Method for extracting vanadium from dolomite negative pressure roasting vanadium slag through acid leaching

Abstract

The invention provides a method for extracting vanadium by negative pressure roasting of dolomite and acid leaching of vanadium slag, and belongs to the technical field of resource recovery, the method comprises the following steps: crushing the vanadium slag, the dolomite and the vanadium slag to a certain particle size, mixing according to a certain proportion, and pelletizing; carrying out negative pressure roasting on the pellets by adopting a closed furnace to obtain roasted clinker and carbon dioxide; leaching and trapping the carbon dioxide through a calcium-containing aqueous solution to prepare light calcium carbonate; the roasted clinker is leached through sulfuric acid, and a vanadium-containing solution and leaching residues are obtained after leaching; extracting the vanadium-containing solution to prepare vanadyl sulfate; and carrying out magnetic separation on the leaching residues to obtain magnetite, and taking residual tailings as a cement raw material. According to negative pressure roasting, the normal pressure calcification roasting temperature is reduced, the cost is greatly saved, meanwhile, an iron component in the vanadium slag is converted into magnetic ferroferric oxide, the utilization rate of iron is increased, in addition, carbon dioxide enrichment is achieved through the closed furnace, a light calcium carbonate product is prepared through trapping and mineralization, and full-quantization high-value utilization of the vanadium slag component is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of resource recovery, in particular to a method for extracting vanadium from dolomite vacuum roasted vanadium slag by acid leaching. Background Art

[0002] The smelting process of vanadium-titanium magnetite generates a large amount of vanadium-containing waste slag. This slag is rich in vanadium, which has not yet been fully extracted and utilized, as well as numerous other valuable metals. Effectively recycling these metal resources would not only reduce resource waste but also create significant economic benefits.

[0003] Patent CN202410222525.3 discloses a method for enhancing vanadium extraction by self-activation roasting and alkali leaching of vanadium slag. The invention uses calcium oxide and magnesium oxide as roasting additives, and utilizes the reaction of calcium, magnesium components and vanadium components to extract vanadium components from vanadium slag. The additives need to be added twice and the additives also need to be treated with impurities twice, which invisibly increases the cost and excess impurity metals, and cannot be collected separately; Patent CN202010379130.6 discloses a method for producing and pretreating high-magnesium vanadium slag based on magnesia roasting. It is clear that by directly generating high-magnesium vanadium slag in the converter and utilizing the waste heat of the vanadium slag to complete partial oxidation of the vanadium slag, favorable conditions are created for the subsequent simplification of the roasting process and reduction of the roasting cost. However, a large amount of coolant is required in the preparation of high-magnesium vanadium slag, which increases the production cost; Patent CN201910354025.4 discloses a method for cleanly extracting vanadium from vanadium slag. This method uses magnesium-containing raw materials as roasting agents to extract vanadium components from vanadium slag, but requires the addition of ammonia water to adjust the pH for magnesium raw material precipitation, which increases the cost, and the roasting temperature reaches 1000°C.

[0004] In summary, existing vanadium slag treatment methods generally expose a series of problems that need to be solved. From a cost perspective, more additives need to be added to ensure the extraction of vanadium slag, which increases production costs. At the same time, there will be magnesium-containing impurities that need to be extracted and processed separately, which complicates the process flow, consumes a lot of energy, and requires high costs for equipment maintenance. In addition, some valuable metals in the vanadium slag are not fully recovered and are eventually abandoned with waste, which undoubtedly causes a huge waste of resources. Therefore, it is urgent to develop a more efficient, environmentally friendly and economical vanadium slag treatment method to solve the problems of high cost, secondary pollution and waste of resources in the prior art, realize the full recycling of valuable metals in the vanadium slag, and achieve a true zero-emission goal. Summary of the Invention

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for acid leaching vanadium from dolomite vacuum roasted vanadium slag, which solves the technical problems of high cost, secondary pollution and waste of resources in the existing vanadium slag treatment methods.

[0006] In order to achieve the above object, the present invention provides a method for extracting vanadium from dolomite vanadium slag by acid leaching under negative pressure, the method comprising:

[0007] S1. Crushing vanadium slag and dolomite to a certain particle size and mixing them in a certain proportion to form pellets;

[0008] S2, roasting the pellets in S1 in a closed furnace under negative pressure to obtain roasted clinker and carbon dioxide;

[0009] S3, leaching the roasted clinker in S2 with a sulfuric acid solution to obtain a vanadium-containing solution and leaching residue;

[0010] S4, extracting the vanadium-containing solution in S3 to obtain a vanadyl sulfate solution and a raffinate, and subjecting the leached residue to magnetic separation to obtain magnetite and tailings;

[0011] S5. Add calcium oxide to the raffinate in S4 to react and precipitate to obtain magnesium hydroxide and a calcium-containing solution.

