Method for leaching copper anode slime through circulating acid

Abstract

The invention discloses a method for leaching copper anode slime by circulating acid, which comprises the following steps: a slurrying process: putting the copper anode slime into a pre-slurrying reaction tank, adding circulating acid into the pre-slurrying reaction tank to carry out slurrying treatment to obtain slurrying liquid, the circulating acid being composed of sulfuric acid, sulfurous acid and selenic acid; the slurrying liquid is put into a primary leaching reaction tank, hydrochloric acid and sodium chloride are added into the primary leaching reaction tank for primary leaching, and primary leaching residues and primary leaching supernate are obtained; a secondary leaching procedure: adding circulating acid into the primary leaching residues again to obtain secondary leaching residues and secondary leaching supernate; the secondary leaching residues are pulpified through concentrated sulfuric acid, the secondary leaching residues and concentrated sulfuric acid are mixed to form pulpified matter, the pulpified matter is fed into a rotary kiln to be subjected to sulfating roasting, sulfating roasting is divided into four-section roasting, and crude selenium, steamed selenium residues and crude selenium supernate are obtained. And efficient separation of impurity elements such as copper, arsenic, antimony and bismuth from rare and precious metals in the copper anode slime can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of nonferrous metal smelting, and more particularly to a method for leaching copper anode mud using circulating acid. Background Art

[0002] my country is the world's largest producer of refined copper, with output reaching 12.988 million tons in 2023, accounting for approximately 44% of the global total. Copper anode slime, a byproduct of the copper electrolytic refining process, accounts for approximately 0.2% to 1.0% of total refined copper. As a key raw material for the comprehensive recovery of rare and precious metals in my country, copper anode slime is rich in precious metals such as gold, silver, platinum, palladium, and rhodium, as well as rare metals such as selenium and tellurium, and other non-ferrous metals such as copper and lead. Therefore, it is considered a significant "secondary resource." As my country's copper production grows, so too does the output of copper anode slime. The efficient resource utilization of valuable metals is not only of scientific interest but also holds significant economic value.

[0003] However, with the increasing diversification of copper smelting raw material sources and their decreasing grade, the grade of precious metals in copper anode mud has also gradually declined, resulting in a high content of impurity metals, a wide variety of impurity metals, and a complex phase structure. Valuable metals in copper anode mud typically exist in a variety of phases, including elemental elements, oxides, and complex compounds. To efficiently enrich and extract the precious metals from copper anode mud, leaching is often necessary. The primary purpose of leaching is to remove impurity elements such as copper, arsenic, antimony, and bismuth from the mud to facilitate subsequent extraction of the precious metals.

[0004] Currently, commonly used leaching processes include oxidation roasting, sulfuric acid roasting, sulfuric acid system pressure oxidation leaching, ultrasonic copper removal, and sulfuric acid-hydrochloric acid-sodium chloride compound acid leaching. While the sulfuric acid-hydrochloric acid-sodium chloride compound acid leaching process is widely used due to its high efficiency in impurity removal and improved recovery of impurity metals, it also faces challenges such as high acid consumption, high acid wastewater treatment costs, and high alkali consumption during acid neutralization. Therefore, improving the overall impurity removal efficiency of copper anode mud while reducing acid consumption and saving wastewater treatment costs is a pressing technical challenge in this field.

[0005] Chinese patent document (application number: 2015105109626, application date: 2015.08.20) discloses a method for comprehensive recovery of valuable metals from copper anode mud, comprising the following steps: (1) adding copper anode mud to a selenium-containing acidic solution, adding hydrochloric acid, controlling the liquid-solid ratio to 2-5:1, the reaction temperature to 60-90°C, the chloride ion concentration to 100-140 g / L, the reaction time to 2-5 hours, and performing a primary leaching to obtain a primary leachate and a primary leaching residue; adding the selenium-containing acidic solution to the primary leaching residue; The method comprises the following steps: introducing compressed air into the liquid for secondary leaching, controlling the liquid-to-solid ratio to 3-6:1, the reaction temperature to 60-90°C, and the reaction time to 2-5 hours, to obtain a secondary leachate and a secondary leachate residue; slurrying the secondary leachate residue with concentrated sulfuric acid for 0.5-1 hour, and then sulfating and roasting the residue at a temperature of 500-700°C for 2-3 hours; and subjecting the flue gas to three-stage absorption in an absorption tower, stirring the flue gas at room temperature for 8-12 hours, and filtering the flue gas to obtain crude selenium and a selenium-containing acidic solution, which is returned to the leaching process for reuse. The primary leachate and secondary leachate obtained in step (1) are uniformly mixed, and NaOH is added to adjust the pH of the mixed solution to 1.5-2. The reaction time is 0.5-2 hours, and a primary neutralization is performed to obtain a primary neutralized solution and a primary neutralized slag. NaOH is added to the primary neutralized solution to adjust the pH of the solution to 3-3.5. The reaction time is 0.5-2 hours, and a secondary neutralization is performed to obtain a secondary neutralized solution and a secondary neutralized slag. Lime is added to the secondary neutralized solution for precipitation, and the end point pH is controlled to 8-10. The solution is filtered to obtain copper-containing precipitated slag and a precipitated solution. Dilute sulfuric acid is added to the precipitated solution to adjust the pH to 5-7, and nano-zero-valent iron is added to control the potential for reaction. The solution is filtered. The filtrate is then subjected to oxidative aeration treatment and returned to the production system for reuse. In this scheme, the selenium-containing acidic solution includes selenium, sulfuric acid, and chloride ions. The total removal rate of copper in the subsequent copper anode mud needs to be further improved. Summary of the Invention

[0006] In view of this, the present invention provides a method for circulating acid leaching of copper anode mud, which can improve the comprehensive impurity removal efficiency of copper anode mud while reducing acid consumption and saving wastewater treatment costs.

[0007] The present application provides a method for cyclic acid leaching of copper anode mud, comprising the following steps:

[0008] Slurrying process: put the copper anode mud into the pre-slurrying reaction tank, add circulating acid into the pre-slurrying reaction tank for slurrying treatment, the acidity of the circulating acid is 200-400g / L, and the amount is 1.0-1.5m 3 / t copper anode slime, the slurrying time is 20min-120min, and the liquid-to-solid ratio is controlled at 2:1-8:1 to obtain a slurry liquid, wherein the circulating acid is composed of sulfuric acid, sulfurous acid and selenic acid, and the ratio of the sulfuric acid, the sulfurous acid and the selenic acid is 4:2:1-6:2:1;

[0009] Primary leaching process: putting the slurry into a primary leaching reaction tank, adding hydrochloric acid and sodium chloride into the primary leaching reaction tank for primary leaching, wherein the amount of the hydrochloric acid is 400-500 kg / t of copper anode mud, the amount of the sodium chloride is 50-100 kg / t of copper anode mud, the reaction temperature is 60° C.-95° C., the reaction time is 1 hour-8 hours, after the reaction is completed, cooling to 50° C.-60° C. and then performing solid-liquid separation, after solid-liquid separation, obtaining primary leaching residue and primary leaching supernatant, and retaining the primary leaching supernatant;

[0010] Secondary leaching process: add the circulating acid again to the primary leaching residue, the acidity of the circulating acid is 200-400 g / L, and the amount is 2-3 m 3 / t copper anode mud, the liquid-solid ratio is controlled at 2:1-8:1, the slurrying time is 30min-60min, the reaction temperature is 65-95°C, the reaction time is 3h-10h, after the reaction is completed, the temperature is lowered to 55°C-60°C, air is introduced, and the temperature is raised for secondary leaching, after solid-liquid separation, secondary leaching residue and secondary leaching supernatant are obtained, the secondary leaching supernatant and the primary leaching supernatant are purified to obtain purified slag, and copper, arsenic, antimony and bismuth therein are recovered;

[0011] Sulfate roasting process: the secondary leaching residue is slurried with concentrated sulfuric acid, the secondary leaching residue is mixed with the concentrated sulfuric acid to form a slurry, and the slurry is sent to a rotary kiln for sulfate roasting. The sulfate roasting is divided into four stages, and the temperatures of the four stages are 560-620°C, 580-620°C, 620-660°C, and 620-660°C, respectively. The time of each stage is the same, and the negative pressure of the rotary kiln is controlled at 3000-1500Pa to obtain crude selenium, steamed selenium residue and crude selenium supernatant, wherein the crude selenium supernatant is returned to the slurrying process and the secondary leaching process as the circulating acid.

[0012] Compared with the prior art, the method for leaching copper anode mud by circulating acid provided by the present invention achieves at least the following beneficial effects:

[0013] The method for circulating acid leaching of copper anode mud provided by the present invention performs segmented two-stage leaching on the copper anode mud, and the primary leaching process effectively removes most of the impurities such as copper, arsenic, antimony, bismuth, etc., reduces the processing volume of the secondary leaching process, and solves the production problem of difficult impurity removal; by performing secondary leaching on the primary leaching residue, the residual impurity elements can be effectively removed, and the amount of materials required to be processed in the subsequent sulfuric acid roasting process is significantly reduced, thereby improving resource utilization; the crude selenium supernatant produced by the sulfuric acid roasting in the rotary kiln is recycled and used in the slurry process and the secondary leaching process, thereby improving the resource recycling efficiency and reducing the production cost and the wastewater treatment volume. That is, the present invention realizes the efficient separation of impurity elements such as copper, arsenic, antimony, bismuth and rare metals in copper anode mud, solves the problems of large acid consumption and high wastewater treatment cost in the traditional acid leaching process, and the operation method is simple and easy, with good industrial production application prospects.

[0014] Of course, any product implementing the present invention does not necessarily need to achieve all of the technical effects described above at the same time.

