Method for recycling valuable metal by using precious metal waste catalyst, lead-zinc slag and waste cathode carbon

Abstract

The invention discloses a method for recycling valuable metals by using a precious metal waste catalyst, lead-zinc slag and waste cathode carbon, and belongs to the technical field of metal resource recycling. The method comprises the following steps: grinding and screening a waste noble metal catalyst, lead-zinc slag and waste cathode carbon, uniformly mixing with a fluxing agent, carrying out reduction smelting, reducing Fe < 3 > O < 4 >, Fe2SiO4 and other iron-containing compounds in the process to generate a metal simple substance, capturing noble metals (platinum, palladium, rhodium and silver) to form a Fe-based alloy, and cooling the molten slag at a high temperature to prepare the environment-friendly aluminosilicate microcrystalline glass. According to the method, CaO-SiO2-Al2O3-MgO-Na2O in the mixed slag is used as a slag system, a fluxing agent is CaO, Na2O, SiO2 and Na2B4O7. 10H2O, the waste cathode carbon is used as a reducing agent to recover valuable metals, and the recovery rates of platinum, palladium, rhodium, silver, iron and zinc are up to 99.72%, 98.17%, 98.27%, 99.87%, 98.65% and 99.99% respectively. According to the method, the precious metal waste catalyst, the lead-zinc slag and the waste cathode carbon are comprehensively utilized, and the method has great significance in green and efficient recovery of valuable metal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal resource recycling, in particular to a method for recycling valuable metals from precious metal waste catalysts, lead-zinc slag and waste cathode carbon. BACKGROUND

[0002] Precious metal waste catalysts are classified as hazardous waste, and their components include platinum group metals platinum, palladium, rhodium and matrix (Al2O3, SiO2 and MgO). Although platinum group metals have high economic value, their recovery processes involve multiple fine steps and are relatively complex. Currently, platinum group metals can be recovered by hydrometallurgy and pyrometallurgy. The hydrometallurgical recovery process produces nitrogen oxides and HCN gas, has low recovery rate and generates a large amount of wastewater. The pyrometallurgical recovery process requires a large amount of iron powder, fluxing agent and reducing agent, and has problems such as high economic cost and difficult recovery, which have long restricted its efficient and economical industrial application.

[0003] Lead-zinc slag contains high iron (>29wt.%) and other valuable metals (zinc, silver, etc.). Lead-zinc slag is mainly derived from waste slag treated by a fuming furnace during lead smelting and zinc leaching process, and contains a large amount of SiO2, CaO and other components. The large amount of lead-zinc slag cannot be directly utilized, and the iron in the lead-zinc slag mainly exists in the form of oxide. Because the economic value of recovering metallic iron by reducing with anthracite alone is low, and due to the high impurity content, the lead-zinc slag cannot be directly used as ironmaking raw material. Zinc and silver cannot be recovered, and the toxic heavy metal elements in the fuming slag have brought great pressure to the environment.

[0004] Waste cathode carbon contains amorphous carbon / graphitized carbon (content about 50%~70%), soluble fluoride, high-melting-point Al2O3 phase and cyanide. Waste cathode carbon is the main hazardous solid waste generated by the aluminum electrolysis industry. Although waste cathode carbon contains a large amount of carbon, it cannot be economically and efficiently utilized due to its complex composition and the presence of toxic fluorine.

[0005] How to harmlessly, efficiently and economically utilize precious metal waste catalysts, lead-zinc slag and waste cathode carbon has become a problem to be solved. SUMMARY

[0006] To solve the problem of harmlessly, efficiently and economically utilizing precious metal waste catalysts, lead-zinc slag and waste cathode carbon, the present application provides a method for recycling valuable metals from precious metal waste catalysts, lead-zinc slag and waste cathode carbon. The method utilizes precious metal waste catalysts, lead-zinc slag and waste cathode carbon to comprehensively recover valuable metals.

