A method for strengthening recovery of antimony slag metal based on oxygen-rich volatilization technology

Abstract

This invention discloses a method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology, relating to the fields of non-ferrous metal smelting and solid waste resource utilization. The method comprises the following components: S1, antimony slag pretreatment; S2, side-blown melting reduction; S3, heating pretreatment; S4, oxygen-enriched volatilization enhancement; S5, valuable metal collection; and S6, recycling. This invention achieves efficient recovery, particularly for low-grade raw materials with antimony content below 5% in antimony-containing waste slag, through a combination of enhanced pretreatment and optimized process parameters. In the pretreatment stage, antimony slag is mixed with calcium oxide and roasted to convert low-valent antimony into easily volatile antimony trioxide. Simultaneously, process parameters are adjusted during the side-blown reduction and oxygen-enriched volatilization stages, such as increasing the oxygen concentration, furnace temperature, and gas residence time, significantly improving the volatilization and recovery efficiency of antimony in low-grade raw materials.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal smelting and solid waste resource utilization technology, specifically to a method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology. Background Technology

[0002] With the rapid development of the non-ferrous metal smelting industry, antimony, as an important strategic metal resource, has been widely used in many fields such as electronics, chemicals, and materials. However, antimony ore resources are becoming increasingly depleted, while the amount of antimony-containing waste slag and hazardous solid waste generated during the smelting process is constantly increasing. How to effectively recover antimony and valuable metals from these waste slags and achieve efficient recycling of resources has become an important issue facing the industry.

[0003] Traditional antimony slag metal recovery technologies mostly employ pyrometallurgical or hydrometallurgical processes, but these have many limitations. Pyrometallurgical processes, due to inaccurate furnace temperature control and unstable reducing atmosphere, are prone to problems such as low metal recovery rates, high energy consumption, and severe environmental pollution. This is particularly true for low-grade antimony-containing waste slag, where traditional methods struggle to achieve efficient recovery, resulting in significant resource waste. While hydrometallurgical processes can improve metal recovery rates to some extent, they suffer from drawbacks such as long process flows, difficult wastewater treatment, and high operating costs, limiting their widespread adoption in large-scale industrial applications. Furthermore, traditional technologies suffer from insufficient waste heat recovery and low overall energy efficiency, further increasing production costs and environmental pressure.

[0004] In response to the problems of low recovery rate, high energy consumption, serious environmental pollution and insufficient waste heat recovery in traditional antimony slag metal recovery technologies, an enhanced antimony slag metal recovery method based on oxygen-enriched volatilization technology has emerged. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology. This method can significantly improve the recovery rate of antimony and valuable metals in low-grade antimony-containing waste slag through pretreatment enhancement and process parameter optimization, and broaden the applicable range of raw materials. At the same time, by adopting waste heat cascade utilization and multi-scenario adaptation scheme, it achieves efficient and comprehensive utilization of energy, and reduces production costs and environmental impact.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology, the specific steps of which are as follows:

[0007] S1. Antimony slag pretreatment: Antimony-containing waste slag is mixed with low-sulfur materials and solvents at a mass ratio of (8~10):(1~2):(0.5~1), and processed into granules with a particle size of 5~15mm by a granulator, with the moisture content of the granules controlled to ≤3%;

[0008] S2, Side-blown molten reduction: Add the S1 granules to the side-blown reduction furnace, and control the height of the molten pool in the furnace: 1.6~1.8m before slag feeding and 2.0~2.4m after slag feeding, which is monitored in real time by slag probe rod; adjust the natural gas main flow rate to 250~300m³ / h, the branch pipe pressure to 0.25~0.4MPa, the oxygen enrichment flow rate to 1050~1200m³ / h, the oxygen enrichment concentration to 60%, and maintain the reducing atmosphere for the reduction reaction for 50min±5min. Stop the alloy discharge after the alloy flow rate at the siphon port decreases.

[0009] S3. Heating Pretreatment: After the reduction reaction is completed, the oxygen concentration is increased to 70%, the natural gas and compressed air flow rates are kept constant, and the temperature is increased for 15-20 minutes to raise the furnace temperature to 1150-1180℃. At the same time, the slagging preparation of the fuming furnace is started.

[0010] S4. Oxygen-enriched volatilization enhancement: The molten slag pretreated by heating in S3 is introduced into the oxygen-enriched volatilization furnace through the furnace chute. The temperature in the volatilization furnace is controlled at 1200~1250℃, the oxygen concentration is 65~70%, and the gas residence time is 30~40min, so that the residual antimony oxide and other volatile valuable metals in the slag are converted into gaseous oxides.

[0011] S5. Valuable Metal Collection: The flue gas discharged from the volatile matter furnace recovers heat through a waste heat boiler, and then gaseous oxides are captured by a bag filter to obtain flue gas rich in antimony and lead; after collection, the flue gas undergoes zinc oxide desulfurization treatment to ensure... Emission concentration <50mg / Nm³, meeting emission standards;

[0012] S6. Recycling: The flue dust obtained from bag dust collection is mixed with low-sulfur materials and solvents to form granules, and then returned to the side-blown reduction furnace in S2 for recycling treatment, so as to achieve a balance between flue dust production and sales and stable slag shape.

