Method for recovering platinum group metal and rare earth in spent automobile three-way catalyst

Abstract

The invention relates to the field of recycling of rare and noble metal secondary resources. The invention particularly relates to a method for recovering platinum group metals and rare earth in a spent automobile three-way catalyst. The invention relates to a method for recovering platinum group metal and rare earth in a spent automobile three-way catalyst. The method comprises the following steps: A, crushing and fine grinding; b, uniformly mixing and briquetting; C, vacuum high-temperature smelting; d, fine crushing and magnetic separation; and E, acid leaching. The method has the advantages of simple process flow, high resource recovery rate, environmental protection and the like, and has wide industrial application prospects.

Description

Technical Field

[0001] The present invention relates to the field of recycling of secondary resources of rare and precious metals, and in particular to a method for recycling platinum group metals and rare earths in failed automobile three-way catalysts. Background Art

[0002] Platinum group metals are widely used in high-tech fields such as automobiles, petrochemicals, new energy, electronic technology, pharmaceuticals, and national defense due to their unique physical and chemical properties. Platinum group metals are scarce and unevenly distributed. They are mainly distributed in South Africa, Zimbabwe, Russia, Finland, Canada, and the United States, and are regarded as "national strategic reserve metals" by various countries. The global proven reserves of platinum group metals are about 71,000 tons, and my country's proven reserves of platinum group metals are only 80.9 tons, accounting for 0.11% of the global reserves. In addition, my country has the most complete industrial system in the world and needs sufficient supply of platinum group metals as a strategic support for the development of the industrial system. In order to meet the demand, my country needs to import hundreds of tons of platinum group metals from abroad every year. The automobile industry is an important area of ​​platinum group metal consumption. my country's automobile consumption ranks first in the world. The scrapped automobile three-way catalysts are currently the largest secondary resources of platinum group metals. Recovering platinum group metals from failed automobile three-way catalysts is one of the most critical research topics in the field of platinum group metal secondary resource recovery. The current mainstream automotive three-way catalyst is mainly composed of cordierite ceramic carrier, alumina coating, rare earth oxide additives and platinum, palladium and rhodium active components. Automobile three-way catalyst is listed as HW50 hazardous waste in my country. Recovering platinum group metals from failed automobile three-way catalysts can not only alleviate the contradiction between supply and demand of platinum group metals in my country, but also reduce the harm caused by hazardous waste to the environment.

[0003] The recycling of spent automotive three-way catalysts is mainly based on the process of pyrometallurgical enrichment and wet refining to recover platinum group metals, and the attention paid to the recovery of rare earths is far less than that of platinum group metals. The reason is that the high-abundance rare earths such as lanthanum and cerium added to automotive three-way catalysts have low economic value, but rare earths are also important national strategic resources, and the recovery of rare earth secondary resources has received more and more attention from the country. Therefore, it is of great significance to recover platinum group metals from spent automotive three-way catalysts while taking into account the recovery of rare earths for resource conservation and environmental protection.

[0004] The schemes proposed in the currently disclosed patents are mainly to firstly treat by acid leaching, alkali leaching or alkali roasting, and then respectively recover rare earth and platinum group metals. Patent CN103031438B proposes wet process steps such as alkali roasting, hot water washing, acid dissolution, extraction and separation of rare earth, HCl / ClO-dissolution, sodium oxide pH adjustment and extraction to recover rare earth elements and platinum group metals in failed automobile catalysts; Patent CN110055423B proposes sodium hydroxide pressure alkali leaching, acid leaching, sulfuric acid double salt precipitation to recover rare earth, acid leaching insoluble slag to recover platinum group metals and other process steps to recover rare earth elements and platinum group metals in failed automobile catalysts; Patent CN110184465B proposes a process route of pressurized acid dissolution to recover rare earth, acid leaching slag pyrometallurgical enrichment of platinum group metals to recover rare earth elements and platinum group metals in failed automobile catalysts; Patent CN118291783A proposes vacuum thermal reduction, magnetic separation, acid leaching and other process steps to recover rare earth elements and residual platinum group metals from pyrometallurgical capture smelting slag.

[0005] Patent CN103031438B and Patent CN110055423B proposed alkali roasting, pressurized alkali leaching and other treatment methods. The above process routes are relatively long, the recovery rates of rare earths and platinum group metals fluctuate greatly, and a large amount of acid and alkali wastewater is also generated. Patent CN110184465B uses pressurized acid dissolution to recover rare earths first, and then leached slag is dried and then pyrometallurgical enrichment of platinum group metals is carried out, which increases the time and energy consumption cost of the process. Patent CN118291783A starts to recover rare earths and residual platinum group metals from smelting slag, which increases the process flow of rare earth and platinum group metal recovery, and the economic value is not high. Overall, the existing patents for the recovery process of rare earths and precious metals in failed automotive three-way catalysts still have certain defects, and the overall recovery efficiency of resources needs to be further improved.

