably, in step S5, the exhaust gas treatment method can be any one of chemical adsorption, physical adsorption, or catalytic conversion, wherein:

[0022] Chemical adsorption: This process involves a chemical reaction between harmful substances in exhaust gas and an absorbent, converting them into harmless gases.

[0023] Physical adsorption: This method uses adsorbents to adsorb harmful substances in exhaust gas and separate them from the exhaust gas.

[0024] Catalytic conversion: Using a catalyst, harmful substances in exhaust gas undergo a chemical reaction at low temperatures, transforming them into harmless substances.

[0025] Preferably, in step S6, the treatment of the tail liquid after the preparation of sodium antimonate includes the following process:

[0026] Pretreatment: Suspended solids, by-products, and precipitates are removed from the tail liquid by screening;

[0027] Main treatment: Adsorbing antimony and tellurium heavy metal ions in the waste liquid using activated carbon or ion exchange resin;

[0028] Advanced treatment: using oxidation or biological treatment methods to further remove trace pollutants from wastewater.

[0029] Preferably, in step S7, the post-processing procedure includes:

[0030] Purification process: The separated antimony, tellurium, and other metals are purified by electrolysis or refining to remove residual impurities and improve the purity of the metals.

[0031] Morphological adjustment: Transforming the purified metal into powder, granules, or blocks;

[0032] Quality control: The purity and composition of metals are accurately determined through chemical analysis and spectral analysis.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] This invention employs a process design involving a first-stage pressurized thiourea transformation for deep copper removal and a second-stage pressurized sulfidation process for chlorine-free antimony and tellurium removal. The entire process is free of chlorine-containing substances, utilizing alkaline media for pressurized leaching, which avoids the generation of highly corrosive substances and reduces damage to equipment. Furthermore, during the antimony and tellurium metal removal process, harmful substances generated during the reaction can be treated as waste gas and waste liquid, removing byproducts, precipitates, incompletely removed heavy metal ions, and trace pollutants from the tail liquid, or converting them into harmless substances, ensuring that the tail liquid meets emission standards and reducing environmental pollution from tail liquid discharge. Attached Figure Description

[0035] Figure 1 This is a flowchart of the present invention;

[0036] Figure 2 This is a flowchart of the present invention. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] Please see Figure 1-2 This invention provides a technical solution: a method for removing antimony and tellurium from anode mud using a multi-stage pressurized, chloride-free process, comprising the following steps:

[0040] S1. Anode mud pretreatment: Impurities and moisture in the anode mud are removed by drying, crushing and screening to facilitate subsequent processing.

[0041] In step S1, the anode mud is crushed into small particles or powder, which can increase the surface area of ​​the anode mud, making the chemical and physical reactions in the subsequent processing more efficient. It can also break down the agglomerates in the anode mud and expose the impurities and metal elements inside the anode mud, making it easier for subsequent extraction and separation.

[0042] The anode mud is then sieved according to particle size to ensure a consistent particle size range and improve the uniformity and consistency of subsequent processing steps. Sieving also allows for the initial separation of impurities and metal elements in the anode mud based on particle size, laying the foundation for finer separation in the future.

[0043] S2. Multi-stage pressurized treatment: The first stage uses pressurized thiourea transformation for deep copper removal, and the second stage uses pressurized sulfidation to remove antimony and tellurium without chlorine.

[0044] In step S2, the process of deep copper removal by pressure thiourea conversion is as follows: copper electrolyte with thiourea additive at a ratio of 0.03% by weight is used to perform a first-stage pressure conversion leaching on the copper-nickel anode mud removed by thickener, selectively removing copper and some tellurium. After the tellurium is separated from the leaching solution after the first-stage pressure conversion leaching, it enters the copper electrolysis production system. The slag after the first-stage pressure conversion leaching is sent to the second-stage pressure sulfidation leaching.