[0012] In some embodiments, in the aforementioned method for preparing a nickel-manganese solid solution, the calcium-containing solution in S5 is eluted with the carbon dioxide in S2 to obtain calcium carbonate.

[0013] In some embodiments, in the aforementioned method for preparing a nickel-manganese solid solution, the calcium-containing solution is eluted when the volume of carbon dioxide in the closed furnace accounts for 60% to 70% of the closed furnace.

[0014] In some embodiments, in the aforementioned method for preparing a nickel-manganese solid solution, the mass ratio of the vanadium slag in S1 to the calcium element in the dolomite is 0.6 to 3:1.

[0015] In some embodiments, in the aforementioned method for preparing a nickel-manganese solid solution, the particle size diameter of the vanadium slag and dolomite after crushing is 0.1 μm to 300 μm.

[0016] In some embodiments, the aforementioned method for preparing a nickel-manganese solid solution, wherein the vanadium slag includes one or more of converter vanadium slag, dephosphorization slag, desulfurization slag, steel slag, vanadium-containing alloy slag, vanadium-containing petroleum coke, and vanadium-containing shale; the dolomite includes one or more of calcium oxide, calcium hydroxide, carbide slag, and magnesite; and the closed furnace combustion raw materials include one or more of petroleum coke, coke, coking coal, biomass, and carbon monoxide.

[0017] In some embodiments, in the aforementioned method for preparing a nickel-manganese solid solution, the pressure of the negative pressure roasting in S2 is 0.01 atm to 1 atm, the roasting temperature is 400° C. to 800° C., and the roasting time is 30 min to 120 min.

[0018] In some embodiments, the aforementioned method for preparing a nickel-manganese solid solution, wherein the liquid-solid ratio of the sulfuric acid solution to the calcined clinker in S3 is 3 to 10:1, the leaching temperature is 30°C to 150°C, the concentration of the sulfuric acid solution is 30g / L to 120g / L, the leaching time is 60min to 150min, and the stirring speed is 300rpm to 500rpm.

[0019] In some embodiments, in the aforementioned method for preparing a nickel-manganese solid solution, the magnetite in S4 is magnetic ferroferric oxide, and the tailings are used as a building material.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] Dolomite is used as a calcifying agent. During a closed, negative pressure roasting process, it decomposes into calcium oxide, magnesium oxide, and carbon dioxide. The carbon dioxide is enriched in a closed furnace and captured and mineralized to produce a light calcium carbonate product. This avoids carbon dioxide emissions while increasing the added value of carbon dioxide utilization. Furthermore, negative pressure roasting reduces the roasting temperature by 100°C to 300°C, reducing roasting energy consumption and costs. Furthermore, the calcium oxide and magnesium oxide produced by dolomite roasting react with vanadium slag, destroying the existing vanadium and iron ore phases in the vanadium slag to produce vanadium-containing calcium / magnesium salts and iron oxide. Increasing the dolomite addition ratio fully releases the iron and vanadium components in the vanadium slag. During the roasting process, a carbon reducing agent converts the iron oxide component into a magnetic ferroferric oxide component, which is then leached and recovered through magnetic separation, thereby improving the utilization of the iron component in the vanadium slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic flow chart of a method for extracting vanadium from dolomite vanadium slag by acid leaching using vacuum roasting is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Instead, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0024] Example 1

[0025] S1. Crushing vanadium slag and dolomite to a certain particle size and mixing them in a certain proportion to form pellets;

[0026] S2, roasting the pellets in S1 in a closed furnace under negative pressure to obtain roasted clinker and carbon dioxide;

[0027] S3, leaching the roasted clinker in S2 with a sulfuric acid solution to obtain a vanadium-containing solution and leaching residue;

[0028] S4, extracting the vanadium-containing solution in S3 to obtain a vanadyl sulfate solution and a raffinate, and subjecting the leached residue to magnetic separation to obtain magnetite and tailings;

[0029] S5. Add calcium oxide to the raffinate in S4 to react and precipitate to obtain magnesium hydroxide and a calcium-containing solution.

