阅读说明：本技术 一种铜阳极泥中有价金属的回收方法 (Method for recovering valuable metals in copper anode slime ) 是由 杨斌 徐宝强 邓聚海 蒋文龙 刘大春 田阳 李一夫 孔令鑫 杨佳 于 2021-10-13 设计创作，主要内容包括：本发明提供了一种铜阳极泥中有价金属的回收方法,属于铜阳极泥综合处理技术领域。本发明的回收方法高效回收了铜阳极泥中的硒、铜、碲、砷、铅、铋及贵金属金银,采用两步真空碳热还原法替代了传统火法中阳极泥还原熔炼和贵铅分步吹炼,避免了传统工艺含砷烟尘的排放；本发明回收得到的富金残留物几乎不含贱金属铅铋锑砷等,经氯化分金和还原后可得金粉,较传统工艺贱金属含量更低,大大降低了产出渣量和生产周期,减少了贵金属在渣中的损失。本发明的整个回收方法缩短了贵金属的回收周期,提高了有价金属的直收率,且真空碳热还原过程为密闭系统,整个流程避免了烟尘的排放,改善工作环境的同时解决了砷的回收排放问题,且过程简单、环境友好。(The invention provides a method for recovering valuable metals in copper anode slime, and belongs to the technical field of comprehensive treatment of copper anode slime. The recovery method of the invention efficiently recovers selenium, copper, tellurium, arsenic, lead, bismuth and noble metals gold and silver in the copper anode slime, adopts a two-step vacuum carbothermic reduction method to replace anode slime reduction smelting and noble lead step-by-step converting in the traditional pyrogenic process, and avoids the emission of arsenic-containing smoke dust in the traditional process; the gold-rich residue obtained by recovery of the invention hardly contains base metals such as lead, bismuth, antimony and arsenic, and the gold powder can be obtained after chlorination gold separation and reduction, and compared with the traditional process, the content of the base metals is lower, the produced slag quantity and the production period are greatly reduced, and the loss of noble metals in slag is reduced. The whole recovery method shortens the recovery period of the precious metal, improves the direct recovery rate of the valuable metal, adopts a closed system in the vacuum carbothermic reduction process, avoids the emission of smoke dust in the whole process, improves the working environment, solves the problem of arsenic recovery and emission, and has simple process and environmental protection.)

1. A method for recovering valuable metals in copper anode slime is characterized by comprising the following steps:

mixing copper anode mud and concentrated sulfuric acid, and carrying out sulfating roasting to obtain selenium-containing smoke dust and roasted sand;

sequentially carrying out water absorption, first reduction and drying on the selenium-containing smoke dust to obtain crude selenium;

mixing the calcine with a sulfuric acid solution, and carrying out oxygen pressure acid leaching to obtain a leaching solution containing copper and tellurium and anode mud subjected to copper, selenium and tellurium removal;

mixing the leaching solution containing copper and tellurium with copper powder, and carrying out secondary reduction to obtain copper and tellurium slag and a copper sulfate solution;

mixing the anode mud subjected to copper removal, selenium removal and tellurium removal with first charcoal, and performing low-temperature vacuum carbothermic reduction to obtain an arsenic oxide volatile matter and arsenic removal anode mud; the temperature of the low-temperature vacuum carbothermic reduction is 400-550 ℃;

carrying out high-temperature vacuum carbothermic reduction on the dearsenified anode mud to obtain lead-bismuth mixed volatile matters and gold, silver and antimony-rich residues; the temperature of the high-temperature vacuum carbothermic reduction is 850-1100 ℃;

carrying out vacuum distillation on the gold-silver-antimony-rich residues to obtain silver-antimony volatile matters and gold-rich residues;

oxidizing and refining the silver-antimony volatile matter to obtain antimony oxide volatile matter and crude silver, and electrolyzing the crude silver to obtain electrolytic silver;

and (4) carrying out chlorination gold separation, third reduction and electrolysis on the gold-rich residue in sequence to obtain the electrogold.

2. The recovery method according to claim 1, wherein the mass ratio of the copper anode slime to concentrated sulfuric acid is 1 (0.7-1.2), the mass concentration of the concentrated sulfuric acid is 98%, the temperature of the sulfating roasting is 250-650 ℃, and the time is 1-4 h.

3. The recovery method according to claim 1, wherein the crude selenium has a purity of 85 to 99%.

4. The recovery method according to claim 1, wherein in the step of the acid leaching by oxygen pressure, the acidity of the sulfuric acid solution is 100 to 140 g/L; the dosage ratio of the sulfuric acid solution to the calcine is (5-8) L:1kg, the temperature of the oxygen pressure acid leaching is 100-150 ℃, the leaching time is 0.5-4 h, and the leaching pressure is 0.8-1.2 Mpa.

5. The recovery method according to claim 1, wherein the decoppering rate of the oxygen pressure acid leaching step is not less than 98%.

6. The recycling method according to claim 1, wherein in the low-temperature vacuum carbothermic reduction step, the mass of the first charcoal is 20-35% of the mass of the anode mud of the decoppered selenium and tellurium, and the system pressure of the low-temperature vacuum carbothermic reduction is 1-50 Pa, and the time is 2-6 h.

7. The recycling method according to claim 1, further comprising mixing the dearsenified anode mud with a second charcoal, wherein the mass of the second charcoal is 0-10% of the mass of the dearsenified anode mud, and the system pressure of the high-temperature vacuum carbothermic reduction is 1-50 Pa for 2-6 h before the high-temperature vacuum carbothermic reduction.

