Process for the capture of gold in lead anode slime by antimony reinforced bismuth

Abstract

The application provides a method for capturing gold in lead anode slime by antimony reinforced bismuth, and belongs to the technical field of resource comprehensive utilization; on the basis of capturing gold and silver by lead bismuth, antimony is added to reinforce the effect of capturing gold by bismuth; through theoretical calculation, antimony atoms doped on the surface of bismuth can enhance the adsorption strength of gold atoms, and reinforce the effect of capturing gold by bismuth; therefore, the application develops a method for mixing lead anode slime, crude lead and crude antimony according to a certain proportion to obtain noble lead through reduction smelting, obtaining gold and silver alloy through oxidation and impurity removal of the noble lead, obtaining crude silver and crude gold through vacuum distillation of the gold and silver alloy, and obtaining high-purity silver and gold through electrolysis of the crude silver and the crude gold; compared with the method without adding crude antimony, the recovery rate of silver and gold is improved; by increasing the content of antimony in the noble lead, reducing the loss of gold in the reduction smelting process, and cooperatively smelting crude bismuth and crude antimony, the recovery rate of bismuth and antimony is improved, and efficient recovery and utilization of rare and precious metals in lead anode slime is realized.

Description

Technical Field

[0001] This invention relates to the field of comprehensive resource utilization technology, specifically to a method for capturing gold from lead anode mud using antimony-enhanced bismuth. Background Technology

[0002] Lead anode slime, an inevitable byproduct of crude lead electrolytic refining, is the primary source of gold and silver recovery in the primary and recycled lead industry chain. More than half of China's silver production and a significant proportion of its gold production come from the comprehensive recovery of lead anode slime. The core objective of this treatment is to efficiently separate, enrich, and purify the gold and silver present in the anode slime, while simultaneously recovering associated valuable metals such as copper, antimony, bismuth, and tellurium, achieving full resource utilization and maximizing benefits. Currently, the mainstream lead anode slime treatment processes in the industry include "traditional pyrometallurgical," "fully hydrometallurgical," "pyrometallurgical-hydrometallurgical combined," and "beneficiation-metallurgical combined." These various processes differentiate themselves based on gold and silver recovery efficiency, product purity, environmental friendliness, and raw material adaptability. Traditional pyrometallurgical processes are the earliest and most mature classic processes used in lead anode mud treatment. The core process revolves around "high-temperature reduction smelting - oxidation blowing - electrolytic refining," focusing on the deep enrichment and efficient recovery of gold and silver. Its core advantages are: extremely high raw material adaptability, capable of processing complex lead anode mud with high arsenic, high antimony, and large compositional fluctuations; initial enrichment of gold and silver can be achieved without complex pretreatment processes; large processing scale and continuous, stable operation, suitable for large-scale production in large smelters, enabling batch recovery of gold and silver; the high-temperature smelting process can achieve a hundredfold enrichment of gold and silver in a single operation; the process is intuitive, operation and control are simple, with low dependence on equipment and reagents; outstanding production stability and risk resistance; high comprehensive gold and silver recovery rate; effective reduction of gold and silver dispersion losses; and mature technology suitable for large-scale industrial promotion.

[0003] The all-wet process uses "room temperature / medium-low temperature liquid phase leaching - separation - reduction" as its core flow, without any high-temperature smelting steps. It represents a clean route for gold and silver recovery. Its core process is "pretreatment and impurity removal - precious metal leaching - metal recovery": In the pretreatment stage, copper is selectively leached with acid to avoid interference with subsequent gold and silver leaching; then, selenium / tellurium is removed through an alkaline oxidation system to further purify the raw material system; in the precious metal leaching stage, gold is efficiently extracted using a chlorination system, while silver is specifically recovered using thiourea or cyanide methods. The metals are finally separated and purified through chemical reduction and electrolytic refining. Its core advantage lies in: gold... It boasts high silver recovery rate and stable direct recovery rate with minimal metal dispersion loss. The direct recovery rate of silver can reach over 98%, and that of gold over 97%. The entire process involves low-temperature liquid-phase reaction, generating no high-temperature flue gas or dust, resulting in a cleaner working environment and less environmental pressure. It also offers excellent targeted separation of impurities, allowing for the segmented recovery of associated valuable metals such as copper, selenium, and tellurium, leading to a high degree of comprehensive resource utilization. The equipment requires moderate investment, has a compact layout, and is relatively easy to operate, making it suitable for small to medium-sized production lines with stable raw material grades. It is also suitable for promotion in areas with high environmental protection requirements. However, it has drawbacks such as strong dependence on toxic reagents, high wastewater treatment costs, and limited adaptability to high-arsenic and antimony raw materials.

[0004] The core process of the pyrometallurgical-hydrometallurgical combined process is as follows: First, the precious metals in the lead anode mud are enriched and volatile impurities such as As / Sb are removed through reduction smelting to obtain precious lead or gold and silver concentrates; then, through hydrometallurgical processes such as nitric acid silver separation, chlorination gold extraction and electrolytic refining, the gold and silver are efficiently separated and purified. Its core advantages are: the pyrometallurgical stage can quickly achieve deep enrichment of gold and silver, significantly reducing the material volume and reagent consumption of subsequent hydrometallurgical treatment and improving processing efficiency; high-temperature pre-removal can significantly improve the raw material conditions of the hydrometallurgical process and reduce the interference of impurities on the leaching and purification of gold and silver. However, it has disadvantages such as complex process, high investment cost and high facility requirements.

[0005] The core process of the combined beneficiation and smelting process is "mineral processing pretreatment - pyrometallurgical smelting - hydrometallurgical refining": In the pretreatment stage, pH control and selective flotation are used to achieve efficient separation of precious and base metals, removing most gangue and useless impurities. Gravity separation is used to further enrich precious metals and significantly improve the grade of gold and silver in the raw materials. In the pyrometallurgical stage, reduction smelting and oxygen top blowing processes are used to effectively remove impurities such as lead, arsenic, and antimony, and further enrich gold and silver. The hydrometallurgical refining process includes electrolysis of the silver nitrate system and solvent extraction to extract gold, achieving the final purification of gold and silver. It has disadvantages such as long process flow, complex steps, high environmental protection requirements, and large reagent consumption. Summary of the Invention

[0006] To address the problems existing in related technologies, this invention provides a method for capturing gold from lead anode mud using antimony-enhanced bismuth. By increasing the antimony content in precious lead and reducing gold loss during the reduction smelting process, this method aims to improve the recovery rate of gold, antimony, and bismuth, achieving efficient recycling of rare and precious metals from lead anode mud. The specific steps are as follows: (1) After mixing lead anode mud, crude bismuth and crude antimony, reducer coal and soda ash are added for reduction smelting to obtain precious lead, reducing slag and antimony-containing flue ash.

