Method for treating copper anode slime through combination of reduction smelting, vacuum distillation and oxidation refining

Abstract

The invention discloses a method for treating copper anode slime through combination of reduction smelting, vacuum distillation and oxidation refining. The method comprises the following steps: firstly, adding a reducing agent and a slagging constituent into tellurium slag obtained by removing copper, selenium and tellurium from copper anode slime by a conventional method, and uniformly mixing to obtain a mixed material; the obtained mixed material is added into a converter to be subjected to a heating reduction smelting reaction, and reducing slag and high-gold precious lead are generated in the converter; the method comprises the following steps: putting high-gold precious lead into a vacuum furnace for vacuum distillation, cooling after distillation, filling nitrogen for protection after cooling, and opening the vacuum furnace to discharge lead-bismuth alloy and residues when the pressure reaches the standard atmospheric pressure; and the obtained residues are placed in a refining furnace to be subjected to oxidation refining, and lead bismuth slag, tellurium slag, alloy slag and an alloy plate are generated. By means of the technical scheme, the direct recovery rate of precious metal is high, the field environment is good, the production cost is low, the additional value of by-products is high, and the technical problems existing in an existing copper anode slime treatment process can be effectively solved.

Description

1. Technical field:

[0001] The invention relates to the technical field of rare and precious metal recovery, and in particular to a method for treating copper anode mud by combining reduction smelting-vacuum distillation-oxidation refining. 2. Background technology:

[0002] At present, the production processes of copper anode mud are mainly wet process and Kaldo furnace process. The two processes are specifically introduced as follows:

[0003] 1. Wet process: When copper anode mud is treated by wet process, a large amount of hazardous chemicals such as sulfuric acid and a large amount of water are needed. Therefore, a large amount of wastewater will be generated during wet process, and the treatment cost is high. Therefore, the main copper anode mud treatment plants now mainly use the Kaldo furnace process.

[0004] 2. Kaldo furnace process: When copper anode mud is treated by the Kaldo furnace process, the anode mud reduction smelting and oxidation refining are carried out in the same furnace. The furnace temperature varies greatly, the life of the furnace bricks is short, and the amount of soot and slag is large in the oxidation refining stage, resulting in high energy consumption.

[0005] 3. Application of vacuum distillation technology in copper anode mud treatment: Vacuum distillation technology is a new type of multi-metal purification and separation technology developed in recent years. At present, in 2020, Henan Yuguang Gold and Lead Co., Ltd. applied for the invention patent of "A method for comprehensive recovery of bismuth, silver and copper metals using precious lead as raw material", which has been authorized, and its patent application number is CN202010909053.0. The patent mentions a vacuum distillation treatment process for precious lead produced by lead anode mud. The precious lead produced by lead anode mud and copper anode mud has a large difference in composition, and the precious lead production process is also very different. The oxidation refining treatment process of the vacuum distillation residue is different.

[0006] Therefore, how to solve the problems of high production cost when copper anode mud is treated by wet method and low direct recovery rate of gold and silver in copper anode mud treated by pyrometallurgical Kaldo furnace has become a technical problem that anode mud smelting R&D personnel need to solve urgently. 3. Summary of the invention:

[0007] Technical problem to be solved by the present invention: Based on the shortcomings of the existing copper anode mud treatment process, the present invention provides a method for treating copper anode mud by combining reduction smelting-vacuum distillation-oxidation refining. Treating copper anode mud using the technical solution of the present invention can effectively solve the technical problems existing in the existing copper anode mud treatment process.

