A method of refining a platinum group metal poor ore, a metallurgical installation and a refining system

Abstract

The application provides a refining method of a platinum group metal lean ore, a metallurgical device and a refining system, and relates to the technical field of microwave metallurgy. The refining method comprises the following steps: uniformly heating and treating a platinum group metal ore powder through microwave radiation to obtain a microwave homogenized ore powder; microwave smelting the microwave homogenized ore powder to obtain a smelting product; and sequentially subjecting the smelting product to a first-stage separation and enrichment process, a blowing treatment and a second-stage separation and enrichment process to obtain a high-nickel matte. The refining method of the platinum group metal lean ore provided by the application significantly improves the reactivity of the ore and the energy utilization rate, reduces the energy consumption, shortens the refining time, improves the platinum group metal recovery rate, reduces the SO2 emission and reduces the production cost, and has the advantages of high efficiency, energy saving and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, and more specifically, to a refining method, metallurgical apparatus, and refining system for low-grade platinum group metal ores. Background Technology

[0002] Platinum group metals (PGMs) are widely used in strategic emerging fields such as automotive exhaust purification, chemical catalysts, electronic devices, and hydrogen energy due to their unique catalytic properties, corrosion resistance, and electrochemical stability. These metals include platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os). They are extremely rare in the Earth's crust, often occurring as low-grade sulfide copper-nickel or chromite ores, with ore grades generally below 5 g / t. Furthermore, these ores are associated with complex gangue minerals (such as silicates and sulfides) and heavy metal impurities (such as iron, nickel, and copper). Efficiently extracting PGMs from these low-grade ores and achieving comprehensive utilization of associated valuable metals has always been a major technological challenge in the metallurgical field.

[0003] Traditional platinum group metal (PGM) smelting technologies primarily rely on a combination of pyrometallurgical and hydrometallurgical processes. Pyrometallurgical processes include electric furnace smelting, converter blowing, and Kaldor furnace refining, using high-temperature melting to separate the slag and metallic phases and enrich precious metals. However, this method has several drawbacks. First, pyrometallurgical smelting requires heating the ore to above 1400°C, relying on electric heating or fuel combustion, with energy consumption accounting for 40%-60% of the overall cost. Second, in traditional processes, the slag-to-metal ratio is as high as 10:1, leading to the dispersion and loss of precious metals in the slag, with a recovery rate of less than 70%. Furthermore, the process is complex, requiring multiple smelting-blowing cycles and intermediate product processing, with refining cycles lasting 20-30 hours. Finally, the high-temperature process generates large amounts of sulfur- and arsenic-containing flue gas and heavy metal waste slag, which are difficult to treat.

[0004] While hydrometallurgical techniques (such as cyanide leaching and high-pressure acid leaching) can reduce energy consumption, their application is limited by the characteristics of the ore. For example, some ores require ultrafine grinding (particle size <400 mesh) or deep oxidation pretreatment, leading to a surge in processing costs. Furthermore, hydrometallurgical processes suffer from poor leaching selectivity; strong acids or cyanides readily dissolve associated metals such as nickel and copper, necessitating multi-stage extraction or displacement separation, increasing reagent costs. Simultaneously, the leachate contains high concentrations of acid, cyanide, and heavy metal ions, resulting in high environmental remediation costs.

[0005] In recent years, microwave metallurgy technology has been regarded as an innovative direction for platinum group metal extraction due to its high-efficiency heating, selective activation, and energy-saving and emission-reduction potential. Microwave energy acts directly on polar molecules or conductive minerals through dielectric loss, inducing local high temperatures and rapid phase transitions at the molecular scale, thereby accelerating ore decomposition and metal migration. However, existing microwave metallurgy technologies still have bottlenecks. First, the microwave absorption of ores is uneven. In lean ores, platinum group metals are dispersed in heterogeneous gangue, and microwave energy is easily reflected or scattered by low-dielectric-loss minerals (such as SiO2), leading to local overheating and energy waste. Second, existing schemes mostly use fixed frequencies (such as 2.45 GHz) and constant power, which are difficult to match with the changes in dielectric properties of different ores, resulting in incomplete smelting or excessive oxidation of the metal phase. In addition, slag-matte separation after microwave smelting still relies on traditional gravity sedimentation or magnetic separation, without being optimized in conjunction with the microwave field, resulting in secondary loss of precious metals. Finally, existing technologies do not pay enough attention to the pretreatment of low-grade ores. Physical crushing only focuses on particle size control, while chemical pretreatment mostly uses single acid / alkali leaching, which fails to effectively remove organic matter and inert minerals (such as olivine) that encapsulate precious metals from the ore, resulting in limited efficiency of subsequent microwave processing.

[0006] In summary, existing platinum group metal (PGM) smelting technologies generally suffer from high energy consumption, low recovery rates, heavy pollution, and insufficient microwave energy utilization. These problems not only limit the efficient extraction of PGMs but also place significant pressure on the environment. Therefore, developing a metallurgical method that combines efficient pretreatment, precise microwave energy control, and a short-process, clean production has become an urgent need for the industry.

[0007] In view of this, the present invention is hereby proposed. Summary of the Invention

[0008] The purpose of this invention is to provide a refining method, metallurgical apparatus, and refining system for low-grade platinum group metal ores. The refining method for low-grade platinum group metal ores significantly improves the reactivity and energy utilization of the ore, reduces energy consumption, shortens refining time, increases the recovery rate of platinum group metals, and at the same time reduces SO2 emissions and lowers production costs, thus possessing the advantages of high efficiency, energy saving, and environmental protection.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a refining method for platinum group metal low-grade ores, comprising: Platinum group metal ore powder was heated and homogenized by microwave radiation to obtain microwave homogenized ore powder. The microwave homogenized mineral powder is microwave smelted to obtain the smelted product. The smelting product is sequentially subjected to a first-stage separation and enrichment process, a blowing process, and a second-stage separation and enrichment process to obtain high-nickel matte.

[0010] In an optional embodiment, before the platinum group metal ore powder is heated and homogenized by microwave radiation, the process further includes: Physical crushing and chemical pretreatment were performed on the target platinum group metal lean ore to obtain the platinum group metal ore powder. Preferably, the particle size of the ore obtained after the physical crushing treatment is 50 mesh to 200 mesh; Preferably, the chemical pretreatment is acid leaching and / or alkali leaching. Preferably, the leachate from the chemical pretreatment is at least one of sulfuric acid solution, hydrochloric acid solution, sulfuric acid-hydrochloric acid mixed solution, and sodium hydroxide solution; Preferably, the chemical pretreatment process takes 2 to 6 hours.