[0015] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0017] Figure 1 The present invention provides a schematic flow diagram of a method for leaching copper anode mud using circulating acid. DETAILED DESCRIPTION

[0018] 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 of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0019] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0020] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0021] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0022] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0023] Reference Figure 1 As shown, Figure 1 Schematic diagram of the process of the method for cyclic acid leaching of copper anode mud provided by the present invention. This embodiment provides a method for cyclic acid leaching of copper anode mud, comprising the following steps:

[0024] Step 100: Slurrying process: put the copper anode mud into the pre-slurrying reaction tank, add circulating acid into the pre-slurrying reaction tank for slurrying treatment, the acidity of the circulating acid is 200-400g / L, and the amount is 1.0-1.5m 3 / t copper anode slime, the slurrying time is 20min-120min, the liquid-to-solid ratio is controlled at 2:1-8:1, and a slurry liquid is obtained, wherein the circulating acid is composed of sulfuric acid, sulfurous acid and selenic acid, and the ratio of sulfuric acid, sulfurous acid and selenic acid is 4:2:1-6:2:1;

[0025] Step 102: Primary leaching process: the slurry is put into a primary leaching reaction tank, and hydrochloric acid and sodium chloride are added to the primary leaching reaction tank to perform primary leaching. The amount of hydrochloric acid used is 400-500 kg / t copper anode mud, and the amount of sodium chloride used is 50-100 kg / t copper anode mud. The reaction temperature is 60° C. to 95° C., and the reaction time is 1 hour to 8 hours. After the reaction is completed, the temperature is lowered to 50° C. to 60° C. and solid-liquid separation is performed. After solid-liquid separation, primary leaching residue and primary leaching supernatant are obtained, and the primary leaching supernatant is retained.

[0026] Step 104: Secondary leaching process: add circulating acid to the primary leaching residue again. The acidity of the circulating acid is 200-400 g / L and the amount is 2-3 ml. 3 / t copper anode mud, the liquid-solid ratio is controlled at 2:1-8:1, the slurrying time is 30min-60min, the reaction temperature is 65-95°C, the reaction time is 3h-10h, after the reaction is completed, the temperature is lowered to 55°C-60°C, air is introduced, and the temperature is raised for secondary leaching, after solid-liquid separation, secondary leaching residue and secondary leaching supernatant are obtained, the secondary leaching supernatant and the primary leaching supernatant are purified to obtain purified slag, and copper, arsenic, antimony and bismuth therein are recovered;

[0027] Step 106 is a sulfation roasting process: the secondary leaching residue is slurried with concentrated sulfuric acid, the secondary leaching residue is mixed with concentrated sulfuric acid to form a slurry, and the slurry is sent to a rotary kiln for sulfation roasting. The sulfation roasting is divided into four stages. The temperatures of the four stages are 560°C to 620°C, 580°C to 620°C, 620°C to 660°C, and 620°C to 660°C, respectively. The time of each stage is the same, and the negative pressure of the rotary kiln is controlled at 3000 Pa to 1500 Pa to obtain crude selenium, steamed selenium residue and crude selenium supernatant. The crude selenium supernatant is returned to the slurrying process and the secondary leaching process as a circulating acid.

[0028] Specifically, the copper anode slime in the slurrying process in step 100 mainly comprises copper, gold, silver, arsenic, antimony, bismuth, selenium, tellurium, lead, nickel, tin, barium, iron, zinc, chromium, platinum, palladium, water, carbon, and oxygen. The copper anode slime is placed in a pre-slurrying reaction tank, and a circulating acid is added to the slurrying reaction tank. The circulating acid comprises sulfuric acid, sulfurous acid, and selenic acid. The ratio of sulfuric acid, sulfurous acid, and selenic acid can be 4:2:1 to 6:2:1, for example, the ratio of sulfuric acid, sulfurous acid, and selenic acid can be 4:2:1, 4.5:2:1, 5:2:1, 5.5:2:1, or 6:2:1.

[0029] The pre-slurry reaction tank is a device specially used for pre-treating copper anode mud. Its main function is to fully contact the copper anode mud with the circulating acid, so that the components in the copper anode mud can be better dissolved or reacted.

[0030] The circulating acid is derived from the acid produced by the chemical reaction in the sulfation and roasting process. This acid is composed of sulfuric acid, a small amount of sulfurous acid, and a trace amount of selenic acid. This acid is recycled and reused in the copper anode slime leaching process. Therefore, this acid is referred to as circulating acid in the present invention. Furthermore, the circulating acid is derived from the hydrochloric acid added in the primary leaching process, the concentrated sulfuric acid added in the sulfation and roasting process, and the selenic acid produced by the roasting process. In other words, the circulating acid is composed of sulfuric acid, sulfurous acid, and selenic acid.

[0031] If the mass fraction of sulfuric acid in the circulating acid is too high, the oxidizing property is too strong; if the mass fraction of sulfuric acid in the circulating acid is too low, the acidity is low. Therefore, the mass fraction of sulfuric acid in the circulating acid can be 57% to 66%, so that sulfuric acid plays an acidic and oxidizing role in the leaching process; the mass fraction of sulfuric acid in the circulating acid can be 57%, 59%, 61%, 63% or 66%.

[0032] The contents of sulfurous acid and selenic acid are positively correlated. If the mass fraction of sulfurous acid in the circulating acid is too high, it indicates that selenium is not completely volatilized and converted into elemental selenium during the sulfation roasting process, resulting in a low selenium conversion rate, which is not conducive to product recovery during production. If the mass fraction of sulfurous acid in the circulating acid is too low, hydrochloric acid needs to be supplemented during the pretreatment leaching process to supplement the acidity of the reaction system, increasing hydrochloric acid consumption. In this embodiment, the mass fraction of sulfurous acid in the circulating acid is 22% to 28%; the mass fraction of selenic acid in the circulating acid is 11% to 15%. This not only indicates that selenium is completely volatilized during the sulfation roasting process, improving the selenium conversion rate and facilitating product recovery during production, but also eliminates the need to supplement hydrochloric acid during the pretreatment leaching process to supplement the acidity of the reaction system, reducing hydrochloric acid consumption. The mass fraction of sulfurous acid in the circulating acid can be 22%, 23%, 24%, 25%, 26%, 27%, or 28%. The mass fraction of selenic acid in the circulating acid can be 11%, 12%, 13%, or 15%.

[0033] The advantages of this circulating acid are as follows:

[0034] 1. Composition: 1. Sulfuric acid in the circulating acid plays a primary role in the leaching process, acting as both acidic and oxidizing agents. 2. Sulfurous acid ionizes to produce hydrogen ions and sulfite. The hydrogen ions act as acid, aiding the leaching of copper anode mud, while the sulfite also binds to metal ions, aiding their dissolution. 3. Selenic acid also acts as an acid, aiding the leaching process. Furthermore, some selenic acid also chemically reacts to produce selenium (Se), which is recovered, increasing its recovery rate. Therefore, compared to single acid leaching, the circulating acid achieves a combined leaching effect, with sulfuric acid as the primary agent, supplemented by sulfurous acid and selenic acid.

[0035] Second, the circulating acid can be reused in the method of leaching copper anode mud with circulating acid, which has the effect of replacing new acid, thereby reducing the amount of new acid replenished, which can reduce the acid expansion of the system, reduce the consumption of new acid, reduce production costs, and is also beneficial to environmental protection.

[0036] If the acidity of the circulating acid in the slurrying process is too low, it means that the strength of the circulating acid is insufficient and the chemical reaction cannot be completed effectively. In order to achieve the desired reaction effect, more circulating acid needs to be added to supplement the acidity, which will lead to an increase in the amount of circulating acid added. Adding more acid will cause the liquid volume in the reaction system to increase. If the acidity of the circulating acid in the slurrying process is too high, the utilization efficiency of the circulating acid will be reduced, resulting in waste of circulating acid and an increase in processing costs. In this embodiment, the acidity of the circulating acid in the slurrying process is controlled at 200-400 g / L, which not only avoids adding too much circulating acid, thereby avoiding an increase in the liquid volume in the reaction system, but also improves the utilization rate of the circulating acid, avoids wasting circulating acid, and reduces processing costs. Specifically, in this embodiment, the acidity of the circulating acid in the slurrying process is controlled at 200 g / L, 250 g / L, 300 g / L, 350 g / L or 400 g / L.

[0037] If the amount of circulating acid used in the slurrying process is insufficient, and the solid-liquid ratio remains unchanged, additional liquid needs to be added to achieve the required solid-liquid ratio due to insufficient acid volume. These liquids can be hydrochloric acid (if acidity needs to be supplemented) or industrial water (if only volume needs to be supplemented). Adding additional industrial water or hydrochloric acid will increase the total volume of the liquid; if the amount of circulating acid used in the slurrying process is too much, it will lead to waste of acid and increase production costs. In this embodiment, the amount of circulating acid used in the slurrying process is controlled at 1.0m 3 / t~1.5m 3 / t copper anode mud, not only avoids adding hydrochloric acid or industrial water under the condition of unchanged solid-liquid ratio, thereby reducing the total volume of liquid as much as possible, but also avoids acid waste and reduces production costs. In this embodiment, the amount of circulating acid in the slurrying process can be controlled at 1.0m 3 / t、1.1m 3 / t、1.2m 3 / t、1.3m 3 / t、1.4m 3 / t or 1.5m 3 / tcopper anode mud.

[0038] During the slurrying process, a low liquid-to-solid ratio makes the slurry too thick, making it difficult to transport and resulting in poor leaching results. A high liquid-to-solid ratio during the slurrying process causes liquid expansion, increases the wastewater treatment volume, and affects the copper anode slime treatment capacity. In this embodiment, the liquid-to-solid ratio during the slurrying process is controlled within a range of 2:1 to 8:1. This not only prevents the slurry from being too thick, improving transportability and leaching results, but also prevents liquid expansion, reduces wastewater treatment volume, and avoids affecting the copper anode slime treatment capacity.

[0039] The liquid-to-solid ratio in the above slurrying process refers to the ratio between the volume of circulating acid and the mass of copper anode mud.

[0040] In the primary leaching process of step 102, the slurry is put into the primary leaching reaction tank for subsequent leaching reaction, such as adding hydrochloric acid and sodium chloride into the primary leaching reaction tank and heating the tank to carry out the primary leaching reaction.

[0041] If the amount of hydrochloric acid added in the primary leaching process is insufficient, the acidity of the primary leaching supernatant will be affected, reducing the impurity removal rate; if the amount of hydrochloric acid added in the primary leaching process is too high, the acidity will be too high, resulting in the loss of precious metals (such as silver) in the primary leaching residue.

[0042] In this example, the amount of hydrochloric acid used is controlled at 400-500 kg / t of copper anode slime. This not only minimizes the effect of acidity on the primary leaching supernatant, thus improving impurity removal efficiency, but also prevents excessive acidity, minimizing the loss of precious metals (such as silver) in the primary leaching residue. Hydrochloric acid is a strong acid that provides an acidic environment, dissolving metal oxides in the copper anode slime and forming soluble metal chlorides.