[0008] In order to solve the above problems, the technical solution adopted by the present invention is:

[0009] The present invention provides a method for treating copper anode mud by combining reduction smelting-vacuum distillation-oxidation refining, the method comprising the following steps:

[0010] a. First, a reducing agent and a slag-forming agent are added to the tellurium separation slag and mixed thoroughly to obtain a mixed material; the obtained mixed material is added to a converter for heating and reduction smelting reaction (during the reduction smelting reaction, sulfate in the tellurium separation slag is decomposed, part of antimony and arsenic volatilizes into fly ash, part of antimony and arsenic reacts with oxygen and the slag-forming agent to form reduction slag, and gold, silver, copper, bismuth and lead form high-gold precious lead at the bottom of the furnace body), and after reaction, reduction slag and high-gold precious lead are generated in the converter;

[0011] b. releasing the high-precious lead generated in step a, and then putting it into a vacuum furnace for vacuum distillation (during the vacuum distillation, most of the lead and bismuth enter the volatiles to generate lead-bismuth alloy; other gold, silver and a small amount of lead remain in the residue), cooling after the distillation is completed, and nitrogen is filled for protection after cooling. When the pressure reaches the standard atmospheric pressure, the vacuum furnace is opened to release the generated lead-bismuth alloy and the residue;

[0012] c. placing the residue obtained in step b in a refining furnace for heating and melting. When the residue is completely melted, two oxygen blowing pipes are inserted into the melt to blow oxygen and stir the melt (to make the more active lead and bismuth in the alloy react with oxygen to generate lead-bismuth slag. The lead-bismuth slag has a higher melting point than the alloy and a lower density than the alloy, so it floats on the surface of the melt) to generate lead-bismuth slag, and the lead-bismuth slag is discharged from the slag discharge port by rotating the furnace body;

[0013] After sampling, observation and comparison (on-site alloy grade comparison table) or testing, when the silver content in the alloy reaches 60-70wt%, add caustic soda flakes to carry out tellurium slag making (tellurium slag making is mainly used to recover tellurium in the alloy. When making tellurium slag, tellurium oxide and caustic soda flakes combine to form sodium tellurite. The number of tellurium slag making is controlled according to the amount of alloy). When the tellurium content in the alloy drops below 0.5wt%, tellurium slag making is finished;

[0014] After the tellurium slag is made, a mixture of sodium nitrate and soda ash is added to carry out the alloy cleaning operation (the oxygen atoms produced by the thermal decomposition of sodium nitrate react with copper to produce copper oxide, and the copper oxide and soda ash combine to produce slag, which is released from the furnace and repeated many times). When the copper content in the alloy is less than 1%, it is taken out of the furnace and cast into an alloy plate suitable for electrolysis.

[0015] According to the above-mentioned method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining, the tellurium separation slag in step a is obtained by removing copper, selenium and tellurium from the copper anode mud by conventional methods.

[0016] According to the above-mentioned method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining, the tellurium separation slag in step a is first dried, and after drying, the moisture content in the tellurium separation slag is ≤5wt% and the particle size is ≤5cm.

[0017] According to the above-mentioned method of treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining, the reducing agent in step a is coke particles or coal powder, and its added amount accounts for 0.2 to 0.4 times the lead metal content in the tellurium slag; the slag-forming agent is soda ash, and its added amount accounts for 5 to 10% of the weight of the tellurium slag.

[0018] According to the above-mentioned method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining, in the reduction smelting reaction in step a, the furnace temperature is controlled to be 1000-1150° C.; the lead content of the obtained high-precious lead is 30-70wt%, the gold content is 1-3wt%, and the silver content is 10-30wt%.

[0019] According to the above-mentioned method of treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining, during the vacuum distillation process in step b, the negative pressure is controlled to be 10-30pa and the distillation power is 80-90Kwh; during cooling, the cooling water pressure is controlled to be 0.2-0.3Mpa.

[0020] According to the above-mentioned method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining, the lead content in the lead-bismuth alloy obtained in step b is 85-95wt%; the amount of gold metal in the obtained residue accounts for 100% of the raw material, the amount of silver metal accounts for more than 99.8% of the raw material, and the amount of lead metal accounts for 1-10% of the raw material.