[0011] In an optional embodiment, the frequency of the microwave radiation in the heating homogenization process is 2.45 GHz ± 50 MHz or 915 MHz ± 25 MHz; and / or, the microwave power density of the microwave radiation is 5 W / g ~ 20 W / g; and / or, the microwave radiation treatment time is 10 minutes to 40 minutes.

[0012] In an optional embodiment, the microwave melting temperature is 1200℃~1500℃; and / or, the microwave melting time is 30 minutes~90 minutes.

[0013] In an optional embodiment, both the first-stage separation and enrichment process and the second-stage separation and enrichment process include at least one of the following methods: cooling, gravity sedimentation, magnetic separation, and chemical leaching.

[0014] In an optional implementation, the separation time of the gravity settling is 1 hour to 4 hours; and / or, The magnetic field strength of the magnetic separation is 0.5T~1.5T; and / or, The chemical leaching in the first stage of the separation and enrichment process uses aqua regia or cyanide solution; and / or, the leaching time of the chemical leaching in the first stage of the separation and enrichment process is 3 to 8 hours; and / or, the chemical leaching in the second stage of the separation and enrichment process uses copper sulfate solution or ferric chloride solution; and / or, the leaching time of the chemical leaching in the second stage of the separation and enrichment process is 2 to 6 hours.

[0015] In an optional embodiment, the blowing temperature of the blowing process is 1300℃~1600℃; and / or, the blowing time of the blowing process is 1 hour~3 hours; and / or, the oxygen introduction rate during the blowing process of the blowing process is 10L / min·t~30L / min·t.

[0016] In a second aspect, the present invention provides a metallurgical apparatus for implementing a refining method for platinum group metal low-grade ores as described in any of the foregoing embodiments, comprising a microwave homogenizing reactor, a smelting and blowing mechanism, and a separation and enrichment system connected in sequence. The microwave homogenization reactor includes a multimode resonant cavity and a power adjustable microwave source. The smelting and blowing mechanism includes a microwave smelting furnace and a converter blowing unit; the converter blowing unit is equipped with an oxygen lance and an automatic slag outlet control system. The microwave melting furnace includes an integrated temperature sensor and an inert gas protection system; The separation and enrichment system includes a gravity settling tank, a magnetic separator, and a leaching reactor; Preferably, the metallurgical apparatus further includes a pretreatment unit; the pretreatment unit includes a crusher and a chemical leaching tank.

[0017] In an optional embodiment, the microwave melting furnace is provided with a double-layer heat insulation structure, with the inner layer being zirconium oxide refractory material and the outer layer being silicon carbide composite material; Preferably, the microwave source power of the microwave melting furnace is in the range of 10kW to 50kW; Preferably, the frequency of the microwave melting furnace can be switched to 2.45 GHz or 915 MHz.

[0018] Thirdly, the present invention provides a refining system, including a metallurgical apparatus as described in the foregoing embodiments, and a flue gas purification and recovery module connected to the metallurgical apparatus. The flue gas purification and recovery module includes a bag filter and a precious metal adsorption tower.

[0019] The refining method for platinum group metal (PGM) lean ores provided in this application achieves significant beneficial effects through an innovative combination of microwave radiation heating homogenization treatment, microwave melting, and staged separation and enrichment processes. First, microwave radiation treatment can rapidly and uniformly heat the ore powder, improving the ore's reactivity and providing a higher-quality raw material basis for subsequent melting. Second, during microwave melting, the ore powder absorbs microwave energy more uniformly, significantly improving energy utilization efficiency; compared to traditional pyrometallurgical melting technology, energy consumption can be reduced by 50%-60%. Simultaneously, this method directly connects microwave melting and blowing processes, eliminating the complex steps of multiple melting-blowing cycles and intermediate product reprocessing in traditional processes, shortening the entire refining time from 20-30 hours to 8-12 hours, significantly improving production efficiency. Furthermore, through a two-stage separation and enrichment process, the recovery rate of PGM is significantly improved, with the overall recovery rate reaching 85%-92%, minimizing the residue of precious metals in the slag phase. In terms of environmental protection, the microwave melting process employs inert gas protection, effectively reducing SO2 emissions in the flue gas (controlled below 50 mg / m³). Furthermore, through efficient flue gas purification and heavy metal capture technologies, the heavy metal capture rate can reach over 99%, making it more environmentally friendly. Finally, due to the simplified process flow, reduced energy consumption, and improved precious metal recovery rate, the overall production cost of this refining method is significantly reduced. Slag volume is reduced to 1 / 3 to 1 / 2 of that in traditional processes, auxiliary material consumption is reduced by 40% to 50%, and overall production costs are reduced by 25% to 30%, resulting in significantly improved economic benefits. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic flowchart of a refining method for low-grade platinum group metal ores in an embodiment of this application. Figure 2 This is a schematic diagram of the overall process of the refining method including physical crushing and chemical pretreatment in the embodiments of this application; Figure 3 This is a schematic diagram of the structure and connection of the refining system in an embodiment of this application.

[0022] Figure label: 100, Refining System; 1, Metallurgical Equipment; 11, Microwave Homogenization Reactor; 12, Melting and Blowing Mechanism; 13, Separation and Enrichment System; 2, Flue Gas Purification and Recovery Module. Detailed Implementation

[0023] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0024] refer to Figure 1 This application provides a refining method for low-grade platinum group metal ores, comprising: Step S1: The platinum group metal ore powder is heated and homogenized by microwave radiation to obtain microwave homogenized ore powder.

[0025] In this step, platinum group metal ore powder (active ore powder) is placed in a microwave radiation device for heating and homogenization treatment, i.e., microwave absorption characteristic adaptation treatment. The ore powder is uniformly heated under microwave radiation to obtain microwave-homogenized ore powder. This process makes the temperature distribution of the ore powder more uniform, providing a more stable raw material for subsequent smelting.

[0026] Step S2: The microwave homogenized mineral powder is microwave smelted to obtain the smelted product.

[0027] In this step, the microwave-homogenized mineral powder is subjected to microwave melting. The mineral powder melts in a microwave field, forming a smelted product. Microwave melting utilizes microwave energy to directly act on the mineral powder, achieving rapid melting and separation.