[0030] Among them, dolomite is used as a calcifying agent for reacting with vanadium slag, and various elements in the dolomite can be extracted and utilized. It can be understood that since it is decomposed in a closed environment, carbon dioxide can be collected. The reaction of dolomite in the closed negative pressure roasting process is:

[0031] CaMg(CO3)→CaO(S)+MgO(S)+2CO2

[0032] In addition, calcium oxide and magnesium oxide will react with vanadium slag to release iron in the vanadium slag. By adding a carbon reducing agent, the iron oxide component is converted into a magnetic ferroferric oxide component. After leaching, it is recovered by magnetic separation. The reaction is:

[0033] FeV2O4+O2→Fe2O3+V2O5

[0034] CaO / MgO+V2O5→Ca3V2O5 / Mg3V2O5

[0035] CaO / MgO+V2O5→Ca2V2O7 / Mg2V2O7

[0036] Fe2SiO5+CaO / MgO→Ca2SiO5 / Mg2SiO5+Fe2O3

[0037] Fe2O3+C→Fe3O4+CO2

[0038] At the same time, the carbon dioxide in the closed environment can be reused to react and leach the calcium-containing solution remaining after the magnesium in the calcium-containing solution and the magnesium-containing solution is extracted, and finally a light calcium carbonate product is obtained. At this point, the iron, manganese and calcium elements in the dolomite can be separated and collected separately, reducing the waste rate and improving the recovery rate of a single production preparation.

[0039] Example 2

[0040] S1: crush vanadium slag and dolomite to 0.1 μm, mix them at a calcium ratio of 0.4, and press the mixture into balls to obtain pellets.

[0041] S2: The pellets in S1 are roasted in a closed furnace to obtain roasted clinker and carbon dioxide. The roasting system pressure is 0.5 atm, the roasting temperature is 600° C., and the roasting time is 2 h.

[0042] S3: Leaching the roasted clinker in S2 into a sulfuric acid solution to obtain a vanadyl sulfate solution and a raffinate, wherein the sulfuric acid solution concentration is 100 g / L, the leaching temperature is 60° C., the leaching time is 2 h, the liquid-to-solid ratio is 3:1, and the stirring speed is 200 rpm.

[0043] The roasting temperature of the method is 300°C lower than that of normal pressure calcification roasting, the volume content of the enriched carbon dioxide product is 65%, and the vanadium leaching rate in the vanadium slag is 93%.

[0044] Example 3

[0045] S1: crush vanadium slag and dolomite to 50 μm, mix them at a calcium ratio of 0.6, and press the mixture into balls to obtain pellets.

[0046] S2: The pellets in S1 are roasted in a closed furnace to obtain roasted clinker and carbon dioxide. The roasting system pressure is 0.6 atm, the roasting temperature is 650° C., and the roasting time is 1 h.

[0047] S3: Leaching the roasted clinker in S2 into a sulfuric acid solution to obtain a vanadyl sulfate solution and a raffinate, wherein the sulfuric acid solution concentration is 50 g / L, the leaching temperature is 50° C., the leaching time is 2 h, the liquid-to-solid ratio is 3:1, and the stirring speed is 200 rpm.

[0048] The roasting temperature of the method is 250°C lower than that of normal pressure calcification roasting, the volume content of the enriched carbon dioxide product is 67%, and the vanadium leaching rate in the vanadium slag is 94%.

[0049] Example 4

[0050] S1: crush vanadium slag and dolomite to 150 μm, mix them at a calcium ratio of 0.8, and press the mixture into balls to obtain pellets.

[0051] S2: The pellets in S1 are roasted in a closed furnace to obtain roasted clinker and carbon dioxide. The roasting system pressure is 0.6 atm, the roasting temperature is 700° C., and the roasting time is 2 h.

[0052] S3: Leaching the roasted clinker in S2 into a sulfuric acid solution to obtain a vanadyl sulfate solution and a raffinate, wherein the sulfuric acid solution concentration is 150 g / L, the leaching temperature is 50° C., the leaching time is 1 h, the liquid-to-solid ratio is 5:1, and the stirring speed is 450 rpm.

[0053] The roasting temperature of the method is 300°C lower than that of normal pressure calcification roasting, the volume content of the enriched carbon dioxide product is 70%, and the vanadium leaching rate in the vanadium slag is 95%.

[0054] Example 5

[0055] S1: crush the vanadium slag and dolomite to 100 μm, mix them at a calcium ratio of 1.0, and press the mixture into balls to obtain pellets.

[0056] S2: The pellets in S1 are roasted in a closed furnace to obtain roasted clinker and carbon dioxide. The roasting system pressure is 0.8 atm, the roasting temperature is 800° C., and the roasting time is 0.5 h.

[0057] S3: Leaching the roasted clinker in S2 into a sulfuric acid solution to obtain a vanadyl sulfate solution and a raffinate, wherein the sulfuric acid solution concentration is 150 g / L, the leaching temperature is 60° C., the leaching time is 1 h, the liquid-to-solid ratio is 4:1, and the stirring speed is 600 rpm.

