A method for producing vanadium metal from vanadium-containing fly ash

Abstract

The present invention provides a method for producing vanadium metal from vanadium-containing fly ash. The method comprises: mixing vanadium-containing fly ash with additives, crosslinking agents, dispersants and catalysts to obtain a mixed material; roasting the mixed material; leaching the roasted product with dilute sulfuric acid, and then adding an oxidizing compound to the leaching solution for reaction; adding ammonia to the product after the reaction to obtain a precipitate; melting the precipitate under an oxidizing atmosphere to obtain a molten material; casting the molten material into a cold mold to produce pentavalent vanadium metal. The method improves the vanadium leaching rate in vanadium-containing fly ash by a crosslinking roasting method to produce vanadium metal. The method can effectively realize the reuse of vanadium-containing fly ash and the preparation of vanadium metal, and realize environmentally friendly comprehensive resource utilization.

Description

Technical Field

[0001] The present invention relates to a method for producing vanadium metal from vanadium-containing fly ash. Background Art

[0002] Rare vanadium metal is widely used. In the process of processing and using vanadium-containing materials, vanadium-containing solid waste will inevitably be produced. Most of the vanadium-containing solid wastes produced and stored are mainly silicates, quartz, feldspars, aluminosilicates, spinel phases, iron minerals and other substances. Vanadium-containing solid wastes are of various types and complex components. Elements such as V and Ti are mostly dispersed in various phases, and the different sources lead to large differences in the properties of vanadium-containing solid wastes, making them difficult to treat. At present, the treatment methods of vanadium-containing solid wastes are mainly stockpiling and preparing building materials with low added value, which not only takes up a lot of space and increases management costs, but also causes waste of resources. At the same time, the toxicity of vanadium and other heavy metal components will also bring harm to the environment.

[0003] Vanadium-containing solid waste can be divided into two categories according to its source: one is produced during the processing of vanadium-containing sources in nature (such as vanadium-titanium magnetite, vanadium-containing shale, vanadium-containing crude oil, etc.), mainly vanadium-containing smelting slag, vanadium extraction tailings, vanadium-containing fly ash and vanadium-containing sludge. Some vanadium-containing fuels contain higher vanadium. The fly ash produced by the combustion of these vanadium-containing fuels (such as vanadium-containing crude oil) contains up to 2.5%-40% V2O5. Studies have shown that vanadium in vanadium-containing fly ash mainly exists in the form of VOSO4; the second is produced during the use of vanadium-containing products, such as vanadium-containing waste catalysts. Summary of the invention

[0004] The object of the present invention is to provide a method capable of realizing effective utilization of vanadium-containing fly ash, wherein the method can realize production of vanadium metal by using vanadium-containing fly ash as raw material.

[0005] In order to achieve the above object, the present invention provides a method for producing vanadium metal from vanadium-containing fly ash, wherein the method comprises:

[0006] Step 1): mixing vanadium-containing fly ash with an additive, a cross-linking agent, a dispersant and a catalyst to obtain a mixed material;

[0007] Step 2): roasting the mixture;

[0008] Step 3): the calcined product is leached with dilute sulfuric acid, and then an oxidizing compound is added to the leaching solution for reaction (in this process, part of the low-valent vanadium can be oxidized to pentavalent vanadium);

[0009] Step 4): adding ammonia to the product after the reaction in step 3) to obtain a precipitate (vanadium pentoxide is precipitated in this process);

[0010] Step 5): melting the precipitate in an oxidizing atmosphere (in this process, molten vanadium pentoxide is obtained) to obtain a melt;

[0011] Step 6): Casting the melt into a cold mold to produce pentavalent vanadium metal.

[0012] The above method uses vanadium-containing fly ash as raw material, and improves the vanadium leaching rate in the vanadium-containing fly ash by cross-linking roasting to produce vanadium metal. The method mixes the vanadium-containing fly ash with additives, cross-linking agents, dispersants and catalysts, roasts and then leaches, thereby improving the vanadium leaching rate in the vanadium-containing fly ash (the leaching rate can be as high as 97%); then, it is oxidized, molten at high temperature, and cooled to obtain pentavalent vanadium metal. The method can effectively realize the reuse of vanadium-containing fly ash and the preparation of vanadium metal, and realize environmentally friendly comprehensive resource utilization.

[0013] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, based on the total mass of the vanadium-containing fly ash being 100%, the V2O5 content in the vanadium-containing fly ash is not less than 20%.

