A method for separating and extracting valuable components from vanadium slag

Abstract

The application discloses a method for separating, extracting and recovering valuable components in vanadium slag and relates to the technical field of comprehensive utilization of vanadium slag resources.The method comprises at least the following steps: S1, adding water, a leaching agent and a reinforcing agent into the vanadium slag to obtain a first ore pulp; S2, adjusting the pH value of the first ore pulp solution to perform leaching to obtain a second ore pulp; and S3, after the leaching is completed, adjusting the pH value of the second ore pulp and performing filtration separation to obtain a vanadium-containing filtrate and a residue.The leaching agent has single targeting selectivity for vanadium, and vanadium elements can be directionally dissolved in the vanadium slag leaching stage, and the remaining metals are synchronously precipitated with ligands to form crystal state complexes to realize one-step completion of "dissolving vanadium and retaining impurities".The stability of the metal complexes in the precipitated phase is significantly different, and only the pH value of the third ore pulp needs to be adjusted in stages to sequentially realize complex dissociation-reprecipitation, the step-by-step recovery of the impurity metals is completed, the impurity metals can be directly introduced into a subsequent vanadium precipitation process, and a dedusting unit does not need to be additionally arranged, so that the process is shortened, the energy consumption is reduced and the process economy is improved.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization technology of vanadium slag resources, specifically a method for separating, extracting and recovering valuable components from vanadium slag. Background Technology

[0002] Vanadium, hailed as a "metallic vitamin," is one of the very few engineering metals that excels in all four quadrants of strength, weight, temperature resistance, and corrosion resistance. Adding just 0.1% to steel can increase yield strength by over 30%. Its high-temperature alloys maintain a creep strength of ≥800 MPa even under 700°C gas scouring. As a sulfuric acid catalyst, V₂O₅ exhibits 1.5–2.3 times the conversion activity of any transition metal oxide. In vanadium redox flow batteries (VRFB), the reversibility of the tetravalent / pentavalent vanadium redox couple determines the energy storage system's cycle life of over 20 years. Due to its "small usage, high performance, and irreplaceable nature," the EU has listed it as a high-value commodity with an "economic importance of 10 / 10+ and supply risk of 8.5 / 10" in four consecutive editions of its Critical Raw Materials List, and has warned of a global secondary vanadium demand gap of 46,000–58,000 tons by 2030.

[0003] However, although my country accounts for 19% of the world's vanadium reserves and 68% of its production, over 90% of its vanadium production still relies on the sole industrial route established in the 1960s: "vanadium-titanium magnetite—converter vanadium slag—sodium / calcium roasting." Among these, the calcium roasted clinker obtained through calcium-based additive roasting and water quenching suffers from extremely high solubility due to the high lattice energy of calcium vanadate phases such as CaV₂O₆ and Ca₂V₂O₇ (above -3800 kJ·mol⁻¹). Under the commonly used industrial H₂SO₄ or (NH₄)₂CO₃-NH₃·H₂O system, the vanadium leaching rate has long been "locked" at a ceiling of 80% ± 4%. Even more challenging is the simultaneous leaching of impurities such as Cr, Mn, Si, and Al, whose concentrations can reach 15–30% of the vanadium concentration. If ammonium salts are added directly to precipitate vanadium, the aforementioned impurities will co-crystallize with ammonium polyvanadate, resulting in a V2O5 product purity of ≤98.5% obtained from downstream calcination, which cannot meet the requirements for aerospace-grade vanadium-aluminum master alloy (V2O5≥99.5%) and electrolyte-grade (V2O5≥99.9%).

[0004] While the traditional three-stage "leaching-purification-vanadium precipitation" process can remove impurities through chemical precipitation, solvent extraction, or ion exchange, it results in a 40-60% increase in process length, a 1.8-2.2-fold increase in acid and alkali consumption, a 5-8% loss in total vanadium recovery rate, and a more than 30% increase in hazardous waste residue. This raises the processing cost per ton of vanadium by 12,000-15,000 yuan, severely weakening the competitiveness of enterprises. Even more serious is the fact that every 1 ton of V₂O₅ produced is accompanied by 2.3-2.8 tons of hazardous waste residue (pH 11-12, Cr...). 6+With a vanadium content of 800–1200 mg·kg⁻¹, vanadium cannot be directly landfilled under the current Hazardous Waste Exemption List, leading to exponentially increasing environmental pressure. Therefore, developing a new "one-step selective leaching" technology to achieve efficient targeted leaching of vanadium from vanadium-burning slag while simultaneously shielding impurities has become an urgent priority to overcome the bottlenecks in the green, low-carbon, and high-end upgrading of my country's vanadium industry. Summary of the Invention

[0005] The purpose of this invention is to provide a method for separating, extracting and recovering valuable components from vanadium slag, thereby solving the technical problems of poor selectivity and low vanadium leaching rate in the acid leaching of vanadium slag in the prior art, which leads to complex and costly subsequent purification processes for impurities.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for separating, extracting, and recovering valuable components from vanadium slag, comprising at least the following steps:

[0007] S1: Water, leaching agent and strengthening agent are added to vanadium slag to obtain the first slurry;

[0008] S2: Adjust the pH value of the first slurry solution and perform leaching to obtain the second slurry;

[0009] S3: After leaching, adjust the pH of the second slurry and then filter and separate to obtain vanadium-containing filtrate and residue;

[0010] S4: Add water to the leaching residue and stir well to obtain the third slurry;

[0011] S5: Adjust the pH of the third slurry to dissolve the metal gradient of the complexed precipitate;

[0012] S6: Add the gradient disintegrating solution to the precipitant; stir evenly to obtain the fourth slurry;

[0013] S7: Adjust the pH of the fourth slurry and use gradient sedimentation to recover metal impurities.

