A method for resource utilization of sodium-free vanadium extraction tailings

Abstract

This invention discloses a method for the resource utilization of sodium-free vanadium extraction tailings, belonging to the field of ironmaking. It involves using dried sodium-free vanadium extraction tailings powder, iron ore, and a binder to manufacture ironmaking pellets. The pellets, by mass percentage, consist of: 7-8% sodium-free vanadium extraction tailings, 18-20% concentrate A, 72-74% concentrate B, and 0.5% bentonite. The sodium-free vanadium extraction tailings refer to the tailings generated during the leaching process of vanadium extraction using the sodium-free direct vanadium extraction process from vanadium-titanium magnetite. This invention not only reduces the cost of pelletizing and ironmaking, as well as the cost of vanadium extraction tailings recovery, but also reduces the amount of bentonite used in the pellets, improves the pellet grade, meets the requirements of raw materials for furnace feed, and ultimately achieves comprehensive utilization of secondary resources and cost reduction.

Description

Technical Field

[0001] This invention belongs to the field of secondary resource comprehensive utilization and processing technology, or the field of ironmaking technology, and in particular relates to a method for resource utilization of tailings after sodium-free vanadium extraction from vanadium-titanium magnetite ore. Background Technology

[0002] Vanadium is a key raw material for aerospace, new energy, and special alloy manufacturing, with the vast majority of vanadium resources found primarily in vanadium-titanium magnetite. Vanadium-titanium magnetite is an important strategic mineral resource, rich in vanadium, titanium, iron, and other metallic elements. Currently, most companies use a long-process indirect vanadium extraction process (vanadium-titanium magnetite - blast furnace - converter - sodium vanadium extraction) to extract metallic elements from vanadium-titanium magnetite. This process is typically used for vanadium-titanium magnetite with a vanadium content of <1%. However, a few companies use a short-process direct vanadium extraction process (vanadium-titanium magnetite - sodium vanadium extraction). This process is characterized by a shorter process and higher vanadium recovery rate, making it suitable for processing vanadium-titanium magnetite with a vanadium content >1%. However, this short-process direct vanadium extraction process uses sodium salts as additives during oxidative roasting. During leaching, some insoluble sodium compounds remain in the tailings, affecting the recovery and reuse of the tailings. Existing methods for treating the tailings mostly involve stockpiling. Therefore, some scholars have proposed a sodium-free vanadium extraction process for vanadium-titanium magnetite based on a short-process direct vanadium extraction technology. This process changes the additives and leaching agents used in the vanadium extraction process, eliminating the use of sodium salts as additives and avoiding the problem of sodium residue in the tailings after leaching. Other scholars have proposed enriching and separating the tailings after vanadium extraction through pelletizing and direct reduction, but this recovery process increases engineering investment and has high costs and energy consumption.

[0003] The main raw material for blast furnace ironmaking is iron ore. During ironmaking, the iron ore is ground and mixed with bentonite and other materials to form pellets that enter the blast furnace. After grinding, the iron ore is sorted into different grades to ensure that different qualities of iron ore can be used, thus reducing pig iron costs. Iron ore powder is generally divided into ordinary concentrate and concentrate A and concentrate B, which differ in quality, iron content, and the content of other substances. When manufacturing pellets, ordinary concentrate, concentrate A, concentrate B, and a certain amount of binder are usually added simultaneously. The binder in the pellets is generally bentonite, which plays a role in binding, increasing strength, and controlling moisture during pellet preparation. However, because bentonite itself is mostly composed of... , These components reduce the iron grade in pellets, affect high-temperature metallurgical performance, and increase raw material costs. Statistics show that for every 1.0% reduction in bentonite usage, pellet grade increases by 0.6% and fuel ratio decreases by 1.2%. Therefore, reducing the bentonite ratio in pellets can improve production, quality, and reduce costs. This invention addresses these problems by proposing a technical solution for recovering sodium-free vanadium extraction tailings from vanadium-titanium ore as pellet raw material and reducing the bentonite ratio, thereby reducing costs while achieving tailings recycling. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a method for the resource utilization of sodium-free vanadium extraction tailings. By adding a certain proportion of sodium-free vanadium-titanium magnetite tailings to the pellets, ironmaking pellets commonly used in traditional blast furnace systems can be manufactured. This not only achieves the recovery of vanadium extraction tailings at the lowest cost, but also reduces the amount of bentonite used in the pellets, improves the pellet grade, meets the various requirements of raw materials for furnace feeding, and ultimately achieves comprehensive utilization of secondary resources and cost reduction.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for the resource utilization of sodium-free vanadium extraction tailings involves using dried sodium-free vanadium extraction tailings powder, iron ore, and a binder to manufacture ironmaking pellets.

