Method for recovering platinum group metal through collaborative smelting of waste automobile catalyst and electric furnace dust

Abstract

The invention relates to the technical field of metallurgical engineering, and particularly provides a method for recovering platinum group metal through collaborative smelting of a waste automobile catalyst and electric furnace dust, which comprises the following steps: (1) uniformly mixing the waste automobile catalyst, the electric furnace dust, a carbon reducing agent and a slag former to obtain a mixture, with the mass ratio of the waste automobile catalyst to the electric furnace dust being (60-80): (40-20); (2) roasting the mixture obtained in the step (1) to remove volatile components and moisture in the raw materials; and (3) smelting and trapping the roasted product obtained in the step (2) at high temperature to obtain glassy slag and iron alloy containing platinum group metal. According to the method, recycling of valuable metal such as platinum group metal is achieved through carbon thermal-melting coupling reduction, the two dangerous / solid wastes of the waste automobile catalyst and the electric furnace dust can be treated at the same time, the using amount of an additional slag former and an iron trapping agent is reduced, the technological process is short, the platinum group metal recycling rate is high, and cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgical engineering, and in particular to a method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust. Background Art

[0002] Platinum group metals have excellent physical and chemical properties such as corrosion resistance, high temperature resistance and good catalytic activity, and are widely used in electronic products, automobiles, aerospace, and chemical industries. Platinum group metal secondary resources represented by automobile waste catalysts contain a large amount of high-grade platinum group metals. Therefore, research on the recycling of waste automobile catalysts and improving the recovery rate of platinum group metals are of great significance to the sustainable development of platinum group metals.

[0003] Due to the unique purification ability of platinum group metals on automobile exhaust, it can greatly reduce the environmental pollution caused by automobile exhaust. Every year, more than 60% of platinum, palladium and rhodium are used to produce automobile exhaust purification catalysts. Although the waste automobile catalyst has lost its catalytic ability, the platinum group metals inside it have not been lost, so it has great recycling value.

[0004] At present, there are two main methods for recovering platinum group metals from waste automobile catalysts: wet method and pyrometallurgy. Among them, the wet process for recovering platinum group metals will produce waste water and waste residue, and the recovery rate is low. The pyrometallurgy technology adds metal scavengers to waste automobile catalysts for high-temperature treatment, so that most of the platinum group metals in the catalyst are separated from the carrier, thereby obtaining an enriched product with a high content of platinum group metals. Compared with the wet process, it has the advantages of less waste water and waste residue, strong raw material adaptability, and high recovery rate of platinum group metals. It is widely used in the field of platinum group metal recovery. However, the traditional pyrometallurgical smelting and capture process has problems such as large amount of reagents added and few types of hazardous wastes treated at a time. In addition, the existing iron, copper, and nickel capture will cause heavy metal pollution. In order to achieve high-temperature smelting, a large amount of energy is consumed, resulting in increased production costs. These problems seriously restrict the green and sustainable development of platinum group metal recovery. Therefore, there is a need for a method for recovering platinum group metals that can treat many types of hazardous wastes, has a short process flow, and is highly efficient. Summary of the invention

[0005] In view of the defects in the existing platinum group metal recycling technology, the present invention provides a novel platinum group metal recycling method, proposes to utilize the composition characteristics of cross-industry hazardous wastes, realize the synergistic enhancement of hazardous and solid wastes through the synergistic effect between elements, and utilizes the advantages that the metal elements in electric furnace dust can be directionally regulated (lead and zinc volatilize into the smoke, and iron captures platinum group metals and enters the alloy), and the gangue components (silicon dioxide, calcium oxide, aluminum oxide, etc.) can be used as partial slag forming agents. Low-melting-point platinum group metal alloys are designed, the smelting temperature is reduced, and the green and efficient recycling of platinum group metals is realized. At the same time, the difficult problems of valuable metals in waste automobile catalysts and electric furnace dust are solved, such as the difficulty in recycling and harmless disposal.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] The present invention provides a method for recovering platinum group metals by synergistically smelting waste automobile catalysts and electric furnace dust, comprising the following steps:

[0008] (1) uniformly mixing waste automobile catalyst, electric furnace dust, carbon reducing agent and slag forming agent to obtain a mixture, wherein the mass ratio of the waste automobile catalyst to the electric furnace dust is (60-80): (40-20);

[0009] (2) roasting the mixture obtained in step (1) to remove volatile matter and moisture in the raw materials;

[0010] (3) Smelting and collecting the calcined product obtained in step (2) at high temperature to obtain glassy slag and an iron alloy containing platinum group metals.