[0014] Furthermore, the vanadium slag includes at least vanadium-titanium magnetite smelting slag, vanadium extraction slag from coal shale, vanadium slag from shale, or vanadium slag from other sources. The vanadium slag is vanadium slag obtained by direct smelting, vanadium slag obtained by calcification roasting, vanadium slag obtained by sodium roasting, vanadium slag obtained by roasting other transition metal oxides, or a mixture of multiple vanadium slag raw materials.

[0015] The vanadium slag comprises at least V2O5: 11-12wt%, Cr2O3: 1-3wt%, MnO: 2-4wt%, CaO: 5-7wt%, Al2O3: 2-5wt%, MgO: 8-12wt%, TiO2: 5-8wt%, SiO2: 21-30wt%, and Fe2O3: 21-43%.

[0016] The vanadium slag particles, ground to a size less than 0.07 mm, account for 80 wt%.

[0017] Furthermore, the leaching agent includes at least sulfuric acid, nitric acid, hydrochloric acid, acetic acid, oxalic acid, citric acid, ascorbic acid, hypochlorous acid, perchloric acid, nitrite, diethyldithiocarbamate, and polybasic mixed acids;

[0018] The concentration of the acid used in the leaching agent is 0.04 mol / L-0.06 mol / L;

[0019] The amount of leaching agent added is 5wt%-15wt% of the vanadium slag.

[0020] Further, the reinforcing agent is nitrite, diethyl dithiocarbamate or a mixture thereof, wherein the mass ratio of nitrite to diethyl dithiocarbamate is (1-25):1;

[0021] The nitrites include at least calcium nitrite, ammonium nitrite, nitrite, manganese nitrite, and magnesium nitrite, or a mixture of any two or more nitrites;

[0022] The diethyldithiocarbamate includes at least sodium diethyldithiocarbamate, calcium diethyldithiocarbamate, and ammonium diethyldithiocarbamate, or a mixture of any two or more nitrites, or a mixture of any one or more of the above reinforcing agents.

[0023] Furthermore, the pH value of the first slurry is adjusted to 1-5;

[0024] The pH of the second slurry is adjusted to 1-3;

[0025] After adjusting the pH value, stir and leach at 40~80℃ for 20~60min at a stirring rate of 400r / min~800r / min.

[0026] Further, the precipitant is composed of diethyl dithiocarbamate, iminodisuccinate and methylglycine diacetate, and the mass ratio of the components of diethyl dithiocarbamate, iminodisuccinate and methylglycine diacetate is (1-8):1:1;

[0027] The amount of precipitant added is 10wt%-15wt% of the mass of vanadium slag;

[0028] The diethyldithiocarbamate comprises at least sodium diethyldithiocarbamate, ammonium diethyldithiocarbamate, and magnesium diethyldithiocarbamate, or any mixture of two or more thereof.

[0029] The iminodisuccinate includes at least iminodisuccinic acid, tetrasodium iminodisuccinate, dimagnesium iminodisuccinate, or any mixture of two or more thereof;

[0030] The methylglycine salt comprises at least potassium methylglycine diacetate and ammonium methylglycine diacetate, or any mixture of two or more.

[0031] Furthermore, the pH value of the third slurry is adjusted to 1-7, and the pH value of the fourth slurry is adjusted to 1-7.

[0032] Furthermore, the residue separated by filtration includes at least one or a mixture of several of the following: anhydrous ethanol, acetone, deionized water, diethyldithiocarbamic acid, and methylglycine diacetate solution.

[0033] Furthermore, the residue separated by filtration is rinsed with a mixed solution of 0.01 mol / L sodium diethyldithiocarbamate and 0.03 mol / L trisodium methylglycine diacetate, wherein the mass ratio of each component in the mixed solution is 1:1.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] The leaching agent of this invention exhibits single-target selectivity for vanadium, enabling the directional dissolution of vanadium during the vanadium slag leaching stage. Simultaneously, other metals form crystalline complexes with the ligands, achieving a one-step "vanadium dissolution and impurity retention" process. The stability of the various metal complexes in the precipitate phase varies significantly; only a stepwise adjustment of the third slurry pH is needed to sequentially de-complex and reprecipitate, completing the stepwise recovery of impurity metals. This allows the precipitate to directly proceed to the subsequent vanadium precipitation process without the need for an additional impurity removal unit, thereby shortening the process, reducing energy consumption, and improving process economy. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart illustrating the overall steps of the present invention;

