Method for removing arsenic and enriching noble metals from anode slime

Abstract

The application discloses a method for removing arsenic and enriching noble metals from anode slime, and comprises the following steps: mixing ground anode slime with concentrated sulfuric acid, a carbonaceous reducing agent and a chloride salt to form a mixture, performing first roasting on the mixture to convert base metals in the anode slime into soluble salts and convert arsenic-containing phases into diarsenic trioxide; heating the mixture after the first roasting to perform second roasting, so that the diarsenic trioxide is volatilized to obtain calcined sand; and after the calcined sand is treated by acid immersion, filtering to obtain a base metal salt-containing solution and noble metal enrichment; the application can realize efficient volatilization and removal of arsenic in the anode slime, efficient removal of base metals and efficient enrichment of noble metals, wherein the removal rate of arsenic is greater than 98%, the removal rate of base metals is all greater than 90%, and the noble metals in the anode slime are hardly lost, and the application has the advantages of high arsenic removal rate, efficient noble metal enrichment, high recovery rate, simple operation and the like.

Description

Technical Field

[0001] This application belongs to the technical field of non-ferrous metal smelting, and specifically relates to a method for removing arsenic from anode slime and enriching precious metals. Background Art

[0002] Anode slime is an enrichment deposit deposited at the bottom of the anode during the electrolytic refining process of metals, with a dark black mud-like appearance. When the anode of crude metal (such as copper, lead) dissolves under the action of current, the gold, silver, platinum group metals, and rare elements such as selenium and tellurium, which are more chemically stable and insoluble in the electrolyte, will fall off and accumulate. Therefore, anode slime is the main raw material for extracting these scarce strategic resources, and its treatment and recovery constitute a crucial and profitable link in modern metallurgy industry.

[0003] However, the presence of arsenic in anode slime brings difficulties to the subsequent treatment of the solution and the separation of base metals. Moreover, during the pretreatment process, the removal rates of base metals such as copper, nickel, tin, and antimony are relatively low, which will cause a problem of large consumption of reagents for the recovery of precious metals and platinum group metals. Summary of the Invention

[0004] This application aims to provide a method for removing arsenic from anode slime and enriching precious metals, so as to solve the difficulties in separating arsenic in anode slime, the relatively low removal rates of base metals such as copper, nickel, tin, and antimony, and the problem of large consumption of reagents for the recovery of precious metals and platinum group metals, and to achieve the enhanced volatilization and removal of arsenic in anode slime, the efficient separation of base metals, and the efficient enrichment of precious metals.

[0005] To solve the above technical problems, this application is implemented as follows:

[0006] In a first aspect, an embodiment of this application provides a method for removing arsenic from anode slime and enriching precious metals, the method comprising:

[0007] Mix the ground anode slime with concentrated sulfuric acid, a carbonaceous reducing agent, and a chloride salt to form a mixture, and perform a first roasting on the mixture to convert the base metals in the anode slime into soluble salts and the arsenic-containing phases into arsenic trioxide;

[0008] Heat the mixture after the first roasting and perform a second roasting to volatilize the arsenic trioxide and obtain calcine;

[0009] After acid leaching treatment of the calcine, filter to obtain a solution containing base metal salts and a precious metal concentrate;

[0010] Wherein, the base metals at least include copper, nickel, tin, and antimony;

[0011] The precious metals at least include gold, silver, platinum, and palladium.

[0012] Optionally, the mass ratio of the anode mud to the concentrated sulfuric acid is 1:(0.1-1).

[0013] The mass ratio of the anode mud to the carbonaceous reducing agent is 1:(0.05-1).

[0014] The mass ratio of the anode mud to the chloride salt is 1:(0.1-1).

[0015] Optionally, the mass ratio of the anode mud to the concentrated sulfuric acid is 1:(0.2-0.4).

[0016] The mass ratio of the anode mud to the carbonaceous reducing agent is 1:(0.1-0.2).

[0017] The mass ratio of the anode mud to the chloride salt is 1:(0.2-0.5).

[0018] Optionally, the carbonaceous reducing agent is selected from at least one of activated carbon, bituminous coal, coke, and starch.

[0019] Optionally, the chloride salt is selected from at least one of sodium chloride, sodium hypochlorite, sodium chlorate, potassium chloride, potassium hypochlorite, and potassium chlorate.