[0011] As a further illustration of the present invention, in step (1), the ternary basicity of the mixture: the ratio of the sum of the masses of CaO and MgO to the mass of SiO2 is between 0.5 and 0.7.

[0012] As a further illustration of the present invention, in step (1), the mass of the carbon reducing agent is 4.5wt% to 6wt% of the mass of the electric furnace dust, and the mass of the carbon reducing agent is 1.2 to 1.6 times the theoretical amount for complete reduction of iron oxides in the electric furnace dust.

[0013] As a further illustration of the present invention, in step (1), the carbon reducing agent is metallurgical coke or coal powder.

[0014] As a further illustration of the present invention, in step (1), the slag-forming agent is one or more of calcium oxide, magnesium oxide and silicon dioxide.

[0015] As a further illustration of the present invention, in step (1), the electric furnace dust, the waste automobile catalyst, the carbon reducing agent and the slag-forming agent are all crushed into powders of 150-250 mesh.

[0016] As a further illustration of the present invention, the calcination operation in step (2) is carried out in a muffle furnace, and the calcination temperature is 850-1000° C. and the calcination time is 1-2 hours.

[0017] As a further illustration of the present invention, the smelting operation of the roasted product in step (3) is carried out in a DC arc furnace, and the smelting temperature is 1500-1600° C. and the smelting time is 0.5-1 h.

[0018] As a further illustration of the present invention, the slag system of the calcined product obtained in step (2) is a five-element slag system of SiO2-CaO-Al2O3-MgO-FeO, and the mass proportions of SiO2, CaO, Al2O3, MgO and FeO in the slag system are: SiO2:CaO:Al2O3:MgO:FeO=(43.5~52.9):(23.7~26.4):(18.4~24.2):(4~8.2):(0~2).

[0019] As a further illustration of the present invention, after step (3), the process further includes taking out the melt after it is naturally cooled, and then separating the iron alloy containing platinum group metals from the glassy slag to obtain a platinum group metal alloy.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] (1) For the two hazardous wastes of waste automobile catalysts and electric furnace dust, we fully utilize the composition characteristics of cross-industry hazardous wastes for synergistic utilization, and adopt the electric arc furnace carbon thermal-melting coupled reduction treatment process to simultaneously achieve the recovery of platinum group metals and the resource utilization and harmlessness of cross-industry hazardous wastes.

[0022] (2) The waste automobile catalyst and electric furnace dust are smelted together to treat two types of hazardous solid wastes at the same time, which is environmentally friendly. The gangue components of the two types of cross-industry hazardous wastes can be used to obtain the basic slag system (SiO2-CaO-Al2O3-MgO-FeO) for smelting and capture and the platinum group metal capture source. At the same time, the amount of additional collectors and slag-forming agents added is effectively reduced, saving costs.

[0023] (3) The carbon thermal-melt coupled reduction process is used to achieve the removal of impurities and the enrichment and recovery of platinum group metals. Compared with the traditional iron capture process, the entire recovery process has the advantages of low smelting temperature, short process flow, less input materials, and high recovery efficiency, and is suitable for industrial production.

[0024] (4) By optimizing the slag composition during the smelting process and selecting a suitable slag system, the slag can be vitrified during the smelting process, and the heavy metal ions in the waste automobile catalyst can be converted into a stable solidified structure to achieve harmless disposal. The obtained glassy slag can remain stable for a long time, reducing environmental risks.

[0025] (5) The upper layer of the smelting product is glassy slag, and the lower layer is an alloy containing platinum group metals. The two layers can be easily separated after cooling. In addition, the synergistic smelting of automobile waste catalyst and electric furnace dust can reduce the content of platinum group metals in the slag to less than 10g / t. The comprehensive recovery rate of platinum group metals is above 98%, achieving efficient recovery of platinum group metals.

