Refining method, metallurgical device and refining system for platinum group metal lean ore

Abstract

The invention provides a refining method, a metallurgical device and a refining system for platinum group metal lean ore, and relates to the technical field of microwave metallurgy. The refining method comprises the following steps: heating and homogenizing platinum group metal mineral powder through microwave radiation to obtain microwave homogenized mineral powder; carrying out microwave smelting on the microwave homogenized mineral powder to obtain a smelting product; and the smelting product is sequentially subjected to a first-stage separation and enrichment process, blowing treatment and a second-stage separation and enrichment process, and the high-nickel matte is obtained. According to the refining method for the lean ore of the platinum group metal, the ore reaction activity and the energy utilization rate are remarkably improved, the energy consumption is reduced, the refining time is shortened, the platinum group metal recovery rate is increased, meanwhile, SO2 emission is reduced, the production cost is reduced, and the advantages of being efficient, energy-saving and environmentally friendly are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgy, and in particular to a refining method, a metallurgical device and a refining system for platinum group metal lean ore. Background Art

[0002] Platinum group metals (PGMs), due to their unique catalytic properties, corrosion resistance, and electrochemical stability, are widely used in strategic emerging fields such as automotive exhaust purification, chemical catalysts, electronic devices, and hydrogen energy. These metals, including platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os), are extremely rare in the Earth's crust and often occur as depleted ores within copper-nickel sulfide ores or chromite, 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 depleted ores and achieving comprehensive utilization of the associated valuable metals has always been a major technical challenge in the metallurgical field.

[0003] Traditional smelting technology for platinum-group metal (PGM) lean ores primarily relies on a combination of pyrometallurgical and hydrometallurgical processes. Pyrometallurgical processes, including electric furnace smelting, converter converting, and Kaldo furnace refining, concentrate precious metals through high-temperature melting to separate the slag and metal phases. However, these methods have numerous drawbacks. First, pyrometallurgical smelting requires heating the ore to temperatures exceeding 1400°C, relying on electrical heating or fuel combustion, with energy consumption accounting for 40%-60% of the overall cost. Second, the slag-to-metal ratio in traditional processes is as high as 10:1, resulting in the loss of precious metals through dispersion within the slag and recovery rates of less than 70%. Furthermore, the process is complex, requiring multiple smelting-converting cycles and intermediate product processing, resulting in refining cycles lasting 20-30 hours. Finally, the high-temperature process generates large amounts of sulfur- and arsenic-containing fumes and heavy metal waste slag, which are difficult to handle.

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

[0005] In recent years, microwave metallurgy has been recognized as an innovative approach to platinum group metal (PGM) extraction due to its efficient heating, selective activation, and potential for energy conservation and emission reduction. Microwave energy directly acts on polar molecules or conductive minerals through dielectric loss, inducing localized high temperatures and rapid phase transitions at the molecular scale, thereby accelerating ore decomposition and metal migration. However, existing microwave metallurgy technologies still face bottlenecks. First, ore absorbs microwaves unevenly. Platinum group metals in lean ores are dispersed within heterogeneous gangue. Microwave energy is easily reflected or scattered by low-dielectric-loss minerals (such as SiO2), leading to localized overheating and energy waste. Second, existing solutions often utilize fixed frequencies (such as 2.45 GHz) and constant power, which are difficult to adapt to the varying dielectric properties of different ores, resulting in incomplete smelting or excessive oxidation of the metal phase. Furthermore, slag-matte separation after microwave smelting still relies on traditional gravity settling or magnetic separation, which lacks synergistic optimization with the microwave field, leading to secondary losses of precious metals. Finally, existing technologies do not pay enough attention to the pretreatment of lean 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 in the ore and inert minerals (such as olivine) that encapsulate precious metals, resulting in limited efficiency of subsequent microwave treatment.

[0006] In summary, existing PGM lean ore smelting technologies suffer from high energy consumption, low recovery rates, severe pollution, and insufficient microwave energy utilization. These issues not only limit the efficient extraction of PGMs but also place significant pressure on the environment. Therefore, the development of a metallurgical method that combines efficient pretreatment, precise microwave energy control, and short, clean production processes has become an urgent need in the industry.

