Method for separating, extracting and recycling valuable components in vanadium slag

Abstract

The invention discloses a method for separating, extracting and recycling valuable components in vanadium slag, and relates to the technical field of comprehensive utilization of vanadium slag resources. The method at least comprises the following steps that S1, water, a leaching agent and an enhancer are added into the vanadium slag, and first ore pulp is obtained; s2, the pH value of the first ore pulp solution is adjusted, leaching is conducted, and second ore pulp is obtained; and S3, after leaching is completed, the pH of the second ore pulp is adjusted, then filtering separation is conducted, and vanadium-containing filtrate and residues are obtained. The leaching agent has single targeted selectivity on vanadium, vanadium elements can be directionally dissolved out in the vanadium slag leaching stage, crystalline complex precipitates are synchronously formed by other metals and ligands, and vanadium dissolving and impurity retaining are completed in one step. The stability difference of all metal complexes in a precipitation phase is obvious, decomplexing-re-precipitation can be sequentially carried out only by adjusting the pH of the third ore pulp step by step, step-by-step recovery of impurity metal is completed, the subsequent vanadium precipitation process can be directly carried out, an impurity removal unit does not need to be additionally arranged, and therefore the process is shortened, the energy consumption is reduced, and the process economical efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of comprehensive utilization of vanadium slag resources, in particular to a method for separating and extracting valuable components from vanadium slag. BACKGROUND

[0002] Vanadium, known as "metallic vitamin", is one of the few engineering metals that can simultaneously pull the four quadrants of "strength-weight-corrosion-temperature" to the full: only 0.1% needs to be added to steel to increase the yield strength by more than 30%; under the gas scouring at 700°C, the high-temperature alloy can still maintain a holding strength of ≥800MPa; as a sulfuric acid catalyst, the conversion activity of V2O5 is 1.5-2.3 times that of any transition metal oxide; and in the all-vanadium redox flow battery (VRFB), the reversibility of the vanadium ion pair determines the 20-year cycle life of the energy storage system. Because of "small dosage, huge performance, and no alternative", the EU has listed it as a "double-high variety" with "economic importance 10 / 10 + supply risk 8.5 / 10" in the four versions of "key raw material list", and warned that the global secondary vanadium demand gap will reach 46-58 thousand tons in 2030.

[0003] However, although China accounts for 19% of global vanadium reserves and 68% of global vanadium production, more than 90% of vanadium still relies on the only industrial route formed in the 1960s, "vanadium-titanium magnetite-converter vanadium slag-sodium / calcium roasting". Among them, the calcified roasting clinker obtained by calcium additive roasting-water quenching, because the calcium vanadate phase lattice energy of CaV2O6, Ca2V2O7, etc. is as high as more than -3800kJ·mol-1, the dissolution inertia is great, and in the H2SO4 or (NH4)2CO3-NH3·H2O system commonly used in industry, the vanadium leaching rate has been "locked" at 80%±4% "ceiling" for a long time; more troublesome is that Cr, Mn, Si, Al and other impurities are also dissolved at the same time, and their concentration can reach 15-30% of the vanadium concentration. If ammonium salt is directly added to precipitate vanadium, the above impurities will co-crystallize with ammonium polyvanadate, resulting in V2O5 products with a purity of ≤98.5% obtained by calcination downstream, which cannot meet the requirements of aerospace-grade vanadium-aluminum intermediate alloy (V2O5≥99.5%) and electrolyte grade (V2O5≥99.9%).

[0004] Although the traditional "leaching-purification-vanadium precipitation" three-stage process can remove impurities by chemical precipitation, solvent extraction or ion exchange, it prolongs the process by 40-60%, increases acid and alkali consumption by 1.8-2.2 times, further reduces the total vanadium recovery rate by 5-8%, and increases the amount of hazardous waste slag by more than 30%, which increases the processing cost of per ton of vanadium by 12-15 thousand yuan, seriously weakening the competitiveness of enterprises. More seriously, for every 1t of V2O5 produced, 2.3-2.8t of hazardous waste slag (pH 11-12, Cr 6+800-1200mg·kg⁻¹), which cannot be directly landfilled according to the current "Hazardous Waste Exemption List", and the environmental protection pressure is exponentially enlarged. Therefore, it is urgent to develop a new "one-step selective leaching" technology to realize the efficient targeted dissolution of vanadium in vanadium slag and the synchronous shielding of impurities, which has become a top priority to break through the bottleneck of green low-carbon and high-end upgrading of China's vanadium industry. SUMMARY