[0013] Furthermore, the solvent in S1 is a compound system of limestone, iron-silicon-calcium, and quartz sand, wherein the mass ratio of limestone, iron-silicon-calcium, and quartz sand is (3~5):(0.3~0.8):(1~1.5), and the selection of the compound solvent needs to be dynamically adjusted according to the chemical composition of the antimony-containing waste residue: when the antimony residue contains When the content is ≥15%, reduce the proportion of quartz sand to 0.8~1.0 parts and increase the proportion of limestone to 5~6 parts to adjust the acidity and alkalinity of the slag. When the FeO content in the antimony slag is ≥8%, increase the proportion of iron-silicon-calcium to 2~2.5 parts. Utilize the fluxing effect of iron-silicon-calcium to lower the melting point of the slag, reduce the viscosity resistance during the melting process, and ensure the mass transfer efficiency of subsequent reduction and volatilization reactions. The particle size of the compound solvent is controlled at 0.1~3mm, of which particles with a diameter <1mm account for ≥70%. This ensures that the solvent, antimony slag, and low-sulfur materials are mixed evenly during the granulation process, avoiding metal loss due to insufficient local reaction. At the same time, it improves the permeability of the granules during the smelting process and reduces the risk of foam slag formation.

[0014] Furthermore, when the antimony-containing waste residue in S1 is smelting waste residue from brittle lead-antimony ore or hazardous solid waste containing antimony, a differentiated pretreatment scheme is adopted: For smelting waste residue from brittle lead-antimony ore, anthracite is selected as the low-sulfur material. During mixing, the antimony slag is first crushed to a particle size <5mm, and then mixed with the low-sulfur material and solvent for granulation. During the granulation process, 1-2% water glass by mass is added as an auxiliary binder to improve the air permeability of the granules. For hazardous solid waste containing antimony, low-temperature roasting is carried out before pretreatment to remove organic matter from the material. After roasting, the material is cooled to room temperature before mixing and granulation. At the same time, 10-15% sodium carbonate by mass is added to the solvent to enhance the sulfidation precipitation effect of heavy metals. After pretreatment, the composition of the granules is detected by X-ray fluorescence spectroscopy to ensure that the fluctuation range of valuable metals such as Sb, Pb, and Zn is ≤±5%, which provides a guarantee for the stability of parameters in the subsequent smelting process.

[0015] Furthermore, for the low-grade raw material S1 containing antimony waste slag with an antimony content of <5%, a pretreatment enhancement + process parameter optimization adaptation scheme is adopted: In the pretreatment stage, antimony slag is mixed with calcium oxide with a mass fraction of 5~8% and roasted. Through roasting, low-valent antimony is converted into easily volatile antimony trioxide. The roasted product is cooled to room temperature and then mixed with low-sulfur materials and solvent for granulation; In the side-blown reduction stage, the oxygen enrichment concentration is increased to 62~65%, the reduction time is extended to 60~70 min, and the coal feeding rate is increased to 2.5~3.0 t / h. The reduction reaction intensity is enhanced; during the oxygen-enriched volatilization stage, the furnace temperature is increased to 1250~1300℃, the oxygen concentration is increased to 70~75%, and the gas residence time is extended to 40~50min to promote the full volatilization of antimony in low-grade raw materials; at the same time, 2~3% by mass of iron powder is added as a reducing agent in the side-blown reduction furnace to improve the reduction efficiency of low-valent antimony; through the above optimization, the antimony recovery rate of low-grade antimony-containing waste residue is ≥95%, reaching the recovery level of high-grade raw materials, significantly expanding the raw material application scope of this invention.

[0016] Furthermore, the molten pool height in the side-blown reduction furnace in S2 adopts a dual-monitoring + dynamic adjustment mechanism. In addition to real-time measurement by the slag probe, it is simultaneously monitored online by three sets of infrared liquid level sensors installed on the side wall of the furnace body. The sensor data is linked with the DCS control system in real time. When the rate of increase of the molten pool height during slag feeding exceeds 0.02m / min, the feed rate of the granular material is automatically reduced by 10-20%, and the flow rate of the natural gas main is increased by 5-10%. This enhances the combustion intensity and improves the reaction rate of the molten pool, preventing the molten pool height from exceeding the upper limit. To prevent flue gas overflow caused by excessive reduction, when the height of the molten pool after slag feeding is less than 2.0m, while maintaining the oxygen enrichment concentration, the oxygen enrichment flow rate should be increased to 1200~1300m³ / h, and the coal feeding rate should be accelerated to 2.5~3.0t / h to shorten the reduction reaction start-up time. During the reduction stage, the antimony oxide content in the slag should be sampled and analyzed every 10 minutes using a slag probe. When the antimony oxide content is <2%, the alloy discharge should be stopped 5~8 minutes in advance to avoid energy waste caused by excessive reduction and to ensure the purity and recovery rate of the lead-antimony alloy.