[0020] Optionally, the temperature of the first roasting is 150℃-400℃, and the roasting time is 0.5h-4h.

[0021] Optionally, the temperature of the second roasting is 400℃-800℃, and the roasting time is 0.5h-6h.

[0022] Optionally, the particle size of the ground anode mud is -200 mesh to -400 mesh.

[0023] Optionally, the acid leaching treatment step includes:

[0024] The calcined sand is mixed with sulfuric acid solution and leached by stirring at 25℃-90℃;

[0025] The stirring and leaching time is 0.5h-4h;

[0026] The concentration of the sulfuric acid solution is 10 g / L to 50 g / L.

[0027] Optionally, the solid-liquid ratio of the calcined sand to the sulfuric acid solution is 1:(2-10)g / mL.

[0028] Beneficial technical effects:

[0029] In the embodiments of this application, a two-stage roasting and acid leaching process effectively solves the problems of difficult arsenic removal and low base metal separation efficiency in anode slime. The first roasting, under the action of concentrated sulfuric acid and chloride salts, converts base metals into soluble salts while simultaneously decomposing the arsenic-containing phase. Then, under the action of a reducing agent, high-valence arsenic is converted into volatile arsenic trioxide. The second roasting, through temperature control, allows for the complete volatilization and removal of arsenic trioxide. Finally, acid leaching and filtration achieve highly efficient separation of the base metal solution from the precious metal concentrate, thereby significantly improving the base metal removal rate, reducing reagent consumption for subsequent precious metal recovery, and laying the foundation for efficient precious metal recovery.

[0030] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0031] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0032] Figure 1 This is a flowchart of the method for removing arsenic from anode mud and enriching precious metals proposed in the embodiments of this application. Detailed Implementation

[0033] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0034] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0035] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0036] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] In related technologies, anode slime is an important "secondary resource" in non-ferrous metal metallurgy. Due to its high content of precious metals such as gold, silver, and platinum group metals, it has become an important raw material for extracting and recovering precious metals, and has high recycling value.

[0038] Copper anode mud is a product obtained during the electrolytic refining of crude copper in copper pyrometallurgical / recycled copper production. The yield is generally 0.2%-1.0% of the electrolytic copper production. Its main components and content ranges are: copper 10%-25%, silver 5%-53%, gold 0.05%-5%, selenium 2%-24%, nickel 0.1%-45%, bismuth 0.9%-7%, lead 0.5%-12%, antimony 0.2%-30%, tin 0.5%-10%, etc.

[0039] Currently, the anode mud treatment processes used in large-scale industrial applications both domestically and internationally are generally classified into pyrometallurgical processes, combined beneficiation and smelting processes, and processes that are either entirely wet or primarily wet.

[0040] (1) The pyrometallurgical process first uses atmospheric or oxygen pressure acid leaching to remove copper. The copper-removed slag is then pyrometallurgically smelted and oxidatively blown to obtain an alloy. After electrolytic refining, silver ingots and silver anode mud are produced. After gold extraction, the gold-extracted liquid is replaced or precipitated to enrich platinum, palladium and other substances, and then carried out the next step of recovery.

[0041] (2) In the wet process, the anode mud is first pretreated by acid leaching to remove impurities. The impurity-removing liquid is used to recover copper, antimony and bismuth. The impurity-removed anode mud is sulfated and roasted in a rotary kiln to distill selenium. The selenium-containing flue gas is absorbed by water to produce crude selenium. The distilled selenium residue is treated by wet leaching processes such as water leaching for copper separation, alkali leaching for tellurium separation, chloride leaching for gold separation and sodium sulfite separation for silver separation to produce crude silver powder and crude gold powder. The crude gold and crude silver are refined by electrolysis to obtain gold ingots and silver ingots. The tellurium separation liquid is sent to the tellurium recovery process. After gold reduction, the liquid is replaced by copper powder to obtain platinum-palladium concentrate, which is then leached, separated and recovered from platinum and palladium.

[0042] (3) The combined beneficiation and smelting process involves low-temperature oxidation roasting and copper and selenium removal from copper anode slime, followed by flotation to obtain silver concentrate. The silver concentrate is then smelted to produce alloyed gold, which is then electrolyzed to obtain gold and silver products. Replacing the precious lead smelting and oxidation refining in the traditional process with flotation can essentially eliminate smoke hazards and improve the direct recovery rate of gold and silver. However, pretreatment is required before flotation, and the tailings contain a relatively high amount of gold and silver.