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

[0008] The object of the present invention is to provide a refining method, metallurgical device and refining system for platinum group metal lean ore. The refining method for platinum group metal lean ore significantly improves the reactivity and energy utilization rate of the ore, reduces energy consumption, shortens the refining time, and improves the recovery rate of platinum group metals. At the same time, it reduces SO2 emissions and lowers production costs, thereby combining the advantages of high efficiency, energy saving and environmental protection.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted: In a first aspect, the present invention provides a method for refining a platinum group metal lean ore, comprising: Platinum group metal ore powder is subjected to heating and homogenization treatment by microwave radiation to obtain microwave homogenized ore powder; subjecting the microwave homogenized mineral powder to microwave smelting to obtain a smelting 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 subjected to heating and homogenization treatment by microwave radiation, the process further comprises: Performing physical crushing and chemical pretreatment 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 chemical pretreatment leachate is at least one of a sulfuric acid solution, a hydrochloric acid solution, a sulfuric acid-hydrochloric acid mixed acid solution, and a sodium hydroxide solution; Preferably, the treatment time of the chemical pretreatment is 2 hours to 6 hours.

[0011] In an optional embodiment, in the heating homogenization treatment, the frequency of the microwave radiation 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 treatment time of the microwave radiation is 10 minutes ~ 40 minutes.

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

[0013] In an optional embodiment, the first-stage separation and enrichment process and the second-stage separation and enrichment process both include at least one method selected from the group consisting of cooling, gravity sedimentation, magnetic separation, and chemical leaching.

[0014] In an optional embodiment, the separation time of gravity sedimentation 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 of the first separation and enrichment process uses aqua regia solution or a cyanide solution; and / or, the leaching time of the chemical leaching of the first separation and enrichment process is 3 hours to 8 hours; and / or, the chemical leaching of the second separation and enrichment process uses a copper sulfate solution or a ferric chloride solution; and / or, the leaching time of the chemical leaching of the second separation and enrichment process is 2 hours to 6 hours.

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

[0016] In a second aspect, the present invention provides a metallurgical device for implementing the refining method of platinum group metal lean ore as described in any of the aforementioned embodiments, comprising a microwave homogenization reactor, a smelting and blowing mechanism, and a separation and enrichment system connected in sequence; Wherein, the microwave homogenization reactor comprises a multi-mode 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 a slag mouth automatic 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 device further comprises a pretreatment unit; the pretreatment unit comprises a crusher and a chemical leaching tank.

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

[0018] In a third aspect, the present invention provides a refining system comprising the metallurgical device as described in the aforementioned embodiment, and a flue gas purification and recovery module connected to the metallurgical device; Wherein, the flue gas purification and recovery module includes a bag filter and a precious metal adsorption tower.

[0019] The refining method of platinum group metal lean ore provided in this application achieves significant beneficial effects through the innovative combination of microwave radiation heating homogenization treatment, microwave smelting and segmented separation and enrichment process. First, microwave radiation treatment can quickly and evenly heat the ore powder, increase the reactivity of the ore, and provide a better raw material basis for subsequent smelting. Secondly, the absorption of microwave energy by the ore powder during microwave smelting is more uniform, which greatly improves the energy utilization efficiency. Compared with traditional fire smelting technology, energy consumption can be reduced by 50%-60%. At the same time, this method directly connects microwave smelting with the blowing process, eliminating the complex links of multiple smelting-blowing cycles and intermediate product reprocessing in traditional processes, shortening the entire refining time from 20 hours to 30 hours to 8 hours to 12 hours, significantly improving production efficiency. In addition, through the two-stage separation and enrichment process, the recovery rate of platinum group metals is significantly improved, and the comprehensive recovery rate can be increased to 85% to 92%, minimizing the residue of precious metals in the slag phase. In terms of environmental protection, the use of inert gas protection during the microwave melting process effectively reduces SO2 emissions in the flue gas (controlling it below 50mg / m³). Furthermore, through efficient flue gas purification and heavy metal capture technologies, the heavy metal capture rate reaches over 99%, making it more environmentally friendly. Finally, due to the simplified process flow, reduced energy consumption, and improved precious metal recovery rates, the overall production cost of this refining method has been significantly reduced. Slag volume has been reduced to 1 / 3 to 1 / 2 of that of traditional processes, auxiliary material consumption has been reduced by 40% to 50%, and overall production costs have been reduced by 25% to 30%, significantly improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 Schematic diagram of the process of refining a platinum group metal lean ore in an embodiment of the present application; Figure 2 This is a schematic diagram of the overall process of the refining method including physical crushing and chemical pretreatment in the embodiment of the present application; Figure 3 This is a schematic diagram of the structure and connection of the refining system in the embodiment of the present application.