[0007] The method for recycling valuable metals from precious metal waste catalysts, lead-zinc slag and waste cathode carbon according to the present application specifically comprises the following steps: (1) grinding, sieving the noble metal waste catalyst, lead-zinc slag and waste cathode carbon respectively to obtain noble metal waste catalyst powder, lead-zinc slag powder and waste cathode carbon powder.

[0008] (2) uniformly mixing the noble metal waste catalyst powder, lead-zinc slag powder, waste cathode carbon powder and flux to obtain mixed powder.

[0009] (3) reducing smelting the mixed powder under inert gas condition, in the process of reducing smelting, the iron-containing compound is reduced to generate elemental iron and captures platinum, palladium, rhodium and silver to form Fe-based alloy, at the same time, Zn volatilization is recovered to obtain elemental zinc through condensation.

[0010] (4) after the smelting slag is cooled, physical separation is carried out to obtain glass-ceramic slag and Fe-based alloy.

[0011] Preferably, the noble metal waste catalyst in step (1) of the present application is waste ternary automobile catalyst or waste platinum-palladium leaching residue.

[0012] Preferably, the particle size of the noble metal waste catalyst powder, lead-zinc slag powder and waste cathode carbon powder in step (1) of the present application is 50-200 mesh.

[0013] Preferably, the mass ratio of the noble metal waste catalyst powder, lead-zinc slag powder and waste cathode carbon powder in step (2) of the present application is 1:(0.1-1.5):(0.01-0.3).

[0014] Preferably, the flux in step (2) of the present application is a mixture composed of CaO, Na2O, SiO2 and Na2B4O7·10H2O; by adjusting the addition mass of Al2O3, CaO, Na2O, SiO2 and Na2B4O7·10H2O, the basicity range of the slag system is controlled to be 0.5-1.2, wherein the mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:2-3:0.5-6, and the basicity is calculated by (CaO+Na2O) / (Al2O3+B2O3+SiO2).

[0015] Preferably, the inert gas in step (3) of the present application is nitrogen or argon, more preferably nitrogen, and the gas flow is 50-300 mL / min.

[0016] Preferably, the reducing smelting condition in step (3) of the present application is that the reducing smelting is carried out at a temperature of 1350-1500℃ for 30-180 min.

[0017] Compared with the prior art, the present application provides a method for recovering valuable metals by using noble metal waste catalyst, lead-zinc slag and waste cathode carbon, which has the following beneficial effects: (1) This invention achieves the maximum utilization of resources by comprehensively recovering valuable metals through the synergistic treatment of precious metal waste catalyst, lead-zinc slag and waste cathode carbon. The waste cathode carbon is used as a reducing agent to reduce Fe in lead-zinc slag and capture platinum, palladium, rhodium and silver. This can reduce the amount of iron capture agent (iron powder) and anthracite coal added as a reducing agent in traditional processes. At the same time, lead-zinc slag and waste cathode carbon provide some fluxing agents CaO, SiO2 and Na2O, reducing the amount of flux used. This achieves the efficient reuse of three kinds of solid hazardous waste, greatly reduces the pollution to the environment, and has high economic and environmental benefits.

[0018] (2) The present invention adjusts the alkalinity of the slag system to the range of 0.5 to 1.2, which can ensure that the slag has a low melting point and good fluidity, which is conducive to the collision and capture of precious metals and iron, while reducing energy consumption; in addition, the chemical composition of the slag directly determines whether a stable and dense microcrystalline glass can be formed after cooling, thereby realizing the harmless and resource utilization of waste.

[0019] (3) The present invention achieves high recovery rates of 99.72%, 98.17%, 98.27%, 99.87%, 98.65% and 99.99% for platinum, palladium, rhodium, silver, iron and zinc, respectively, realizing efficient recovery of valuable metals.

[0020] (4) The microcrystalline glass prepared by this invention belongs to the environmentally friendly aluminosilicate system microcrystalline glass. The toxicity leaching test results show that its leaching residue can be regarded as a harmless substance, and the relevant data meet the requirements of US-EPA standards, and can be safely applied in the ceramics and construction fields. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of the present invention.