8. The recovery method according to claim 1, wherein the temperature of the vacuum distillation is 1300 to 1500 ℃, the system pressure is 1 to 50Pa, and the time is 6 to 8 hours.

9. The recovery method according to claim 1, wherein the temperature of the oxidative refining is 950 to 1100 ℃ and the time is 3 to 10 hours.

10. The recovery method according to claim 1, wherein the processes of gold chloride separation, third reduction and electrolysis comprise: and (3) carrying out chlorination gold separation on the gold-rich residues, introducing sulfur dioxide into the obtained gold liquid, reducing, and electrolyzing the obtained gold powder to obtain the electrogold.

Technical Field

The invention relates to the technical field of comprehensive treatment of copper anode slime, in particular to a method for recovering valuable metals in copper anode slime.

Background

The copper anode mud is a gray black mud which is insoluble and attached to the surface of a residual anode or precipitated at the bottom of an electrolytic tank and contains impurity metals with higher reduction potential, such as bismuth, silver, antimony, copper and the like, during the electrolytic refining of the crude copper, has the particle size of about 200 meshes, and generally has the mass of about 0.2-1.0% of that of an anode plate. Barium sulfate is introduced into anode mud as a cathode plate release agent, and most of barium sulfate is enriched into copper anode mud in the copper electrolysis process. The copper anode slime contains a large amount of gold, silver, copper, lead, bismuth, selenium, tellurium and platinum group noble metals, and is one of main raw materials for extracting rare noble metals.

The key points for extracting the noble metals and the rare metals are the removal of base metals such as lead and bismuth and the enrichment of the noble metals. At present, a plurality of methods for treating anode mud are available, and the widely applied processes include the traditional pyrometallurgical process, the Kaldo furnace process, the combined dressing and metallurgy process, the full-wet process, the semi-wet process and the like, which are generally divided into the pyrometallurgical process and the wet process. In the traditional pyrometallurgical process, the base metals such as lead, bismuth and the like are removed mainly in the oxidation refining process of a silver separating furnace, and the base metals are oxidized step by step into slag or smoke dust and separated from precious metals by mainly utilizing the difference of the affinity of each metal element and oxygen. But the process has more working procedures, long treatment time and more slag and smoke dust.

The wet process mainly adopts a chlorination method for gold leaching, lead is dissolved into a liquid phase, sulfuric acid is added to lead to generate lead sulfate precipitate to inhibit lead dissolution, but lead can be dissolved to a certain extent under the influence of chloride ion concentration and solution acidity, bismuth in the precious metal enrichment slag can be partially dissolved under the generally adopted gold separation condition, but bismuth is easy to hydrolyze, so that the content of bismuth in the solution is lower as long as the proper pH value of the solution is controlled. After anode mud of a Guixi smelting plant is subjected to sulfating roasting, copper leaching by sulfuric acid and tellurium separation by sodium hydroxide, adding sodium sulfide into tellurium separation liquid to precipitate lead; the tellurium-separated slag is subjected to potassium chlorate gold separation and sulfur dioxide reduction to obtain bismuth-containing reducing solution, and the conventional method is to replace valuable metals with zinc, but the phenomena that the precious metals are not completely reduced (containing 1mg/L of gold) and the bismuth metal is not recovered exist. The pH value is adjusted to precipitate bismuth in the form of bismuth oxychloride, the liquid after reaction is replaced by zinc powder, rare and precious metals such as gold, platinum, palladium and the like enter platinum-palladium concentrate in a metallic form, and the precipitated bismuth oxychloride is washed and filtered to be used as a raw material for refining bismuth. The problems of complicated working procedures, more auxiliary materials, three wastes and the like generally exist in the wet process flow, and the improved vacuum treatment flow improves the traditional silver separating furnace process, but does not solve the problems of long reduction smelting section period, large smoke dust amount and the like of the noble lead furnace.

The selection and metallurgy combined flow process mainly comprises the following parts: (1) pretreating copper anode mud; (2) flotation; (3) smelting; (4) and (4) flotation tailing treatment. The combined process can effectively improve the process efficiency, but the treatment process is complex and low in efficiency, and particularly the flotation tailings have large silver-gold dispersion and high valuable metal content and are difficult to further treat.

Disclosure of Invention

The invention aims to provide a method for recovering valuable metals from copper anode slime, which can efficiently recover selenium, copper, tellurium, arsenic, lead, bismuth and noble metals of gold and silver from the copper anode slime.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a method for recovering valuable metals in copper anode slime, which comprises the following steps:

mixing copper anode mud and concentrated sulfuric acid, and carrying out sulfating roasting to obtain selenium-containing smoke dust and roasted sand;

sequentially carrying out water absorption, first reduction and drying on the selenium-containing smoke dust to obtain crude selenium;

mixing the calcine with a sulfuric acid solution, and carrying out oxygen pressure acid leaching to obtain a leaching solution containing copper and tellurium and anode mud subjected to copper, selenium and tellurium removal;

mixing the leaching solution containing copper and tellurium with copper powder, and carrying out secondary reduction to obtain copper and tellurium slag and a copper sulfate solution;

mixing the anode mud subjected to copper removal, selenium removal and tellurium removal with first charcoal, and performing low-temperature vacuum carbothermic reduction to obtain an arsenic oxide volatile matter and arsenic removal anode mud; the temperature of the low-temperature vacuum carbothermic reduction is 400-550 ℃;

carrying out high-temperature vacuum carbothermic reduction on the dearsenified anode mud to obtain lead-bismuth mixed volatile matters and gold, silver and antimony-rich residues; the temperature of the high-temperature vacuum carbothermic reduction is 850-1100 ℃;

carrying out vacuum distillation on the gold-silver-antimony-rich residues to obtain silver-antimony volatile matters and gold-rich residues;

oxidizing and refining the silver-antimony volatile matter to obtain antimony oxide volatile matter and crude silver, and electrolyzing the crude silver to obtain electrolytic silver;

and (4) carrying out chlorination gold separation, third reduction and electrolysis on the gold-rich residue in sequence to obtain the electrogold.