[0026] Other features and advantages of the technical solution will be described in the subsequent description, and partly become apparent from the description, or understood by implementing the technical solution. The purpose and other advantages of the technical solution can be achieved and obtained through the structures specifically pointed out in the written description and the drawings.

[0027] The technical solution of the present technical solution is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the technical solution and constitute a part of the specification. Together with the embodiments of the technical solution, they are used to explain the technical solution and do not constitute a limitation of the technical solution. In the accompanying drawings:

[0029] Figure 1 A flow chart of a method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust provided in an embodiment of the present invention.

[0030] Figure 2 The microstructure SEM and phase XRD diagram of the glass slag obtained in Example 7 of the present invention.

[0031] Figure 3 The microstructure SEM and phase XRD diagram of the iron alloy containing platinum group metals obtained in Example 7 of the present invention. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present technical solution are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present technical solution, and are not used to limit the present technical solution.

[0033] The present invention provides a method for recovering platinum group metals by co-smelting waste automobile catalysts and electric furnace dust, comprising the following steps:

[0034] (1) Mechanically crush waste automobile catalysts, electric furnace dust, carbon reducing agent, and slagging agent (calcium oxide, magnesium oxide, and silicon dioxide) to a powder particle size between 150 and 250 meshes.

[0035] (2) The crushed waste automobile catalyst, electric furnace dust, carbon reducing agent, calcium oxide, magnesium oxide and silicon dioxide are uniformly mixed in a certain proportion to obtain a mixture.

[0036] The mass ratio of waste automobile catalyst and electric furnace dust is controlled to be (60-80): (40-20), and the carbon reducing agent is metallurgical coke or coal powder, the mass of the carbon reducing agent is controlled to be 4.5wt%-6wt% of the mass of the electric furnace dust, and the mass of the carbon reducing agent is 1.2-1.6 times the theoretical amount for complete reduction of iron oxides in the electric furnace dust. The ternary basicity of the mixture: the ratio of the sum of the mass of CaO and MgO to the mass of SiO2 is between 0.5 and 0.7.

[0037] (3) placing the mixture obtained in step (2) into a muffle furnace and roasting it at 850-1000° C. for 1-2 h, and controlling the mass ratio of the raw materials so that the slag system after roasting is a SiO2-CaO-Al2O3-MgO-FeO quinary slag system, and the mass ratio of SiO2, CaO, Al2O3, MgO and FeO in the slag system is: SiO2:CaO:Al2O3:MgO:FeO=(43.5-52.9):(23.7-26.4):(18.4-24.2):(4-8.2):(0-2).

[0038] (4) placing the calcined product obtained in step (3) into a DC arc furnace and smelting it at 1500-1600° C. for 0.5-1 h.

[0039] (5) During the arc furnace smelting process, since the density of the platinum group metal alloy is greater than that of the slag, the slag will be in the upper layer and the platinum group metal alloy will be in the lower layer. After the smelting is completed, the upper layer of slag is poured out first, and glass slag is obtained after cooling. The remaining is the iron alloy containing the platinum group metal. After the platinum group metal alloy is naturally cooled in the graphite crucible, it is taken out from the graphite crucible and subsequently separated to obtain the platinum group metal.

[0040] The following is a detailed description of a method for recovering platinum group metals by co-smelting waste automobile catalysts and electric furnace dust provided by the present invention in conjunction with examples. The compositions of the waste automobile catalysts and electric furnace dust used in the following examples are shown in the following table.

[0041] Table 1 Main component contents of waste automobile catalysts

[0042]

[0043] Table 2 Main components of electric furnace dust

[0044]

[0045] The ternary basicity of the mixed materials obtained in the following embodiments all satisfy: the ratio of the sum of the masses of CaO and MgO to the mass of SiO2 is between 0.5 and 0.7, and the slag system after roasting the mixture is a SiO2-CaO-Al2O3-MgO-FeO five-element slag system, and the mass proportions of SiO2, CaO, Al2O3, MgO and FeO in the slag system are: SiO2:CaO:Al2O3:MgO:FeO=(43.5~52.9):(23.7~26.4):(18.4~24.2):(4~8.2):(0~2).

[0046] Example 1

[0047] A method for recovering platinum group metals by co-smelting waste automobile catalysts and electric furnace dust is provided, comprising the following steps:

[0048] 1. Take the above 0.6 kg of waste automobile catalyst and 0.4 kg of electric furnace dust and crush them in a sample making machine to 200 mesh.