[0007] (2) The precious lead is subjected to oxidation and impurity removal process to obtain arsenic-antimony alloy, oxide slag and antimony-containing flue dust.

[0008] (3) The arsenic-antimony alloy is subjected to oxidation and impurity removal intermediate to obtain arsenic-antimony-lead-bismuth alloy, oxide slag and dry slag.

[0009] (4) Add soda ash to the arsenic-antimony-lead-bismuth alloy, and obtain sodium tellurate slag and gold-silver alloy after oxidation and impurity removal.

[0010] (5) The gold-silver alloy is smelted in a vacuum to obtain crude silver and crude gold.

[0011] (6) Silver and gold are recovered by electrowinning.

[0012] (7) Add the antimony-containing flue ash obtained in steps (1) and (2) to reducing coal and soda ash to recover crude antimony.

[0013] (8) Add the oxidized residue obtained in steps (2) and (3) to reducing coal and soda ash for crude bismuth recovery.

[0014] (9) The sodium tellurate residue obtained in step (4) is subjected to alkaline leaching, solid-liquid separation, sulfide precipitation and electrowinning to recover tellurium.

[0015] Further, in step (1) of this invention, the lead anode mud comprises the following components by mass percentage: Pb 25%~40%, Bi 10%~20%, Ag 5%~15%, Cu 1%~2%, Sb 20%~40%, As 3~5%, Au 0.02%~0.5%, and Te <1%, with the total mass percentage of the components being 100%; the crude bismuth comprises the following components by mass percentage: Bi 75%~89.9%, Pb 10%~25%, and Ag 0.1%~0.5%. The total mass percentage of the components is 100%; the crude antimony includes the following components by mass percentage: Sb 90%~98%, As 1%~8% and Pb 1%~2%; wherein the mass ratio of lead anode mud, crude bismuth and crude antimony is 10:(2-4):(1-2); and the reduction smelting conditions are: temperature 1200~1300℃, time 3~8h, adding 3~8% of the raw material mass of reducing coal and 5~10% of the raw material mass of soda ash, wherein the reducing coal is coke and the soda ash is sodium carbonate.

[0016] Furthermore, the conditions for the initial stage of oxidation and impurity removal in step (2) of the present invention are: temperature 800~900℃, and time until oxidation slag is generated.

[0017] Furthermore, the conditions for the intermediate stage of oxidation and impurity removal in step (3) of the present invention are: temperature 900~1000℃, time until oxidation slag stops being generated and dry slag is generated.

[0018] Furthermore, the conditions for the later stage of oxidation and impurity removal in step (4) of the present invention are as follows: later stage of oxidation and impurity removal: temperature 1000~1100℃, time 3~8h, and soda ash of 1~3% of the mass of precious lead is added.

[0019] Furthermore, the process parameters for vacuum melting in step (5) of the present invention are: vacuum degree 5~20Pa, temperature 1000~1200℃, and distillation time 8~15h.

[0020] Furthermore, the electrolysis process parameters in step (6) of the present invention are as follows: using crude silver as the anode, silver is recovered in an electrolyte containing silver nitrate, wherein the concentration of nitric acid in the electrolyte is 20~30 g / L and Ag + The concentration is 55~65 g / L, and the current density is 200~300 A / m. 2 The temperature is 45~55℃, the cell voltage is 1.8~2.2V, the electrode spacing is 76~86mm, and gelatin is added; crude gold is used as the anode, and gold is recovered in an electrolyte containing chloroauric acid, wherein Au in the electrolyte is... 3+ The concentration is 50~70 g / L, the HCl concentration is 70~90 g / L, and the current density is 300~400 A / m. 2 The cell voltage is 1~2.5V, the electrolysis temperature is 50~60℃, and the electrode spacing is 70~80mm.

[0021] Furthermore, the crude antimony recovery process parameters in step (7) of the present invention are: temperature 1200~1300℃, time 3~8h, reducing coal dosage 2~6% of the ash mass, and soda ash dosage 2~5% of the ash mass.

[0022] Furthermore, the crude bismuth recovery process parameters in step (8) of the present invention are as follows: 1-5% of soda ash by mass of oxidized slag, 5-15% of reducing coal by mass of oxidized slag, temperature of 750-1000℃, and time of 2-7h.

[0023] Further, the tellurium recovery process parameters in step (9) of this invention are as follows: sodium tellurate slag is leached with a sodium hydroxide solution of concentration 40~80 g / L, the leaching temperature is 60~90℃, the liquid-solid ratio of sodium tellurate slag to sodium hydroxide solution is (2:1)~(4:1), the leaching time is 4~8h, after leaching the solid and liquid are separated, and sodium sulfide is used for sulfidation precipitation, the ratio of sodium sulfide to sodium tellurate slag is (0.01~0.05):1, the reaction temperature is 60~90℃; the tellurium concentration is 40~250 g / L, the free sodium hydroxide concentration is 60~120 g / L, and the current density is 30~70 A / m 2 Tellurium is recovered after electrowinning under the conditions of cell voltage 1.4~2.6V, electrolysis temperature 45~60℃, and electrolysis cycle 36~80 hours.

[0024] Beneficial effects of this invention: (1) The method for capturing gold in lead anode mud by antimony-enhanced bismuth provided by the present invention achieves efficient recovery of gold and silver and targeted recovery of valuable metals such as bismuth, antimony and tellurium through synergistic reduction smelting of lead anode mud, crude bismuth and crude antimony, staged oxidation and impurity removal, vacuum refining and electrolytic purification. The process is compact and the resource utilization rate is high. The gold recovery rate is higher than that of the process without adding crude antimony, by about 4.97~7.8%; the silver recovery rate is increased by about 3.4~3.45% at the same time.

[0025] (2) The lead anode mud, crude bismuth and crude antimony are processed in a pyrometallurgical system, which reduces equipment investment. Through precise temperature control, the stepwise separation of As, Sb, Pb, Bi and Te is achieved. The antimony recovery system in flue ash and the bismuth recovery system in oxide slag not only recover valuable metals in a targeted manner, but also avoid the accumulation of impurities in gold and silver alloys.