[0038] Figure 2 This is a schematic diagram of the framework of the present invention. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0040] Conventional vanadium slag leaching processes involve leaching, extraction to remove impurities, and precipitation to prepare high-purity vanadium pentoxide. This process, however, utilizes calcium nitrite-assisted sulfuric acid leaching. The HNO2 released from the decomposition of nitrite acts as a selective oxidant, oxidizing the vanadium in the dense Fe₂O₃-V₂O₃ solid solution. 3+ Oxidized to highly soluble VO2 + The leaching agent described in this invention exhibits single-target selectivity for vanadium, enabling the directional dissolution of vanadium element during the vanadium slag leaching stage. Consequently, the concentration of impurity ions in the resulting vanadium-containing leachate is below the detection limit, allowing it to directly proceed to the subsequent vanadium precipitation process without the need for an additional impurity removal unit. This shortens the process, reduces energy consumption, and improves process economy. Diethyldithiocarbamate instantaneously dissociates into CSS⁻ active groups in acidic slurry, precisely complexing with metallic impurities to form dense, uniformly sized M(DDTC)n precipitates, while VO₂... + Because their complexation constants are three orders of magnitude lower, they remain stable in the liquid phase; the complexes can be disentangled sequentially simply by switching pH gradients. The core mechanism of tetrasodium iminodisuccinate (IDS-Na4) and trisodium methylglycine diacetate (MGDA-Na3) precipitation of metal ions is a "chelation-dispersion-rechelation" cycle: both first coordinate with the imino group via polycarboxylate ions, locking the metal ions into stable water-soluble chelate rings and preventing them from continuing to grow as crystal nuclei; when the local supersaturation of the solution increases or the pH / temperature changes, the chelates already adsorbed on the surface of the nascent microcrystals peel off the microcrystals through double-layer repulsion, forming a negatively charged protective shell, preventing the crystals from growing and settling, thus achieving "precipitation inhibition"; if the concentration of metal ions continues to increase, the free chelating agent can re-chelate the released ions, thus maintaining the metal in the form of a soluble complex throughout the process. The addition of the CSS⁻ active group of sodium diethyldithiocarbamate can cause the released ions to precipitate gradient, thereby achieving precise gradient recovery of metal ions.

[0041] Specifically as follows:

[0042] Example 1:

[0043] like Figure 1 and Figure 2 As shown, the present invention provides a method for separating, extracting and recovering valuable components from vanadium slag, which includes the following steps:

[0044] S1: Water, leaching agent and strengthening agent are added to vanadium slag to obtain the first slurry;

[0045] S2: Adjust the pH value of the first slurry solution and perform leaching to obtain the second slurry;

[0046] S3: After leaching, adjust the pH of the second slurry and then filter and separate to obtain vanadium-containing filtrate and residue;

[0047] S4: Add water to the leaching residue and stir well to obtain the third slurry;

[0048] S5: Adjust the pH of the third slurry to dissolve the metal gradient of the complexed precipitate;

[0049] S6: Add the gradient disintegrating solution to the precipitant; stir evenly to obtain the fourth slurry;

[0050] S7: Adjust the pH of the fourth slurry and use gradient sedimentation to recover metal impurities.

[0051] In the vanadium slag clinker high-efficiency selective leaching vanadium extraction method according to the present invention, vanadium elements can be directionally dissolved in the vanadium slag leaching stage. The resulting vanadium-containing leachate can be directly entered into the subsequent vanadium precipitation process without the need to add a purification unit, thereby shortening the process, reducing energy consumption and improving process economy.

[0052] In some specific embodiments, before step S1, the method further includes: grinding the vanadium slag until the fraction with a particle size less than 0.07 mm accounts for more than 80 wt%. Specifically, the vanadium slag is ground using a ball mill. After grinding, the particle size of the vanadium slag is significantly reduced, and the specific surface area is greatly increased, thereby expanding the contact area between the solvent and the vanadium slag. During leaching, more target components such as vanadates can fully contact and react with the leaching agent, thereby accelerating the transfer of valuable elements such as vanadium into the solution.

[0053] Based on the above embodiments, the leaching agent is at least composed of nitrite or diethyldithiocarbamate or a mixture of various substances; preferably, the leaching agent includes 0.05 mol / L sulfuric acid and calcium nitrite, sodium diethyldithiocarbamate, and the mass ratio of calcium nitrite and sodium diethyldithiocarbamate is (1-25):1.

[0054] Sulfuric acid is a strong acid and can provide a large number of hydrogen ions in aqueous solution. During the leaching process, sulfuric acid can provide hydrogen ions to calcium nitrite, thus converting calcium nitrite into nitrous acid.

[0055] Calcium nitrite is a multifunctional chemical substance, primarily used as a high-efficiency additive in concrete. Under acidic conditions, it can be converted into nitrous acid, which in turn binds the vanadium in the dense Fe₂O₃-V₂O₃ solid solution. 3+ Oxidized to highly soluble VO2 + This also disrupts lattice stability, which is beneficial for vanadium leaching.

[0056] Sodium diethyldithiocarbamate is an excellent metal complexing agent. In acidic slurry, it instantly dissociates into CSS⁻ active groups, which precisely complex with metal impurities to form dense, uniformly sized M(DDTC)n precipitates. Meanwhile, VO2+ remains stably retained in the liquid phase due to its complexing constant being three orders of magnitude lower. By simply switching the pH gradient, the complexing and reprecipitation can be carried out sequentially, thereby achieving the stepwise recovery of impurity metals and ultimately obtaining ultra-high purity vanadium solution.