[0005] The purpose of the present application is to provide a method for separating, extracting and recovering valuable components in vanadium slag, which solves the technical problems of poor selectivity of vanadium slag acid leaching, low vanadium leaching rate in the prior art, resulting in complex and high-cost purification process of impurities.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a method for separating, extracting and recovering valuable components in vanadium slag, at least comprising the following steps:

[0007] S1: adding water, leaching agent and intensifier into the vanadium slag to obtain a first ore slurry;

[0008] S2: adjusting the pH value of the first ore slurry solution, leaching, and obtaining a second ore slurry;

[0009] S3: after leaching is completed, adjusting the pH value of the second ore slurry, and then filtering and separating to obtain a vanadium-containing filtrate and a residue;

[0010] S4: adding water to the residue for re-leaching, and obtaining a third ore slurry after uniform stirring;

[0011] S5: adjusting the pH value of the third ore slurry to make the metal gradient of complex precipitation decomplex;

[0012] S6: adding a precipitating agent to the decomplexed solution, and obtaining a fourth ore slurry after uniform stirring;

[0013] S7: adjusting the pH value of the fourth ore slurry to gradient precipitate and recover metal impurities.

[0014] Further, the vanadium slag at least includes vanadium-titanium magnetite smelting slag, stone coal vanadium extraction slag, shale vanadium generated vanadium slag or other sources of vanadium slag, and the vanadium slag is directly smelted vanadium slag, calcified roasting obtained vanadium slag, sodium roasting obtained vanadium slag, other transition metal oxide roasting obtained vanadium slag or a mixture of a plurality of vanadium slag raw materials;

[0015] The composition of the vanadium slag at least includes 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: 21-43wt%;

[0016] The size of the vanadium slag is ground to a particle size of less than 0.07 mm, and the size of the ground vanadium slag is 80 wt%.

[0017] Further, the leaching agent comprises at least sulfuric acid, nitric acid, hydrochloric acid, acetic acid, oxalic acid, citric acid, ascorbic acid, hypochlorous acid, perchloric acid, nitrite, diethyldithiocarbamate and a multi-component mixed acid;

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

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

[0020] Further, the strengthening agent is nitrite, diethyldithiocarbamate or a mixture thereof, and the mass ratio of the nitrite to the diethyldithiocarbamate is (1-25):1;

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

[0022] The diethyldithiocarbamate comprises 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 strengthening agents.

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

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

[0025] After adjusting the pH value, the leaching is carried out at 40-80°C for 20-60 min under stirring at a stirring rate of 400 r / min-800 r / min.

[0026] Further, the precipitant is composed of diethyldithiocarbamate, iminodisuccinate and methylglycinediacetate, and the mass ratio of the components of the diethyldithiocarbamate, iminodisuccinate and methylglycinediacetate is (1-8):1:1;

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

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

[0029] The imino disuccinate at least includes imino disuccinic acid, imino disuccinic acid tetrasodium, imino disuccinic acid dimagnesium, or a mixture of any two or more thereof.

[0030] The methyl glycine salt at least includes potassium methyl glycine diacetate and ammonium methyl glycine diacetate, or a mixture of any two or more thereof.

[0031] Further, 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] Further, the residue separated by filtration at least includes one or a mixture of several of anhydrous ethanol, acetone, deionized water, diethyl dithio carbamic acid, and methyl glycine diacetate salt solution.

[0033] Further, the residue separated by filtration is rinsed with a mixed solution of 0.01 mol / L sodium diethyl dithio carbamate and 0.03 mol / L trisodium methyl glycine diacetate, and the mass ratio of the components in the mixed solution is 1:1.