[0026] (3) Reduce the volatilization and mechanical loss of gold and silver during reduction smelting and oxidation impurity removal, especially reduce the dispersion loss of gold during the oxidation stage. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the Bi(001) surface structure in Embodiment 1 of the present invention, wherein... Figure 1 (a) is a schematic diagram of the surface structure of Bi(001); Figure 1 (b) shows possible adsorption sites on the Bi(001) surface.

[0028] Figure 2 This is an atomic structure diagram of Au atoms adsorbed on the Bi(001) surface in Example 1 of the present invention, wherein... Figure 2 (a) shows the most stable atomic structure of Au atoms adsorbed on the Bi(001) surface. Figure 2 (b) represents the 2D charge density. Figure 2 (c) represents the partial density of states. Figure 2 (d) represents the differential charge density.

[0029] Figure 3 This refers to the atomic structure of Bi(001) surface doped with different atoms in Embodiment 1 of the present invention, wherein... Figure 3 (a) shows the atomic structure of Bi(001) surface doped with different atoms. Figure 3 (b) are possible adsorption sites.

[0030] Figure 4 It is the adsorption energy of gold atoms on different atomic-doped B (001) surfaces in Embodiment 1 of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings, but the scope of protection of the present invention is not limited to the content described.

[0032] Example 1 The specific steps for studying the adsorption behavior of gold atoms on the bismuth surface and the enhancing effect of antimony atoms on the adsorption of gold by bismuth are as follows: (1) A Bi(001) supercell surface with a thickness of 6 layers and a size of 3×3×1 was constructed using the bismuth atomic layer structure Bi(001), and a 15 Å vacuum layer was added in its Z direction, as shown in the figure. Figure 1 As shown in (a); during the geometry optimization process, the bottom four layers of atoms are fixed to simulate bulk phase characteristics, while the top two layers of Bi atoms are fully relaxed; the top view of the fully relaxed surface structure is shown below. Figure 1 As shown in Figure b, four different highly symmetric adsorption sites exist on this surface: Bitop sites, Subtop sites, Hollow sites, and Bridge sites. Therefore, during the simulated adsorption process, Au atoms were placed 2.5 Å above these adsorption sites and allowed to fully relax. Subsequently, the adsorption energies of different adsorption systems were calculated, and the results are shown in Table 1. The results indicate that the adsorption energy range of gold atoms on the Bi(001) surface is [insert range here]. 1.75eV to 2.36 eV, where Au atoms move to the Hollow site after relaxation at the Bridge site, and the adsorption energy at the Hollow site is the highest. (2.36 eV); therefore, gold atoms preferentially adsorb at the Hollow site.

[0033] Table 1 Adsorption energies of gold atoms at different adsorption sites on the Bi(001) surface. Figure 2a represents the most stable structure of Au atoms adsorbed on the Bi(001) surface. As shown in the figure, the distances between the Au atom and the three adjacent Bi atoms are 2.914 Å, 2.915 Å, and 2.915 Å, respectively, all of which are less than the sum of their theoretical atomic radii (rAu+rBi=3.170 Å). This indicates that the Au atom has a strong interaction with the three neighboring Bi atoms during the adsorption process, and thus is stably adsorbed on the Bi(001) surface. In addition, combined with the large adsorption energy result, we can speculate that the gold atoms are firmly adsorbed on the Bi(001) surface through Au-Bi chemical bonds.

[0034] (2) To further investigate the interaction mechanism between Au atoms and the Bi(001) surface, the two-dimensional charge density distribution, fractional state density, and differential charge density plot of the adsorption system were calculated in this embodiment. The results are as follows: Figure 2 As shown in (bc), by Figure 2 (b) It can be seen that Au and Bi have a large number of electrons gathered around them, and there is a slight overlap of electron clouds between Au atoms and neighboring Bi atoms, indicating that Au and Bi atoms share some electrons. It can be inferred that they form Au-Bi metallic bonds by sharing outer electrons; Figure 2 As shown in d, a significant electron-gathering region appears around the Au atom, while the region around the neighboring Bi atom exhibits electron-dissipation. Furthermore, the Au atom gains electrons of 0.459 eV from each of the three Bi atoms, indicating an ionic bond between Au and Bi. Additionally, as... Figure 2 As shown in (c), the interaction between Au and Bi is mainly attributed to the hybridization between the Au-5d and Bi-6p orbitals; specifically, in 4.30 to Significant hybridization occurred in the Au-5d and Bi-6p orbitals in the low energy range of 2.00 eV, particularly in... A strong resonance peak appeared at 3.45 eV. This orbital hybridization led to the formation of Au-Bi metallic bonds, which also explains why the Bi(001) surface has a large adsorption strength for Au atoms.

[0035] (3) As, Sb, Pb, Si and Na atoms were doped into Bi(001) respectively, and the results are as follows: Figure 3 The doped Bi(001) surface shown has five highly symmetric adsorption sites: Doptop, Subtop, Top, Bridge, and Hollow. Geometric optimization of the adsorption sites of gold atoms in different doping systems yielded the adsorption energies of the corresponding lowest energy structures, as shown in the figure. Figure 4 As shown, it can be seen that compared to the adsorption energy when undoped ( Sb doping enhances the adsorption strength of Au atoms, increasing the adsorption energy to 2.36 eV. 2.59 eV; Si and Na doping also enhanced the adsorption strength of Au atoms, increasing the adsorption energy to -3.12 eV and -2.37 eV, respectively. However, doping Si and Na atoms into the raw material will inevitably introduce silicon dioxide and sodium oxide, which is not conducive to the subsequent impurity removal process. As and Pb doping both enhance the adsorption of Au atoms, but their adsorption energies are lower than those of Sb atoms. Therefore, this paper chooses to add crude antimony (whose main component is Sb2O3) to the raw material to investigate the effect of Sb in enhancing gold capture.

[0036] Example 2 A method for capturing gold from lead anode mud using antimony-enhanced bismuth comprises the following steps: The reducing coal (coke) and soda ash (sodium carbonate) used in this invention are both sourced from Guangdong Xilong Scientific Co., Ltd.