[0006] The process route proposed in this patent adds two processes, vacuum and magnetic separation, to the original pyrometallurgical capture process, which simultaneously enriches rare earth and platinum group metals in the captured metal to form alloys, greatly simplifying the process flow of rare earth and platinum group metal recovery. The magnetic separation process further recovers the alloy particles remaining in the smelting slag, effectively improving the comprehensive recovery rate of rare earth and platinum group metals. In addition, heavy metal lead can be effectively recovered in this process, greatly reducing the harm of the smelting process and smelting slag to the environment. Summary of the invention

[0007] The purpose of the present invention is to provide a method for recovering platinum group metals and rare earths in spent automobile three-way catalysts, which has the advantages of simple process flow, high resource recovery rate, green environmental protection, etc., and has broad industrial application prospects. The problem of efficient recovery of rare earths and platinum group metals in spent automobile three-way catalysts is solved.

[0008] In order to achieve the above object, the technical solution provided by the present invention is: A method for recovering platinum group metals and rare earths from spent automobile three-way catalysts is carried out in the following steps: A. Crushing and fine grinding: The spent automobile three-way catalyst is crushed and finely ground. The particle size of the crushed material is less than 6mm, and the particle size of the finely ground material is 30-300 meshes; B. Mixing and pressing: The finely ground spent automobile three-way catalyst, collector, auxiliary material and reducing agent obtained in step A are mixed in the proportion of 100 parts, 5-20 parts, 50-200 parts and 2-20 parts, and then pressed into agglomerates. The preformed agglomerates are spherical, oblate or ellipsoidal. The parts are by weight. C. Vacuum high temperature smelting: Place the pellets obtained in step B in a vacuum furnace for vacuum high temperature smelting; high temperature smelting is carried out in a closed vacuum furnace with a vacuum degree of 10 -4 ~10 2 Pa, the heating rate is 2-20℃ / min, the temperature is 1300℃-1800℃, and the time is 1-8h; the vacuum equipment is equipped with a metal condenser, and metals such as lead and zinc are condensed at the metal condenser position. After the reaction is completed, alloys containing platinum group metals and rare earth elements, smelting slag, and metals such as lead and zinc are obtained; D. Fine crushing and magnetic separation: The smelting slag obtained in step C is crushed and finely ground to a material particle size of 30 to 300 meshes, and then subjected to magnetic separation equipment for two or more times to separate the residual alloy particles containing platinum group metals and rare earth elements. The magnetic field strength of the magnetic separation equipment is 800 to 8000 Oe. The remaining smelting slag after magnetic separation is used to make glass ceramics and other materials; E. Acid leaching: The alloy containing platinum group metals and rare earths obtained in steps C and D is subjected to acid leaching treatment, the acid concentration is 0.5-18 mol / L, the solid-liquid ratio of the acid to the alloy is 1:1-30 kg / L, the leaching temperature is 10°C-100°C, and the leaching time is 60-120 min, to obtain a rare earth-containing leachate and acid leaching residue; the leachate contains at least one of lanthanum, cerium, praseodymium, neodymium, and yttrium, and lanthanum, cerium, praseodymium, neodymium, and yttrium are in any proportion, and the leachate enters the rare earth separation and extraction process to obtain the corresponding rare earth product; the acid leaching residue contains one, two or three of platinum, palladium, and rhodium, and platinum, palladium, and rhodium are present in any proportion, and the acid leaching residue enters the refining process to obtain platinum, palladium, and rhodium respectively.

[0009] In step B, the collector is one or any combination of ferric oxide, ferroferric oxide, ferrous oxide, iron, nickel oxide, nickel, copper, cupric oxide, cuprous oxide, copper sulfide, and nickel sulfide; the auxiliary material is one or any combination of silicon oxide, sodium carbonate, aluminum oxide, boron oxide, calcium oxide, magnesium oxide, and calcium fluoride; and the reducing agent is one or any combination of silicon powder, carbon powder, aluminum powder, and calcium powder.

