Metallurgical solid waste all-component collaborative recovery and high-value utilization method

Abstract

The invention discloses a metallurgical solid waste all-component collaborative recovery and high-value utilization method, and belongs to the technical field of metallurgical resource recycling and green metallurgy. According to the method, blast furnace gas sludge, iron-manganese slag and vanadium extraction converter sludge are synergistically blended, and after briquetting and drying, reduction smelting is carried out in an inert atmosphere. Reducing the iron into molten iron; volatile metals such as zinc, indium and gallium are evaporated and enter flue gas, and gallium-indium alloy, crude zinc and residual ash are recovered in a graded manner through a multi-stage condensation system; the slag is subjected to acid leaching to enrich scandium, the leaching liquid is separated to extract vanadium, manganese and scandium, and the leaching slag is used for preparing low-carbon cement. According to the method, all-component collaborative recovery of valuable metals in various metallurgical solid wastes and building material utilization of residual solid wastes are realized, and the method has the advantages of high resource efficiency and environmental friendliness.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical resource recycling and green metallurgy technology, specifically relating to a method for the synergistic recovery and high-value utilization of all components of metallurgical solid waste. Background Technology

[0002] The smelting and production process of Panzhihua vanadium-titanium magnetite mines generates a large amount of solid waste, such as iron-manganese slag, vanadium-extraction converter sludge, and blast furnace gas sludge. These solid wastes not only occupy a large amount of land but also contain various valuable metals such as iron, zinc, manganese, indium, gallium, and scandium. Improper disposal can easily lead to environmental risks such as heavy metal pollution. Current methods for treating these metallurgical solid wastes have the following main shortcomings.

[0003] Pyrometallurgical processes: While traditional reduction smelting can recover iron, it struggles to effectively enrich and recover volatile metals such as zinc, indium, and gallium, and generally suffers from high energy consumption and low recovery rates. Hydrometallurgical processes: Although wet leaching can extract some valuable metals, it typically involves long processes, high costs, and struggles to achieve synergistic and efficient recovery of all valuable components. Difficulty in separating complex components and low efficiency in removing associated harmful elements are common problems. Existing methods mostly target single solid wastes or single target metals, lacking a systematic solution for the synergistic treatment of multiple solid wastes to achieve full component recovery, resulting in low resource utilization efficiency and poor economics. Secondary slag phases after valuable element extraction, if not properly utilized, will still form new solid waste. While there has been some progress in the application of metallurgical slag in the building materials field, such as the preparation of low-carbon multi-component cementitious materials, or its use as thermal insulation fillers and wear-resistant materials through steel slag modification and gas quenching technology, breakthroughs are still needed to achieve large-scale, high-value utilization.

[0004] Therefore, there is an urgent need to study a new method for treating metallurgical solid waste that can synergistically recover multiple valuable metals, achieve high-value utilization of all components, and is economical and environmentally friendly. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the existing recycling processes for metallurgical solid wastes such as iron and manganese slag are complex and inefficient.

[0006] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows.

[0007] In a first aspect, the present invention provides a method for the synergistic recovery and high-value utilization of all components of metallurgical solid waste, wherein the metallurgical solid waste is blast furnace gas sludge, iron-manganese slag, and vanadium extraction converter sludge, and the method includes the following steps: S1. Blast furnace gas sludge, iron-manganese slag and vanadium-extraction converter sludge are crushed, mixed and then pulverized to obtain a mixture; S2. Mix the mixture, flux, reducing agent, binder and water evenly, form into pellets and dry to obtain pellet material; S3. Pelletized materials are reduced and smelted in an inert atmosphere at 800~1500℃ to obtain molten iron alloy, volatile metal vapor and slag; S3-1. The volatiles are collected separately as gallium-indium alloy, liquid crude zinc, and residual ash through multi-stage condensation; S3-2. The slag is wet leached to obtain a leachate containing vanadium, manganese and scandium and a leaching residue containing calcium and silicon. The leachate is solvent extracted to separate and recover vanadium, manganese and scandium.

[0008] In step S1 above, the main chemical components of the blast furnace gas sludge, by mass percentage, include: C 15.0~18.5%, Fe 34.0~39.0%, Zn 10.0~16.5%, and In 0.10~0.2%.