[0043] However, the study of the embodiments in this application found that the presence of arsenic in the copper anode poses difficulties for subsequent solution treatment and base metal separation. These difficulties mainly include: arsenic is often present in base metal-containing materials during base metal recovery, and these materials are hazardous waste, making disposal and sale very difficult. Existing processes primarily involve reverting all arsenic to the copper pyrometallurgical process after precipitation, removing arsenic from the white flue dust, and then sending it to a qualified company for disposal; or directly transferring all arsenic to a company with hazardous waste disposal qualifications for treatment.

[0044] Secondly, during the pretreatment process, the removal rates of base metals such as copper, nickel, tin, and antimony are relatively low, leading to a large consumption of reagents for the recovery of precious metals and platinum group metals. How to achieve efficient pre-removal of arsenic and efficient separation of base and precious metals, and prepare enriched materials of precious metals, is a major problem in the selection of copper anode mud recovery and treatment processes. Therefore, there is an urgent need to propose a method for enhanced arsenic volatilization removal and efficient enrichment of precious metals from copper anode mud.

[0045] Based on this, embodiments of this application propose a method for removing arsenic from anode mud and enriching precious metals. Figure 1 This is a flowchart of a method for removing arsenic from anode mud and enriching precious metals according to an embodiment of this application. The method includes:

[0046] Step S1: The ground anode mud is mixed with concentrated sulfuric acid, carbonaceous reducing agent and chloride salt to form a mixture. The mixture is then subjected to a first calcination to convert the base metals in the anode mud into soluble salts and the arsenic-containing phase into arsenic trioxide.

[0047] In some embodiments, the particle size of the ground anode mud is -200 mesh to -400 mesh.

[0048] It should be noted that the ground anode mud can pass through a 200-mesh sieve, but not a 400-mesh sieve;

[0049] For example, the particle size of the ground anode mud is -200 mesh, -250 mesh, -300 mesh, -350 mesh, and -400 mesh. In this embodiment of the application, the anode mud is ground in the fineness range of -200 mesh to -400 mesh, which can increase the specific surface area of ​​the material and enable the anode mud particles to achieve full and uniform contact with reactants such as concentrated sulfuric acid and chloride salts.

[0050] In some embodiments, the mass ratio of the anode mud to the concentrated sulfuric acid is 1:(0.1-1).

[0051] The mass ratio of the anode mud to the carbonaceous reducing agent is 1:(0.05-1).

[0052] The mass ratio of the anode mud to the chloride salt is 1:(0.1-1).

[0053] It should be noted that the concentration of concentrated sulfuric acid is 98%. The embodiments of this application use a specific proportion of concentrated sulfuric acid, which can ensure the full decomposition of the complex phases of base metals in the anode mud, converting them into soluble sulfates, such as copper sulfate, ferric sulfate / ferrous sulfate, nickel sulfate, tin sulfate, antimony sulfate, etc.

[0054] In some embodiments, the carbonaceous reducing agent is selected from at least one of activated carbon, bituminous coal, coke, and starch.

[0055] In this embodiment, activated carbon, bituminous coal, coke, or starch are used as carbonaceous reducing agents. Through synergistic effects with concentrated sulfuric acid and chloride salts, they can efficiently reduce stable pentavalent arsenic to a lower valence state during the first roasting. This facilitates the subsequent oxidation of arsenic to volatile arsenic trioxide by chloride salts, thereby significantly improving the arsenic removal efficiency. At the same time, these carbonaceous reducing agents also provide a uniform and powerful reducing atmosphere, thereby promoting the full decomposition of complex base metal phases (such as sulfides and selenides) and their conversion into soluble salts. This helps to solve the problem of low removal rates of base metals such as copper, nickel, tin, and antimony in traditional pretreatment.

[0056] In the embodiments of this application, the active components (such as chlorine gas and hydrogen chloride) generated by the decomposition of chloride salts at high temperatures can also effectively destroy the complex phases of base metals (such as selenides and tellurides), converting them into soluble chlorides or chlorates, thus forming a synergistic effect with the formation of sulfates.

[0057] In some embodiments, the chloride salt is selected from at least one of sodium chloride, sodium hypochlorite, sodium chlorate, potassium chloride, potassium hypochlorite, and potassium chlorate.