[0028] Step S3: The smelting product is sequentially processed through a first separation and enrichment process, a blowing process, and a second separation and enrichment process to obtain high-nickel matte.

[0029] The smelting products undergo a first-stage separation and enrichment process. This process initially enriches platinum group metals to obtain low-nickel matte. This process removes some impurities and increases the concentration of platinum group metals.

[0030] The low-nickel matte is then subjected to a blowing process. This blowing process removes impurities and further enriches the platinum group metals, yielding the blown product. The blowing process removes impurities through an oxidation reaction, increasing the purity of the metal.

[0031] Finally, the smelting product undergoes a second stage of separation and enrichment. Through further separation and enrichment, high-nickel matte is obtained. This process further improves the grade of platinum group metals, resulting in a high-purity metal product.

[0032] refer to Figure 2 In some embodiments, before step S1, which involves heating and homogenizing the platinum group metal ore powder using microwave radiation, the method further includes: Step S4 involves physically crushing and chemically pretreating the target platinum group metal ore to obtain platinum group metal powder.

[0033] In this step, the platinum group metal (PGM) lean ore (target PGM) undergoes physical crushing and chemical pretreatment to prepare active PGM ore powder. The order of treatment can be either physical crushing followed by chemical pretreatment, or chemical pretreatment performed first. In this embodiment, physical crushing and chemical pretreatment are performed sequentially.

[0034] Physical crushing can be achieved by combining a jaw crusher and a ball mill to crush the raw ore to a particle size of 50-200 mesh (e.g., 50 mesh, 60 mesh, 80 mesh, 100 mesh, 120 mesh, 150 mesh, 180 mesh, 200 mesh, etc.), preferably 80-150 mesh, thereby increasing the specific surface area of ​​the ore to 2m². 2 / g ~5m 2 / g, promotes the penetration of subsequent chemical reagents.

[0035] Further, the chemical pretreatment includes acid leaching and / or alkali leaching.

[0036] The crushed ore powder can be placed in a leaching tank, and a pretreatment solution (e.g., 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, etc.) can be added at a liquid-to-solid ratio of (3~8):1 L / kg. The mixture can be stirred and treated for 2 to 6 hours (e.g., 2 hours, 3 hours, 4 hours, 5 hours, 80, etc.) at 30℃~80℃ (e.g., 30, 40, 50, 60, 70, 80, etc.).

[0037] The leachate for chemical pretreatment is at least one of sulfuric acid solution, hydrochloric acid solution, sulfuric acid-hydrochloric acid mixed solution, and sodium hydroxide solution. Sulfuric acid (concentration can be 10%-30%, e.g., 10%, 20%, 30%, etc.), hydrochloric acid (concentration can be 5%-15%, e.g., 5%, 6%, 8%, 10%, 12%, 15%, etc.), or a mixture thereof (sulfuric acid-hydrochloric acid mixed solution) is used to dissolve carbonate and iron oxide impurities.

[0038] In the alkaline leaching system, sodium hydroxide solution (concentration can be 5%~20%, for example, 5%, 6%, 7%, 8%, 10%, 12%, 15%, 18%, 20%, etc.) is used to remove silicates and organic matter.

[0039] The pretreated mineral powder is washed and dried to obtain active platinum group metal mineral powder, i.e., platinum group metal mineral powder. Its precious metal exposure rate is ≥90%, and its organic matter content is ≤0.5wt%.

[0040] In some embodiments, the frequency of microwave radiation in the heating homogenization process can be (1) 2.45 GHz ± 50 MHz or (2) 915 MHz ± 25 MHz.

[0041] In some implementations, the microwave power density of the microwave radiation is 5 W / g to 20 W / g. For example, it can be 5 W / g, 6 W / g, 7 W / g, 8 W / g, 9 W / g, 10 W / g, 12 W / g, 14 W / g, 16 W / g, 18 W / g, 20 W / g, etc.

[0042] In some implementations, the microwave radiation treatment time is 10 to 40 minutes. For example, it can be 10 minutes, 20 minutes, 30 minutes, 40 minutes, etc.

[0043] The above steps are for adapting the active mineral powder to microwave absorption characteristics through microwave radiation.

[0044] Among them, microwave parameter adjustment is based on the detection results of the dielectric constant (ε') and loss factor (ε'') of the ore. The microwave frequency can be flexibly selected according to the mineral type, with a frequency of 2.45GHz±50MHz (suitable for high sulfide minerals) or 915MHz±25MHz (suitable for silicate minerals); the power density is controlled between 5W / g and 20W / g (this range can be preferably 8W / g to 15W / g), and the processing time is 10 minutes to 40 minutes.

[0045] Regarding temperature field equalization, dynamic tumbling and multi-mode resonant cavity design of the mineral powder ensures that the internal temperature difference of the mineral powder is ≤50℃, guaranteeing uniform microwave energy absorption. The resulting microwave-homogenized mineral powder has an absorption uniformity ≥95% and a moisture content ≤1wt%.

[0046] In some implementations, the microwave melting temperature is 1200°C to 1500°C. For example, it can be 1200°C, 1300°C, 1400°C, 1500°C, etc.

[0047] In some implementations, the microwave melting time is 30 to 90 minutes. For example, it can be 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, etc.

[0048] In this step, microwave-homogenized mineral powder is fed into a microwave melting furnace for melting and preliminary separation.

[0049] Melting conditions include: heating to 1200℃~1500℃ (preferably 1350℃~1450℃) at a rate of 10℃ / min~20℃ / min under nitrogen or argon protection, and holding at that temperature for 30 minutes~90 minutes to promote the melting and stratification of sulfides and metallic phases.

[0050] In some embodiments, both the first-stage separation and enrichment process and the second-stage separation and enrichment process include at least one of the following methods: cooling, gravity sedimentation, magnetic separation, and chemical leaching.

[0051] In some implementations, the separation time for gravity settling is 1 to 4 hours. For example, the separation time can be 1 hour, 2 hours, 3 hours, or 4 hours.

[0052] In some implementations, the magnetic field strength of the magnetic separation is 0.5T to 1.5T. For example, the magnetic field strength can be 0.5T, 0.8T, 1.0T, 1.2T, 1.3T, 1.4T, 1.5T, etc.