Preferably, the mass ratio of the copper anode slime to concentrated sulfuric acid is 1 (0.7-1.2), the mass concentration of the concentrated sulfuric acid is 98%, the sulfating roasting temperature is 250-650 ℃, and the time is 1-4 hours.

Preferably, the purity of the crude selenium is 85-99%.

Preferably, in the step of acid leaching by oxygen pressure, the acidity of the sulfuric acid solution is 100-140 g/L; the dosage ratio of the sulfuric acid solution to the calcine is (5-8) L:1kg, the temperature of the oxygen pressure acid leaching is 100-150 ℃, the leaching time is 0.5-4 h, and the leaching pressure is 0.8-1.2 Mpa.

Preferably, the decoppering rate of the oxygen pressure acid leaching step is more than or equal to 98 percent.

Preferably, in the low-temperature vacuum carbothermic reduction step, the mass of the first charcoal is 20-35% of that of the anode mud for removing copper, selenium and tellurium, the system pressure of the low-temperature vacuum carbothermic reduction is 1-50 Pa, and the time is 2-6 h.

Preferably, before the high-temperature vacuum carbothermic treatment, the dearsenifying anode mud is mixed with second charcoal, the mass of the second charcoal is 0-10% of that of the dearsenifying anode mud, the system pressure of the high-temperature vacuum carbothermic reduction is 1-50 Pa, and the time is 2-6 h.

Preferably, the temperature of the vacuum distillation is 1300-1500 ℃, the system pressure is 1-50 Pa, and the time is 6-8 h.

Preferably, the temperature of the oxidation refining is 950-1100 ℃, and the time is 3-10 h.

Preferably, the gold chloride separation, the third reduction and the electrolysis process comprise: and (3) carrying out chlorination gold separation on the gold-rich residues, introducing sulfur dioxide into the obtained gold liquid, reducing, and electrolyzing the obtained gold powder to obtain the electrogold.

The invention provides a method for recovering valuable metals in copper anode slime, which comprises the steps of firstly, sulfating roasting and selenium steaming the copper anode slime, absorbing the obtained selenium-containing flue gas by water to obtain crude selenium, leaching the roasted product obtained by sulfating roasting by using oxygen pressure acid to remove copper, selenium and tellurium, replacing the obtained leachate by copper powder to obtain copper telluride slag for recovering tellurium, and recovering copper from the replaced solution in the form of copper sulfate; adding charcoal into the anode slime subjected to oxygen pressure acid leaching to perform stepwise carbothermic reduction, performing low-temperature vacuum carbothermic reduction in the first step to convert arsenic into volatile arsenic oxide, performing dearsenization in the form of arsenic oxide, performing high-temperature vacuum carbothermic reduction in the second step, volatilizing lead, bismuth and partial silver into volatile matters in the form of compounds or simple substances, and enriching gold, silver, antimony, barium and the like in residues; and (3) distilling the residue in vacuum to volatilize silver and antimony, then carrying out oxidation refining to obtain crude silver, carrying out electrolytic refining on the crude silver to obtain electrolytic silver, enriching gold in the copper anode mud in the residue obtained by distillation, and carrying out chlorination gold separation, reduction and electrolysis to obtain the electrolytic gold.

The recovery method of the invention efficiently recovers selenium, copper, tellurium, arsenic, lead, bismuth and noble metals gold and silver in the copper anode slime, adopts a two-step vacuum carbothermic reduction method to replace anode slime reduction smelting and noble lead step-by-step converting in the traditional pyrogenic process, and avoids the emission of arsenic-containing smoke dust in the traditional process; the step-by-step blowing of the precious lead is to separate the valuable metals (Pb, Bi, Sb, As and the like) except the precious metals from the precious metals in the form of slag and smoke by utilizing the difference of affinity of the valuable metals and oxygen, and the recovery time is long (the step-by-step blowing of the precious lead is 61-77 h/furnace, and the precious lead is treated in a single furnace for 3 t).

The copper-tellurium slag recovered by the method can be used for recovering tellurium, arsenic oxide volatile matters produced by the low-temperature vacuum carbothermic reduction section can be further purified in vacuum to obtain high-purity arsenic oxide, the volatile matters produced by the high-temperature vacuum carbothermic reduction section contain a large amount of lead bismuth and part of silver, the volatile matters are returned to a lead bottom blowing smelting system, the lead bismuth is reduced into crude metal, the silver is supplemented by the lead and then enters the crude metal, the removal efficiency of the lead bismuth is ensured, and the loss of the silver is avoided.

The raw materials for oxidation refining of the invention only contain Ag-Sb and a small amount of impurities (no Pb, Bi and As), so that the traditional refining time is greatly shortened (4-6 days/10 tons of noble lead are needed in the traditional oxidation refining process of the noble lead, and the two-stage vacuum carbothermic reduction time of the invention is 4-12 h in total).