[0017] Furthermore, the gas flow rate and pressure in the oxygen-enriched volatilization furnace in S4 employ a coordinated control strategy. The gas flow rate is dynamically adjusted based on the feed rate of molten slag in the volatilization furnace: when the feed rate of a single furnace is 5~8t, the gas flow rate is controlled at 1000~1100 m³ / h; when the feed rate is 8~12t, the gas flow rate is adjusted to 1100~1200 m³ / h, while the branch pipe pressure is simultaneously increased to 0.35~0.4MPa, ensuring that the gas penetration depth in the molten pool is ≥0.8m, forming a uniform bubble stirring effect. Promote the separation of volatile valuable metals from the slag phase; three sets of temperature monitoring points are set in the volatilization furnace, located at the top, middle and bottom of the furnace body respectively. When the bottom temperature is lower than 1200℃, the temperature is maintained by increasing the amount of natural gas supplementary combustion; the gas residence time is precisely controlled by adjusting the angle of the flue gas guide plate at the tail of the furnace body. The angle of the guide plate can be adjusted within the range of 30~60°. For every 10° increase in angle, the gas residence time is extended by 3~5 minutes to ensure that gaseous oxides are fully generated and avoid metal residue due to insufficient residence time.

[0018] Furthermore, the valuable metal collection in S5 adopts a graded collection + precise separation system. The bag filter uses PTFE membrane filter media, with the filtration velocity controlled at 0.8~1.2m / min and the filter media surface temperature maintained at 120~150℃ to prevent gaseous oxides from condensing and clogging the filter media. The mixed dust obtained after bag collection is further separated by an air classifier. The airflow velocity in the classifier is controlled at 15~25m / s, and antimony oxide and lead oxide are collected separately according to the particle density difference. The coarse particles are rich in lead oxide and are sold directly as raw materials for lead smelting; the fine particles are rich in antimony oxide and are returned to the side-blown reduction furnace for recycling. During the desulfurization process, the particle size of the zinc oxide desulfurizing agent is controlled at 0.5~1mm, the gas-liquid contact time in the desulfurization tower is ≥8s, and the concentration of the desulfurizing agent slurry is maintained at 15~20%. The concentration of the desulfurizing agent is monitored online in the flue gas. Adjust the slurry spraying volume in real time according to the concentration. When the concentration is >40 mg / Nm³, the spray volume should be increased by 20-30% to ensure a desulfurization efficiency ≥99% and desulfurization products. After concentration, crystallization, and drying, the purity is ≥98%, and it is recycled as an industrial-grade zinc sulfate product.

[0019] Furthermore, the waste heat recovery in S5 adopts a tiered utilization + multi-scenario adaptation scheme. The 3.8MPa saturated steam produced by the waste heat boiler is first fed into a back-pressure steam turbine for power generation. The exhaust steam from the steam turbine is used as low-pressure steam for the drying process in the granulation workshop and for heating the office area. During power generation, the power generation efficiency of the steam turbine is maintained at 30-35% by adjusting the steam intake. The feedwater temperature of the waste heat boiler is preheated to 100-120℃ by the economizer to improve the boiler's thermal efficiency. When the external heating demand is insufficient, the excess steam is condensed into water by the condenser, treated by the deaerator, and returned to the waste heat boiler for recycling, with a water resource recovery rate of ≥95%. The waste heat recovery system is linked with the DCS control system, and the operating parameters are adjusted in real time according to the steam output, power generation load, and heating demand to ensure that the waste heat utilization rate is ≥90%. Compared with the traditional single power generation or heating mode, the comprehensive energy utilization efficiency is improved by 20-25%.

[0020] Furthermore, the mixing ratio of recycled flue dust and new material in S6 adopts a dynamic optimization mechanism. During the first cycle, the mass ratio of flue dust to mixed raw materials is 10-15%. As the number of cycles increases, the ratio gradually increases to 20-25%, with a maximum of no more than 30%, to avoid the accumulation of impurities in the flue dust leading to slag deterioration. During the granulation process, a binder with a mass fraction of 0.3-0.5% is added, which is a mixture of starch and bentonite in a mass ratio of 2:1, to improve the compressive strength and thermal stability of the granules and prevent the granules from breaking and generating dust in the high-temperature furnace. After granulation, the granules are dried using a microwave drying device with microwave power controlled at 30-50kW and drying time of 5-8 minutes to ensure that the moisture content of the granules is ≤2%. Compared with traditional hot air drying, the drying efficiency is increased by more than 40%, while reducing heat loss. The composition of the circulating flue dust is tested every 5 cycles. When the impurity content is ≥0.5%, part of the flue dust is sent to a bottom-blown furnace for oxidation and impurity removal treatment to ensure the stable operation of the circulation system.