[0037] (1) Lead anode mud, crude bismuth, and crude antimony were mixed in a mass ratio of 10:2:2 to obtain a mixed raw material. The components and mass percentages of the lead anode mud were Pb 30.22%, Bi 18.44%, Ag 13.22%, Cu 1.5%, Sb 32.5%, As 3.04%, Au 0.42%, and Te 0.66%. The components and mass percentages of the crude bismuth were Bi 83.22%, Pb 16.44%, and Ag 0.34%. The components and mass percentages of the crude antimony were Sb 95.23%, As 3.55%, and Pb 1.22%. After mixing, the mixture is loaded into a reduction furnace for reduction smelting. Simultaneously, 6% by weight of coke and 8% by weight of sodium carbonate are added to the furnace. The temperature is controlled at 1250℃, and smelting is carried out for 5 hours to obtain precious lead, reducing slag, and antimony-containing flue dust. The components in the precious lead, by mass percentage, are: Pb 24.69%, Bi 26.22%, Ag 9.45%, Cu 1.07%, Sb 35.11%, As 2.69%, Te 0.48%, and Au 0.29%. After the reducing slag is poured out, the remaining precious lead is fed into an oxidation furnace via a ladle, and the antimony-containing flue dust is collected using a bag filter.

[0038] (2) Preliminary oxidation and impurity removal: The obtained precious lead is added to the oxidation furnace and the temperature is controlled at 850℃. The time is until a small amount of oxidation slag is produced, and arsenic-antimony alloy, oxidation slag and antimony-containing flue dust are obtained. The oxidation slag is scooped out and the antimony-containing flue dust is collected by a bag filter. The composition of the obtained antimony-containing flue dust is arsenic oxide, antimony oxide and lead oxide.

[0039] (3) Mid-term oxidation and impurity removal: The arsenic-antimony alloy continues in the oxidation furnace, with the temperature controlled at 950℃. The time is until the oxidation slag stops being generated and dry slag begins to be generated. At this time, the arsenic-antimony lead-bismuth alloy, oxidation slag and dry slag are obtained. The oxidation slag and dry slag are then retrieved.

[0040] (4) Post-oxidation and impurity removal: The arsenic-antimony-lead-bismuth alloy continues to be in the oxidation furnace, with the temperature controlled at 1050℃. Sodium carbonate of 2% of the mass of the precious lead in step (2) is added, and the reaction time is 8h. Sodium tellurate slag and gold-silver alloy are obtained. The sodium tellurate slag is collected by scooping, and the gold-silver alloy is poured into the ladle. The gold-silver alloy contains 97.3% silver by mass, 1.81% gold by mass, and 0.89% other impurities.

[0041] (5) The gold-silver alloy obtained in step (4) is placed in a continuous vacuum furnace for vacuum melting. The conditions are: vacuum degree controlled at 20 Pa, temperature at 1200 °C, and distillation time at 12 h to obtain crude silver volatiles and crude gold residue. The crude silver volatiles contain 99.11% silver by mass and the crude gold residue contains 90.23% gold by mass.

[0042] (6) Recovery of gold and silver by electrowinning: using crude silver as the anode and a pure silver plate as the cathode, electrolysis is carried out in a silver nitrate electrolyte with a nitric acid concentration of 20 g / L and a current density of 200 A / m. 2 Temperature 45℃, Ag + With a concentration of 55 g / L, a cell voltage of 2.2 V, an electrode spacing of 86 mm, a diaphragm bag between the cathode and anode, and 1 g / L gelatin added to the electrolyte, silver precipitates as powder at the cathode under these conditions, with a purity of 99.95%. Using crude gold as the anode and pure gold sheets as the cathode, electrolysis is carried out in a chloroauric acid electrolyte, wherein the electrolyte contains Au... 3+ The concentration is 50 g / L, the free HCl concentration is 90 g / L; the current density is 300 A / m. 2 The cell voltage is 1V; the electrolysis temperature is 60℃ and the electrode spacing is 70mm. Under these conditions, gold is densely deposited at the cathode with a purity of 99.96%. After the electrolysis process, high-purity silver and gold are obtained and can be sold directly. The recovery rates of silver and gold are 98.63% and 97.22%, respectively.

[0043] (7) The antimony-containing flue dust obtained in steps (1) and (2) is sent to the crude antimony smelting process for crude antimony recovery. The crude antimony smelting conditions are as follows: sodium carbonate containing 4% by mass of antimony flue dust and coke containing 4% by mass of antimony flue dust are added, the furnace temperature is controlled at 1250℃, and the time is 6h to obtain crude antimony. The mass percentage of antimony in the crude antimony is 94%, which can be used for reduction smelting or sold directly.

[0044] (8) The oxide slag obtained in steps (2) and (3) is sent to the crude bismuth smelting process for crude bismuth recovery. The crude bismuth smelting conditions are: 3% sodium carbonate by mass of oxide slag and 10% coke by mass of oxide slag are added, the temperature is 900℃, and the time is 6h to obtain crude bismuth. The mass percentage of bismuth in the crude bismuth is 85%, which can be used for synergistic reduction smelting of lead anode mud.

[0045] (9) The sodium tellurate slag obtained in step (4) is sent to the tellurate comprehensive recycling workshop for tellurate recovery. The tellurate recovery conditions are as follows: the sodium tellurate slag is first leached in a sodium hydroxide solution with a concentration of 50 g / L, the leaching temperature is 90℃, the liquid-solid ratio of sodium hydroxide solution to sodium tellurate slag is 4:1, and the leaching time is 4h, so that tellurium enters the solution in the form of sodium tellurite (Na2TeO3); after leaching, solid-liquid separation is performed, and sodium sulfide is added to the obtained leachate. Sodium sulfide (Na₂S) is used for purification to precipitate heavy metal impurities such as copper and lead. The mass ratio of sodium sulfide to sodium tellurate slag is 0.02:1, the reaction temperature is 70℃, and the reaction continues until the precipitate is completely formed. After filtration, a pure tellurium-containing solution is obtained. Finally, the tellurium-containing solution is sent to an electrolytic cell for electrowinning. The electrowinning conditions are controlled as follows: tellurium concentration in the electrolyte is 250 g / L, free sodium hydroxide concentration is 100 g / L, both the anode and cathode are made of stainless steel plates, and the current density is 70 A / m. 2 With a cell voltage of 1.8V, an electrolysis temperature of 45℃, and an electrolysis cycle of 56 hours, tellurium with a purity of 97.0% was obtained at the cathode.