[0010] The acid solution in step E is one or any combination of acetic acid, sulfuric acid, hydrofluoric acid, nitric acid, hydrochloric acid and perchloric acid. Beneficial effects of the present invention: 1. The present invention reduces the rare earth oxides in the carrier while recovering the platinum group metals in the failed automobile three-way catalyst, so that the platinum group metals, rare earth metals and the collector form an alloy, and high saturated vapor pressure metals such as lead and zinc are collected at the condenser position, which simplifies the process route for recovering platinum group metals and rare earths in the failed automobile three-way catalyst, effectively improves the comprehensive resource recovery rate, and has obvious economic benefits.

[0011] 2. The method of the present invention captures platinum group metals and reduces and captures rare earth oxides under vacuum and high temperature conditions. Metals with high saturated vapor pressure, such as lead and zinc, are collected at the condenser position. The whole process is simple to operate, and the vacuum process is more environmentally friendly.

[0012] 3. The equipment used in the present invention is conventional equipment in metallurgy or resource recovery process, with high maturity and broad industrialization prospects.

[0013] 4. The present invention adopts a magnetic separation process to further recover the tiny ferroalloys remaining in the smelting slag, effectively improving the recovery rate of platinum group metals and rare earths.

[0014] 5. The smelting slag after magnetic separation described in the present invention is a non-toxic and harmless material, which can be used to prepare glass ceramics or building materials. The whole process is green and environmentally friendly, and the resource utilization rate is high.

[0015] 6. After the acid leaching process of the present invention separates the platinum group metals and rare earth elements, rare earth products and platinum, palladium and rhodium metals can be obtained by using the currently mature industrial process. The process route is mature, which is conducive to the industrial application of the process.

[0016] 7. The present invention realizes a short process and efficient recovery of platinum group metals and rare earth elements in failed automobile three-way catalysts, with a platinum group metal recovery rate greater than 99% and a rare earth recovery rate greater than 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION Example 1

[0018] A method for recovering platinum group metals and rare earths from spent automobile three-way catalysts is carried out in the following steps: A. Crushing and fine grinding: The spent automobile three-way catalyst is crushed and finely ground. The particle size of the crushed material is less than 6mm, and the particle size of the finely ground material is 30 mesh; B. Mixing and pressing: 100g of the finely ground spent automobile three-way catalyst obtained in step A, 15g of ferroferric oxide, 5g of nickel powder, 20g of silicon oxide, 15g of calcium oxide, 20g of aluminum oxide, 5g of magnesium oxide, 5g of sodium carbonate and 2g of silicon powder are mixed thoroughly and then pressed into agglomerates. The preformed pellets are spherical in shape and have a diameter of 20 to 25mm. C. Vacuum high-temperature smelting: The pellets obtained in step B are placed in a vacuum equipment furnace for vacuum high-temperature smelting; the high-temperature smelting is carried out in a closed vacuum equipment furnace, the vacuum degree is 100Pa, the heating rate is 2℃ / min, the temperature is 1300℃, and the time is 8h; the vacuum equipment is equipped with a metal condenser, and metals such as lead and zinc are condensed at the metal condenser position. After the reaction is completed, alloys containing platinum group metals and rare earth elements, smelting slag, and metals such as lead and zinc are obtained; D. Fine crushing and magnetic separation: The smelting slag obtained in step C is crushed and finely ground to a material particle size of 30 mesh, and then subjected to magnetic separation by a magnetic separation device for two or more times to separate the residual alloy particles containing platinum group metals and rare earth elements. The magnetic field strength of the magnetic separation device is 800 Oe and 1500 Oe. The remaining smelting slag after magnetic separation is used to make glass ceramics and other materials; E. Acid leaching: The alloy containing platinum group metals and rare earths obtained in steps C and D is subjected to acid leaching treatment, the hydrochloric acid concentration is 0.5 mol / L, the solid-liquid ratio of hydrochloric acid to alloy is 1:20 kg / L, the leaching temperature is 10°C, the leaching time is 60 min, and a rare earth-containing leachate and acid leaching residue are obtained; the leachate contains at least one of lanthanum, cerium, praseodymium, neodymium and yttrium, and lanthanum, cerium, praseodymium, neodymium and yttrium are in any proportion, and the leachate enters the rare earth separation and extraction process to obtain the corresponding rare earth products; the acid leaching residue contains one, two or three of platinum, palladium and rhodium, and platinum, palladium and rhodium are present in any proportion, and the acid leaching residue enters the refining process to obtain platinum, palladium and rhodium respectively.