[0053] In some embodiments, the chemical leaching in the first stage of the separation and enrichment process uses an aqueous solution of aqua regia or a cyanide solution; In some embodiments, the leaching time of the chemical leaching in the first separation and enrichment process is 3 to 8 hours; for example, the leaching time can be 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, etc.

[0054] In some embodiments, the chemical leaching of the second-stage separation and enrichment process uses a copper sulfate solution or a ferric chloride solution.

[0055] In some implementations, the leaching time for the chemical leaching in the second-stage separation and enrichment process is 2 to 6 hours. For example, the leaching time can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, etc.

[0056] In some embodiments, the blowing temperature of the blowing process is 1300°C to 1600°C. For example, the blowing temperature can be 1300°C, 1400°C, 1500°C, 1600°C, etc.

[0057] In some implementations, the blowing time for the blowing process is 1 to 3 hours. For example, the blowing time can be 1 hour, 2 hours, 3 hours, etc.

[0058] In some embodiments, the oxygen introduction rate during the blowing process is 10 L / min·t to 30 L / min·t. For example, the rate can be 10 L / min·t, 20 L / min·t, 30 L / min·t, etc.

[0059] Specifically, in the first stage of separation and enrichment, after the smelted product is naturally cooled to 800℃~1000℃, the following operations can be performed sequentially: (1) Gravity settling: Let the mixture stand in the settling tank for 1 to 4 hours to separate the slag phase (density 2.5 g / cm³ to 3.5 g / cm³) and low-nickel matte (density 5.0 g / cm³ to 6.5 g / cm³) by utilizing the density difference; Magnetic separation enhancement: Use a wet magnetic separator with a magnetic field strength of 0.5 T to 1.5 T to recover magnetic metal particles (such as iron-nickel alloy) in the slag phase and incorporate them into the low-nickel matte; (2) Chemical leaching (optional): The residual slag phase is leached for 3 to 8 hours with aqua regia (HNO3=1:3) or sodium cyanide solution (concentration 0.5%~2%) to further recover and disperse precious metals.

[0060] The final product is low-nickel matte (platinum group metal content 200g / t ~ 500g / t, nickel / copper grade 15%~30%) and waste residue (precious metal residue ≤ 50g / t).

[0061] After the first stage of separation and enrichment treatment, the converter oxygen blowing smelting and the second stage of separation and enrichment treatment are carried out.

[0062] First, the low-nickel matte is transferred to a converter for blowing and deep enrichment: Smelting conditions: Industrial pure oxygen is introduced through the top oxygen lance at a rate of 10 L / min·t to 30 L / min·t, the furnace temperature is controlled at 1300℃ to 1600℃, and the smelting time is 1 hour to 3 hours, which promotes the oxidation of impurities such as iron and sulfur to form FeO-SiO2 slag.

[0063] Second stage separation and enrichment: After the blowing product is cooled to 600℃~800℃, the following operations are performed sequentially: Gravity settling: high-nickel matte (density 6.5 g / cm³~7.5 g / cm³) and blowing slag (density 3.0 g / cm³~4.0 g / cm³) are separated in an inclined settling tank.

[0064] Chemical leaching (optional): Selectively leaching nickel and copper with copper sulfate (concentration 5%~15%) or ferric chloride (concentration 3%~10%) solution to obtain platinum group metal concentrate (grade ≥2000g / t).

[0065] The final product is high-nickel matte (platinum group metal content ≥1500g / t, nickel / copper grade ≥50%) and copper-nickel by-products that can be sold externally.

[0066] In a preferred embodiment, the following preferred implementation scheme can be adopted according to the embodiments of this application: (1) Optimization of ore pretreatment: For ores with high organic matter content: a combined pretreatment of alkali leaching (NaOH 15%, 60℃, 4h) → acid leaching (H2SO4 20%, 50℃, 2h) was adopted, and the organic matter removal rate was ≥95%.

[0067] High silicate ore: After crushing to 80~120 mesh, add ammonium fluoride (1%~3%) to enhance silica dissolution.

[0068] (2) Microwave parameter adaptation: Sulfide minerals: 915MHz low-frequency microwave, power density 12W / g, processing time 25 minutes.

[0069] Oxide minerals: Switch to 2.45GHz high-frequency microwave, power density 8W / g, processing time 35 minutes.

[0070] (3) Separation process combination: First stage separation: Gravity settling (2h) + magnetic separation (1.0T) is preferred, and the residual precious metals in the slag are ≤80g / t.

[0071] Second stage separation: using "gravity sedimentation (1.5h) + copper sulfate leaching (10%, 4h)", the recovery rate of platinum group metals is increased to 88%~92%.

[0072] In this embodiment of the application, a metallurgical apparatus is provided, comprising a microwave homogenization reactor, a microwave melting furnace, and a separation and enrichment system connected in sequence.

[0073] The microwave homogenization reactor includes a multimode resonant cavity and a power-tunable microwave source.

[0074] The aforementioned microwave homogenization reactor is the starting point of the entire metallurgical plant. Its main function is to pretreat platinum group metal lean ores, making the composition of the ore more uniformly distributed. This is crucial for subsequent smelting and separation processes, as uneven ore can lead to problems such as localized overheating and compositional inhomogeneity, affecting the quality and yield of the final product.

[0075] The multimode resonant cavity generates multiple microwave modes, ensuring uniform microwave energy distribution throughout the ore. This design avoids localized overheating or insufficient energy, improving the efficiency and uniformity of ore processing. The adjustable microwave source allows for power adjustments based on ore characteristics and processing requirements. This not only enhances equipment flexibility but also optimizes energy efficiency and reduces energy consumption.

[0076] The smelting and blowing mechanism includes a microwave smelting furnace and a converter blowing unit; the converter blowing unit is equipped with an oxygen lance and an automatic slag outlet control system.

[0077] The microwave melting furnace includes an integrated temperature sensor and an inert gas protection system.

[0078] The aforementioned microwave melting furnace is used to further melt homogenized ore, bringing it to a physical state suitable for separation and enrichment. Microwave melting offers advantages such as rapid heating and efficient energy transfer, significantly shortening melting time and improving production efficiency. Temperature sensors monitor temperature changes in real time during the melting process, ensuring it operates within the optimal temperature range. This helps to precisely control the melting process and avoid problems caused by excessively high or low temperatures. An inert gas (such as argon) protection system is used to prevent the ore from oxidizing during high-temperature melting. Platinum group metals are highly sensitive to oxidation; therefore, inert gas protection is a crucial measure to ensure metal purity and quality.

