Method for comprehensive utilization of vanadium slag

Abstract

The present application relates to the technical field of vanadium hydrometallurgy, and discloses a method for resource utilization of all components of vanadium slag, which comprises the following steps: S1, vanadium slag calcine is added with water, a composite leaching agent and a composite intensifier to obtain a first ore slurry; S2, the pH of the first ore slurry is adjusted to be acidic, and a leaching reaction is performed to obtain a second ore slurry; S3, the second ore slurry is subjected to filtration separation to obtain a vanadium-containing leaching solution and a leaching residue I; S4, the leaching residue I is subjected to separation to obtain an iron concentrate and a remaining residue II; S5, water is added to the remaining residue to obtain a third ore slurry; and S6, hierarchical precipitation, the pH of the third ore slurry is adjusted, and manganese, magnesium and aluminum are recovered by precipitation, and finally, tailings are subjected to resource treatment. The present application adopts the mode of selective leaching and chelation for impurity removal, can realize chelation and precipitation of impurities while efficiently leaching vanadium, so as to obtain a vanadium-containing leaching solution with high purity, and meanwhile, various valuable metals are recovered.

Description

Technical Field

[0001] This invention relates to the field of vanadium hydrometallurgical technology, and more specifically, to a method for the resource utilization of all components of vanadium slag. Background Technology

[0002] Vanadium possesses numerous excellent physicochemical and mechanical properties, leading to its widespread application in modern industry. With the rapid development of my country's modernization, the demand for vanadium and its compounds is increasing, and the requirements for high-purity vanadium and its compounds are becoming increasingly stringent. Currently, vanadium extraction from vanadium slag primarily utilizes roasting processes, mainly including sodium roasting and calcification roasting. Sodium roasting accounts for over 90% of vanadium extraction capacity from vanadium slag and is the mainstream vanadium extraction process adopted by major vanadium compound producers both domestically and internationally. Specifically, the sodium roasting process uses sodium salts such as soda ash and sodium chloride as additives. Through high-temperature oxidation-sodium roasting, the multivalent vanadium in the vanadium-containing raw material is converted into water-soluble pentavalent vanadium sodium salt. The roasting product is then leached with water to obtain a leachate containing vanadium and a small amount of impurities. After impurity removal, the vanadium-containing leachate is adjusted to a specific pH value, and then ammonium salts are added to precipitate vanadium as ammonium polyvanadate. The ammonium salts are then thermally decomposed to obtain vanadium pentoxide. However, in this process, vanadium in the vanadium slag mainly exists in the form of vanadium-iron spinel, which is chemically stable and difficult to decompose, resulting in low leaching efficiency. In addition, the vanadium slag contains a large amount of silicon-containing low-melting-point substances, and increasing the reaction temperature will lead to ring formation, making it difficult to increase the vanadium extraction rate by increasing the temperature. At the same time, the sodium roasting process will decompose and produce harmful kiln gas.

[0003] To address issues such as charge agglomeration and ring formation during the sodium roasting process, domestic research and development efforts are currently focused on breakthroughs in sodium roasting technology. Among these efforts, Panzhihua Iron and Steel Group (Pangang) has constructed the Xichang Vanadium Products Plant using a vanadium slag calcification roasting-acid leaching vanadium extraction process. Calcification roasting avoids the sintering phenomenon associated with traditional sodium roasting; however, because the calcification roasting process still requires a high-temperature roasting process, it also faces mass transfer obstacles during roasting, resulting in a vanadium recovery rate of less than 80%.

[0004] Vanadium slag typically contains impurities such as MnO, Fe2O3, and MgO. During the leaching process, due to poor leaching selectivity, these impurities, including Fe, Mn, and Mg, enter the solution along with vanadium (V). The leaching of these impurities not only affects the subsequent vanadium precipitation but also results in a high impurity content in the final product, leading to poor market competitiveness. Therefore, to obtain high-quality vanadium pentoxide, the vanadium leachate must be purified after leaching and before vanadium precipitation. To address the poor acid leaching selectivity, existing technologies often use chelating agents to simultaneously remove impurities during the leaching process. However, commonly used mercaptotriazine chelating agents lack stability in strong acid leaching systems, easily decomposing and failing. Furthermore, conventional polyacrylamide flocculants are difficult to biodegrade, easily causing secondary water pollution. Simultaneously, existing processes only achieve vanadium extraction and the separation of a small amount of impurities, failing to achieve the complete recovery of valuable metals from the vanadium slag and the harmless resource utilization of the tailings, resulting in low resource utilization and significant solid waste disposal pressure. Summary of the Invention

[0005] This invention addresses the technical problems of poor acid leaching selectivity, complex impurity removal processes, and low reagent stability in existing vanadium slag extraction processes. Furthermore, current vanadium slag extraction processes generally employ a route of first full leaching followed by stepwise impurity removal, requiring additional complex impurity removal steps such as extraction and ion exchange. This results in long processes, high costs, and the commonly used chelating agents and flocculants suffer from poor stability and insufficient environmental friendliness. Therefore, this invention employs a selective leaching followed by chelation impurity removal method. This allows for efficient vanadium leaching while simultaneously chelating and precipitating impurities, yielding a high-purity vanadium-containing leachate and recovering multiple valuable metals.

[0006] Specifically, This invention provides a method for the resource utilization of all components of vanadium slag, comprising the following steps: S1 Preparation of slurry: Water, composite leaching agent and composite strengthening agent are added to vanadium slag roasted clinker and mixed to obtain the first slurry; As mentioned above, vanadium slag includes at least one of the following: vanadium slag from vanadium-titanium magnetite smelting converters, vanadium tailings from coal stone extraction, vanadium slag from shale extraction, and vanadium-containing solid waste from chemical processing. For example, vanadium slag is first prepared by slag-forming blast furnace iron through converter blowing, and then the vanadium slag is roasted in an air atmosphere.