[0021] Furthermore, the safety control of the entire process adopts a multi-level monitoring + intelligent early warning system. In addition to the temperature detection points of each furnace, dual flow meters and temperature sensors are installed on the water jacket inlet and outlet water pipes of the side-blown reduction furnace. When the difference between the two data exceeds 10%, the DCS system automatically issues an early warning and cuts off the feed, while simultaneously activating the backup cooling water circuit. The furnace pressure of the bottom-blown furnace, reduction furnace, and volatilization furnace is monitored in real time by pressure transmitters, and the pressure is controlled within -50~+50Pa. When the pressure exceeds the range, the furnace door opening and induced draft fan frequency are automatically adjusted to ensure stable furnace pressure. A dust concentration monitor is installed in the granulation workshop. When the dust concentration is >10mg / m³, the spray dust suppression system is automatically activated. A pH online monitor and a heavy metal ion concentration detector are installed in the heavy metal waste acid treatment area. The pH is controlled between 2 and 3. When the heavy metal ion concentration is >10mg / L, the amount of sulfurizing agent added is automatically increased to prevent hazardous waste leakage. All monitoring data is stored in real time to a cloud server with a storage period of ≥3 years, facilitating production traceability and process optimization.

[0022] Compared with existing technologies, this method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology has the following advantages:

[0023] I. This method achieves efficient recovery of antimony from low-grade raw materials, particularly those with antimony content below 5%, through a combination of enhanced pretreatment and optimized process parameters. In the pretreatment stage, antimony slag is mixed with calcium oxide and roasted to convert low-valent antimony into volatile antimony trioxide. Simultaneously, process parameters are adjusted during the side-blown reduction and oxygen-enriched volatilization stages, such as increasing oxygen concentration, furnace temperature, and gas residence time, significantly improving the volatilization and recovery efficiency of antimony from low-grade raw materials. Experimental results show that the antimony recovery rate from low-grade antimony-containing waste slag can reach over 95%, achieving the recovery level of high-grade raw materials. This significantly broadens the applicable range of raw materials and reduces production costs.

[0024] Second, this method adopts a cascaded utilization and multi-scenario adaptation scheme for waste heat recovery. Saturated steam is generated by a waste heat boiler and first used for power generation by a back-pressure steam turbine. The exhaust steam from the steam turbine is then used as low-pressure steam for the drying process in the granulation workshop and for heating in the office area, realizing the cascaded utilization of energy. At the same time, the waste heat recovery system is linked with the DCS control system, and the operating parameters are adjusted in real time according to steam output, power generation load and heating demand, ensuring that the waste heat utilization rate reaches more than 90%. Compared with the traditional single power generation or heating mode, the comprehensive energy utilization efficiency of this method is improved by 20% to 25%, significantly reducing energy consumption and operating costs, and improving overall economic benefits.

[0025] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0027] Figure 1 This is a flow chart of a method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology.

[0028] Figure 2 A differentiated flow chart of antimony slag pretreatment for a metal-enhanced recovery method based on oxygen-enriched volatilization technology;

[0029] Figure 3 This is a full-process safety-energy synergistic flow diagram of a metal enhancement recovery method for antimony slag based on oxygen-enriched volatilization technology. Detailed Implementation

[0030] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0031] Example 1

[0032] Smelting waste from brittle lead-antimony ore was selected as the antimony-containing raw material. The antimony-containing waste was mixed with low-sulfur anthracite and a compound solvent at a mass ratio of 8:1:0.5. The compound solvent consisted of limestone, iron-silicon-calcium, and quartz sand in a mass ratio of 3:1:1. The solvent particle size was controlled between 0.1 and 3 mm, with particles <1 mm accounting for ≥70%. The antimony slag was first crushed to a particle size <5 mm, and then 1% water glass was added as an auxiliary binder. Both were then fed into a granulator to process into granules with a particle size of 5-15 mm, with the moisture content of the granules strictly controlled to ≤3%. After pretreatment, the composition of the granules was analyzed by X-ray fluorescence spectroscopy to ensure that they met the requirements of subsequent processes.

[0033] The granules prepared by S1 were added to a side-blown reduction furnace. A dual-monitoring + dynamic adjustment mechanism was used to control the molten pool height. Before slag feeding, the molten pool height was maintained at 1.6m, and after slag feeding, it was controlled at 2.0m. Real-time monitoring was conducted using a slag probe, while simultaneously using three sets of infrared liquid level sensors installed on the furnace sidewall for online monitoring. The sensor data was linked in real-time with the DCS control system. The natural gas main flow rate was adjusted to 250m³ / h, the branch pipe pressure to 0.25MPa, the oxygen enrichment flow rate to 1050m³ / h, and the oxygen enrichment concentration to 60%, maintaining a reducing atmosphere for 50 minutes of reduction reaction. During the reduction stage, antimony oxide content in the slag was sampled and analyzed every 10 minutes using a slag probe. When the antimony oxide content was detected to be <2%, alloy discharge was stopped 5 minutes in advance. Throughout the process, if the rate of increase in molten pool height exceeded 0.02m / min during slag feeding, the DCS system automatically reduced the granule feeding rate by 10% and increased the natural gas main flow rate by 5%.

[0034] After the reduction reaction is completed, the oxygen concentration is increased to 70%, the natural gas and compressed air flow rates are kept constant, and the temperature is continuously increased for 15 minutes to raise the furnace temperature to 1150℃. At the same time, the slagging preparation work of the fuming furnace is started to ensure the smooth connection of the subsequent oxygen-enriched volatilization process.