[0079] The converter blowing unit is used to further blow the smelted products after microwave melting to remove impurities and enrich platinum group metals. Structurally, it may include: an oxygen lance for introducing oxygen into the converter for oxidative blowing; and an automatic slag nozzle control system for automatically controlling the opening and closing of the slag nozzle to ensure the smooth operation of the blowing process.

[0080] The separation and enrichment system includes a gravity settling tank, a magnetic separator, and a leaching reactor.

[0081] The aforementioned separation and enrichment system is used to separate and enrich platinum group metals (PGMs) from smelted ore. This system uses physical and chemical methods to separate PGMs from other impurities, improving the metal grade. Gravity settling tanks utilize gravity to allow heavy metals (such as PGMs) in the smelted ore to settle, initially separating heavier metal particles. Magnetic separators utilize the magnetic properties of PGMs to further separate metal particles. Magnetic separation is a highly efficient physical separation method that can significantly improve metal recovery rates. A leaching reactor uses chemical leaching to further extract PGMs from the ore. The leaching reactor can use specific chemical reagents (such as acids and salts) to dissolve the metals, allowing them to enter the solution for subsequent extraction and purification.

[0082] In some embodiments, the metallurgical apparatus further includes a pretreatment unit; the pretreatment unit includes a crusher and a chemical leaching tank.

[0083] The pretreatment unit is used to perform preliminary processing on the raw ore, making it more suitable for subsequent refining processes. Pretreatment can remove impurities from the ore, adjust its particle size and composition, and improve the efficiency of the entire refining process. Specifically, the crusher breaks large pieces of ore into smaller particles, increasing the ore's specific surface area and facilitating subsequent homogenization and smelting. The chemical leaching tank uses chemical methods to initially leach some impurities from the ore, reducing its complexity and improving the enrichment efficiency of platinum group metals.

[0084] In summary, the metallurgical unit achieves highly efficient refining of low-grade platinum group metal ores through the synergistic operation of a microwave homogenization reactor, a microwave melting furnace, and a separation and enrichment system. This unit not only improves the uniformity and efficiency of ore processing but also ensures the purity and recovery rate of platinum group metals through measures such as inert gas protection and chemical leaching. Furthermore, the addition of a pretreatment unit further optimizes the entire refining process, making it more efficient and flexible. This unit is particularly suitable for processing low-grade platinum group metal ores and has significant industrial application value.

[0085] In some embodiments, the microwave melting furnace is provided with a double-layer heat insulation structure, with the inner layer being zirconium oxide refractory material and the outer layer being silicon carbide composite material.

[0086] Furthermore, the microwave source power range of the microwave melting furnace is 10kW~50kW; for example, it can be 10kW, 20kW, 30kW, 40kW, 50kW, etc.

[0087] Furthermore, the frequency of the microwave melting furnace can be switched to 2.45 GHz or 915 MHz.

[0088] refer to Figure 3 This application provides a refining system, including a metallurgical apparatus as described in any of the foregoing embodiments, and a flue gas purification and recovery module connected to the metallurgical apparatus; wherein the flue gas purification and recovery module includes a bag filter and a precious metal adsorption tower.

[0089] The above refining system mainly consists of the following three parts: (1) Metallurgical equipment: including a microwave homogenization reactor, a smelting and blowing mechanism and a separation and enrichment system connected in sequence. In addition, it also includes an optional pretreatment unit. (2) Flue gas purification and recovery module: used to treat and recover the flue gas generated during the blowing process.

[0090] The aforementioned flue gas purification and recovery module is used to treat the flue gas generated during the smelting process, reduce environmental pollution, and recover precious metals from it. Structurally, it may include: a bag filter for removing dust from the flue gas and reducing its particulate matter content; and a precious metal adsorption tower for adsorbing and recovering precious metals from the flue gas, thereby improving resource utilization.

[0091] For example, it can include the following process: (1) Pretreatment: If necessary, the platinum group metal (PGM) lean ore is physically crushed and chemically pretreated to obtain PGM powder. (2) Microwave homogenization: The PGM powder is heated and homogenized by microwave radiation to obtain microwave homogenized powder. (3) Microwave smelting: The microwave homogenized powder is microwave smelted to obtain smelted product. (4) Separation, enrichment and converter blowing: The smelted product is sequentially processed through the first stage of separation and enrichment, blowing treatment and the second stage of separation and enrichment to obtain high-nickel matte. Between the first and second stages, the separated and enriched product (low-nickel matte) is sent to the converter blowing unit for further blowing treatment, and then the second stage of separation and enrichment is carried out. (5) Flue gas treatment and recovery: The flue gas generated during the blowing process is treated by the flue gas purification and recovery module to remove dust and recover precious metals.

[0092] The present invention will be further illustrated below with specific embodiments. However, it should be understood that these embodiments are merely for the purpose of more detailed illustration and should not be construed as limiting the present invention in any way.

[0093] Table 1. Key parameters in Examples 1-10

[0094] Example 1: Treatment of high-sulfide lean ore (sulfide 35%) In this embodiment, a refining process was performed on the target platinum group metal low-grade ore.

[0095] Target platinum group metal low-grade ore raw material: copper-nickel sulfide ore, PGMs grade 3.2 g / t, sulfur content 32%, Fe 25%, SiO2 15%.

[0096] Experimental methods (specific parameters are shown in Table 1): (1) Physical crushing and chemical pretreatment are performed on the target platinum group metal lean ore to obtain the platinum group metal ore powder; wherein, the powder is crushed to 80 mesh and has a specific surface area of ​​3.8 m². 2 / g; Acid leaching pretreatment: H2SO4 25%, liquid-solid ratio 5:1, stirred at 60℃ for 4h to remove Fe³⁺ and carbonates.

[0097] (2) Platinum group metal ore powder is heated and homogenized by microwave radiation to obtain microwave homogenized ore powder; wherein, the heating and homogenization treatment is performed at a frequency of 915MHz, a power density of 12W / g, for 30min, and the temperature difference of the ore powder is ≤40℃.

[0098] (3) The microwave homogenized mineral powder is microwave smelted to obtain the smelted product; wherein, the microwave smelting is carried out under nitrogen protection, the heating rate is 15℃ / min to 1400℃, and the holding time is 60min.