[0058] It should be noted that the function of chloride salts at high temperatures is essentially to provide active chlorine species (such as Cl2 and HCl), which can undergo oxidation and chlorination reactions with metals and their compounds. The mechanism and ease with which different chloride salts release active chlorine determine the strength of their oxidizing power.

[0059] Hypochlorites, such as sodium hypochlorite and potassium hypochlorite, are strong oxidizing agents and highly efficient at low temperatures. Hypochlorous acid itself is unstable and readily decomposes upon heating to form atomic oxygen and chlorides. Therefore, it has a dual function: it is both a strong oxidizing agent (through atomic oxygen) and a chlorine source, capable of rapidly oxidizing low-valent arsenic to arsenic trioxide. Simultaneously, it exhibits strong destructive power against base metal sulfides and other phases, with a fast reaction rate.

[0060] Chlorates are strong oxidizing agents and are released in a controlled manner; for example, sodium chlorate and potassium chlorate. When heated, chlorates decompose to produce oxygen and chlorides, providing active chlorine and oxygen stably and efficiently at medium and high temperatures, ensuring that the oxidation and volatilization of arsenic and the decomposition of base metal phases can proceed fully.

[0061] Chlorides have mild oxidizing properties, such as sodium chloride and potassium chloride; their action depends on the acidic environment of the system. In the embodiments of this application, concentrated sulfuric acid provides the acidic environment. It has the lowest cost and the widest availability, and the generation of chlorine gas is relatively slow and stable, making the whole process milder and easier to control, with a relatively low risk of acute corrosion to equipment.

[0062] In summary, the chloride salt in this embodiment decomposes to generate active chlorine components during high-temperature roasting, forming a highly efficient synergistic reaction system with carbonaceous reducing agents and concentrated sulfuric acid. On the one hand, the chloride salt can rapidly oxidize low-valence arsenic pretreated with carbonaceous reducing agents into volatile arsenic trioxide, achieving directional removal of arsenic. On the other hand, the released active chlorine components can effectively destroy the stable phases (such as selenides and tellurides) of base metals such as copper, nickel, tin, and antimony, promoting their conversion into soluble chlorides or chlorates, significantly improving the conversion and removal efficiency of base metals.

[0063] In some embodiments, the mass ratio of the anode mud to the concentrated sulfuric acid is 1:(0.2-0.4).

[0064] The mass ratio of the anode mud to the carbonaceous reducing agent is 1:(0.1-0.2).

[0065] The mass ratio of the anode mud to the chloride salt is 1:(0.2-0.5).

[0066] In some embodiments, the temperature of the first calcination is 150℃-400℃, and the calcination time is 0.5h-4h;

[0067] For example, the temperatures for the first roasting are 200℃, 220℃, 240℃, 260℃, 280℃, 300℃, and 330℃; the roasting times are 2h, 2.5h, 3h, 3.5h, and 4h.

[0068] In this embodiment, the first roasting is performed at a temperature ranging from 150°C to 400°C and maintained for 0.5 to 4 hours. This ensures that concentrated sulfuric acid fully penetrates and disrupts the stable structure of the base metal, effectively converting it into soluble sulfate. Simultaneously, it drives the carbonaceous reducing agent to efficiently reduce pentavalent arsenic to a lower valence state that is easier for subsequent processing. Furthermore, it avoids premature volatilization of arsenic or sintering of the material due to excessively high temperatures. Combined with an appropriate roasting time, this ensures that the complex multiphase chemical reaction proceeds fully and smoothly, improving the removal efficiency of arsenic and base metals and reducing the overall reagent consumption for the final precious metal recovery.

[0069] Step S2: Heat the mixture after the first roasting and perform a second roasting to volatilize the arsenic trioxide and obtain roasted sand;

[0070] In some embodiments, the temperature of the second calcination is 400℃-800℃, and the calcination time is 0.5h-6h.

[0071] For example, the temperature of the second firing is 400℃, 500℃, 600℃, 700℃, or 800℃;

[0072] The roasting times are 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, and 6h.

[0073] In some embodiments, the core components of the calcined sand remaining after the second calcination are highly enriched precious metals (such as gold, platinum, palladium in their elemental state, as well as silver chloride or trace amounts of precious metal selenium / telluride), stable base metal compounds formed during pretreatment (such as lead sulfate, as well as oxides of tin and antimony), etc.