[0021] According to the above-mentioned method for treating copper anode mud by combining reduction smelting-vacuum distillation-oxidation refining, the temperature is controlled at 850-950°C during the process of generating lead-bismuth slag in step c, the temperature is controlled at 900-1000°C during the slag discharge, the temperature is controlled at 900-1050°C during the process of making tellurium slag, and the temperature is controlled at 1100-1250°C during the alloy cleaning operation.

[0022] According to the above-mentioned method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining, in the mixture of sodium nitrate and soda ash in step c, the mass ratio of sodium nitrate to soda ash added is 3 to 4:1.

[0023] According to the above-mentioned method of treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining, the obtained tellurium slag contains 10-30wt% tellurium, the obtained lead-bismuth slag contains 30-70wt% lead, and the total content of gold and silver in the obtained alloy plate is greater than 98wt%, copper is less than 1wt%, bismuth is less than 0.1wt%, and tellurium is less than 0.15wt% (the obtained clean alloy slag is mainly alkali and copper oxides).

[0024] In the technical solution of the present invention, the reducing slag generated in the converter in step a is returned to the collection plant for processing and recovery of antimony and arsenic; the lead-bismuth alloy released in step b is returned to the lead electrolysis system for lead recovery; in step c, the surface pores are observed after cooling the alloy sample. If there are no pores or few pores in the alloy, it means that the oxygen blowing amount is insufficient and the oxygen blowing amount needs to be increased. If a large number of bubbles are released during the cooling process of the alloy, it means that the oxygen blowing is excessive and the oxygen blowing amount needs to be appropriately reduced.

[0025] The positive beneficial effects of the present invention are:

[0026] 1. In the technical solution of the present invention, the tellurium separation slag is subjected to deep reduction smelting to decompose the sulfate in the tellurium separation slag, and all the elements except antimony, arsenic and a small amount of lead are converted into elemental metals; during the reduction at this stage, almost all the valuable metals are reduced to precious lead, the yield of ash and slag is very low, and the metal loss is small.

[0027] 2. In the technical solution of the present invention, vacuum distillation equipment is used to separate base metals and purify precious metals; the physical separation carried out in a closed space during the vacuum distillation stage can achieve a gold and silver yield of 100%.

[0028] 3. In the technical solution of the present invention, oxidation refining is used to purify precious metals; the gold and silver grades of the materials before oxidation purification are high, the gold and silver smelting time is short, and the smelting loss is small.

[0029] 4. The technical solution of the present invention has a high direct recovery rate of precious metals. The main reasons are: 1) The valence state transformation of each element in the tellurium separation slag adopts a deep reduction process, and the ash and slag mass yield of this process is very low. 2) Since the bismuth and copper contents in the tellurium separation slag after selenium evaporation, copper removal and tellurium removal are greatly reduced, the precious lead produced by deep reduction is mainly lead in addition to precious metals. The boiling points of lead and precious metals are quite different. During vacuum distillation, the lead is separated very thoroughly, and the gold and silver content of the residue after separation is relatively high. 3) Vacuum distillation is carried out in a closed space, and the yield of gold and silver can reach 100%.

[0030] 5. Good on-site environment: The technical solution of the present invention adopts deep reduction and vacuum distillation. The amount of soot and slag produced in the smelting process is small. The distillation and separation stage is carried out in a closed space, and there is no dust on site, which is beneficial to environmental protection.

[0031] 6. Low production cost: The technical solution of the present invention has a short production process. By utilizing the low bismuth content in the tellurium separation slag, the residue produced by the vacuum furnace has a small amount of lead-bismuth slag in the oxidation refining process.

[0032] 7. High added value of by-products: The main by-product of the smelting process of the present invention is elemental lead containing more than 80% lead, which is easier to recover compared with the lead oxide produced by traditional smelting. 4. Description of the drawings:

[0033] Figure 1 The present invention discloses a process flow diagram of a method for treating copper anode mud by combining reduction smelting-vacuum distillation-oxidation refining. V. Specific implementation methods:

[0034] The present invention is further described below in conjunction with embodiments, but the protection scope of the technical solution of the present invention is not limited thereto.

