Method for extracting vanadium from vanadium slag through chlorination

Abstract

The invention relates to the technical field of chemical metallurgy, and discloses a method for extracting vanadium from vanadium slag through chlorination, which comprises the following steps: S1, fully mixing vanadium slag and a solid carbonizer according to a certain proportion, adding water for wetting, and briquetting; s2, performing inert atmosphere carbonization roasting on the material obtained by briquetting in the step S1; s3, cooling the carbonized slag roasted in the step S2, and then crushing and screening; s4, carrying out chlorination reaction on the screened material obtained in S3; and S5, condensing and separating gaseous volatile components generated in the chlorination reaction in the step S4 to obtain a liquid mixture of vanadium tetrachloride and titanium tetrachloride and a solid mixture of manganese chloride and ferric chloride. According to the scheme, the chlorination efficiency of vanadium and titanium can be greatly improved, and comprehensive utilization of multi-metal resources in the vanadium slag is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of chemical metallurgy, and in particular to a method for extracting vanadium from vanadium slag by chlorination. Background Art

[0002] As a key strategic metal resource, vanadium has a wide range of application values ​​in many fields such as steel, aerospace, additive manufacturing and chemical industry. The raw materials for vanadium extraction are diversified, including vanadium-titanium magnetite, vanadium-containing shale and vanadium-containing secondary resources. Among them, more than 85% of the world's vanadium is extracted from vanadium-titanium magnetite as raw material. The vanadium-containing slag (vanadium slag) obtained by reduction enrichment-selective oxidation treatment of vanadium-titanium magnetite has become the main raw material for industrial vanadium extraction.

[0003] Existing vanadium slag vanadium extraction technologies include two major processes: sodium roasting-water leaching vanadium extraction and calcium roasting-acid leaching vanadium extraction. The common feature of these processes is that by roasting with sodium salt or calcium salt as an additive, the vanadium-containing phase in the vanadium slag is decomposed, and the low-valent vanadium is converted into high-valent vanadate, and then the high-valent vanadate in the roasted material is dissolved through a water leaching or acid leaching process to achieve vanadium extraction. However, these processes have significant defects. First, the sodium roasting-water leaching vanadium extraction process will produce a large amount of ammonia nitrogen wastewater during the ammonium salt precipitation process, affecting environmental protection performance; secondly, the calcium roasting-acid leaching vanadium extraction process has a low vanadium yield due to technical limitations and equipment factors. In addition, these processes mainly focus on the extraction and utilization of vanadium resources, while ignoring the further utilization of resources such as iron, manganese, titanium, and silicon in vanadium slag, thereby limiting the comprehensive utilization rate of resources. In order to solve the above technical problems, the industry has developed a variety of new vanadium slag vanadium extraction technologies. Among them, the chlorination process of vanadium extraction technology, as a new type of vanadium extraction technology, has significant advantages such as high extraction efficiency, clean process, and high product purity, and has been rapidly developed in recent years. The main process of chlorination process of vanadium extraction technology includes: vanadium slag pre-oxidation - selective chlorination - chloride separation and purification - preparation of high-purity vanadium pentoxide products, which provides a new way to achieve sustainable utilization of vanadium resources.

[0004] In the prior art, the relevant literature on vanadium extraction technology by chlorination is as follows: Patent CN200910250443.5 discloses a process for separating vanadium by chlorination roasting of vanadium slag, which uses a solid chlorinating agent for chlorination roasting of vanadium slag to achieve efficient conversion and extraction of vanadium.

[0005] Patent CN201711189974.9 discloses a system and method for producing high-purity vanadium pentoxide by clean chlorination of vanadium resources, and proposes a vanadium slag granulation oxidative roasting-fluidized selective carbon chlorination technology, which significantly improves the chlorination selectivity of vanadium.

[0006] The document "Selective extraction of vanadium from pre-oxidized vanadium slag by carbochlorination in fluidized bed reactor, Journal of Cleaner Production, 2019, 237: 117765" reported the influence law and process control principle of vanadium slag pre-oxidation-selective chlorination extraction. The chlorination rates of vanadium, iron and titanium in the slag were 87.47%, 18.79% and 6.15%, respectively.