[0007] A further improvement to the technical solution of the present invention lies in the following process included in the manufacturing of pellets:

[0008] S1. Preparation of sodium-free vanadium extraction tailings fine powder: The sodium-free vanadium extraction tailings are dehydrated to a moisture content of less than 10% by sun-drying to obtain sodium-free vanadium extraction tailings fine powder.

[0009] S2. Mixing: Mix the sodium-free vanadium extraction tailings fine powder with the binder, iron ore concentrate A, and concentrate B in the proportion required for ironmaking pellets.

[0010] S3. Pelletizing: The above mixture is placed on a pelletizing machine, and pellets are formed by adjusting the rotation speed of the pelletizing disc and the amount of water sprayed to obtain green pellets;

[0011] S4. Preparation of finished pellets: After screening out green pellets that meet the required particle size, dry, preheat, calcine, and cool them to obtain finished pellets.

[0012] A further improvement of the technical solution of the present invention is that: the sodium-free vanadium extraction tailings refers to the tailings generated in the leaching process of vanadium extraction using the sodium-free direct vanadium extraction process from vanadium-titanium magnetite.

[0013] A further improvement of the technical solution of the present invention is that: the binder mentioned in S2 is bentonite; the proportions, by mass percentage, are: 7-8% sodium-free vanadium extraction tailings, 18-20% refined powder A, 72-74% refined powder B, and 0.5% bentonite.

[0014] A further improvement to the technical solution of this invention is that the main substance content and particle size in the sodium-free vanadium extraction tailings, concentrate A, concentrate B, and bentonite are shown in the table below:

[0015]

[0016] A further improvement of the technical solution of the present invention is that: in S3, ball making is carried out on a disc ball making machine. During ball making, dripping water is used to make the material form a mother ball while rolling. Then, dry material is evenly sprinkled in and mist water is added. The ball making disc speed and spray water volume are adjusted to make green balls.

[0017] A further improvement of the technical solution of the present invention is that the ball-forming disc rotates at 10-14 rpm and the water spray volume is 0.2-0.6 tph, and the water volume is adjusted in real time according to the ball-forming effect.

[0018] A further improvement to the technical solution of this invention is that, in S4, the particle size of the green pellets with the required particle size is 10-14 mm; the drying, preheating, calcining, and cooling processes are as follows: The drying preheating temperature is 25-950℃, and the time is 20-25 minutes; Heating: 950℃-1200℃, time 15-20min; Calcination: 1200-1240℃, 20-25 minutes; Cooling: After calcination, the temperature is reduced to room temperature to obtain the finished pellets.

[0019] The technological advancements achieved by this invention due to the adoption of the above technical solutions are as follows:

[0020] Sodium-free vanadium extraction tailings refer to the byproducts generated after roasting and leaching of vanadium-titanium ore through a sodium-free direct vanadium extraction process. Since sodium-free vanadium extraction tailings have already undergone grinding during their production process and meet the fine powder particle size requirements for pelletizing, they can be directly fed into pelletizing feed without secondary processing, saving investment in secondary recycling production lines and providing a new approach to the recycling of sodium-free vanadium extraction tailings.

[0021] 2. This invention provides a solution for replacing bentonite with sodium-free vanadium extraction tailings. In this invention, sodium-free vanadium extraction tailings are incorporated into the pelletizing process. Utilizing the advantages of the tailings' particle size and specific surface area, they improve filling and structural densification during pelletizing, resulting in denser particle packing, optimized overall porosity, more uniform capillary distribution, and more uniform capillary force. This enhances overall cohesion and reduces the amount of binder required in traditional pelletizing processes, thus achieving cost reduction.

[0022] 3. This invention provides a technical method for preparing vanadium-free vanadium extraction tailings into pellets. This invention proposes a complete technical route and method for preparing vanadium-free vanadium extraction tailings into pellets. Pellets calcined using this method can meet national standards for pellet composition and strength. Attached Figure Description

[0023] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0024] This invention provides a method for the resource utilization of sodium-free vanadium extraction tailings, such as... Figure 1 The diagram shows the process of manufacturing ironmaking pellets using dried sodium-free vanadium extraction tailings powder, iron ore, and a binder. The pellet manufacturing process of this invention includes the following steps:

[0025] S1. Preparation of sodium-free vanadium extraction tailings fine powder: The sodium-free vanadium extraction tailings are dehydrated by spreading and drying to a moisture content of less than 10% (including 10%) to obtain sodium-free vanadium extraction tailings fine powder; The sodium-free vanadium extraction tailings refer to the tailings generated in the leaching process of vanadium-titanium magnetite direct sodium-free vanadium extraction process.