[0035] Embodiment 1:

[0036] See attached Figure 1 The present invention adopts a method for treating copper anode mud by combining reduction smelting-vacuum distillation-oxidation refining, and the detailed steps are as follows:

[0037] a. Dry the tellurium slag obtained after copper anode mud is decoppered, deselenized and tellurized by conventional methods. The tellurium slag has a moisture content of 3wt% and a particle size of 0.5-5cm after drying. Take 3 tons of tellurium slag after drying, 300kg of coke pellets and 300kg of soda ash, mix them with a grab crane, and mix them to obtain a mixed material. Add the obtained mixed material into the converter after drying through the converter discharge port (after the converter is dried, the furnace temperature is controlled to be 1000-1100℃). After all the mixed materials are added, control the flow rate of the natural gas burner to 80-90Nm 3 / h and the air volume is controlled to be 10 times the natural gas flow rate to carry out material melting operation. After all the materials are melted, the furnace temperature is controlled to be 1000-1150°C, and reduction smelting operation is carried out under this condition (during the reduction smelting reaction, sulfate in the tellurium slag is decomposed, part of the antimony and arsenic volatilizes into the smoke, part of the antimony and arsenic reacts with oxygen and slag-making agent to form reduction slag, and gold, silver, copper, bismuth and lead form high-gold precious lead at the bottom of the furnace body); after melting, the reaction is carried out for 3 hours, and about 600kg of reduction slag and 2 pieces of high-gold precious lead (about 600kg each) are released; after analysis, the obtained high-gold precious lead contains 62% lead, 5.8% bismuth, 0.36% copper, 0.51% tellurium, 1.13% gold and 25.53% silver;

[0038] b. releasing the high-precious lead generated in step a, and then taking one of the lead and placing it in a vacuum furnace for vacuum distillation (during the vacuum distillation process, most of the lead and bismuth enter the volatiles to generate a lead-bismuth alloy; the other gold, silver and a small amount of lead remain in the residue), the vacuum degree is controlled to be 10-30pa, the cooling water pressure is controlled to be 0.2-0.3Mpa, the distillation power is adjusted to 85Kwh, and the distillation is performed for 6h; after the distillation is completed, the temperature is cooled for 3h, and then nitrogen is filled for protection. When the pressure reaches the standard atmospheric pressure, the lead-bismuth alloy is taken out from the collection bin, and the vacuum furnace is disassembled to take out the residue; 373kg of lead-bismuth alloy and 230kg of residue are generated (after analysis, the obtained lead-bismuth alloy contains 91.2% lead and 8.7% bismuth, and the obtained residue contains 26.5% lead, 0.76% bismuth, 0.95% copper, 1.35% tellurium, 3% gold, and 65.49% silver);

[0039] c. Crush the residue (6658 kg) produced by multiple furnaces in step b, and put it into the refining furnace after crushing. Control the flow rate of the natural gas burner to 60-80 Nm 3 / h and the air volume is controlled to be 10 times of the natural gas flow rate, and the temperature is raised to melt. After all the alloys are melted, the furnace temperature is controlled to be 850-950°C, and two oxygen blowing pipes are inserted into the melt to blow oxygen and stir the reaction (so that the more active lead and bismuth in the alloy react with oxygen to generate lead-bismuth slag. The lead-bismuth slag has a higher melting point than the alloy and a lower density than the alloy, so it floats on the surface of the melt). The lead-bismuth slag is discharged once after 2 hours of reaction. The temperature is controlled to be 900-1000°C during the discharge. The discharge of the lead-bismuth slag is completed after 8 hours, and a total of 1797 kg of lead-bismuth slag is discharged;

[0040] Then, 200 kg of caustic soda flakes were added into the furnace, and the temperature was controlled at 1000-1050° C. to make tellurium slag. The tellurium slag making operation was carried out again according to this method. After testing, the tellurium content was ≤0.5 wt%, and a total of 450 g of tellurium slag was released.