[0007] The document "A novel process for simultaneous extraction of iron, vanadium, manganese, chromium, and titanium from vanadium slag by molten salt electrolysis" reports a direct step-by-step chlorination co-extraction technology for vanadium slag. The chlorides of vanadium, iron, titanium and manganese are obtained by chlorinating the vanadium slag in molten salt, and then a multi-metal alloy of vanadium, iron and manganese is prepared by electrolysis. Under optimized conditions, the chlorination rates of vanadium, iron, titanium and manganese in the slag are 76.5%, 90.3%, 79.9% and 97.3%, respectively. This method has a short process flow and is conducive to the comprehensive utilization of multi-metal resources in vanadium slag.

[0008] However, in the above-mentioned prior art, vanadium and titanium, as the components with the greatest added value in vanadium slag, have too low chlorination rates.

[0009] Therefore, there is an urgent need to develop a new chlorination technology that can efficiently extract vanadium, iron, titanium, manganese and other metal resources from vanadium slag, with special attention paid to improving the chlorination rate of vanadium and titanium. Summary of the invention

[0010] In view of this, the purpose of the embodiment of the present invention is to provide a method for extracting vanadium from vanadium slag by chlorination. The present invention not only helps to improve the comprehensive utilization rate of metal resources in vanadium slag, but also provides a new way for the preparation of high-end metal materials.

[0011] Based on the above purpose, an embodiment of the present invention provides a method for extracting vanadium by chlorination of vanadium slag, comprising: S1, fully mixing vanadium slag and solid carburizer in a certain proportion, adding water to moisten and briquetting; S2, subjecting the material briquetting obtained in S1 to carbonization roasting in an inert atmosphere; S3, cooling the carbonized slag roasted in S2, and then crushing and screening it; S4, subjecting the sieved material obtained in S3 to a chlorination reaction; S5, condensing and separating the gaseous volatile components produced by the chlorination reaction in S4 to obtain a liquid mixture of vanadium tetrachloride and titanium tetrachloride and a solid mixture of manganese chloride and ferric chloride.

[0012] According to one embodiment of the present invention, in step S1, the particle size of the vanadium slag is below -200 mesh, and the vanadium slag includes, by weight: 5% to 20% vanadium pentoxide, 25% to 50% ferric oxide, 5% to 15% titanium dioxide, 5% to 10% manganese oxide and 10% to 20% silicon dioxide.

[0013] According to one embodiment of the present invention, in step S1, the particle size of the solid carbonizing agent is -200 mesh, the carbon content of the solid carbonizing agent is above 85%, and the solid carbonizing agent includes petroleum coke, activated carbon, and carbon powder.

[0014] According to one embodiment of the present invention, in step S1, the mass ratio of vanadium slag to solid carburizer is 100:(10-50).

[0015] According to one embodiment of the present invention, in step S1, after the vanadium slag and the solid vanadium slag carbonizing agent are evenly mixed, the amount of water added is 2% to 8% of the mass of the solid material, and the briquetting pressure is 10 to 30 MPa.

[0016] According to one embodiment of the present invention, in step S2, the inert gas is argon, nitrogen or helium with a purity of more than 99.99%, the temperature of carbonization roasting is 1000-1600°C, and the time of carbonization roasting is 2-8 hours.

[0017] According to one embodiment of the present invention, in step S3, the particle size of the material after crushing and screening is 50-500 μm.

[0018] According to one embodiment of the present invention, in step S4, the chlorination reaction method includes a fixed bed and a fluidized bed, the chlorination reaction temperature is 200~500°C, the chlorination reaction time is 30~120 min, the gas flow rate of the chlorination reaction is 0.1~0.5m / s, and the gas composition of the chlorination reaction is chlorine with a purity of more than 99.9% and one or more of nitrogen, argon and helium with a purity of more than 99.9%, and the volume proportion of chlorine in the gas of the chlorination reaction is 50%~100%.