[0099] (4) The smelting product is subjected to a first-stage separation and enrichment process to obtain low-nickel matte; in the first-stage separation, gravity sedimentation for 2 hours → magnetic separation (1.2T), low-nickel matte PGMs 420g / t, slag residue 48g / t.

[0100] (5) Low-nickel matte is smelted to produce smelting products; and the smelting products are subjected to a second-stage separation and enrichment process to obtain high-nickel matte. Among them, oxygen blowing in the converter (20L / min·t, 1500℃), copper sulfate leaching (12%, 5h), and concentrate PGMs 2150g / t.

[0101] Example 2: Treatment of high-silicate lean ore (SiO2 50%) In this embodiment, a refining process was performed on the target platinum group metal low-grade ore.

[0102] Target platinum group metal low-grade ore raw material: chromite associated with platinum group metals, PGMs 2.8g / t, SiO2 48%, Al2O3 12%.

[0103] Experimental methods: The results are basically the same as in Example 1, with the specific parameters as follows (refer to Table 1): Pretreatment: Crush to 120 mesh, add 2% NH4F to enhance crushing; Alkali leaching pretreatment: NaOH 18%, liquid-to-solid ratio 6:1, stirred at 80℃ for 5 hours to dissolve silicates.

[0104] Microwave treatment: frequency 2.45GHz, power density 8W / g, treatment time 40min, mineral powder temperature difference ≤50℃.

[0105] Melting: Argon protection, heating rate 10℃ / min to 1350℃, holding for 90min.

[0106] First stage separation: gravity settling for 3 hours → aqua regia leaching (2 hours), residue ≤55g / t.

[0107] Second stage separation: Oxygen blowing in the converter (15L / min·t, 1450℃), concentrate PGMs 1980g / t.

[0108] Results: Recovery rate 86%, energy consumption 1.1 tce / t ore, total time 12 hours.

[0109] Example 3: Treatment of low-grade ore containing organic matter (5% organic matter) In this embodiment, a refining process was performed on the target platinum group metal low-grade ore.

[0110] Target platinum group metal low-grade ore raw material: platinum group metal grade 3.5 g / t, containing 5% organic matter and 20% sulfides.

[0111] Experimental methods: The results are basically the same as in Example 1, with the specific parameters as follows (refer to Table 1): Pretreatment: crush to 100 mesh, alkali leaching (NaOH 15%, 60℃×4h) → acid leaching (H2SO4 20%, 50℃×2h), organic matter removal rate ≥95%; precious metal exposure rate of mineral powder 93%.

[0112] Microwave treatment: 915MHz, 10W / g, 25min, temperature difference ≤35℃.

[0113] Melting: Nitrogen protection, 1380℃×50min, low-nickel matte PGMs 480g / t.

[0114] Separation process: gravity sedimentation (2.5h) + magnetic separation (1.0T) + cyanide leaching (NaCN 1.5%×6h).

[0115] Results: Recovery rate 91%, total time 10.5h, residue ≤40g / t.

[0116] Example 4: Treatment of low-sulfur, high-nickel ore (Ni 20%) In this embodiment, a refining process was performed on the target platinum group metal low-grade ore.

[0117] Target platinum group metal low-grade ore feedstock: PGMs 4.1g / t, Ni 20%, sulfides 5%.

[0118] Experimental methods: The results are basically the same as in Example 1, with the specific parameters as follows (refer to Table 1): Pretreatment: ball milling to 150 mesh, mixed acid leaching (20% H2SO4 + 10% HCl, 70℃×3h); Ni leaching rate 85%, PGMs exposure rate 95%.

[0119] Microwave treatment: 2.45 GHz, 15 W / g, 20 min, moisture content 0.8 wt%.

[0120] Melting: Argon protection, 1420℃×40min, low-nickel matte Ni 28%.

[0121] Separation process: gravity sedimentation (1.5h) + copper sulfate leaching (10%×5h).

[0122] Results: PGMs recovery rate 88%, slag volume reduced by 60%, concentrate grade 2200g / t.

[0123] Example 5: Treatment of low-grade arsenic-bearing ore (As 2%) In this embodiment, a refining process was performed on the target platinum group metal low-grade ore.

[0124] Target platinum group metal low-grade ore feedstock: PGMs 2.9 g / t, As 2%, sulfides 25%.

[0125] Experimental methods: The results are basically the same as in Example 1, with the specific parameters as follows (refer to Table 1): Pretreatment: Oxidative acid leaching (10% HNO3 for 5 hours, 80°C) + neutralization precipitation (pH 8.5), As removal rate 98%.

[0126] Microwave treatment: 915MHz, 18W / g, 35min, absorption efficiency 88%.

[0127] Melting: Nitrogen protection, 1450℃×60min, low nickel matte As≤0.05%.

[0128] Separation process: Magnetic separation (1.5T) + aqua regia leaching (HNO3=1:3×4h).

[0129] Results: PGMs recovery rate 85%, As emission ≤1mg / m³, As in concentrate ≤0.02%.

[0130] Example 6: Processing of ultra-low grade lean ore (PGMs 1.2 g / t) In this embodiment, a refining process was performed on the target platinum group metal low-grade ore.

[0131] Target platinum group metal low-grade ore raw material: PGMs 1.2g / t, SiO2 55%, Fe 18%.

[0132] Experimental methods: The results are basically the same as in Example 1, with the specific parameters as follows (refer to Table 1): Pretreatment: ultrafine grinding (200 mesh) + alkali leaching (NaOH 12%×6h, 80℃), silicate solubility 90%.

[0133] Microwave treatment: 2.45GHz, 12W / g, 45min, temperature difference ≤50℃.

[0134] Melting: Argon protection, 1300℃×80min, low nickel matte PGMs 180g / t.

[0135] Separation process: Two-stage gravity settling (3h + 2h).

[0136] Results: Recovery rate 83%, energy consumption 1.2tce / t ore, slag residue ≤60g / t.

[0137] Example 7: Treatment of lean copper-nickel mixed ore (Cu 8%, Ni 15%) In this embodiment, a refining process was performed on the target platinum group metal low-grade ore.

[0138] Target platinum group metal low-grade ore raw material: PGMs 3.8g / t, Cu 8%, Ni 15%.