The gold-rich residue obtained by recovery of the invention hardly contains base metals such as lead, bismuth, antimony and arsenic, and the gold powder can be obtained after chlorination gold separation and reduction, and compared with the traditional process, the content of the base metals is lower, the produced slag quantity is greatly reduced, and the loss of noble metals in slag is reduced.

The whole recovery method shortens the recovery period of the precious metals, improves the direct recovery rate of the valuable metals, adopts a closed system in the vacuum carbothermic reduction process, avoids the emission of smoke dust in the whole process, improves the working environment, solves the problem of arsenic recovery and emission, and has simple process and environmental protection.

Drawings

FIG. 1 is a flow chart of a method for recovering valuable metals from copper anode slime according to the invention;

FIG. 2 is an XRD pattern of the arsenic oxide volatiles obtained after the low temperature carbothermic reduction of example 1;

FIG. 3 is an XRD pattern of the residue obtained after the low temperature carbothermic reduction of example 1;

FIG. 4 is an XRD pattern of the lead bismuth mixed volatiles obtained after high temperature carbothermic reduction in example 1;

FIG. 5 is an XRD pattern of the gold, silver and antimony-rich residue obtained after high temperature carbothermic reduction in example 1;

FIG. 6 is an XRD pattern of arsenic oxide volatiles and residues obtained after low temperature carbothermic reduction of example 2;

FIG. 7 is the XRD patterns of the mixed volatiles of lead and bismuth and the residue rich in gold, silver and antimony obtained after the high-temperature carbothermic reduction in example 2.

Detailed Description

The invention provides a method for recovering valuable metals in copper anode slime, which comprises the following steps:

mixing copper anode mud and concentrated sulfuric acid, and carrying out sulfating roasting to obtain selenium-containing smoke dust and roasted sand;

sequentially carrying out water absorption, first reduction and drying on the selenium-containing smoke dust to obtain crude selenium;

mixing the calcine with a sulfuric acid solution, and carrying out oxygen pressure acid leaching to obtain a leaching solution containing copper and tellurium and anode mud subjected to copper, selenium and tellurium removal;

mixing the leaching solution containing copper and tellurium with copper powder, and carrying out secondary reduction to obtain copper and tellurium slag and a copper sulfate solution;

mixing the anode mud subjected to copper removal, selenium removal and tellurium removal with first charcoal, and performing low-temperature vacuum carbothermic reduction to obtain an arsenic oxide volatile matter and arsenic removal anode mud; the temperature of the low-temperature vacuum carbothermic reduction is 400-550 ℃;

carrying out high-temperature vacuum carbothermic reduction on the dearsenified anode mud to obtain lead-bismuth mixed volatile matters and gold, silver and antimony-rich residues; the temperature of the high-temperature vacuum carbothermic reduction is 850-1100 ℃;

carrying out vacuum distillation on the gold-silver-antimony-rich residues to obtain silver-antimony volatile matters and gold-rich residues;

oxidizing and refining the silver-antimony volatile matter to obtain antimony oxide volatile matter and crude silver, and electrolyzing the crude silver to obtain electrolytic silver;

and (4) carrying out chlorination gold separation, third reduction and electrolysis on the gold-rich residue in sequence to obtain the electrogold.

In the present invention, the starting materials or reagents required are commercially available products well known to those skilled in the art unless otherwise specified.

The invention mixes the copper anode mud and concentrated sulfuric acid, and carries out sulfating roasting to obtain selenium-containing smoke dust and roasted sand. The source and the composition of the copper anode slime are not specially limited, and the copper anode slime with corresponding components can be obtained according to the sources well known in the field. In an embodiment of the invention, the composition of the copper anode slime comprises Pb 6.18%, Sb 4.2%, As 5.82%, Bi 7.28%, Cu 14.18%, Ag 10.65%, Se 4.03%, Te 1.02%, Ni 6.16%, and Au 529.6 g/t.

In the invention, the mass ratio of the copper anode mud to the concentrated sulfuric acid is preferably 1 (0.7-1.2), more preferably 1:1, and the mass concentration of the concentrated sulfuric acid is preferably 98%.

Before the copper anode slime is mixed with concentrated sulfuric acid, the method preferably adopts a conventional method to screen and remove large-particle inclusions in the copper anode slime. The process of mixing the copper anode slime and the concentrated sulfuric acid is not particularly limited in the invention, and the copper anode slime and the concentrated sulfuric acid can be mixed according to the process well known in the art, and in the embodiment of the invention, the copper anode slime and the concentrated sulfuric acid are mixed in a stirring tank.

In the invention, the temperature of the sulfating roasting is preferably 250-650 ℃, more preferably 500 ℃, and the time is preferably 1-4 h; the sulfating roasting is preferably carried out in a rotary kiln, the kiln head temperature of the rotary kiln is preferably 250-300 ℃, the temperature in the kiln is preferably 500-600 ℃, and the kiln tail temperature is preferably 550-650 ℃.

In the present invention, the selenium in the selenium-containing smoke is preferably in the form of SeO₂。

After the selenium-containing smoke dust is obtained, the invention sequentially carries out water absorption, first reduction and drying on the selenium-containing smoke dust to obtain crude selenium. The process of the water absorption in the present invention is not particularly limited, and may be carried out according to a process well known in the art. In the invention, the smoke dust containing selenium sequentially carries out water absorption and first reduction processes, and the smoke dust containing selenium contains SeO₂Absorbing the smoke dust into H through water₂SeO₃Solution, then by SO in the soot₂The gas is reduced to elemental selenium. The drying process is not particularly limited in the present invention, and may be performed according to a process well known in the art. In the invention, the purity of the crude selenium is preferably 85-99%.