[0007] As mentioned above, vanadium slag roasted clinker includes at least one clinker or a mixture thereof obtained by vanadium slag through sodium roasting, calcification roasting, oxidative roasting, or roasting with composite additives. For example, vanadium slag roasted clinker is obtained by oxidative roasting of vanadium slag from a vanadium-titanium magnetite converter at 650-850℃ for 2-4 hours. The roasted clinker contains, by mass percentage, 8-15 wt% V2O5, 4-8 wt% MnO, 3-6 wt% Fe2O3, 2-4 wt% MgO, and 1-3 wt% Al2O3, with the balance being TiO2, SiO2, CaO, Cr2O3, and trace impurities; the proportion of particles with a particle size less than 0.074 mm in the roasted clinker is ≥80 wt%.

[0008] As described above, the composite leaching agent includes organic acid, inorganic acid, and reducing agent; the organic acid includes at least one of citric acid, oxalic acid, and tartaric acid; the inorganic acid includes at least one of sulfuric acid, hydrochloric acid, and nitric acid; the reducing agent includes at least one of sodium hypophosphite, sodium sulfite, sodium phosphite, and ascorbic acid; the mass ratio of organic acid, inorganic acid, and reducing agent is (1-3):(5-10):(0.5-2); the amount of composite leaching agent added is 5%-12% of the mass of vanadium slag roasted clinker. If the composite leaching agent includes citric acid, sulfuric acid, and sodium hypophosphite, the preferred mass ratio of the components is 2:8:1; the preferred amount of composite leaching agent added is 8%-10% of the mass of vanadium slag roasted clinker.

[0009] The aforementioned composite reinforcing agent includes a chelating agent, a modified flocculant, and a dispersant; the chelating agent includes at least one of sodium ethylenediamine dithiocarbamate, diethylenetriamine pentamethylphosphonic acid, and aminotrimethylenephosphonic acid; the modified flocculant includes at least one of starch-grafted acrylamide copolymer, carboxymethyl cellulose-grafted polyacrylamide, and chitosan-grafted acrylamide; the dispersant includes at least one of sodium dodecylbenzenesulfonate, sodium lignosulfonate, and sodium polycarboxylate; the mass ratio of the chelating agent, modified flocculant, and dispersant is (3-8):(1-3):(0.2-1); the amount of composite reinforcing agent added is 0.5%-3% of the mass of vanadium slag roasted clinker. The aforementioned starch-grafted acrylamide copolymer is selected as a water-soluble, anionic copolymer with a weight-average molecular weight of 5 million-12 million and a grafting rate of 40%-75%. Specifically, the composite reinforcing agent can be selected from sodium ethylenediamine dithiocarbamate, starch-grafted acrylamide copolymer and sodium dodecylbenzenesulfonate. The preferred mass ratio of the components of the composite reinforcing agent is 5:2:0.5. The amount of composite reinforcing agent added is 1%-2% of the mass of vanadium slag roasted clinker.

[0010] In the aforementioned composite leaching agent, citric acid, sulfuric acid, and sodium hypophosphite are used as examples for specific explanation: citric acid forms a stable vanadium citrate complex with vanadium ions, which can significantly promote the dissolution of vanadium; sulfuric acid provides the hydrogen ion environment required for leaching; and sodium hypophosphite... 3+Reduced to Fe 2+ It not only inhibits excessive leaching of iron, but also forms a more stable chelate with sodium ethylenediamine dithiocarbamate, preventing the back dissolution of impurities.

[0011] In the aforementioned example, sodium ethylenediamine dithiocarbamate, starch-grafted acrylamide copolymer, and sodium dodecylbenzenesulfonate are used as composite reinforcing agents for specific illustration: Sodium ethylenediamine dithiocarbamate in the composite reinforcing agent is a bidentate chelating agent, containing multiple dithiocarboxyl active groups in its molecule, which can react with Fe... 2+ Mn 2+ Mg 2+ Al 3+ It forms stable four-membered ring chelates within a pH range of 2.0-4.5, with extremely low solubility and is not easily reversed; the starch-grafted acrylamide copolymer is a green flocculant that is biodegradable and rapidly flocculates and chelates precipitates through adsorption bridging, achieving efficient solid-liquid separation; sodium dodecylbenzenesulfonate can improve the dispersibility of slurry, increase the contact efficiency between reagents and mineral particles, and enhance the leaching and chelation reaction rates.

[0012] In the aforementioned context, the solid-liquid ratio of the first slurry is 1:(2-5)kg / L.

[0013] S2 Selective Leaching: The pH of the first slurry is adjusted to acidity, and selective leaching is carried out through a leaching reaction. During the leaching process, the composite leaching agent selectively dissolves vanadium and forms a stable soluble complex. The composite reinforcing agent undergoes a chelation reaction with the simultaneously dissolved impurity ions such as iron, manganese, magnesium, and aluminum to generate insoluble chelates, which rapidly form stable floc precipitates under the action of modified flocculants. This achieves simultaneous completion of leaching and impurity removal, and the second slurry is obtained after the reaction is completed. In the aforementioned process, alkali or acid is added to adjust the pH of the first slurry (2.0-3.5), the leaching temperature is controlled at 120-180℃, the leaching time is 30-120 min, and the stirring rate is 300-800 r / min. Preliminary conditional tests show that when the temperature is below 180℃ and the leaching time is less than 60 min, the vanadium leaching reaction is insufficient, and the chelation and removal of impurities deteriorates; when the temperature is above 180℃ and the leaching time exceeds 120 min, it exacerbates the dissolution of large amounts of impurities, increases energy consumption, and reduces economic efficiency. An operating range of 180℃ and 60-120 min can simultaneously achieve high vanadium leaching rates and deep purification of the leaching solution, balancing process parameters and production costs.