[0043] Insufficient sodium chloride usage results in low chloride concentrations in the primary leaching residue and primary leaching supernatant, affecting the removal of arsenic, antimony, and bismuth impurities. Excessive sodium chloride usage results in the loss of precious metals (silver). In this embodiment, the sodium chloride usage is controlled at 50-100 kg / t of copper anode mud. This not only avoids low chloride concentrations in the primary leaching residue and primary leaching supernatant, increasing the removal of arsenic, antimony, and bismuth impurities, but also prevents the loss of precious metals (silver). Sodium chloride provides chloride ions, which can form soluble chlorides with metal ions, thereby improving the leaching rate of the metal.

[0044] In the primary leaching process of step 102, if the reaction temperature is too low, the impurity removal effect is affected and the difficulty of filtering the slurry is increased. If the reaction temperature is too high, the slurry, hydrochloric acid and sodium chloride react violently. In this embodiment, the reaction temperature is controlled at 60°C to 95°C, which not only improves the impurity removal effect and reduces the difficulty of filtering the slurry, but also avoids violent reactions between the slurry, hydrochloric acid and sodium chloride. Higher temperatures can accelerate the rate of chemical reactions and dissolve metal oxides faster.

[0045] In step 102, during the primary leaching process, if the reaction time is insufficient, the reaction between the slurry, hydrochloric acid, and sodium chloride will not be sufficient, affecting the impurity removal effect. If the reaction time is too long, unnecessary energy consumption will increase. Therefore, in this embodiment, the reaction time is controlled within 1 hour to 8 hours. This not only allows for sufficient reaction between the slurry, hydrochloric acid, and sodium chloride, improving the impurity removal effect, but also reduces unnecessary energy consumption. The reaction time is long enough to ensure that most metals are fully dissolved.

[0046] In the primary leaching process of step 102, after the reaction is completed, if the temperature is lowered too low, the slurry will easily harden in the filter cloth, affecting the filtering effect. If the temperature is lowered too high, the service life of the filter cloth will be affected. In this embodiment, after the reaction is completed, the temperature is controlled to 50°C to 60°C before solid-liquid separation. This not only prevents the slurry from hardening in the filter cloth, improves the filtering effect, but also increases the service life of the filter cloth. The purpose of cooling is to reduce the saturation of the solution, reduce the solubility of impurities, and facilitate subsequent solid-liquid separation operations. The primary leaching residue (solid) is separated from the primary leaching supernatant (liquid) by filtration. The primary leaching residue mainly contains undissolved solid residue and may contain some unleached metals or other impurities. The primary leaching supernatant contains dissolved metals such as antimony Sb, bismuth Bi, and copper Cu, which are raw materials for subsequent extraction of valuable metals.

[0047] The primary leaching reaction of the slurry in step 102 is as follows:

[0048] H2SeO3+4HCl+2Cu=2CuCl2+Se+3H2O. In this reaction formula, selenic acid H2SeO3 is a selenium-containing inorganic acid with acidity; hydrochloric acid HCl is a strong acid with corrosiveness; copper Cu is a metal with reducing properties, and copper chloride CuCl2 is a blue salt that is soluble in water; selenium Se is a non-metallic element, and water H2O is a colorless and odorless liquid. This reaction formula is a redox reaction. The acidic environment and the reducing properties of the metal achieve the reduction of selenium and the oxidation of copper.

[0049] Bi2O3+6HCl=2BiCl3+3H2O. In this reaction formula, bismuth oxide Bi2O3 is a bismuth oxide, hydrochloric acid HCl is a strong acid, bismuth chloride BiCl3 is a bismuth chloride, and water H2O is a colorless and odorless liquid. Bismuth oxide Bi2O3 reacts with hydrochloric acid HCl to generate bismuth chloride BiCl3 and water H2O. This reaction formula is an acid-base reaction. Bismuth oxide Bi2O3, as an alkaline oxide, reacts with acidic hydrochloric acid HCl to generate bismuth chloride BiCl3 (salt) and water H2O.

[0050] Sb2O3+6HCl=2SbCl3+3H2O. In the reaction formula, antimony oxide Sb2O3 is an antimony oxide, hydrochloric acid HCl is a strong acid, antimony chloride SbCl3 is an antimony chloride, and water H2O is a colorless and odorless liquid. Antimony oxide Sb2O3 reacts with hydrochloric acid HCl to generate antimony chloride SbCl3 and water. This reaction formula is an acid-base reaction. Antimony oxide Sb2O3, as an alkaline oxide, reacts with acidic hydrochloric acid HCl to generate antimony chloride SbCl3 (salt) and water.

[0051] Sb 3+ +Cl - +H2O=SbOCl+2H + In this reaction, antimony ion Sb 3+It is a positive trivalent ion of antimony, chloride ion Cl - It is a monovalent ion of chlorine. Water H2O is a colorless and odorless liquid. Antimony chloride SbOCl is an oxygen-containing salt of antimony. The hydrogen ion H + It is a monovalent hydrogen ion, antimony ion Sb 3+ With chloride ion Cl - Reacts with water H2O to generate antimonate chloride SbOCl and 2 hydrogen ions H + , the reaction is a hydrolysis reaction, antimony ion Sb 3+ Hydrolyzes in water to form antimonate chloride SbOCl and hydrogen ions H + .

[0052] CuO+2H + =Cu 2 +H2O, the reaction formula is copper oxide CuO is a copper oxide, hydrogen ion H + It is a monovalent hydrogen ion, copper ion Cu 2 It is a divalent copper ion. Water H2O is a colorless and odorless liquid. Copper oxide CuO and hydrogen ions H + Reaction to generate copper ions Cu 2 and water H2O. This reaction is an acid-base reaction. Copper oxide CuO acts as an alkaline oxide and reacts with acidic H + The reaction generates copper ions Cu 2 (salt) and water H2O.

[0053] In step 104, circulating acid is added to the primary leaching residue to further leach the valuable metals in the primary leaching residue. The introduction of air provides oxygen to promote the oxidation reaction, while increasing the temperature accelerates the reaction rate and improves the leaching efficiency. After solid-liquid separation, secondary leaching residue and secondary leaching supernatant are obtained. The secondary leaching residue (solid residue) and the secondary leaching supernatant (liquid leachate) are separated by solid-liquid separation.

[0054] The secondary leaching reaction of the primary leaching residue in step 104 is as follows:

[0055] H2SeO3+4H + +2Cu=2Cu 2+ +Se+3H2O, the reactants in this reaction are selenic acid H2SeO3, hydrogen ion H + and copper Cu, the product is copper ion Cu 2+ , selenium Se and water H2O, extract copper ions from selenic acid and copper, and generate selenium at the same time.

[0056] CuO+H2SO4=CuSO4+H2O. In this reaction formula, the reactants are copper oxide CuO and sulfuric acid H2SO4, and the products are copper sulfate CuSO4 and water H2O. Copper ions are extracted from copper oxide to produce soluble copper sulfate.

[0057] Cu+H2SO4+1 / 2O2=CuSO4+H2O. In this reaction formula, the reactants are copper Cu, sulfuric acid H2SO4 and oxygen O2, and the products are copper sulfate CuSO4 and water H2O. Copper ions are directly extracted from copper to produce soluble copper sulfate.

[0058] Cu2Te+2H2SO4+2O2=2CuSO4+H2TeO3+2H2O. In this reaction formula, the reactants are dicopper tellurium Cu2Te, sulfuric acid H2SO4 and oxygen O2, and the products are copper sulfate CuSO4, telluric acid H2TeO3 and water H2O. Copper ions are extracted from dicopper tellurium and telluric acid is generated at the same time.

[0059] Cu2Se+2H2SO4+2O2=2CuSO4+H2SeO3+2H2O. In this reaction formula, the reactants are dicopper tellurium Cu2Se, sulfuric acid H2SO4 and oxygen O2, and the products are copper sulfate CuSO4, telluric acid H2SeO3 and water H2O. Copper ions are extracted from dicopper tellurium and telluric acid is generated at the same time.

[0060] Cu+2H2SO4+H2SeO3=2CuSO4+3H2O+Se. In this reaction formula, the reactants are copper, sulfuric acid H2SO4 and selenic acid H2SeO3, and the products are copper sulfate CuSO4, water H2O and selenium Se. Copper ions are extracted from copper and selenic acid, and selenium is produced at the same time.

[0061] 2H2SO3+O2=2H2SeO4. In this reaction formula, the reactants are sulfurous acid H2SO3 and oxygen O2, and the product is selenic acid. Sulfous acid is oxidized to selenic acid for subsequent reactions.

[0062] 2H2SeO4+CuO=CuSeO4+H2O. In this reaction formula, the reactants are selenic acid H2SeO4 and copper oxide CuO, and the products are copper selenate CuSeO4 and water. Copper ions are extracted from copper oxide to produce copper selenate.

[0063] 2H2SeO4+Cu+O2=2CuSeO4+2H2O. In this reaction formula, the reactants are selenic acid H2SeO4, copper Cu and oxygen O2, and the products are copper selenate CuSeO4 and water H2O. Copper ions are extracted from copper to produce copper selenate.

[0064] 2H2SeO4+2CuS+3O2=2CuSeO4+2H2O+SO2, in which the reactants are selenic acid H2SeO4, copper sulfide CuS and oxygen O2, and the products are copper selenate CuSeO4, water H2O and sulfur dioxide SO2.

[0065] Through the secondary leaching reaction of the primary leaching residue, copper and its associated elements (such as selenium and tellurium) are extracted from the primary leaching residue, and soluble copper salts (such as copper sulfate and copper selenate) are generated. These copper salts can be further used for copper extraction and purification, and the associated elements can also be recycled.

[0066] The primary leaching supernatant and the secondary leaching supernatant are retained and subsequently separated into copper (Cu), antimony (Sb), bismuth (Bi), etc.; if the secondary leaching supernatant and the primary leaching supernatant are purified and the copper, arsenic, antimony and bismuth therein are recovered, the impurities are precipitated to form purified slag, thereby removing impurities and recovering valuable metals, and the valuable metals are recovered through subsequent processes.

