Method for preparing wear-resistant alloy containing vanadium, chromium and iron by using vanadium extraction tailings

Abstract

The invention discloses a method for preparing a vanadium-containing ferrochrome alloy from vanadium extraction tailings, and belongs to the technical field of recycling of the vanadium extraction tailings. The method for preparing the iron alloy by using the vanadium extraction tailings comprises the following steps: uniformly mixing the crushed and dried vanadium extraction tailings with a carbonaceous reducing agent and additives such as CaO and SiO2, and then carrying out ball milling, reduction smelting and cooling to obtain a reduction product; the reduction product is crushed, screened, ground and polished to obtain vanadium-containing ferrochrome pig iron with high iron content; the obtained pig iron is remelted and cooled to obtain a wear-resistant alloy ingot, and the wear-resistant alloy ingot can be subsequently used for preparing a wear-resistant alloy ball containing vanadium and chromium; according to the method, valuable metals in the vanadium extraction tailings can be recycled, resource waste is avoided, economic benefits are increased for enterprises, the slag can be detoxified, pollution to the environment is reduced, and therefore high-value utilization of the vanadium extraction tailings is achieved.

Description

Technical Field

[0001] This invention belongs to the field of industrial solid waste recycling technology, and particularly to the field of vanadium extraction tailings resource recycling technology. Specifically, it relates to a method for preparing vanadium-chromium ferroalloys using vanadium extraction tailings. Background Technology

[0002] Vanadium-chromium ferroalloys are high-performance wear-resistant materials with iron as the base material, chromium and vanadium as the main additive elements, and molybdenum, carbon, etc. as other elements. Through alloying design, they exhibit significant hardness and wear resistance. In this type of alloy, vanadium and chromium form carbides (such as VC, Cr7C3), achieving a hardness of 2000~2500 HV, and wear resistance more than 3.2 times better than high-chromium cast iron. The solid solution strengthening and grain refinement effect of vanadium further inhibits grain coarsening and improves high-temperature stability. At the same time, the dense oxide film formed by chromium enhances corrosion resistance; while the grain refinement effect of vanadium improves the toughness of the material, making it suitable for impact and wear environments such as mining machinery. This type of alloy has a wide operating temperature range (-200℃ to 550℃), a strength retention rate of >85% at 400℃, and a thermal expansion coefficient that matches well with ceramic materials. Therefore, vanadium-chromium ferroalloys are widely used in applications such as mining machinery, high-speed tools, and heavy equipment. Current vanadium-chromium ferroalloys are mainly prepared through smelting, heat treatment, and welding. These traditional methods require large quantities of expensive metal raw materials, resulting in relatively high costs. If vanadium-chromium ferroalloys could be prepared using industrial waste, it would not only make effective use of the waste but also reduce the production cost of such products to some extent.

[0003] Vanadium extraction tailings, also known as vanadium leaching residue, are mainly the residues left after vanadium slag undergoes sodium roasting and water leaching for vanadium extraction, or calcification roasting and acid leaching for vanadium extraction. Vanadium extraction tailings are composed of hematite (Fe2O3), iron-titanium ore phases, and pyroxene phases, with hematite being the most abundant phase. However, the composition varies due to the combination of pyroxene and titanium ore phases with different roasting reactants. Due to the characteristics of the calcium-based vanadium extraction process, vanadium extraction tailings contain sulfates, resulting in a sulfur content as high as 1.0%–2.5%, and the S content in the chemical composition is several times higher than that of ordinary iron ore. Currently, China's steel industry generates nearly 1 million tons of vanadium extraction tailings annually, and environmental requirements for vanadium extraction processes are increasingly stringent. Currently, most vanadium extraction tailings are landfilled or stockpiled, resulting in low utilization rates. Direct stockpiling not only occupies a large amount of land but also introduces soluble Cr... 3+ V 5+ These substances pose a significant threat to human health, resulting in the toxicity of the tailings and severe environmental pollution. Furthermore, since vanadium extraction tailings contain not only large amounts of iron but also valuable metals such as vanadium and chromium, discarding them would constitute a substantial waste of resources.