[0022] Reference numerals: 100, refining system; 1, metallurgical device; 11, microwave homogenization reactor; 12, smelting and blowing mechanism; 13, separation and enrichment system; 2, flue gas purification and recovery module. DETAILED DESCRIPTION

[0023] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all commercially available conventional products.

[0024] refer to Figure 1 In the embodiments of the present application, a method for refining a platinum group metal lean ore is provided, comprising: Step S1, heating and homogenizing platinum group metal ore powder 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, a process known as microwave absorption property adaptation. The ore powder is uniformly heated under the action of microwave radiation, resulting in microwave-homogenized ore powder. This process achieves a more uniform temperature distribution in the ore powder, providing a more stable raw material for subsequent smelting.

[0026] Step S2: subjecting the microwave homogenized mineral powder to microwave smelting to obtain a smelting product.

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

[0028] Step S3, subjecting the smelting product to a first-stage separation and enrichment process, a blowing process, and a second-stage separation and enrichment process in sequence to obtain high-nickel matte.

[0029] The smelted product undergoes the first stage of separation and enrichment. This process initially concentrates the platinum group metals to produce a low-nickel matte. This process removes some impurities and increases the concentration of the platinum group metals.

[0030] The low-nickel matte is then blown to remove impurities and further enrich the platinum group metals, resulting in a blown product. The blowing process removes impurities through oxidation reactions, increasing the purity of the metal.

[0031] Finally, the converted product undergoes a second stage of separation and enrichment. Further separation and enrichment ultimately yields high-nickel matte. This process further increases the grade of the platinum group metals, resulting in a high-purity metal product.

[0032] refer to Figure 2 In some embodiments, before the step S1 of heating and homogenizing the platinum group metal ore powder by microwave radiation, the step further includes: Step S4: Physically crushing and chemically pre-treating the target platinum group metal lean ore to obtain platinum group metal ore powder.

[0033] In this step, the depleted PGM ore (target depleted PGM ore) is subjected to physical crushing and chemical pretreatment to prepare active PGM ore powder. The order of the treatments can be physical crushing and chemical pretreatment, either sequentially or with chemical pretreatment. In this embodiment, physical crushing and chemical pretreatment are performed sequentially.

[0034] Among them, physical crushing can be achieved by using a jaw crusher and a ball mill to crush the raw ore into a particle size of 50-200 mesh (for example, 50 mesh, 60 mesh, 80 mesh, 100 mesh, 120 mesh, 150 mesh, 180 mesh, 200 mesh, etc.), preferably 80 mesh-150 mesh, so that the specific surface area of the ore is increased to 2m 2 / g ~5m 2 / g, promoting the penetration of subsequent chemical reagents.

[0035] Furthermore, the chemical pretreatment is acid leaching and / or alkali leaching.

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

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

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

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

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

[0041] In some embodiments, 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, and the like.

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

[0043] The above steps are to adapt the active mineral powder to its wave-absorbing characteristics through microwave radiation.

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

[0045] To balance the temperature field, dynamic powder tumbling and multi-mode resonant cavity design keep the internal temperature difference of the powder ≤50°C, ensuring uniform absorption of microwave energy. This treatment results in a microwave-homogenized powder (absorption uniformity ≥95%, moisture content ≤1wt%).

[0046] In some embodiments, the temperature of microwave melting is 1200° C. to 1500° C. For example, it can be 1200° C., 1300° C., 1400° C., 1500° C., and so on.

