Wet process for recovering rare and precious metals

Abstract

The invention belongs to the field of rare and precious metal recovery, and particularly relates to a wet process for recovering rare and precious metals, which specifically comprises the steps of liquation refining, melt alkaline refining, alloy granulation, aqueous solution oxidation acid leaching, filter pressing, lead electrolysis, lead ingot casting, chloride-free bismuth refining and gold and silver refining. According to the method, valuable metals in the lead-bismuth-silver complex material are recovered by utilizing a wet process, so that the lead oxide pollution in the low-grade lead electrolysis process is reduced, the workload of cleaning lead anode slime is reduced, the use of chlorine in the bismuth refining process is reduced, and the recovery rate of lead and bismuth is improved. Air pollution can be effectively prevented, the lead recovery rate can be improved, energy can be saved, emission can be reduced, and certain superiority is achieved.

Description

Technical Field

[0001] The invention belongs to the field of rare and precious metal recovery, and in particular relates to a wet process for recovering rare and precious metals. Background Art

[0002] The main processes for processing lead-bismuth alloys containing high bismuth are: Chinese patent 201210229667X discloses a process for recovering valuable metals from precious metal smelting slag, comprising: smelting precious metal smelting slag and flux in a rotary top-blown furnace to obtain a lead-bismuth alloy, wherein the precious metal smelting slag comprises gold Au, silver Ag, bismuth Bi and lead Pb; subjecting the lead-bismuth alloy to a temperature of 60-110 A / m 2 The present invention adopts a rotary top-blown furnace as a smelting device and adjusts the flux ratio, so as to enrich valuable metals such as gold, silver, bismuth and lead in the lead-bismuth alloy, ensure that the content of gold, silver, bismuth and lead in the reduction slag is low, thereby improving the comprehensive recovery rate of gold, silver, bismuth and lead in the precious metal smelting slag.

[0003] Chinese patent 2023113969173 discloses a lead-bismuth alloy electrolysis process. A lead-bismuth alloy electrolysis process is disclosed. First, the front slag of the precious metal is smelted by a slag furnace to produce a lead-bismuth alloy crude lead containing 40%-50% lead and 20%-30% bismuth. After the alloy is produced, it is reasonably matched with crude lead, and the anode lead composition is controlled at the same time. After preliminary pyrometallurgical refining, the anode lead composition is controlled to contain 80%-85% lead, 10%-20% bismuth, 1%-2% antimony, and less than 0.05% copper. The present invention smelts the front slag of the precious metal by a slag furnace to produce a lead-bismuth alloy crude lead containing 50% lead and 30%-35% bismuth. After the alloy is produced, it is reasonably matched with crude lead, and the anode lead composition is controlled at the same time. After preliminary pyrometallurgical refining, the anode lead composition is controlled to contain 80%-85% lead, 10%-20% bismuth, 2% antimony, and less than 0.05% copper. The qualified lead liquid is poured into qualified anode plates through a casting machine, and the weight of the anode lead is controlled at 80-100kg / piece, and the thickness of the plate is controlled at 1-1.2cm to prevent the problem of plate breakage during the production process.

[0004] Chinese Patent 2022116152352 discloses a device and method for recovering refined lead from a high-bismuth lead-bismuth alloy. The present invention provides a device and method for recovering refined lead from a high-bismuth lead-bismuth alloy, including a lead electrolysis system and a bismuth electrolysis system. The lead electrolysis system and the bismuth electrolysis system share a silicon rectifier. The lead electrolysis system and the bismuth electrolysis system both include an electrolytic cell group, a high-level cell, a low-level cell, a circulating acid pipe and an acid pump. The electrolyte flows from the high-level cell into the electrolytic cell group through the circulating acid pipe, and then flows from the electrolytic cell group into the low-level cell, and then is pumped from the low-level cell into the high-level cell for circulation through the acid pump. The electrolytic cell group includes an electrolytic cell, an inter-cell conductive copper plate and a conductive large copper plate. The electrolytic cells between the inter-cell conductive copper plates are all connected in series to form a series. The bismuth electrolysis system realizes parallel connection of two series by adjusting the connection method of the conductive large copper plate. The current density of the bismuth electrolysis system is 1 / 2 of that of the lead electrolysis system. The isolation and independence of the circulating electrolyte of the bismuth electrolysis system is realized by valve control. The invention can process lead-bismuth alloys containing 15-35% bismuth, produce refined lead containing less than 30 ppm bismuth, and simultaneously produce anode mud containing 50-80% bismuth.