[0026] S2. Mixing: Thoroughly mix the sodium-free vanadium extraction tailings fine powder with the binder bentonite, iron ore concentrate A, and concentrate B according to the proportions required for ironmaking pelletizing. The binder here can be bentonite. The proportions, by mass percentage, are: sodium-free vanadium extraction tailings 7-8%, concentrate A 18-20%, concentrate B 72-74%, and bentonite 0.5%, with a total content of 100% for all four substances. The main substance content and particle size of the sodium-free vanadium extraction tailings, concentrate A, concentrate B, and bentonite are shown in Table 1 below.

[0027] Table 1. Main substance content and particle size of each raw material

[0028]

[0029] S3. Pelletizing: The above mixture is placed on a pelletizing machine. Pelletizing is carried out by adjusting the rotation speed of the pelletizing disc and the water spray volume to obtain green pellets. In this process, the mixture is pelletized on a disc pelletizing machine. During pelletizing, dripping water is added to make the mixed material form mother pellets while rolling. Then, the dried mixture is evenly sprinkled in and atomized water is added. The rotation speed of the pelletizing disc and the water spray volume are adjusted to obtain green pellets. The rotation speed of the pelletizing disc is controlled at 10-14 rpm; the water spray volume is controlled at 0.2-0.6 tph, and the water volume is adjusted in real time according to the pelletizing effect.

[0030] S4. Preparation of finished pellets: Green pellets meeting the required particle size are screened, dried, preheated, calcined, and cooled to obtain finished pellets. The required particle size of the green pellets is 10-14 mm; the drying, preheating, calcining, and cooling process is as follows: The drying preheating temperature is 25-950℃, and the time is 20-25 minutes; Heating: 950℃-1200℃, time 15-20min; Calcination: 1200-1240℃, 20-25 minutes; Cooling: After calcination, the temperature is reduced to room temperature to obtain the finished pellets.

[0031] Example 1

[0032] This embodiment of a method for the resource utilization of sodium-free vanadium extraction tailings includes the following process during pellet manufacturing:

[0033] S1. Preparation of sodium-free vanadium extraction tailings fine powder: The sodium-free vanadium extraction tailings are dehydrated to a moisture content of 10% by sun-drying to obtain sodium-free vanadium extraction tailings fine powder; The sodium-free vanadium extraction tailings refer to the tailings generated in the leaching process of vanadium-titanium magnetite direct sodium-free vanadium extraction process.

[0034] S2. Mixing: The above-mentioned sodium-free vanadium extraction tailings fine powder is mixed with bentonite, iron ore concentrate A and concentrate B in a mass ratio of 8% sodium-free vanadium extraction tailings, 20% concentrate A, 71.5% concentrate B and 0.5% bentonite, and stirred until homogeneous. The main substance content and particle size of the sodium-free vanadium extraction tailings, concentrate A, concentrate B and bentonite are shown in Table 1.

[0035] S3. Pelletizing: The above mixture is placed on a pelletizing machine, and pellets are formed by adjusting the rotation speed of the pelletizing disc and the water spray volume to obtain green pellets. In this process, the mixture is pelletized on a disc pelletizing machine. During pelletizing, dripping water is added to make the mixed material form mother pellets while rolling. Then, the dry mixture is evenly sprinkled in and atomized water is added. The rotation speed of the pelletizing disc and the water spray volume are adjusted to obtain green pellets. The rotation speed of the pelletizing disc is 10-14 rpm, and the water spray volume is 0.2-0.6 tph.

[0036] S4. Preparation of finished pellets: Green pellets with a particle size of 10-14 mm are screened, dried, preheated, calcined, and cooled. The drying, preheating, calcining, and cooling processes are as follows: The drying preheating temperature is 950℃, and the time is 20 minutes; Heat to 1000℃ and hold for 20 minutes; Calcination: Calcine at 1200-1240℃ for 25 minutes; Cooling: After calcination, the temperature is reduced to room temperature to obtain the finished pellets.