[0035] The pre-treated molten slag from S3 is introduced into the oxygen-enriched volatilization furnace via a chute between furnaces, with a single furnace feed rate of 5t. According to a coordinated control strategy, the gas flow rate is controlled at 1000 m³ / h, and the branch pipe pressure is simultaneously increased to 0.35 MPa. The temperature inside the volatilization furnace is controlled at 1200℃, and the oxygen concentration is 65%. By adjusting the angle of the flue gas guide plate at the tail of the furnace to 30°, the gas residence time reaches 30 minutes. Three sets of temperature monitoring points are set up inside the volatilization furnace, located at the top, middle, and bottom of the molten pool, respectively, to monitor temperature changes in real time. If the bottom temperature is lower than 1200℃, the temperature is maintained by increasing the amount of natural gas supplementary combustion, ensuring that the residual antimony oxide and other volatile valuable metals in the slag are fully converted into gaseous oxides.

[0036] The flue gas discharged from the volatile organic compound (VOC) first enters a waste heat boiler to recover heat, employing a cascade utilization and multi-scenario adaptation scheme. The 3.8MPa saturated steam produced by the waste heat boiler is fed into a back-pressure steam turbine for power generation. The turbine's power generation efficiency is maintained at 30% by adjusting the steam intake. The turbine exhaust steam is used as low-pressure steam for the drying process in the granulation workshop and for heating the office area. The feedwater of the waste heat boiler is preheated to 100℃ by an economizer. When external heating demand is insufficient, excess steam is condensed into water by a condenser, treated by a deaerator, and returned to the waste heat boiler for recycling. The water resource recovery rate is ≥95%. The waste heat recovery system is linked with the DCS control system to adjust operating parameters in real time. The cooled flue gas enters a bag filter dust collector, which uses PTFE membrane filter media. The filtration velocity is controlled at 0.8m / min, and the filter media surface temperature is maintained at 120℃ to capture gaseous oxides, obtaining mixed dust rich in antimony and lead. The mixed flue gas undergoes secondary separation via an air classifier. The airflow velocity within the classifier is controlled at 15 m / s. Antimony oxides and lead oxides are collected separately based on particle density differences. Fine particles rich in antimony oxides are used for subsequent recycling. After collection, the flue gas enters a desulfurization tower, where zinc oxide desulfurization is performed. The particle size of the zinc oxide desulfurizing agent is controlled at 0.5 mm. The gas-liquid contact time within the desulfurization tower is ≥8 s, and the desulfurizing agent slurry concentration is maintained at 15%. The concentration of the desulfurizing agent slurry is monitored online. Adjust the slurry spraying volume in real time according to the concentration. When the concentration is >40 mg / Nm³, the spray volume increases by 20%.

[0037] A dynamic optimization mechanism was used to determine the mixing ratio of recycled flue dust and virgin material. During the initial cycle, fine particulate flue dust rich in antimony oxides obtained from baghouse dust collection accounted for 10% of the mixed raw material by mass. This was mixed with low-sulfur materials and solvents before granulation. A binder with a mass fraction of 0.3% was added during granulation. After granulation, the material was dried using a microwave drying device with a microwave power controlled at 30kW and a drying time of 5 minutes to minimize heat loss. The dried granules were returned to the side-blown reduction furnace in S2 for recycling. The composition of the recycled flue dust was analyzed every 5 cycles. When the impurity content was ≥0.5%, a portion of the flue dust was sent to a bottom-blown furnace for oxidation and impurity removal. As the number of cycles increased, the flue dust mixing ratio gradually increased to 20%, with a maximum not exceeding 30%.

[0038] Example 2

[0039] Antimony-containing hazardous solid waste with an antimony content of <5% was selected as raw material, and a combination of enhanced pretreatment and optimized process parameters was adopted. First, the antimony-containing hazardous solid waste was subjected to low-temperature roasting to remove organic matter. After roasting, the material was cooled to room temperature. The cooled material was mixed with low-sulfur materials and a compound solvent at a mass ratio of 10:2:1. Simultaneously, 10% sodium carbonate was added to the solvent to enhance the sulfidation precipitation effect of heavy metals. The compound solvent consisted of limestone, iron-silicon-calcium, and quartz sand in a mass ratio of 5:2:1.5. The solvent particle size was controlled at 0.1~3mm, with particles <1mm accounting for ≥70%. In the pretreatment stage, the above mixture was also roasted with 5% calcium oxide. Roasting converted low-valent antimony into volatile antimony trioxide. After cooling to room temperature, the roasted product was fed into a granulator to process into granules with a particle size of 5~15mm, controlling the moisture content of the granules to ≤3%. After pretreatment, the composition of the granules is detected by X-ray fluorescence spectroscopy to ensure that they meet the requirements of subsequent processes.