[0022] Figure 2 This is the XRD pattern of the microcrystalline glass obtained in Example 7.

[0023] Figure 3 This is a bar chart showing the toxicity leaching results of the microcrystalline glass prepared in Example 7. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the embodiments and comparative examples of this invention, a mixture of CaO, Na2O, SiO2 and Na2B4O7·10H2O was used as a flux to optimize the slag type. The basicity of the slag system was controlled by adjusting the addition mass of Al2O3, CaO, Na2O, SiO2 and Na2B4O7·10H2O. The basicity was calculated by (CaO+Na2O) / (Al2O3+B2O3+SiO2).

[0026] Example 1 This embodiment utilizes waste three-way automotive catalysts, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) The waste three-way automotive catalyst, lead-zinc slag and waste cathode carbon were ground and sieved to obtain waste three-way automotive catalyst powder (particle size of 200 mesh), lead-zinc slag powder (particle size of 200 mesh) and waste cathode carbon powder (particle size of 200 mesh).

[0027] (2) The waste three-way automotive catalyst powder, lead-zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead-zinc slag powder and waste cathode carbon powder is 1:1:0.15. The amount of flux added is based on the alkalinity, which is 1.15. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:2.

[0028] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 200 mL / min and reduced at 1400 °C for 60 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0029] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0030] Calculations show that the recoveries of platinum, palladium, rhodium, silver, iron, and zinc in this embodiment are 98.08%, 99.18%, 98.29%, 98.15%, 90.03%, and 98.58%, respectively.

[0031] Example 2 This embodiment utilizes waste three-way automotive catalysts, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) The waste three-way automotive catalyst, lead-zinc slag and waste cathode carbon were ground and sieved to obtain waste three-way automotive catalyst powder (particle size of 200 mesh), lead-zinc slag powder (particle size of 200 mesh) and waste cathode carbon powder (particle size of 200 mesh).

[0032] (2) The waste three-way automotive catalyst powder, lead-zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead-zinc slag powder and waste cathode carbon powder is 1:1:0.25. The amount of flux added is based on the alkalinity, which is 0.95. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:4.

[0033] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 300 mL / min and reduced at 1400℃ for 150 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0034] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0035] Calculations show that the recoveries of platinum, palladium, rhodium, silver, iron, and zinc in this embodiment are 98.50%, 99.09%, 98.11%, 95.10%, 83.26%, and 98.32%, respectively.

[0036] Example 3 This embodiment utilizes waste three-way automotive catalysts, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) The waste three-way automotive catalyst, lead-zinc slag and waste cathode carbon were ground and sieved to obtain waste three-way automotive catalyst powder (particle size of 200 mesh), lead-zinc slag powder (particle size of 200 mesh) and waste cathode carbon powder (particle size of 200 mesh).

[0037] (2) The waste three-way automotive catalyst powder, lead-zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead-zinc slag powder and waste cathode carbon powder is 1:1:0.01. The amount of flux added is based on the alkalinity, which is 0.95. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:0.5.

[0038] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 100 mL / min and reduced at 1400℃ for 150 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0039] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0040] Calculations show that the recoveries of platinum, palladium, rhodium, silver, iron, and zinc in this embodiment are 80.15%, 83.88%, 77.79%, 78.25%, 81.78%, and 85.20%, respectively.

[0041] Example 4 This embodiment utilizes waste three-way automotive catalysts, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) The waste three-way automotive catalyst, lead-zinc slag and waste cathode carbon were ground and sieved to obtain waste three-way automotive catalyst powder (particle size of 200 mesh), lead-zinc slag powder (particle size of 200 mesh) and waste cathode carbon powder (particle size of 200 mesh).

[0042] (2) The waste three-way automotive catalyst powder, lead-zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead-zinc slag powder and waste cathode carbon powder is 1:1:0.15. The amount of flux added is based on the alkalinity, which is 0.95. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:2.