[0046] Example 3 A method for capturing gold from lead anode mud using antimony-enhanced bismuth comprises the following steps: The reducing coal (coke) and soda ash (sodium carbonate) used in this invention are both sourced from Guangdong Xilong Scientific Co., Ltd.

[0047] (1) A mixed raw material was obtained by mixing lead anode mud, crude bismuth and crude antimony in a mass ratio of 10:2:2. The components and mass percentages of the lead anode mud were Pb 28.44%, Bi 19.79%, Ag 12.31%, Cu 1.56%, Sb 31.81%, As 4.85%, Au 0.45% and Te 0.79%, the components and mass percentages of the crude bismuth were Bi 87.63%, Pb 11.9% and Ag 0.47%, and the components and mass percentages of the crude antimony were Sb 93.85%, As 4.21% and Pb 1%. 94%; after mixing, it is loaded into a reduction furnace for reduction smelting. At the same time, 8% coke and 9% sodium carbonate by mass of the mixed raw materials are added to the smelting furnace. The temperature is controlled at 1250℃ and smelting is carried out for 5 hours to obtain precious lead and antimony-containing flue dust. The components contained in the precious lead by mass percentage are Pb 24.41%, Bi 27.18%, Ag 9.04%, Cu 1.13%, Sb 33.23%, As 3.77%, Te 0.62% and Au 0.62%. After the reduction slag is poured out, the remaining precious lead is sent to the oxidation furnace through a ladle, and the antimony-containing flue dust is collected by a bag filter.

[0048] (2) Preliminary oxidation and impurity removal: The obtained precious lead is added to the oxidation furnace and the temperature is controlled at 900℃. When the time is up, a small amount of oxidation slag is produced, and arsenic-antimony alloy, oxidation slag and antimony-containing flue dust are obtained. The oxidation slag is scooped out and the antimony-containing flue dust is collected by a bag filter. The composition of the obtained antimony-containing flue dust is arsenic oxide, antimony oxide and lead oxide.

[0049] (3) Mid-term oxidation and impurity removal: The arsenic-antimony alloy continues in the oxidation furnace, with the temperature controlled at 950℃. The time is until the oxidation slag stops being generated and dry slag begins to be generated. At this time, the arsenic-antimony lead-bismuth alloy, oxidation slag and dry slag are obtained. The oxidation slag and dry slag are then retrieved.

[0050] (4) Later stage of oxidation and impurity removal: The arsenic-antimony-lead-bismuth alloy continues to be in the oxidation furnace, and the temperature is controlled at 1050℃. Sodium carbonate of 3% of the mass of precious lead in step (2) is added, and the reaction time is 7h. Sodium tellurate slag and gold-silver alloy are obtained. The sodium tellurate slag is collected by scooping, and the gold-silver alloy is poured into the ladle. The gold-silver alloy contains 97.3% silver by mass, 2.15% gold by mass, and 0.55% other impurities.

[0051] (5) The gold-silver alloy obtained in step (4) is placed in a continuous vacuum furnace for vacuum melting. The conditions are: vacuum degree controlled at 10 Pa, temperature at 1200 °C, and distillation time at 12 h to obtain crude silver volatiles and crude gold residue. The crude silver volatiles contain 99.43% silver by mass and the crude gold residue contains 91.27% gold by mass.

[0052] (6) Recovery of gold and silver by electrowinning: using crude silver as the anode and a pure silver plate as the cathode, electrolysis is carried out in a silver nitrate electrolyte with a nitric acid concentration of 30 g / L and a current density of 300 A / m. 2 Temperature 55℃, Ag + With a concentration of 65 g / L, a cell voltage of 1.8 V, an electrode spacing of 76 mm, a diaphragm bag between the cathode and anode, and 0.5 g / L gelatin added to the electrolyte as an additive, silver is deposited in powder form at the cathode with a purity of 99.92%. Using crude gold as the anode and pure gold sheets as the cathode, electrolysis is performed in a chloroauric acid electrolyte. Au is then deposited in the electrolyte. 3+ The concentration is 70 g / L, the free HCl concentration is 70 g / L; the current density is 400 A / m. 2 The cell voltage is 2.5V; the electrolysis temperature is 50℃; the electrode spacing is 80mm; under these conditions, gold is densely deposited at the cathode with a purity of 99.91%; after the electrolysis process, high-purity silver and gold are obtained and can be sold directly, with silver and gold recovery rates of 99.12% and 98.01%, respectively.

[0053] (7) The antimony-containing flue dust obtained in steps (1) and (2) is sent to the crude antimony smelting process for crude antimony recovery. The crude antimony smelting conditions are as follows: 5% sodium carbonate and 5% coke containing antimony flue dust are added, the furnace temperature is controlled at 1250℃, and the time is 6h to obtain crude antimony. The mass percentage of antimony in the crude antimony is 97.22%, which can be used for reduction smelting or sold directly.

[0054] (8) The oxide slag obtained in steps (2) and (3) is sent to the crude bismuth smelting process for crude bismuth recovery. The crude bismuth smelting conditions are: 4% sodium carbonate by mass of oxide slag and 10% coke by mass of oxide slag are added, the temperature is 900℃, and the time is 7h to obtain crude bismuth. The mass percentage of bismuth in the crude bismuth is 88.22%, which can be used for synergistic reduction smelting of lead anode mud.

[0055] (9) The sodium tellurate residue obtained in step (4) is sent to the tellurium integrated recycling workshop for tellurium recovery. The tellurium recovery conditions are as follows: First, alkaline leaching is performed in a sodium hydroxide solution with a concentration of 80 g / L at a leaching temperature of 70°C. The liquid-to-solid ratio of sodium tellurate residue to sodium hydroxide solution is 2:1, and the leaching time is 8 hours, allowing tellurium to enter the solution in the form of sodium tellurite (Na₂TeO₃). After leaching, solid-liquid separation is performed. Sodium sulfide (Na₂S) is added to the obtained leachate for purification to precipitate heavy metal impurities such as copper and lead. The mass ratio of sodium sulfide to sodium tellurate residue is 0.05:1, the reaction temperature is 90°C, and the reaction continues until the precipitate is completely formed. After filtration, a pure tellurium-containing solution is obtained. Finally, the tellurium-containing solution is sent to an electrolytic cell for electrowinning. The electrowinning conditions are controlled as follows: tellurium concentration in the electrolyte is 50 g / L, free sodium hydroxide concentration is 120 g / L, both anode and cathode are made of stainless steel plates, and the current density is 40 A / m. 2 With a cell voltage of 2.6V, an electrolysis temperature of 60℃, and an electrolysis cycle of 80 hours, tellurium product with a purity of 98.22% was obtained at the cathode.