[0005] Chinese Patent 2022108569617 discloses a method for separating and recovering lead and bismuth from a lead-bismuth alloy, comprising the following steps: A) heating the lead-bismuth alloy to melt, and then oxidizing and powdering to obtain a mixture of lead oxide and bismuth oxide; B) subjecting the mixture to nitric acid leaching to obtain a reaction solution after reaction; C) subjecting the reaction solution to solid-liquid separation to obtain bismuth subnitrate and lead nitrate solution, evaporating and crystallizing the lead nitrate solution, and subjecting the obtained slurry to solid-liquid separation to obtain lead nitrate crystals.

[0006] Chinese Patent No. 2023116912054 discloses a method for the tiered comprehensive recycling of high-copper and high-bismuth multi-element alloys, which mainly comprises the following steps: crushing the high-copper and high-bismuth multi-element alloys to more than 150 meshes respectively; weighing a certain amount of the high-copper and high-bismuth multi-element alloy, mixing it with a certain concentration of sulfuric acid solution, and adding it to a high-pressure autoclave for high-temperature oxygen pressure leaching; subjecting the copper sulfate solution obtained by the high-temperature oxygen pressure leaching to cyclone electrolysis to obtain cathode copper, and drying the leached slag for reduction smelting; mixing the dried leached slag with a certain amount of reducing agent for reduction smelting to obtain a crude bismuth alloy; subjecting the obtained crude bismuth alloy to a vacuum distillation to separate tellurium from lead, bismuth, gold, silver and other precious metals to obtain refined tellurium and a primary high-bismuth alloy, and further subjecting the primary high-bismuth alloy to vacuum distillation to recover valuable metals such as lead, bismuth, gold, silver, etc.; subjecting the primary high-bismuth alloy to a secondary vacuum distillation to separate lead, bismuth and gold, silver and other precious metals to obtain a lead-bismuth alloy and a high-silver alloy, and the lead-bismuth alloy is sold externally, and the high-silver alloy continues to recover precious metals such as gold, silver, etc. The present invention uses high-temperature oxygen pressure leaching to achieve the separation and resource recovery of copper in the high-copper and high-bismuth multi-element alloy, and simultaneously uses a vacuum distillation method in a short process to achieve the separation of tellurium, lead, bismuth and precious metals such as gold and silver, thereby achieving efficient and short-process tiered comprehensive recovery and utilization of the high-copper and high-bismuth multi-element alloy.

[0007] Disadvantages of the above prior art 1) The lead content of lead-bismuth alloy is much lower than that of the lead anode in conventional lead electrolysis, resulting in a depleted lead ion concentration in the electrolyte and a significantly lower free acid concentration than in conventional lead electrolysis.

[0008] 2) The high bismuth content in lead-bismuth alloys causes the cathode current efficiency to be higher than the anode current efficiency during electrolysis, causing the lead ion concentration in the electrolyte to continue to decrease, and lead oxide is needed to supplement lead in the electrolyte. However, lead oxide is a hazardous waste material, and the price of commercial lead oxide is usually higher than that of electrolytic lead. The cost of supplementing lead is high, and this technology also has technical difficulties such as low yield and large losses.

[0009] 3) Lead-bismuth alloy contains bismuth and other impurities, which makes it difficult for the anode mud to fall off during electrolysis. When the lead-bismuth alloy residual electrode needs to be lifted out of the tank, it needs to be manually knocked and scraped to remove the hard shell of the anode mud on the surface of the residual electrode, which is labor-intensive.

[0010] 4) The lead content in the anode mud of lead-bismuth alloy electrolysis is relatively high, and the bismuth refining process requires chlorine gas to remove the lead, which poses certain environmental pollution problems. Summary of the invention

[0011] In order to overcome the shortcomings of the prior art, the present invention intends to provide a wet process for recovering rare and precious metals. The present invention solves the technical problems of low separation efficiency, high smelting cost, and environmental pollution of lead-bismuth alloys. The present invention is a green and efficient lead-bismuth alloy separation and refining technology, which greatly shortens the smelting process and reduces the smelting cost.