[0034] Compared with the prior art, the present application has the following beneficial effects:

[0035] The leaching agent of the present application has single targeting selectivity for vanadium, and in the vanadium slag leaching stage, vanadium elements can be directionally dissolved, and the remaining metals are simultaneously precipitated with ligands to form crystalline complexes, so that the step of "dissolving vanadium and retaining impurities" is completed in one step. The stability of each metal complex in the precipitated phase differs significantly, and only the pH of the third slurry needs to be adjusted in stages to sequentially decomplex and re-precipitate, so that the step-by-step recovery of impurity metals is completed, and the process can directly enter the subsequent vanadium precipitation process without the need to add a metal removal unit, thereby shortening the process, reducing energy consumption, and improving process economy. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0037] Figure 1 The step flow chart of the present application as a whole;

[0038] Figure 2 The frame diagram of the present application. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application.

[0040] The conventional vanadium slag leaching process is through steps of leaching, impurity removal by extraction, precipitation and the like to prepare high-purity vanadium pentoxide, while the process utilizes calcium nitrite assisted sulfuric acid leaching, and HNO2 released by decomposition of nitrite is used as a selective oxidant to oxidize V in dense Fe2O3-V2O3 solid solution wrapping vanadium into high-solubility VO2 3+ + The leaching agent has single targeting selectivity for vanadium, and vanadium elements can be directionally dissolved in the vanadium slag leaching stage, so that the impurity ion concentration in the obtained vanadium-containing leaching solution is lower than the lower limit of detection, and the vanadium-containing leaching solution can directly enter a subsequent vanadium precipitation process without the need to additionally add an impurity removal unit, thereby shortening the process, reducing energy consumption and improving process economy. Diethyldithiocarbamate instantaneously dissociates CSS⁻ active groups in an acid pulp, and precisely complexes with metal impurities to generate M(DDTC)n precipitates which are dense in crystal form and uniform in particle size, while VO2 + is still stably retained in the liquid phase due to a low complexation constant of three orders of magnitude; and the complexation can be sequentially released only by switching a pH gradient; the core mechanism of imino disuccinic acid tetrasodium (IDS-Na4) and methyl glycine diacetic acid trisodium (MGDA-Na3) for precipitating metal ions is a "chelation-dispersion-rechelation" cycle: both of them are first coordinated with polycarboxylate and imino to lock metal ions into a stable water-soluble chelate ring to prevent the metal ions from continuing to grow as crystal nuclei; when local supersaturation of the solution increases or pH / temperature changes, the chelate adsorbed on the surface of the nascent microcrystal is stripped off by double electric layer repulsion to form a negative charge protective shell, so that the crystal cannot grow and settle, and "precipitation inhibition" is achieved; if the concentration of metal ions continues to increase, the free chelating agent can recomplex the released ions, so that the metal ions always exist in the form of soluble complexes throughout the process. The CSS⁻ active groups of added diethyldithiocarbamate sodium can make the released ions gradient precipitate, thereby realizing gradient precise recovery of the metal ions.

[0041] Specifically as follows:

[0042] Embodiment one:

[0043] As shown in Figure 1 and Figure 2 , the present application provides a method for separating, extracting and recovering valuable components in vanadium slag, which comprises the following steps:

[0044] S1: adding water, a leaching agent and a strengthening agent into the vanadium slag to obtain a first pulp;

[0045] ​S2: adjusting pH value of the first ore pulp, leaching to obtain a second ore pulp;

[0046] S3: after the leaching is completed, adjusting pH value of the second ore pulp, and then filtering to obtain a vanadium-containing filtrate and a residue;

[0047] S4: adding water to the residue, and obtaining a third ore pulp after stirring;

[0048] S5: adjusting pH value of the third ore pulp to make the complex precipitated metal gradient decomplexing;

[0049] S6: adding the gradient decomplexing solution to a precipitant, and obtaining a fourth ore pulp after stirring;

[0050] S7: adjusting pH value of the fourth ore pulp to gradient precipitate and recover metal impurities.

[0051] In the method for efficiently and selectively leaching vanadium from vanadium slag clinker according to the present application, vanadium elements can be directionally dissolved in the vanadium slag leaching stage, so that the obtained vanadium-containing leaching solution can directly enter the subsequent vanadium precipitation process, without the need to additionally add a unit for removing impurities, thereby shortening the process, reducing energy consumption and improving the process economy.