[0019] According to one embodiment of the present invention, in step S5, the condensation temperature is -20~0°C. According to one embodiment of the present invention, in step S5, separation includes subjecting the condensed chloride to sedimentation or centrifugal separation.

[0020] The present invention has at least the following beneficial technical effects: The present invention proposes a new method of high-temperature carbonization-low-temperature chlorination of vanadium slag. The vanadium slag is carbonized and roasted at high temperature, so that vanadium, iron, titanium, manganese and other elements in the carbided slag can be converted into compounds that can be chlorinated. Subsequently, through a low-temperature chlorination process, vanadium, iron, titanium, manganese and other elements are separated in the form of chlorides, so that efficient chlorination and co-extraction of vanadium, iron, manganese and titanium in the carbided slag can be achieved. Through the combination of the above-mentioned high-temperature carbonization and low-temperature chlorination, not only the chlorination efficiency of vanadium and titanium can be greatly improved, but also the comprehensive utilization of multi-metal resources in the vanadium slag is promoted, and pollutant emissions are effectively reduced, which has important environmental protection and economic value. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with specific embodiments.

[0022] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention are intended to cover non-exclusive inclusions; the terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish different objects rather than to describe a specific order. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0023] In addition, reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0024] The present invention provides a method for extracting vanadium from vanadium slag by chlorination, comprising the following steps: S1, fully mixing vanadium slag and solid carburizer in a certain proportion, adding water to moisten and briquetting; S2, subjecting the material briquetting obtained in S1 to carbonization roasting in an inert atmosphere; S3, cooling the carbonized slag roasted in S2, and then crushing and screening it; S4, subjecting the sieved material obtained in S3 to a chlorination reaction; S5, condensing and separating the gaseous volatile components produced by the chlorination reaction in S4 to obtain a liquid mixture of vanadium tetrachloride and titanium tetrachloride and a solid mixture of manganese chloride and ferric chloride.

[0025] In some embodiments, the method of the present invention aims to extract metal elements such as vanadium, iron, titanium, and manganese in the form of chlorides, and then obtain vanadium tetrachloride, titanium tetrachloride, and a mixture of ferric chloride and manganese chloride through fine separation and purification steps. Further, the obtained liquid mixture of vanadium tetrachloride and titanium tetrachloride can be efficiently separated by distillation technology, providing raw materials for the preparation of high-end products such as high-purity metallic vanadium and titanium dioxide. Alternatively, these two chlorides can also be directly used in metal thermal reduction or electrolysis processes to produce vanadium-titanium alloys. On the other hand, the solid mixture of ferric chloride and manganese chloride can be converted into iron-manganese oxides after oxidation, and these oxides can be further used to prepare iron-manganese alloys or other materials with special properties.

[0026] The method of the present invention uses high-temperature carbonization to convert vanadium, iron, titanium, manganese and other elements into chlorinable compounds, while low-temperature chlorination can efficiently chlorinate at a relatively low temperature. The design of this process not only improves the resource recovery rate, but also simplifies the process flow and reduces operating costs. In addition, by recovering metal elements during the chlorination process and separating the chlorinated tailings, pollutant emissions can be effectively reduced, and the metal resources in the vanadium slag can be maximized to reduce resource waste. The efficient extraction of vanadium and titanium resources in vanadium slag and the comprehensive utilization of multi-metal resources such as vanadium, titanium, iron and manganese are achieved.

[0027] In some embodiments, in step S1, the particle size of the vanadium slag is below -200 mesh, and the vanadium slag includes, by weight: 5% to 20% vanadium pentoxide, 25% to 50% ferric oxide, 5% to 15% titanium dioxide, 5% to 10% manganese oxide and 10% to 20% silicon dioxide.

[0028] In some embodiments, in step S1, the particle size of the solid carbonizing agent is -200 mesh, the carbon content of the solid carbonizing agent is above 85%, and the solid carbonizing agent includes petroleum coke, activated carbon, and carbon powder.

[0029] In some embodiments, in step S1, the mass ratio of vanadium slag to solid carburizer is 100:(10~50).