[0014] Specifically, the pH of the first slurry is adjusted to 2.0-3.5 using a 0.05 mol / L sulfuric acid solution, the leaching temperature is controlled at 180℃, the leaching time is 60-120 min, and the stirring rate is 500-600 r / min. The higher hydrothermal temperature can fully destroy the mineral phase structure of the vanadium slag clinker, increasing the vanadium leaching rate to over 99.8%. At the same time, it ensures that impurity ions and composite reinforcing agents can fully undergo chelation precipitation reaction to obtain a vanadium-containing leachate with lower impurity content.

[0015] S3 Solid-liquid separation: The second slurry is pressurized (operating pressure 0.3-0.8 MPa) and filtered to obtain vanadium-containing leachate and leaching residue. The leaching residue is washed with a composite strengthening agent aqueous solution, and the washing liquid is incorporated into the vanadium-containing leachate. The mass concentration of the washing liquid is 0.1%-0.5%.

[0016] S4 Magnetic separation for iron extraction: The leaching residue after washing is separated by weak magnetic separation to obtain iron concentrate product with TFe grade ≥60% and non-magnetic separation residue. In the aforementioned weak magnetic separation, the magnetic field strength is 800-1500 Oe.

[0017] S5 Residue Pulping: Water is added to the non-magnetic separation residue to obtain the third slurry. The solid-liquid ratio of the third slurry is controlled at 1:(4-8) kg / L.

[0018] S6 graded sedimentation: The pH of the third slurry is adjusted in stages, and manganese, magnesium and aluminum compounds are recovered through gradient sedimentation. Finally, the tailings are modified and used to prepare cement admixtures or concrete fillers, realizing the resource utilization of all components.

[0019] As described above, fractional precipitation was carried out using a 2-5 mol / L sodium hydroxide solution, as detailed below: First stage: Adjust the pH value to weakly acidic (6.5-7.0) to precipitate and recover aluminum hydroxide; Second stage: Adjust the pH value to moderately alkaline (9.0-9.5) and precipitate and recover manganese hydroxide; Third stage: Adjust the pH value to strongly alkaline (11.0-11.5) to precipitate and recover magnesium hydroxide.

[0020] The beneficial effects achieved by this invention are as follows: The composite leaching agent provided by this invention adopts an organic acid-inorganic acid-reducing agent composite system. The organic acid can form a stable and soluble complex with vanadium, promoting the efficient dissolution of vanadium. The reducing agent can remove Fe from the system. 3+ Reduced to Fe 2+ This reduces iron leaching and provides a more suitable reaction environment for the chelating agent.

[0021] The composite reinforcing agent provided by this invention uses sodium ethylenediamine dithiocarbamate as the core chelating agent, which has a strong selective chelating ability for impurity ions such as iron, manganese, magnesium, and aluminum. It exhibits excellent stability in strong acid leaching systems. Simultaneously, it incorporates biodegradable starch-grafted acrylamide flocculant and dispersant to achieve simultaneous impurity removal during the leaching process. The vanadium leaching rate can reach up to 99.8%, and the resulting vanadium-containing leachate has a high vanadium concentration. The content of iron, manganese, magnesium, and aluminum impurities is effectively suppressed, and it can be directly used for subsequent vanadium precipitation to prepare high-purity vanadium pentoxide, thereby eliminating the need for subsequent impurity removal processes, significantly shortening the process flow, and reducing production costs.

[0022] This invention recovers iron concentrate from leaching residue through weak magnetic separation, and then recovers valuable metals such as manganese, magnesium, and aluminum through gradient precipitation. The comprehensive recovery rate of valuable metals can reach a high level. Finally, the tailings can be modified and used entirely for building material preparation without generating secondary solid waste, thus solving the environmental problem of tailings storage in traditional processes.

[0023] In summary, the process provided by this invention is green and environmentally friendly, and suitable for industrial production; the composite reinforcing agent used is biodegradable, with no secondary pollution; the leaching temperature and time are significantly reduced compared to traditional processes, resulting in a significant decrease in energy consumption; the process steps are continuous and controllable, requiring no additional complex equipment, and can be directly adapted to the upgrading and transformation of existing vanadium extraction production lines, with broad prospects for industrial application. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0025] Example The vanadium slag roasted clinker used in this example was obtained by oxidizing and roasting vanadium slag from a vanadium-titanium magnetite converter at 750℃ for 3 hours. The process employed a high-pressure reactor with a paddle mixer, enabling hydrothermal leaching at 120-180℃ and achieving uniform mass transfer in the conventional liquid-to-solid ratio slurry suspension. The main chemical components of the roasted clinker, by mass percentage, were: V₂O₅ 12.6 wt%, MnO 6.8 wt%, Fe₂O₃ 4.2 wt%, MgO 3.1 wt%, Al₂O₃ 2.2 wt%, SiO₂ 18.5 wt%, and CaO 24.3 wt%; the proportion of particles with a diameter less than 0.074 mm was 85 wt%.