[0052] In some specific embodiments, before step S1, the method further comprises: grinding the vanadium slag to a particle size of less than 0.07 mm, with the portion of more than 80 wt% being less than 0.07 mm. The vanadium slag is ground by a ball mill. After grinding, the particle size of the vanadium slag is significantly reduced, and the specific surface area is greatly increased, so that the contact area between the solvent and the vanadium slag is expanded; during leaching, more target components such as vanadate can fully contact and react with the leaching agent, thereby accelerating the transfer of valuable elements such as vanadium to the solution.

[0053] On the basis of the above embodiments, the leaching agent is at least nitrite or diethyldithiocarbamate or a mixture of multiple components; preferably, the leaching agent comprises 0.05 mol / L of sulfuric acid and calcium nitrite, and the mass ratio of diethyldithiocarbamate sodium, calcium nitrite and diethyldithiocarbamate sodium is (1-25):1.

[0054] Sulfuric acid has strong acidity and can provide a large number of hydrogen ions in an aqueous solution; during leaching, sulfuric acid can provide hydrogen ions for calcium nitrite; so that calcium nitrite is converted into nitrous acid.

[0055] Calcium nitrite is a multifunctional chemical substance, which is mainly used as an efficient additive for concrete. Under acidic conditions, it can be converted into nitrous acid, which can oxidize V 3+ into VO2 + with high solubility, which can destroy the lattice stability and is beneficial to the leaching of vanadium.

[0056] Sodium diethyldithiocarbamate is an excellent metal complexing agent, which can instantaneously dissociate CSS- active groups in acid slurry, accurately complex with metal impurities, and generate M(DDTC)n precipitate with dense crystal form and uniform particle size, while VO2+ remains stable in the liquid phase due to the low three orders of magnitude of the complexation constant; only by switching the pH gradient, the impurity metal can be sequentially decomplexed and reprecipitated, so that the impurity metal is recovered step by step, and finally the ultra-high purity vanadium liquid is obtained.

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

[0058] Generally, vanadium extraction from vanadium slag material adopts a three-stage process of "leaching-purification-vanadium precipitation", which can remove impurities by chemical precipitation, solvent extraction or ion exchange, and finally obtain V2O5 by vanadium precipitation; while the present application adopts a one-step selective leaching process for vanadium extraction, in which calcium nitrite becomes the core reagent for breaking through the bottleneck of vanadium leaching rate through the triple synergistic mechanism of "oxidation-complexation-precipitation". First, HNO2 released by acidic decomposition acts as a selective oxidizing agent, which oxidizes V 3+ in the dense Fe2O3-V2O3 solid solution wrapped with vanadium into high-solubility VO2 + , which destroys the lattice stability and exposes the physically encapsulated vanadium to the sulfuric acid medium; secondly, Ca 2+ reacts with SO4 2- to generate CaSO4·2H2O precipitate, which not only eliminates the inhibitory effect of sulfate on vanadium dissolution (avoids the formation of CaSO4 wrapping layer), but also generates microcracks inside the particles through crystallization stress, expanding the penetration channel for sulfuric acid. At the same time, a dense calcium sulfate passivation layer may be formed on the surface of calcium vanadate mineral during acid leaching, which hinders the inward diffusion of H + and the outward diffusion of vanadium. The generation and escape of nitrogen oxide gas can physically disturb and destroy this passivation film, opening up channels for mass transfer of reactants and products, and significantly accelerating the reaction kinetics. Sodium diethyldithiocarbamate instantaneously dissociates CSS- active groups in acid slurry, accurately complexes with metal impurities, and generates M(DDTC)n precipitate with dense crystal form and uniform particle size, while VO2 +It is still stable in liquid phase due to low complexation constant by three orders of magnitude; it can be deligated in turn only by switching pH gradient; the core mechanism of imino-disuccinic acid tetrasodium (IDS-Na4) and methyl glycine diacetic acid trisodium (MGDA-Na3) to precipitate metal ions is "chelation-dispersion-rechelation" cycle: both of them are first coordinated with polycarboxylate and imino to lock metal ions into stable water-soluble chelate ring, preventing them from growing as crystal nucleus; when the local supersaturation degree of the solution increases or the pH / temperature changes, the chelate adsorbed on the surface of the nascent microcrystal is stripped by double electric layer repulsion, forming a negative charge protective shell to prevent the crystal from growing and settling, achieving "precipitation inhibition"; if the concentration of metal ions continues to increase, the free chelating agent can rechelate the released ions, so that the metal always exists in the form of soluble complex throughout the process. The active group of CSS⁻ added with sodium diethyl dithiocarbamate can make the ion gradient precipitate, thereby realizing the gradient precise recovery of metal ions. Therefore, this method is an efficient and economical leaching intensification means. 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 is currently extracted from vanadium-titanium magnetite mainly by converter blowing and slagging method to produce vanadium slag from blast furnace molten iron, that is, using the principle of selective oxidation, high-speed pure oxygen jet is used to stir the vanadium-containing molten iron in the converter, so that the vanadium in the molten iron is oxidized into high-valence stable vanadium oxide to obtain vanadium slag. After roasting, the 3-valence vanadium in the vanadium iron spinel is converted into 5-valence vanadium compound which is acid-soluble and can be efficiently dissolved in sulfuric acid solution medium. After impurity removal, the vanadium-containing leaching solution can be separated by cooling crystallization to obtain vanadium products.