[0049] 2. Evenly mix the crushed waste automobile catalyst with electric furnace dust, 0.05kg silicon dioxide, 0.03kg calcium oxide, 0.024kg carbon reducing agent and 0.003kg magnesium oxide flux. The waste automobile catalyst contains 42.21% Al2O3, 21.35% SiO2 and 1989g / t Pd, the electric furnace dust contains 87.57% Fe2O3, and the carbon reducing agent is mainly composed of metallurgical coke (fixed carbon content is 69.7%, ash content is 7.65%, and volatile matter is 16.13%).

[0050] 3. The mixed materials are placed in a muffle furnace and fully roasted at 900°C for 1 hour. After roasting, they are placed in a DC arc furnace for smelting and capture at a smelting temperature of 1500°C for 1 hour. The smelting process is naturally stratified, with the upper layer being glass slag and the lower layer being an iron alloy containing platinum group metals.

[0051] 4. After the smelting is completed, the upper part of the slag liquid in the graphite crucible is poured into another graphite crucible. After the remaining part is naturally cooled in the air, it is taken out from the graphite crucible and separated to finally obtain glass slag and ferroalloy containing platinum group metals.

[0052] 5. Finally, the components of the separated glass slag and platinum group metal alloy were determined. The content of platinum group metal in the slag was less than 18g / t, and the recovery rate of platinum group metal was greater than 97%.

[0053] Example 2

[0054] A method for recovering platinum group metals by co-smelting waste automobile catalysts and electric furnace dust is provided, comprising the following steps:

[0055] 1. Take the above 0.6 kg of waste automobile catalyst and 0.4 kg of electric furnace dust and crush them in a sample making machine to 250 mesh.

[0056] 2. Evenly mix the crushed waste automobile catalyst with electric furnace dust, 0.05kg silicon dioxide, 0.03kg calcium oxide, 0.024kg carbon reducing agent and 0.003kg magnesium oxide flux. The waste automobile catalyst contains 42.21% Al2O3, 21.35% SiO2 and 1989g / t Pd, the electric furnace dust contains 87.57% Fe2O3, and the carbon reducing agent is mainly composed of metallurgical coke (fixed carbon content is 69.7%, ash content is 7.65%, and volatile matter is 16.13%).

[0057] 3. The mixed materials are placed in a muffle furnace and fully roasted at 950°C for 1.5 hours. After roasting, they are placed in a DC arc furnace for smelting and capture at a smelting temperature of 1550°C for 1 hour. The smelting process is naturally stratified, with the upper layer being glass slag and the lower layer being an iron alloy containing platinum group metals.

[0058] 4. After the smelting is completed, the upper part of the slag liquid in the graphite crucible is poured into another graphite crucible. After the remaining part is naturally cooled in the air, it is taken out from the graphite crucible and separated to finally obtain glass slag and ferroalloy containing platinum group metals.

[0059] 5. Finally, the components of the separated glass slag and platinum group metal alloy are measured. The content of platinum group metal in the slag is less than 10g / t, and the recovery rate of platinum group metal is greater than 98%.

[0060] Example 3

[0061] A method for recovering platinum group metals by co-smelting waste automobile catalysts and electric furnace dust is provided, comprising the following steps:

[0062] 1. Take the above 0.7 kg of waste automobile catalyst and 0.3 kg of electric furnace dust and crush them in a sample making machine to 150 mesh.

[0063] 2. Evenly mix the crushed waste automobile catalyst with electric furnace dust, 0.058kg silicon dioxide, 0.036kg calcium oxide, 0.0135kg carbon reducing agent and 0.003kg magnesium oxide flux. The waste automobile catalyst contains 42.21% Al2O3, 21.35% SiO2 and 1989g / t Pd, the electric furnace dust contains 87.57% Fe2O3, and the carbon reducing agent is mainly composed of metallurgical coke (fixed carbon content is 69.7%, ash content is 7.65%, and volatile matter is 16.13%).