[0009] In step S1 above, the main chemical components of the iron-manganese slag, by mass percentage, include: Fe 35.0~39.0%, Mn 3.0~4.0%, Mg 3.0~4.0%, Ca 1.0~3.0%, and Sc 0.5~0.7%.

[0010] In step S1 above, the main chemical components of the vanadium extraction converter sludge, by mass percentage, include: Fe 61.0~67.0%, Zn 2.0~4.0%, and Ga 0.2~0.7%.

[0011] In step S1 above, the mass ratio of the blast furnace gas sludge, iron-manganese slag and vanadium-extraction converter sludge is 1:0.2~1:0.4~1.

[0012] In step S1 above, the mixed material is crushed to below 100 mesh.

[0013] In step S2 above, the flux is alumina or silicon dioxide, and the amount of flux added is 3 to 7% of the mass of the mixture.

[0014] In step S2 above, the reducing agent is coke or pulverized coal, and the amount of reducing agent added is 10-30% of the mass of the mixture.

[0015] In step S2 above, the binder is at least one of bentonite, lime, and water glass, and the amount of binder added is 0.5 to 1.5% of the mass of the mixture.

[0016] In step S2 above, the amount of water added is 5-15% of the mass of the mixture.

[0017] In step S2 above, the particle size of the ore pellets is 8~16mm.

[0018] In step S3 above, the reduction smelting time is 1 to 4 hours.

[0019] In step S3-1 above, the multi-stage condensation specifically involves: the first stage condensate temperature being 80~100℃, recovering gallium-indium alloy; the second stage condensate temperature being 50~80℃, recovering liquid crude zinc; and the third stage condensate temperature being 5~25℃, recovering residual ash.

[0020] In step S3-2 above, the slag is wet-leached with an acidic solution; the acidic solution is a sulfuric acid solution, hydrochloric acid solution, phosphoric acid solution or nitric acid solution, with a concentration of 0.5~5 mol / L; the solid-liquid ratio of the slag to the acidic solution is 1g:3~10mL, the leaching time is 60~150min, and the leaching temperature is 25~90℃.

[0021] In step S3-2 above, the solvent extraction specifically includes the following steps: S3-2-1. Using a vanadium-, scandium-, and manganese-containing leachate as the aqueous phase, an organic phase containing an extractant, a modifier TBP, and a diluent is used for extraction to obtain a vanadium-loaded organic phase and a scandium- and manganese solution. The organic phase is back-extracted with sulfuric acid solution to obtain vanadium. S3-2-2. Using a scandium and manganese solution as the aqueous phase, an organic phase containing an extractant, a modifier TBP, and a diluent is used for extraction to obtain an organic phase loaded with scandium and manganese. The organic phase is first back-extracted with sulfuric acid solution to obtain manganese, and then back-extracted with sodium hydroxide solution to obtain scandium. The extractant is either P204 or P507.

[0022] Furthermore, in step S3-2-1 above, the extraction time is 1~10 min, and the O / A ratio is 1 / 1~1 / 5.

[0023] Furthermore, in step S3-2-1 above, the concentration of the extractant is 5-40 vol.% based on the total volume of the organic phase, the concentration of TBP is 5-20 vol.% and the remainder is diluent; the extractant is any one of N235, N236, N1923, and N507; the diluent is any one of sulfonated kerosene, n-heptane, toluene, xylene, and isoamyl alcohol.

[0024] Furthermore, in step S3-2-1 above, the concentration of the sulfuric acid solution is 0.5~3.0 mol / L.

[0025] Furthermore, in step S3-2-2 above, the extraction time is 1~10 min, and the O / A ratio is 1 / 1~1 / 5.

[0026] Furthermore, in step S3-2-2 above, the concentration of the extractant is 5-20 vol.% based on the total volume of the organic phase, the concentration of TBP is 5-20 vol.% and the remainder is diluent; the extractant is any one of P204 and P507; the diluent is any one of sulfonated kerosene, n-heptane, toluene, xylene and isoamyl alcohol.

[0027] Furthermore, in step S3-2-2 above, the concentration of sulfuric acid solution is 0.5~3.0 mol / L; the concentration of sodium hydroxide solution is 0.5~3.0 mol / L.