[0067] Since the acidity of the circulating acid in the secondary leaching process is the same as that in the slurrying process, that is, the circulating acid with the same acidity is used, the process flow is simplified and the steps of preparing the circulating acid are reduced, or because the acidity requirements of the secondary leaching process and the slurrying process are consistent.

[0068] The amount of copper anode mud used in the slurrying process is less than that in the secondary leaching process. In addition to adding circulating acid, the slurrying process also needs to add hydrochloric acid and sodium chloride. Its main purpose is to remove impurities such as arsenic, antimony and bismuth in the copper anode mud. The secondary leaching process mainly processes step 102 of the primary leaching process, the purpose of which is to remove impurity copper. The required acidity is relatively low, and no other chemical reagents need to be added.

[0069] In step 104, the acidity of the circulating acid in the secondary leaching process is controlled at 200 g / L to 400 g / L, ensuring a sufficiently acidic environment so that the metals (such as copper, arsenic, antimony and bismuth) in the primary leaching residue can be fully dissolved to form soluble sulfates, thereby inhibiting the dissolution of some impurities, reducing the entry of impurities into the secondary leaching solution, and improving the purity of the target metal.

[0070] Step 104: The amount of circulating acid in the secondary leaching process is controlled at 2m 3 / t~3m 3 Each ton of copper anode slime requires 2 to 3 cubic meters of circulating acid. This sufficient amount of acid ensures that the metal in the primary leaching residue is fully in contact with the circulating acid to complete the reaction. By controlling the amount used, excessive acid use can be avoided, reducing costs and the burden of subsequent treatment.

[0071] In step 104, the liquid-to-solid ratio in the secondary leaching process is controlled at 2:1 to 8:1, which not only ensures that the circulating acid is fully in contact with the primary leaching residue and improves the reaction efficiency, but also dilutes the concentration of the circulating acid, reduces the reaction rate, and avoids excessive reaction. At the same time, it prevents the liquid volume from being too large and exceeding the equipment capacity.

[0072] In step 104, the slurrying time in the secondary leaching process is controlled between 30 and 60 minutes to ensure that the copper anode mud is thoroughly mixed with the circulating acid, uniformly disperse the solid particles in the liquid, and improve reaction efficiency. The slurrying time refers to the time it takes to mix and stir the primary leaching residue with the circulating acid, and is generally used to ensure that the primary leaching residue is fully dispersed in the liquid.

[0073] In step 104, the reaction temperature in the secondary leaching process is controlled between 65°C and 95°C. This not only accelerates the chemical reaction and improves leaching efficiency, but also prevents side reactions and increases the recovery rate of the target metal. The reaction temperature refers to the temperature of the reaction system during the slurrying process and is generally controlled between 65°C and 95°C.

[0074] The reaction time in step 104 during the secondary leaching process is 3-10 hours. Sufficient reaction time ensures sufficient dissolution of the metal in the copper anode mud and achieves the desired leaching rate. Excessive reaction time may cause equipment wear and increase energy consumption. The reaction time refers to the total time from the start of slurrying to the end of the reaction, and typically takes 3-10 hours.

[0075] After the reaction is completed, the temperature of the reaction system needs to be lowered to 55°C-60°C. By controlling the acidity, dosage, liquid-to-solid ratio, temperature and time, the metal in the primary leaching residue is fully dissolved, the leaching efficiency is improved, the reaction conditions are optimized, the recovery rate of the target metal is increased, and resource waste is reduced.

[0076] In step 106, the secondary leaching residue undergoes a sulfation reaction with concentrated sulfuric acid at high temperature. The reaction is as follows:

[0077] (1) Lead in copper anode mud mainly exists in the form of lead sulfate PbSO4, so most of the Pb does not participate in the reaction during roasting. Only a very small amount of lead sulfide PbS reacts with concentrated sulfuric acid H2SO4 to generate lead sulfate PbSO4 and hydrogen sulfide H2S. The reaction formula is as follows:

[0078] PbS+H2SO4→PbSO4+H2S, through the sulfation reaction, lead sulfide PbS is converted into lead sulfate PbSO4, so that the lead is fixed in the secondary leaching residue in the form of sulfate, which is convenient for subsequent separation and treatment. The generated hydrogen sulfide H2S can be recovered or purified through subsequent treatment processes to reduce environmental pollution.

[0079] (2) Copper in copper anode mud mainly exists in the form of cuprous selenide Cu2Se, cuprous telluride Cu2Te and metallic copper. During the roasting process, copper will undergo the following reactions:

[0080] In the low temperature range (such as 560℃~620℃): copper metal Cu and concentrated sulfuric acid generate copper sulfate CuSO4, water H2O and sulfur dioxide SO2 under the action of heating: copper metal Cu is converted into soluble copper sulfate CuSO4, which is convenient for subsequent leaching and recovery. The reaction formula is as follows:

[0081] Cu+2H2SO4→CuSO4+2H2O+SO2,

[0082] Copper selenide (Cu2Se) reacts with concentrated sulfuric acid (H2SO4) under heating: At low temperatures, the copper selenide (Cu2Se) reacts with the concentrated sulfuric acid (H2SO4) to produce copper sulfate (CuSO4), copper selenate (CuSeO3), and sulfur dioxide (SO2). Copper selenate (CuSeO3) is unstable at high temperatures and decomposes into selenium dioxide (SeO2) and copper oxide (CuO). This reaction converts the copper in the copper selenide into copper sulfate (CuSO4) or copper oxide (CuO), facilitating subsequent copper recovery. The selenium dioxide (SeO2) produced can be used for selenium recovery.

[0083] Cu2Se+5H2SO4→CuSO4+CuSeO3+4SO2+5H2O,

[0084] The generated copper selenate CuSeO3 is unstable and decomposes at high temperature (such as 620℃~660℃). The reaction formula is as follows:

[0085] CuSeO3→SeO2+CuO,

[0086] Copper telluride (Cu2Te) and concentrated sulfuric acid (H2SO4) do not react at low temperatures, but react at high temperatures to produce copper tellurate (CuTeO3). Copper telluride (Cu2Te) reacts with concentrated sulfuric acid at high temperatures to produce copper sulfate (CuSO4) and copper tellurate (CuTeO3). Because copper tellurate (CuTeO3) is unstable, it decomposes into tellurium dioxide (TeO2) and copper oxide (CuO). The reaction formula is as follows:

[0087] Cu2Te+5H2SO4→CuSO4+CuTeO3+4SO2+5H2O,

[0088] CuTeO3 is unstable and can be decomposed into TeO2 when heated.

[0089] CuTeO3→TeO2+CuO,

[0090] Since cuprous sulfide (Cu2S) reacts strongly with concentrated sulfuric acid (H2SO4), a redox reaction occurs in the low-temperature region: Cu2S undergoes a redox reaction with concentrated sulfuric acid in the low-temperature region to produce copper sulfate (CuSO4), water (H2O), and sulfur dioxide (SO2). The copper in the copper sulfide is converted into soluble CuSO4, which facilitates subsequent leaching and recovery.

[0091] Cu2S+6H2SO4→2CuSO4+6H2O+5SO2.

[0092] Through sulfuric acid roasting, valuable metals (such as copper and lead) in copper anode mud are converted into soluble sulfates or oxides, facilitating subsequent leaching and recovery, thereby improving resource utilization. By controlling reaction conditions, the emission of harmful gases (such as hydrogen sulfide (H2S) and sulfur dioxide (SO2)) is reduced, and these gases are recovered or purified, reducing environmental pollution. Harmful components in copper anode mud (such as lead sulfide (PbS) and cuprous selenide (Cu2Se)) are converted into stable compounds and fixed in the secondary leaching residue, facilitating subsequent harmless treatment and reducing potential environmental damage.

[0093] In the sulfate roasting process in step 106, the sulfate roasting is divided into four stages. If the temperature of each stage is too low, the reaction rate is reduced, and the selenium dioxide SeO2 cannot be fully volatilized, which affects the recovery of Se and causes the metallic Se in the sulfate roasting slag to increase, affecting the next process. If the temperature of each stage is too high, the low melting point substances (arsenic, antimony, lead) will volatilize in large amounts and volatilize together with the selenium dioxide SeO2. After being absorbed by the water in the absorption tower, the crude selenium grade will be affected. At the same time, the temperature is too high, C uSO4 decomposes into CuO, causing agglomeration, affecting the normal operation of the rotary kiln and making the copper separation process difficult; in this embodiment, the temperatures of the four-stage roasting are controlled at 560-620°C, 580-620°C, 620-660°C, and 620-660°C, respectively, which can not only increase the reaction speed, ensure the full volatilization of selenium dioxide SeO2, and increase the metallic Se in the sulfated roasting slag, but also improve the grade of crude selenium, while avoiding the compaction of the secondary leaching slag, and further reduce energy consumption.

[0094] Since this embodiment adopts four-stage roasting, compared with three-stage roasting, the roasting effect is more sufficient, the selenium vaporization recovery effect is good, and the copper and silver in the copper anode mud are better converted into corresponding sulfates.

[0095] The above four-stage roasting includes the first stage, the second stage, the third stage and the fourth stage.

[0096] The first section mentioned above is the low-temperature drying area, which is mainly responsible for the following:

[0097] (1) Dehydration and preheating of secondary leaching residue: mainly removes free water and part of crystallization water in copper anode mud to avoid material splashing or agglomeration due to sudden evaporation of water in subsequent high-temperature areas;

[0098] (2) Initial sulfation reaction initiation: The sulfation reaction of non-precious metals (such as copper) is initiated at low temperature; at the same time, selenides (such as Ag2Se) begin to decompose to form selenite (SeSO3), preparing for selenium volatilization;

[0099] The second section is the medium temperature reaction zone, which is mainly responsible for the following:

[0100] (1) Deep decomposition of selenide: The increase in temperature causes the selenide to completely decompose into gaseous SeSO2. During this stage, the volatility of selenium increases significantly, ensuring that selenium enters the gas phase in the form of SeSO2.

[0101] (2) Inhibition of tellurium volatilization: Telluride (such as Ag2Te) generates non-volatile TeO2 and SO3 at this temperature, which are fixed in the secondary leaching residue to achieve selective separation of selenium / tellurium.