[0058] The roasting temperature of the method is 100°C lower than that of normal pressure calcification roasting, the volume content of the enriched carbon dioxide product is 70%, and the vanadium leaching rate in the vanadium slag is 96%.

[0059] Example 6

[0060] S1: crush the vanadium slag and dolomite to 300 μm, mix them at a calcium ratio of 1.2, and press the mixture into balls to obtain pellets.

[0061] S2: The pellets in S1 are roasted in a closed furnace to obtain roasted clinker and carbon dioxide. The roasting system pressure is 0.5 atm, the roasting temperature is 750° C., and the roasting time is 1.5 h.

[0062] S3: Leaching the roasted clinker in S2 into a sulfuric acid solution to obtain a vanadyl sulfate solution and a raffinate, wherein the concentration of the sulfuric acid solution is 100 g / L, the leaching temperature is 30° C., the leaching time is 3 h, the liquid-to-solid ratio is 5:1, and the stirring speed is 500 rpm.

[0063] The roasting temperature of the method is 150°C lower than that of normal pressure calcification roasting, the volume content of the enriched carbon dioxide product is 69%, and the vanadium leaching rate in the vanadium slag is 91%.

[0064] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations fall within the scope of the claims and their equivalents, the present invention shall also include such modifications and variations.

[0065] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for extracting vanadium from dolomite vanadium slag by acid leaching under negative pressure, characterized in that: The following steps are involved: S1. Crushing vanadium slag and dolomite to a certain particle size and mixing them in a certain proportion to form pellets; S2, roasting the pellets in S1 in a closed furnace under negative pressure to obtain roasted clinker and carbon dioxide; S3, leaching the roasted clinker in S2 with a sulfuric acid solution to obtain a vanadium-containing solution and leached residue; S4, extracting the vanadium-containing solution in S3 to obtain a vanadyl sulfate solution and a raffinate, and magnetically separating the leached residue to obtain magnetite and tailings; S5. Add calcium oxide to the raffinate in S4 to react and precipitate to obtain magnesium hydroxide and a calcium-containing solution.

2. The method for extracting vanadium from dolomite vanadium slag by acid leaching under negative pressure according to claim 1, characterized in that: The calcium-containing solution in S5 is eluted with the carbon dioxide in S2 to obtain calcium carbonate.

3. The method for extracting vanadium from dolomite vanadium slag by acid leaching under negative pressure according to claim 2, characterized in that: When the volume of carbon dioxide in the sealed furnace accounts for 60% to 70% of the volume of the sealed furnace, the calcium-containing solution is eluted.

4. The method for extracting vanadium from dolomite vanadium slag by acid leaching under negative pressure according to claim 1, characterized in that: The mass ratio of the vanadium slag to the calcium element in dolomite in S1 is 0.6 to 3:

1.

5. The method for extracting vanadium from dolomite vanadium slag by acid leaching under negative pressure roasting according to claim 1, characterized in that: The particle size diameter of the crushed vanadium slag and dolomite is 0.1 μm to 300 μm.

6. The method for extracting vanadium from dolomite vanadium slag by acid leaching under negative pressure according to claim 1 is characterized in that: The vanadium slag includes one or more of converter vanadium slag, dephosphorization slag, desulfurization slag, steel slag, vanadium-containing alloy slag, vanadium-containing petroleum coke, and vanadium-containing shale; the dolomite includes one or more of calcium oxide, calcium hydroxide, carbide slag, and magnesite; the closed furnace combustion raw materials include one or more of petroleum coke, coke, coking coal, biomass, and carbon monoxide.

7. The method for extracting vanadium from dolomite vanadium slag by acid leaching under negative pressure roasting according to claim 1, characterized in that: The gas pressure of the negative pressure roasting in S2 is 0.01atm~1atm, the roasting temperature is 400℃~800℃, and the roasting time is 30min~120min.

8. The method for extracting vanadium from dolomite vanadium slag by acid leaching under negative pressure according to claim 1, characterized in that: The liquid-solid ratio of the sulfuric acid solution to the roasted clinker in S3 is 3 to 10:1, the leaching temperature is 30° C. to 150° C., the concentration of the sulfuric acid solution is 30 g / L to 120 g / L, the leaching time is 60 min to 150 min, and the stirring speed is 300 rpm to 500 rpm.

9. The method for extracting vanadium from dolomite vanadium slag by acid leaching under negative pressure according to claim 1, characterized in that: The magnetite in S4 is magnetic ferrosoferric oxide, and the tailings are used as building materials.

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