[0019] The comprehensive recovery rate of platinum group metals is 99.0%, the comprehensive recovery rate of rare earths is 96.4%, and the recovery rate of lead and zinc is 99.2%. Example 2

[0020] A method for recovering platinum group metals and rare earths from spent automobile three-way catalysts is carried out in the following steps: A. Crushing and fine grinding: The spent automobile three-way catalyst is crushed and finely ground. The particle size of the material after crushing is less than 6mm, and the particle size of the material after fine grinding is 60 mesh; B. Mixing and pressing: 100g of the finely ground spent automobile three-way catalyst obtained in step A, 15g of nickel oxide, 2g of copper sulfide, 15g of silicon oxide, 15g of calcium oxide, 15g of aluminum oxide, 5g of calcium fluoride and 5g of carbon powder are mixed evenly and then pressed into agglomerates. The preformed agglomerates are spherical in shape and have a diameter of 20 to 25mm. C. Vacuum high-temperature smelting: The pellets obtained in step B are placed in a vacuum equipment furnace for vacuum high-temperature smelting; the high-temperature smelting is carried out in a closed vacuum equipment furnace, the vacuum degree is 10Pa, the heating rate is 5℃ / min, the temperature is 1400℃, and the time is 7h; the vacuum equipment is equipped with a metal condenser, and metals such as lead and zinc are condensed at the metal condenser position. After the reaction is completed, alloys containing platinum group metals and rare earth elements, smelting slag, and metals such as lead and zinc are obtained; D. Fine crushing and magnetic separation: The smelting slag obtained in step C is crushed and finely ground to a particle size of 60 mesh, and then subjected to magnetic separation by a magnetic separation device for two or more times to separate the residual alloy particles containing platinum group metals and rare earth elements. The magnetic field strength of the magnetic separation device is 1000 Oe and 2500 Oe. The remaining smelting slag after magnetic separation is used to make glass ceramics and other materials; E. Acid leaching: The alloy containing platinum group metals and rare earths obtained in steps C and D is subjected to acid leaching treatment, the sulfuric acid concentration is 18 mol / L, the solid-liquid ratio of sulfuric acid to alloy is 1:1 kg / L, the leaching temperature is 100°C, and the leaching time is 60 min, to obtain a rare earth-containing leachate and acid leaching residue; the leachate contains at least one of lanthanum, cerium, praseodymium, neodymium, and yttrium, and lanthanum, cerium, praseodymium, neodymium, and yttrium are in any proportion, and the leachate enters the rare earth separation and extraction process to obtain the corresponding rare earth products; the acid leaching residue contains one, two or three of platinum, palladium, and rhodium, and platinum, palladium, and rhodium are present in any proportion, and the acid leaching residue enters the refining process to obtain platinum, palladium, and rhodium, respectively.

[0021] The comprehensive recovery rate of platinum group metals is 99.5%, the comprehensive recovery rate of rare earths is 97.6%, and the recovery rate of lead and zinc is 99.3%. Example 3

[0022] A method for recovering platinum group metals and rare earths from spent automobile three-way catalysts is carried out in the following steps: A. Crushing and fine grinding: The spent automobile three-way catalyst is crushed and finely ground. The particle size of the material after crushing is less than 6mm, and the particle size of the material after fine grinding is 80 mesh; B. Mixing and pressing: 100g of the finely ground spent automobile three-way catalyst obtained in step A, 5g of nickel sulfide, 30g of silicon oxide, 25g of calcium oxide, 25g of aluminum oxide, 5g of boron oxide and 10g of aluminum powder are mixed thoroughly and then pressed into agglomerates. The preformed pellets are ellipsoidal in shape. C. Vacuum high-temperature smelting: The pellets obtained in step B are placed in a vacuum equipment furnace for vacuum high-temperature smelting; the high-temperature smelting is carried out in a closed vacuum equipment furnace, the vacuum degree is 1Pa, the heating rate is 10℃ / min, the temperature is 1500℃, and the time is 6h; the vacuum equipment is equipped with a metal condenser, and lead, zinc and other metals are condensed at the metal condenser position. After the reaction is completed, alloys containing platinum group metals and rare earth elements, smelting slag and lead, zinc and other metals are obtained; D. Fine crushing and magnetic separation: The smelting slag obtained in step C is crushed and finely ground to a particle size of 80 mesh, and then subjected to magnetic separation by a magnetic separation device for two or more times to separate the residual alloy particles containing platinum group metals and rare earth elements. The magnetic field strength of the magnetic separation device is 1200 Oe and 4000 Oe. The remaining smelting slag after magnetic separation is used to make glass ceramics and other materials; E. Acid leaching: The alloy containing platinum group metals and rare earths obtained in steps C and D is subjected to acid leaching treatment, the sulfuric acid concentration is 1 mol / L, the solid-liquid ratio of sulfuric acid to alloy is 1:10 kg / L, the leaching temperature is 60°C, the leaching time is 100 min, and a rare earth-containing leachate and acid leaching residue are obtained; the leachate contains at least one of lanthanum, cerium, praseodymium, neodymium and yttrium, and lanthanum, cerium, praseodymium, neodymium and yttrium are in any proportion, and the leachate enters the rare earth separation and extraction process to obtain the corresponding rare earth products; the acid leaching residue contains one, two or three of platinum, palladium and rhodium, and platinum, palladium and rhodium are present in any proportion, and the acid leaching residue enters the refining process to obtain platinum, palladium and rhodium respectively.