[0102] The third section is the high-temperature volatilization zone, which is mainly responsible for the following:

[0103] (1) Efficient selenium removal: Accelerate the sublimation of SeO2 above 600℃ to ensure that the residual selenium is completely volatilized, and the selenium removal rate can reach more than 95%;

[0104] (2) Avoid sulfate decomposition: strictly control the temperature below 650℃ (the decomposition temperature of copper sulfate) to prevent copper and other sulfates from decomposing into oxides and affecting the subsequent leaching efficiency. Of course, according to actual conditions, the temperature of the high-temperature volatilization zone can be appropriately adjusted as long as it is designed to be between 620℃ and 660℃.

[0105] The fourth section is the discharge stabilization area, which is mainly responsible for the following:

[0106] Selenium slag homogenization and discharge preparation: The roasted sand completes the final reaction in this area, forming a stable porous structure, which is conducive to the dissolution of copper and silver sulfates during subsequent acid leaching.

[0107] Crude selenium in step 106: The mass of selenium extracted from each ton of dry copper anode mud ranges from 50kg to 70kg. This selenium is initially extracted and contains impurities, hence the name "crude selenium." Because of the impurities, crude selenium cannot be directly used as a high-purity selenium product. Therefore, further impurity removal and refining are required to extract high-purity selenium (typically with a purity of 99.99% or higher).

[0108] Selenium slag steaming in step 106: During the process of extracting crude selenium, the remaining residue mass ranges from 500kg to 600kg, and the residue still contains other valuable metals. Selenium slag steaming contains rare precious metals and scattered metals, wherein rare precious metals include gold Au, silver Ag, platinum Pt and palladium Pd, and scattered metals include tellurium Te and the like. The above-mentioned rare precious metals and scattered metals have high economic value, so further processing is required to recover the above-mentioned rare precious metals and scattered metals. Through the wet leaching process, the different rare precious metals and scattered metals in the selenium slag steaming can be gradually separated. Cascade separation is an efficient metal recovery method, which extracts metals such as gold Au, silver Ag, platinum Pt, palladium Pd and tellurium Te in turn through a series of chemical reactions and separation steps.

[0109] Optionally, the purity of the concentrated sulfuric acid in the above-mentioned sulfation roasting step is ≥98%, and the ratio of the amount of concentrated sulfuric acid used to the weight of the secondary leaching residue is 0.6 to 1.8, that is, the concentrated sulfuric acid can be high-purity concentrated sulfuric acid. High-purity concentrated sulfuric acid not only has stronger oxidizing and acidic properties, but can also more effectively react with metal sulfides (such as cuprous sulfide Cu2S, copper selenide Cu2Se and copper telluride Cu2Te, etc.) or oxides in the ore to form soluble sulfates; it can also reduce the content of impurities in the sulfuric acid, avoid side reactions between impurities and other components in the ore, thereby improving the recovery rate of the target metal, while improving the utilization efficiency of sulfuric acid and reducing sulfuric acid waste.

[0110] The ratio of the amount of concentrated sulfuric acid to the weight of the secondary leaching residue is referred to as the mud acid ratio. If the mud acid ratio is too low, some components in the secondary leaching residue cannot fully react with the concentrated sulfuric acid, resulting in incomplete reaction. If the mud acid ratio is too high, the excess concentrated sulfuric acid will not only increase the cost, but also lead to aggravated corrosion of the rotary kiln, even cause safety accidents, and increase the difficulty of subsequent treatment. In this embodiment, the ratio of the amount of concentrated sulfuric acid to the weight of the secondary leaching residue can be a mud acid ratio of 0.6 to 1.8, that is, the mud acid ratio can be 0.6 to 1.8, which not only allows some components in the secondary leaching residue to fully react with sulfuric acid, but also reduces costs, avoids aggravated corrosion of the rotary kiln, avoids safety accidents, and reduces the difficulty of subsequent treatment. In this embodiment, the mud acid ratio can be 0.6, 0.7, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7 or 1.8.

[0111] Compared with the prior art, the method for leaching copper anode slime by circulating acid provided in this embodiment achieves at least the following beneficial effects:

[0112] The method for cyclic acid leaching of copper anode slime provided in this embodiment performs two staged leaching of the copper anode slime (a primary leaching process and a secondary leaching process). The primary leaching process effectively removes most impurities such as copper, arsenic, antimony, and bismuth, reduces the processing capacity of the secondary leaching process, and solves the production problem of difficult impurity removal. The secondary leaching of the primary leaching residue can effectively remove residual impurity elements, significantly reduce the amount of material required to be processed in the subsequent sulfuric acid roasting process, and improve resource utilization. The crude selenium supernatant produced by sulfuric acid roasting in a rotary kiln is recycled and used in the slurrying process and the secondary leaching process, thereby improving resource recycling efficiency and reducing production costs and wastewater treatment volume. In other words, the present invention achieves efficient separation of impurity elements such as copper, arsenic, antimony, and bismuth from rare and precious metals in copper anode slime, solves the problems of large acid consumption and high wastewater treatment costs in traditional acid leaching processes, and has a simple and easy operation method, which has good prospects for industrial production and application.

[0113] Optionally, the roasting time of each stage is 30 minutes to 37.5 minutes.

[0114] Specifically, in the sulfation roasting process using a rotary kiln, the four roasting stages all have the same duration. This is because the rotary kiln roasting process is a continuous operation. The secondary leaching residue is slurried with concentrated sulfuric acid and then fed into the rotary kiln together. The rotary kiln includes a kiln barrel and a spiral. The kiln barrel can be 12 meters long and has a kiln head and a kiln tail. The material enters from the kiln head and is discharged from the kiln tail. The four roasting stages are completed within the kiln barrel. The slurry is driven by the spiral from the kiln head to the kiln tail. The entire process takes 120 minutes to 150 minutes, and each roasting stage lasts 30 minutes to 37.5 minutes. This provides sufficient time for the chemical reaction to fully react with the target components in the slurry. This not only reduces unreacted residues in the material, improves resource utilization, and reduces the burden of subsequent processing, but also allows the material to gradually complete the reaction under different temperature and atmosphere conditions. This step-by-step reaction method ensures reaction uniformity.

[0115] In an optional embodiment, the secondary leaching process, wherein the secondary leaching supernatant and the primary leaching supernatant are purified to obtain purified slag, comprises:

[0116] After the secondary leaching supernatant is mixed with the primary leaching supernatant, liquid alkali is added to adjust the pH value to 3.5 to obtain purified slag.

[0117] Specifically, the secondary leaching supernatant is mixed with the primary leaching supernatant for centralized treatment, which can reduce the number of operating steps and simplify the process flow. In this embodiment, the liquid caustic soda can be sodium hydroxide (NaOH). A pH of 3.5 is a relatively low acidic environment. By adjusting the pH value, some copper, arsenic, antimony, and bismuth can be precipitated as hydroxides. Purified slag can be obtained by filtration, thereby achieving purification.

[0118] The above-mentioned purification slag refers to the solid matter precipitated during the purification process, which is usually composed of insoluble metal hydroxides, oxides or other impurities.

[0119] Example 1:

[0120] Take 500g of copper anode mud, the main components and their mass percentages are: copper Cu23.03%, Au0.28%, Ag5.90%, As5.86%, Sb3.81%, Bi1.60%, Se3.75%, Te1.92%, Pb3.02%, Ni0.73%, Sn2.41%, Ba9.55%, Fe0.11%, Zn0.12%, Cr0.009%, Pt0.0012%, Pd0.0046, H2O30.14% and the rest are other C and O elements.

[0121] Step 100: Slurrying process: Circulating acid is added to the copper anode slime for slurrying. The acidity of the circulating acid is controlled at 200g / L, and the amount of circulating acid required for each ton of copper anode slime is 1000ml. The circulating acid is composed of sulfuric acid, sulfurous acid, and selenic acid. The slurrying time is set to 20 minutes, and the liquid-to-solid ratio is 2:1. Step 102: Primary leaching process: During the slurrying process, 400kg of hydrochloric acid and 50kg of sodium chloride are added per ton of copper anode slime. The reaction temperature is raised to 60°C and the reaction is continued for 1 hour. After the reaction is completed, the temperature is rapidly cooled to below 60°C, and the slurry is discharged for solid-liquid separation to obtain a primary leaching residue and a primary leaching supernatant. During this process, the copper removal rate of the copper anode slime reached 63.58%, the arsenic removal rate was 95.28%, the antimony removal rate was 96.58%, and the bismuth removal rate was 97.47%. In step 104, the secondary leaching process involves adding circulating acid to the primary leaching residue again, with the acidity of the circulating acid still controlled at 200 g / L. When treating the primary leaching residue, 2000 ml of circulating acid is required per ton of copper anode mud. The slurrying time is extended to 30 minutes, and the liquid-solid ratio is adjusted to 2:1. The reaction is carried out at a reaction temperature of 65°C, with air introduced, for 3 hours. After the reaction is completed, the temperature is lowered to below 60°C, and solid-liquid separation is performed to obtain secondary leaching residue and secondary leaching supernatant, achieving deep copper removal, with a copper removal rate of 76.81%. Step 106 is a sulfation roasting process, in which the secondary leaching residue is slurried using concentrated sulfuric acid with a concentration of 98%, and then transferred to a rotary kiln for roasting. The sulfation roasting is divided into four stages, with the temperature of the first stage controlled at 560°C, the temperature of the second stage controlled at 560°C, the temperature of the third stage controlled at 620°C, and the temperature of the fourth stage controlled at 620°C. The negative pressure of the rotary kiln is -1500 Pa, and finally crude selenium, steamed selenium residue and crude selenium supernatant are obtained.

[0122] In summary, after the secondary leaching treatment, the total removal rate of copper in the copper anode mud reached 92.00%, the removal rate of arsenic was 96.38%, the removal rate of antimony was 97.49%, and the removal rate of bismuth was 98.32%.

[0123] Example 2

[0124] Take 500g of copper anode mud, the main components and their mass percentages are: Cu22.18%, Au0.21%, Ag5.38%, As5.66%, Sb3.14%, Bi1.80%, Se3.71%, Te1.10%, Pb5.98%, Ni0.87%, Sn2.26%, Ba10.71%, Fe0.32%, Zn0.13%, Cr0.01%, Pt0.0014%, Pd0.0056%, H2O30.82% and the rest are other C and O elements.