[0056] Example 4 A method for capturing gold from lead anode mud using antimony-enhanced bismuth comprises the following steps: The reducing coal (coke) and soda ash (sodium carbonate) used in this invention are both sourced from Guangdong Xilong Scientific Co., Ltd.

[0057] (1) Lead anode mud, crude bismuth and crude antimony are mixed in a mass ratio of 10:4:1 to obtain a mixed raw material. The components and mass percentages of the lead anode mud are Pb 40%, Bi 10%, Ag 5%, Cu 2%, Sb 37.99%, As 4%, Au 0.02% and Te 0.99%, the components and mass percentages of the crude bismuth are Bi 75.3%, Pb 24.6% and Ag 0.1%, and the components and mass percentages of the crude antimony are Sb 98%, As 1% and Pb 1%. After mixing, the mixture is loaded into a reduction furnace. Reduction smelting was carried out, and 3% coke and 5% sodium carbonate by mass of the mixed raw materials were added to the smelting furnace. The temperature was controlled at 1300℃ for 3 hours to obtain precious lead and antimony-containing flue dust. The components contained in the precious lead by mass percentage were Pb 37.93%, Bi 20.22%, Ag 4.21%, Cu 1.5%, Sb 32.55%, As 2.8%, Te 0.76%, and Au 0.03%. After the reduction slag was poured out, the remaining precious lead was sent to the oxidation furnace through a ladle, and the antimony-containing flue dust was collected by a bag filter.

[0058] (2) Preliminary oxidation and impurity removal: The obtained precious lead is added to the oxidation furnace and the temperature is controlled at 800℃. When the time is up, a small amount of oxidation slag is produced, and arsenic-antimony alloy, oxidation slag and antimony-containing flue dust are obtained. The oxidation slag is scooped out and the antimony-containing flue dust is collected by a bag filter. The composition of the obtained antimony-containing flue dust is arsenic oxide, antimony oxide and lead oxide.

[0059] (3) Mid-term oxidation and impurity removal: The arsenic-antimony alloy continues in the oxidation furnace, with the temperature controlled at 900℃. The time is until the oxidation slag stops being generated and dry slag begins to be generated. At this time, the arsenic-antimony lead-bismuth alloy, oxidation slag and dry slag are obtained. The oxidation slag and dry slag are then retrieved.

[0060] (4) Later stage of oxidation and impurity removal: The arsenic-antimony-lead-bismuth alloy continues to be in the oxidation furnace, and the temperature is controlled at 1000℃. Sodium carbonate of 1% of the mass of the precious lead in step (2) is added. The reaction time is 5h to obtain sodium tellurate slag and gold-silver alloy. The sodium tellurate slag is collected by scooping. The gold-silver alloy is poured into the ladle. The gold-silver alloy contains 97.77% silver by mass, 1.25% gold by mass, and 0.98% other impurities.

[0061] (5) The gold-silver alloy obtained in step (4) is placed in a continuous vacuum furnace for vacuum melting. The conditions are: vacuum degree of 5 Pa, temperature of 1000℃, and distillation time of 8 h to obtain crude silver volatiles and crude gold residue. The crude silver volatiles contain 99.22% silver by mass and the crude gold residue contains 92.33% gold by mass.

[0062] (6) Recovery of gold and silver by electrowinning: using crude silver as the anode and a pure silver plate as the cathode, electrolysis is carried out in a silver nitrate electrolyte with a nitric acid concentration of 20 g / L and a current density of 200 A / m. 2 Temperature 45℃, Ag + With a concentration of 55 g / L, a cell voltage of 2.2 V, an electrode spacing of 86 mm, and a diaphragm bag between the cathode and anode, and with 1.5 g / L gelatin added to the electrolyte as an additive, silver precipitates as powder at the cathode under these conditions, with a purity of 98.97%. Using crude gold as the anode and pure gold sheets as the cathode, electrolysis is performed in a chloroauric acid electrolyte. Au in the electrolyte... 3+ With a concentration of 50 g / L and a free HCl concentration of 90 g / L; a current density of 300 A / m²; a cell voltage of 1 V; an electrolysis temperature of 60 °C; and an electrode spacing of 70 mm, gold was densely deposited at the cathode with a purity of 98.67%. After electrolysis, high-purity silver and gold were obtained and could be sold directly, with silver and gold recovery rates of 98.11% and 97.12%, respectively.

[0063] (7) The antimony-containing flue dust obtained in steps (1) and (2) is sent to the crude antimony smelting process for crude antimony recovery. The crude antimony smelting conditions are as follows: sodium carbonate containing 2% by mass of antimony flue dust and coke containing 2% by mass of antimony flue dust are added, the furnace temperature is controlled at 1200℃, and the time is 8h to obtain crude antimony. The mass percentage of antimony in the crude antimony is 90.1%, which can be used for reduction smelting or sold directly.

[0064] (8) The oxide slag obtained in steps (2) and (3) is sent to the crude bismuth smelting process for crude bismuth recovery. The crude bismuth smelting conditions are: 1% sodium carbonate by mass of oxide slag and 5% coke by mass of oxide slag are added, the temperature is 750℃, and the time is 5h to obtain crude bismuth. The mass percentage of bismuth in the crude bismuth is 78.44%, which can be used for synergistic reduction smelting of lead anode mud.

[0065] (9) The sodium tellurate residue obtained in step (4) is sent to the tellurium comprehensive recycling workshop for tellurium recovery. The tellurium recovery conditions are as follows: first, alkaline leaching is carried out in a sodium hydroxide solution with a concentration of 40 g / L, the leaching temperature is 60℃, the liquid-solid ratio of sodium tellurate residue to sodium hydroxide solution is 2:1, and the leaching time is 8h, so that tellurium enters the solution in the form of sodium tellurite (Na2TeO3); after leaching, solid-liquid separation is carried out, and sodium sulfide (N2TeO3) is added to the obtained leachate. Sodium sulfide (Sodium sulfide) is used for purification to precipitate heavy metal impurities such as copper and lead. The mass ratio of sodium sulfide to sodium tellurate slag is 0.01:1, the reaction temperature is 60℃, and the reaction continues until the precipitate is completely formed. After filtration, a pure tellurium-containing solution is obtained. Finally, the tellurium-containing solution is sent to an electrolytic cell for electrowinning. The electrowinning conditions are controlled as follows: tellurium concentration in the electrolyte is 40 g / L, free sodium hydroxide concentration is 60 g / L, both the anode and cathode are made of stainless steel plates, and the current density is 30 A / m. 2 With a cell voltage of 1.4V, an electrolysis temperature of 50℃, and an electrolysis cycle of 36 hours, tellurium product with a purity of 95.2% was obtained at the cathode.