[0014] In the above-mentioned method for producing vanadium metal from vanadium-containing fly ash, preferably, the additive includes polycyclic aromatic hydrocarbons, wherein polycyclic aromatic hydrocarbons refer to aromatic hydrocarbons with three or more rings; more preferably, the additive further includes paraffin; more preferably, the polycyclic aromatic hydrocarbons can be added by adding polycyclic aromatic hydrocarbon-rich light mineral oil (such as catalytic cracking light cycle oil) and / or a polycyclic aromatic hydrocarbon mixture, wherein the mass content of polycyclic aromatic hydrocarbons in the polycyclic aromatic hydrocarbon-rich light mineral oil is not less than 50%.

[0015] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, the crosslinking agent comprises one or a combination of two or more of polytriallyl isocyanurate, hydroxyethyl acrylate compounds, methacrylic acid compounds and blocked crosslinking agents.

[0016] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, the dispersant comprises an oil-soluble polyether surfactant.

[0017] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, the catalyst comprises one or a combination of several of iron, nickel, titanium, silicon, and carbides and oxides thereof.

[0018] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, the weight ratio of the components in the mixture is:

[0019] Vanadium-containing fly ash: additive = 20-50:1

[0020] Vanadium-containing fly ash: cross-linking agent = 10-25:1

[0021] Vanadium-containing fly ash: dispersant = 3.5-5.5:1

[0022] Vanadium-containing fly ash: catalyst = 2-5:1;

[0023] In a specific embodiment, the weight ratio of each component in the mixture is:

[0024] Vanadium-containing fly ash: additive = 40:1

[0025] Vanadium-containing fly ash: cross-linking agent = 20:1

[0026] Vanadium-containing fly ash: dispersant = 5:1

[0027] Vanadium-containing fly ash: catalyst = 3:1.

[0028] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, the oxidizing compound is sodium chlorate; in a specific embodiment, a sodium chlorate solution is added to the leaching solution for reaction.

[0029] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, in step 1), the vanadium-containing fly ash mixed with additives, crosslinking agents, dispersants and catalysts is vanadium-containing fly ash that has been screened by particle size; the particle size of the vanadium-containing fly ash that has been screened by particle size is 60-100 mesh.

[0030] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, in step 1), the particle size of the vanadium-containing fly ash mixed with the additive, the crosslinking agent, the dispersant and the catalyst is 60 mesh to 100 mesh.

[0031] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, step 1) comprises:

[0032] The vanadium-containing fly ash is screened to obtain vanadium-containing fly ash with a particle size of 60 meshes to 100 meshes, and additives, crosslinking agents, dispersants and catalysts are sequentially added to the vanadium-containing fly ash with a particle size of 60 meshes to 100 meshes and stirred to obtain a uniformly mixed mixture.

[0033] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, in step 2), the calcination temperature is 600-900°C.

[0034] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, in step 2), the roasting time is 2-3 hours.

[0035] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, in step 2), during the roasting process, the mass content of free oxygen in the roasting atmosphere is controlled to be 15-25% (eg 20%).

[0036] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, the concentration of H2SO4 in the dilute sulfuric acid (based on the total volume of the dilute sulfuric acid) is 2-5 mol / L.

[0037] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, in step 5), the precipitate is dried before melting;

[0038] More preferably, the drying temperature is 300-400°C (eg 320°C).

[0039] In the above method for producing vanadium metal from vanadium-containing fly ash, preferably, in step 5), the melting is carried out in an oxidizing atmosphere at 1000-1500° C. (eg 1100° C.).

[0040] The present invention also provides vanadium metal prepared by the method for producing vanadium metal from vanadium-containing fly ash.

[0041] The technical solution provided by the present invention realizes the production of vanadium metal using vanadium-containing fly ash as raw material. Compared with the prior art, the technical solution provided by the present invention has the following excellent effects:

[0042] 1) The method provided by the present invention mixes vanadium-containing fly ash with additives, crosslinking agents, dispersants and catalysts, then roasts and leaches, thereby improving the leaching rate of vanadium in the vanadium-containing fly ash.

[0043] The vanadium-containing fly ash is pretreated by a cross-linking reaction, which can cause some of the vanadium-containing small molecular fly ash to aggregate and increase the particle size of the fly ash. The low-valent metal vanadium is partially oxidized and cross-linked, thereby improving the recovery rate of the vanadium-containing fly ash. The additive can improve the structure of the metal vanadium, which is beneficial to the roasting of the vanadium-containing fly ash.