[0023] The comprehensive recovery rate of platinum group metals is 99.8%, the comprehensive recovery rate of rare earths is 98.2%, and the recovery rate of lead and zinc is 99.4%. Example 4

[0024] A method for recovering platinum group metals and rare earths from spent automobile three-way catalysts is carried out in the following steps: A. Crushing and fine grinding: The spent automobile three-way catalyst is crushed and finely ground. The particle size of the crushed material is less than 6mm, and the particle size of the finely ground material is 100 mesh; B. Mixing and pressing: 100g of the finely ground spent automobile three-way catalyst obtained in step A, 10g of nickel oxide, 10g of ferric oxide, 30g of silicon oxide, 25g of calcium oxide, 20g of aluminum oxide, 10g of magnesium oxide, 5g of sodium carbonate and 15g of calcium powder are mixed thoroughly and then pressed into agglomerates. The preformed pellets are ellipsoidal in shape. C. Vacuum high-temperature smelting: The pellets obtained in step B are placed in a vacuum equipment furnace for vacuum high-temperature smelting; the high-temperature smelting is carried out in a closed vacuum equipment furnace, the vacuum degree is 0.1Pa, the heating rate is 10℃ / min, the temperature is 1650℃, and the time is 5h; the vacuum equipment is equipped with a metal condenser, and metals such as lead and zinc are condensed at the metal condenser position. After the reaction is completed, alloys containing platinum group metals and rare earth elements, smelting slag, and metals such as lead and zinc are obtained; D. Fine crushing and magnetic separation: The smelting slag obtained in step C is crushed and finely ground to a particle size of 100 mesh, and then subjected to magnetic separation by a magnetic separation device for two or more times to separate the residual alloy particles containing platinum group metals and rare earth elements. The magnetic field strength of the magnetic separation device is 1500 Oe and 6000 Oe. The remaining smelting slag after magnetic separation is used to make glass ceramics and other materials; E. Acid leaching: The alloy containing platinum group metals and rare earths obtained in steps C and D is subjected to acid leaching treatment, the acetic acid concentration is 2 mol / L, the solid-liquid ratio of acetic acid to alloy is 1:10 kg / L, the leaching temperature is 60°C, the leaching time is 100 min, and a rare earth-containing leachate and acid leaching residue are obtained; the leachate contains at least one of lanthanum, cerium, praseodymium, neodymium and yttrium, and lanthanum, cerium, praseodymium, neodymium and yttrium are in any proportion, and the leachate enters the rare earth separation and extraction process to obtain the corresponding rare earth products; the acid leaching residue contains one, two or three of platinum, palladium and rhodium, and platinum, palladium and rhodium are present in any proportion, and the acid leaching residue enters the refining process to obtain platinum, palladium and rhodium respectively.

[0025] The comprehensive recovery rate of platinum group metals is 99.6%, the comprehensive recovery rate of rare earths is 95.7%, and the recovery rate of lead and zinc is 99.5%. Example 5