[0047] In some embodiments, the microwave melting time is 30 minutes to 90 minutes, for example, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, etc.

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

[0049] The melting conditions include: heating to 1200°C~1500°C (preferably 1350°C~1450°C) at a rate of 10°C / min~20°C / min under nitrogen or argon protection, and holding for 30 minutes~90 minutes to promote the melting and separation of the sulfide and metal phases.

[0050] In some embodiments, the first separation and enrichment process and the second separation and enrichment process both include at least one method selected from the group consisting of cooling, gravity sedimentation, magnetic separation, and chemical leaching.

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

[0052] In some embodiments, the magnetic field strength of the magnetic separation is 0.5 T to 1.5 T. For example, the magnetic field strength may be 0.5 T, 0.8 T, 1.0 T, 1.2 T, 1.3 T, 1.4 T, 1.5 T, and the like.

[0053] In some embodiments, the chemical leaching in the first stage separation and enrichment process uses aqua regia solution or cyanide solution; In some embodiments, the leaching time of the chemical leaching in the first separation and enrichment process is 3 hours 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 in the second stage separation and enrichment process uses a copper sulfate solution or a ferric chloride solution.

[0055] In some embodiments, the leaching time of the chemical leaching in the second separation and enrichment process is 2 hours 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 may be 1300° C., 1400° C., 1500° C., 1600° C., and so on.

[0057] In some embodiments, the blowing time of the blowing process is 1 hour 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 of the blowing treatment 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 smelting product is naturally cooled to 800℃~1000℃, the following operations can be carried out in sequence: (1) Gravity sedimentation: The slag phase is allowed to stand in a sedimentation tank for 1 to 4 hours, and the density difference is used to separate the slag phase (density 2.5 g / cm³ to 3.5 g / cm³) and the low-nickel matte (density 5.0 g / cm³ to 6.5 g / cm³); Magnetic separation enhancement: A wet magnetic separator with a magnetic field strength of 0.5 T to 1.5 T is used 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 with aqua regia (HNO3=1:3) or sodium cyanide solution (concentration 0.5%~2%) for 3 hours to 8 hours to further recover the dispersed precious metals.

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

[0061] After the first stage of separation and enrichment treatment, 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 the converter for blowing and deep enrichment: Blowing conditions: Introduce industrial pure oxygen through the top oxygen lance at a rate of 10L / min·t~30L / min·t, control the furnace temperature at 1300℃~1600℃, and blow for 1 hour~3 hours to promote the oxidation of impurities such as iron and sulfur to form FeO-SiO2 slag.

[0063] Second stage separation and enrichment: After the blown product is cooled to 600℃~800℃, the following operations are carried out in sequence: Gravity Sedimentation: Separates high-nickel matte (density 6.5g / cm³~7.5g / cm³) from converting slag (density 3.0g / cm³~4.0g / cm³) in inclined settling tanks.

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

[0065] The final output 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 may be adopted according to the examples of the present application: ‌(1)Ore pretreatment optimization‌: High-organic matter ores: Use a combined pretreatment of alkaline leaching (NaOH 15%, 60℃, 4h) → acid leaching (H2SO4 20%, 50℃, 2h), with an organic matter removal rate of ≥95%.

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

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

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

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

[0071] Second stage separation: Gravity settling (1.5h) + copper sulfate leaching (10%, 4h) is used to increase the recovery rate of platinum group metals to 88%~92%.

[0072] In an embodiment of the present application, a metallurgical device is provided, comprising a microwave homogenization reactor, a microwave smelting furnace, and a separation and enrichment system connected in sequence.

[0073] The microwave homogenization reactor includes a multi-mode resonant cavity and a power-adjustable microwave source.

[0074] The microwave homogenization reactor described above is the initial stage of the entire metallurgical plant. Its primary function is to pre-treat depleted platinum group metal ores, achieving a more uniform distribution of their composition. This is crucial for the subsequent smelting and separation processes, as uneven ore can lead to localized overheating and uneven composition, impacting the quality and yield of the final product.