After the calcine is obtained, the calcine is mixed with sulfuric acid solution, and the mixture is subjected to oxygen pressure acid leaching to obtain a leaching solution containing copper and tellurium and anode mud with copper, selenium and tellurium removed. In the invention, the acidity of the sulfuric acid solution is preferably 100-140 g/L, and more preferably 120-130 g/L; the dosage ratio of the sulfuric acid solution to the calcine is preferably (5-8) L:1kg, and more preferably (6-7) L:1 kg.

In the invention, the temperature of the oxygen pressure acid leaching is preferably 100-150 ℃, more preferably 120-130 ℃, and the leaching time is preferably 0.5-4 h, more preferably 0.5-1 h; the leaching pressure is preferably 0.8-1.2 MPa, and more preferably 0.9-1.0 MPa. In the invention, the decoppering rate of the oxygen pressure acid leaching step is more than or equal to 98 percent.

After the oxygen pressure acid leaching is completed, the obtained materials are preferably separated to obtain a leaching solution containing copper and tellurium and anode mud with copper, selenium and tellurium removed. The process of the separation is not particularly limited in the present invention, and solid-liquid separation can be performed according to a process well known in the art.

After the leaching solution containing copper and tellurium is obtained, the leaching solution containing copper and tellurium is mixed with copper powder for secondary reduction, and copper and tellurium slag and copper sulfate solution are obtained. In the invention, the copper powder is used in an excessive amount relative to the leaching solution containing copper and tellurium; in the embodiment of the invention, the dosage of the copper powder relative to the leaching solution containing copper and tellurium is specifically 80 g/L.

The process of mixing the leaching solution containing copper and tellurium and copper powder is not particularly limited, and the materials are uniformly mixed according to the process well known in the art. The present invention is not particularly limited with respect to the specific conditions for the reduction, and the reduction may be carried out according to a procedure well known in the art. After the second reduction is completed, the invention preferably filters the obtained product to obtain copper-tellurium slag and copper sulfate solution.

In the second reduction process, copper powder replaces copper and tellurium to form copper telluride slag, tellurium and copper are separated in a compound form, and formed copper sulfate solution is separated and recycled.

And after the anode mud for removing copper, selenium and tellurium is obtained, mixing the anode mud for removing copper, selenium and tellurium with first charcoal, and carrying out low-temperature vacuum carbothermic reduction to obtain an arsenic oxide volatile matter and arsenic-removed anode mud. In the invention, the mixing of the anode mud of copper-removing selenium tellurium and the first charcoal preferably further comprises adding a binder, pelletizing, drying the obtained spherical material, and performing low-temperature vacuum carbothermic reduction. In the present invention, the binder is preferably starch, and the amount of the binder is not particularly limited, and may be adjusted according to actual needs. The pelletizing process is not particularly limited in the present invention and may be performed according to a process known in the art. In the present invention, the drying process is preferably performed at 60 ℃ for 2 hours and then at 160 ℃ for 2 hours.

In the invention, the mass of the first charcoal is preferably 20-35%, more preferably 25-30% of the mass of the anode mud of the copper-removed selenium tellurium, and the temperature of the low-temperature vacuum carbothermic reduction is 400-550 ℃, preferably 450-500 ℃; the system pressure of the low-temperature vacuum carbothermic reduction is preferably 1-50 Pa, more preferably 10-30 Pa, and the time is preferably 2-6 h, more preferably 3-4 h. In the present invention, the low-temperature vacuum carbothermic reduction is preferably performed in a vacuum furnace, and the vacuum furnace is not particularly limited to the above vacuum furnace, and may be a vacuum furnace known in the art.

And after the low-temperature vacuum carbothermic reduction is finished, collecting arsenic oxide volatile matters on a condensation cover, and simultaneously obtaining the arsenic-removed anode mud.

After the arsenic-removed anode mud is obtained, the arsenic-removed anode mud is subjected to high-temperature vacuum carbothermic reduction to obtain lead-bismuth mixed volatile matters and gold, silver and antimony-rich residues. In the present invention, before performing the high-temperature vacuum carbothermic, it is preferable to further comprise mixing the dearsenifying anode slime with a second charcoal; the mass of the second charcoal is preferably 0-10% of that of the arsenic-removed anode mud, and more preferably 1-5%. The present invention preferably determines the amount of the second charcoal based on the remaining amount of the first charcoal used in the low temperature vacuum carbothermic reduction step, and preferably does not add the second charcoal when the remaining amount of the first charcoal is sufficient to ensure sufficient high temperature vacuum carbothermic reduction; the present invention preferably detects the remaining amount of the first charcoal after performing the low temperature vacuum carbothermic reduction using a method well known in the art to determine the added amount of the second charcoal.

In the mixing process of the arsenic-removed anode mud and the second charcoal, preferably, after adding a binder, pelletizing, drying the obtained spherical material, and performing high-temperature vacuum carbothermic reduction; the type and amount of the binder, and the pelletizing and drying processes are preferably the same as those of the low-temperature vacuum carbothermic reduction process, and are not described in detail herein.