[0064] 3. The mixed materials are placed in a muffle furnace and fully roasted at 900°C for 1 hour. After roasting, they are placed in a DC arc furnace for smelting and capture at a smelting temperature of 1600°C for 1 hour. The smelting process is naturally stratified, with the upper layer being glass slag and the lower layer being an iron alloy containing platinum group metals.

[0065] 4. After the smelting is completed, the upper part of the slag liquid in the graphite crucible is poured into another graphite crucible. After the remaining part is naturally cooled in the air, it is taken out from the graphite crucible and separated to finally obtain glass slag and ferroalloy containing platinum group metals.

[0066] 5. Finally, the components of the separated glass slag and platinum group metal alloy are measured. The content of platinum group metal in the slag is less than 10g / t, and the recovery rate of platinum group metal is greater than 98%.

[0067] Example 4

[0068] A method for recovering platinum group metals by co-smelting waste automobile catalysts and electric furnace dust is provided, comprising the following steps:

[0069] 1. Take the above 0.7 kg of waste automobile catalyst and 0.3 kg of electric furnace dust and crush them in a sample making machine to 200 mesh.

[0070] 2. Evenly mix the crushed waste automobile catalyst with electric furnace dust, 0.058kg silicon dioxide, 0.036kg calcium oxide, 0.018kg carbon reducing agent and 0.003kg magnesium oxide flux. The waste automobile catalyst contains 42.21% Al2O3, 21.35% SiO2 and 1989g / t Pd, the electric furnace dust contains 87.57% Fe2O3, and the carbon reducing agent is mainly composed of metallurgical coke (fixed carbon content is 69.7%, ash content is 7.65%, and volatile matter is 16.13%).

[0071] 3. The mixed materials are placed in a muffle furnace and fully roasted at 900°C for 1 hour. After roasting, they are placed in a DC arc furnace for smelting and capture at a smelting temperature of 1600°C for 0.5 hours. The smelting process is naturally stratified, with the upper layer being glass slag and the lower layer being an iron alloy containing platinum group metals.

[0072] 4. After the smelting is completed, the upper part of the slag liquid in the graphite crucible is poured into another graphite crucible. After the remaining part is naturally cooled in the air, it is taken out from the graphite crucible and separated to finally obtain glass slag and ferroalloy containing platinum group metals.

[0073] 5. Finally, the components of the separated glass slag and platinum group metal alloy are measured. The content of platinum group metal in the slag is less than 5g / t, and the recovery rate of platinum group metal is greater than 99%.

[0074] Example 5

[0075] A method for recovering platinum group metals by co-smelting waste automobile catalysts and electric furnace dust is provided, comprising the following steps:

[0076] 1. Take the above 0.7 kg of waste automobile catalyst and 0.3 kg of electric furnace dust and crush them in a sample making machine to 200 mesh.

[0077] 2. Evenly mix the crushed waste automobile catalyst with electric furnace dust, 0.058kg silicon dioxide, 0.036kg calcium oxide, 0.018kg carbon reducing agent and 0.003kg magnesium oxide flux. The waste automobile catalyst contains 42.21% Al2O3, 21.35% SiO2 and 1989g / t Pd, the electric furnace dust contains 87.57% Fe2O3, and the carbon reducing agent is mainly composed of metallurgical coke (fixed carbon content is 69.7%, ash content is 7.65%, and volatile matter is 16.13%).

[0078] 3. The mixed materials are placed in a muffle furnace and fully roasted at 950°C for 2 hours. After roasting, they are placed in a DC arc furnace for smelting and capture at a smelting temperature of 1600°C for 0.5 hours. The smelting process is naturally stratified, with the upper layer being glass slag and the lower layer being an iron alloy containing platinum group metals.

[0079] 4. After the smelting is completed, the upper part of the slag liquid in the graphite crucible is poured into another graphite crucible. After the remaining part is naturally cooled in the air, it is taken out from the graphite crucible and separated to finally obtain glass slag and ferroalloy containing platinum group metals.

[0080] 5. Finally, the components of the separated glass slag and platinum group metal alloy were determined. The content of platinum group metal in the slag was less than 5g / t, and the recovery rate of platinum group metal was 99%.

[0081] Example 6

[0082] A method for recovering platinum group metals by co-smelting waste automobile catalysts and electric furnace dust is provided, comprising the following steps:

[0083] 1. Take the above 0.8 kg of waste automobile catalyst and 0.2 kg of electric furnace dust and crush them in a sample making machine to 200 mesh.