[0074] In this embodiment, a second calcination is performed at a temperature of 400℃-800℃ and maintained for 0.5h-6h. This ensures that the low-boiling-point arsenic trioxide generated in the first calcination escapes rapidly and completely from the gas phase. At the same time, at this higher temperature, the active chlorine component generated by the decomposition of chloride salts can deeply destroy the residual complex phases of base metals (such as stubborn selenides and tellurides), promoting their conversion into soluble salts. The appropriate calcination time ensures that the volatilization and decomposition reactions proceed fully, while avoiding the loss of precious metals due to sintering or volatilization of chlorine caused by excessively high temperature or time. Thus, while significantly improving the arsenic removal rate and base metal conversion rate, it ensures the efficient enrichment and recovery of precious metals, solving the problem of high reagent consumption in traditional methods.

[0075] Step S3: After acid leaching, the calcined sand is filtered to obtain a solution containing base metal salts and a precious metal concentrate;

[0076] The base metals include at least copper, nickel, tin, and antimony;

[0077] The precious metals include at least gold, silver, platinum, and palladium.

[0078] In some embodiments, the acid leaching step includes:

[0079] The calcined sand is mixed with sulfuric acid solution and leached by stirring at 25℃-90℃;

[0080] The stirring and leaching time is 0.5h-4h;

[0081] The concentration of the sulfuric acid solution is 10 g / L to 50 g / L.

[0082] In some embodiments, the temperature for stirring and leaching is 25°C-50°C, and the stirring and leaching time is 0.5h-2h;

[0083] In this embodiment, the calcined sand after the second roasting is leached with sulfuric acid solution under mild conditions of 25℃-90℃ for 0.5h-4h with stirring. This efficiently dissolves the soluble base metal salts (such as sulfates and chlorides of copper, nickel, and antimony) generated by the previous roasting conversion, while ensuring that the chemical integrity of the precious metal enrichment (including elemental gold, platinum, palladium, and stable silver chloride) is preserved, thereby achieving efficient and clean separation of base metals and precious metals.

[0084] In some embodiments, the concentration of the sulfuric acid solution is 10 g / L, 20 g / L, 30 g / L, 40 g / L, or 50 g / L;

[0085] This application uses a low-concentration sulfuric acid solution of 10g / L-50g / L for leaching, which can selectively dissolve soluble base metal salts (such as sulfates and chlorides of copper, nickel, tin, and antimony) generated by two roasting processes (first roasting and second roasting) in a mild acidic environment. At the same time, it effectively inhibits the dissolution and corrosion of precious metal accumulations (especially chemically stable elemental gold, platinum, palladium, and silver chloride). This not only reduces acid consumption but also lowers the cost and difficulty of subsequent waste liquid neutralization treatment.

[0086] In some embodiments, the solid-liquid ratio of the calcined sand to the sulfuric acid solution is 1:(2-10)g / mL.

[0087] For example, the solid-liquid ratio of calcined ore to sulfuric acid solution is 1:2 g / mL, 1:3 g / mL, 1:4 g / mL, 1:5 g / mL, 1:6 g / mL, 1:7 g / mL, 1:8 g / mL, 1:9 g / mL, or 1:10 g / mL;

[0088] In this embodiment, by controlling the solid-liquid ratio of calcined sand to sulfuric acid solution within the range of 1:(2-10) g / mL, the low-concentration sulfuric acid solution can achieve sufficient contact and effective penetration with the calcined sand particles. This provides sufficient solvent volume for the soluble base metal salts (such as sulfates and chlorides of copper, nickel, tin, and antimony) generated in the previous roasting process to promote their rapid dissolution and diffusion, preventing reverse reactions caused by local saturation. At the same time, it maintains suitable slurry fluidity to ensure mixing and mass transfer efficiency.

[0089] In summary, the method for removing arsenic and enriching precious metals from anode mud provided in this application achieves efficient removal of arsenic, efficient separation of base metals, and efficient enrichment of precious metals from anode mud; wherein the arsenic removal rate is >98% and the base metal removal rate is >90%. Moreover, there is almost no loss of precious metals in the anode mud, which has the advantages of high arsenic removal rate, efficient enrichment and recovery of precious metals, and simple operation. It can effectively reduce reagent consumption and production costs in the process of recovering precious metals from anode mud, and has significant environmental and economic benefits, meeting the current requirements of green metallurgy and solid waste resource utilization for clean production.