[0028] In S3-2 above, the calcium- and silicon-containing leaching residue is used to prepare low-carbon cement. Specifically, the leaching residue and cement clinker are mixed at a mass ratio of 1:4 to 10 and then ground into fine powder to obtain low-carbon cement.

[0029] The beneficial effects of this invention are as follows: This invention proposes a method for the synergistic recycling and high-value utilization of all metallurgical solid waste. Its core lies in mixing and formulating solid wastes such as iron-manganese slag, vanadium-extraction converter sludge, and blast furnace gas sludge, optimizing the composition, improving metal recovery efficiency, reducing iron to molten iron by controlling the reducing atmosphere and temperature, and allowing volatile metals such as zinc, indium, and gallium to enter the flue dust. The condensation characteristics of different metals are used to achieve graded dust collection, improving separation efficiency, while scandium is enriched in the slag phase. By optimizing the slag system composition, the scandium enrichment rate is improved, facilitating subsequent wet extraction.

[0030] This invention, through the coupling of reduction smelting and cascade condensation technologies, achieves the synergistic treatment and full-component recovery of various metallurgical solid wastes, demonstrating significant advantages: Environmentally, it achieves the harmlessness and substantial reduction of solid waste, mitigating environmental risks at the source; in terms of resources, through a multi-metal simultaneous recovery pathway, it produces molten iron and crude zinc while enriching strategic metals such as gallium and indium, greatly improving the efficiency of comprehensive resource utilization; economically and technically, this invention utilizes the inherent characteristics of solid waste to reduce energy consumption and costs, and creates considerable economic benefits through diversified product output, ultimately forming an environmentally friendly, resource-efficient, and economically feasible high-value utilization technology path for solid waste. This invention provides an innovative solution for the efficient recovery and high-value utilization of metallurgical solid waste, possessing significant industrial application value. Detailed Implementation

[0031] To make the technical problems, solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with the embodiments. Unless otherwise defined, all technical terms used herein have the same meaning as understood by one of ordinary skill in the art.

[0032] This invention mixes vanadium-extraction converter sludge with high iron content, iron-manganese slag, and blast furnace gas sludge to ensure total iron load. Simultaneously, it utilizes the inherent CaO, MgO, SiO2, and Al2O3 components in each solid waste to self-construct a predetermined slag system conducive to iron reduction and scandium enrichment during smelting, reducing the need for external flux additions. Blast furnace gas sludge contains 15-18.5% fixed carbon; using it as part of the raw material is equivalent to introducing an internal reducing agent, significantly reducing the consumption of external coke or pulverized coal, achieving waste-to-waste treatment and energy conservation.

[0033] The mixing ratio of blast furnace gas sludge, iron-manganese slag, and vanadium-extraction converter sludge is crucial for ensuring iron-carbon balance and slag alkalinity. If the proportion of iron-manganese slag or sludge is too high, it may lead to excessive slag volume, overly sticky slag, or alkalinity imbalance, hindering iron aggregation and separation, and diluting scandium concentration. If the ratio is too low, the synergistic effect between solid wastes cannot be fully utilized, resulting in insufficient internal carbon and requiring additional reducing agent. Therefore, the preferred mass ratio of blast furnace gas sludge, iron-manganese slag, and vanadium-extraction converter sludge is 1:0.2~1:0.4~1. This mass ratio ensures sufficient iron reduction, while the total amount of internal carbon and external reducing agent meets the reduction requirements of all metal oxides, and the resulting slag has suitable fluidity and scandium enrichment capacity.

[0034] In this invention, carbothermic reduction is performed under an inert atmosphere (nitrogen / argon), avoiding secondary oxidation of the metal. By controlling the temperature at 800~1500℃, iron oxides are reduced to liquid iron, while metals or their compounds with lower boiling points, such as Zn, Ga, and In, are reduced and directly volatilized into the flue gas, thus achieving complete separation from the molten iron.