[0004] Because vanadium extraction tailings contain up to 80% fourth-period transition element compounds, they possess strong black coloring properties, a wide range of black coloring and sintering temperatures, and excellent physicochemical and ceramic-forming properties. Therefore, a small amount of vanadium extraction tailings is currently used to produce far-infrared coatings and vanadium-titanium black porcelain. Simultaneously, vanadium extraction tailings contain large amounts of SiO2, Al2O3, and CaO, which are the main silica-alumina components required for building materials such as cement, concrete, ceramics, and tiles. Therefore, a small portion of vanadium extraction tailings can also be used as aggregate in road base layers such as cement and concrete.

[0005] Although vanadium extraction tailings have achieved industrial applications in the preparation of vanadium-titanium black porcelain, far-infrared coatings, and road base aggregates, the usage is relatively small and cannot consume the massive quantities of vanadium extraction tailings. Furthermore, the extraction of valuable metal elements such as iron, vanadium, and chromium from vanadium extraction tailings is highly beneficial, not only increasing the value of the tailings but also minimizing the content of harmful elements. From a developmental perspective, if advanced technologies can be used to transform the tailings into products with added value while solidifying them, it can not only achieve the resource utilization and reduction of solid waste but also bring significant economic and social benefits. Therefore, if the above metal elements are extracted and synthesized into chromium-iron alloys through economical and environmentally friendly means, the corrosion and wear resistance advantages of chromium can be fully utilized, achieving the detoxification and full resource utilization of vanadium extraction tailings. This process design will be clean and efficient, compatible with the actual production processes of iron smelting and vanadium extraction, and easy to scale up for production.

[0006] Chinese invention patent publication CN119076959A discloses a method for producing metallic iron powder using vanadium extraction tailings. The method involves uniformly mixing vanadium extraction tailings, a reducing agent, and additives, followed by reduction roasting and cooling to obtain a reduction product. The reduction product undergoes a first-stage grinding and magnetic separation to obtain an intermediate product with a TFe content of 80-85%. This intermediate product then undergoes a second-stage grinding and magnetic separation to obtain metallic iron powder with a TFe content of 90-95%. Chinese invention patent publication CN116200601A discloses a method for preparing vanadium-chromium pig iron using vanadium extraction tailings. The method involves uniformly mixing vanadium extraction tailings, coal powder, quicklime, and fluorite in a mass ratio of 100:17-35:20-27:0-10, and smelting at 1350-1530℃ for 0.3-1 hour. After the reaction is complete, the reaction product is cooled to room temperature to obtain vanadium-chromium pig iron. The two aforementioned technical solutions primarily rely on reduction methods, which fail to achieve reduction melting and separation. The resulting alloys are small in size, often dispersed within the slag phase, and require additional magnetic separation, which yields poor separation results. Furthermore, this type of smelting process often stops at the extraction of valuable metal elements, failing to produce a final product, indicating an incomplete technological orientation. Therefore, there is an urgent need to propose a technical solution that can efficiently reduce the harmful metal elements Cr and V in the slag phase, thereby lowering slag toxicity, and obtain alloy products with good wear resistance, achieving multiple technical benefits that are both environmentally friendly and economically viable. Summary of the Invention

[0007] To address the aforementioned technical problems, the main objective of this invention is to utilize a specifically designed reduction and melting technique in vanadium extraction tailings to efficiently reduce valuable elements such as Fe, Cr, and V in the slag phase into the alloy phase. This reduces harmful metallic elements Cr and V in the slag phase while simultaneously yielding alloy products. Furthermore, since metallic Cr possesses excellent wear resistance, these alloy products are expected to be applicable in the field of wear-resistant materials, thereby achieving multiple technological benefits of "turning waste into treasure." This approach is both environmentally friendly and possesses significant economic value.

[0008] The specific technical solution of the present invention to solve the above-mentioned technical problems is as follows: A method for preparing vanadium-chromium ferroalloys using vanadium extraction tailings includes the following steps: (1) Crush the vanadium extraction tailings and then dry the crushed slag in an oven.