[0062] On the basis of the above embodiments, the addition amount of the leaching agent is 5-15wt%wt% of the vanadium slag material. Preferably, the addition amount of the leaching agent is 10wt% of the vanadium slag material.

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

[0064] In some specific embodiments, the pH value of the second ore slurry solution is preferably adjusted to 1-3, preferably the pH of the second ore 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 was 99.68%, the recovery rate of Cr was 99.1%, the recovery rate of Mn was 96.3%, the recovery rate of Al was 97.6%, the recovery rate of Mg was 92.5%, the recovery rate of Ti was 95.8%, and the recovery rate of Si was 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 is 98.15%, the recovery rate of Cr is 96.9%, the recovery rate of Mn is 96.8%, the recovery rate of Al is 96.8%, the recovery rate of Mg is 92.7%, the recovery rate of Ti is 94.6%, and the recovery rate of Si is 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 was 99.56%, the recovery rate of Cr was 98.9%, the recovery rate of Mn was 95.6%, the recovery rate of Al was 96.9%, the recovery rate of Mg was 92.7%, the recovery rate of Ti was 93.7%, and the recovery rate of Si was 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 was 86.05%, the recovery rate of Cr was 92.6%, the recovery rate of Mn was 93.5%, the recovery rate of Al was 93.8%, the recovery rate of Mg was 91.2%, the recovery rate of Ti was 92.7%, and the recovery rate of Si was 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; 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 and stir well 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; 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 above 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 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 vanadium slag particles, ground to a size less than 0.07 mm, account for 80 wt%.

3. The method for separating, extracting, and recovering valuable components from vanadium slag according to claim 1, characterized in that: 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; 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.

4. The method for separating, extracting, and recovering valuable components from vanadium slag according to claim 1, characterized in that: The reinforcing agent is nitrite, diethyldithiocarbamate or a mixture thereof, wherein the mass ratio of nitrite to diethyldithiocarbamate is (1-25):1; The nitrites include at least calcium nitrite, ammonium nitrite, nitrite, manganese nitrite, and magnesium nitrite; The diethyldithiocarbamate includes at least sodium diethyldithiocarbamate, calcium diethyldithiocarbamate, and ammonium diethyldithiocarbamate.

5. 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.

6. The method for separating, extracting, and recovering valuable components from vanadium slag according to claim 1, characterized in that: 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 at least sodium diethyldithiocarbamate, ammonium diethyldithiocarbamate, and magnesium diethyldithiocarbamate. The iminodisuccinate includes at least iminodisuccinic acid, tetrasodium iminodisuccinate, and dimagnesium iminodisuccinate. The methylglycine salt includes at least potassium methylglycine diacetate and ammonium methylglycine diacetate.

7. 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.

8. The method for separating, extracting, and recovering valuable components from vanadium slag according to claim 1, characterized in that: The residue separated by filtration includes at least anhydrous ethanol, acetone, deionized water, diethyldithiocarbamic acid, and a solution of methylglycine diacetate.

9. The method for separating, extracting, and recovering valuable components from vanadium slag according to claim 8, characterized in that: 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, wherein the mass ratio of each component in the mixed solution is 1:1.

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