[0035] This invention utilizes a stepped condensation process to efficiently separate and enrich flue gas rich in various volatile metals. Based on the differences in condensation temperatures of different metal vapors, physical classification is achieved by setting condensation zones with progressively decreasing temperatures. Ga, In, and their alloys have relatively high condensation temperatures; therefore, condensation into a liquid Ga-In alloy at 80-100°C is preferred, achieving initial separation from zinc. If the first-stage temperature is lower than the dew point of Ga and In, they will enter the second stage and mix with zinc, causing separation failure and difficulties in subsequent extraction. The second-stage temperature is crucial for ensuring zinc condenses into a liquid; excessively high temperatures result in incomplete zinc condensation, while excessively low temperatures may clog the pipeline. Therefore, Zn is preferably condensed into liquid crude zinc at 50-80°C, resulting in high purity, which can be directly sold as a product or further refined. The remaining trace amounts of metal vapor and entrained dust are recovered as residual ash at 5-25°C, which may contain other trace valuable elements; this process prevents their emission into the atmosphere.

[0036] In this invention, by controlling the slag system and using wet scandium extraction, the rare strategic metal scandium enriched in the slag is selectively dissolved into the solution for subsequent high-purity recovery through solvent extraction and other methods. An acidic solution with a concentration of 0.5~5 mol / L is used, and under moderate heating (60~80℃), Sc preferentially enters the solution, while large amounts of elements such as Ca and Si form precipitates such as calcium sulfate or are inhibited from dissolving, remaining in the leaching slag, thus achieving selective scandium leaching.

[0037] In this invention, calcium- and silicon-containing leaching residue is mixed with cement clinker at a mass ratio of 1:4 to 10 and then ground into fine powder to obtain low-carbon cement. This achieves a completely closed-loop process with zero waste discharge, and maximizes the utilization of the final solid residue. After acid leaching, the main components of the leaching residue are SiO2, CaSO4, and unreacted calcium silicate, which are precisely the siliceous and calcareous raw materials required for cement production, as well as setting regulators (gypsum). Therefore, it can be used as a high-quality cement admixture or to replace part of the clinker in the production of low-carbon cement without complex processing. This not only completely eliminates secondary solid waste but also has significant carbon emission reduction benefits due to the reduction in cement clinker usage.

[0038] The following specific embodiments will be provided to explain the solution of the present invention. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0039] Example 1: The main chemical components of the blast furnace gas sludge in this invention, by mass percentage, include 15.3% C, 34.20% Fe, 10.86% Zn, and 0.12% In; the main chemical components of the iron-manganese slag, by mass percentage, include 38.65% Fe, 3.23% Mn, 3.12% Mg, 1.68% Ca, and 0.5% Sc; the main chemical components of the vanadium-extraction converter sludge, by mass percentage, include 66.73% Fe, 2.85% Zn, and 0.2% Ga.

[0040] The synergistic recycling and high-value utilization of all components of metallurgical solid waste includes the following steps.

[0041] Blast furnace gas sludge, iron-manganese slag, and vanadium-extraction converter sludge are mixed in a mass ratio of 1:0.4:0.6 and crushed to below 100 mesh to ensure uniform mixing, resulting in a mixture. 10% coke, 0.5% bentonite, and 5.5% water are added to the mixture for granulation, resulting in pellets with a final particle size of 10mm. The pellets are then dried to obtain pelletized material.

[0042] The pellets are added to an electric furnace and reduced and smelted at 1400℃ for 60 minutes. Nitrogen or argon gas is continuously introduced during the roasting process to prevent oxidation. The reducing agent and the carbon contained in the blast furnace gas sludge can reduce the metal oxides in the three materials. The final reaction products are molten iron alloy, volatile metal vapor, and slag. Further processing steps and products are as follows: (1) The molten iron alloy was directly recycled. The iron recovery rate of the molten iron alloy was 96.38% and the purity was 98.65%.

[0043] (2) The volatile metal vapors are evaporated to a cascade circulating water condensation device. The first stage condensation temperature is 100℃, recovering the gallium-indium alloy; the second stage condensation temperature is 70℃, recovering the liquid crude zinc; and the third stage condensation temperature is 25℃, recovering the residual ash. Testing showed that the gallium recovery rate in the gallium-indium alloy was 90.35%, the indium recovery rate was 86.54%, and the mixed purity was 2.15%; the liquid crude zinc recovery rate was 89.25%, and the purity was 93.12%.