[0026] Example 1 Take 1 kg of the above-mentioned vanadium slag roasted clinker, add 4 L of water, then add a composite leaching agent and a composite reinforcing agent, and stir evenly to obtain the first slurry. The composite leaching agent is composed of citric acid, sulfuric acid, and sodium hypophosphite in a mass ratio of 2:8:1, and the amount added is 8% of the mass of the roasted clinker. The composite reinforcing agent is composed of sodium ethylenediamine dithiocarbamate, starch-grafted acrylamide copolymer, and sodium dodecylbenzenesulfonate in a mass ratio of 5:2:0.5, and the amount added is 1% of the mass of the roasted clinker. Adjust the pH of the first slurry to 3.0 using a 0.05 mol / L sulfuric acid solution, control the leaching temperature at 180℃, the stirring rate at 550 r / min, and the leaching time at 60 min to obtain the second slurry. Vacuum filter the second slurry to obtain a vanadium-containing leachate and leaching residue I. Leaching residue I is washed with a 0.2% (w / w) composite reinforcing agent aqueous solution, and the washing liquid is added to the vanadium-containing leachate. Leaching residue I was subjected to wet weak magnetic separation at a magnetic field strength of 1200 Oe to obtain iron concentrate and residual residue II. 3 L of water was added to residual residue II and stirred to prepare a third slurry. The pH was adjusted in stages using a 3 mol / L sodium hydroxide solution: first, the pH was adjusted to 6.8 to precipitate and recover aluminum hydroxide; then, the pH was adjusted to 9.2 to precipitate and recover manganese hydroxide; finally, the pH was adjusted to 11.2 to precipitate and recover magnesium hydroxide. The final tailings were modified and used in the preparation of cement admixtures.

[0027] In this embodiment, the vanadium leaching rate was 99.72%, and the vanadium concentration in the resulting vanadium-containing leachate was 17.60 g / L, the iron ion concentration was 0.08 g / L, the manganese concentration was 0.04 g / L, the magnesium concentration was 0.03 g / L, and the aluminum concentration was 0.05 g / L; the TFe grade of the iron concentrate was 62.35%, the iron recovery rate was 88.42%, and the comprehensive recovery rate of manganese, magnesium, and aluminum was 91.26%.

[0028] Example 2 Take 1 kg of the above-mentioned vanadium slag roasted clinker, add 4 L of water, then add a composite leaching agent and a composite reinforcing agent, and stir evenly to obtain the first slurry. The composite leaching agent is composed of citric acid, sulfuric acid, and sodium hypophosphite in a mass ratio of 2:8:1, and is added at 10% of the mass of the roasted clinker. The composite reinforcing agent is composed of sodium ethylenediamine dithiocarbamate, starch-grafted acrylamide copolymer, and sodium dodecylbenzenesulfonate in a mass ratio of 6:2:0.5, and is added at 2% of the mass of the roasted clinker. Adjust the pH of the first slurry to 2.5 using a 0.05 mol / L sulfuric acid solution, control the leaching temperature at 180℃, the stirring rate at 600 r / min, and the leaching time at 90 min to obtain the second slurry. Vacuum filter the second slurry to obtain a vanadium-containing leachate and leaching residue I. Leaching residue I is washed with a 0.3% (w / w) composite reinforcing agent aqueous solution, and the washing liquid is added to the vanadium-containing leachate. Leaching residue I was subjected to wet weak magnetic separation at a magnetic field strength of 1200 Oe to obtain iron concentrate and residual residue II. 3 L of water was added to residual residue II and stirred to prepare a third slurry. The pH was adjusted in stages using a 3 mol / L sodium hydroxide solution: first, the pH was adjusted to 6.5 to precipitate and recover aluminum hydroxide; then, the pH was adjusted to 9.0 to precipitate and recover manganese hydroxide; finally, the pH was adjusted to 11.0 to precipitate and recover magnesium hydroxide. The final tailings were modified and used in the preparation of cement admixtures.

[0029] In this embodiment, the vanadium leaching rate was 99.85%, and the vanadium concentration in the resulting vanadium-containing leachate was 17.62 g / L, the iron ion concentration was 0.05 g / L, the manganese concentration was 0.03 g / L, the magnesium concentration was 0.02 g / L, and the aluminum concentration was 0.03 g / L; the TFe grade of the iron concentrate was 63.10%, the iron recovery rate was 89.05%, and the comprehensive recovery rate of manganese, magnesium, and aluminum was 92.45%.

[0030] Example 3 Take 1 kg of the above-mentioned vanadium slag roasted clinker, add 3 L of water, then add a composite leaching agent and a composite reinforcing agent, and stir evenly to obtain the first slurry. The composite leaching agent is composed of oxalic acid, hydrochloric acid, and sodium sulfite in a mass ratio of 1:5:0.5, and is added at 5% of the mass of the roasted clinker. The composite reinforcing agent is composed of diethylenetriaminepentamethylphosphonic acid, carboxymethyl cellulose-grafted polyacrylamide, and sodium lignosulfonate in a mass ratio of 3:1:0.2, and is added at 0.5% of the mass of the roasted clinker. Adjust the pH of the first slurry to 2.0 using a 0.05 mol / L sulfuric acid solution, control the leaching temperature at 120℃, the stirring rate at 300 r / min, and the leaching time at 45 min to obtain the second slurry. Vacuum filter the second slurry to obtain a vanadium-containing leachate and leaching residue I. Wet weak magnetic separation is performed on leaching residue I under a magnetic field strength of 800 Oe to obtain iron concentrate and residual residue II. Add 3 L of water to the remaining residue II and stir to prepare the third slurry. Use 3 mol / L sodium hydroxide solution to adjust the pH value in stages. First, adjust the pH to 7.0 to precipitate and recover aluminum hydroxide. Then adjust the pH to 9.5 to precipitate and recover manganese hydroxide. Finally, adjust the pH to 11.5 to precipitate and recover magnesium hydroxide. The final tailings are modified and used for the preparation of cement admixtures.

[0031] In this embodiment, the vanadium leaching rate was 95.62%, and the vanadium concentration in the resulting vanadium-containing leachate was 22.50 g / L, the iron ion concentration was 0.32 g / L, the manganese concentration was 0.28 g / L, the magnesium concentration was 0.21 g / L, and the aluminum concentration was 0.18 g / L; the TFe grade of the iron concentrate was 60.85%, the iron recovery rate was 85.32%, and the comprehensive recovery rate of manganese, magnesium, and aluminum was 85.76%.