[0090] In some embodiments, the base metal salt solution can be precipitated by sulfidation to obtain a sulfide concentrate, which can be recycled by pyrometallurgical smelting of copper after being batched.

[0091] For example, the base metal salt solution (mainly sulfate solutions containing copper, nickel, tin, and antimony ions) generated after acid leaching is subjected to sulfidation precipitation treatment by introducing a sulfiding agent (such as sodium sulfide or hydrogen sulfide). This process selectively converts base metal ions in the solution into corresponding sulfide precipitates (such as copper sulfide, nickel sulfide, etc.), forming easily collectable sulfide concentrates. These sulfide concentrates can be used as valuable metallurgical intermediate products and, after appropriate batching, are sent to a copper pyrometallurgical system (such as a copper flash furnace or converter) for unified processing. During the smelting process, these sulfides not only serve as supplementary metal raw materials, but the sulfur element in them also provides some calorific value, achieving efficient recovery of base metals and cascade utilization of energy, forming a sound resource closed loop.

[0092] The precious metal concentrate, after acid leaching and purification, has a highly concentrated value, mainly consisting of elemental or stable compounds of precious metals such as gold, silver, platinum, and palladium (e.g., silver chloride). This precious metal concentrate can be directly transferred to a specialized precious metal refining process. For example, subsequent processing includes:

[0093] Silver-reducing furnace smelting: further separating the small amount of residual base metal and reducing the silver to crude silver.

[0094] Hydrometallurgical refining: Using processes such as chlorination, aqua regia leaching, or cyanide leaching to separate and purify individual precious metals such as gold, platinum, and palladium.

[0095] Electrolytic refining: ultimately producing high-purity precious metal products. Specific steps are not limited in the embodiments of this application.

[0096] To enable those skilled in the art to better understand this application, the following embodiments will be used to provide a detailed description of a method for removing arsenic from anode mud and enriching precious metals provided in this application.

[0097] Example 1

[0098] Example 1 uses copper anode mud from a smelter in Jiangxi Province. The representative sample contains the following valuable components: gold 6495.6 g / t, silver 14.60%, platinum 128.4 g / t, palladium 1005.6 g / t. The base metal content is: copper 20.21%, nickel 8.63%, tin 3.31%, antimony 8.35%, and arsenic 5.51%. The specific steps include:

[0099] (1) First, grind 1 kg of copper anode mud to a particle size of -200 mesh to -400 mesh. Mix the ingredients according to the mass ratio of copper anode mud: concentrated sulfuric acid: activated carbon powder: potassium chloride = 1:0.2:0.05:0.2 and mix them evenly. Place the resulting mixture in a muffle furnace or tube furnace equipped with a dust collection device for roasting. The first roasting condition is roasting at 200℃ for 2 hours.

[0100] (2) After the first roasting, the temperature is raised for a second roasting. The conditions for the second roasting are 500℃ for 3 hours. After the reaction is completed, the arsenic volatilizes to obtain roasted sand.

[0101] (3) The calcined sand is transferred to a stirred leaching reactor for stirred leaching. The concentration of the dilute sulfuric acid solution is 10 g / L, the solid-liquid ratio of the calcined sand to the dilute sulfuric acid solution is 1:5, the leaching temperature is 25℃, and the leaching time is 0.5 h.

[0102] (4) After leaching, solid-liquid separation is carried out to obtain precious metal-enriched material and base metal salt solution.

[0103] Based on the analysis and calculations, in Example 1, the precious metal enriched material obtained after treatment of copper anode mud had a yield of 61%, an arsenic content reduced to 0.18%, and a removal rate of 98.01%.

[0104] Removal rates of base metals: copper 98.2%, nickel 91.3%, tin 90.8%, antimony 92.5%;

[0105] The enrichment factor for precious metals is 1.67.

[0106] Example 2

[0107] Example 2 used copper anode mud from a local smelter. The representative sample contained the following valuable components: gold 6495.6 g / t, silver 14.60%, platinum 128.4 g / t, palladium 1005.6 g / t. The base metal content was: copper 20.21%, nickel 8.63%, tin 3.31%, antimony 8.35%, and arsenic 5.51%. The specific steps included:

[0108] (1) First, grind 1 kg of copper anode mud to a particle size of -200 mesh to -400 mesh. Mix the ingredients according to the mass ratio of copper anode mud: concentrated sulfuric acid: coke powder: sodium chloride = 1:0.3:0.1:0.3 and mix them evenly. Place the resulting mixture in a muffle furnace or tube furnace equipped with a dust collection device for roasting. The first roasting condition is roasting at 250℃ for 3 hours.