[0044] (3) Vanadium, manganese, scandium and other elements are enriched in the slag. The slag is leached with 4 mol / L sulfuric acid solution at a solid-liquid ratio of 1:4 (g / mL) for 90 min at a temperature of 75℃ to obtain a leachate containing vanadium, manganese and scandium. Calcium and silicon elements remain in the leaching residue, which can be used to prepare low-carbon cement.

[0045] (4) The leaching solution containing iron, vanadium, manganese and scandium was extracted for 5 min at room temperature with an O / A ratio of 1 / 2 using 10 vol.% N235 + 5 vol.% TBP + 85 vol.% sulfonated kerosene. The resulting organic phase loaded with vanadium and solutions of scandium and manganese were obtained. The organic phase was back-extracted with 1 mol / L sulfuric acid solution, and the vanadium recovery rate was 98.32%. The solutions of scandium and manganese were extracted for 2 min at room temperature with an O / A ratio of 1 / 2 using 5 vol.% P2O4 + 5 vol.% TBP + 90 vol.% sulfonated kerosene. The resulting organic phase loaded with scandium and manganese was obtained. The organic phase was first back-extracted with 0.5 mol / L sulfuric acid solution for manganese, and then back-extracted with 2 mol / L sodium hydroxide solution for scandium. The recovery rate of manganese was 95.43% and the recovery rate of scandium was 99.68%.

[0046] Example 2: The main chemical components of the blast furnace gas sludge in this invention, by mass percentage, include 18.3% C, 38.75% Fe, 13.45% Zn, and 0.17% In; the main chemical components of the iron-manganese slag, by mass percentage, include 35.85% Fe, 3.41% Mn, 3.53% Mg, 2.35% Ca, and 0.7% Sc; the main chemical components of the vanadium-extraction converter sludge, by mass percentage, include 65.58% Fe, 3.15% Zn, and 0.51% Ga.

[0047] The synergistic recycling and high-value utilization of all components of metallurgical solid waste includes the following steps.

[0048] Blast furnace gas sludge, iron-manganese slag, and vanadium-extraction converter sludge were mixed at a mass ratio of 1:0.75:0.75 and crushed to below 100 mesh to ensure uniform mixing, resulting in a mixture. 12% coke, 0.6% lime, and 5.8% water were added to the mixture for granulation, resulting in pellets with a final particle size of 12mm. The pellets were then dried to obtain pelletized material.

[0049] The pellets are added to an electric furnace and reduced and smelted at 1400℃ for 120 minutes. Nitrogen or argon is continuously introduced during the roasting process to prevent oxidation. The reducing agent and the carbon contained in the blast furnace gas sludge can reduce the metal oxides in the three materials. The final reaction products are molten iron alloy, volatile metal vapor, and slag. Further processing steps and products are as follows: (1) The molten iron alloy was directly recycled. The iron recovery rate in the molten iron alloy was 98.38%, and the purity was 99.26%.

[0050] (2) The volatile metal vapors are evaporated to a cascade circulating water condensation device. The first stage condensation temperature is 92℃, recovering the gallium-indium alloy; the second stage condensation temperature is 65℃, recovering the liquid crude zinc; and the third stage condensation temperature is 25℃, recovering the residual ash. Testing showed that the gallium recovery rate in the gallium-indium alloy was 89.68%, the indium recovery rate was 83.26%, and the mixed purity was 1.96%; the liquid crude zinc recovery rate was 84.63%, and the purity was 90.28%.

[0051] (3) Vanadium, manganese and scandium are enriched in the slag. The slag is leached with 6 mol / L sulfuric acid solution at a solid-liquid ratio of 1:5 (g / mL) for 120 min at a temperature of 80℃ to obtain a leachate containing iron, vanadium, manganese and scandium. Calcium and silicon remain in the leaching residue, which can be used to prepare low-carbon cement.

[0052] (4) The leaching solution containing iron, vanadium, manganese and scandium was extracted for 10 min at room temperature with an O / A ratio of 1 / 3 using 5 vol.% N1923 + 15 vol.% TBP + 80 vol.% sulfonated kerosene. The resulting organic phase loaded with vanadium and solutions of scandium and manganese were obtained. The organic phase was back-extracted with 1.5 mol / L sulfuric acid solution, and the vanadium recovery rate was 97.23%. The solutions of scandium and manganese were extracted for 5 min at room temperature with an O / A ratio of 1 / 2 using 10 vol.% P507 + 5 vol.% TBP + 85 vol.% sulfonated kerosene. The resulting organic phase loaded with scandium and manganese was obtained. The organic phase was first back-extracted with 1.0 mol / L sulfuric acid solution for manganese, and then back-extracted with 1.5 mol / L sodium hydroxide solution for scandium. The recovery rate of manganese was 93.10% and the recovery rate of scandium was 98.35%.