[0040] The granules prepared by S1 were added to the side-blown reduction furnace. A dual-monitoring + dynamic adjustment mechanism was used to control the molten pool height. Before slag feeding, the molten pool height was maintained at 1.8m, and after slag feeding, it was controlled at 2.4m. Real-time monitoring was achieved through a combination of slag probes and online monitoring by three sets of infrared liquid level sensors, with data linked in real-time with the DCS control system. The natural gas main flow rate was adjusted to 300 m³ / h, the branch pipe pressure to 0.4 MPa, and the oxygen enrichment flow rate to 1300 m³ / h, increasing the oxygen enrichment concentration to 62%. 2% iron powder (by mass) was added to the side-blown reduction furnace as a reducing agent, and the coal feeding rate was increased to 2.5 t / h. The reducing atmosphere was maintained for 60 minutes for the reduction reaction. During the reduction stage, antimony oxide content in the slag was analyzed every 10 minutes using slag probes. When the antimony oxide content was <2%, alloy discharge was stopped 8 minutes earlier. If the molten pool height was below 2.0m after slag feeding, the current oxygen enrichment flow rate was maintained while keeping the oxygen enrichment concentration constant, and the coal feeding rate was increased to 2.5 t / h to shorten the reduction reaction start-up time.

[0041] After the reduction reaction is completed, the oxygen concentration is increased to 70%, the natural gas and compressed air flow rates are kept constant, and the temperature is continuously increased for 20 minutes to raise the furnace temperature to 1180℃. At the same time, the slagging preparation work of the fuming furnace is started to prepare for the introduction of molten slag into the oxygen-enriched volatilization furnace.

[0042] The pre-treated molten slag from S3 is introduced into the oxygen-enriched volatilization furnace via a chute between furnaces, with a single furnace feed rate of 12t. According to the coordinated control strategy, the gas flow rate is adjusted to 1200 m³ / h, and the branch pipe pressure is simultaneously increased to 0.4 MPa. The temperature inside the volatilization furnace is controlled at 1300℃, and the oxygen concentration is increased to 75%. By adjusting the angle of the flue gas guide plate at the tail of the furnace to 60°, the gas residence time is extended to 50 minutes. Three sets of temperature monitoring points inside the volatilization furnace monitor the temperature in real time to ensure that the bottom temperature is not lower than 1200℃, guaranteeing that the residual antimony oxide and other volatile valuable metals in the slag are fully converted into gaseous oxides.

[0043] The flue gas discharged from the volatile organic compound (VOC) furnace enters a waste heat boiler for heat recovery. A tiered utilization and multi-scenario adaptation scheme is adopted. The 3.8MPa saturated steam produced by the waste heat boiler is fed into a back-pressure steam turbine for power generation, maintaining a power generation efficiency of 35%. The turbine exhaust steam is used for drying in the granulation workshop and for office heating. Feedwater is preheated to 120℃ by an economizer. Excess steam is condensed, deoxygenated, and returned to the waste heat boiler for circulation, achieving a water resource recovery rate of ≥95%. After waste heat recovery, the flue gas enters a bag filter dust collector. This device uses PTFE membrane filter media, with the filtration velocity controlled at 1.2m / min and the filter media surface temperature maintained at 150℃, collecting mixed dust. The mixed dust undergoes secondary separation through an air classifier, with the airflow velocity controlled at 25m / s, achieving the separate collection of antimony oxides and lead oxides. Fine particles rich in antimony oxides are used for recycling. In subsequent desulfurization treatment, the particle size of zinc oxide desulfurizing agent is controlled at 1mm, the gas-liquid contact time in the desulfurization tower is ≥8s, the concentration of desulfurizing agent slurry is maintained at 20%, and the flue gas concentration is monitored online. Concentration, when When the concentration is >40 mg / Nm³, the spray volume increases by 30%.

[0044] A dynamic optimization mechanism was used to determine the circulation ratio. In the first circulation, fine particulate matter rich in antimony oxide accounted for 15% of the mass of the mixed raw materials. This was mixed with low-sulfur materials and solvents for granulation, with a binder of 0.5% by mass added during the granulation process. After granulation, the material was processed by microwave drying equipment with microwave power controlled at 50kW and drying time at 8 minutes to reduce heat loss. The dried granules were returned to the side-blown reduction furnace in S2 for circulation. As the number of circulations increased, the proportion of particulate matter mixed with the material gradually increased to 25%, with a maximum of no more than 30%. The composition of the circulating particulate matter was analyzed every 5 circulations. When the impurity content was ≥0.5%, a portion of the particulate matter was sent to the bottom-blown furnace for oxidation and impurity removal treatment.