[0057] In some specific embodiments, the preferred mass ratio of sulfuric acid, calcium nitrite, and sodium diethyldithiocarbamate is 20:1:1.

[0058] While conventional vanadium slag extraction employs a three-stage process of "leaching-purification-vanadium precipitation," which utilizes chemical precipitation, solvent extraction, or ion exchange to remove impurities and ultimately precipitate vanadium to obtain V₂O₅, this invention utilizes a one-step selective leaching process. During the vanadium slag leaching process, calcium nitrite, through a triple synergistic mechanism of "oxidation-complexation-precipitation," becomes the core reagent for overcoming the bottleneck in vanadium leaching rate. First, the HNO₂ released from its acidic decomposition acts as a selective oxidant, precipitating V₂O₅ within the dense Fe₂O₃-V₂O₃ solid solution that encapsulates vanadium. 3+ Oxidized to highly soluble VO2 + This also disrupts lattice stability, exposing the physically encapsulated vanadium to the sulfuric acid medium; secondly, Ca... 2+ With SO4 2- The formation of CaSO4·2H2O precipitate not only eliminates the inhibitory effect of sulfate on vanadium dissolution (preventing the formation of a CaSO4 coating), but also generates microcracks within the particles through crystallization stress, expanding the sulfuric acid penetration channels. Simultaneously, a dense calcium sulfate passivation layer may form on the surface of the calcium vanadate mineral during acid leaching, hindering H2O penetration. + Inward diffusion and outward diffusion of vanadium. The generation and escape of nitrogen oxide gases can physically disturb and destroy this passivation film, opening channels for mass transfer between reactants and products, and significantly accelerating reaction kinetics. Sodium diethyldithiocarbamate instantaneously dissociates CSS⁻ active groups in acidic slurry, precisely complexing with metallic impurities to form dense, uniformly sized M(DDTC)n precipitates, while VO₂... +Because their complexation constants are three orders of magnitude lower, they remain stable in the liquid phase; the complexes can be disentangled sequentially simply by switching pH gradients. The core mechanism of tetrasodium iminodisuccinate (IDS-Na4) and trisodium methylglycine diacetate (MGDA-Na3) precipitation of metal ions is a "chelation-dispersion-rechelation" cycle: both first coordinate with the imino group via polycarboxylate ions, locking the metal ions into stable water-soluble chelate rings and preventing them from continuing to grow as crystal nuclei; when the local supersaturation of the solution increases or the pH / temperature changes, the chelates already adsorbed on the surface of the nascent microcrystals peel off the microcrystals through double-layer repulsion, forming a negatively charged protective shell, preventing the crystals from growing and settling, thus achieving "precipitation inhibition"; if the concentration of metal ions continues to increase, the free chelating agent can re-chelate the released ions, thus maintaining the metal in the form of a soluble complex throughout the process. The addition of the CSS⁻ active group of sodium diethyldithiocarbamate can cause the released ions to precipitate gradient, thereby achieving precise gradient recovery of metal ions. Therefore, this method is an efficient and economical leaching enhancement technique. The chemical reactions involved in the leaching process are as follows:

[0059] Fe2O3·V2O3+Ca(NO2)2+4H2SO4=Fe2(SO4)3+CaSO4·2H2O+2VO2 + +2NO + 2H2O

[0060] M n+ +nDDTC - →M(DDTC)n

[0061] Vanadium extraction from vanadium-titanium magnetite currently mainly employs the converter blowing and slag-making method to produce vanadium slag from blast furnace molten iron. This method utilizes the principle of selective oxidation, employing a high-speed pure oxygen jet to stir the vanadium-containing molten iron in the converter, oxidizing the vanadium in the molten iron into high-valence, stable vanadium oxides, thus obtaining vanadium slag. After roasting, the trivalent vanadium in the vanadium-iron spinel is converted into acid-soluble pentavalent vanadium compounds, which can be efficiently dissolved in a sulfuric acid solution. After impurity removal from the vanadium-containing leachate, separation can be achieved through cooling crystallization to obtain the vanadium product.

[0062] Based on the above embodiments, the amount of leaching agent added is 5-15 wt% of the vanadium slag. Preferably, the amount of leaching agent added is 10 wt% of the vanadium slag.

[0063] In some specific embodiments, the pH value of the first slurry solution is preferably adjusted to 1-5, and more preferably the pH value of the first slurry solution is 3.

[0064] In some specific embodiments, the pH value of the second slurry solution is preferably adjusted to 1-3, and more preferably the pH value of the second slurry solution is 1.

[0065] In some specific embodiments, the precipitant is composed of sodium diethyldithiocarbamate, tetrasodium iminodisuccinate, and trisodium methylglycine diacetate.

[0066] In some specific embodiments, the precipitant is sodium diethyldithiocarbamate, tetrasodium iminodisuccinate, and trisodium methylglycine diacetate, with a preferred mass ratio of (1-8):1:1.

[0067] In some specific embodiments, the amount of precipitant added is approximately 10-15 wt% of the vanadium slag. Preferably, it is 12 wt% of the vanadium slag.