[0043] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 80 mL / min and reduced at 1350℃ for 150 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0044] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0045] Calculations show that the recoveries of platinum, palladium, rhodium, silver, iron, and zinc in this embodiment are 85.20%, 88.48%, 87.46%, 85.20%, 82.88%, and 87.56%, respectively.

[0046] Example 5 This embodiment utilizes waste three-way automotive catalysts, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) The waste three-way automotive catalyst, lead-zinc slag and waste cathode carbon were ground and sieved to obtain waste three-way automotive catalyst powder (particle size of 200 mesh), lead-zinc slag powder (particle size of 200 mesh) and waste cathode carbon powder (particle size of 200 mesh).

[0047] (2) The waste three-way automotive catalyst powder, lead-zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead-zinc slag powder and waste cathode carbon powder is 1:1:0.15. The amount of flux added is based on the alkalinity, which is 0.95. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:6.

[0048] (3) The mixed powder is placed under a nitrogen atmosphere with a gas flow rate of 100 mL / min and reduced at 1500℃ for 150 min. During the reduction smelting process, the iron-containing compounds are reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver are captured to form Fe-based alloys. At the same time, the Zn volatiles are recovered by condensation to obtain elemental zinc.

[0049] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0050] Calculations show that the recoveries of platinum, palladium, rhodium, silver, iron, and zinc in this embodiment are 95.25%, 98.99%, 99.04%, 95.20%, 96.15%, and 96.56%, respectively. Example 6 This embodiment utilizes waste three-way automotive catalysts, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) The waste three-way automotive catalyst, lead-zinc slag and waste cathode carbon were ground and sieved to obtain waste three-way automotive catalyst powder (particle size of 100 mesh), lead-zinc slag powder (particle size of 100 mesh) and waste cathode carbon powder (particle size of 100 mesh).

[0051] (2) The waste three-way automotive catalyst powder, lead-zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead-zinc slag powder and waste cathode carbon powder is 1:0.6:0.09. The amount of flux added is based on the alkalinity, which is 0.95. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:1.5.

[0052] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 100 mL / min and reduced at 1400℃ for 150 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0053] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0054] Calculations show that the recoveries of platinum, palladium, rhodium, silver, iron, and zinc in this embodiment are 87.52%, 85.65%, 86.12%, 85.20%, 85.29%, and 89.14%, respectively.

[0055] Example 7 This embodiment utilizes waste three-way automotive catalysts, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) The waste three-way automotive catalyst, lead-zinc slag and waste cathode carbon were ground and sieved to obtain waste three-way automotive catalyst powder (particle size of 200 mesh), lead-zinc slag powder (particle size of 200 mesh) and waste cathode carbon powder (particle size of 200 mesh).

[0056] (2) The waste three-way automotive catalyst powder, lead-zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead-zinc slag powder and waste cathode carbon powder is 1:0.8:0.12. The amount of flux added is based on the alkalinity, which is 0.95. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:5.

[0057] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 100 mL / min and reduced at 1400℃ for 150 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0058] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0059] Calculations show that the recoveries of platinum, palladium, rhodium, silver, iron, and zinc in this embodiment are 99.72%, 98.17%, 98.27%, 99.87%, 98.65%, and 99.99%, respectively.

[0060] The XRD pattern of the microcrystalline glass phase analysis prepared in this embodiment is shown in the figure. Figure 2 As shown in the spectrum, there is a clear presence of Na. 1.45 Al 1.45 Si 0.55 The presence of characteristic diffraction peaks for O4 and Ca2Al2SiO7, along with the good crystallinity of these two phases, indicates that Na has been successfully precipitated in the aluminosilicate-based glass-ceramic. 1.45 Al 1.45 Si 0.55 The presence of two crystalline phases, O4 and Ca2Al2SiO7, confirms that the material is an aluminosilicate-based microcrystalline glass.

[0061] The microcrystalline glass prepared in this embodiment was subjected to a toxicity leaching test, such as...Figure 3 As shown, the Cr, Pb, Zn, Ni, and Cu elements in this microcrystalline glass all meet the US-EPA standards, and this microcrystalline glass can be considered a harmless material.