[0045] The entire process employs a multi-level monitoring and intelligent early warning system. The water jacket inlet and outlet pipes of the side-blown reduction furnace are equipped with dual flow meters and temperature sensors. When the difference between the two data points exceeds 10%, the DCS system automatically issues an early warning and cuts off the feed, activating the backup cooling water circuit. The pressure of each furnace body is monitored in real time by a pressure transmitter and controlled within -50 to +50 Pa. When the pressure exceeds the range, the furnace door opening and induced draft fan frequency are automatically adjusted. The dust concentration monitor in the granulation workshop monitors in real time. When the dust concentration is >10 mg / m³, the spray dust suppression system is automatically activated. The area for treating waste acid containing heavy metals is equipped with an online pH monitor and a heavy metal ion concentration detector. The pH is controlled between 2 and 3. When the heavy metal ion concentration is >10 mg / L, the amount of sulfurizing agent added is automatically increased. All monitoring data is stored in real time on a cloud server.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for enhanced metal recovery from antimony slag based on oxygen-enriched volatilization technology, characterized in that, The specific steps of this method are as follows: S1. Antimony slag pretreatment: Antimony-containing waste slag is mixed with low-sulfur materials and solvent at a mass ratio of (8~10):(1~2):(0.5~1), and processed into granules with a particle size of 5~15mm by a granulator, controlling the moisture content of the granules to ≤3%; the solvent is a compound system of limestone, iron-silicon-calcium and quartz sand, wherein the mass ratio of limestone, iron-silicon-calcium and quartz sand is (3~5):(0.3~0.8):(1~1.5); when the antimony-containing waste slag is smelting waste slag of brittle sulfur lead-antimony ore or antimony-containing hazardous solid waste, a differentiated pretreatment scheme is adopted: for brittle sulfur lead For antimony smelting waste, anthracite is selected as the low-sulfur material. During mixing, the antimony slag is first crushed to a particle size of <5mm, and then mixed with the low-sulfur material and solvent for granulation. During the granulation process, 1-2% water glass is added as an auxiliary binder. For antimony-containing hazardous solid waste, low-temperature roasting is performed before pretreatment to remove organic matter from the material. After roasting, the material is cooled to room temperature before mixing and granulation. At the same time, 10-15% sodium carbonate is added to the solvent to enhance the sulfidation precipitation effect of heavy metals. After pretreatment, the composition of the granules is detected by X-ray fluorescence spectroscopy. S2, Side-blown molten reduction: Add the S1 granules to the side-blown reduction furnace, controlling the height of the molten pool inside the furnace: 1.6~1.8m before slag feeding and 2.0~2.4m after slag feeding, monitored in real time using a slag probe; adjust the natural gas main flow rate to 250~300m³ / h. 3 / h, branch pipe pressure 0.25~0.4MPa, oxygen enrichment flow rate 1050~1200m³ / h 3 / h, oxygen concentration 60%, maintain the reducing atmosphere for 50min±5min, and stop alloy discharge after the alloy flow rate at the siphon port decreases; S3. Heating Pretreatment: After the reduction reaction is completed, the oxygen concentration is increased to 70%, the natural gas and compressed air flow rates are kept constant, and the temperature is increased for 15-20 minutes to raise the furnace temperature to 1150-1180℃. At the same time, the slagging preparation of the fuming furnace is started. S4. Oxygen-enriched volatilization enhancement: The molten slag pretreated by heating in S3 is introduced into the oxygen-enriched volatilization furnace through the furnace chute. The temperature in the volatilization furnace is controlled at 1200~1250℃, the oxygen concentration is 65~70%, and the gas residence time is 30~40min, so that the residual antimony oxide and other volatile valuable metals in the slag are converted into gaseous oxides. S5. Collection of valuable metals: The flue gas discharged from the volatilization furnace recovers heat through a waste heat boiler, and then gaseous oxides are captured by a bag filter dust collector to obtain flue dust rich in antimony and lead. The captured flue gas is then treated with zinc oxide desulfurization. S6. Recycling: The flue dust obtained from baghouse dust collection is mixed with low-sulfur materials and solvents, granulated, and returned to the side-blown reduction furnace in S2 for recycling. The mixing ratio of flue dust and new materials adopts a dynamic optimization mechanism. During the first cycle, the mass ratio of flue dust to mixed raw materials is 10-15%. As the number of cycles increases, the ratio gradually increases to 20-25%. During the recycling granulation process, a binder with a mass fraction of 0.3-0.5% is added. After granulation, the flue dust is dried using a microwave drying device with microwave power controlled at 30-50kW and drying time of 5-8 minutes, while reducing heat loss. The composition of the recycled flue dust is tested every 5 cycles. When the impurity content is ≥0.5%, part of the flue dust is sent to the bottom-blown furnace for oxidation and impurity removal.

2. The method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology according to claim 1, characterized in that, The low-grade raw material S1, containing antimony waste slag with an antimony content of <5%, adopts an adaptation scheme of pretreatment enhancement and process parameter optimization: In the pretreatment stage, antimony slag is mixed with calcium oxide with a mass fraction of 5-8% and roasted. Through roasting, low-valent antimony is converted into easily volatile antimony trioxide. The roasted product is cooled to room temperature and then mixed with low-sulfur materials and solvent for granulation. In the side-blown reduction stage, the oxygen concentration is increased to 62-65%, the reduction time is extended to 60-70 min, and the coal feeding rate is increased to 2.5-3.0 t / h to enhance the reduction reaction intensity. In the oxygen-enriched volatilization stage, the furnace temperature is increased to 1250-1300℃, the oxygen concentration is increased to 70-75%, and the gas residence time is extended to 40-50 min. At the same time, iron powder with a mass fraction of 2-3% is added as a reducing agent in the side-blown reduction furnace.