[0026] A method for recovering platinum group metals and rare earths from spent automobile three-way catalysts is carried out in the following steps: A. Crushing and fine grinding: The spent automobile three-way catalyst is crushed and finely ground. The particle size of the crushed material is less than 6mm, and the particle size of the finely ground material is 120 mesh; B. Mixing and pressing: 100g of the finely ground spent automobile three-way catalyst obtained in step A, 5g of cuprous oxide, 30g of silicon oxide, 25g of calcium oxide, 20g of aluminum oxide, 10g of magnesium oxide, 5g of sodium carbonate, 10g of silicon powder and 10g of carbon powder are mixed thoroughly and then pressed into agglomerates. The preformed pellets are ellipsoidal in shape. C. Vacuum high-temperature smelting: The pellets obtained in step B are placed in a vacuum equipment furnace for vacuum high-temperature smelting; the high-temperature smelting is carried out in a closed vacuum equipment furnace, the vacuum degree is 0.01Pa, the heating rate is 15℃ / min, the temperature is 1750℃, and the time is 4h; the vacuum equipment is equipped with a metal condenser, and metals such as lead and zinc are condensed at the metal condenser position. After the reaction is completed, alloys containing platinum group metals and rare earth elements, smelting slag, and metals such as lead and zinc are obtained; D. Fine crushing and magnetic separation: The smelting slag obtained in step C is crushed and finely ground to a particle size of 120 mesh, and then subjected to magnetic separation by a magnetic separation device for two or more times to separate the residual alloy particles containing platinum group metals and rare earth elements. The magnetic field strength of the magnetic separation device is 1600 Oe and 6000 Oe. The remaining smelting slag after magnetic separation is used to make glass ceramics and other materials; E. Acid leaching: The alloy containing platinum group metals and rare earths obtained in steps C and D is subjected to acid leaching treatment, the hydrochloric acid concentration is 0.5 mol / L, the hydrofluoric acid concentration is 0.5 mol / L, the hydrochloric acid and the hydrofluoric acid are mixed in a volume ratio of 1:1, the solid-liquid ratio of the mixed acid solution to the alloy is 1:1-30 kg / L, the leaching temperature is 60°C, the leaching time is 120 min, and a rare earth-containing leachate and acid leaching residue are obtained; the leachate contains at least one of lanthanum, cerium, praseodymium, neodymium, and yttrium, and lanthanum, cerium, praseodymium, neodymium, and yttrium are in any proportion, and the leachate enters the rare earth separation and extraction process to obtain the corresponding rare earth products; the acid leaching residue contains one, two or three of platinum, palladium, and rhodium, and platinum, palladium, and rhodium exist in any proportion, and the acid leaching residue enters the refining process to obtain platinum, palladium, and rhodium respectively.

[0027] The comprehensive recovery rate of platinum group metals is 99.3%, the comprehensive recovery rate of rare earths is 97.7%, and the recovery rate of lead and zinc is 99.7%. Example 6

[0028] A method for recovering platinum group metals and rare earths from spent automobile three-way catalysts is carried out in the following steps: A. Crushing and fine grinding: The spent automobile three-way catalyst is crushed and finely ground. The particle size of the crushed material is less than 6mm, and the particle size of the finely ground material is 150 mesh; B. Mixing and pressing: 100g of the finely ground spent automobile three-way catalyst obtained in step A, 5g of copper oxide, 5g of nickel sulfide, 35g of silicon oxide, 25g of calcium oxide, 30g of aluminum oxide, 10g of magnesium oxide, 10g of sodium carbonate, 10g of boron oxide, 10g of carbon powder and 10g of aluminum powder are mixed thoroughly and then pressed into agglomerates. The preformed pellets are in the shape of oblate spheres. C. Vacuum high-temperature smelting: The pellets obtained in step B are placed in a vacuum equipment furnace for vacuum high-temperature smelting; the high-temperature smelting is carried out in a closed vacuum equipment furnace, the vacuum degree is 0.001Pa, the heating rate is 15℃ / min, the temperature is 1750℃, and the time is 3h; the vacuum equipment is equipped with a metal condenser, and lead, zinc and other metals are condensed at the metal condenser position. After the reaction is completed, alloys containing platinum group metals and rare earth elements, smelting slag and lead, zinc and other metals are obtained; D. Fine crushing and magnetic separation: The smelting slag obtained in step C is crushed and finely ground to a particle size of 150 mesh, and then subjected to magnetic separation by a magnetic separation device for two or more times to separate the residual alloy particles containing platinum group metals and rare earth elements. The magnetic field strength of the magnetic separation device is 1800 Oe and 5000 Oe. The remaining smelting slag after magnetic separation is used to make glass ceramics and other materials; E. Acid leaching: The alloy containing platinum group metals and rare earths obtained in steps C and D is subjected to acid leaching treatment, the nitric acid concentration is 0.5 mol / L, the solid-liquid ratio of nitric acid to alloy is 1:20 kg / L, the leaching temperature is 50°C, the leaching time is 120 min, and a rare earth-containing leachate and acid leaching residue are obtained; the leachate contains at least one of lanthanum, cerium, praseodymium, neodymium and yttrium, and lanthanum, cerium, praseodymium, neodymium and yttrium are in any proportion, and the leachate enters the rare earth separation and extraction process to obtain the corresponding rare earth products; the acid leaching residue contains one, two or three of platinum, palladium and rhodium, and platinum, palladium and rhodium are present in any proportion, and the acid leaching residue enters the refining process to obtain platinum, palladium and rhodium respectively.