[0062] Example 8 This embodiment utilizes waste platinum-palladium leaching residue, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) Grind and sieve the waste platinum palladium leaching residue, lead zinc slag and waste cathode carbon respectively to obtain waste platinum palladium leaching residue powder (particle size 50 mesh), lead zinc slag powder (particle size 100 mesh) and waste cathode carbon powder (particle size 100 mesh).

[0063] (2) The waste platinum palladium leaching residue powder, lead zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead zinc slag powder and waste cathode carbon powder is 1:1:0.2. The amount of flux added is based on the basicity, which is 1.2. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:4.

[0064] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 300 mL / min and reduced at 1400℃ for 90 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0065] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0066] Calculations show that the recoveries of platinum, palladium, silver, iron, and zinc in this embodiment are 98.04%, 94.82%, 90.82%, 82.95%, and 99.84%, respectively.

[0067] Example 9 This embodiment utilizes waste platinum-palladium leaching residue, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) The waste platinum palladium leaching residue, lead zinc slag and waste cathode carbon are ground and sieved to obtain waste platinum palladium leaching residue powder (particle size of 200 mesh), lead zinc slag powder (particle size of 100 mesh) and waste cathode carbon powder (particle size of 100 mesh).

[0068] (2) The waste platinum palladium leaching residue powder, lead zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead zinc slag powder and waste cathode carbon powder is 1:1:0.3. The amount of flux added is based on the alkalinity, which is 0.9. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:4.5.

[0069] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 100 mL / min and reduced at 1400℃ for 150 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0070] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0071] Calculations show that the recoveries of platinum, palladium, silver, iron, and zinc in this embodiment are 98.72%, 96.25%, 96.49%, 93.64%, and 99.86%, respectively.

[0072] Example 10 This embodiment utilizes waste platinum-palladium leaching residue, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) The waste platinum palladium leaching residue, lead zinc slag and waste cathode carbon are ground and sieved to obtain waste platinum palladium leaching residue powder (particle size of 200 mesh), lead zinc slag powder (particle size of 200 mesh) and waste cathode carbon powder (particle size of 200 mesh).

[0073] (2) The waste platinum palladium leaching residue powder, lead zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead zinc slag powder and waste cathode carbon powder is 1:1:0.14. The amount of flux added is based on the basicity, which is 0.9. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:2.

[0074] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 300 mL / min and reduced at 1400℃ for 100 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0075] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0076] Calculations show that the recoveries of platinum, palladium, silver, iron, and zinc in this embodiment are 91.54%, 87.46%, 85.92%, 87.64%, and 88.72%, respectively.

[0077] Example 11 This embodiment utilizes waste platinum-palladium leaching residue, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) The waste platinum palladium leaching residue, lead zinc slag and waste cathode carbon are ground and sieved to obtain waste platinum palladium leaching residue powder (particle size of 200 mesh), lead zinc slag powder (particle size of 200 mesh) and waste cathode carbon powder (particle size of 200 mesh).

[0078] (2) The waste platinum palladium leaching residue powder, lead zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead zinc slag powder and waste cathode carbon powder is 1:1:0.2. The amount of flux added is based on the basicity, which is 0.5. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:2.

[0079] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 300 mL / min and reduced at 1450℃ for 120 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0080] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0081] Calculations show that the recoveries of platinum, palladium, silver, iron, and zinc in this embodiment are 90.72%, 90.17%, 90.87%, 90.65%, and 91.99%, respectively.

[0082] Example 12 This embodiment utilizes waste platinum-palladium leaching residue, lead-zinc slag, and waste cathode carbon to recover valuable metals. Specific steps include: (1) The waste platinum palladium leaching residue, lead zinc slag and waste cathode carbon are ground and sieved to obtain waste platinum palladium leaching residue powder (particle size of 200 mesh), lead zinc slag powder (particle size of 200 mesh) and waste cathode carbon powder (particle size of 200 mesh).