[0030] In some embodiments, in step S1, after the vanadium slag and the solid vanadium slag carbonizing agent are evenly mixed, the amount of water added is 2% to 8% of the mass of the solid material, and the briquetting pressure is 10 to 30 MPa. In some embodiments, in step S2, the inert gas is argon, nitrogen or helium with a purity of 99.99% (volume fraction) or more, the carbonization roasting temperature is 1000-1600°C, and the carbonization roasting time is 2-8 hours. Preferably, argon with a purity of 99.99% (volume fraction) or more is used as the inert gas, wherein the purity of 99.99% refers to the proportion of the target gas component contained in the gas volume fraction.

[0031] In some embodiments, in step S3, the particle size of the material after crushing and screening is 50-500 μm.

[0032] In some embodiments, in step S4, the chlorination reaction method includes a fixed bed and a fluidized bed, the chlorination reaction temperature is 200~500°C, the chlorination reaction time is 30~120 min, the gas flow rate of the chlorination reaction is 0.1~0.5 m / s, and the gas composition of the chlorination reaction is chlorine with a purity of 99.9% (volume fraction) or more and nitrogen with a purity of 99.9% (volume fraction) or more, argon and helium. One or more, the volume proportion of chlorine in the gas of the chlorination reaction is 50%~100%. Fluidized bed is preferred as the chlorination reaction method. Chlorine with a purity of 99.9% (volume fraction) or more and nitrogen with a purity of 99.9% (volume fraction) or more are preferably used as a mixed gas for the chlorination reaction, wherein the volume proportion of chlorine in the mixed gas is 50%~100%.

[0033] In some embodiments, in step S5, the condensation temperature is -20~0°C. In some embodiments, in step S5, the separation includes subjecting the condensed chloride to sedimentation or centrifugation.

[0034] In some embodiments, the method can be implemented in the following manner during production: vanadium slag with a particle size of -200 mesh and petroleum coke with a particle size of -200 mesh are fully mixed in a mass ratio of 100:(10~50). Wherein, the carbon content of petroleum coke is more than 85%, and the vanadium slag includes: 5%-20% vanadium pentoxide, 25%-50% ferric oxide, 5%-15% titanium dioxide, 5%-10% manganese oxide, and 10%-20% silicon dioxide by weight. Water is added to the mixed material according to 2%~8% of the mass of the solid material, and the moistened material is pressed into a block under a pressure of 10~30MPa. The pressed material block is placed in a muffle furnace, and carbonized and roasted at a temperature of 1000~1600℃ for 2~8h under the protection of argon gas with a purity of 99.99%. The carbonized and roasted material block is crushed and sieved to obtain particles with a particle size of 50~500μm. The screened particles are placed in a fluidized bed reactor and subjected to a fluidized chlorination reaction in a mixed gas of nitrogen with a purity of more than 99.9% and chlorine with a purity of more than 99.9%, wherein the temperature of the chlorination reaction is 200-500°C, the time of the chlorination reaction is 30-120 min, and the flow rate of the mixed gas of the chlorination reaction is 0.1-0.5 m / s. The volatile components of the chlorination reaction are condensed at a temperature of -20-0°C, and the condensed chlorides are collected. A liquid mixture of vanadium tetrachloride and titanium tetrachloride and a solid mixture of manganese chloride and ferric chloride are obtained by centrifugal separation, and the chlorination tailings are collected to calculate the chlorination rate of each component.

[0035] The present invention proposes a new method of high-temperature carbonization-low-temperature chlorination of vanadium slag. The vanadium slag is carbonized and roasted at high temperature, so that vanadium, iron, titanium, manganese and other elements in the carbided slag can be converted into compounds that can be chlorinated. Subsequently, through a low-temperature chlorination process, vanadium, iron, titanium, manganese and other elements are separated in the form of chlorides, so that efficient chlorination and co-extraction of vanadium, iron, manganese and titanium in the carbided slag can be achieved. Through the combination of the above-mentioned high-temperature carbonization and low-temperature chlorination, not only the chlorination efficiency of vanadium and titanium can be greatly improved, but also the comprehensive utilization of multi-metal resources in the vanadium slag is promoted, and pollutant emissions are effectively reduced, which has important environmental protection and economic value.