[0045] In a pressurized thiourea conversion process for deep copper removal, the optimal leaching parameters are: temperature 60℃, reaction time 60 minutes, and thiourea weight ratio of 0.03%.

[0046] At this stage, a copper electrolyte was used, supplemented with a thiourea auxiliary agent at a ratio of 0.03% by weight. The addition of thiourea helps promote copper leaching and assists in the removal of some tellurium. The thickened copper-nickel anode slime was subjected to pressure leaching in this electrolyte, achieving selective removal of copper and some tellurium.

[0047] The two-stage pressure sulfidation process for removing antimony and tellurium without chlorine is as follows: the residue after the first-stage pressure transformation leaching is subjected to sulfidation leaching under alkaline conditions to selectively leach antimony and tellurium. The residue after the second-stage pressure sulfidation leaching (i.e., sulfidation residue, which contains abundant rare and precious metals) is used as a high-quality raw material for extracting rare and precious metals. The leachate after the second-stage pressure sulfidation leaching is selectively reduced to crude tellurium powder by acidic sulfur dioxide flue gas. The tail liquid after reduction is used to produce sodium antimonate.

[0048] In the two-stage pressure sulfidation process for the removal of antimony and tellurium without chlorine, the optimal leaching parameters are: temperature 60℃, reaction time 30 minutes, amount of sulfiding agent used is 1.1 times the amount of antimony and tellurium leached, and liquid-solid ratio 3:1.

[0049] Thiourea, as an effective complexing agent, can undergo a complexation reaction with copper ions under pressure. Thiourea combines with copper ions to form a stable complex, which reduces the solubility of copper in anode mud, thereby achieving copper separation.

[0050] The goal of two-stage pressurized sulfidation for chlorine-free removal of antimony and tellurium is to remove antimony and tellurium from the anode mud. The sulfidation reaction was chosen as the chlorine-free removal method to avoid the generation of harmful chloride emissions.

[0051] Under pressure, a sulfiding agent is introduced to react with antimony and tellurium in the anode mud, forming the corresponding sulfides. No chlorine-containing compounds are used throughout the process, thus avoiding the generation and emission of chlorides and meeting environmental protection requirements.

[0052] Table 1. Composition (%) of the pressure-treated copper removal anode mud in stage 1

[0053]

[0054] Table 2. Composition of the copper removal anode mud in the second stage of pressure treatment (%)

[0055]

[0056] In step S2, the first-stage pressure copper removal rate is greater than 98.1%; the second-stage pressure antimony removal rate is greater than 96.3%; the second-stage pressure tellurium removal rate is greater than 91.2%, the tellurium reduction rate is greater than 99.0%, and the crude tellurium powder grade is greater than 98.5%. The entire process can achieve high sulfide pressure leaching rate, thorough separation, and high crude tellurium grade, which is beneficial for the next refining step.

[0057] S3. Use separation technology to separate antimony and tellurium from the anode mud and recover other valuable metal components;

[0058] In step S3, antimony and tellurium are separated by precipitation and filtration. By adding a precipitant to the leachate and controlling the pH and temperature of the leachate, antimony and tellurium are precipitated from the solution as precipitates. Then, the precipitates of antimony and tellurium are separated from the leachate by a filter press or a vacuum filter. The filtration operation is repeated multiple times to fully filter out antimony and tellurium and improve the purity of antimony and tellurium.

[0059] For the recovery of other valuable metal components: the leachate after antimony and tellurium are filtered out by distillation to separate the volatile metal components. The leachate is then heated to convert the volatile metal components into vapor, which is then collected by condensation to achieve the separation of the metal components.

[0060] The obtained antimony and tellurium compounds need further refining to remove residual impurities.

[0061] S4. After leaching antimony and tellurium and reducing tellurium, sodium antimonate is produced from the tail liquid. The remaining solution is the waste liquid.