[0068] In some specific embodiments, adjusting the pH of the slurry involves adding an acidic or alkaline solution to adjust the pH, followed by stirring and leaching at 40–80°C for 20–60 minutes. For example, a 0.01 mol / L ammonia solution or a 0.01 mol / L H₂SO₄ solution can be used to adjust the pH of the slurry. Preferably, stirring and leaching is performed at 60°C for 40 minutes.

[0069] In some specific embodiments, the residue separated by filtration is washed with a mixed solution of 0.01 mol / L sodium diethyldithiocarbamate and 0.03 mol / L trisodium methylglycine diacetate.

[0070] In some specific embodiments, the mass ratio of the filtered residue to a mixed solution of 0.01 mol / L sodium diethyldithiocarbamate and 0.03 mol / L trisodium methylglycine diacetate is preferably 1:1.

[0071] Based on the above embodiments, the predetermined leaching conditions include a leaching stirring rate ranging from 400 to 800 r / min. Preferably, the stirring speed is 600 r / min.

[0072] In summary

[0073] This invention discloses a method for separating, extracting, and recovering valuable components from vanadium slag, which solves the technical problems of low vanadium leaching rate and poor acid leaching selectivity in existing vanadium slag materials, leading to complex and costly subsequent impurity purification processes. The method includes adding a leaching agent to the vanadium slag material, adjusting the pH of the first slurry, performing leaching, and finally separating the solid and liquid components of the slurry after leaching through solid-liquid filtration, gradient sedimentation, and precise recovery. The leaching agent is a mixture of calcium nitrite and sulfuric acid in a specific ratio.

[0074] The precipitant is composed of sodium diethyldithiocarbamate, tetrasodium iminodisuccinate, and trisodium methylglycine diacetate in a specific ratio.

[0075] The vanadium leaching rate of this invention is greater than 99.6%, and the vanadium concentration in the resulting vanadium-containing leachate is about 40-48 g / L. The Cr recovery rate is 98.7%, the Mn recovery rate is 96%, the Al recovery rate is 97.7%, the Mg recovery rate is 92.1%, the Ti recovery rate is 95.9%, and the Si recovery rate is 88.4%.

[0076] Example 2:

[0077] The vanadium slag contains 11.2 wt% V₂O₅, 3 wt% Cr₂O₃, 9 wt% MnO, 5 wt% Al₂O₃, 6 wt% MgO, 8 wt% TiO₂, 28 wt% SiO₂, 6 wt% CaO, and 23.8 wt% Fe₂O₃. The vanadium slag is ground until 80 wt% of particles are smaller than 0.070 mm to obtain finely ground clinker. 0.2 kg of the finely ground clinker is added to 1 L of water, followed by a leaching agent. The preferred mass ratio of sulfuric acid, calcium nitrite, and sodium diethyldithiocarbamate in the leaching agent is 20:1:1. The amount of leaching agent added is 5 wt% of the finely ground clinker to obtain the first slurry. The pH of the slurry is adjusted to 3, and then stirred at 60℃ for 40 min to obtain the second slurry. The leaching stirring rate is 600 r / min. The pH of the third slurry was adjusted to 1, and a precipitant consisting of sodium diethyldithiocarbamate, tetrasodium iminodisuccinate, and trisodium methylglycine diacetate in a preferred mass ratio of 2:1:1 was added; the amount of precipitant added was 12 wt% of the vanadium slag clinker. This process dissociated the complexed precipitate of metals, followed by gradient precipitation. After the reaction, the mixture was filtered stepwise to obtain a vanadium-containing leachate and leaching residues of various metals.

[0078] In this embodiment, the leaching rate of vanadium is 99.65%, the recovery rate of Cr is 98.7%, the recovery rate of Mn is 96%, the recovery rate of Al is 97.7%, the recovery rate of Mg is 92.1%, the recovery rate of Ti is 95.9%, and the recovery rate of Si is 88.4%.

[0079] Example 3:

[0080] The vanadium slag contained 12.2 wt% V₂O₅, 2 wt% Cr₂O₃, 7 wt% MnO, 6 wt% Al₂O₃, 6 wt% MgO, 9 wt% TiO₂, 27 wt% SiO₂, 6 wt% CaO, and 24.8 wt% Fe₂O₃. The vanadium slag was ground until 80 wt% of particles were smaller than 0.070 mm, yielding finely ground clinker. 0.2 kg of the finely ground clinker was added to 1 L of water, followed by the addition of a leaching agent containing sulfuric acid. The amount of leaching agent added was 5 wt% of the finely ground clinker, yielding the first slurry. The pH of the slurry was adjusted, and ammonium sulfate, a precipitant, was added at 10 wt% of the vanadium slag clinker. The mixture was filtered and washed to obtain a vanadium-containing precipitate.

[0081] In this embodiment, the vanadium leaching rate was 84.07%.