[0041] Then close the natural gas valve and air valve, add 37.5kg sodium nitrate and 12.5kg soda ash to the alloy to clean the alloy, stir the auxiliary materials in time after adding them to make the auxiliary materials and alloy fully contact, open the natural gas valve and air valve after 15 minutes, and control the natural gas burner flow rate to 80-100Nm 3 / h and the air volume is controlled at 10 times the natural gas flow rate, so that the temperature is controlled at 1100-1200℃ for alloy cleaning operation, react for 2h to release the alloy cleaning slag, and perform alloy cleaning operation again according to this method, then take samples to observe the color of the alloy sample to meet the furnace discharge standard, drill the alloy sample on the drilling machine, and find that the drilled alloy is in the form of wire, and start to prepare for furnace discharge. Before furnace discharge, bake the crucible at the furnace mouth for 2h, and the furnace temperature rises to 1150-1250℃ to start furnace discharge, and a total of 4550kg of alloy plates are produced. After testing, the alloy plate contains 4.2% gold, 94.8% silver, 0.43% copper, 0.06% bismuth, and 0.09% tellurium.

[0042] Embodiment 2:

[0043] See attached Figure 1 The present invention adopts a method for treating copper anode mud by combining reduction smelting-vacuum distillation-oxidation refining, and the detailed steps are as follows:

[0044] a. Dry the tellurium slag obtained after copper anode mud is decoppered, deselenized and tellurized by conventional methods. The tellurium slag has a moisture content of 4wt% and a particle size of 0.5-5cm after drying. Take 3 tons of tellurium slag after drying, 300kg of coke pellets and 300kg of soda ash, mix them with a grab crane, and mix them to obtain a mixed material. Add the obtained mixed material into the converter after drying through the converter discharge port (after the converter is dried, the furnace temperature is controlled to be 1000-1100℃). After all the mixed materials are added, control the flow rate of the natural gas burner to 80-90Nm 3 / h and the air volume is controlled to be 10 times the natural gas flow rate, and the material melting operation is carried out. After all the materials are melted, the furnace temperature is controlled to be 1000-1150°C, and the reduction smelting operation is carried out under this condition (in the reduction smelting reaction process, the sulfate in the tellurium slag is decomposed, part of the antimony and arsenic volatilizes into the smoke, part of the antimony and arsenic reacts with oxygen and slag-making agent to form reduction slag, and gold, silver, copper, bismuth and lead form high-gold precious lead at the bottom of the furnace body); after melting, the reaction is carried out for 3 hours, and about 600kg of reduction slag and 2 pieces of high-gold precious lead (about 600kg each) are released; after analysis, the obtained high-gold precious lead contains 64.8% lead, 5.5% bismuth, 0.34% copper, 0.49% tellurium, 1.27% gold and 26.64% silver;

[0045] b. Release the high-precious lead generated in step a, then take one of them and place it in a vacuum furnace for vacuum distillation (during the vacuum distillation process, most of the lead and bismuth enter the volatiles to generate lead-bismuth alloy; other gold, silver and a small amount of lead remain in the residue), the vacuum degree is controlled to 10-30pa, the cooling water pressure is controlled to 0.2-0.3Mpa, the distillation power is adjusted to 85Kwh, and the distillation is performed for 6h; after the distillation is completed, cool down for 3h, and then fill with nitrogen for protection. When the pressure reaches the standard atmospheric pressure, open the collection bin to take out the volatile lead-bismuth alloy, disassemble the vacuum furnace to take out the residue; 363kg of lead-bismuth alloy and 240kg of residue are generated (after analysis, the obtained lead-bismuth alloy contains 89.9% lead and 8.4% bismuth, and the obtained residue contains 26.5% lead, 0.76% bismuth, 0.95% copper, 1.35% tellurium, 3% gold, and 67.49% silver);