[0083] (2) The waste platinum palladium leaching residue powder, lead zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead zinc slag powder and waste cathode carbon powder is 1:0.5:0.1. The amount of flux added is based on the alkalinity, which is 0.9. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:3.

[0084] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 300 mL / min and reduced at 1400℃ for 120 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0085] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0086] Calculations show that the recoveries of platinum, palladium, silver, iron, and zinc in this embodiment are 98.72%, 98.07%, 96.87%, 79.98%, and 99.87%, respectively.

[0087] Comparative Example 1 This comparative example utilizes waste three-way automotive catalysts, lead-zinc slag, and waste cathode carbon to recover valuable metals. The specific steps include: (1) The waste three-way automotive catalyst, lead-zinc slag and waste cathode carbon were ground and sieved to obtain waste three-way automotive catalyst powder (particle size of 200 mesh), lead-zinc slag powder (particle size of 200 mesh) and waste cathode carbon powder (particle size of 200 mesh).

[0088] (2) The waste three-way automotive catalyst powder, lead-zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead-zinc slag powder and waste cathode carbon powder is 1:1:0.15. The amount of flux added is based on the alkalinity, which is 0.75. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:0.2.

[0089] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 50 mL / min and reduced at 1300℃ for 30 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0090] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0091] The recoveries of platinum, palladium, rhodium, silver, iron, and zinc in this comparative example were calculated to be 58.52%, 66.25%, 72.09%, 44.18%, and 55.80%, respectively.

[0092] Comparative Example 2 This comparative example utilizes waste platinum-palladium leaching residue, lead-zinc slag, and waste cathode carbon to recover valuable metals. The specific steps include: (1) Grind and sieve the waste platinum palladium leaching residue, lead zinc slag and waste cathode carbon respectively to obtain waste platinum palladium leaching residue powder (particle size 50 mesh), lead zinc slag powder (particle size 100 mesh) and waste cathode carbon powder (particle size 100 mesh).

[0093] (2) The waste platinum palladium leaching residue powder, lead zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead zinc slag powder and waste cathode carbon powder is 1:1:0.2. The amount of flux added is based on the basicity, which is 0.40. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:0.1.

[0094] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 300 mL / min and reduced at 140 °C for 60 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0095] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0096] The recoveries of platinum, palladium, silver, iron, and zinc in this comparative example were calculated to be 78.39%, 78.75%, 46.28%, 52.59%, and 84.40%, respectively.

[0097] Comparative Example 3 This comparative example utilizes waste platinum-palladium leaching residue, lead-zinc slag, and waste cathode carbon to recover valuable metals. The specific steps include: (1) Grind and sieve the waste platinum palladium leaching residue, lead zinc slag and waste cathode carbon respectively to obtain waste platinum palladium leaching residue powder (particle size 100 mesh), lead zinc slag powder (particle size 100 mesh) and waste cathode carbon powder (particle size 100 mesh).

[0098] (2) The waste platinum palladium leaching residue powder, lead zinc slag powder, waste cathode carbon powder and flux are uniformly mixed to obtain a mixed powder. The mass ratio of the waste metal catalyst powder, lead zinc slag powder and waste cathode carbon powder is 1:1:0.004. The amount of flux added is based on the alkalinity, which is 0.5. The mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:3:0.3.

[0099] (3) The mixed powder was placed under a nitrogen atmosphere with a gas flow rate of 100 mL / min and reduced at 1300℃ for 60 min. During the reduction smelting process, the iron-containing compounds were reduced to generate metallic elemental iron and platinum, palladium, rhodium and silver were captured to form Fe-based alloys. At the same time, the Zn volatiles were recovered by condensation to obtain elemental zinc.

[0100] (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

[0101] The recoveries of platinum, palladium, silver, iron, and zinc in this comparative example were calculated to be 37.12%, 21.93%, 6.87%, 18.53%, and 5.17%, respectively.