[0066] Example 5 A method for capturing gold from lead anode mud using antimony-enhanced bismuth comprises the following steps: The reducing coal (coke) and soda ash (sodium carbonate) used in this invention are both sourced from Guangdong Xilong Scientific Co., Ltd.

[0067] (1) Lead anode mud, crude bismuth, and crude antimony were mixed in a mass ratio of 20:6:3 to obtain a mixed raw material. The components and mass percentages of the lead anode mud were Pb 39.61%, Bi 16%, Ag 15%, Cu 1.1%, Sb 22%, As 5%, Au 0.3%, and Te 0.99%. The components and mass percentages of the crude bismuth were Bi 89.33%, Pb 10.2%, and Ag 0.47%. The components and mass percentages of the crude antimony were Sb 90.5%, As 8%, and Pb 1.5%. After mixing, the mixture was loaded into a reducing agent. Reduction smelting was carried out in a furnace, while 7% coke and 10% sodium carbonate by mass of the mixed raw materials were added to the furnace. The temperature was controlled at 1200℃ for 8 hours to obtain precious lead and antimony-containing flue dust. The components contained in the precious lead by mass percentage were Pb 29.62%, Bi 30.03%, Ag 11.03%, Cu 0.98%, Sb 24.22%, As 3.22%, Te 0.65%, and Au 0.25%. After the reduction slag was poured out, the remaining precious lead was sent to the oxidation furnace through a ladle, and the antimony-containing flue dust was collected by a bag filter.

[0068] (2) Preliminary oxidation and impurity removal: The obtained precious lead is added to the oxidation furnace and the temperature is controlled at 900℃. When the time is up, a small amount of oxidation slag is produced, and arsenic-antimony alloy, oxidation slag and antimony-containing flue dust are obtained. The oxidation slag is scooped out and the antimony-containing flue dust is collected by a bag filter. The composition of the obtained antimony-containing flue dust is arsenic oxide, antimony oxide and lead oxide.

[0069] (3) Mid-term oxidation and impurity removal: The arsenic-antimony alloy continues in the oxidation furnace, with the temperature controlled at 1000℃. The time is until the oxidation slag stops being generated and dry slag begins to be generated. At this time, the arsenic-antimony lead-bismuth alloy, oxidation slag and dry slag are obtained. The oxidation slag and dry slag are then retrieved.

[0070] (4) Later stage of oxidation and impurity removal: The arsenic-antimony-lead-bismuth alloy continues to be in the oxidation furnace, and the temperature is controlled at 1100℃. Sodium carbonate of 3% of the mass of precious lead in step (2) is added, and the reaction time is 3h. Sodium tellurate slag and gold-silver alloy are obtained. The sodium tellurate slag is collected by scooping, and the gold-silver alloy is poured into the ladle. The gold-silver alloy contains 97.42% silver by mass, 2.07% gold by mass, and 0.51% other impurities.

[0071] (5) The gold-silver alloy obtained in step (4) is placed in a continuous vacuum furnace for vacuum melting. The conditions are: vacuum degree controlled at 17 Pa, temperature at 1100 °C, and distillation time at 15 h to obtain crude silver volatiles and crude gold residue. The crude silver volatiles contain 98.21% silver by mass and the crude gold residue contains 90.11% gold by mass.

[0072] (6) Recovery of gold and silver by electrowinning: using crude silver as the anode and a pure silver plate as the cathode, electrolysis is carried out in a silver nitrate electrolyte with a nitric acid concentration of 30 g / L and a current density of 300 A / m. 2 Temperature 55℃, Ag + With a concentration of 65 g / L, a cell voltage of 1.8 V, an electrode spacing of 76 mm, and a diaphragm bag between the cathode and anode, and with 1 g / L gelatin added to the electrolyte as an additive, silver precipitates as powder at the cathode with a purity of 99.01%, while gold is enriched in the anode slime. Using crude gold as the anode and pure gold sheets as the cathode, electrolysis is performed in a chloroauric acid electrolyte. Au is then added to the electrolyte. 3+ The concentration of gold was 70 g / L, the free HCl concentration was 70 g / L, the current density was 400 A / m², the cell voltage was 2.5 V, the electrolysis temperature was 50 °C, and the electrode spacing was 80 mm. Under these conditions, gold was densely deposited at the cathode with a purity of 98.71%. After electrolysis, high-purity silver and gold were obtained and could be sold directly. The recovery rates of silver and gold were 98.12% and 97.21%, respectively.

[0073] (7) The antimony-containing flue dust obtained in steps (1) and (2) is sent to the crude antimony smelting process for crude antimony recovery. The crude antimony smelting conditions are as follows: sodium carbonate containing 3% of the mass of antimony flue dust and coke containing 3% of the mass of antimony flue dust are added, the furnace temperature is controlled at 1300℃, and the time is 3h to obtain crude antimony. The mass percentage of antimony in the crude antimony is 97.22%, which can be used for reduction smelting or sold directly.

[0074] (8) The oxide slag obtained in steps (2) and (3) is sent to the crude bismuth smelting process for crude bismuth recovery. The crude bismuth smelting conditions are: 5% sodium carbonate by mass of oxide slag and 15% coke by mass of oxide slag are added, the temperature is 1000℃, and the time is 2h to obtain crude bismuth. The mass percentage of bismuth in the crude bismuth is 86.39%, which can be used for synergistic reduction smelting of lead anode mud.