[0036] The present invention is further explained below in conjunction with specific embodiments and comparative examples.

[0037] Example 1 Weigh 2000g of vanadium slag with a particle size of -200 mesh. The vanadium slag includes 5.03% vanadium pentoxide, 45.11% ferric oxide, 14.99% titanium dioxide, 9.72% manganese oxide, and 19.81% silicon dioxide by weight. Mix the vanadium slag with 200g petroleum coke with a particle size of -200 mesh and a carbon content of 95%, add 44g of water to the mixture, press it into balls at a pressure of 10MPa, and use argon gas with a purity of 99.99% as a protective atmosphere to carbonize and roast the ball-formed material at a temperature of 1000℃ for 8h. The carbonized and roasted material is crushed and sieved to prepare a material with a particle size of 50~500μm. 800 g of carbonized material with a particle size of 50-500 μm was taken and placed in a fluidized bed reactor for chlorination reaction. The temperature of the chlorination reaction was 200° C. The time of the chlorination reaction was 120 min. The atmosphere of the chlorination reaction was a mixed gas of chlorine with a purity of more than 99.9% and nitrogen with a purity of more than 99.9%, wherein the volume fraction of chlorine was 50% and the total flow rate of the mixed gas was 0.1 m / s. During the chlorination reaction, the chlorinated volatile components were condensed at a temperature of -20° C. The condensed chlorides were collected and centrifuged to obtain 424 g of a liquid mixture of vanadium tetrachloride and titanium tetrachloride, and 680 g of a solid mixture of ferric chloride and manganese chloride. The chlorinated tailings were collected, and the chlorination rates of vanadium, iron, manganese, titanium and silicon were calculated to be 95.22%, 98.10%, 95.78%, 93.35% and 0.53% respectively based on the mass changes of the elements in the slag before and after the chlorination reaction.

[0038] Example 2 Weigh 2000g of vanadium slag with a particle size of -200 mesh. The vanadium slag includes 15.29% vanadium pentoxide, 38.17% ferric oxide, 12.08% titanium dioxide, 6.12% manganese oxide, and 17.46% silicon dioxide by weight. Mix the vanadium slag with 600g petroleum coke with a particle size of -200 mesh and a carbon content of 95%, add 100g of water to the mixture, press it into balls at a pressure of 20MPa, and carbonize and roast the ball-formed material at a temperature of 1300℃ for 4h in a protective atmosphere of argon gas with a purity of 99.99%. The carbonized and roasted material is crushed and sieved to prepare a material with a particle size of 50~500μm. 1000g of carbonized material with a particle size of 50-500μm was taken and placed in a fluidized bed reactor for chlorination reaction. The temperature of the chlorination reaction was 400℃, the time of the chlorination reaction was 60min, and the atmosphere of the chlorination reaction was a mixed gas of chlorine gas with a purity of more than 99.9% and nitrogen gas with a purity of more than 99.9%, wherein the volume fraction of chlorine gas was 80%, and the total flow rate of the mixed gas was 0.2 m / s. During the chlorination reaction, the chlorinated volatile components were condensed at a temperature of -15℃, and the condensed chlorides were collected and centrifuged to obtain 519g of a liquid mixture of vanadium tetrachloride and titanium tetrachloride, and 702g of a solid mixture of iron chloride and manganese chloride. The chlorinated tailings were collected, and the chlorination rates of vanadium, iron, manganese, titanium, and silicon were calculated to be 96.71%, 99.08%, 97.58%, 92.20%, and 1.17%, respectively, based on the mass changes of the elements in the slag before and after the chlorination reaction.