[0032] Example 4 Take 1 kg of the above-mentioned vanadium slag roasted clinker, add 5 L of water, then add a composite leaching agent and a composite reinforcing agent, and stir evenly to obtain the first slurry. The composite leaching agent is composed of tartaric acid, nitric acid, and ascorbic acid in a mass ratio of 3:10:2, and the amount added is 12% of the mass of the roasted clinker. The composite reinforcing agent is composed of aminotrimethylenephosphonic acid, chitosan-grafted acrylamide, and sodium polycarboxylate in a mass ratio of 8:3:1, and the amount added is 3% of the mass of the roasted clinker. Adjust the pH of the first slurry to 3.5 using a 0.05 mol / L sulfuric acid solution, control the leaching temperature at 180℃, the stirring rate at 500 r / min, and the leaching time at 120 min to obtain the second slurry. Vacuum filter the second slurry to obtain a vanadium-containing leachate and leaching residue I. Leaching residue I is washed with a 0.5% (w / w) composite reinforcing agent aqueous solution, and the washing liquid is added to the vanadium-containing leachate. Leaching residue I was subjected to wet weak magnetic separation at a magnetic field strength of 1500 Oe to obtain iron concentrate and residual residue II. 3 L of water was added to residual residue II and stirred to prepare a third slurry. The pH was adjusted in stages using a 3 mol / L sodium hydroxide solution: first, the pH was adjusted to 6.8 to precipitate and recover aluminum hydroxide; then, the pH was adjusted to 9.2 to precipitate and recover manganese hydroxide; finally, the pH was adjusted to 11.2 to precipitate and recover magnesium hydroxide. The final tailings were modified and used in the preparation of cement admixtures.

[0033] In this embodiment, the vanadium leaching rate was 99.35%, and the vanadium concentration in the resulting vanadium-containing leachate was 14.03 g / L, the iron ion concentration was 0.15 g / L, the manganese concentration was 0.10 g / L, the magnesium concentration was 0.08 g / L, and the aluminum concentration was 0.12 g / L; the TFe grade of the iron concentrate was 61.52%, the iron recovery rate was 86.78%, and the comprehensive recovery rate of manganese, magnesium, and aluminum was 89.34%.

[0034] Example 5 Take 1 kg of the above-mentioned vanadium slag roasted clinker, add 4 L of water, then add a composite leaching agent and a composite reinforcing agent, and stir evenly to obtain the first slurry. The composite leaching agent is composed of citric acid, sulfuric acid, and sodium hypophosphite in a mass ratio of 2:8:1, and the amount added is 8% of the mass of the roasted clinker. The composite reinforcing agent is composed of sodium ethylenediamine dithiocarbamate, starch-grafted acrylamide copolymer, and sodium dodecylbenzenesulfonate in a mass ratio of 4:2:0.5, and the amount added is 1% of the mass of the roasted clinker. Adjust the pH of the first slurry to 2.0 using a 0.05 mol / L sulfuric acid solution, control the leaching temperature at 180℃, the stirring rate at 500 r / min, and the leaching time at 120 min to obtain the second slurry. Vacuum filter the second slurry to obtain a vanadium-containing leachate and leaching residue I. Wet weak magnetic separation is performed on leaching residue I under a magnetic field strength of 1000 Oe to obtain iron concentrate and residual residue II. Add 3 L of water to the remaining residue II and stir to prepare the third slurry. Use 3 mol / L sodium hydroxide solution to adjust the pH value in stages. First, adjust the pH to 6.8 to precipitate and recover aluminum hydroxide. Then adjust the pH to 9.2 to precipitate and recover manganese hydroxide. Finally, adjust the pH to 11.2 to precipitate and recover magnesium hydroxide. The final tailings are modified and used for the preparation of cement admixtures.

[0035] In this embodiment, the vanadium leaching rate was 99.91%, and the vanadium concentration in the resulting vanadium-containing leachate was 17.63 g / L, the iron ion concentration was 0.03 g / L, the manganese concentration was 0.02 g / L, the magnesium concentration was 0.01 g / L, and the aluminum concentration was 0.02 g / L; the TFe grade of the iron concentrate was 63.02%, the iron recovery rate was 89.18%, and the comprehensive recovery rate of manganese, magnesium, and aluminum was 93.05%.

[0036] Example 6 Vanadium extraction tailings from coal shale (V₂O₅ content approximately 9.8 wt%) were used as raw material. After oxidative roasting at 800℃ for 2 h, the material was ground until the proportion of particles smaller than 0.074 mm was 82 wt%. 1 kg of the ground clinker was taken, 4 L of water was added, and then a composite leaching agent and a composite reinforcing agent were added and stirred evenly to obtain the first slurry. The composite leaching agent was composed of citric acid, sulfuric acid, and sodium hypophosphite in a mass ratio of 2:8:1, and the amount added was 8% of the roasted clinker mass. The composite reinforcing agent was composed of sodium ethylenediamine dithiocarbamate, starch-grafted acrylamide copolymer, and sodium dodecylbenzenesulfonate in a mass ratio of 5:2:0.5, and the amount added was 1.5% of the roasted clinker mass. The pH of the first slurry was adjusted to 2.5 using a 0.05 mol / L sulfuric acid solution, and the leaching temperature was controlled at 180℃, the stirring rate at 550 r / min, and the leaching time at 90 min to obtain the second slurry. The second slurry was vacuum filtered to obtain a vanadium-containing leaching solution and leaching residue I. Leaching residue I was then subjected to wet weak magnetic separation at a magnetic field strength of 1200 Oe to obtain iron concentrate and residual residue II. 3 L of water was added to residual residue II and stirred to prepare a third slurry. The pH was adjusted in stages using a 3 mol / L sodium hydroxide solution: first, the pH was adjusted to 6.8 to precipitate and recover aluminum hydroxide; then, the pH was adjusted to 9.2 to precipitate and recover manganese hydroxide; finally, the pH was adjusted to 11.2 to precipitate and recover magnesium hydroxide. The final tailings were modified and used in the preparation of cement admixtures.