[0109] (2) After the first roasting, the temperature was raised for a second roasting. The conditions for the second roasting were 550℃ for 4 hours. After the reaction was completed, calcined sand was obtained.

[0110] (3) The calcined sand is transferred to a stirred leaching reactor for stirred leaching. The concentration of the dilute sulfuric acid solution is 20 g / L, the solid-liquid ratio of the calcined sand to the dilute sulfuric acid solution is 1:4, the leaching temperature is 30℃, and the leaching time is 1 h.

[0111] (4) After leaching, solid-liquid separation is carried out to obtain precious metal-enriched material and base metal salt solution.

[0112] Based on the analysis and calculations, in Example 2, the precious metal enriched material obtained after processing the copper anode mud had a yield of 59%, an arsenic content reduced to 0.15%, and a removal rate of 98.39%.

[0113] Removal rates of base metals: copper 98.4%, nickel 92.1%, tin 91.2%, antimony 93.1%;

[0114] The enrichment factor for precious metals is 1.69.

[0115] Example 3

[0116] Example 3 uses copper anode mud from a smelter in Jiangxi Province. The representative sample contains the following valuable components: gold 6495.6 g / t, silver 14.60%, platinum 128.4 g / t, palladium 1005.6 g / t. The base metal content is: copper 20.21%, nickel 8.63%, tin 3.31%, antimony 8.35%, and arsenic 5.51%. The specific steps include:

[0117] (1) First, grind 1 kg of copper anode mud to a particle size of -200 mesh to -400 mesh. Mix the ingredients according to the mass ratio of copper anode mud: concentrated sulfuric acid: starch: sodium chloride = 1:0.4:0.15:0.4 and mix them evenly. Place the resulting mixture in a muffle furnace or tube furnace equipped with a dust collection device for roasting. The first roasting condition is roasting at 300℃ for 3 hours.

[0118] (2) After the first roasting, the temperature is raised for a second roasting. The roasting conditions are 600℃ for 5 hours. After the reaction is completed, calcined sand is obtained.

[0119] (3) The calcined sand was transferred to a stirred leaching reactor for stirred leaching. The concentration of the dilute sulfuric acid solution was 40 g / L, the solid-liquid ratio of the calcined sand to the dilute sulfuric acid solution was 1:3, the leaching temperature was 40℃, and the leaching time was 1.5 h.

[0120] (4) After leaching, solid-liquid separation is carried out to obtain precious metal-enriched material and base metal salt solution.

[0121] Based on the analysis and calculation results, in Example 3, the precious metal enriched material obtained after processing the copper anode mud had a yield of 54%, an arsenic content reduced to 0.11%, and a removal rate of 98.92%.

[0122] Removal rates of base metals: copper 99.1%, nickel 92.4%, tin 91.5%, antimony 93.7%;

[0123] The enrichment factor for precious metals is 1.85.

[0124] Example 4

[0125] Example 4 uses copper anode mud from a smelter in Jiangxi Province. The representative sample contains the following valuable components: gold 6495.6 g / t, silver 14.60%, platinum 128.4 g / t, palladium 1005.6 g / t. The base metal content is: copper 20.21%, nickel 8.63%, tin 3.31%, antimony 8.35%, and arsenic 5.51%. The specific steps include:

[0126] (1) First, grind 1 kg of copper anode mud to a particle size of -200 mesh to -400 mesh. Mix the ingredients according to the mass ratio of copper anode mud: concentrated sulfuric acid: activated carbon powder: sodium chloride = 1:0.3:0.2:0.5 and mix them evenly. Place the resulting mixture in a muffle furnace or tube furnace equipped with a dust collection device for roasting. The first roasting condition is roasting at 330℃ for 4 hours.

[0127] (2) After the first roasting, the temperature is raised for a second roasting. The roasting conditions are 700℃ for 5 hours. After the reaction is completed, calcined sand is obtained.

[0128] (3) The calcined sand was transferred to a stirred leaching reactor for stirred leaching. The concentration of the dilute sulfuric acid solution was 50 g / L, the solid-liquid ratio of the calcined sand to the dilute sulfuric acid solution was 1:3, the leaching temperature was 50℃, and the leaching time was 2 h.