In the invention, the temperature of the high-temperature vacuum carbothermic reduction is 850-1100 ℃, and preferably 900-1000 ℃; the system pressure of the high-temperature vacuum carbothermic reduction is preferably 1-50 Pa, and more preferably 10-30 Pa; the time is preferably 2 to 6 hours, and more preferably 3 to 5 hours. In the invention, the high-temperature vacuum carbothermic reduction is preferably carried out in a vacuum furnace, after the high-temperature vacuum carbothermic reduction is completed, lead and bismuth in the dearsenified anode mud are volatilized in the form of compounds or simple substances (such as lead oxide, lead sulfide and lead bismuth antimony) and enter volatile matters to be recovered in a condensation disc, the volatile matters can be returned to a lead bottom blowing smelting system for recovery, the lead and bismuth are reduced into crude metal, silver is supplemented by lead and then enters the crude metal, the removal efficiency of the lead and bismuth is ensured, the loss of the silver is avoided, the residue is rich in precious metals of gold, silver and antimony, and also comprises metal barium. The process for recovering the lead bottom blowing smelting system is not particularly limited, and the process can be carried out according to the processes well known in the field.

After the gold and silver-rich antimony residues are obtained, the invention carries out vacuum distillation on the gold and silver-rich antimony residues to obtain silver and antimony volatiles and gold-rich residues. In the invention, the temperature of the vacuum distillation is preferably 1300-1500 ℃, and more preferably 1400-1500 ℃; the system pressure is preferably 1-50 Pa, and more preferably 1-10 Pa; the time is preferably 6 to 8 hours, and more preferably 6.5 to 7.5 hours.

In the distillation process, silver and antimony in the gold and silver antimony-rich residue volatilize into volatile matters, most of gold is enriched in the residue, and the silver and antimony volatile matters and the gold-rich residue are obtained. The process for recovering silver antimony volatiles is not particularly limited in the present invention and may be recovered according to processes well known in the art.

After obtaining the silver-antimony volatile matter, oxidizing and refining the silver-antimony volatile matter to obtain antimony oxide volatile matter and crude silver, and electrolyzing the crude silver to obtain the electric silver. In the invention, the temperature of the oxidation refining is preferably 950-1100 ℃, and more preferably 1000-1050 ℃; the time is preferably 3 to 10 hours, and more preferably 5 to 8 hours. In the oxidation refining process, antimony in the silver-antimony volatile matter is volatilized into the volatile matter in the form of antimony oxide, and crude silver is obtained at the same time. The process of recovering antimony oxide volatiles and the process of subjecting the crude silver to electrolysis are not particularly limited in the present invention and may be performed according to processes well known in the art.

And after obtaining the gold-rich residue, carrying out chlorination gold separation, third reduction and electrolysis on the gold-rich residue in sequence to obtain the electrogold. In the present invention, the process of gold chloride separation, third reduction and electrolysis preferably comprises: and (3) carrying out chlorination gold separation on the gold-rich residues, introducing sulfur dioxide into the obtained gold liquid, reducing, and electrolyzing the obtained gold powder to obtain the electrogold. The reagent and the specific process for the chlorination and the gold separation are not particularly limited and can be carried out according to the well-known process in the field; the amount of the introduced sulfur dioxide, the specific process of reduction and the process of gold powder electrolysis are not particularly limited in the invention, and the process is performed according to the processes well known in the art.

In the invention, the gold separation slag obtained by the chlorination gold separation is used for recovering barium sulfate; the process for recovering barium sulfate according to the present invention is not particularly limited, and may be performed according to a process known in the art.

FIG. 1 is a flow chart of a method for recovering valuable metals from copper anode slime, and as shown in FIG. 1, the method carries out sulfating roasting on the copper anode slime to obtain selenium-containing smoke dust (flue gas) and roasted sand; absorbing and reducing the selenium-containing smoke dust by water to obtain crude selenium; carrying out oxygen pressure acid leaching on the calcine to obtain a leaching solution containing copper and tellurium and anode mud with copper, selenium and tellurium removed; carrying out displacement reduction on the leaching solution containing copper and tellurium and copper powder to obtain copper and tellurium slag (copper telluride slag) and copper sulfate solution (copper-containing solution); carrying out low-temperature vacuum carbothermic reduction on the anode mud subjected to copper removal, selenium removal and tellurium removal to obtain an arsenic oxide volatile matter and arsenic removal anode mud (residue); carrying out high-temperature vacuum carbothermic reduction on the dearsenified anode mud to obtain lead-bismuth mixed volatile matters and gold, silver and antimony-rich residues; carrying out vacuum distillation on the gold-silver-antimony-rich residues to obtain silver-antimony volatile matters and gold-rich residues; oxidizing and refining the silver-antimony volatile matter to obtain antimony oxide volatile matter and crude silver, and electrolyzing the crude silver to obtain electrolytic silver; the gold-rich residues are subjected to chlorination gold separation in sequence, and the obtained gold separation liquid is subjected to SO separation₂Reducing, electrolyzing the obtained gold powder to obtain electrogilt; and (4) recycling barium sulfate from the gold slag obtained by chlorination and gold separation.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

2500kg of a composition consisting essentially of Pb 6.18%, Sb 4.2%, As 5.82%, Bi 7.28%, Cu 14.18%, Ag 10.65%, Se 4.03%, Te 1.02%, Ni 6.16% and Au 529After large-particle impurities are sieved out of 5g/t copper anode mud, slurrying the copper anode mud and concentrated sulfuric acid (98%) in a stirring tank according to the mass ratio of 1:1, feeding the slurried anode mud into a rotary kiln, controlling the kiln head temperature of the rotary kiln to be 300 ℃, the temperature in the kiln to be 500 ℃, the kiln tail temperature to be 600 ℃, and carrying out sulfating roasting at the roasting temperature of 500 ℃ for 4 hours to obtain the product containing SeO₂Flue dust and calcine, containing SeO₂Absorbing the smoke dust into H through water₂SeO₃SO in solution, by smoke₂Reducing the gas into elemental selenium, and drying to obtain crude selenium (with the purity of 89%);