[0084] 2. Evenly mix the crushed waste automobile catalyst with electric furnace dust, 0.066kg silicon dioxide, 0.041kg calcium oxide, 0.01kg carbon reducing agent and 0.004kg magnesium oxide flux. The waste automobile catalyst contains 42.21% Al2O3, 21.35% SiO2 and 1989g / t Pd, the electric furnace dust contains 87.57% Fe2O3, and the carbon reducing agent is mainly composed of metallurgical coke (fixed carbon content is 69.7%, ash content is 7.65%, and volatile matter is 16.13%).

[0085] 3. The mixed materials are placed in a muffle furnace and fully roasted at 900°C for 2 hours. After roasting, they are placed in a DC arc furnace for smelting and capture at a smelting temperature of 1600°C for 0.5 hours. The smelting process is naturally stratified, with the upper layer being glass slag and the lower layer being an iron alloy containing platinum group metals.

[0086] 4. After the smelting is completed, the upper part of the slag liquid in the graphite crucible is poured into another graphite crucible. After the remaining part is naturally cooled in the air, it is taken out from the graphite crucible and separated to finally obtain glass slag and ferroalloy containing platinum group metals.

[0087] 5. Finally, the components of the separated glass slag and platinum group metal alloy are measured. The content of platinum group metal in the slag is less than 5g / t, and the recovery rate of platinum group metal is greater than 99%.

[0088] Example 7

[0089] A method for recovering platinum group metals by co-smelting waste automobile catalysts and electric furnace dust is provided, comprising the following steps:

[0090] 1. Take the above 0.8 kg of waste automobile catalyst and 0.2 kg of electric furnace dust and crush them in a sample making machine to 250 mesh.

[0091] 2. Evenly mix the crushed waste automobile catalyst with electric furnace dust, 0.066kg silicon dioxide, 0.041kg calcium oxide, 0.01kg carbon reducing agent and 0.004kg magnesium oxide flux. The waste automobile catalyst contains 42.21% Al2O3, 21.35% SiO2 and 1989g / t Pd, the electric furnace dust contains 87.57% Fe2O3, and the carbon reducing agent is mainly composed of metallurgical coke (fixed carbon content is 69.7%, ash content is 7.65%, and volatile matter is 16.13%).

[0092] 3. The mixed materials are placed in a muffle furnace and fully roasted at 900°C for 2 hours. After roasting, they are placed in a DC arc furnace for smelting and capture at a smelting temperature of 1600°C for 1 hour. The smelting process is naturally stratified, with the upper layer being glass slag and the lower layer being an iron alloy containing platinum group metals.

[0093] 4. After the smelting is completed, the upper part of the slag liquid in the graphite crucible is poured into another graphite crucible. After the remaining part is naturally cooled in the air, it is taken out from the graphite crucible and separated to finally obtain glass slag and ferroalloy containing platinum group metals.

[0094] 5. Finally, the components of the separated glass slag and platinum group metal alloy are measured. The content of platinum group metal in the slag is less than 5g / t, and the recovery rate of platinum group metal is greater than 99%.

[0095] Figure 2 The microstructure SEM and phase XRD diagram of the glass slag obtained in this example. It can be seen from the figure that the alloy obtained after smelting does not generate ferrosilicon alloy, which provides a good alloy standard sample for the subsequent leaching of platinum group metals; Figure 3 The microstructure SEM and phase XRD diagrams of the platinum group metal-containing ferroalloy obtained in this embodiment show that the slag obtained after the coordinated smelting and slag making is a typical amorphous glassy slag, which can effectively "encapsulate" toxic components such as heavy metals to prevent them from "seeping out" during the landfill process.

[0096] Comparative Example 1

[0097] The platinum group metal alloy was prepared according to the method of Example 7, except that the same mass of waste automobile catalyst was used to replace the electric furnace dust:

[0098] 1. Take 1 kg of waste automobile catalyst and crush it in a sample making machine to 250 mesh.

[0099] 2. Evenly mix the crushed waste automobile catalyst with 0.17kg high-purity iron powder, 0.43kg silicon dioxide, 0.2kg magnesium oxide and 0.15kg calcium oxide.