[0053] Example 3: The main chemical components of the blast furnace gas sludge in this invention, by mass percentage, include 15.8% C, 36.58% Fe, 16.27% Zn, and 0.18% In; the main chemical components of the iron-manganese slag, by mass percentage, include 38.76% Fe, 3.38% Mn, 3.07% Mg, 2.48% Ca, and 0.63% Sc; the main chemical components of the vanadium-extraction converter sludge, by mass percentage, include 61.26% Fe, 3.71% Zn, and 0.68% Ga.

[0054] The synergistic recycling and high-value utilization of all components of metallurgical solid waste includes the following steps.

[0055] Blast furnace gas sludge, iron-manganese slag, and vanadium-extraction converter sludge are mixed in a mass ratio of 1:1:0.5 and crushed to below 100 mesh to ensure uniform mixing, resulting in a mixture. 14% coke, 0.7% bentonite, and 6.0% water are added to the mixture for granulation, resulting in pellets with a final particle size of 11mm. The pellets are then dried to obtain pelletized material.

[0056] The pellets are added to an electric furnace and reduced and smelted at 1500℃ for 90 minutes. Nitrogen or argon gas is continuously introduced during the roasting process to prevent oxidation. The reducing agent and the carbon contained in the blast furnace gas sludge can reduce the metal oxides in the three materials. The final reaction products are molten iron alloy, volatile metal vapor, and slag. Further processing steps and products are as follows: (1) The molten iron alloy was directly recycled. The iron recovery rate in the molten iron alloy was 99.21%, and the purity was 99.18%.

[0057] (2) The volatile metal vapors are evaporated to a cascade circulating water condensation device. The first stage condensation temperature is 98℃, recovering the gallium-indium alloy; the second stage condensation temperature is 70℃, recovering the liquid crude zinc; and the third stage condensation temperature is 20℃, recovering the residual ash. Testing showed that the gallium recovery rate in the gallium-indium alloy was 96.68%, the indium recovery rate was 87.26%, and the mixed purity was 2.83%; the liquid crude zinc recovery rate was 89.06%, and the purity was 92.28%.

[0058] (3) Vanadium, manganese and scandium are enriched in the slag. The slag is leached with 5 mol / L sulfuric acid solution at a solid-liquid ratio of 1:4 (g / mL) for 150 min at a temperature of 60℃ to obtain a leachate containing iron, vanadium, manganese and scandium. Calcium and silicon remain in the leaching residue, which can be used to prepare low-carbon cement.

[0059] (4) The leaching solution containing iron, vanadium, manganese and scandium was extracted for 5 min at room temperature with an O / A ratio of 1 / 2 using 15 vol.% N236 + 10 vol.% TBP + 75 vol.% sulfonated kerosene. The resulting organic phase loaded with vanadium and solutions of scandium and manganese were obtained. The organic phase was back-extracted with 0.8 mol / L sulfuric acid solution, and the vanadium recovery rate was 96.38%. The solutions of scandium and manganese were extracted for 5 min at room temperature with an O / A ratio of 1 / 3 using 15 vol.% P507 + 10 vol.% TBP + 75 vol.% sulfonated kerosene. The resulting organic phase loaded with scandium and manganese was obtained. The organic phase was first back-extracted with 1.5 mol / L sulfuric acid solution for manganese, and then back-extracted with 2.0 mol / L sodium hydroxide solution for scandium. The recovery rate of manganese was 94.57% and the recovery rate of scandium was 99.49%.

[0060] Example 4: The main chemical components of the blast furnace gas sludge in this invention, by mass percentage, include 16.55% C, 38.14% Fe, 13.26% Zn, and 0.13% In; the main chemical components of the iron-manganese slag, by mass percentage, include 38.05% Fe, 3.63% Mn, 3.46% Mg, 2.51% Ca, and 0.59% Sc; the main chemical components of the vanadium-extraction converter sludge, by mass percentage, include 65.46% Fe, 3.19% Zn, and 0.54% Ga.