[0139] Experimental methods: The results are basically the same as in Example 1, with the specific parameters as follows (refer to Table 1): Pretreatment: Acid leaching (25% H2SO4 + 1.5% NH4F × 4h, 65℃), Cu / Ni leaching rate ≥ 80%.

[0140] Microwave treatment: 915MHz, 14W / g, 30min, absorption uniformity 94%.

[0141] Melting: Nitrogen protection, 1400℃×45min, low-nickel matte Cu 22%.

[0142] Separation process: Magnetic separation (0.8T) + ferric chloride leaching (FeCl38%×5h).

[0143] Results: PGMs recovery rate 90%, copper by-product grade ≥85%.

[0144] Example 8: Treatment of low-grade ore containing carbonaceous inclusions (C 4%) In this embodiment, a refining process was performed on the target platinum group metal low-grade ore.

[0145] Target platinum group metal low-grade ore feedstock: PGMs 2.5g / t, C 4%, sulfides 18%.

[0146] Experimental methods: The results are basically the same as in Example 1, with the specific parameters as follows (refer to Table 1): Pretreatment: calcination (600℃×2h) + acid leaching (H2SO4 18%×3h), carbon removal rate ≥98%.

[0147] Microwave treatment: 2.45 GHz, 9 W / g, 50 min, mineral powder moisture content ≤0.5%.

[0148] Melting: Nitrogen protection, 1350℃×70min, low nickel matte PGMs 350g / t.

[0149] Separation process: gravity sedimentation (3h) + cyanide leaching (NaCN 2%×7h).

[0150] Results: Recovery rate 87%, total time 12 hours, concentrate C content ≤0.1%.

[0151] Example 9: Treatment of high-magnesium lean ore (MgO 30%) In this embodiment, a refining process was performed on the target platinum group metal low-grade ore.

[0152] Target platinum group metal low-grade ore raw material: PGMs 3.0g / t, MgO 30%, SiO2 25%.

[0153] Experimental methods: The results are basically the same as in Example 1, with the specific parameters as follows (refer to Table 1): Pretreatment: 15% HCl + 2% HF mixed leaching (60℃×5h), MgO solubility ≥85%.

[0154] Microwave treatment: 915MHz, 16W / g, 25min, temperature difference ≤40℃.

[0155] Melting: Argon protection, 1370℃×55min, slag viscosity ≤3Pa·s.

[0156] Separation process: Magnetic separation (1.2T) + copper sulfate leaching (15%×4h).

[0157] Results: PGMs recovery rate 84%, slag volume reduced by 50%.

[0158] Example 10: Processing of low-grade polymetallic associated minerals (Cu-Ni-Pb-Zn) In this embodiment, a refining process was performed on the target platinum group metal low-grade ore.

[0159] Target platinum group metal low-grade ore raw material: PGMs 4.5g / t, Cu 6%, Ni 12%, Pb 3%.

[0160] Experimental methods: The results are basically the same as in Example 1, with the specific parameters as follows (refer to Table 1): Pretreatment: Segmented acid leaching (H2SO4 20%×3h→HCl 12%×2h), multi-metal leaching rate ≥90%.

[0161] Microwave treatment: 915MHz, 12W / g, 35min, absorption uniformity ≥93%.

[0162] Melting: Nitrogen protection, 1430℃×50min, low-nickel matte PGMs 520g / t.

[0163] Separation process: gravity sedimentation (2h) + aqua regia leaching (HNO3=1:3×6h).

[0164] Results: PGMs recovery rate 92%, overall metal recovery rate ≥88%.

[0165] Table 2. Defects in Comparative Examples 1-10

[0166] In Table 2, column A represents the comparative examples, and column B represents the examples used for comparison.

[0167] Comparative Example 1: Traditional Pyrometallurgical Process (Comparative Example 1) Process: Electric furnace smelting (1500℃) → converter blowing → electrolytic refining.

[0168] Parameters: smelting time 8h, blowing time 6h, total energy consumption 2.5tce / t ore.

[0169] Results: PGMs recovery rate 71%, residue 120 g / t, SO2 emission 200 mg / m³ 3 .

[0170] Comparative Example 2: No chemical pretreatment (Comparative Example 2) Process: Physically crushed to 120 mesh, then directly microwave smelted.

[0171] Results: PGMs exposure rate was only 45%, recovery rate was 62%, and smelting time was extended to 120 min.

[0172] Comparative Example 3: Alkali-free pretreatment (corresponding to Example 3) Process defect: No alkaline leaching pretreatment was performed; only acid leaching was used to treat the organic minerals.

[0173] Parameters: Microwave 915MHz, melting 1380℃.

[0174] Results: PGMs recovery rate was 68% (91% in Example 3), and residue residue was 120 g / t.

[0175] Comparative Example 4: Treatment of sulfide minerals with a fixed microwave frequency (corresponding to Example 4) Process defect: 2.45GHz high-frequency microwave was used on low-sulfur, high-nickel ore (not adapted for sulfide activation).

[0176] Parameters: Power 15W / g, melting temperature 1420℃.

[0177] Results: PGMs recovery rate was 73% (88% in Example 4), and low-nickel matte Ni grade was 18%.

[0178] Comparative Example 5: Direct smelting of arsenic-containing ore (corresponding to Example 5) Process defect: Arsenic-containing ore was not pretreated and was directly smelted.

[0179] Parameters: Melting temperature 1450℃.

[0180] Results: PGMs recovery rate was 58% (85% in Example 5), and the As content in the concentrate was 1.2%.

[0181] Comparative Example 6: Conventional ball milling pretreatment (corresponding to Example 6) Process defects: The ultra-low grade ore was only ball-milled to 80 mesh and not alkali-leached.

[0182] Parameters: Microwave 2.45GHz, melting 1300℃.

[0183] Results: PGMs recovery rate was 65% (83% in Example 6), and residue residue was 180 g / t.

[0184] Comparative Example 7: Non-magnetic separation process (corresponding to Example 7) Process defect: The copper-nickel mixed ore was not magnetically separated, but only settled by gravity.

[0185] Parameters: Melting temperature 1400℃.

[0186] Results: PGMs recovery rate was 76% (90% in Example 7), and copper grade was 60%.

[0187] Comparative Example 8: Low-power microwave processing (corresponding to Example 8) Process defect: Microwave power of carbonaceous ore is 5W / g (insufficient).

[0188] Parameters: Melting temperature 1350℃.