[0029] The comprehensive recovery rate of platinum group metals is 99.5%, the comprehensive recovery rate of rare earths is 96.1%, and the recovery rate of lead and zinc is 99.9%. Example 7

[0030] A method for recovering platinum group metals and rare earths from spent automobile three-way catalysts is carried out in the following steps: A. Crushing and fine grinding: The spent automobile three-way catalyst is crushed and finely ground. The particle size of the crushed material is less than 6mm, and the particle size of the finely ground material is 200 mesh; B. Mixing and pressing: 100g of the finely ground spent automobile three-way catalyst obtained in step A, 5g of copper powder, 15g of iron powder, 40g of silicon oxide, 40g of calcium oxide, 40g of aluminum oxide, 40g of magnesium oxide, 20g of sodium carbonate, 20g of boron oxide, 10g of aluminum powder and 10g of calcium powder are mixed thoroughly and then pressed into pre-molded pellets. The pre-molded pellets are in the shape of oblate spheres. C. Vacuum high temperature smelting: Place the pellets obtained in step B in a vacuum furnace for vacuum high temperature smelting; high temperature smelting is carried out in a closed vacuum furnace with a vacuum degree of 10 -4 Pa, heating rate of 15℃ / min, temperature of 1750℃, time of 2h; vacuum equipment equipped with metal condenser, lead, zinc and other metals are condensed at the metal condenser position, and alloys containing platinum group metals and rare earth elements, smelting slag and lead, zinc and other metals are obtained after the reaction; D. Fine crushing and magnetic separation: The smelting slag obtained in step C is crushed and finely ground to a particle size of 200 mesh, and then subjected to magnetic separation by a magnetic separation device for two or more times to separate the residual alloy particles containing platinum group metals and rare earth elements. The magnetic field strength of the magnetic separation device is 2000 Oe and 6000 Oe. The remaining smelting slag after magnetic separation is used to make glass ceramics and other materials; E. Acid leaching: The alloy containing platinum group metals and rare earths obtained in steps C and D is subjected to acid leaching treatment, the concentration of perchloric acid is 1 mol / L, the solid-liquid ratio of perchloric acid to alloy is 1:5 kg / L, the leaching temperature is 90°C, the leaching time is 90 min, and a rare earth-containing leachate and acid leaching residue are obtained; the leachate contains at least one of lanthanum, cerium, praseodymium, neodymium and yttrium, and lanthanum, cerium, praseodymium, neodymium and yttrium are in any proportion, and the leachate enters the rare earth separation and extraction process to obtain the corresponding rare earth products; the acid leaching residue contains one, two or three of platinum, palladium and rhodium, and platinum, palladium and rhodium are present in any proportion, and the acid leaching residue enters the refining process to obtain platinum, palladium and rhodium respectively.

[0031] The comprehensive recovery rate of platinum group metals is 99.1%, the comprehensive recovery rate of rare earths is 97.3%, and the recovery rate of lead and zinc is 99.8%. Example 8

[0032] A method for recovering platinum group metals and rare earths from spent automobile three-way catalysts is carried out in the following steps: A. Crushing and fine grinding: The spent automobile three-way catalyst is crushed and finely ground. The particle size of the crushed material is less than 6mm, and the particle size of the finely ground material is 300 mesh; B. Mixing and pressing: 100g of the finely ground spent automobile three-way catalyst obtained in step A, 5g of copper oxide, 15g of nickel oxide, 35g of silicon oxide, 25g of calcium oxide, 30g of aluminum oxide, 10g of magnesium oxide, 10g of silicon powder and 10g of calcium powder are mixed thoroughly and then pressed into agglomerates. The preformed pellets are in the shape of oblate spheres. C. Vacuum high-temperature smelting: The pellets obtained in step B are placed in a vacuum equipment furnace for vacuum high-temperature smelting; the high-temperature smelting is carried out in a closed vacuum equipment furnace, the vacuum degree is 10Pa, the heating rate is 20℃ / min, the temperature is 1800℃, and the time is 1h; the vacuum equipment is equipped with a metal condenser, and lead, zinc and other metals are condensed at the metal condenser position. After the reaction is completed, alloys containing platinum group metals and rare earth elements, smelting slag and lead, zinc and other metals are obtained; D. Fine crushing and magnetic separation: The smelting slag obtained in step C is crushed and finely ground to a material particle size of 300 mesh, and then subjected to magnetic separation by a magnetic separation device for two or more times to separate the residual alloy particles containing platinum group metals and rare earth elements. The magnetic field strength of the magnetic separation device is 2000 Oe and 8000 Oe. The remaining smelting slag after magnetic separation is used to make glass ceramics and other materials; E. Acid leaching: The alloy containing platinum group metals and rare earths obtained in steps C and D is subjected to acid leaching treatment, the sulfuric acid concentration is 4 mol / L, the solid-liquid ratio of sulfuric acid to alloy is 1:5 kg / L, the leaching temperature is 70°C, the leaching time is 90 min, and a rare earth-containing leachate and acid leaching residue are obtained; the leachate contains at least one of lanthanum, cerium, praseodymium, neodymium and yttrium, and lanthanum, cerium, praseodymium, neodymium and yttrium are in any proportion, and the leachate enters the rare earth separation and extraction process to obtain the corresponding rare earth products; the acid leaching residue contains one, two or three of platinum, palladium and rhodium, and platinum, palladium and rhodium are present in any proportion, and the acid leaching residue enters the refining process to obtain platinum, palladium and rhodium respectively.