[0012] The technical solution of the present invention is: a wet process for recovering rare and precious metals, comprising the following steps: S1. Melting refining: adding the lead-bismuth alloy into a refining furnace to melt, and after the melting is completed, removing the slag on the surface of the melt to obtain a melting alloy melt; S2. Alkaline refining of the melt: When the total amount of arsenic and antimony in the melt is greater than 1%, alkaline refining is performed to remove arsenic, antimony and tin to obtain a de-arsenicized antimony alloy melt; when the antimony content in the melt is less than 6‰, the alloy granulation process is directly performed; S3 alloy granulation: the melt after step S2 is pumped into a casting furnace, the casting furnace is tilted, the melt is introduced into a granulator for granulation, and arsenic-free antimony alloy particles are obtained; S4. Aqueous solution oxidation acid leaching: The lead-bismuth alloy particles are placed in an acid leaching tank, stirred with a silicic acid solution, and then an oxidant is added; S5. Filtration: After the reaction is completed, the acid leaching liquid in the acid leaching tank is introduced into the intermediate tank, and then pumped into the filter press for filtration; S6. Lead electrolysis: The acid leaching solution is sent to the lead electrowinning cell or added to the lead-bismuth alloy electrolytic cell, and lead electrowinning or lead-bismuth alloy electrolysis produces cathode lead plates.

[0013] S7. Casting lead ingots: feeding the cathode lead plate into a lead casting furnace to melt and cast into lead ingots; S8. Chlorine-free bismuth refining: The filter cake discharged from the filter press is high-bismuth slag, which is sent to the bismuth refining process for refining to produce national standard bismuth ingots and silver-zinc shells; S9. Gold and silver refining: send the silver-zinc shells to the precious metal workshop for refining to produce national standard gold and silver ingots.

[0014] Preferably, the operating temperature of the melt refining in step S1 is 600-650°C.

[0015] Preferably, the steps of alkaline refining to remove arsenic, antimony and tin in step S2 are: A1. Control the temperature of the alloy melt obtained by S1 to be between 610 and 620°C; A2. Insert the oxygen tube 40-50 cm below the surface of the molten alloy and start mechanical stirring; A3. Add alkali into the stirring vortex, and remove the arsenic antimony slag when dry slag is formed on the surface of the melt; A4. Depending on the content of arsenic, antimony and tin, the entire operation time is about 6 to 10 hours; A5. When arsenic is less than 0.01% and antimony is less than 0.6%, it indicates that the operation has reached its end point. Close the oxygen valve, stop stirring, and remove the arsenic and antimony slag.

[0016] Preferably, in step S3, the operating temperature of the casting furnace is controlled at 500-550°C.

[0017] Preferably, the size of the arsenic-free antimony alloy particles in step S3 is controlled to be 3-6 mm.

[0018] Preferably, the steps of aqueous solution oxidation acid leaching operation in step S4 are: B1. Loading the dearsenicated antimony alloy particles into the acid leaching tank; B2. Add silicic acid and start stirring; B3. After stirring for 1 to 5 minutes, start adding hydrogen peroxide at a rate of 90 to 120 l / h for 1.5 to 2.5 hours; B4. The reaction temperature is below 80-95℃. If the temperature is too high, close the hydrogen peroxide valve to reduce the addition rate, and adjust to normal flow rate when the temperature drops below 90℃; B5. After adding hydrogen peroxide, stir for 20 to 40 minutes and then stop stirring to take samples.