[0125] Step 100: Slurrying process: Circulating acid is added to the copper anode slime for slurrying. The acidity of the circulating acid is controlled at 400 g / L, and the required amount of circulating acid per ton of copper anode slime is 1500 ml. The circulating acid is composed of sulfuric acid, sulfurous acid, and selenic acid. The slurrying time is set to 120 minutes, and the liquid-to-solid ratio is 8:1. Step 102: Primary leaching process: During the slurrying process, 500 kg of hydrochloric acid and 100 kg of sodium chloride are added per ton of copper anode slime. The reaction temperature is raised to 95°C and the reaction is continued for 8 hours. After the reaction is completed, the temperature is rapidly cooled to below 60°C, and the slurry is discharged for solid-liquid separation to obtain a primary leaching residue and a primary leaching supernatant. During this process, the copper removal rate of the copper anode slime reaches 65.84%, the arsenic removal rate is 96.36%, the antimony removal rate is 98.09%, and the bismuth removal rate is 97.81%. In step 104, the secondary leaching process, circulating acid is added to the primary leaching residue again. The acidity of the circulating acid is still controlled at 400g / L. When treating the primary leaching residue, 3000ml of circulating acid needs to be added per ton of copper anode mud. The slurrying time is extended to 60min, and the liquid-solid ratio is adjusted to 8:1. At a reaction temperature of 95°C, air is introduced to react for 10 hours. After the reaction is completed, the temperature is lowered to below 60°C, and solid-liquid separation is performed to obtain secondary leaching residue and secondary leaching supernatant. Step 102 The primary leaching process achieves deep removal of copper, with a copper removal rate of 80.13%. In step 106, the secondary leaching residue is slurried using concentrated sulfuric acid with a concentration of 98%, and then transferred to a rotary kiln for roasting. The sulphation roasting is divided into four stages, with the temperature of the first stage controlled at 620°C, the temperature of the second stage controlled at 620°C, the temperature of the third stage controlled at 660°C, and the temperature of the fourth stage controlled at 660°C. The negative pressure of the rotary kiln is -3000Pa, and crude selenium, steamed selenium residue and crude selenium supernatant are finally obtained.

[0126] In summary, after the secondary leaching treatment, the total removal rate of copper in the copper anode mud reached 93.21%, the removal rate of arsenic was 97.31%, the removal rate of antimony was 98.93%, and the removal rate of bismuth was 98.32%.

[0127] Example 3

[0128] Take 500g of copper anode mud, the main components and their mass percentages are: Cu22.56%, Au0.23%, Ag4.53%, As5.34%, Sb3.62%, Bi1.67%, Se3.83%, Te1.79%, Pb 4.53%, Ni0.99%, Sn0.96%, Ba11.89%, Fe0.078%, Zn0.072%, Cr0.034%, Pt0.0013%, Pd0.0052, H2O29.51% and the rest are other C and O elements.

[0129] Step 100: Slurrying process: Circulating acid is added to the copper anode slime for slurrying. The acidity of the circulating acid is controlled at 300 g / L. 750 ml of circulating acid is required per ton of copper anode slime. The circulating acid is composed of sulfuric acid, sulfurous acid, and selenic acid. The slurrying time is set to 80 minutes, and the liquid-to-solid ratio is 5:1. Step 102: Primary leaching process: During the slurrying process, 450 kg of hydrochloric acid and 75 kg of sodium chloride are added per ton of copper anode slime. The reaction temperature is raised to 75°C and the reaction is continued for 6 hours. After the reaction is completed, the temperature is rapidly cooled to below 60°C, and the slurry is discharged for solid-liquid separation to obtain a primary leaching residue and a primary leaching supernatant. During this process, the copper removal rate of the copper anode slime reaches 67.26%, the arsenic removal rate is 96.12%, the antimony removal rate is 98.38%, and the bismuth removal rate is 96.95%. Step 104: Secondary leaching process: Circulating acid is added to the primary leaching residue again, with the acidity of the circulating acid still controlled at 300g / L. When treating the primary leaching residue, 2500ml of circulating acid is required per ton of copper anode mud. The slurrying time is extended to 60 minutes, and the liquid-solid ratio is adjusted to 5:1. The reaction is carried out at a reaction temperature of 85°C, with air introduced, for 7 hours. After the reaction is completed, the temperature is lowered to below 60°C, and solid-liquid separation is performed to obtain secondary leaching residue and secondary leaching supernatant, achieving deep copper removal, with a copper removal rate of 82.24%. In step 106, the secondary leaching residue is slurried using concentrated sulfuric acid with a concentration of 98%, and then transferred to a rotary kiln for roasting. The sulphation roasting is divided into four stages, with the temperature of the first stage controlled at 600°C, the temperature of the second stage controlled at 600°C, the temperature of the third stage controlled at 640°C, and the temperature of the fourth stage controlled at 640°C. The negative pressure of the rotary kiln is -2000Pa, and crude selenium, steamed selenium residue and crude selenium supernatant are finally obtained.

[0130] In summary, after the secondary leaching treatment, the total removal rate of copper in the copper anode mud reached 94.11%, the removal rate of arsenic was 98.31%, the removal rate of antimony was 98.43%, and the removal rate of bismuth was 98.59%.

[0131] Example 4

[0132] Take 500g of copper anode mud, the main components and their mass percentages are: Cu22.19%, Au0.1919%, Ag4.14%, As5.97%, Sb 4.43%, Bi 2.60%, Se3.38%, Te 2.05%, Pb 4.89%, Ni0.36%, Sn2.95%, Ba9.30%, Fe0.059%, Zn0.19%, Cr0.012%, Pt0.0011%, Pd0.0049, H2O35.29% and the rest are other C and O elements.

[0133] Step 100: Slurrying process: Circulating acid is added to the copper anode slime for slurrying. The acidity of the circulating acid is controlled at 220 g / L, and the amount required for each ton of copper anode slime is 1500 ml. The circulating acid is composed of sulfuric acid, sulfurous acid, and selenic acid. The slurrying time is set to 30 minutes, and the liquid-to-solid ratio is 3:1. Step 102: Primary leaching process: During the slurrying process, 500 kg of hydrochloric acid and 50 kg of sodium chloride are added per ton of copper anode slime. The reaction temperature is raised to 60°C and the reaction is continued for 3 hours. After the reaction is completed, the temperature is rapidly cooled to below 60°C, and the slurry is discharged for solid-liquid separation to obtain a primary leaching residue and a primary leaching supernatant. During this process, the copper removal rate of the copper anode slime reaches 63.35%, the arsenic removal rate is 95.98%, the antimony removal rate is 97.85%, and the bismuth removal rate is 95.78%. In step 104, the secondary leaching process, recycled acid is added to the primary leaching residue again. The acidity of the recycled acid is still controlled at 220g / L. When treating the primary leaching residue, the amount of recycled acid required for each ton of copper anode mud is 2000ml. The slurrying time is extended to 60 minutes, and the liquid-solid ratio is adjusted to 3:1. The reaction is carried out at a reaction temperature of 65°C and air is introduced for 4 hours. After the reaction is completed, the temperature is lowered to below 60°C, and solid-liquid separation is performed to obtain secondary leaching residue and secondary leaching supernatant. The secondary leaching process in step 104 achieves deep removal of copper, with a copper removal rate of 81.98%. In step 106, the secondary leaching residue is slurried with 98% concentrated sulfuric acid and then calcined in a rotary kiln. The sulfation calcination is divided into four stages: the first stage is controlled at 570°C, the second stage is controlled at 570°C, the third stage is controlled at 610°C, and the fourth stage is controlled at 610°C. The negative pressure of the rotary kiln is -1900 Pa. Finally, crude selenium, steamed selenium residue, and crude selenium supernatant are obtained.

[0134] In summary, after the secondary leaching treatment, the total removal rate of copper in the copper anode mud reached 93.21%, the removal rate of arsenic was 97.68%, the removal rate of antimony was 98.09%, and the removal rate of bismuth was 97.35%.

[0135] Example 5

[0136] Take 500g of copper anode mud, the main components and their mass percentages are: Cu23.50%, Au0.1483%, Ag4.55%, As6.0%, Sb3.86%, Bi2.82%, Se3.82%, Te1.21%, Pb5.10%, Ni0.88%, Sn1.17%, Ba8.79%, Fe0.089%, Zn0.17%, Cr0.01%, Pt0.001%, Pd0.0044, H2O31.06% and the rest are other C and O elements.

[0137] The differences from Example 1 are as follows: In step 100, the acidity of the circulating acid is controlled at 240 g / L, the amount of circulating acid added per ton of copper anode slime is 1400 ml, the slurrying time is set to 50 minutes, and the liquid-to-solid ratio is 4:1. In step 102, the primary leaching process, when treating the slurry, requires the addition of 480 kg of hydrochloric acid and 90 kg of sodium chloride per ton of copper anode slime, the reaction temperature is raised to 70°C, and the reaction is continued for 4 hours. During this process, the copper removal rate from the copper anode slime reached 65.12%, the arsenic removal rate was 96.13%, the antimony removal rate was 96.96%, and the bismuth removal rate was 95.83%. In step 104, the acidity of the circulating acid is still controlled at 240 g / L. When treating the primary leaching residue, the amount of circulating acid added per ton of copper anode slime is 2100 ml, the slurrying time is extended to 60 minutes, and the liquid-to-solid ratio is adjusted to 4:1. At a reaction temperature of 60°C, air was introduced to react for 4 hours. After the reaction was completed, the temperature was lowered to below 60°C, and solid-liquid separation was performed to obtain secondary leaching residue and secondary leaching supernatant. The secondary leaching process in step 104 achieved deep removal of copper, with a copper removal rate of 82.34%. In the sulfuric acid roasting process in step 106, the temperature of the first stage was controlled at 580°C, the temperature of the second stage was controlled at 580°C, the temperature of the third stage was controlled at 615°C, and the temperature of the fourth stage was controlled at 615°C. The negative pressure of the rotary kiln was -1800Pa.

[0138] In summary, after the secondary leaching treatment, the total removal rate of copper in the copper anode mud reached 94.19%, the removal rate of arsenic was 97.52%, the removal rate of antimony was 98.61%, and the removal rate of bismuth was 97.48%.