[0061] The synergistic recycling and high-value utilization of all components of metallurgical solid waste includes the following steps.

[0062] Blast furnace gas sludge, iron-manganese slag, and vanadium-extraction converter sludge are mixed at a mass ratio of 1:0.5:1 and crushed to below 100 mesh to ensure uniform mixing, resulting in a mixture. 14% coke, 0.6% water glass, and 6.5% water are added to the mixture for granulation, resulting in pellets with a final particle size of 12mm. The pellets are then dried to obtain pelletized material.

[0063] The pellets are added to an electric furnace and reduced and smelted at 1350℃ for 120 minutes. Nitrogen or argon is continuously introduced during the roasting process to prevent oxidation. The reducing agent and the carbon contained in the blast furnace gas sludge can reduce the metal oxides in the three materials. The final reaction products are molten iron alloy, volatile metal vapor, and slag. Further processing steps and products are as follows: (1) The molten iron alloy was directly recycled. The iron recovery rate in the molten iron alloy was 94.58%, and the purity was 96.27%.

[0064] (2) The volatile metal vapors are evaporated to a stepped circulating water condensation device. The first stage condensation temperature is 85℃, recovering the gallium-indium alloy; the second stage condensation temperature is 65℃, recovering the liquid crude zinc; and the third stage condensation temperature is 25℃, recovering the residual ash. Testing showed that the gallium recovery rate in the gallium-indium alloy was 91.15%, the indium recovery rate was 84.58%, and the mixed purity was 2.01%; the liquid crude zinc recovery rate was 91.36%, and the purity was 94.61%.

[0065] (3) Vanadium, manganese and scandium are enriched in the slag. The slag is leached with 6 mol / L sulfuric acid solution at a solid-liquid ratio of 1:6 (g / mL) for 120 min at a temperature of 80℃ to obtain a leachate containing iron, vanadium, manganese and scandium. Calcium and silicon remain in the leaching residue, which can be used to prepare low-carbon cement.

[0066] (4) The leaching solution containing iron, vanadium, manganese and scandium was extracted for 3 min at room temperature with an O / A ratio of 1 / 1 using 10 vol.% N235 + 5 vol.% TBP + 85 vol.% sulfonated kerosene. The resulting organic phase loaded with vanadium and solutions of scandium and manganese were obtained. The organic phase was back-extracted with 1.5 mol / L sulfuric acid solution, and the vanadium recovery rate was 97.65%. The solutions of scandium and manganese were extracted for 5 min at room temperature with an O / A ratio of 1 / 2 using 10 vol.% P2O4 + 10 vol.% TBP + 80 vol.% sulfonated kerosene. The resulting organic phase loaded with scandium and manganese was obtained. The organic phase was first back-extracted with 1.0 mol / L sulfuric acid solution for manganese, and then back-extracted with 1.5 mol / L sodium hydroxide solution for scandium. The recovery rate of manganese was 93.66% and the recovery rate of scandium was 97.57%.

Claims

1. A method for the synergistic recovery and high-value utilization of all components of metallurgical solid waste, comprising the following steps: S1. Blast furnace gas sludge, iron-manganese slag and vanadium-extraction converter sludge are crushed, mixed and then pulverized to obtain a mixture; S2. Mix the mixture, flux, reducing agent, binder and water evenly, form into pellets and dry to obtain pellet material; S3. Pelletized materials are reduced and smelted in an inert atmosphere at 800~1500℃ to obtain molten iron alloy, volatile metal vapor and slag; S3-1. The volatiles are collected separately as gallium-indium alloy, liquid crude zinc, and residual ash through multi-stage condensation; S3-2. The slag is wet leached to obtain a leachate containing vanadium, manganese and scandium and a leaching residue containing calcium and silicon. The leachate is solvent extracted to separate and recover vanadium, manganese and scandium.

2. The method for the synergistic recovery and high-value utilization of all components of metallurgical solid waste according to claim 1, characterized in that: In step S1, the mass ratio of the blast furnace gas sludge, iron-manganese slag and vanadium-extraction converter sludge is 1:0.2~1:0.4~1; the mixed material is crushed to below 100 mesh.