[0075] (9) The sodium tellurate residue obtained in step (4) is sent to the tellurium comprehensive recycling workshop for tellurium recovery. The tellurium recovery conditions are as follows: first, alkaline leaching is carried out in a sodium hydroxide solution with a concentration of 40 g / L, the leaching temperature is 60℃, the liquid-solid ratio of sodium tellurate residue to sodium hydroxide solution is 2:1, the leaching time is 8h, so that tellurium enters the solution in the form of sodium tellurite (Na2TeO3); after leaching, solid-liquid separation is carried out, and sodium sulfide (Na2S) is added to the obtained leaching solution for purification, which is used to precipitate heavy metal impurities such as copper and lead. The ratio of sodium sulfide to sodium tellurate residue is 0.01:1, the reaction temperature is 60℃, and a pure tellurium-containing solution is obtained after filtration; finally, the tellurium-containing solution is sent to an electrolytic cell for electrowinning. The electrowinning conditions are controlled as follows: tellurium concentration in the electrolyte is 40 g / L, free sodium hydroxide concentration is 60 g / L, stainless steel plates are used for both the anode and cathode, and the current density is 30 A / m 2With a cell voltage of 1.4V, an electrolysis temperature of 50℃, and an electrolysis cycle of 70 hours, tellurium product with a purity of 97.56% was obtained at the cathode.

[0076] Comparative Example 1 The difference between this embodiment and Embodiment 2 is that only lead anode mud and crude bismuth are added during reduction smelting, and the mass ratio is 10:2. The recovery rates of silver and gold obtained are 95.18% and 92.25%, respectively. Compared with Embodiment 1, the recovery rates of silver and gold decreased by 3.45% and 4.97%, respectively.

[0077] This indicates that adding crude antimony can effectively enrich gold and silver into the precious lead product of reduction smelting, reducing the loss of gold and silver during the reduction smelting process; at the same time, the enrichment of bismuth with gold reduces the intangible losses caused by volatilization during the oxidation stage.

[0078] Comparative Example 2 The difference between this embodiment and Embodiment 3 is that only lead anode mud and crude bismuth are added during reduction smelting, and the mass ratio is 10:2. The recovery rates of silver and gold obtained are 95.72% and 90.21%, respectively. Compared with Embodiment 3, the recovery rates of silver and gold decreased by 3.4% and 7.8%, respectively, indicating that antimony enhances the gold capture effect of bismuth, thereby reducing the loss of gold during the impurity removal process.

[0079] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for capturing gold from lead anode mud using antimony-enhanced bismuth, characterized in that: Includes the following steps: (1) After mixing lead anode mud, crude bismuth and crude antimony, reducer coal and soda ash are added for reduction smelting to obtain precious lead, reducing slag and antimony-containing flue ash; (2) Precious lead is subjected to oxidation and impurity removal process to obtain arsenic-antimony alloy, oxide slag and antimony-containing flue dust; (3) The arsenic-antimony alloy was subjected to an oxidation and impurity removal process to obtain an arsenic-antimony-lead-bismuth alloy, oxidation slag and dry slag; (4) Add soda ash to the arsenic-antimony-lead-bismuth alloy, and obtain sodium tellurate slag and gold-silver alloy after oxidation and impurity removal. (5) The gold-silver alloy is smelted in a vacuum to obtain crude silver and crude gold; (6) Silver and gold are recovered by electrowinning; (7) Add the antimony-containing flue ash obtained in steps (1) and (2) to reducing coal and soda ash to recover crude antimony; (8) Add the oxidized residue obtained in steps (2) and (3) to reducing coal and soda ash for crude bismuth recovery; (9) The sodium tellurate residue obtained in step (4) is subjected to alkaline leaching, solid-liquid separation, sulfide precipitation and electrowinning to recover tellurium.

2. The method for capturing gold in lead anode mud with antimony-enhanced bismuth according to claim 1, characterized in that: In step (1), the lead anode mud comprises the following components by mass percentage: Pb 25%~40%, Bi 10%~20%, Ag 5%~15%, Cu 1%~2%, Sb 20%~40%, As 3~5%, Au 0.02%~0.5% and Te <1%, with the total mass percentage of the components being 100%; the crude bismuth comprises the following components by mass percentage: Bi 75%~89.9%, Pb 10%~25% and Ag 0.1%~0.5%, with the total mass percentage of the components being 100%; the crude antimony comprises the following components by mass percentage: Sb 90%~98%, As 1%~8% and Pb 1%~2%; wherein the mass ratio of lead anode mud, crude bismuth and crude antimony is 10:(2-4):(1-2); and the reduction smelting conditions are: temperature 1200~1300℃, time 3~8h, addition of reducing coal of 3~8% of the raw material mass, and soda ash of 5~10% of the raw material mass.

3. The method for capturing gold in lead anode mud with antimony-enhanced bismuth according to claim 1, characterized in that: The conditions for the initial stage of oxidation and impurity removal in step (2) are: temperature 800~900℃, and time until oxidation slag is produced.

4. The method for capturing gold in lead anode mud with antimony-enhanced bismuth according to claim 1, characterized in that: The conditions for the intermediate stage of oxidation and impurity removal in step (3) are: temperature 900~1000℃, time until oxidation slag stops being generated and dry slag is generated.

5. The method for capturing gold in lead anode mud with antimony-enhanced bismuth according to claim 1, characterized in that: The conditions for the later stage of oxidation and impurity removal in step (4) are: temperature 1000~1100℃, time 3~8h, and the amount of soda ash added is 1~3% of the mass of precious lead in step (2).

6. The method for capturing gold in lead anode mud with antimony-enhanced bismuth according to claim 1, characterized in that: The conditions for vacuum melting in step (5) are: vacuum degree 5~20Pa, temperature 1000~1200℃, and melting time 8~15h.

7. The method for capturing gold in lead anode mud with antimony-enhanced bismuth according to claim 1, characterized in that: The conditions for recovering silver by electrowinning in step (6) are: using crude silver as the anode, adding gelatin to an electrolyte containing silver nitrate to recover silver; the conditions for recovering gold by electrowinning are: using crude gold as the anode, recovering gold in an electrolyte containing chloroauric acid.

8. The method for capturing gold in lead anode mud with antimony-enhanced bismuth according to claim 1, characterized in that: The conditions for crude antimony recovery in step (7) are as follows: the amount of reducing coal added is 2-6% of the mass of antimony-containing flue ash, the amount of soda ash added is 2-5% of the mass of antimony-containing flue ash, the temperature is 1200-1300℃, and the time is 3-8h.

9. The method for capturing gold in lead anode mud with antimony-enhanced bismuth according to claim 1, characterized in that: The conditions for crude bismuth recovery in step (8) are as follows: the amount of reducing coal added is 5-15% of the mass of the oxidized slag, the amount of soda ash added is 1-5% of the mass of the oxidized slag, the temperature is 750-1000℃, and the time is 2-7h.

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