[0139] Example 6

[0140] Take 500g of copper anode mud, the main components and their mass percentages are: Cu23.44%, Au0.2332%, Ag5.57%, As6.44%, Sb4.31%, Bi2.74%, Se4.40%, Te2.02%, Pb5.31%, Ni0.48%, Sn1.26%, Ba5.66%, Fe0.15%, Zn0.085%, Cr0.008%, Pt0.0009%, Pd0.0044, H2O32.47% and the rest are other C and O elements.

[0141] The differences from Example 2 are as follows: in step 100, the acidity of the circulating acid was controlled at 260 g / L, the amount of circulating acid added per ton of copper anode slime was 1100 ml, the slurrying time was set to 70 minutes, and the liquid-to-solid ratio was 4:1. In step 102, during the primary leaching process, 470 kg of hydrochloric acid and 80 kg of sodium chloride were added per ton of copper anode slime to treat the slurry. The reaction temperature was raised to 75°C, and the reaction lasted for 4 hours. During this process, the copper removal rate from the copper anode slime reached 64.68%, the arsenic removal rate was 96.02%, the antimony removal rate was 96.49%, and the bismuth removal rate was 95.87%. In step 104, during the secondary leaching process, when treating the primary leaching residue, the amount of circulating acid added per ton of copper anode slime was 2300 ml, the slurrying time was extended to 70 minutes, and the liquid-to-solid ratio was adjusted to 4:1. This achieved deep copper removal, with a copper removal rate of 81.88%. In step 106, the temperature of the first stage of the sulfation roasting process is controlled at 590°C, the temperature of the second stage is controlled at 590°C, the temperature of the third stage is controlled at 620°C, the temperature of the fourth stage is controlled at 620°C, and the negative pressure of the rotary kiln is -1900Pa.

[0142] In summary, after the secondary leaching treatment, the total removal rate of copper in the copper anode mud reached 93.90%, the removal rate of arsenic was 97.65%, the removal rate of antimony was 98.91%, and the removal rate of bismuth was 98.02%.

[0143] Example 7

[0144] Take 500g of copper anode mud, the main components and their mass percentages are: Cu20.08%, Au0.1690%, Ag4.91%, As5.34%, Sb 4.02%, Bi 2.13%, Se3.41%, Te1.59%, Pb4.41%, Ni0.57%, Sn1.02%, Ba7.25%, Fe0.25%, Zn0.19%, Cr0.012%, Pt0.0017%, Pd0.0084%, H2O33.58% and the rest are other C and O elements.

[0145] The differences from Example 3 are as follows: In step 100, the acidity of the circulating acid is controlled at 280 g / L, the amount of circulating acid added per ton of copper anode slime is 1400 ml, the slurrying time is set to 75 minutes, and the liquid-to-solid ratio is 7:1. In step 102, the primary leaching process, when treating the slurry, requires the addition of 430 kg of hydrochloric acid and 100 kg of sodium chloride per ton of copper anode slime. The reaction temperature is raised to 80°C, and the reaction is continued for 5 hours. During this process, the copper removal rate from the copper anode slime reached 65.27%, the arsenic removal rate was 96.31%, the antimony removal rate was 96.58%, and the bismuth removal rate was 95.69%. In step 104, the acidity of the circulating acid is still controlled at 280 g / L. When treating the primary leaching residue, the amount of circulating acid added per ton of copper anode slime is 2400 ml, the slurrying time is extended to 50 minutes, and the liquid-to-solid ratio is adjusted to 7:1. The reaction was continued at a temperature of 75°C with air introduced for 5 hours. In step 106, the temperature of the first stage was controlled at 595°C, the temperature of the second stage was controlled at 595°C, the temperature of the third stage was controlled at 630°C, and the temperature of the fourth stage was controlled at 630°C. The negative pressure of the rotary kiln was -1500Pa.

[0146] In summary, after the secondary leaching treatment, the total removal rate of copper in the copper anode mud reached 94.26%, the removal rate of arsenic was 97.92%, the removal rate of antimony was 98.72%, and the removal rate of bismuth was 98.36%.

[0147] Example 8

[0148] Take 500g of copper anode mud, the main components and their mass percentages are: Cu21.27%, Au0.1988%, Ag5.21%, As5.70%, Sb3.30%, Bi2.02%, Se3.61%, Te1.69%, Pb6.10%, Ni0.87%, Sn2.94%, Ba7.25%, Fe0.44%, Zn0.19%, Cr0.2%, Pt0.002%, Pd0.0063, H2O32.21% and the rest are other C and O elements.

[0149] The differences from Example 1 are as follows: In step 100, the acidity of the circulating acid is controlled at 320 g / L, 1100 ml of circulating acid is added per ton of copper anode slime, the slurrying time is set to 80 minutes, and the liquid-to-solid ratio is 6:1. In step 102, during the primary leaching process, 500 kg of hydrochloric acid and 80 kg of sodium chloride are added per ton of copper anode slime. The reaction temperature is raised to 80°C and the reaction is continued for 6 hours. During this process, the copper removal rate from the copper anode slime reaches 64.88%, the arsenic removal rate is 96.15%, the antimony removal rate is 96.40%, and the bismuth removal rate is 95.55%. In step 104, during the secondary leaching process, the acidity of the circulating acid is still controlled at 320 g / L. When treating the primary leaching residue, 2000 ml of circulating acid is added per ton of copper anode slime, the slurrying time is extended to 90 minutes, and the liquid-to-solid ratio is adjusted to 6:1. The reaction was conducted at a temperature of 80°C, with air introduced, for 6 hours. The secondary leaching process in step 104 achieved deep copper removal, with a copper removal rate of 84.28%. In step 106, the sulfuric acid roasting process was conducted with the first stage temperature controlled at 600°C, the second stage temperature controlled at 600°C, the third stage temperature controlled at 640°C, and the fourth stage temperature controlled at 640°C. The negative pressure in the rotary kiln was -1600 Pa.

[0150] In summary, after the secondary leaching treatment, the total removal rate of copper in the copper anode mud reached 95.93%, the removal rate of arsenic was 97.97%, the removal rate of antimony was 98.94%, and the removal rate of bismuth was 98.76%.

[0151] Example 9

[0152] Take 500g of copper anode mud, the main components and their mass percentages are: Cu19.46%, Au0.1551%, Ag4.07%, As 6.04%, Sb4.34%, Bi2.18%, Se3.01%, Te1.27%, Pb6.60%, Ni0.77%, Sn2.17%, Ba11.37%, Fe0.0055%, Zn0.18%, Cr0.008%, Pt0.0022%, Pd0.0072, H2O28.79% and the rest are other C and O elements.

[0153] Example 9 differs from Example 1 in that: In step 100, during the slurrying process, the acidity of the circulating acid was controlled at 380 g / L, and the amount of circulating acid added per ton of copper anode slime was 1500 ml. The slurrying time was set to 100 minutes, and the liquid-to-solid ratio was 7:1. In step 102, during the primary leaching process, 450 kg of hydrochloric acid and 80 kg of sodium chloride were added per ton of copper anode slime to treat the slurry. The reaction temperature was raised to 90°C, and the reaction lasted for 8 hours. During this process, the copper removal rate from the copper anode slime reached 65.11%, the arsenic removal rate was 98.24%, the antimony removal rate was 97.16%, and the bismuth removal rate was 96.12%. In step 104, during the secondary leaching process, the acidity of the circulating acid was still controlled at 380 g / L. When treating the primary leaching residue, the amount of circulating acid added per ton of copper anode slime was 2500 ml. The slurrying time was extended to 100 minutes, and the liquid-to-solid ratio was adjusted to 8:1. The reaction was conducted at a temperature of 90°C, with air introduced, for 8 hours. The secondary leaching process in step 104 achieved deep copper removal, with a copper removal rate of 86.36%. In step 106, the sulfuric acid roasting process was conducted with the first stage temperature controlled at 620°C, the second stage temperature controlled at 620°C, the third stage temperature controlled at 660°C, and the fourth stage temperature controlled at 660°C. The rotary kiln negative pressure was maintained at -2500 Pa.

[0154] In summary, after the secondary leaching treatment, the total removal rate of copper in the copper anode mud reached 96.94%, the removal rate of arsenic was 99.06%, the removal rate of antimony was 98.83%, and the removal rate of bismuth was 99.11%.

[0155] Example 10

[0156] Take 500g of copper anode mud, the main components and their mass percentages are: Cu24.24%, Au0.2675%, Ag5.63%, As5.73%, Sb5.00%, Bi1.91%, Se5.10%, Te2.83%, Pb4.10%, Ni1.07%, Sn1.22%, Ba6.03%, Fe0.079%, Zn0.23%, Cr0.012%, Pt0.0015%, Pd0.0058, H2O31.79% and the rest are other C and O elements.

[0157] The differences from Example 2 are: the acidity of the circulating acid is controlled at 350 g / L, the amount of circulating acid added per ton of copper anode slime is 1400 ml, the slurrying time is set to 90 minutes, and the liquid-to-solid ratio is 6:1. In step 102, the primary leaching process, during the slurrying process, 450 kg of hydrochloric acid and 75 kg of sodium chloride are added per ton of copper anode slime. The reaction temperature is raised to 85°C, and the reaction is continued for 5 hours. During this process, the copper removal rate from the copper anode slime reached 65.09%, the arsenic removal rate was 97.03%, the antimony removal rate was 96.56%, and the bismuth removal rate was 95.81%. In step 104, the secondary leaching process, the acidity of the circulating acid is still controlled at 350 g / L, the amount added is 2600 ml, the slurrying time is extended to 90 minutes, and the liquid-to-solid ratio is adjusted to 6:1. The reaction is carried out at a reaction temperature of 85°C, with air introduced, for 7 hours. In step 104, the secondary leaching process achieves deep removal of copper, with a copper removal rate of 85.16%. In step 106, the sulfuric acid roasting process, the temperature of the first stage is controlled at 620°C, the temperature of the second stage is controlled at 620°C, the temperature of the third stage is controlled at 650°C, and the temperature of the fourth stage is controlled at 650°C. The negative pressure of the rotary kiln is -1800Pa.

[0158] In summary, after the secondary leaching treatment, the total removal rate of copper in the copper anode mud reached 96.19%, the removal rate of arsenic was 98.26%, the removal rate of antimony was 98.54%, and the removal rate of bismuth was 98.81%.