soaking the calcine in dilute sulfuric acid (acidity 100g/L), carrying out oxygen pressure acid leaching (temperature 120 ℃, leaching time 30min, leaching pressure 0.8Mpa and liquid-solid ratio 5L:1kg), and separating to obtain a copper-tellurium-containing leachate and copper-selenium-tellurium-removed anode mud (Pb 12.11%, Sb 4.85%, As 9.35%, Bi 12.92%, Cu 0.05%, Ag 11.65%, Se0.71%, Te 1.46%, Ni0.41% and Au 936.5 g/t);

adding excessive copper powder into the leaching solution containing copper and tellurium according to the proportion of 80g/L for reduction treatment, and filtering to obtain copper and tellurium slag and a copper sulfate solution;

100.00g of the copper-removing, selenium-removing and tellurium anode slime (Pb 12.11%, Sb 4.85%, As 9.35%, Bi 12.92%, Cu 0.05%, Ag 11.65%, Se0.71%, Te 1.46%, Ni0.41% and Au 936.5g/t) is mixed with 30g of charcoal, 3g of starch adhesive is mixed for pelletizing, the obtained spherical material is dried at 60 ℃ for 2h and then dried at 160 ℃ for 2h, then low-temperature carbothermic reduction is carried out in a vacuum furnace, the reaction temperature is 550 ℃, the system pressure is 1-10 pa, after heat preservation is carried out for 4h, arsenic oxide volatile matters are collected on a condensation hood, 82.92g of residue (dearsenization anode slime) is obtained, wherein arsenic is reduced from 9.35% in the raw material to 0.48%, and 95.82% of arsenic is removed;

mixing the dearsenified anode mud with 3g of starch binder for pelletizing, drying the obtained spherical material at 60 ℃ for 2 hours, then drying the spherical material at 160 ℃ for 2 hours, carrying out high-temperature carbothermic reduction in a vacuum furnace, keeping the reaction temperature at 1100 ℃ for 2 hours, keeping the system pressure at 1-10 pa, collecting lead-bismuth mixed volatile matters on a condensation disc, and simultaneously obtaining residues rich in gold, silver and antimony;

carrying out vacuum distillation on the gold-silver-antimony-rich residues at 1400 ℃ for 6h to obtain silver-antimony volatile matters and gold-rich residues;

carrying out oxidation refining on the silver-antimony volatile substance at 1000 ℃ for 3h to obtain an antimony oxide volatile substance and crude silver, and electrolyzing the crude silver to obtain electrolytic silver;

and (4) carrying out chlorination gold separation, third reduction and electrolysis on the gold-rich residue in sequence to obtain the electrogold.

Detecting the components and the contents of the obtained lead-bismuth mixed volatile matter and the gold-silver-antimony-rich residue, wherein the lead and the bismuth in the residue are reduced to 0.77 percent and 0.039 percent from 12.11 percent and 12.92 percent in the raw materials, and the removal rate reaches 97.12 percent and 99.87 percent; 2.5% of the silver in the copper anode slime went into the volatiles and no gold was detected from the volatiles.

Characterization test

1) XRD testing was performed on the arsenic oxide volatiles and residues (dearsenifying sludge) obtained after the low-temperature carbothermic reduction in example 1, and the obtained results are shown in FIGS. 2 and 3; wherein, FIG. 2 is an XRD spectrum of volatile arsenic oxide; FIG. 3 is an XRD spectrum of the residue; as can be seen from FIGS. 2 to 3, the volatile matter is arsenic oxide with a single phase, and the lead and bismuth in the residue are not completely removed.

2) XRD test is carried out on the lead bismuth mixed volatile matter and the gold, silver and antimony-rich residue obtained after the high-temperature carbothermic reduction in the embodiment 1, and the obtained result is shown in figure 4 and figure 5; wherein, FIG. 4 is an XRD spectrum of the volatile; FIG. 5 is an XRD spectrum of antimony residue rich in gold and silver; as can be seen from FIGS. 4-5, the phase of bismuth does not appear in the residue proves that the removal of arsenic bismuth can be achieved by two-stage carbothermic reduction, the noble metal in the residue is mainly silver-antimony compound, and the amount of added charcoal is excessive, thereby providing theoretical support for the extraction of silver and antimony by the latter stage of vacuum distillation.

3) The elemental contents of the vacuum carbothermic stage of example 1 were examined and the results are shown in table 1.

TABLE 1 element balance (/ g) in the vacuum carbothermic stage of example 1

As can be seen from table 1, there is almost no loss of noble metal in the whole carbothermic reduction process (low-temperature carbothermic reduction and high-temperature carbothermic reduction), and there is a loss of silver in table 1, the analysis reason is mainly caused by analysis error, and because the experimental scale is small, and at the same time, a part of product remains in the equipment in the distillation process to cause errors. As can be seen from Table 1, the bismuth content of the residue obtained by the two carbothermic reductions was very low, which significantly reduced the difficulty and the treatment capacity of the subsequent noble metal purification procedures. Simultaneously realizes the removal of more than 96 percent of arsenic and the direct recovery of nearly 99 percent of arsenic.