[0037] In this embodiment, the vanadium leaching rate was 97.85%, and the vanadium concentration in the resulting vanadium-containing leachate was 14.74 g / L, the iron ion concentration was 0.12 g / L, the manganese concentration was 0.08 g / L, the magnesium concentration was 0.06 g / L, and the aluminum concentration was 0.09 g / L; the TFe grade of the iron concentrate was 59.75%, the iron recovery rate was 82.36%, and the comprehensive recovery rate of manganese, magnesium, and aluminum was 87.52%.

[0038] Comparative Example 1 Take 1 kg of the above-mentioned vanadium slag roasted clinker, add 4 L of water, and then add a composite leaching agent (without adding a composite reinforcing agent), and stir evenly to obtain the first slurry; wherein the composite leaching agent is composed of citric acid, sulfuric acid, and sodium hypophosphite in a mass ratio of 2:8:1, and the amount added is 8% of the mass of the roasted clinker. Adjust the pH of the first slurry to 3.0 using 0.05 mol / L sulfuric acid solution, control the leaching temperature at 180℃, the stirring rate at 550 r / min, and the leaching time at 60 min to obtain the second slurry. Vacuum filter the second slurry to obtain vanadium-containing leachate and leaching residue I. Perform wet weak magnetic separation on leaching residue I under a magnetic field strength of 1200 Oe to obtain iron concentrate and residual residue II. Add 3 L of water to the remaining residue II and stir to prepare the third slurry. Use 3 mol / L sodium hydroxide solution to adjust the pH value in stages. First, adjust the pH to 6.8 to precipitate and recover aluminum hydroxide, then adjust the pH to 9.2 to precipitate and recover manganese hydroxide, and finally adjust the pH to 11.2 to precipitate and recover magnesium hydroxide.

[0039] In this comparative example, the vanadium leaching rate was 97.52%, and the vanadium concentration in the resulting vanadium-containing leachate was 17.21 g / L, the iron ion concentration was 2.85 g / L, the manganese concentration was 1.92 g / L, the magnesium concentration was 1.35 g / L, and the aluminum concentration was 1.05 g / L; the TFe grade of the iron concentrate was 61.05%, the iron recovery rate was 85.62%, and the comprehensive recovery rate of manganese, magnesium, and aluminum was 78.35%.

[0040] Comparative Example 2 Take 1 kg of the above-mentioned vanadium slag roasted clinker, add 4 L of water, then add a composite leaching agent and a single chelating agent (excluding modified flocculants and dispersants), and stir evenly to obtain the first slurry; wherein the composite leaching agent is composed of citric acid, sulfuric acid, and sodium hypophosphite in a mass ratio of 2:8:1, and the amount added is 8% of the mass of the roasted clinker; the single chelating agent is sodium ethylenediamine dithiocarbamate, and the amount added is 1% of the mass of the roasted clinker. The pH of the first slurry is adjusted to 3.0 using 0.05 mol / L sulfuric acid solution, the leaching temperature is controlled at 180℃, the stirring rate is 550 r / min, and the leaching time is 60 min to obtain the second slurry. The second slurry is vacuum filtered to obtain vanadium-containing leachate and leaching residue I. The leaching residue I is separated by wet weak magnetic separation under a magnetic field strength of 1200 Oe to obtain iron concentrate and residual residue II. Add 3 L of water to the remaining residue II and stir to prepare the third slurry. Use 3 mol / L sodium hydroxide solution to adjust the pH value in stages. First, adjust the pH to 6.8 to precipitate and recover aluminum hydroxide, then adjust the pH to 9.2 to precipitate and recover manganese hydroxide, and finally adjust the pH to 11.2 to precipitate and recover magnesium hydroxide.

[0041] In this comparative example, the vanadium leaching rate was 98.25%, and the vanadium concentration in the resulting vanadium-containing leachate was 17.34 g / L, the iron ion concentration was 1.25 g / L, the manganese concentration was 0.86 g / L, the magnesium concentration was 0.52 g / L, and the aluminum concentration was 0.48 g / L; the TFe grade of the iron concentrate was 61.32%, the iron recovery rate was 86.15%, and the comprehensive recovery rate of manganese, magnesium, and aluminum was 81.24%.

[0042] Comparative Example 3 Take 1 kg of the above-mentioned vanadium slag roasted clinker, add 4 L of water, then add a composite leaching agent and a single flocculant (excluding chelating agents and dispersants), and stir evenly to obtain the first slurry; wherein the composite leaching agent is composed of citric acid, sulfuric acid, and sodium hypophosphite in a mass ratio of 2:8:1, and the amount added is 8% of the mass of the roasted clinker; the single flocculant is a starch-grafted acrylamide copolymer, and the amount added is 1% of the mass of the roasted clinker. Adjust the pH of the first slurry to 3.0 with 0.05 mol / L sulfuric acid solution, control the leaching temperature at 180℃, the stirring rate at 550 r / min, and the leaching time at 60 min to obtain the second slurry. Vacuum filter the second slurry to obtain vanadium-containing leachate and leaching residue I. Wet weak magnetic separation is performed on leaching residue I under a magnetic field strength of 1200 Oe to obtain iron concentrate and residual residue II. Add 3 L of water to the remaining residue II and stir to prepare the third slurry. Use 3 mol / L sodium hydroxide solution to adjust the pH value in stages. First, adjust the pH to 6.8 to precipitate and recover aluminum hydroxide, then adjust the pH to 9.2 to precipitate and recover manganese hydroxide, and finally adjust the pH to 11.2 to precipitate and recover magnesium hydroxide.