[0044] 2) The method provided by the present invention can be calcined at a lower calcination temperature and in a shorter time, thereby reducing production costs.

[0045] Pretreatment by cross-linking reaction improves the connection state of the vanadium-containing metal, which is beneficial to the roasting reaction. The roasting temperature can be reduced to 600°C and the roasting time can be reduced to 2h.

[0046] 3) The filtrate after ammonia precipitation can be recycled after wastewater treatment.

[0047] 4) The method provided by the present invention has low investment, wide working conditions, strong applicability, easy operation, simple process, low cost, and has obvious economic, environmental and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a flow chart of the method for producing vanadium metal from vanadium-containing fly ash provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0050] A specific embodiment of the present invention provides a method for producing vanadium metal from vanadium-containing fly ash, wherein the method comprises:

[0051] Step 1): screening vanadium-containing fly ash having a V2O5 mass content of not less than 20% to obtain vanadium-containing fly ash with a particle size of 60-100 meshes, and sequentially adding additives, a crosslinking agent, a dispersant and a catalyst to the vanadium-containing fly ash with a particle size of 60-100 meshes and stirring to obtain a uniformly mixed mixture;

[0052] Step 2): calcining the mixture at 600-900° C. for 2-3 hours; wherein the mass content of free oxygen in the calcining atmosphere is 15-25%;

[0053] Step 3): the calcined product is leached with dilute sulfuric acid at a concentration of 2-5 mol / L, and then an oxidizing compound is added to the leaching solution for reaction (in this process, part of the low-valent vanadium can be oxidized to pentavalent vanadium);

[0054] Step 4): adding ammonia to the product after the reaction in step 3) to obtain a precipitate (vanadium pentoxide is precipitated in this process);

[0055] Step 5): drying the precipitate at 300-400° C., and then melting it at 1000-1500° C. in an oxidizing atmosphere (in this process, molten vanadium pentoxide is obtained) to obtain a melt;

[0056] Step 6): Casting the melt into a cold mold to produce pentavalent vanadium metal.

[0057] Among them, the weight ratio of each component in the mixture is:

[0058] Vanadium-containing fly ash: additive = 20-50:1

[0059] Vanadium-containing fly ash: cross-linking agent = 10-25:1

[0060] Vanadium-containing fly ash: dispersant = 3.5-5.5:1

[0061] Vanadium-containing fly ash: catalyst = 2-5:1 additive.

[0062] Wherein, the additive includes polycyclic aromatic hydrocarbons, wherein polycyclic aromatic hydrocarbons refer to aromatic hydrocarbons with three or more rings; further, the additive further includes paraffin; further, the polycyclic aromatic hydrocarbons are added by adding polycyclic aromatic hydrocarbon-rich light mineral oil (such as catalytic cracking light cycle oil) and / or a polycyclic aromatic hydrocarbon mixture, wherein the mass content of polycyclic aromatic hydrocarbons in the polycyclic aromatic hydrocarbon-rich light mineral oil is not less than 50%.

[0063] The crosslinking agent includes one or a combination of two or more of polytriallyl isocyanurate, hydroxyethyl acrylate compounds, methacrylic acid compounds and blocked crosslinking agents.

[0064] Wherein, the dispersant includes an oil-soluble polyether surfactant.

[0065] The catalyst includes one or a combination of iron, nickel, titanium, silicon, their carbides and their oxides.

[0066] In the above specific implementation manner, the leaching rate can reach 97%.

[0067] Example 1

[0068] This embodiment provides a method for producing vanadium metal from vanadium-containing fly ash, and the process is as follows: Figure 1 shown.

[0069] The method includes:

[0070] Collecting vanadium-containing fly ash (V2O5 mass content greater than 20%) generated after heavy oil combustion, screening the collected vanadium-containing fly ash to obtain vanadium-containing fly ash with a particle size of 60 mesh to 100 mesh;

[0071] The screened vanadium-containing fly ash is placed in a reactor, and additives, cross-linking agents, dispersants and catalysts are added to the reactor in sequence and stirred to obtain a uniformly mixed mixture; in the mixture, the weight ratio of each component is: vanadium-containing fly ash: additive = 40:1, vanadium-containing fly ash: cross-linking agent = 20:1, vanadium-containing fly ash: dispersant = 5:1, vanadium-containing fly ash: catalyst = 3:1; wherein the additive is polycyclic aromatic hydrocarbons (in this embodiment, polycyclic aromatic hydrocarbons are added by adding catalytic cracking light cycle oil), the cross-linking agent is an ester-type closed cross-linking agent (TMPTMA, grade T003M, a cross-linking agent of a free radical polymerization system is used in this embodiment), the dispersant is an oil-soluble polyether surfactant (SH-200 is used in this embodiment), and the catalyst is a petroleum coke recarburizer;