[0062] In step S4, sodium nitrate is added to the purified tail liquid from step S3. Sodium nitrate reacts with antimony ions in the tail liquid to form insoluble antimonate. After the antimonate is completely precipitated, it is collected by filtration. The collected antimonate is washed to remove surface impurities and then dried. Finally, the dried antimonate is reacted with sodium hydroxide solution or sodium carbonate solution to form sodium antimonate. The sodium antimonate is then separated from the solution by filtration.

[0063] During the reaction of sodium nitrate with antimony ions, and the reaction of antimonate with sodium hydroxide solution or sodium carbonate solution, thorough stirring is required to promote the rapid formation of antimonate from sodium nitrate and antimony ions, and to promote the rapid formation of sodium antimonate from antimonate with alkaline solution.

[0064] S5. Exhaust gas treatment: In the process of chemical reaction and material processing, unreacted gases, volatile organic compounds, and acidic or alkaline gases are generated. These gases are collected and then introduced into the exhaust gas treatment device for purification.

[0065] In step S5, the exhaust gas treatment method can be any one of chemical adsorption, physical adsorption, or catalytic conversion, wherein:

[0066] Chemical adsorption: This process involves a chemical reaction between harmful substances in exhaust gas and an absorbent, converting them into harmless gases.

[0067] Physical adsorption: This method uses adsorbents to adsorb harmful substances in exhaust gas and separate them from the exhaust gas.

[0068] Catalytic conversion: Using a catalyst, harmful substances in exhaust gas undergo a chemical reaction at low temperatures, transforming them into harmless substances.

[0069] S6. Wastewater Treatment: In chemical reactions and material processing, wastewater treatment is carried out on incompletely reacted raw materials, reaction byproducts, dissolved metal ions and impurities to remove trace pollutants from the wastewater.

[0070] In step S6, the treatment of the tail liquid after the preparation of sodium antimonate includes the following process:

[0071] Pretreatment: Suspended solids, by-products, and precipitates are removed from the tail liquid by screening;

[0072] Main treatment: Adsorbing antimony and tellurium heavy metal ions in the waste liquid using activated carbon or ion exchange resin;

[0073] Advanced treatment: using oxidation or biological treatment methods to further remove trace pollutants from wastewater.

[0074] S7. Further post-processing is performed on the separated antimony, tellurium, and other metals to bring the antimony and tellurium to the required purity and morphology.

[0075] In step S7, the post-processing flow includes:

[0076] Purification process: The separated antimony, tellurium, and other metals are purified by electrolysis or refining to remove residual impurities and improve the purity of the metals.

[0077] Morphological adjustment: Transforming the purified metal into powder, granules, or blocks;

[0078] Quality control: The purity and composition of metals are accurately determined through chemical analysis and spectral analysis.

[0079] Example 2

[0080] The similarities with Example 1 will not be repeated here; the differences are...

[0081] S2. Multi-stage pressurized treatment: The first stage uses pressurized thiourea transformation for deep copper removal, and the second stage uses pressurized sulfidation to remove antimony and tellurium without chlorine.

[0082] In step S2, the process of deep copper removal by pressure thiourea conversion is as follows: copper electrolyte with thiourea additive at a ratio of 0.03% by weight is used to perform a first-stage pressure conversion leaching on the copper-nickel anode mud removed by thickener, selectively removing copper and some tellurium. After the tellurium is separated from the leaching solution after the first-stage pressure conversion leaching, it enters the copper electrolysis production system. The slag after the first-stage pressure conversion leaching is sent to the second-stage pressure sulfidation leaching.

[0083] In a pressurized thiourea conversion process for deep copper removal, the optimal leaching parameters are: temperature 90℃, reaction time 90 minutes, and thiourea weight ratio of 0.03%.

[0084] At this stage, a copper electrolyte was used, supplemented with a thiourea auxiliary agent at a ratio of 0.03% by weight. The addition of thiourea helps promote copper leaching and assists in the removal of some tellurium. The thickened copper-nickel anode slime was subjected to pressure leaching in this electrolyte, achieving selective removal of copper and some tellurium.