[0033] The comprehensive recovery rate of platinum group metals is 99.5%, the comprehensive recovery rate of rare earths is 98.7%, and the recovery rate of lead and zinc is 99.8%.

Claims

1. A method for recovering platinum group metals and rare earths from spent automobile three-way catalysts, characterized in that: Follow the steps below: A. Crushing and fine grinding: The spent automobile three-way catalyst is crushed and finely ground. The particle size of the crushed material is less than 6mm, and the particle size of the finely ground material is 30-300 meshes; B. Mixing and pressing: The finely ground spent automobile three-way catalyst, collector, auxiliary material and reducing agent obtained in step A are mixed in the proportion of 100 parts, 5-20 parts, 50-200 parts and 2-20 parts, and then pressed into agglomerates. The preformed agglomerates are spherical, oblate or ellipsoidal. The parts are by weight. C. Vacuum high temperature smelting: Place the pellets obtained in step B in a vacuum furnace for vacuum high temperature smelting; high temperature smelting is carried out in a closed vacuum furnace with a vacuum degree of 10 -4 ~10 2 Pa, the heating rate is 2-20℃ / min, the temperature is 1300℃-1800℃, and the time is 1-8h; the vacuum equipment is equipped with a metal condenser, and metals such as lead and zinc are condensed at the metal condenser position. After the reaction is completed, alloys containing platinum group metals and rare earth elements, smelting slag, and metals such as lead and zinc are obtained; D. Fine crushing and magnetic separation: The smelting slag obtained in step C is crushed and finely ground to a material particle size of 30 to 300 meshes, and then subjected to magnetic separation equipment for two or more times to separate the residual alloy particles containing platinum group metals and rare earth elements. The magnetic field strength of the magnetic separation equipment is 800 to 8000 Oe. The remaining smelting slag after magnetic separation is used to make glass ceramics and other materials; E. Acid leaching: The alloy containing platinum group metals and rare earths obtained in steps C and D is subjected to acid leaching treatment, the acid concentration is 0.5-18 mol / L, the solid-liquid ratio of the acid to the alloy is 1:1-30 kg / L, the leaching temperature is 10°C-100°C, and the leaching time is 60-120 min, to obtain a rare earth-containing leachate and acid leaching residue; the leachate contains at least one of lanthanum, cerium, praseodymium, neodymium, and yttrium, and lanthanum, cerium, praseodymium, neodymium, and yttrium are in any proportion, and the leachate enters the rare earth separation and extraction process to obtain the corresponding rare earth product; the acid leaching residue contains one, two or three of platinum, palladium, and rhodium, and platinum, palladium, and rhodium are present in any proportion, and the acid leaching residue enters the refining process to obtain platinum, palladium, and rhodium respectively.

2. The method for recovering platinum group metals and rare earths from spent automobile three-way catalysts according to claim 1, characterized in that: In step B, the collector is one or any combination of ferric oxide, ferroferric oxide, ferrous oxide, iron, nickel oxide, nickel, copper, cupric oxide, cuprous oxide, copper sulfide, and nickel sulfide; the auxiliary material is one or any combination of silicon oxide, sodium carbonate, aluminum oxide, boron oxide, calcium oxide, magnesium oxide, and calcium fluoride; and the reducing agent is one or any combination of silicon powder, carbon powder, aluminum powder, and calcium powder.

3. A method for recovering platinum group metals and rare earths from spent automobile three-way catalysts according to claim 1 or 2, characterized in that: The acid solution in step E is one or any combination of acetic acid, sulfuric acid, hydrofluoric acid, nitric acid, hydrochloric acid and perchloric acid.

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