[0072] The mixture is heated to below 400°C to distill out the residual fuel fraction, and then the temperature is further raised to 800°C and roasted at 800°C for 2 hours (this process can form vanadium-containing minerals); wherein the content of free oxygen in the roasting atmosphere is 20%; wherein the distilled residual fuel fraction is transported to an oil and gas fractionation device for oil and gas condensation, and the condensed oil is collected and stored in a hydrocarbon oil storage tank;

[0073] The calcined product is pickled and leached with 2 mol / L dilute sulfuric acid, sodium chlorate is added to the leachate for reaction (part of the low-valent vanadium can be oxidized to pentavalent vanadium in the process), ammonia is added to the product after the reaction for precipitation (vanadium pentoxide is precipitated in the process), and the precipitate is filtered to obtain a precipitate; wherein the filtrate obtained by filtration is sent to a sewage treatment plant for sewage treatment and then reused;

[0074] The precipitate is dried at a constant temperature of 320°C, and then melted at 1100°C in an oxidizing atmosphere (in this process, molten vanadium pentoxide is obtained) to obtain a melt;

[0075] The melt is cast into a cold mold to produce pentavalent vanadium metal.

[0076] The pentavalent vanadium metal prepared in this embodiment has a purity of 94%-97% and a leaching rate of up to 97%.

Claims

1. A method for producing vanadium metal from vanadium-containing fly ash, wherein: The method includes: Step 1): Mix vanadium-containing fly ash with additives, crosslinking agents, dispersants and catalysts to obtain a mixed material; wherein the additives include polycyclic aromatic hydrocarbons, which refer to aromatic hydrocarbons with three or more rings; the crosslinking agent includes one or a combination of two or more of polytriallyl isocyanurate, hydroxyethyl acrylate compounds, methacrylic acid compounds and blocked crosslinking agents; the dispersant includes an oil-soluble polyether surfactant; the catalyst includes one or a combination of iron, nickel, titanium, silicon and their carbides and their oxides; Step 2): calcining the mixed material; wherein the calcination temperature is 600-900°C; during the calcination process, the free oxygen content in the calcination atmosphere is controlled to be 15-25%; Step 3): The calcined product is leached with dilute sulfuric acid, and then an oxidizing compound is added to the leaching solution for reaction; wherein the oxidizing compound is sodium chlorate; Step 4): adding ammonia to the product after the reaction in step 3) to obtain a precipitate; Step 5): Melting the precipitate in an oxidizing atmosphere to obtain a melt; wherein the melting is carried out in an oxidizing atmosphere at 1000-1500° C.; Step 6): Cast the melt into a cold mold to produce pentavalent vanadium metal.

2. The method according to claim 1, wherein: Taking the total mass of the vanadium-containing fly ash as 100%, the V2O5 content in the vanadium-containing fly ash is not less than 20%.

3. The method according to claim 1, wherein: The additives further include paraffin wax.

4. The method according to any one of claims 1 to 3, wherein: The weight ratio of each component in the mixture is: vanadium-containing fly ash: additive = 20-50:1 Vanadium-containing fly ash: cross-linking agent = 10-25:1 Vanadium-containing fly ash: dispersant = 3.5-5.5:1 Vanadium-containing fly ash: catalyst = 2-5:

1.

5. The method according to claim 1, wherein: In step 1), the particle size of the vanadium-containing fly ash mixed with the additive, the cross-linking agent, the dispersant and the catalyst is 60 meshes to 100 meshes.

6. The method according to claim 1, wherein: In step 2), the calcination time is 2-3 hours.

7. The method according to claim 1, wherein: The concentration of H2SO4 in the dilute sulfuric acid is 2-5 mol / L.

8. The method according to claim 1, wherein: In step 5), the precipitate is dried before melting; wherein the drying temperature is 300-400°C.

9. The method according to claim 1, wherein: In step 5), the melting is carried out in an oxidizing atmosphere at 1100°C.

10. Vanadium metal prepared by the method for producing vanadium metal from vanadium-containing fly ash according to any one of claims 1 to 9.

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