[0085] The two-stage pressure sulfidation process for removing antimony and tellurium without chlorine is as follows: the residue after the first-stage pressure transformation leaching is subjected to sulfidation leaching under alkaline conditions to selectively leach antimony and tellurium. The residue after the second-stage pressure sulfidation leaching (i.e., sulfidation residue, which contains abundant rare and precious metals) is used as a high-quality raw material for extracting rare and precious metals. The leachate after the second-stage pressure sulfidation leaching is selectively reduced to crude tellurium powder by acidic sulfur dioxide flue gas. The tail liquid after reduction is used to produce sodium antimonate.

[0086] In the two-stage pressure sulfidation process for the removal of antimony and tellurium without chlorine, the optimal leaching parameters are: temperature 90℃, reaction time 75 minutes, amount of sulfiding agent used is 1.2 times the amount of antimony and tellurium leached, and liquid-solid ratio 4:1.

[0087] Thiourea, as an effective complexing agent, can undergo a complexation reaction with copper ions under pressure. Thiourea combines with copper ions to form a stable complex, which reduces the solubility of copper in anode mud, thereby achieving copper separation.

[0088] The goal of two-stage pressurized sulfidation for chlorine-free removal of antimony and tellurium is to remove antimony and tellurium from the anode mud. The sulfidation reaction was chosen as the chlorine-free removal method to avoid the generation of harmful chloride emissions.

[0089] Under pressure, a sulfiding agent is introduced to react with antimony and tellurium in the anode mud, forming the corresponding sulfides. No chlorine-containing compounds are used throughout the process, thus avoiding the generation and emission of chlorides and meeting environmental protection requirements.

[0090] Table 3. Composition (%) of the pressure-treated copper removal anode mud in stage 1

[0091]

[0092] Table 4. Composition of the copper removal anode mud in the two-stage pressure process (%)

[0093]

[0094] In step S2, the first-stage pressure copper removal rate is greater than 98.3%; the second-stage pressure antimony removal rate is greater than 96.5%; the second-stage pressure tellurium removal rate is greater than 91.4%, the tellurium reduction rate is greater than 99.3%, and the crude tellurium powder grade is greater than 98.7%. The entire process can achieve high sulfide pressure leaching rate, thorough separation, and high crude tellurium grade, which is beneficial for the next refining step.

[0095] Example 3

[0096] The similarities with Embodiment 1 and Embodiment 2 will not be repeated here; the differences are as follows:

[0097] S2. Multi-stage pressurized treatment: The first stage uses pressurized thiourea transformation for deep copper removal, and the second stage uses pressurized sulfidation to remove antimony and tellurium without chlorine.

[0098] In step S2, the process of deep copper removal by pressure thiourea conversion is as follows: copper electrolyte with thiourea additive at a ratio of 0.03% by weight is used to perform a first-stage pressure conversion leaching on the copper-nickel anode mud removed by thickener, selectively removing copper and some tellurium. After the tellurium is separated from the leaching solution after the first-stage pressure conversion leaching, it enters the copper electrolysis production system. The slag after the first-stage pressure conversion leaching is sent to the second-stage pressure sulfidation leaching.

[0099] In a pressurized thiourea conversion process for deep copper removal, the optimal leaching parameters are: temperature 120℃, reaction time 120 minutes, and thiourea weight ratio of 0.03%.

[0100] At this stage, a copper electrolyte was used, supplemented with a thiourea auxiliary agent at a ratio of 0.03% by weight. The addition of thiourea helps promote copper leaching and assists in the removal of some tellurium. The thickened copper-nickel anode slime was subjected to pressure leaching in this electrolyte, achieving selective removal of copper and some tellurium.