[0043] In this comparative example, the vanadium leaching rate was 97.68%, and the vanadium concentration in the resulting vanadium-containing leachate was 17.24 g / L, the iron ion concentration was 2.35 g / L, the manganese concentration was 1.58 g / L, the magnesium concentration was 1.12 g / L, and the aluminum concentration was 0.86 g / L; the TFe grade of the iron concentrate was 61.10%, the iron recovery rate was 85.75%, and the comprehensive recovery rate of manganese, magnesium, and aluminum was 79.42%.

[0044] Comparative Example 4 Take 1 kg of the above-mentioned vanadium slag roasted clinker, add 4 L of water, then add a composite leaching agent and a composite reinforcing agent, and stir evenly to obtain the first slurry. The composite leaching agent is composed of citric acid, sulfuric acid, and sodium hypophosphite in a mass ratio of 2:8:1, and the amount added is 8% of the mass of the roasted clinker. The composite reinforcing agent is composed of trisodium mercaptotriazine (replacing sodium ethylenediamine dithiocarbamate), conventional polyacrylamide (replacing starch-grafted acrylamide copolymer), and sodium dodecylbenzenesulfonate in a mass ratio of 5:2:0.5, and the amount added is 1% of the mass of the roasted clinker. Adjust the pH of the first slurry to 3.0 using a 0.05 mol / L sulfuric acid solution, control the leaching temperature at 180℃, the stirring rate at 550 r / min, and the leaching time at 60 min to obtain the second slurry. Vacuum filter the second slurry to obtain a vanadium-containing leachate and leaching residue I. The leaching residue I was subjected to wet weak magnetic separation at a magnetic field strength of 1200 Oe to obtain iron concentrate and residual residue II. 3 L of water was added to residual residue II and stirred to prepare a third slurry. The pH was adjusted in stages using a 3 mol / L sodium hydroxide solution: first, the pH was adjusted to 6.8 to precipitate and recover aluminum hydroxide; then, the pH was adjusted to 9.2 to precipitate and recover manganese hydroxide; finally, the pH was adjusted to 11.2 to precipitate and recover magnesium hydroxide.

[0045] In this comparative example, the vanadium leaching rate was 98.05%, and the vanadium concentration in the resulting vanadium-containing leachate was 17.30 g / L, the iron ion concentration was 0.65 g / L, the manganese concentration was 0.42 g / L, the magnesium concentration was 0.28 g / L, and the aluminum concentration was 0.35 g / L; the TFe grade of the iron concentrate was 61.45%, the iron recovery rate was 86.02%, and the comprehensive recovery rate of manganese, magnesium, and aluminum was 83.15%.

[0046] Comparative Example 5 Take 1 kg of the above-mentioned vanadium slag roasted clinker, add 4 L of water, then add a composite leaching agent and a composite reinforcing agent, and stir evenly to obtain the first slurry. The composite leaching agent is composed of sulfuric acid and sodium hypophosphite in a mass ratio of 8:1 (without citric acid), and the amount added is 8% of the mass of the roasted clinker. The composite reinforcing agent is composed of sodium ethylenediamine dithiocarbamate, starch-grafted acrylamide copolymer, and sodium dodecylbenzenesulfonate in a mass ratio of 5:2:0.5, and the amount added is 1% of the mass of the roasted clinker. Adjust the pH of the first slurry to 3.0 using a 0.05 mol / L sulfuric acid solution, control the leaching temperature at 180℃, the stirring rate at 550 r / min, and the leaching time at 60 min to obtain the second slurry. Vacuum filter the second slurry to obtain a vanadium-containing leachate and leaching residue I. Wet weak magnetic separation is performed on leaching residue I under a magnetic field strength of 1200 Oe to obtain iron concentrate and residual residue II. Add 3 L of water to the remaining residue II and stir to prepare the third slurry. Use 3 mol / L sodium hydroxide solution to adjust the pH value in stages. First, adjust the pH to 6.8 to precipitate and recover aluminum hydroxide, then adjust the pH to 9.2 to precipitate and recover manganese hydroxide, and finally adjust the pH to 11.2 to precipitate and recover magnesium hydroxide.

[0047] In this comparative example, the vanadium leaching rate was 92.35%, and the vanadium concentration in the resulting vanadium-containing leachate was 16.30 g / L, the iron ion concentration was 0.15 g / L, the manganese concentration was 0.10 g / L, the magnesium concentration was 0.07 g / L, and the aluminum concentration was 0.08 g / L; the TFe grade of the iron concentrate was 61.85%, the iron recovery rate was 86.50%, and the comprehensive recovery rate of manganese, magnesium, and aluminum was 89.02%.

[0048] Comparative Example 6 Take 1 kg of the above-mentioned vanadium slag roasted clinker, add 4 L of water, then add a composite leaching agent and a composite reinforcing agent, and stir evenly to obtain the first slurry. The composite leaching agent is composed of citric acid, sulfuric acid, and sodium hypophosphite in a mass ratio of 2:8:1, and the amount added is 8% of the mass of the roasted clinker. The composite reinforcing agent is composed of sodium ethylenediamine dithiocarbamate, starch-grafted acrylamide copolymer, and sodium dodecylbenzenesulfonate in a mass ratio of 5:2:0.5, and the amount added is 1% of the mass of the roasted clinker. Adjust the pH of the first slurry to 3.0 using a 0.05 mol / L sulfuric acid solution, control the leaching temperature at 180℃, the stirring rate at 550 r / min, and the leaching time at 60 min to obtain the second slurry. Vacuum filter the second slurry to obtain vanadium-containing leachate and leaching residue I. This comparative example omits the magnetic separation for iron extraction and the classification and precipitation steps; leaching residue I is directly disposed of as tailings without recovery of iron, manganese, magnesium, or aluminum.