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

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

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

[0078] The microwave melting furnace described above is used to further melt the homogenized ore, bringing it to a physical state suitable for separation and enrichment. Microwave melting offers advantages such as rapid temperature rise and efficient energy transfer, significantly shortening melting times and improving production efficiency. Temperature sensors monitor temperature changes during the melting process in real time, ensuring that the process remains within the optimal temperature range. This facilitates precise control of the melting process and avoids problems caused by excessively high or low temperatures. An inert gas shielding system (such as argon) is used to prevent oxidation of the ore during high-temperature melting. Platinum group metals are highly sensitive to oxidation, making inert gas protection a key measure for ensuring metal purity and quality.

[0079] The converter blowing unit is used to further blow the microwave-melted product to remove impurities and enrich platinum-group metals. Its components include: an oxygen lance for introducing oxygen into the converter for oxidative blowing; and an automatic slag opening control system for automatically controlling the opening and closing of the slag opening to ensure a smooth blowing process.

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

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

[0082] In some embodiments, the metallurgical plant further comprises a pre-treatment unit; the pre-treatment unit comprises a crusher and a chemical leaching tank.

[0083] The pretreatment unit performs preliminary processing on the raw ore, making it more suitable for subsequent refining. Pretreatment removes impurities, adjusts the ore's particle size and composition, and improves the efficiency of the entire refining process. Crusher units break down large ore into smaller particles, increasing the ore's surface area for subsequent homogenization and smelting. Chemical leaching tanks use chemical methods to initially remove some impurities from the ore, reducing its complexity and increasing the efficiency of platinum group metal enrichment.

[0084] In summary, the metallurgical device achieves efficient refining of depleted PGM ores through the coordinated operation of a microwave homogenization reactor, a microwave melting furnace, and a separation and enrichment system. This device not only improves the uniformity and efficiency of ore processing, but also ensures the purity and recovery of PGMs through measures such as inert gas protection and chemical leaching. Furthermore, the inclusion of a pretreatment unit further optimizes the overall refining process, making it more efficient and flexible. This device is particularly suitable for processing depleted PGM ores and has significant industrial application value.

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

[0086] Furthermore, the microwave source power of the microwave melting furnace ranges from 10kW to 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 In an embodiment of the present application, a refining system is provided, comprising a metallurgical device as described in any of the aforementioned embodiments, and a flue gas purification and recovery module connected to the metallurgical device; wherein the flue gas purification and recovery module comprises a bag dust collector and a precious metal adsorption tower.

[0089] The refining system consists of three main components: (1) Metallurgical unit: This includes a microwave homogenization reactor, a smelting and blowing mechanism, and a separation and enrichment system, all connected in sequence. It also includes an optional pretreatment unit. (2) Flue gas purification and recovery module: This module is used to process and recover the flue gas generated during the blowing process.

[0090] The flue gas purification and recovery module is used to treat flue gas generated during the blowing process, reducing environmental pollution and recovering precious metals. Its structure includes a bag filter for removing dust from the flue gas and reducing the particulate matter content; and a precious metal adsorption tower for adsorbing and recovering precious metals from the flue gas, improving resource utilization.

[0091] For example, the following process may be included: (1) Pretreatment: If necessary, the platinum group metal lean ore is physically crushed and chemically pretreated to obtain platinum group metal ore powder. (2) Microwave homogenization treatment: The platinum group metal ore powder is heated and homogenized by microwave radiation to obtain microwave homogenized ore powder. (3) Microwave smelting: The microwave homogenized ore powder is microwave smelted to obtain a smelting product. (4) Separation and enrichment and converter blowing: The smelting product is sequentially subjected to the first stage of separation and enrichment process, blowing treatment, and the second stage of separation and enrichment process to obtain high-nickel matte. Among them, 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 process 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 is further described below by way of specific examples. However, it should be understood that these examples are merely provided for more detailed description and are not to be construed as limiting the present invention in any form.

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

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

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

[0096] Experimental method (refer to Table 1 for specific parameters): (1) Physically crushing and chemically pre-treating the target platinum group metal lean ore to obtain the platinum group metal ore powder; wherein the ore powder is crushed to 80 mesh and has a specific surface area of 3.8m 2 / g; acid leaching pretreatment: H2SO4 25%, liquid-solid ratio 5:1, stirring at 60℃ for 4h to remove Fe³⁺ and carbonate.