[0082] Example 4:

[0083] The vanadium slag clinker contains 13.5 wt% V₂O₅, 2.5 wt% Cr₂O₃, 8.5 wt% MnO, 4.6 wt% Al₂O₃, 11.6 wt% MgO, 7.5 wt% TiO₂, 4 wt% CaO, 33.8 wt% Fe₂O, and 14 wt% SiO₂. The vanadium slag clinker is ground until 88 wt% of particles are smaller than 0.070 mm, yielding finely ground clinker. 0.2 kg of the finely ground clinker is added to 1 L of water, followed by a leaching agent. The preferred mass ratio of hydrochloric acid, calcium nitrite, and sodium diethyldithiocarbamate in the leaching agent is 20:3:1. The amount of leaching agent added is 5 wt% of the finely ground clinker, yielding the first slurry. The pH of the slurry is adjusted to 3, and then stirred at 60℃ for 60 min to obtain the second slurry. The leaching stirring rate is 600 r / min. The pH of the third slurry was adjusted to 1, and a precipitant consisting of sodium diethyldithiocarbamate, sodium iminodisuccinate, and trisodium methylglycine diacetate in a preferred mass ratio of 2:1:1 was added; the amount of precipitant added was 12 wt% of the vanadium slag clinker. This process dissociated the complexed precipitate of metals, followed by gradient precipitation. After the reaction, the mixture was filtered stepwise to obtain a vanadium-containing leachate and leaching residues of various metals.

[0084] In this embodiment, the leaching rate of vanadium is 99.68%, the recovery rate of Cr is 99.1%, the recovery rate of Mn is 96.3%, the recovery rate of Al is 97.6%, the recovery rate of Mg is 92.5%, the recovery rate of Ti is 95.8%, and the recovery rate of Si is 86.4%.

[0085] Example 5:

[0086] The vanadium slag contains 12.6 wt% V₂O₅, 2.75 wt% Cr₂O₃, 9.32 wt% MnO, 4.15 wt% Al₂O₃, 10.78 wt% MgO, 7.2 wt% TiO₂, 4 wt% CaO, 38.8 wt% Fe₂O₃, and 10.4 wt% SiO₂. The vanadium slag is ground until particles smaller than 0.070 mm account for 75 wt%, yielding a finely ground material. 0.2 kg of the finely ground material is added to 1 L of water, followed by a leaching agent. The preferred mass ratio of citric acid, sodium nitrite, and potassium diethyldithiocarbamate in the leaching agent is 20:1:1. The amount of leaching agent added is 10 wt% of the ground clinker, yielding the first slurry. The pH of the slurry is adjusted to 3, and then stirred at 65°C for 20 min to obtain the second slurry. The leaching stirring rate is 600 r / min. The pH of the third slurry was adjusted to 1, and a precipitant consisting of sodium diethyldithiocarbamate and tetrasodium iminodisuccinate in a preferred mass ratio of 2:1 was added; the amount of precipitant added was 8 wt% of the vanadium slag clinker. This process de-complexed the metals in the precipitate, followed by gradient precipitation. After the reaction, the mixture was filtered stepwise to obtain a vanadium-containing leachate and leaching residues of various metals.

[0087] In this embodiment, the leaching rate of vanadium is 93.95%, the recovery rate of Cr is 95.3%, the recovery rate of Mn is 92.7%, the recovery rate of Al is 91.4%, the recovery rate of Mg is 88.1%, the recovery rate of Ti is 90.1%, and the recovery rate of Si is 84.2%.

[0088] Example 6:

[0089] The vanadium slag contains 11.78 wt% V₂O₅, 3.16 wt% Cr₂O₃, 8.65 wt% MnO, 5.26 wt% Al₂O₃, 11.75 wt% MgO, 6.35 wt% TiO₂, 3 wt% CaO, 36.78 wt% Fe₂O₃, and 13.27 wt% SiO₂. The vanadium slag is ground until particles smaller than 0.070 mm account for 82 wt%, yielding a finely ground material. 0.2 kg of the finely ground material is added to 1 L of water, followed by a leaching agent. The preferred mass ratio of hydrochloric acid, calcium nitrite, and sodium diethyldithiocarbamate in the leaching agent is 20:1:2. The amount of leaching agent added is 7.5 wt% of the finely ground material, yielding the first slurry. The pH of the slurry is adjusted to 3, and then stirred at 80℃ for 40 min to obtain the second slurry. The leaching stirring rate is 750 r / min. The pH of the third slurry was adjusted to 1, and a precipitant consisting of ammonium diethyldithiocarbamate, magnesium iminodisuccinate, and trisodium methylglycine diacetate in a preferred mass ratio of 2:2:1 was added; the amount of precipitant added was 12 wt% of the vanadium slag clinker. This process dissociated the complexed precipitate of metals, followed by gradient precipitation. After the reaction, the mixture was filtered stepwise to obtain a vanadium-containing leachate and leaching residues of various metals.

[0090] In this embodiment, the leaching rate of vanadium was 98.15%, the recovery rate of Cr was 96.9%, the recovery rate of Mn was 96.8%, the recovery rate of Al was 96.8%, the recovery rate of Mg was 92.7%, the recovery rate of Ti was 94.6%, and the recovery rate of Si was 87.9%.