[0102] As can be seen from the recovery rates of Comparative Examples 1 to 3, low temperature, low alkalinity, and a small amount of borax all lead to an increase in the viscosity of the slag, which hinders the contact between precious metals and iron particles. In addition, a small amount of reducing agent cannot reduce the iron oxides in the lead-zinc slag, thus failing to achieve the capture of precious metals by iron.

[0103] In summary, this invention achieves maximum resource utilization by synergistically treating precious metal waste catalysts, lead-zinc slag, and waste cathode carbon to comprehensively recover valuable metals. The waste cathode carbon is used to reduce Fe in the lead-zinc slag, capturing precious metals such as platinum, palladium, rhodium, and silver. Zinc is recovered through volatilization. This reduces the amount of iron trapping agent (iron powder) and anthracite reducing agent required in traditional processes. Simultaneously, the lead-zinc slag and waste cathode carbon provide some fluxing agents CaO, SiO2, and Na2O, reducing the amount of flux used. After cooling, the smelting slag can be separated into microcrystalline glass slag and Fe-based alloys. The microcrystalline glass slag can be considered a harmless substance and can be safely applied in the ceramics and construction fields. This invention achieves efficient reuse of three types of solid hazardous waste, greatly reducing environmental pollution and demonstrating high economic and environmental benefits.

[0104] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for recovering valuable metals from spent precious metal catalysts, lead-zinc slag, and spent cathode carbon, characterized in that, Includes the following steps: (1) The precious metal waste catalyst, lead-zinc slag and waste cathode carbon are ground and sieved respectively to obtain precious metal waste catalyst powder, lead-zinc slag powder and waste cathode carbon powder. (2) Mix the precious metal waste catalyst powder, lead-zinc slag powder, waste cathode carbon powder and flux evenly to obtain a mixed powder; (3) The mixed powder is subjected to reduction smelting under inert gas conditions. During the reduction smelting process, the iron-containing compounds are reduced to generate metallic elemental iron, and platinum, palladium, rhodium and silver are captured to form Fe-based alloys. At the same time, the Zn volatiles are recovered by condensation to obtain elemental zinc. (4) After the smelting slag is cooled, it is physically separated to obtain microcrystalline glass slag and Fe-based alloy.

2. The method for recovering valuable metals from spent precious metal catalysts, lead-zinc slag, and spent cathode carbon according to claim 1, characterized in that, The precious metal waste catalyst mentioned in step (1) is waste ternary automotive catalyst or waste platinum-palladium leaching residue.

3. The method for recovering valuable metals from spent precious metal catalysts, lead-zinc slag, and spent cathode carbon according to claim 1, characterized in that, The particle size of the precious metal waste catalyst powder, lead-zinc slag powder and waste cathode carbon powder mentioned in step (1) is 50~200 mesh.

4. The method for recovering valuable metals from spent precious metal catalysts, lead-zinc slag, and spent cathode carbon according to claim 1, characterized in that, In step (2), the mass ratio of precious metal waste catalyst powder, lead-zinc slag powder and waste cathode carbon powder is 1:(0.1~1.5):(0.01~0.3).

5. The method for recovering valuable metals from spent precious metal catalysts, lead-zinc slag, and spent cathode carbon according to claim 1, characterized in that, The flux mentioned in step (2) is a mixture of CaO, Na2O, SiO2 and Na2B4O7·10H2O; by adjusting the addition mass of Al2O3, CaO, Na2O, SiO2 and Na2B4O7·10H2O, the basicity range of the slag system is controlled to be 0.5~1.2, wherein the mass ratio of Na2O, CaO and Na2B4O7·10H2O is 1:2~3:0.5~6.

6. The method for recovering valuable metals from spent precious metal catalysts, lead-zinc slag, and spent cathode carbon according to claim 1, characterized in that, In step (3), the inert gas is nitrogen or argon, and the gas flow rate is 50~300mL / min.

7. The method for recovering valuable metals from spent precious metal catalysts, lead-zinc slag, and spent cathode carbon according to claim 1, characterized in that, The conditions for reduction melting in step (3) are: reduction melting at a temperature of 1350~1500℃ for 30~180min.

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