[0019] Beneficial effects: (1) Compared with the prior art, the acid leaching solution of this process contains less bismuth and antimony, and the anode mud attached to the anode plate of lead electrolysis after electrolysis does not contain bismuth and antimony, and the adhesion to the residual anode is greatly reduced, which is conducive to natural shedding, reducing the workload of cleaning the anode mud on the residual anode of lead electrolysis. In addition, the lead electrolyte and replenishing solution of the prior art need to be prepared with lead oxide, while the present process directly replenishes with acid leaching solution, eliminating the preparation of replenishing solution with lead oxide, reducing lead oxide pollution in the process of low-grade lead electrolysis. (2) Compared with the prior art, the present process eliminates chlorination refining and does not use chlorine; in the prior art, the anode mud containing high bismuth enters the bismuth refining process and needs to be chlorinated to remove lead. In the present process, the high bismuth slag does not contain lead, so the lead electrolysis anode mud without bismuth no longer enters the bismuth refining, and the lead-free high bismuth slag enters the bismuth refining, eliminating the chlorination refining process, reducing the use of chlorine in the bismuth refining process, and improving the recovery rate of lead and bismuth. At the same time, a small amount of unorganized flue gas containing chlorine is emitted during the chlorine refining process in the prior art, which pollutes the air. After the chlorine refining is cancelled, the amount of chlorine used is reduced, which can not only effectively prevent air pollution, but also the lead loss in the chlorine refining will no longer occur, which can improve the lead recovery rate. In addition, in the prior art, the chlorination refining needs to heat and melt the crude bismuth in the refining electric furnace and pass chlorine to remove the lead. After the chlorine refining is cancelled, the power consumption is reduced. It is energy-saving and emission-reducing, which has certain advantages. DETAILED DESCRIPTION Example

[0020] A wet process for recovering rare and precious metals comprises the following steps: S1. High-temperature melting and refining. Add 599 kg of lead-bismuth alloy into the refining furnace, control the temperature of the lead-bismuth alloy melt at 600°C, and accelerate the melting of the material. After the lead-bismuth alloy material is alloyed, remove the scum on the surface. After removing 124 kg of scum, clean the sticky slag along the refining furnace to obtain the melting alloy melt.

[0021] S2. Alkaline refining of high-temperature melt. The refined melt contains As0.47% and Sb1.47%. The temperature of the melted alloy is controlled at 610℃. The mechanical stirring is hoisted to the refining furnace support. The oxygen tube is inserted 40cm below the surface of the melted alloy and fixed on the stirring support. The oxygen valve is opened, the oxygen amount is adjusted, and the melt is not splashed. The mechanical stirring is started; a bag of caustic soda (25kg) is evenly added into the stirring vortex to check the reaction. When dry slag is generated on the surface of the melt, the arsenic-antimony slag can be fished out. At the beginning of the operation, samples are taken for testing every 5 bags of caustic soda added. At the end of the operation, samples are taken for testing every 2 bags of caustic soda added. According to the content of arsenic, antimony and tin, the whole operation time is about 6h; when the test results show that As is less than 0.01% and Sb is 0.36%, it indicates that the operation has reached the end point. The oxygen valve is closed, the stirring is stopped, and 38kg of arsenic-antimony slag is fished out to obtain the de-arsenicized antimony alloy melt.

[0022] S3. Alloy granulation. Pump the de-arsenicated antimony alloy melt after basic refining into the casting furnace. The casting furnace temperature is controlled at 500℃. Tilt the casting furnace and pour the de-arsenicated antimony alloy melt into the granulator for granulation. During the casting process, the flow rate should be controlled at a uniform speed and not too large to prevent the accumulation of de-arsenicated antimony alloy particles. The cast de-arsenicated antimony alloy particles have no large blocks of adhesion and no other inclusions. The de-arsenicated antimony alloy particles are controlled at 3mm.

[0023] S4. Aqueous solution oxidation acid leaching. Weigh 400kg of arsenic-removed antimony alloy particles, put them into the acid leaching tank, add 1m³ of silicic acid, and start stirring. After stirring for 1 minute, start adding hydrogen peroxide at a rate of 90l / h for 1.5 hours. The reaction is exothermic and the reaction temperature is below 90°C. If the temperature is too high, turn down the hydrogen peroxide valve to reduce the addition rate, and adjust to normal flow rate when the temperature drops below 90°C. After adding hydrogen peroxide, stir for 20 minutes and stop stirring to take samples.

[0024] S5. Filter pressing. After the reaction is completed, the acid leaching liquid in the acid leaching tank is introduced into the middle tank, and then pumped into the filter press for filtration; the filtrate is an acid leaching liquid that does not contain bismuth and antimony, and the filter cake discharged from the filter press is a high-bismuth slag, bismuth enters the high-bismuth slag, and the high-bismuth slag does not contain lead.

[0025] S6. Electrolysis. The acid leaching solution is sent to the lead electrowinning tank or added to the lead electrolyte in the lead-bismuth alloy electrolytic tank. Lead electrowinning or lead-bismuth alloy electrolysis produces cathode lead plates, residual electrodes, and anode mud.