[0091] Example 7:

[0092] The vanadium slag contains 10.88 wt% V₂O₅, 2.95 wt% Cr₂O₃, 8.37 wt% MnO, 4.62 wt% Al₂O₃, 11.64 wt% MgO, 8.22 wt% TiO₂, 3.7 wt% CaO, 39.14 wt% Fe₂O₃, and 10.5 wt% SiO₂. The vanadium slag clinker is ground until 80 wt% of particles are smaller than 0.070 mm, yielding a finely ground material. 0.2 kg of the finely ground material is added to 1 L of water, followed by a leaching agent. The preferred mass ratio of oxalic acid, calcium nitrite, and potassium diethyldithiocarbamate in the leaching agent is 15:2:1. The leaching agent is added at 6 wt% of the finely ground material to obtain the first slurry. The pH of the slurry is adjusted to 3, and then stirred at 50°C for 60 min to obtain the second slurry. The leaching stirring rate is 600 r / min. The pH of the third slurry was adjusted to 1, and a precipitant consisting of ammonium methylglycine diacetate, tetrasodium iminodisuccinate, and trisodium methylglycine diacetate in a preferred mass ratio of 1:1:1 was added; the amount of precipitant added was 15 wt% of the vanadium slag clinker. This process dissociated the complexed precipitate of metals, followed by gradient precipitation. After the reaction, the mixture was filtered stepwise to obtain a vanadium-containing leachate and leaching residues of various metals.

[0093] In this embodiment, the leaching rate of vanadium was 91.09%, the recovery rate of Cr was 91.9%, the recovery rate of Mn was 89.7%, the recovery rate of Al was 90%, the recovery rate of Mg was 84.7%, the recovery rate of Ti was 86.9%, and the recovery rate of Si was 81.4%.

[0094] Example 8:

[0095] The vanadium slag contains 11.2 wt% V₂O₅, 3 wt% Cr₂O₃, 9 wt% MnO, 5 wt% Al₂O₃, 12 wt% MgO, 8 wt% TiO₂, 3 wt% CaO, 34 wt% Fe₂O₃, and 14.8 wt% SiO₂. The vanadium slag is ground until 80 wt% of particles are smaller than 0.070 mm, yielding a finely ground material. 0.2 kg of the finely ground material is added to 1 L of water, followed by a leaching agent. The preferred mass ratio of sulfuric acid, calcium nitrite, and sodium diethyldithiocarbamate in the leaching agent is 10:1:1. The leaching agent is added at 8 wt% of the finely ground material to obtain the first slurry. The pH of the slurry is adjusted to 3, and then stirred at 65°C for 80 min to obtain the second slurry. The leaching stirring rate is 600 r / min. The pH of the third slurry was adjusted to 3, and a precipitant consisting of potassium diethyldithiocarbamate, tetrapotassium iminodisuccinate, and tripotassium methylglycine diacetate in a preferred mass ratio of 3:2:1 was added; the amount of precipitant added was 12 wt% of the vanadium slag clinker. This process dissociated the complexed precipitate of metals, followed by gradient precipitation. After the reaction, the mixture was filtered stepwise to obtain a vanadium-containing leachate and leaching residues of various metals.

[0096] In this embodiment, the leaching rate of vanadium was 93.95%, the recovery rate of Cr was 89.3%, the recovery rate of Mn was 82.4%, the recovery rate of Al was 83.9%, the recovery rate of Mg was 79.2%, the recovery rate of Ti was 86%, and the recovery rate of Si was 80.7%.

[0097] Example 9:

[0098] The vanadium slag clinker contains 13.2 wt% V₂O₅, 2 wt% Cr₂O₃, 7 wt% MnO, 6 wt% Al₂O₃, 11.5 wt% MgO, 9.5 wt% TiO₂, 3 wt% CaO, 34 wt% Fe₂O₃, and 14.8 wt% SiO₂. The vanadium slag clinker is ground until 80 wt% of particles are smaller than 0.070 mm, yielding finely ground clinker. 0.2 kg of the finely ground clinker is added to 1 L of water, followed by a leaching agent. The preferred mass ratio of nitric acid, calcium nitrite, and ammonium diethyldithiocarbamate in the leaching agent is 30:1:1. The amount of leaching agent added is 5 wt% of the finely ground clinker, yielding the first slurry. The pH of the slurry is adjusted to 1, and then stirred at 75°C for 40 min to obtain the second slurry. The leaching stirring rate is 600 r / min. The pH of the third slurry was adjusted to 1, and a precipitant consisting of magnesium iminodisuccinate, diethyldithiocarbamate, and tripotassium methylglycine diacetate in a preferred mass ratio of 5:1:1 was added; the amount of precipitant added was 8 wt% of the vanadium slag clinker. This process de-complexed the precipitated metals, followed by gradient precipitation. After the reaction, the mixture was filtered stepwise to obtain a vanadium-containing leachate and leaching residues of various metals.

[0099] In this embodiment, the leaching rate of vanadium is 99.56%, the recovery rate of Cr is 98.9%, the recovery rate of Mn is 95.6%, the recovery rate of Al is 96.9%, the recovery rate of Mg is 92.7%, the recovery rate of Ti is 93.7%, and the recovery rate of Si is 90.6%.