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

[0098] (3) subjecting the microwave homogenized mineral powder to microwave smelting to obtain a smelting product; wherein, the microwave smelting is carried out under nitrogen protection, with a heating rate of 15°C / min to 1400°C and a heat preservation time of 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) The low-nickel matte is blown to produce a blown product, which is then subjected to a second stage separation and enrichment process to obtain a high-nickel matte. The process involves oxygen blowing in a converter (20 L / min·t, 1500°C), followed by copper sulfate leaching (12%, 5 hours), resulting in a concentrate with a PGMs content of 2150 g / t.

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

[0102] Target platinum group metal lean ore raw materials: chromite associated with platinum group ore, PGMs 2.8g / t, SiO248%, Al2O312%.

[0103] Experimental methods: The same as in Example 1, the specific parameters are as follows (see Table 1): Pretreatment: Crushed to 120 mesh, adding 2% NH4F to enhance crushing; Alkali leaching pretreatment: NaOH 18%, liquid-to-solid ratio 6:1, stirring at 80℃ for 5h to dissolve silicate.

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

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

[0106] ‌First stage separation‌: Gravity sedimentation for 3 hours → Aqua regia leaching (2 hours), slag residue ≤ 55g / t.

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

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

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

[0110] Target PGM lean ore raw material: PGM grade 3.5g / t, 5% organic matter, 20% sulfide.

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

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

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

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

[0117] Target PGM lean ore material‌: PGMs 4.1g / t, Ni 20%, sulphide 5%.

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

[0119] Microwave treatment: 2.45 GHz, 15 W / g, 20 min, water 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 of 88%, slag volume reduction of 60%, and concentrate grade of 2200g / t.

[0123] Example 5: Treatment of Arsenic-Containing Lean Ore (As 2%) In this embodiment, a refining process is performed on a target platinum group metal lean ore.

[0124] Target PGM lean ore material: PGMs 2.9g / t, As 2%, sulphides 25%.

[0125] Experimental methods: The same as in Example 1, the specific parameters are as follows (see Table 1): Pretreatment: oxidative acid leaching (HNO3 10% × 5h, 80℃) + 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] Effect: PGMs recovery rate is 85%, As emission is ≤1mg / m³, and As in concentrate is ≤0.02%.

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

[0131] Target PGM lean ore raw material: PGMs 1.2g / t, SiO2 55%, Fe 18%.

[0132] Experimental methods: The same as in Example 1, the specific parameters are as follows (see Table 1): Pretreatment: ultrafine grinding (200 mesh) + alkaline leaching (NaOH 12% × 6h, 80℃), silicate dissolution rate 90%.

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

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

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

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

[0137] Example 7: Treatment of Copper-Nickel Mixed Lean Ore (Cu 8%, Ni 15%) In this embodiment, a refining process is performed on a target platinum group metal lean ore.

[0138] Target PGM lean ore material: PGMs 3.8g / t, Cu 8%, Ni 15%.

[0139] Experimental methods: The same as in Example 1, the specific parameters are as follows (see Table 1): Pretreatment: Acid leaching (H2SO4 25% + NH4F 1.5% × 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] Effect: PGMs recovery rate is 90%, and copper by-product grade is ≥85%.

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

[0145] Target PGM lean ore material‌: PGMs 2.5g / t, C 4%, sulphides 18%.

[0146] Experimental methods: The same as in Example 1, the specific parameters are as follows (see Table 1): Pretreatment: calcination (600℃×2h) + acid leaching (H2SO418%×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] Effect: Recovery rate 87%, total time 12h, concentrate C content ≤ 0.1%.

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

[0152] Target PGM lean ore raw material: PGMs 3.0g / t, MgO 30%, SiO2 25%.

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

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

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

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

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

[0158] Example 10: Treatment of lean ore with associated polymetallic minerals (Cu-Ni-Pb-Zn) In this embodiment, a refining process is performed on a target platinum group metal lean ore.

[0159] Target PGM lean ore raw material‌: PGMs 4.5g / t, Cu 6%, Ni 12%, Pb 3%.