[0046] c. Crush 7658 kg of the residue produced by multiple furnaces in step b, put it into the refining furnace after crushing, and control the flow rate of the natural gas burner to 60-80 Nm 3 / h and the air volume is controlled to be 10 times of the natural gas flow rate, and the temperature is raised to melt. After all the alloys are melted, the furnace temperature is controlled to be 850-950°C, and two oxygen blowing pipes are inserted into the melt to blow oxygen and stir the reaction (so that the more active lead and bismuth in the alloy react with oxygen to generate lead-bismuth slag. The lead-bismuth slag has a higher melting point than the alloy and a lower density than the alloy, so it floats on the surface of the melt). The lead-bismuth slag is discharged once after 2 hours of reaction. The temperature is controlled to be 900-1000°C when the lead-bismuth slag is discharged. The discharge of the lead-bismuth slag is completed after 8 hours, and a total of 1210 kg of lead-bismuth slag is discharged;

[0047] Then, 200 kg of caustic soda flakes were added into the furnace, and the temperature was controlled at 1000-1050°C to make tellurium slag. The tellurium slag making operation was carried out again according to this method. After testing, the tellurium content was ≤0.5 wt%, and a total of 420 kg of tellurium slag was released.

[0048] Then close the natural gas valve and air valve, add 37.5kg sodium nitrate and 12.5kg soda ash to the alloy to clean the alloy, stir the auxiliary materials in time after adding them to make the auxiliary materials and alloy fully contact, open the natural gas valve and air valve after 15 minutes, and control the natural gas burner flow rate to 80-100Nm 3 / h and the air volume is controlled at 10 times the natural gas flow rate, so that the temperature is controlled at 1100-1200℃ for alloy cleaning operation, react for 2h to release the alloy cleaning slag, and perform alloy cleaning operation again according to this method, then take samples to observe the color of the alloy sample to meet the furnace discharge standard, drill the alloy sample on the drilling machine, and find that the drilled alloy is in the form of wire, and start to prepare for furnace discharge. Before furnace discharge, bake the crucible at the furnace mouth for 2h, and the furnace temperature rises to 1150-1250℃ to start furnace discharge, and a total of 5395kg of alloy plates are produced. After testing, the alloy plate contains 4.3% gold, 94.2% silver, 0.53% copper, 0.08% bismuth, and 0.07% tellurium.

[0049] Embodiment 3:

[0050] See attached Figure 1 The present invention adopts a method for treating copper anode mud by combining reduction smelting-vacuum distillation-oxidation refining, and the detailed steps are as follows:

[0051] a. Dry the tellurium slag obtained after copper anode mud is decoppered, deselenized and tellurized by conventional methods. The tellurium slag has a moisture content of 4.5wt% and a particle size of 0.5-5cm after drying. Take 3 tons of tellurium slag after drying, 300kg of coke pellets and 300kg of soda ash, mix them with a grab crane, and mix them to obtain a mixed material. Add the obtained mixed material into the converter after drying through the converter discharge port (after the converter is dried, the furnace temperature is controlled to be 1000-1100℃). After all the mixed materials are added, control the flow rate of the natural gas burner to 80-90Nm 3 / h and the air volume is controlled to be 10 times the natural gas flow rate to carry out material melting operation. After all the materials are melted, the furnace temperature is controlled to be 1000-1150°C, and reduction smelting operation is carried out under this condition (during the reduction smelting reaction, sulfate in the tellurium slag is decomposed, part of the antimony and arsenic volatilizes into the smoke, part of the antimony and arsenic reacts with oxygen and slag-making agent to form reduction slag, and gold, silver, copper, bismuth and lead form high-gold precious lead at the bottom of the furnace body); after melting, the reaction is carried out for 3 hours, and about 600kg of reduction slag and 2 pieces of high-gold precious lead (about 600kg each) are released; after analysis, the obtained high-gold precious lead contains 64.8% lead, 5.4% bismuth, 0.35% copper, 0.59% tellurium, 1.37% gold and 26.84% silver;