[0049] In this comparative example, the vanadium leaching rate was 99.72%, and the vanadium concentration in the resulting vanadium-containing leachate was 17.60 g / L, the iron ion concentration was 0.08 g / L, the manganese concentration was 0.04 g / L, the magnesium concentration was 0.03 g / L, and the aluminum concentration was 0.05 g / L.

Claims

1. A method for the complete resource utilization of vanadium slag, characterized in that, Includes the following steps: S1 Preparation of slurry: Water, composite leaching agent and composite strengthening agent are added to vanadium slag roasted clinker and mixed to obtain the first slurry; S2 Selective Leaching: The pH of the first pulp is adjusted to acidic, and a second pulp is obtained through a leaching reaction; S3 Solid-liquid separation: The second slurry is filtered and separated to obtain vanadium-containing leaching solution and leaching residue I; S4 Iron extraction: Separate leaching residue I to obtain iron concentrate and residual residue II; S5 Residue Pulping: Water is added to the remaining residue to obtain the third pulp; S6 graded sedimentation: The pH of the third slurry is adjusted by graded sedimentation, and manganese, magnesium and aluminum are recovered. The tailings are then treated for resource recovery.

2. The method for the complete resource utilization of vanadium slag according to claim 1, characterized in that, Vanadium slag includes at least one of the following: vanadium slag from vanadium-titanium magnetite smelting converters, vanadium tailings from coal stone extraction, vanadium slag from shale extraction, and vanadium-containing solid waste from chemical processing; and / or, vanadium slag roasted clinker includes at least one clinker or a mixture thereof obtained by vanadium slag roasting with sodium, calcification, oxidation, or composite additives.

3. The method for the complete resource utilization of vanadium slag according to claim 1, characterized in that, In S2, the pH of the first slurry is adjusted to 2.0-3.5, the leaching temperature is controlled at 120-180℃, the leaching time is 30-120 min, and the stirring rate is 300-800 r / min.

4. The method for the complete resource utilization of vanadium slag according to claim 1, characterized in that, In S3, the leaching residue is rinsed with a composite reinforcing agent aqueous solution with a mass concentration of 0.1%-0.5%, and the rinsing solution is incorporated into the vanadium-containing leaching solution.

5. The method for the complete resource utilization of vanadium slag according to claim 1, characterized in that, In S4, magnetic separation is used for separation, with a magnetic field strength of 800-1500 Oe.

6. The method for the complete resource utilization of vanadium slag according to claim 1, characterized in that, In S6, fractional precipitation is used: First stage: Adjust the pH value to 6.5-7.0 to precipitate and recover aluminum hydroxide; Second stage: Adjust the pH value to 9.0-9.5 to precipitate and recover manganese hydroxide; Third stage: Adjust the pH value to 11.0-11.5 and precipitate and recover magnesium hydroxide.

7. The method for the complete resource utilization of vanadium slag according to any one of claims 1 to 6, characterized in that, In S1, the composite leaching agent includes organic acid, inorganic acid, and reducing agent; the composite leaching agent includes at least one of features (1-1) to (1-5): (1-1) Organic acids include at least one of citric acid, oxalic acid, and tartaric acid; (1-2) Inorganic acids include at least one of sulfuric acid, hydrochloric acid, and nitric acid; (1-3) The reducing agent includes at least one of sodium hypophosphite, sodium sulfite, sodium phosphite, and ascorbic acid; (1-4) The mass ratio of organic acid, inorganic acid, and reducing agent is (1-3):(5-10):(0.5-2); (1-5) The amount of composite leaching agent added is 5%-12% of the mass of vanadium slag roasted clinker.

8. The method for the complete resource utilization of vanadium slag according to claim 7, characterized in that, In the composite leaching agent, the organic acid is citric acid, the inorganic acid is sulfuric acid, and the reducing agent is sodium hypophosphite. The mass ratio of the three is 2:8:

1. The amount of composite leaching agent added is 8%-10% of the mass of vanadium slag roasted clinker.

9. The method for the complete resource utilization of vanadium slag according to any one of claims 1 to 6, characterized in that, In S1, the composite reinforcing agent includes a chelating agent, a modified flocculant, and a dispersant; the composite reinforcing agent includes at least one of features (2-1) to (2-5): (2-1) The chelating agent includes at least one of sodium ethylenediamine dithiocarbamate, diethylenetriamine pentamethylphosphonic acid, and aminotrimethylenephosphonic acid; (2-2) Modified flocculants include at least one of starch-grafted acrylamide copolymer, carboxymethyl cellulose-grafted polyacrylamide, and chitosan-grafted acrylamide; (2-3) The dispersant includes at least one of sodium dodecylbenzene sulfonate, sodium lignosulfonate, and sodium polycarboxylate; (2-4) The mass ratio of chelating agent, modified flocculant and dispersant is (3-8):(1-3):(0.2-1); (2-5) The amount of composite reinforcing agent added is 0.5%-3% of the mass of vanadium slag roasted clinker.

10. The method for the complete resource utilization of vanadium slag according to claim 9, characterized in that, In the composite reinforcing agent, the chelating agent is sodium ethylenediamine dithiocarbamate, the modified flocculant is starch-grafted acrylamide copolymer, and the dispersant is sodium dodecylbenzenesulfonate. The mass ratio of the three is (4-6):2:0.5; and / or, the amount of composite reinforcing agent added is 1%-2% of the mass of vanadium slag roasted clinker.