3. The method for the synergistic recovery and high-value utilization of all components of metallurgical solid waste according to claim 1, characterized in that: In step S2, the flux is alumina or silicon dioxide, and the amount of flux added is 3-7% of the mass of the mixture. In step S2, the reducing agent is coke or pulverized coal, and the amount of reducing agent added is 10-30% of the mass of the mixture. In step S2, the binder is at least one of bentonite, lime, and water glass, and the amount of binder added is 0.5-1.5% of the mass of the mixture. In step S2, the amount of water added is 5-15% of the mass of the mixture.

4. The method for the synergistic recovery and high-value utilization of all components of metallurgical solid waste according to claim 1, characterized in that: In step S2, the particle size of the ore pellets is 8~16mm.

5. The method for the synergistic recovery and high-value utilization of all components of metallurgical solid waste according to claim 1, characterized in that: In step S3, the reduction smelting time is 1 to 4 hours.

6. The method for synergistic recovery and high-value utilization of all components of metallurgical solid waste according to claim 1, characterized in that: In step S3-1, the multi-stage condensation specifically involves: the first stage condensate temperature being 80~100℃, recovering gallium-indium alloy; the second stage condensate temperature being 50~80℃, recovering liquid crude zinc; and the third stage condensate temperature being 5~25℃, recovering residual ash.

7. The method for the synergistic recovery and high-value utilization of all components of metallurgical solid waste according to claim 1, characterized in that: In step S3-2, the slag is wet-leached using an acidic solution; the acidic solution is a sulfuric acid solution, hydrochloric acid solution, phosphoric acid solution, or nitric acid solution with a concentration of 0.5~5 mol / L; the solid-liquid ratio of the slag to the acidic solution is 1g:3~10mL, the leaching time is 60~150min, and the leaching temperature is 25~90℃.

8. The method for synergistic recovery and high-value utilization of all components of metallurgical solid waste according to claim 1, characterized in that: In step S3-2, the solvent extraction specifically includes the following steps: S3-2-1. Using a vanadium-, scandium-, and manganese-containing leachate as the aqueous phase, an organic phase containing an extractant, a modifier TBP, and a diluent is used for extraction to obtain a vanadium-loaded organic phase and a scandium- and manganese solution. The organic phase is back-extracted with sulfuric acid solution to obtain vanadium. S3-2-2. Using a scandium and manganese solution as the aqueous phase, an organic phase containing an extractant, a modifier TBP, and a diluent is used for extraction to obtain an organic phase loaded with scandium and manganese. The organic phase is first back-extracted with sulfuric acid solution to obtain manganese, and then back-extracted with sodium hydroxide solution to obtain scandium. The extractant is either P204 or P507.

9. The method for the synergistic recovery and high-value utilization of all components of metallurgical solid waste according to claim 8, characterized in that: In step S3-2-1, the extraction time is 1-10 min, and the O / A ratio is 1 / 1-1 / 5; the concentration of the extractant is 5-40 vol.% based on the total volume of the organic phase, the concentration of TBP is 5-20 vol.%, and the remainder is diluent; the extractant is any one of N235, N236, N1923, and N507; the diluent is any one of sulfonated kerosene, n-heptane, toluene, xylene, and isoamyl alcohol; the sulfuric acid solution concentration is 0.5-3.0 mol / L. In step S3-2-2, the extraction time is 1-10 min, and the O / A ratio is 1 / 1-1 / 5; the concentration of the extractant is 5-20 vol.% based on the total volume of the organic phase, the concentration of TBP is 5-20 vol.%, and the remainder is diluent; the extractant is any one of P204 and P507; the diluent is any one of sulfonated kerosene, n-heptane, toluene, xylene, and isoamyl alcohol; the concentration of sulfuric acid solution is 0.5-3.0 mol / L; and the concentration of sodium hydroxide solution is 0.5-3.0 mol / L.

10. The method for synergistic recovery and high-value utilization of all components of metallurgical solid waste according to claim 1, characterized in that: In step S3-2, calcium- and silicon-containing leaching residue is used to prepare low-carbon cement. Specifically, the leaching residue and cement clinker are mixed at a mass ratio of 1:4 to 10 and then ground into fine powder to obtain low-carbon cement.