[0026] S7. Casting lead ingots. The cathode lead plates are fed into a lead casting furnace to be melted and cast into lead ingots.

[0027] S8. Chlorine-free bismuth refining. The filter cake discharged from the filter press is high-bismuth slag, which is sent to the bismuth refining process for refining to produce national standard bismuth ingots and silver-zinc shells. The use of chlorine gas is reduced by 59.9kg.

[0028] S9. Gold and silver refining. The silver-zinc shells are sent to the precious metal workshop for refining to produce gold and silver ingots.

[0029] The present invention is a lead-bismuth alloy containing high bismuth, which is refined to remove impurities such as arsenic and antimony, and then granulated. The arsenic-removed antimony alloy particles are 3-6 mm, and then silicic acid or lead silicic acid liquid is added, soaked, and an oxidant (hydrogen peroxide, oxygen, etc.) is passed under stirring. The lead in the arsenic-removed antimony alloy is dissolved in the silicic acid, and the bismuth is also dissolved. However, in the presence of lead, due to the influence of the electrode potential, the bismuth undergoes a substitution reaction and the bismuth is replaced. After the lead is dissolved, some pure lead particles are added to perform substitution and impurity removal treatment, and then solid-liquid separation is performed. The lead silicic acid liquid is sent to electrowinning or used as a replenishing liquid for electrolysis of low-grade lead anode plates to obtain electrolead cast into lead ingots, and the solid bismuth material is sent to bismuth refining to obtain bismuth ingots and silver-zinc shells to achieve the purpose of lead-bismuth separation. Example

[0030] A wet process for recovering rare and precious metals comprises the following steps: S1. High-temperature melting and refining. Add 1110 kg of lead-bismuth alloy into the refining furnace, control the temperature of the lead-bismuth alloy melt at 630°C, and accelerate the melting of the material. After the lead-bismuth alloy material is alloyed, remove the scum on the surface, and after removing 71.6 kg of clean scum, clean the sticky slag along the refining furnace to obtain the melting alloy melt.

[0031] S2. High-temperature melt alkaline refining. When the refined melt contains As0.38% and Sb1.58%, the temperature of the melt is controlled at 615℃, the mechanical stirring is hoisted to the refining furnace support, the oxygen tube is inserted 45cm below the surface of the melt, and fixed on the stirring support, the oxygen valve is opened, the oxygen amount is adjusted, and the melt is not splashed, and the mechanical stirring is started; a bag of caustic soda (25kg) is evenly added into the stirring vortex, and the reaction is checked. When dry slag is generated on the surface of the melt, the arsenic-antimony slag can be fished out. At the beginning of the operation, samples are taken for testing every 5 bags of caustic soda added, and samples are taken for testing every 2 bags of caustic soda added in the later stage of the operation. According to the content of arsenic, antimony and tin, the whole operation time is about 8h; when the test results show that As is less than 0.01% and Sb is 0.27%, it indicates that the operation end point has been reached, the oxygen valve is closed, the stirring is stopped, and 84.3kg of arsenic-antimony slag is fished out to obtain the de-arsenicized antimony alloy melt.

[0032] S3. Alloy granulation. Pump the de-arsenicated antimony alloy melt after basic refining into the casting furnace. The casting furnace temperature is controlled at 525℃. Tilt the casting furnace and pour the de-arsenicated antimony alloy melt into the granulator for granulation. During the casting process, the flow rate should be controlled at a uniform speed and not too large to prevent the accumulation of de-arsenicated antimony alloy particles. The cast de-arsenicated antimony alloy particles have no large blocks of adhesion and no other inclusions. The de-arsenicated antimony alloy particles are controlled at 4mm.

[0033] S4. Aqueous solution oxidation acid leaching. Weigh 697kg of dearsenicated antimony alloy particles, put them into the acid leaching tank, add 1.8m³ of silicic acid, and start stirring. After stirring for 3 minutes, start adding oxygen at a rate of 110l / h for 2 hours. The reaction is exothermic and the reaction temperature is below 90°C. If the temperature is too high, turn down the hydrogen peroxide valve to reduce the addition rate, and adjust to normal flow when the temperature drops below 90°C. After adding hydrogen peroxide, stir for 30 minutes and stop stirring to take samples.