[0100] Example 10:

[0101] The vanadium slag clinker contains 13.2 wt% V₂O₅, 2 wt% Cr₂O₃, 6 wt% MnO, 9 wt% Al₂O₃, 11 wt% MgO, 7 wt% TiO₂, 4 wt% CaO, 34 wt% Fe₂O₃, and 13.8 wt% SiO₂. The vanadium slag clinker is ground until 80 wt% of particles are smaller than 0.070 mm, yielding finely ground clinker. 0.2 kg of the finely ground clinker is added to 1 L of water, followed by a leaching agent. The preferred mass ratio of sulfuric acid, calcium nitrite, and sodium diethyldithiocarbamate in the leaching agent is 20:1:1. The amount of leaching agent added is 5 wt% of the finely ground clinker, yielding the first slurry. The pH of the slurry is adjusted to 5, and then stirred at 70℃ for 40 min to obtain the second slurry. The leaching stirring rate is 800 r / min. The pH of the third slurry was adjusted to 1, and a precipitant consisting of sodium diethyldithiocarbamate, tetrasodium iminodisuccinate, and trisodium methylglycine diacetate in a preferred mass ratio of 2:1:1 was added; the amount of precipitant added was 10 wt% of the vanadium slag clinker. This process dissociated the complexed precipitate of metals, followed by gradient precipitation. After the reaction, the mixture was filtered stepwise to obtain a vanadium-containing leachate and leaching residues of various metals.

[0102] In this embodiment, the leaching rate of vanadium is 86.05%, the recovery rate of Cr is 92.6%, the recovery rate of Mn is 93.5%, the recovery rate of Al is 93.8%, the recovery rate of Mg is 91.2%, the recovery rate of Ti is 92.7%, and the recovery rate of Si is 87.3%.

[0103] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for separating, extracting, and recovering valuable components from vanadium slag, characterized in that: At least the following steps are included: S1: Water, leaching agent and strengthening agent are added to vanadium slag to obtain the first slurry; The leaching agent includes one of sulfuric acid, nitric acid, hydrochloric acid, acetic acid, oxalic acid, citric acid, ascorbic acid, hypochlorous acid, perchloric acid, nitrite, diethyldithiocarbamate, and polybasic mixed acids; The concentration of the acid used in the leaching agent is 0.04 mol / L-0.06 mol / L; The amount of leaching agent added is 5wt%-15wt% of the vanadium slag; The reinforcing agent is nitrite, diethyldithiocarbamate or a mixture thereof, wherein the mass ratio of nitrite to diethyldithiocarbamate in the mixture is (1-25):1; The nitrite includes one of calcium nitrite, ammonium nitrite, nitrite, manganese nitrite, and magnesium nitrite; The diethyldithiocarbamate includes one of sodium diethyldithiocarbamate, calcium diethyldithiocarbamate, and ammonium diethyldithiocarbamate. S2: Adjust the pH value of the first slurry solution and perform leaching to obtain the second slurry; S3: After leaching, adjust the pH of the second slurry and then filter and separate to obtain vanadium-containing filtrate and residue; S4: Add water to the leaching residue obtained in S3, stir evenly to obtain the third slurry; S5: Adjust the pH of the third slurry to dissolve the metal gradient of the complexed precipitate; S6: Add the gradient disintegrating solution to the precipitant; stir evenly to obtain the fourth slurry; The precipitant is composed of diethyl dithiocarbamate, iminodisuccinate and methylglycine diacetate, and the mass ratio of the components of diethyl dithiocarbamate, iminodisuccinate and methylglycine diacetate is (1-8):1:

1. The amount of precipitant added is 10wt%-15wt% of the mass of vanadium slag; The diethyldithiocarbamate includes one of sodium diethyldithiocarbamate, ammonium diethyldithiocarbamate, and magnesium diethyldithiocarbamate. The iminodisuccinate includes one of iminodisuccinic acid, tetrasodium iminodisuccinate, and magnesium iminodisuccinate. The methylglycine diacetate includes one of potassium methylglycine diacetate and ammonium methylglycine diacetate; S7: Adjust the pH of the fourth slurry and use gradient sedimentation to recover metal impurities.

2. The method for separating, extracting, and recovering valuable components from vanadium slag according to claim 1, characterized in that: The vanadium slag mentioned includes one of the following: vanadium-titanium magnetite smelting slag, vanadium extraction slag from coal shale, vanadium slag from shale, or vanadium slag from other sources; The vanadium slag comprises at least V2O5: 11-12wt%, Cr2O3: 1-3wt%, MnO: 2-4wt%, CaO: 5-7wt%, Al2O3: 2-5wt%, MgO: 8-12wt%, TiO2: 5-8wt%, SiO2: 21-30wt%, and Fe2O3: 21-43%. The portion of the vanadium slag with particles ground to a size of less than 0.07 mm accounts for 80 wt%.

3. The method for separating, extracting, and recovering valuable components from vanadium slag according to claim 1, characterized in that: The pH value of the first slurry is adjusted to 1-5; The pH of the second slurry is adjusted to 1-3; After adjusting the pH value, stir and leach at 40~80℃ for 20~60min at a stirring rate of 400r / min~800r / min.

4. The method for separating, extracting, and recovering valuable components from vanadium slag according to claim 1, characterized in that: The pH value of the third slurry is adjusted to 1-7, and the pH value of the fourth slurry is adjusted to 1-7.

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