[0052] b. Release the high-precious lead generated in step a, then take one of them and place it in a vacuum furnace for vacuum distillation (during the vacuum distillation process, most of the lead and bismuth enter the volatiles to generate lead-bismuth alloy; other gold, silver and a small amount of lead remain in the residue), the vacuum degree is controlled to 10-30pa, the cooling water pressure is controlled to 0.2-0.3Mpa, the distillation power is adjusted to 85Kwh, and the distillation is performed for 6h; after the distillation is completed, cool down for 3h, and then fill with nitrogen for protection. When the pressure reaches the standard atmospheric pressure, open the collection bin to take out the lead-bismuth alloy, disassemble the vacuum furnace to take out the residue; 357kg of volatile lead-bismuth alloy and 244kg of residue are generated (after analysis, the obtained lead-bismuth alloy contains 87.9% lead and 7.4% bismuth, and the obtained residue contains 25.5% lead, 0.75% bismuth, 1.05% copper, 1.45% tellurium, 3.2% gold, and 65.49% silver);

[0053] c. Crush 7456 kg of the residue produced by multiple furnaces in step b, put it into the refining furnace after crushing, and control the flow rate of the natural gas burner to 60-80 Nm 3 / h and the air volume is controlled to be 10 times of the natural gas flow rate, and the temperature is raised to melt. After all the alloys are melted, the furnace temperature is controlled to be 850-950°C, and two oxygen blowing pipes are inserted into the melt to blow oxygen and stir the reaction (so that the more active lead and bismuth in the alloy react with oxygen to generate lead-bismuth slag. The lead-bismuth slag has a higher melting point than the alloy and a lower density than the alloy, so it floats on the surface of the melt). The lead-bismuth slag is discharged once after 2 hours of reaction. The temperature is controlled to be 900-1000°C when the lead-bismuth slag is discharged. The discharge of the lead-bismuth slag is completed after 8 hours, and a total of 1950kg of lead-bismuth slag is discharged;

[0054] Then, 200 kg of caustic soda flakes were added into the furnace, and the temperature was controlled at 1000-1050°C to make tellurium slag. According to this method, the tellurium slag making operation was performed again. After testing, the tellurium content was ≤0.5 wt%, and a total of 540 kg of tellurium slag was released.

[0055] Then close the natural gas valve and air valve, add 37.5kg sodium nitrate and 12.5kg soda ash to the alloy to clean the alloy, stir the auxiliary materials in time after adding them to make the auxiliary materials and alloy fully contact, open the natural gas valve and air valve after 15 minutes, and control the natural gas burner flow rate to 80-100Nm 3 / h and the air volume is controlled at 10 times the natural gas flow rate, so that the temperature is controlled at 1100-1200℃ for alloy cleaning operation, react for 2h to release the alloy cleaning slag, and perform alloy cleaning operation again according to this method, then take samples to observe the color of the alloy sample to meet the furnace discharge standard, drill the alloy sample on the drilling machine, and find that the drilled alloy is in the form of wire, and start to prepare for furnace discharge. Before furnace discharge, the crucible is baked at the furnace mouth for 2h, and the furnace temperature rises to 1150-1250℃ to start furnace discharge, and a total of 5166kg of alloy plates are produced. After testing, the alloy plate contains 4.6% gold, 94.3% silver, 0.51% copper, 0.05% bismuth, and 0.05% tellurium.