[0101] The two-stage pressure sulfidation process for removing antimony and tellurium without chlorine is as follows: the residue after the first-stage pressure transformation leaching is subjected to sulfidation leaching under alkaline conditions to selectively leach antimony and tellurium. The residue after the second-stage pressure sulfidation leaching (i.e., sulfidation residue, which contains abundant rare and precious metals) is used as a high-quality raw material for extracting rare and precious metals. The leachate after the second-stage pressure sulfidation leaching is selectively reduced to crude tellurium powder by acidic sulfur dioxide flue gas. The tail liquid after reduction is used to produce sodium antimonate.

[0102] In the two-stage pressure sulfidation process for the removal of antimony and tellurium without chlorine, the optimal leaching parameters are: temperature 120℃, reaction time 120 minutes, the amount of sulfiding agent used is 1.3 times the amount of antimony and tellurium leached, and the liquid-to-solid ratio is 5:1.

[0103] Thiourea, as an effective complexing agent, can undergo a complexation reaction with copper ions under pressure. Thiourea combines with copper ions to form a stable complex, which reduces the solubility of copper in anode mud, thereby achieving copper separation.

[0104] The goal of two-stage pressurized sulfidation for chlorine-free removal of antimony and tellurium is to remove antimony and tellurium from the anode mud. The sulfidation reaction was chosen as the chlorine-free removal method to avoid the generation of harmful chloride emissions.

[0105] Under pressure, a sulfiding agent is introduced to react with antimony and tellurium in the anode mud, forming the corresponding sulfides. No chlorine-containing compounds are used throughout the process, thus avoiding the generation and emission of chlorides and meeting environmental protection requirements.

[0106] Table 5. Composition (%) of the pressure-treated copper removal anode mud in stage 1

[0107]

[0108] Table 6. Composition of the copper removal anode mud in the second stage of pressure treatment (%)

[0109]

[0110] In step S2, the first-stage pressure copper removal rate is greater than 98.4%; the second-stage pressure antimony removal rate is greater than 96.7%; the second-stage pressure tellurium removal rate is greater than 91.5%, the tellurium reduction rate is greater than 99.4%, and the crude tellurium powder grade is greater than 98.8%. The entire process can achieve high sulfide pressure leaching rate, thorough separation, and high crude tellurium grade, which is beneficial for the next refining step.

[0111] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for removing antimony and tellurium from anode mud using a multi-stage pressurized, chloride-free process, characterized in that: Includes the following steps: S1. Anode mud pretreatment: Impurities and moisture in the anode mud are removed by drying, crushing and screening to facilitate subsequent processing. S2. Multi-stage pressurized treatment: The first stage uses pressurized thiourea transformation for deep copper removal, and the second stage uses pressurized sulfidation to remove antimony and tellurium without chlorine. The process of deep copper removal by pressure thiourea conversion is as follows: copper electrolyte with thiourea additive at a ratio of 0.03% by weight is used to perform a first-stage pressure conversion leaching on the copper-nickel anode mud removed by thickener, selectively removing copper and some tellurium. After the tellurium is separated from the leachate after the first-stage pressure conversion leaching, it enters the copper electrolysis production system. The slag after the first-stage pressure conversion leaching is sent to the second-stage pressure sulfidation leaching. The process of two-stage pressure sulfidation for the removal of antimony and tellurium without chlorine is as follows: the residue after the first-stage pressure transformation leaching is subjected to sulfidation leaching under alkaline conditions to selectively leach antimony and tellurium. The residue after the second-stage pressure sulfidation leaching is used as a high-quality raw material for the extraction of rare and precious metals. The leachate after the second-stage pressure sulfidation leaching is selectively reduced to crude tellurium powder by acidic sulfur dioxide flue gas. The tail liquid after reduction is used to produce sodium antimonate. S3. Use separation technology to separate antimony and tellurium from the anode mud and recover other valuable metal components; S4. After leaching antimony and tellurium and reducing tellurium, sodium antimonate is produced from the tail liquid. The remaining solution is the waste liquid. S5. Exhaust gas treatment: In the process of chemical reaction and material processing, unreacted gases, volatile organic compounds, and acidic or alkaline gases are generated. These gases are collected and then introduced into the exhaust gas treatment device for purification. S6. Wastewater Treatment: In chemical reactions and material processing, wastewater treatment is carried out on incompletely reacted raw materials, reaction byproducts, dissolved metal ions and impurities to remove trace pollutants from the wastewater. S7. Further post-processing is performed on the separated antimony, tellurium, and other metals to bring the antimony and tellurium to the required purity and morphology.