[0160] Experimental methods: The same as in Example 1, the specific parameters are as follows (see Table 1): Pretreatment: staged 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] ‌Effect‌: PGMs recovery rate is 92%, and comprehensive metal recovery rate is ≥88%.

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

[0166] In Table 2, column A is a comparative example, and column B is an example for comparison.

[0167] Comparative Example 1: Traditional Fire 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%, slag residue 120g / t, SO2 emission 200mg / m 3 .

[0170] Comparative Example 2: No chemical pretreatment (Comparative Example 2) ‌Process‌: Only physically crushed to 120 mesh and directly microwave melted.

[0171] Results: The PGMs exposure rate was only 45%, the recovery rate was 62%, and the 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 performed on the organic ore.

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

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

[0175] Comparative Example 4: Treatment of sulfide ore at a fixed microwave frequency (corresponding to Example 4) ‌Process defect‌: Using 2.45GHz high-frequency microwaves on low-sulfur, high-nickel ores (not suitable for sulfide activation).

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

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

[0178] Comparative Example 5: Direct Smelting of Arsenic-Containing Ore (Corresponding to Example 5) ‌Process defect‌: Arsenic-containing ore is not pretreated and is directly smelted.

[0179] Parameters: Melting temperature: 1450℃.

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

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

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

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

[0184] Comparative Example 7: No magnetic separation process (corresponding to Example 7) ‌Process defect‌: The copper-nickel mixed ore was not magnetically separated, but only gravity settled.

[0185] Parameters: Melting at 1400℃.

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

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

[0188] Parameters: Melting at 1350°C.

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

[0190] Comparative Example 9: No fluoride leaching (corresponding to Example 9) ‌Process defect‌: HF is not added for leaching of high-magnesium ore.

[0191] Parameters: Melting temperature: 1370℃.

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

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

[0194] Parameters: Melting temperature: 1430℃.

[0195] Results: The PGMs recovery rate was 69% (92% in Example 10), and the 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) In terms of platinum group metal recovery rates, the platinum group metal recovery rates of Examples 1 to 10 were all between 85% and 92%, indicating that the method of the present invention can achieve efficient recovery in different types of platinum group metal lean 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 platinum group metal recovery and were unable to fully utilize the precious metal resources in the ore.

[0199] (2) The energy consumption of Examples 1 to 10 ranged from 0.8 to 1.2 tons of standard coal per ton of ore (tce / t ore), demonstrating the significant energy-saving advantages of the method of the present invention. The average energy consumption of Comparative Examples 1 to 10 was 2.3 tce / t ore, with the lowest being 1.8 tce / t ore, significantly higher than that of the Examples. This indicates that the Comparative Examples that did not adopt the technical solution of the present invention had significant deficiencies in energy efficiency, resulting in increased production costs.

[0200] (3) The refining time range of Examples 1 to 10 was 8 to 12 hours, significantly shortening the refining cycle of the conventional process. The average refining time of Comparative Examples 1 to 10 was 28 hours, with the shortest being 20 hours, far exceeding that of the Examples. This indicates that the process flow of the comparative examples that did not adopt the technical solution of the present invention was relatively complex, with low production efficiency, and could not meet the requirements of modern industry for efficient production.

[0201] (4) The SO2 emissions of Examples 1 to 10 were all controlled at 50 mg / m 3 The following shows the significant advantages of the method of the present invention in terms of environmental protection. The SO2 emissions of Comparative Examples 1 to 10 are between 180 and 300 mg / m 3 This indicates that the comparative example process that does not adopt the technical solution of the present invention has a greater pressure on environmental protection and may cause environmental pollution problems.

[0202] (5) The residual PGM content in the slags of Examples 1 to 10 was all controlled below 55 g / t, demonstrating the significant advantages of the present invention in reducing precious metal losses. The average residual PGM content in the slags of Comparative Examples 1 to 10 was above 100 g / t, with the highest reaching 180 g / t. This indicates that the comparative example processes that do not employ the technical solution of the present invention suffer significant losses during precious metal recovery, resulting in waste of resources.