Claims

1. A method for treating copper anode mud by combining reduction smelting-vacuum distillation-oxidation refining, characterized in that: The method comprises the following steps: a. First, a reducing agent and a slag-forming agent are added to the tellurium separation slag and mixed thoroughly to obtain a mixed material; the obtained mixed material is added to a converter for heating, reduction and smelting reaction, and after the reaction, a reduction slag and high-precious lead are generated in the converter; b. releasing the high-precious lead generated in step a, and then putting it into a vacuum furnace for vacuum distillation. After the distillation is completed, cooling is performed, and nitrogen is filled for protection after cooling. When the pressure reaches the standard atmospheric pressure, the vacuum furnace is opened to release the generated lead-bismuth alloy and residue; c. placing the residue obtained in step b in a refining furnace for heating and melting. When the residue is completely melted, inserting two oxygen blowing pipes into the melt to blow oxygen and stir the melt to generate lead-bismuth slag, and discharging the lead-bismuth slag from the slag discharge port by rotating the furnace body; After sampling, observation, comparison or testing, when the silver content in the alloy reaches 60-70wt%, caustic soda flakes are added to start tellurium slag making. When the tellurium content in the alloy drops below 0.5wt%, tellurium slag making is finished. After the tellurium slag is made, a mixture of sodium nitrate and soda ash is added to clean the alloy. When the copper content in the alloy is less than 1%, it is taken out of the furnace and cast into an alloy plate suitable for electrolysis.

2. The method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining according to claim 1 is characterized in that: The tellurium separation slag described in step a is obtained by removing copper, selenium and tellurium from copper anode mud by conventional methods.

3. The method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining according to claim 1, characterized in that: The tellurium separation slag described in step a is first dried, and after drying, the moisture content of the tellurium separation slag is ≤5wt% and the particle size is ≤5cm.

4. The method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining according to claim 1 is characterized in that: The reducing agent in step a is coke particles or coal powder, and its added amount accounts for 0.2 to 0.4 times the lead metal content in the tellurium slag; the slag-forming agent is soda ash, and its added amount accounts for 5 to 10% of the weight of the tellurium slag.

5. The method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining according to claim 1, characterized in that: In the reduction smelting reaction described in step a, the furnace temperature is controlled to be 1000-1150° C.; the obtained high-precious lead has a lead content of 30-70wt%, a gold content of 1-3wt%, and a silver content of 10-30wt%.

6. The method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining according to claim 1, characterized in that: During the vacuum distillation process in step b, the negative pressure is controlled to be 10-30 Pa and the distillation power is controlled to be 80-90 Kwh; during cooling, the cooling water pressure is controlled to be 0.2-0.3 Mpa.

7. The method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining according to claim 1, characterized in that: The lead-bismuth alloy obtained in step b contains 85-95wt% lead; the amount of gold metal in the obtained residue accounts for 100% of the raw material, the amount of silver metal accounts for more than 99.8% of the raw material, and the amount of lead metal accounts for 1-10% of the raw material.

8. The method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining according to claim 1, characterized in that: In step c, the temperature is controlled at 850-950° C. during the process of generating the lead-bismuth slag, the temperature is controlled at 900-1000° C. during the slag discharge, the temperature is controlled at 900-1050° C. during the process of making the tellurium slag, and the temperature is controlled at 1100-1250° C. during the alloy cleaning operation.

9. The method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining according to claim 1, characterized in that: In the mixture of sodium nitrate and soda ash in step c, the mass ratio of sodium nitrate to soda ash added is 3 to 4:

1.

10. The method for treating copper anode mud by combined reduction smelting-vacuum distillation-oxidation refining according to claim 1, characterized in that: The obtained tellurium slag contains 10-30wt% tellurium, the obtained lead-bismuth slag contains 30-70wt% lead, and the total content of gold and silver in the obtained alloy plate is greater than 98wt%, copper is less than 1wt%, bismuth is less than 0.1wt%, and tellurium is less than 0.15wt%.

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