2. The method for multi-stage pressurized, chloride-free removal of antimony and tellurium from anode mud according to claim 1, characterized in that: In step S1, the anode mud is crushed into small particles or powder, which increases the surface area of ​​the anode mud, making the chemical and physical reactions in the subsequent processing more efficient, and exposing the impurities and metal elements inside the anode mud, which facilitates subsequent extraction and separation. Then, the anode mud is screened according to its particle size to ensure the particle size range of the anode mud and improve the uniformity and consistency of subsequent processing steps.

3. The method for multi-stage pressurized, chloride-free removal of antimony and tellurium from anode mud according to claim 1, characterized in that: In step S3, antimony and tellurium are separated by precipitation and filtration. By adding a precipitant to the leachate and controlling the pH and temperature of the leachate, antimony and tellurium are precipitated from the solution as precipitates. The precipitates of antimony and tellurium are then separated from the leachate by a filter press or a vacuum filter. The filtration operation is repeated multiple times to fully filter out antimony and tellurium. For the recovery of other valuable metal components: the leachate after antimony and tellurium are filtered out by distillation to separate the volatile metal components. The leachate is then heated to convert the volatile metal components into vapor, which is then collected by condensation to achieve the separation of the metal components.

4. The method for multi-stage pressurized, chloride-free removal of antimony and tellurium from anode mud according to claim 1, characterized in that: In step S4, sodium nitrate is added to the purified tail liquid from step S3. Sodium nitrate reacts with antimony ions in the tail liquid to form insoluble antimonate. After the antimonate is completely precipitated, it is collected by filtration. The collected antimonate is washed to remove surface impurities and then dried. Finally, the dried antimonate is reacted with sodium hydroxide solution or sodium carbonate solution to form sodium antimonate. The sodium antimonate is then separated from the solution by filtration.

5. The method for multi-stage pressurized, chloride-free removal of antimony and tellurium from anode mud according to claim 1, characterized in that: In step S5, the exhaust gas treatment method can be any one of chemical adsorption, physical adsorption, or catalytic conversion, wherein: Chemical adsorption: This process involves a chemical reaction between harmful substances in exhaust gas and an absorbent, converting them into harmless gases. Physical adsorption: This method uses adsorbents to adsorb harmful substances in exhaust gas and separate them from the exhaust gas. Catalytic conversion: Using a catalyst, harmful substances in exhaust gas undergo a chemical reaction at low temperatures, transforming them into harmless substances.

6. The method for multi-stage pressurized chlorine-free removal of antimony and tellurium from anode mud according to claim 1, characterized in that: In step S6, the treatment of the tail liquid after the preparation of sodium antimonate includes the following process: Pretreatment: Suspended solids, by-products, and precipitates are removed from the tail liquid by screening; Main treatment: Adsorbing antimony and tellurium heavy metal ions in the waste liquid using activated carbon or ion exchange resin; Advanced treatment: using oxidation or biological treatment methods to further remove trace pollutants from wastewater.

7. The method for multi-stage pressurized, chloride-free removal of antimony and tellurium from anode mud according to claim 1, characterized in that: In step S7, the post-processing flow includes: Purification process: The separated antimony, tellurium, and other metals are purified by electrolysis or refining to remove residual impurities and improve the purity of the metals. Morphological adjustment: Transforming the purified metal into powder, granules, or blocks; Quality control: The purity and composition of metals are accurately determined through chemical analysis and spectral analysis.

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