[0189] Results: PGMs recovery rate was 70% (87% in Example 8), and concentrate C content was 2.5%.

[0190] Comparative Example 9: Fluoride-free leaching (corresponding to Example 9) Process defect: High magnesium ore was not leached with HF.

[0191] Parameters: Melting temperature 1370℃.

[0192] Results: PGMs recovery rate was 62% (84% in Example 9), and slag viscosity was 8 Pa·s.

[0193] Comparative Example 10: Single-stage smelting process (corresponding to Example 10) Process defect: Polymetallic ores are smelted in a single stage.

[0194] Parameters: Melting temperature 1430℃.

[0195] Results: PGMs recovery rate was 69% (92% in Example 10), and Cu / Ni residue in the slag was 5%.

[0196] The defects in Comparative Examples 1 to 10 are summarized in Table 2.

[0197] Data Comparison: Table 3. Comparison of key indicators between the examples and comparative examples

[0198] analyze: (1) Regarding the recovery rate of platinum group metals, the recovery rates of platinum group metals in Examples 1 to 10 were all between 85% and 92%, demonstrating that the method of the present invention can achieve efficient recovery in different types of low-grade platinum group metal ores. In contrast, the recovery rates of Comparative Examples 1 to 10 were generally lower, with an average of only 67.8% and a maximum of no more than 76%. This indicates that the processes of the comparative examples that did not adopt the technical solution of the present invention were less efficient in the recovery of platinum group metals and could not fully utilize the precious metal resources in the ore.

[0199] (2) The energy consumption range of Examples 1 to 10 is 0.8 to 1.2 tons of standard coal per ton of ore (tce / t ore), demonstrating the significant energy-saving advantage of the method of the present invention. The average energy consumption of Comparative Examples 1 to 10 is 2.3 tce / t ore, with the lowest being 1.8 tce / t ore, which is much higher than that of the Examples. This indicates that the comparative examples that do not adopt the technical solution of the present invention have significant deficiencies in energy utilization efficiency, leading to increased production costs.

[0200] (3) The refining time range of Examples 1 to 10 is 8 to 12 hours, which significantly shortens the refining cycle of the traditional process. In contrast, the average refining time of Comparative Examples 1 to 10 is 28 hours, with the shortest being 20 hours, which is much longer than that of the Examples. This indicates that the comparative process flow that does not adopt the technical solution of this invention is relatively complex and has low production efficiency, which cannot meet the requirements of modern industry for high-efficiency production.

[0201] (4) The SO2 emissions in Examples 1 to 10 were all controlled at 50 mg / m³. 3 The following demonstrates the significant environmental advantages of the method of the present invention. The SO2 emissions of Comparative Examples 1 to 10 were 180–300 mg / m³. 3 The values ​​are significantly higher than in the comparative examples. This indicates that the comparative process, which did not employ the technical solution of this invention, faces considerable environmental pressure and may potentially cause environmental pollution problems.

[0202] (5) The residual platinum group metal content in the slag of Examples 1 to 10 was all controlled below 55 g / t, demonstrating the significant advantage of the method of the present invention in reducing precious metal loss. The residual platinum group metal content in the slag of Comparative Examples 1 to 10 was on average above 100 g / t, with the highest reaching 180 g / t. This indicates that the comparative process that did not adopt the technical solution of the present invention suffered significant losses during precious metal recovery, leading to resource waste.

[0203] In summary, as verified by Examples 1 to 10, this invention achieves core advantages in various platinum group metal (PGM) lean ores, including a recovery rate of 85%–92%, energy consumption of 0.8 tce / t ore to 1.2 tce / t ore, and refining time of 8 to 12 hours. These advantages are significantly superior to the comparative traditional processes (recovery rate ≤75%, energy consumption ≥2.0 tce / t ore, and refining time ≥20 hours). Furthermore, the method of this invention also demonstrates excellent environmental performance, significantly reducing SO2 emissions and the amount of residual PGM metals in the slag, resulting in significant economic and environmental benefits.

[0204] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A refining method for low-grade platinum group metal ores, characterized in that, include: The target platinum group metal lean ore is subjected to physical crushing and chemical pretreatment to obtain platinum group metal ore powder; the chemical pretreatment is acid leaching and / or alkaline leaching. Platinum group metal ore powder was heated and homogenized by microwave radiation to obtain microwave homogenized ore powder. The microwave homogenized mineral powder is microwave smelted to obtain the smelted product. The smelting product is subjected to a first-stage separation and enrichment process to obtain low-nickel matte; Low-nickel matte is smelted to produce smelting products; The smelting product was then subjected to a second-stage separation and enrichment process to obtain high-nickel matte; Both the first-stage separation and enrichment process and the second-stage separation and enrichment process include at least one of gravity sedimentation, magnetic separation, and chemical leaching.

2. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The particle size of the ore obtained after the physical crushing process is 50 mesh to 200 mesh.

3. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The leachate from the chemical pretreatment is at least one of sulfuric acid solution, hydrochloric acid solution, sulfuric acid-hydrochloric acid mixed solution, and sodium hydroxide solution.

4. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The chemical pretreatment process takes 2 to 6 hours.

5. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, In the heating homogenization process, the frequency of microwave radiation is 2.45 GHz or 915 MHz.

6. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The microwave power density of the microwave radiation is 5W / g to 20W / g.

7. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The microwave radiation treatment time is 10 to 40 minutes.

8. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The microwave melting temperature is 1200℃~1500℃.

9. The refining method for platinum group metal lean ore as described in claim 1, characterized in that, The microwave melting time is 30 to 90 minutes.

10. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The separation time for gravity settling is 1 to 4 hours.

11. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The magnetic field strength of the magnetic separation is 0.5T~1.5T.

12. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The chemical leaching in the first stage of the separation and enrichment process uses aqua regia or cyanide solution.

13. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The leaching time for the chemical leaching in the first stage of the separation and enrichment process is 3 to 8 hours.

14. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The chemical leaching in the second stage of the separation and enrichment process uses a copper sulfate solution or a ferric chloride solution.

15. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The leaching time for the chemical leaching in the second stage separation and enrichment process is 2 to 6 hours.

16. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The blowing temperature is 1300℃~1600℃.

17. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The blowing time is 1 to 3 hours.

18. The refining method for platinum group metal lean ores as described in claim 1, characterized in that, The oxygen flow rate during the blowing process is 10 L / min·t to 30 L / min·t.

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