[0034] S5. Filter pressing. After the reaction is completed, the acid leaching liquid in the acid leaching tank is introduced into the middle tank, and then pumped into the filter press for filtration.

[0035] S6. Electrolysis. The acid leaching solution is sent to the lead electrowinning tank or added to the lead electrolyte in the lead-bismuth alloy electrolytic tank. Lead electrowinning or lead-bismuth alloy electrolysis produces cathode lead plates, residual electrodes, and anode mud.

[0036] S7. The cathode lead plate is fed into a lead casting furnace for melting and then cast into lead ingots.

[0037] S8. Chlorine-free bismuth refining. The filter cake discharged from the filter press is high-bismuth slag, which is sent to the bismuth refining process for refining to produce national standard bismuth ingots and silver-zinc shells. Chlorine refining is cancelled, reducing the use of chlorine by 111kg.

[0038] S8. Gold and silver refining. The silver-zinc shells are sent to the precious metal workshop for refining to produce gold and silver ingots. Example

[0039] A wet process for recovering rare and precious metals comprises the following steps: S1. High-temperature melting and refining. Add 913kg of lead-bismuth alloy into the refining furnace, control the temperature of the lead-bismuth alloy melt at 650℃, and accelerate the melting of the material. After the lead-bismuth alloy material is alloyed, remove the scum on the surface, and after removing 9.5kg of clean scum, clean the sticky slag along the refining furnace to obtain the melting alloy melt.

[0040] S2. High-temperature melt alkaline refining. When the refined melt contains As0.41% and Sb1.57%, the temperature of the molten alloy is controlled at 620℃, the mechanical stirring is hoisted to the refining furnace support, the oxygen tube is inserted 50cm below the surface of the lead-bismuth alloy melt, and fixed on the stirring support, the oxygen valve is opened, the oxygen amount is adjusted, and the melt is not splashed, and the mechanical stirring is started; a bag of caustic soda (25kg) is evenly added into the stirring vortex, and the reaction is checked. When dry slag is generated on the surface of the melt, the arsenic-antimony slag can be fished out. At the beginning of the operation, samples are taken for testing every 5 bags of caustic soda added, and samples are taken for testing every 2 bags of caustic soda added in the later stage of the operation. According to the content of arsenic, antimony and tin, the whole operation time is about 10h; the test results show that As is less than 0.01% and Sb is 0.22%, indicating that the operation end point has been reached, the oxygen valve is closed, the stirring is stopped, and 50kg of arsenic-antimony slag is fished out to obtain the de-arsenicized antimony alloy melt.

[0041] S3. Alloy granulation. Pump the de-arsenicated antimony alloy melt after basic refining into the casting furnace. The casting furnace temperature is controlled at 550°C. Tilt the casting furnace and pour the de-arsenicated antimony alloy melt into the granulator for granulation. During the casting process, the flow rate should be controlled at a uniform speed and not too large to prevent the accumulation of de-arsenicated antimony alloy particles. The cast de-arsenicated antimony alloy particles have no large blocks of adhesion and no other inclusions. The de-arsenicated antimony alloy particles are controlled at 6mm.

[0042] S4. Aqueous solution oxidation acid leaching. Weigh 767kg of arsenic-removed antimony alloy particles, put them into the acid leaching tank, add 2m³ of silicic acid, and start stirring. After stirring for 5 minutes, start adding hydrogen peroxide at a rate of 120l / h for 2.5 hours. The reaction is exothermic, and the reaction temperature is below 90°C. If the temperature is too high, turn down the hydrogen peroxide valve to reduce the addition rate, and adjust to normal flow when the temperature drops below 90°C. After adding hydrogen peroxide, stir for 40 minutes and stop stirring to take samples.

[0043] S5. Filter pressing. After the reaction is completed, the acid leaching liquid in the acid leaching tank is introduced into the middle tank, and then pumped into the filter press for filtration.

[0044] S6. Electrolysis. The acid leaching solution is sent to the lead electrowinning tank or added to the lead electrolyte in the lead-bismuth alloy electrolytic tank. Lead electrowinning or lead-bismuth alloy electrolysis produces cathode lead plates, residual electrodes, and anode mud. S7. Casting lead ingots. The cathode lead plates are sent into the lead casting furnace for melting and then cast into lead ingots.