Example 2

Screening 2500kg of copper anode mud with the main components of 6.18 percent of Pb, 4.2 percent of Sb, 5.82 percent of As, 7.28 percent of Bi, 14.18 percent of Cu, 10.65 percent of Ag, 4.03 percent of Se, 1.02 percent of Te, 6.16 percent of Ni and 529.5g/t of Au to remove large-particle inclusions, slurrying the copper anode mud and concentrated sulfuric acid (98 percent) in a stirring tank according to the mass ratio of 1:1, feeding the slurried anode mud into a rotary kiln, controlling the kiln head temperature of the rotary kiln to be 300 ℃, the temperature in the kiln to be 500 ℃, the temperature at the kiln tail to be 600 ℃, carrying out sulfating roasting, controlling the roasting temperature to be 500 ℃ and the time to be 4 hours, and obtaining the SeO-containing anode mud₂Flue dust and calcine, containing SeO₂Absorbing the smoke dust into H through water₂SeO₃SO in solution, by smoke₂Reducing the gas into elemental selenium, and drying to obtain crude selenium (the purity is 90%);

soaking the calcine in dilute sulfuric acid (acidity 100g/L), carrying out oxygen pressure acid leaching (temperature 120 ℃, leaching time 30min, leaching pressure 0.8Mpa and liquid-solid ratio 5L:1kg), and separating to obtain a copper-tellurium-containing leachate and copper-selenium-tellurium-removed anode mud (Pb 12.11%, Sb 4.85%, As 9.35%, Bi 12.92%, Cu 0.05%, Ag 11.65%, Se0.71%, Te 1.46%, Ni0.41% and Au 936.5 g/t);

adding excessive copper powder into the leaching solution containing copper and tellurium according to the proportion of 80g/L for reduction treatment, and filtering to obtain copper and tellurium slag and a copper sulfate solution;

1005.6g of the copper-removing, selenium-removing and tellurium anode slime (Pb 12.11%, Sb 4.85%, As 9.35%, Bi 12.92%, Cu 0.05%, Ag 11.65%, Se 0.71%, Te 1.46%, Ni 0.41% and Au 936.5g/t) is mixed with 300g of charcoal, 30g of starch adhesive is mixed to carry out pelletizing, the obtained spherical material is dried at 60 ℃ for 2 hours and then dried at 160 ℃ for 2 hours, then low-temperature carbothermic reduction is carried out in a vacuum furnace, the reaction temperature is 550 ℃, the system pressure is 1-10 pa, after heat preservation is carried out for 2 hours, arsenic oxide volatile matters (arsenic oxide with single phase and containing arsenic 63.42%) are collected on a condensation cover, and residue (arsenic-removing anode slime) 810g is obtained, wherein arsenic is reduced to 0.32% from 9.35% in the raw material, and arsenic removal of 97.49% is realized;

mixing the dearsenified anode mud with 30g of starch binder for pelletizing, drying the obtained spherical material at 60 ℃ for 2 hours, then drying the spherical material at 160 ℃ for 2 hours, carrying out high-temperature carbothermic reduction in a vacuum furnace, keeping the reaction temperature at 1100 ℃ for 4 hours, keeping the system pressure at 1-10 pa, collecting lead-bismuth mixed volatile matters on a condensation disc, and simultaneously obtaining residues rich in gold, silver and antimony;

carrying out vacuum distillation on the gold-silver-antimony-rich residues at 1400 ℃ for 6h to obtain silver-antimony volatile matters and gold-rich residues;

carrying out oxidation refining on the silver-antimony volatile substance at 1000 ℃ for 3h to obtain an antimony oxide volatile substance and crude silver, and electrolyzing the crude silver to obtain electrolytic silver;

and (4) carrying out chlorination gold separation, third reduction and electrolysis on the gold-rich residue in sequence to obtain the electrogold.

Detecting the components and the contents of the obtained lead-bismuth mixed volatile matter and the gold-silver-antimony-rich residue, wherein the lead and the bismuth in the residue are reduced to 0.47 percent and 0.029 percent from 12.11 percent and 12.92 percent in the raw materials, and the removal rate reaches 98.12 percent and 99.89 percent; 3.1% of the silver in the copper anode slime went into the volatiles and no gold was detected from the volatiles.

Characterization test

4) XRD testing was performed on the volatile arsenic oxide and the residue (arsenic-removed anode sludge) obtained after the low-temperature carbothermic reduction in example 2, and the obtained results are shown in FIG. 6; wherein a is an XRD spectrogram of the volatile arsenic oxide; b is an XRD spectrum of the residue; as can be seen from FIG. 6, the volatile was arsenic oxide with a single phase, and the lead and bismuth in the residue were not removed.

5) XRD test is carried out on the lead bismuth mixed volatile matter and the gold, silver and antimony-rich residue obtained after the high-temperature carbothermic reduction in the embodiment 2, and the obtained result is shown in figure 7; wherein a is an XRD spectrogram of the volatile matter; b is an XRD spectrum of the residue; as can be seen in FIG. 7, the phase of bismuth does not appear in the residue, which demonstrates that arsenic removal from bismuth can be achieved by two-stage carbothermic reduction, and that the noble metal in the residue is mainly in the form of a silver-antimony compound, which provides a theoretical support for the extraction of silver and antimony by the subsequent vacuum distillation.

6) The elemental contents of example 2 at the vacuum carbothermic stage were determined and the results are shown in table 2.

TABLE 2 element balance (/ g) in the vacuum carbothermic reduction zone of example 2

A-represents no detection and a blank represents no detection.

As can be seen from Table 2, gold was not detected in the volatile during the low temperature vacuum carbothermic reduction and high temperature vacuum carbothermic reduction stages, indicating that the residue obtained from the high temperature vacuum carbothermic reduction is enriched in all gold elements.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.