[0039] Example 3 Weigh 2000g of vanadium slag with a particle size of -200 mesh, which includes 19.96% vanadium pentoxide, 32.82% ferric oxide, 11.23% titanium dioxide, 9.95% manganese oxide, and 10.27% silicon dioxide by weight. Mix the vanadium slag with 1000g petroleum coke with a particle size of -200 mesh and a carbon content of 95%, add 240g of water to the mixture, press it into balls at a pressure of 30MPa, and use argon gas with a purity of 99.99% as a protective atmosphere to carbonize and roast the ball-formed material at 1600℃ for 2h. The carbonized and roasted material is crushed and sieved to prepare a material with a particle size of 50-500μm. 1000g of carbonized material with a particle size of 50-500μm was taken and placed in a fluidized bed reactor for chlorination reaction. The temperature of the chlorination reaction was 500℃, the time of the chlorination reaction was 30 min, the atmosphere of the chlorination reaction was chlorine gas with a purity of more than 99.9%, wherein the volume fraction of chlorine gas was 100%, and the chlorine gas flow rate was 0.5 m / s. During the chlorination reaction, the chlorinated volatile components were condensed at a temperature of 0℃, and the condensed chlorides were collected and centrifuged to obtain 486g of a liquid mixture of vanadium tetrachloride and titanium tetrachloride, and 505g of a solid mixture of ferric chloride and manganese chloride. The chlorinated tailings were collected, and the chlorination rates of vanadium, iron, manganese, titanium, and silicon were calculated to be 97.03%, 99.34%, 98.12%, 92.97%, and 1.67%, respectively, based on the mass changes of the elements in the slag before and after the chlorination reaction.

Claims

1. A method for extracting vanadium from vanadium slag by chlorination, characterized in that: include: S1, fully mixing vanadium slag and solid carburizer in a certain proportion, adding water to moisten and briquetting; S2, subjecting the material briquetting obtained in S1 to carbonization roasting in an inert atmosphere; S3, cooling the carbonized slag roasted in S2, and then crushing and screening it; S4, subjecting the sieved material obtained in S3 to a chlorination reaction; S5, condensing and separating the gaseous volatile components produced by the chlorination reaction in S4 to obtain a liquid mixture of vanadium tetrachloride and titanium tetrachloride and a solid mixture of manganese chloride and ferric chloride.

2. The method according to claim 1, characterized in that In step S1, the particle size of the vanadium slag is below -200 mesh, and the vanadium slag includes, by weight, 5% to 20% vanadium pentoxide, 25% to 50% ferric oxide, 5% to 15% titanium dioxide, 5% to 10% manganese oxide, and 10% to 20% silicon dioxide.

3. The method according to claim 1, characterized in that In step S1, the particle size of the solid carbonizing agent is -200 mesh, the carbon content of the solid carbonizing agent is more than 85%, and the solid carbonizing agent includes petroleum coke, activated carbon, and carbon powder.

4. The method according to claim 1, characterized in that: In step S1, the mass ratio of vanadium slag to solid carburizing agent is 100:(10-50).

5. The method according to claim 1, characterized in that In step S1, after the vanadium slag and the solid vanadium slag carbonizing agent are evenly mixed, the amount of water added is 2% to 8% of the mass of the solid material, and the briquetting pressure is 10 to 30 MPa.

6. The method according to claim 1, characterized in that In step S2, the inert gas is argon, nitrogen or helium with a purity of more than 99.99%, the temperature of carbonization roasting is 1000-1600°C, and the time of carbonization roasting is 2-8 hours.

7. The method according to claim 1, characterized in that In step S3, the particle size of the material after crushing and screening is 50-500 μm.

8. The method according to claim 1, characterized in that In step S4, the chlorination reaction method includes fixed bed and fluidized bed, the chlorination reaction temperature is 200~500℃, the chlorination reaction time is 30~120 min, the gas flow rate of the chlorination reaction is 0.1~0.5 m / s, and the gas composition of the chlorination reaction is chlorine with a purity of more than 99.9% and one or more of nitrogen, argon and helium with a purity of more than 99.9%, wherein the volume proportion of chlorine in the gas of the chlorination reaction is 50%~100%.

9. The method according to claim 1, characterized in that: In step S5, the condensation temperature is -20~0°C.

10. The method according to claim 1, characterized in that In step S5, separation includes subjecting the condensed chloride to sedimentation or centrifugal separation.