[0129] (4) After leaching, solid-liquid separation is carried out to obtain precious metal-enriched material and solution containing base metal.

[0130] Based on the analysis and calculations, in Example 4, the precious metal enriched material obtained after processing the copper anode mud had a yield of 49%, an arsenic content reduced to 0.08%, and a removal rate of 99.29%.

[0131] Base metal removal rates: copper 99.3%, nickel 93.6%, tin 91.7%, antimony 94.3%;

[0132] The enrichment factor for precious metals is 2.04.

[0133] In summary, the method for removing arsenic and enriching precious metals from anode mud provided in this application achieves efficient removal of arsenic, efficient separation of base metals, and efficient enrichment of precious metals from anode mud. The arsenic removal rate is >98%, the base metal removal rate is >90%, and there is almost no loss of precious metals in the anode mud. This method has advantages such as high arsenic removal rate, efficient enrichment and recovery of precious metals, and simple operation. It can effectively reduce reagent consumption and production costs in the process of recovering precious metals from anode mud, resulting in significant environmental and economic benefits and meeting the current requirements for clean production in green metallurgy and solid waste resource utilization.

[0134] Other configurations of the embodiments of this application, such as ... and ..., and operations, are known to those skilled in the art and will not be described in detail here.

[0135] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0136] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for removing arsenic and enriching precious metals from anode mud, characterized in that, The method includes: The ground anode mud is mixed with concentrated sulfuric acid, carbonaceous reducing agent, and chloride salt to form a mixture. The mixture is then subjected to a first roasting to convert the base metals in the anode mud into soluble salts and the arsenic-containing phase into arsenic trioxide. The temperature of the first roasting is 150℃-400℃. The mixture after the first roasting is heated and then roasted a second time to volatilize the arsenic trioxide, thereby obtaining roasted ore; wherein the temperature of the second roasting is 400℃-800℃; After acid leaching, the calcined sand is filtered to obtain a solution containing base metal salts and a precious metal concentrate. The base metals include at least copper, nickel, tin, and antimony; The precious metals include at least gold, silver, platinum, and palladium.

2. The method for removing arsenic and enriching precious metals from anode mud according to claim 1, characterized in that, The mass ratio of the anode mud to the concentrated sulfuric acid is 1:(0.1-1). The mass ratio of the anode mud to the carbonaceous reducing agent is 1:(0.05-1). The mass ratio of the anode mud to the chloride salt is 1:(0.1-1).

3. The method for removing arsenic and enriching precious metals from anode mud according to claim 1 or 2, characterized in that, The mass ratio of the anode mud to the concentrated sulfuric acid is 1:(0.2-0.4). The mass ratio of the anode mud to the carbonaceous reducing agent is 1:(0.1-0.2). The mass ratio of the anode mud to the chloride salt is 1:(0.2-0.5).

4. The method for removing arsenic and enriching precious metals from anode mud according to claim 1, characterized in that, The carbonaceous reducing agent is selected from at least one of activated carbon, bituminous coal, coke, and starch.

5. The method for removing arsenic and enriching precious metals from anode mud according to claim 1, characterized in that, The chloride salt is selected from at least one of sodium chloride, sodium hypochlorite, sodium chlorate, potassium chloride, potassium hypochlorite, and potassium chlorate.

6. The method for removing arsenic and enriching precious metals from anode mud according to claim 1, characterized in that, The first roasting time is 0.5h-4h.

7. The method for removing arsenic and enriching precious metals from anode mud according to claim 1, characterized in that, The second roasting time is 0.5h-6h.

8. The method for removing arsenic and enriching precious metals from anode mud according to claim 1, characterized in that, The particle size of the ground anode mud is -200 mesh to -400 mesh.

9. The method for removing arsenic and enriching precious metals from anode mud according to claim 1, characterized in that, The acid leaching process includes the following steps: The calcined sand is mixed with sulfuric acid solution and leached by stirring at 25℃-90℃; The stirring and leaching time is 0.5h-4h; The concentration of the sulfuric acid solution is 10 g / L to 50 g / L.

10. The method for removing arsenic and enriching precious metals from anode mud according to claim 9, characterized in that, The solid-liquid ratio of the calcined sand to the sulfuric acid solution is 1:(2-10)g / mL.

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