[0203] In summary, as demonstrated in Examples 1 to 10, the present invention achieves the core advantages of 85% to 92% recovery, energy consumption of 0.8 to 1.2 tce / t of ore, and refining time of 8 to 12 hours for a variety of platinum group metal-depleted ores. This significantly outperforms the conventional process used in the comparative example (recovery ≤ 75%, energy consumption ≥ 2.0 tce / t of ore, refining time ≥ 20 hours). Furthermore, the present method excels in environmental protection, significantly reducing SO₂ emissions and significantly reducing the amount of platinum group metals remaining in the slag, offering 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, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 method for refining platinum group metal lean ore, characterized in that: include: Platinum group metal ore powder is subjected to heating and homogenization treatment by microwave radiation to obtain microwave homogenized ore powder; subjecting the microwave homogenized mineral powder to microwave smelting to obtain a smelting 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.

2. The method for refining a low-grade platinum group metal ore according to claim 1, wherein: Before the platinum group metal ore powder is subjected to a heating and homogenizing treatment by microwave radiation, the method further comprises: Performing physical crushing and chemical pretreatment 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 chemical pretreatment leachate is at least one of a sulfuric acid solution, a hydrochloric acid solution, a sulfuric acid-hydrochloric acid mixed acid solution, and a sodium hydroxide solution; Preferably, the treatment time of the chemical pretreatment is 2 hours to 6 hours.

3. The method for refining platinum group metal lean ore according to claim 1, characterized in that: In the heating homogenization treatment, the frequency of microwave radiation is 2.45 GHz ± 50 MHz or 915 MHz ± 25 MHz; and / or, The microwave power density of the microwave radiation is 5W / g to 20W / g; and / or, The microwave radiation treatment time is 10 minutes to 40 minutes.

4. The method for refining a low-grade platinum group metal ore according to claim 1, wherein: The microwave melting temperature is 1200° C. to 1500° C.; and / or, The microwave melting time is 30 minutes to 90 minutes.

5. The method for refining a low-grade platinum group metal ore according to claim 1, wherein: The first stage separation and enrichment process and the second stage separation and enrichment process both include at least one method selected from the group consisting of cooling, gravity sedimentation, magnetic separation, and chemical leaching.

6. The method for refining a low-grade platinum group metal ore according to claim 5, wherein: The separation time of the gravity sedimentation 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 separation and enrichment process adopts aqua regia solution or cyanide solution; and / or, The leaching time of the chemical leaching in the first stage separation and enrichment process is 3 hours to 8 hours; and / or, The chemical leaching in the second stage separation and enrichment process adopts copper sulfate solution or ferric chloride solution; and / or, The leaching time of the chemical leaching in the second stage separation and enrichment process is 2 hours to 6 hours.

7. The method for refining a low-grade platinum group metal ore according to claim 1, wherein: The blowing temperature of the blowing treatment is 1300° C. to 1600° C.; and / or, The blowing time of the blowing treatment is 1 hour to 3 hours; and / or, The oxygen introduction rate during the blowing process of the blowing treatment is 10 L / min·t~30 L / min·t.

8. A metallurgical device for implementing the refining method of platinum group metal lean ore according to any one of claims 1 to 7, characterized in that: It includes a microwave homogenization reactor, a smelting and blowing mechanism and a separation and enrichment system connected in sequence; Wherein, the microwave homogenization reactor comprises a multi-mode 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 a slag mouth automatic 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 device further comprises a pretreatment unit; the pretreatment unit comprises a crusher and a chemical leaching tank.

9. The metallurgical device according to claim 8, characterized in that: The microwave melting furnace is provided with a double-layer heat-insulating structure, the inner layer of which is a zirconia refractory material and the outer layer is a silicon carbide composite material; Preferably, the microwave source power of the microwave melting furnace ranges from 10kW to 50kW; Preferably, the frequency of the microwave melting furnace can be switched to 2.45 GHz or 915 MHz.

10. A refining system, characterized in that: comprising the metallurgical device according to claim 8, and a flue gas purification and recovery module connected to the metallurgical device; Wherein, the flue gas purification and recovery module includes a bag filter and a precious metal adsorption tower.

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