[0009] (2) Add quicklime, silica and reducing agent to the vanadium extraction tailings dried in step (1), and then mix them evenly to obtain a mixture; wherein the amount of quicklime and silica added is such that the alkalinity in the mixture is controlled at 0.85~2.5, the added reducing agent accounts for 7~16 wt.% of the mass of the vanadium extraction tailings, and the amount of quicklime and silica added is such that the mass percentage of TiO2 in the total amount of quicklime, silica and vanadium extraction tailings is 4~8 wt.%; then the mixture is ball-milled.

[0010] (3) The ball milled mixture obtained after ball milling in step (3) is placed into a crucible and then placed into a heating furnace. The furnace is heated and kept at a constant temperature for smelting. The smelting temperature is 1300~1700℃ and the holding time is 0.5~3h. After the holding time is completed, the reaction product is cooled to room temperature with the furnace and then taken out. The reaction product is then treated to remove slag to obtain vanadium-chromium pig iron.

[0011] (4) The vanadium-chromium pig iron obtained in step (3) is placed into a remelting furnace for remelting. The remelting temperature is 1400~1700℃. After holding at this temperature for 0.5~3h, it is cooled to room temperature with the furnace to obtain an alloy ingot.

[0012] (5) Cut, grind and polish the alloy ingot obtained in step (4) to obtain a vanadium-chromium iron wear-resistant alloy product.

[0013] As a preferred option, the vanadium extraction tailings used are expressed in oxide form as the following mass percentages: Fe2O3: 35%~40wt.%, CaO: 10~16wt.%, SiO2: 10~16wt.%, SO3: 15.00~20.06wt.%, TiO2: 8~10wt.%, MnO: 3%~6%, V2O5: 2~3wt.%, Cr2O3: 1~3wt.%, Al2O3: 1~3wt.%, MgO: 1~3wt.%, with the balance being unavoidable impurities.

[0014] Preferably, when the required hardness of the vanadium-chromium ferroalloy is 42.3~45.3 HRC, the amount of quicklime and silica added in step (2) is such that the basicity of the mixture is 1.0~1.3, the added reducing agent accounts for 10~13 wt.% of the mass of the vanadium extraction tailings, and the amount of quicklime and silica added is such that the mass percentage of TiO2 in the total amount of quicklime, silica and vanadium extraction tailings is 7~8 wt.%; when the required hardness of the vanadium-chromium ferroalloy is 31.5~34.5 HRC, the amount of quicklime and silica added in step (2) is such that the basicity of the mixture is 0.9~1.2, and ... amount of added reducing agent accounts for 10~13 wt.% of the mass of the vanadium extraction tailings, and the amount of added reducing agent accounts for 10~13 wt.% of the mass of the vanadium extraction tailings, and the amount of added reducing agent accounts for 10~13 wt.% of the mass of the vanadium extraction tailings, and the amount of added reducing agent accounts for 10~13 wt.% of the mass of the vanadium extraction tailings, and the amount of added reducing agent accounts for 10~13 wt.% of the mass of the vanadium extraction tailings The reducing agent accounts for 7-10 wt.% of the vanadium extraction tailings by mass, and the amount of quicklime and silica added makes TiO2 account for 6-7 wt.% of the total mass of quicklime, silica, and vanadium extraction tailings. When the required hardness of the vanadium-chromium ferroalloy is 20.1-23.1 HRC, the amount of quicklime and silica added in step (2) makes the alkalinity of the mixture 1.4-1.7, the reducing agent accounts for 7-10 wt.% of the vanadium extraction tailings by mass, and the amount of quicklime and silica added makes TiO2 account for 7-8 wt.% of the total mass of quicklime, silica, and vanadium extraction tailings. The hardness value here is not continuous. Depending on the application, some hardness values ​​are not important. The hardness of this invention is measured at multiple points (approximately 10 points), and the hardness value of all selected points needs to be within the above-mentioned calibrated range.

[0015] Preferably, the vanadium extraction tailings are vanadium extraction tailings produced by the calcium roasting method for smelting vanadium-containing steel slag.

[0016] Preferably, the quicklime contains 97.5 to 99.5 wt.% calcium oxide, and the silica contains 97.5 to 99.5 wt.% silicon dioxide.