[0159] Example 11

[0160] Take 500g of copper anode mud, the main components and their mass percentages are: Cu21.46%, Au0.1459%, Ag4.64%, As 6.07%, Sb4.13%, Bi4.83%, Se3.99%, Te2.66%, Pb6.24%, Ni0.68%, Sn2.78%, Ba3.47%, Fe0.14%, Zn0.047%, Cr0.01%, Pt0.0010%, Pd0.0041, H2O30.82% and the rest are other C and O elements.

[0161] This method differs from Example 2 in that, in step 100, the acidity of the circulating acid is controlled at 260 g / L, the amount of circulating acid required per ton of copper anode slime is 1300 ml, the slurrying time is set to 100 minutes, and the liquid-to-solid ratio is 7:1. In step 102, the primary leaching process, during the slurrying process, 490 kg of hydrochloric acid and 90 kg of sodium chloride are added per ton of copper anode slime. The reaction temperature is raised to 90°C, and the reaction is continued for 7 hours. During this process, the copper removal rate from the copper anode slime reached 65.11%, the arsenic removal rate was 98.24%, the antimony removal rate was 97.16%, and the bismuth removal rate was 96.12%. In step 104, the secondary leaching process, the acidity of the circulating acid is still controlled at 260 g / L. When treating the primary leaching residue, the amount of circulating acid required per ton of copper anode slime is 2100 ml, the slurrying time is extended to 100 minutes, and the liquid-to-solid ratio is adjusted to 8:1. The reaction was conducted at a temperature of 90°C, with air introduced, for 8 hours. The secondary leaching process in step 104 achieved deep copper removal, with a copper removal rate of 86.36%. In step 106, the sulfuric acid roasting process was conducted with the first stage temperature controlled at 630°C, the second stage temperature controlled at 630°C, the third stage temperature controlled at 650°C, and the fourth stage temperature controlled at 650°C. The rotary kiln negative pressure was maintained at -2700 Pa.

[0162] In summary, after the secondary leaching treatment, the total removal rate of copper in the copper anode mud reached 96.94%, the removal rate of arsenic was 99.06%, the removal rate of antimony was 98.83%, and the removal rate of bismuth was 99.11%.

[0163] Comparative Example 1

[0164] Compared with Example 1, the difference of Comparative Example 1 is that the circulating acid in the step of Comparative Example 1 is directly replaced with a sulfuric acid solution of equal acidity, and the remaining steps are the same as those of Example 1, thereby obtaining a total copper removal rate of 86.24%, an arsenic removal rate of 95.25%, an antimony removal rate of 94.58%, and a bismuth removal rate of 96.19% in the copper anode mud.

[0165] Comparative Example 2

[0166] Compared with Example 1, the difference of Comparative Example 2 is that, in Comparative Example 1, the circulating acid in the step is directly replaced with a sulfurous acid solution of equal acidity, and the remaining steps are uniformly the same as Example 1, resulting in a total copper removal rate of 85.58%, an arsenic removal rate of 94.98%, an antimony removal rate of 93.58%, and a bismuth removal rate of 95.18% in the copper anode mud.

[0167] Comparative Example 3

[0168] Compared with Example 1, the difference of Comparative Example 3 is that, in Comparative Example 1, the circulating acid in the step is directly replaced by a mixed solution of sulfuric acid and sulfurous acid with equal acidity, and the remaining steps are uniformly the same as Example 1, and a total copper removal rate of 86.17%, an arsenic removal rate of 95.47%, an antimony removal rate of 94.37%, and a bismuth removal rate of 95.47% in the copper anode mud are obtained.

[0169] Comparative Example 4

[0170] The copper anode mud was added to the selenium-containing acidic solution, and 30% concentrated hydrochloric acid was added for primary leaching. The liquid-solid ratio was controlled to be 2:1, the reaction temperature was 70°C, and the chloride ion concentration was 120g / L. After the reaction time was 3 hours, the leaching solution contained Cu25.9g / L, Sb25.6g / L, Bi14.6g / II, Te0.03g / L, and Se<0.5g / L. The primary leaching residue was added to the selenium-containing acidic solution for secondary leaching. The liquid-solid ratio was controlled to be 3:1, the reaction temperature was 70°C, 0.4MPa compressed air was introduced for 1 hour, and the reaction was continued for 2 hours and filtered. The secondary leaching solution contained Cu65.2g / L, Sb5.7g / L, Bi 3.9g / L, Te 0.27g / L, Se <0.5g / L; the selenium-containing acidic solution contains 3.5g / L selenium, 266g / L H2SO4, and 28.5g / L chloride ions; the secondary leaching residue is slurried in 98% concentrated sulfuric acid at a mass ratio of 0.9 to concentrated sulfuric acid for 0.5 hours, then added to a rotary kiln for sulfuric acid calcination at a temperature of 500-700°C for 2 hours; the resulting calcine contains 0.06% selenium; the flue gas is subjected to three-stage absorption in an absorption tower, stirred at room temperature for another 10 hours, and filtered to obtain crude selenium containing 88% selenium and a selenium-containing acidic solution. The selenium-containing acidic solution is returned to the above leaching process for reuse. In this embodiment, the total copper removal rate in the final copper anode mud reaches 56%, the arsenic removal rate is 94.35%, the antimony removal rate is 88%, and the bismuth removal rate is 90%.

[0171] The difference between Comparative Example 5 and Comparative Example 4 is that:

[0172] The liquid-solid ratio was controlled to be 3:1, the chloride ion concentration was 130 g / L, the reaction time was 4 hours and then filtered, the primary leachate contained Cu34.1 g / L, Sb28.5 g / L, Bi15.0 g / II, Te0.02 g / L; after passing 0.4 MPa compressed air for 1.5 hours, the reaction was continued for 3 hours and then filtered, the secondary leachate contained Cu54.7 g / L, Sb6.5 g / L, Bi5.1 g / L, Te0.34 g / L; the selenium in the above selenium-containing acidic solution was 2.9 g / L, H2SO4 is 320g / L, and chloride ion is 25.3g / L; according to the mass ratio of secondary leaching residue to concentrated sulfuric acid of 0.8, 98% concentrated sulfuric acid is added to slurry for 1 hour, and then the secondary leaching residue is added to a rotary kiln for sulfuric acid roasting for 2.5 hours; the flue gas is absorbed by a three-stage absorption tower, stirred for another 12 hours at room temperature, and filtered to obtain crude selenium containing 87% selenium and a selenium-containing acidic solution. The selenium-containing acidic solution is returned to the above leaching process for reuse, and the roasted selenium content is 0.07%. In this embodiment, the total copper removal rate in the copper anode mud reaches 60%, the arsenic removal rate is 93.56%, the antimony removal rate is 90%, and the bismuth removal rate is 91%.

[0173] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A method for circulating acid leaching of copper anode mud, characterized in that: The following steps are involved: Slurrying process: put the copper anode mud into the pre-slurrying reaction tank, add circulating acid into the pre-slurrying reaction tank for slurrying treatment, the acidity of the circulating acid is 200-400g / L, and the amount is 1.0-1.5m 3 / t copper anode slime, the slurrying time is 20min-120min, and the liquid-to-solid ratio is controlled at 2:1-8:1 to obtain a slurry liquid, wherein the circulating acid is composed of sulfuric acid, sulfurous acid and selenic acid, and the ratio of the sulfuric acid, the sulfurous acid and the selenic acid is 4:2:1-6:2:1; Primary leaching process: putting the slurry into a primary leaching reaction tank, adding hydrochloric acid and sodium chloride into the primary leaching reaction tank for primary leaching, wherein the amount of the hydrochloric acid is 400-500 kg / t of copper anode mud, the amount of the sodium chloride is 50-100 kg / t of copper anode mud, the reaction temperature is 60° C.-95° C., the reaction time is 1 hour-8 hours, after the reaction is completed, cooling to 50° C.-60° C. and then performing solid-liquid separation, after solid-liquid separation, obtaining primary leaching residue and primary leaching supernatant, and retaining the primary leaching supernatant; Secondary leaching process: add the circulating acid again to the primary leaching residue, the acidity of the circulating acid is 200-400 g / L, and the amount is 2-3 m 3 / t copper anode mud, the liquid-solid ratio is controlled at 2:1-8:1, the slurrying time is 30min-60min, the reaction temperature is 65-95°C, the reaction time is 3h-10h, after the reaction is completed, the temperature is lowered to 55°C-60°C, air is introduced, and the temperature is raised for secondary leaching, after solid-liquid separation, secondary leaching residue and secondary leaching supernatant are obtained, the secondary leaching supernatant and the primary leaching supernatant are purified to obtain purified slag, and copper, arsenic, antimony and bismuth therein are recovered; Sulfate roasting process: the secondary leaching residue is slurried with concentrated sulfuric acid, the secondary leaching residue is mixed with the concentrated sulfuric acid to form a slurry, and the slurry is sent to a rotary kiln for sulfate roasting. The sulfate roasting is divided into four stages, and the temperatures of the four stages are 560-620°C, 580-620°C, 620-660°C, and 620-660°C, respectively. The time of each stage is the same, and the negative pressure of the rotary kiln is controlled at 3000-1500Pa to obtain crude selenium, steamed selenium residue and crude selenium supernatant, wherein the crude selenium supernatant is returned to the slurrying process and the secondary leaching process as the circulating acid.

2. The method for circulating acid leaching of copper anode mud according to claim 1, characterized in that: The purity of the concentrated sulfuric acid in the sulfuric acid roasting step is ≥98%, and the ratio of the amount of the concentrated sulfuric acid to the weight of the secondary leaching residue is 0.6-1.

8.

3. The method for circulating acid leaching of copper anode mud according to claim 1, characterized in that: The time of each roasting stage is 30 minutes to 37.5 minutes.

4. The method for circulating acid leaching of copper anode mud according to claim 1, characterized in that: The secondary leaching process, wherein the secondary leaching supernatant and the primary leaching supernatant are purified to obtain purified slag, comprises: After the secondary leaching supernatant and the primary leaching supernatant are mixed, liquid alkali is added to adjust the pH value to 3.5 to obtain purified slag.

5. The method for circulating acid leaching of copper anode mud according to claim 1, characterized in that: The copper anode mud comprises the following components: copper, gold, silver, arsenic, antimony, bismuth, selenium, tellurium, lead, nickel, tin, barium, iron, zinc, chromium, platinum, palladium, water, carbon and oxygen.

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