[0037] The chemical composition of the pellets obtained by the above process in this embodiment is shown in Table 2 below.

[0038] Table 2: Content of various substances in the pellets prepared in Example 1

[0039]

[0040] As shown in Table 2, the pellets prepared by the method in this embodiment have good chemical composition, low content of harmful impurities, Ti content of 0.5-0.6%, and high iron grade, which meet the technical requirements of various raw materials for blast furnace ironmaking.

[0041] To verify the quality of the pellets prepared by the method of the present invention, Table 3 below compares the composition and technical indicators of the pellets of Example 1 of the present invention with those of the original pellets that do not use sodium-free vanadium extraction tailings but add ordinary refined powder.

[0042] Table 3 Comparison of technical parameters between the embodiments and comparative examples

[0043]

[0044] As shown in Table 3 above, the embodiment of the present invention uses 8% sodium-free vanadium extraction tailings to replace 7% ordinary concentrate and about 1% bentonite in the original pellets. The resulting pellets meet the national standards in terms of drop strength, compressive strength, drum index, etc., and are basically consistent. The amount of bentonite used in this embodiment is reduced by about 1.5%. Under the same concentrate ratio, the pellet cost can be reduced by about 20 yuan / ton compared with the conventional production cost. This is of great significance for improving economic efficiency, reducing production costs, and promoting the balance between blast furnace protection and intensified smelting in ironmaking.

Claims

1. A method for the resource utilization of sodium-free vanadium extraction tailings, characterized in that: Iron pellets are manufactured using dried sodium-free vanadium extraction tailings powder, iron ore, and binders.

2. The method for resource utilization of sodium-free vanadium extraction tailings according to claim 1, characterized in that... The process of manufacturing pellets includes the following steps: S1. Preparation of sodium-free vanadium extraction tailings fine powder: The sodium-free vanadium extraction tailings are dehydrated to a moisture content of less than 10% by sun-drying to obtain sodium-free vanadium extraction tailings fine powder. S2. Mixing: Mix the sodium-free vanadium extraction tailings fine powder with the binder, iron ore concentrate A, and concentrate B in the proportion required for ironmaking pellets. S3. Pelletizing: The above mixture is placed on a pelletizing machine, and pellets are formed by adjusting the rotation speed of the pelletizing disc and the amount of water sprayed to obtain green pellets; S4. Preparation of finished pellets: After screening out green pellets that meet the required particle size, dry, preheat, calcine, and cool them to obtain finished pellets.

3. A method for resource utilization of sodium-free vanadium extraction tailings according to any one of claims 1 or 2, characterized in that: The sodium-free vanadium extraction tailings refer to the tailings generated during the leaching process of vanadium extraction using the sodium-free direct vanadium extraction process from vanadium-titanium magnetite.

4. The method for resource utilization of sodium-free vanadium extraction tailings according to claim 2, characterized in that: The binder mentioned in S2 is bentonite; the proportions, by mass percentage, are: sodium-free vanadium extraction tailings 7-8%, refined powder A 18-20%, refined powder B 72-74%, and bentonite 0.5%.

5. The method for resource utilization of sodium-free vanadium extraction tailings according to claim 4, characterized in that... The main substances and particle sizes in the sodium-free vanadium extraction tailings, concentrate A, concentrate B, and bentonite are shown in the table below: 。 6. The method for resource utilization of sodium-free vanadium extraction tailings according to claim 2, characterized in that: In S3, pelletizing is carried out on a disc pelletizing machine. During pelletizing, dripping water is used to make the material form mother balls while rolling. Then, dry material is evenly sprinkled in and mist water is added. The rotation speed of the pelletizing disc and the amount of water sprayed are adjusted to produce green pellets.

7. A method for resource utilization of sodium-free vanadium extraction tailings according to any one of claims 2 or 6, characterized in that: The pelleting disc rotates at 10-14 rpm, and the water spray volume is 0.2-0.6 tph. The water volume is adjusted in real time according to the pelleting effect.

8. The method for resource utilization of sodium-free vanadium extraction tailings according to claim 2, characterized in that: In S4, the required particle size of the green pellets is 10-14 mm; the drying, preheating, calcining, and cooling processes are as follows: The drying preheating temperature is 25-950℃, and the time is 20-25 minutes; Heating: 950℃-1200℃, time 15-20min; Calcination: 1200-1240℃, 20-25 minutes; Cooling: After calcination, the temperature is reduced to room temperature to obtain the finished pellets.

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