[0100] 3. The mixed materials are placed in a muffle furnace and roasted at 900°C for 2 hours. After roasting, they are placed in a DC arc furnace for smelting and capture. The smelting temperature is 1600°C and the smelting time is 1 hour. The smelting process is naturally stratified, with the upper layer being glass slag and the lower layer being an iron alloy containing platinum group metals.

[0101] 4. After the smelting is completed, the upper part of the slag liquid in the graphite crucible is poured into another graphite crucible. After the remaining part is naturally cooled in the air, it is taken out from the graphite crucible and separated to finally obtain glass slag and ferroalloy containing platinum group metals.

[0102] 5. Finally, the components of the separated glass slag and platinum group metal alloy were determined. The content of platinum group metal in the slag was 9.2 g / t, and the recovery rate of platinum group metal was 98.21%.

[0103] The results of Examples 1-7 and Comparative Example 1 indicate that the method of recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust not only increases the types of hazardous / solid wastes to be treated and reduces the amount of added slag-forming agents and metal collectors, but also improves the recovery rate of platinum group metals and achieves better smelting effects, compared with the use of iron capture technology to recover platinum group metals in waste automobile catalysts alone. Therefore, the method of recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust is feasible.

[0104] Obviously, those skilled in the art can make various changes and modifications to the technical solution without departing from the spirit and scope of the technical solution. Thus, if these modifications and variations of the technical solution fall within the scope of the claims of the technical solution and their equivalents, the technical solution is also intended to include these modifications and variations.

Claims

1. A method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust, characterized in that: The steps include: (1) uniformly mixing waste automobile catalyst, electric furnace dust, carbon reducing agent and slag forming agent to obtain a mixture, wherein the mass ratio of waste automobile catalyst to electric furnace dust is (60-80):(40-20); (2) roasting the mixture obtained in step (1) to remove volatile matter and moisture in the raw materials; (3) The calcined product obtained in step (2) is smelted and captured at high temperature to obtain glassy slag and an iron alloy containing platinum group metals.

2. The method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust as claimed in claim 1, characterized in that: In step (1), the ternary basicity of the mixture: the ratio of the sum of the masses of CaO and MgO to the mass of SiO2 is between 0.5 and 0.

7.

3. The method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust as claimed in claim 1, characterized in that: In step (1), the mass of the carbon reducing agent is 4.5wt%~6wt% of the mass of the electric furnace dust, and the mass of the carbon reducing agent is 1.2~1.6 times the theoretical amount for complete reduction of iron oxides in the electric furnace dust.

4. The method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust as claimed in claim 1, characterized in that: In step (1), the carbon reducing agent is metallurgical coke or coal powder.

5. The method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust as claimed in claim 1, characterized in that: In step (1), the slag-forming agent is one or more of calcium oxide, magnesium oxide and silicon dioxide.

6. The method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust as claimed in claim 1, characterized in that: In step (1), the electric furnace dust, the waste automobile catalyst, the carbon reducing agent and the slag-forming agent are all crushed into powders of 150-250 mesh.

7. The method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust as claimed in claim 1, characterized in that: The calcination operation in step (2) is carried out in a muffle furnace, and the calcination temperature is 850-1000° C. and the calcination time is 1-2 h.

8. The method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust as claimed in claim 1, characterized in that: The slag system of the calcined product obtained in step (2) is a five-element slag system of SiO2-CaO-Al2O3-MgO-FeO, and the mass proportions of SiO2, CaO, Al2O3, MgO and FeO in the slag system are: SiO2:CaO:Al2O3:MgO:FeO=(43.5~52.9):(23.7~26.4):(18.4~24.2):(4~8.2):(0~2).

9. The method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust as claimed in claim 1, characterized in that: The smelting operation of the roasted product in step (3) is carried out in a DC arc furnace, and the smelting temperature is 1500-1600° C. and the smelting time is 0.5-1 h.

10. The method for recovering platinum group metals by synergistic smelting of waste automobile catalysts and electric furnace dust as claimed in claim 1, characterized in that: After step (3), the method further includes taking out the melt after it is naturally cooled, and then separating the iron alloy containing platinum group metals from the glassy slag to obtain a platinum group metal alloy.

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