3. The method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology according to claim 1, characterized in that, The molten pool height in the S2 side-blown reduction furnace employs a dual-monitoring and dynamic adjustment mechanism. In addition to real-time measurement by the slag probe, it is simultaneously monitored online by three sets of infrared liquid level sensors installed on the furnace sidewall. The sensor data is linked in real-time with the DCS control system. When the molten pool height rises at a rate exceeding 0.02 m / min during slag feeding, the feed rate of the granular material is automatically reduced by 10-20%, and the flow rate of the main natural gas pipeline is increased by 5-10%, thereby enhancing the combustion intensity and improving the molten pool reaction rate. When the molten pool height falls below 2.0 m after slag feeding, the oxygen enrichment flow rate is increased to 1200-1300 m³ / min while maintaining a constant oxygen enrichment concentration. 3 At the same time, the coal feeding rate is increased to 2.5~3.0t / h to shorten the start-up time of the reduction reaction; during the reduction stage, the antimony oxide content in the slag is analyzed by taking a sample every 10 minutes through the slag probe. When the antimony oxide content is <2%, the alloy discharge is stopped 5~8 minutes in advance.

4. The method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology according to claim 1, characterized in that, The gas flow rate and pressure in the oxygen-enriched volatilization furnace in S4 adopt a coordinated control strategy. The gas flow rate is dynamically adjusted according to the feed rate of molten slag in the volatilization furnace: when the feed rate of a single furnace is 5~8t, the gas flow rate is controlled at 1000~1100m³. 3 / h; when the feed rate is 8~12t, the gas flow rate is adjusted to 1100~1200m³ / h. 3 / h, while the branch pipe pressure is simultaneously increased to 0.35~0.4MPa; three sets of temperature monitoring points are set in the volatilization furnace, located at the top, middle and bottom of the furnace body respectively. When the bottom temperature is lower than 1200℃, the temperature is maintained by increasing the amount of natural gas supplementary combustion; the gas residence time is precisely controlled by adjusting the angle of the flue gas guide plate at the tail of the furnace body. The angle of the guide plate can be adjusted within the range of 30~60°. For every 10° increase in angle, the gas residence time is extended by 3~5 minutes.

5. The method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology according to claim 1, characterized in that, The valuable metal collection in S5 employs a graded collection and precise separation system. The bag filter uses PTFE membrane filter media, with the filtration velocity controlled at 0.8~1.2 m / min and the filter media surface temperature maintained at 120~150℃. The mixed dust obtained after bag collection undergoes secondary separation via an air classifier. The airflow velocity within the classifier is controlled at 15~25 m / s, achieving graded collection of antimony oxides and lead oxides based on particle density differences. Fine particles rich in antimony oxides are returned to the side-blown reduction furnace for recycling. During desulfurization, the particle size of the zinc oxide desulfurizing agent is controlled at 0.5~1 mm, the gas-liquid contact time in the desulfurization tower is ≥8 s, and the desulfurizing agent slurry concentration is maintained at 15~20%. The slurry spraying volume is adjusted in real time by monitoring the SO2 concentration in the flue gas online. When the SO2 concentration is >40 mg / Nm³, the spraying volume is adjusted accordingly. 3 At this time, the spray volume increases by 20-30%.

6. The method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology according to claim 1, characterized in that, The waste heat recovery in S5 adopts a tiered utilization and multi-scenario adaptation scheme. The 3.8MPa saturated steam produced by the waste heat boiler is first fed into a back-pressure steam turbine for power generation. The exhaust steam from the steam turbine is used as low-pressure steam for the drying process in the granulation workshop and for heating the office area. During power generation, the power generation efficiency of the steam turbine is maintained at 30~35% by adjusting the steam intake. The feedwater temperature of the waste heat boiler is preheated to 100~120℃ by the economizer. When the external heating demand is insufficient, the excess steam is condensed into water by the condenser, treated by the deaerator, and returned to the waste heat boiler for recycling. The water resource recovery rate is ≥95%. The waste heat recovery system is linked with the DCS control system and adjusts the operating parameters in real time according to the steam output, power generation load, and heating demand.

7. The method for enhanced metal recovery of antimony slag based on oxygen-enriched volatilization technology according to claim 1, characterized in that, The entire process safety control employs a multi-level monitoring and intelligent early warning system. In addition to temperature detection points in each furnace, dual flow meters and temperature sensors are installed on the water jacket inlet and outlet pipes of the side-blown reduction furnace. When the difference between the two data points exceeds 10%, the DCS system automatically issues an early warning and cuts off the feed, while simultaneously activating the backup cooling water circuit. The furnace pressure of the bottom-blown furnace, reduction furnace, and volatilization furnace is monitored in real time via pressure transmitters, with pressure controlled within -50 to +50 Pa. When the pressure exceeds this range, the furnace door opening and induced draft fan frequency are automatically adjusted. A dust concentration monitor is installed in the granulation workshop; when the dust concentration > 10 mg / m³... 3 When the dust is exposed to heavy metals, the spray dust suppression system is automatically activated. The area where the waste acid containing heavy metals is treated is equipped with an online pH monitor and a heavy metal ion concentration detector. The pH is controlled at 2-3. When the heavy metal ion concentration is >10mg / L, the amount of sulfurizing agent added is automatically increased. All monitoring data is stored in real time to the cloud server.

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