[0045] S8. Chlorine-free bismuth refining. The filter cake discharged from the filter press is high-bismuth slag, which is sent to the bismuth refining process for refining to produce national standard bismuth ingots and silver-zinc shells. Chlorine refining is cancelled, reducing the use of chlorine by 76.7kg.

[0046] S9. Gold and silver refining. The silver-zinc shells are sent to the precious metal workshop for refining to produce gold and silver ingots.

[0047] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0048] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A wet process for recovering rare and precious metals, characterized in that: The following steps are involved: S1. Melting refining: adding the lead-bismuth alloy into a refining furnace to melt, and after the melting is completed, removing the slag on the surface of the melt; S2. Alkaline refining of the melt: When the total amount of arsenic and antimony in the melt is greater than 1%, alkaline refining is performed to remove arsenic, antimony and tin to obtain a de-arsenicized antimony alloy melt; when the antimony content in the melt is less than 6‰, the alloy granulation process is directly performed; S3 alloy granulation: the melt after step S2 is pumped into a casting furnace, the casting furnace is tilted, the melt is introduced into a granulator for granulation, and arsenic-free antimony alloy particles are obtained; S4. Aqueous solution oxidation acid leaching: the dearsenicated antimony alloy particles are placed in an acid leaching tank, stirred with a silicic acid solution, and then an oxidant is added; S5. Filtration: After the reaction is completed, the acid leaching liquid in the acid leaching tank is introduced into the intermediate tank, and then pumped into the filter press for filtration; S6. Lead electrolysis: sending the acid leaching solution to the lead electrowinning cell or adding it to the lead-bismuth alloy electrolytic cell, and producing cathode lead plates, residual electrodes and anode mud by lead electrowinning or lead-bismuth alloy electrolysis; S7. Casting lead ingots: feeding the cathode lead plate into a lead casting furnace to melt and cast into lead ingots; S8. Chlorine-free bismuth refining: The filter cake discharged from the filter press is high-bismuth slag, which is sent to the bismuth refining process for refining to produce national standard bismuth ingots and silver-zinc shells; S9. Gold and silver refining: send the silver-zinc shells to the precious metal workshop for refining to produce national standard gold and silver ingots.

2. A wet process for recovering rare and precious metals according to claim 1, characterized in that: The operating temperature of the smelting refining in the step S1 is 600-650°C.

3. A wet process for recovering rare and precious metals according to claim 1, characterized in that: The steps of the basic refining operation for removing arsenic, antimony and tin in the S2 step are as follows: A1. Control the temperature of the alloy melt obtained by S1 to be between 610 and 620°C; A2. Insert the oxygen tube 40-50 cm below the surface of the molten alloy and start mechanical stirring; A3. Add alkali into the stirring vortex, and remove the arsenic antimony slag when dry slag is formed on the surface of the melt; A4. Depending on the content of arsenic, antimony and tin, the entire operation time is about 6 to 10 hours; A5. When arsenic is less than 0.01% and antimony is less than 0.6%, it indicates that the operation has reached the end point. Close the oxygen valve, stop stirring, and remove the arsenic and antimony slag.

4. A wet process for recovering rare and precious metals according to claim 1, characterized in that: In the step S3, the operating temperature of the casting furnace is controlled at 500-550°C.

5. A wet process for recovering rare and precious metals according to claim 1, characterized in that: In the step S3, the size of the dearsenicized antimony alloy particles is controlled to be 3-6 mm.

6. A wet process for recovering rare and precious metals according to claim 1, characterized in that: The steps of aqueous solution oxidation acid leaching operation in step S4 are: B1. Loading the dearsenicated antimony alloy particles into the acid leaching tank; B2. Add silicic acid and start stirring; B3. After stirring for 1 to 5 minutes, start adding the oxidant at a rate of 90 to 120 l / h for 1.5 to 2.5 hours; B4. The reaction temperature is below 80-95℃. If the temperature is too high, close the hydrogen peroxide valve to reduce the addition rate, and adjust to normal flow rate when the temperature drops below 90℃; B5. After adding the oxidant, stir for 20 to 40 minutes and then stop stirring to take samples.