[0017] Preferably, the reducing agent is activated carbon.

[0018] Preferably, in step (1), the drying temperature is 100~140℃ and the drying time is 12~24h.

[0019] Preferably, in step (1), the carbon ratio is set to 0.98~1.35.

[0020] Preferably, the ball-to-material ratio in step (2) is (1.5~2.5):1, the ball milling time is 3~6h, and the particle size of the ball-milled mixture obtained after ball milling is 0.1~0.3mm.

[0021] Preferably, in step (3), the melting and holding temperature is 1300~1550℃ (or preferably 1480~1580℃), and the holding time is 0.5~1.5h.

[0022] Preferably, in step (4), the remelting temperature is 1500~1550℃, and the temperature is maintained for 0.5~1.5h.

[0023] Preferably, in step (3), the heating furnace is a vertical vacuum tube furnace; and the crucible is a graphite crucible.

[0024] Preferably, in step (3), the smelting is carried out using a protective gas. First, the heating furnace is evacuated, and then a protective gas is continuously introduced into the heating furnace. The protective gas is nitrogen, and the flow rate of the protective gas is 0.5~1.5L / min.

[0025] Preferably, in step (4), the remelting is also carried out using a protective gas. First, the remelting furnace is evacuated, and then a protective gas is continuously introduced into the remelting furnace. The protective gas is nitrogen, and the flow rate of the protective gas is 0.5~1.5L / min.

[0026] A vanadium-chromium-iron wear-resistant alloy prepared using vanadium extraction tailings, wherein the vanadium-chromium-iron wear-resistant alloy is prepared by the method described above, and the chemical composition of the vanadium-chromium-iron wear-resistant alloy, by mass percentage, is Fe: 80~92wt.%, C: 2%~4%, Cr: 0.5~2.5wt.%, V: 0.5~2.5wt.%, and C: 2%~4%, with the balance being unavoidable impurities; and the recovery rate of Fe from the vanadium extraction tailings is 85~95wt.%, the recovery rate of V is 70~90wt.%, and the recovery rate of Cr is 70~90wt.%.

[0027] The technical advantages of this invention are as follows: 1. This invention improves the fluidity of the slag phase at high temperatures during the smelting process by setting a specific reduction melting process, changing the slag basicity to the required basicity during the batching process, and changing the TiO2 content in the overall material by adjusting the total amount of material added. This reduces the generation of foam slag during the reduction process and achieves efficient reduction melting. If the TiO2 content in the mixture is too high, it will be reduced by carbon during the high-temperature reduction reaction in the smelting process, forming low-valence titanium oxides and high-melting-point substances such as TiC, TiN, and solid solutions of Ti(C,N). This will hinder the fluidity of the molten metal, making it difficult to drip, thus preventing the extraction of chromium and vanadium from the slag phase into the alloy, and failing to obtain the ferrochrome wear-resistant alloy required by this invention. If the TiO2 content in the mixture is too low, a large amount of material needs to be added, which cannot meet the requirements for basicity and reducing agent. If the basicity is too high, the slag phase will become viscous, resulting in poor fluidity and easy formation of foamy slag, thus failing to achieve reduction melting. However, if the basicity is too low, it will cause poor slag turning and discharge, thus failing to achieve normal reduction melting. This invention reasonably limits the basicity and TiO2 content by rationally limiting the raw materials, thereby achieving good fluidity of the slag phase at high temperatures through the combination of these two factors, reducing the formation of foamy slag during the reduction process. Combined with specific smelting and remelting temperatures, reduction melting is achieved to efficiently obtain the alloy product.

[0028] 2. This invention, through direct carbothermic reduction of vanadium extraction tailings, combined with the addition of other materials, enables valuable elements such as Fe, Cr, and V in the slag phase to be reduced to the alloy phase at a high rate. The recovery rates of Fe, V, and Cr in the vanadium extraction tailings are over 85 wt.%, over 70 wt.%, and over 70 wt.%, respectively. This not only achieves a high extraction rate of Cr and V, which are harmful metallic elements in the slag phase, thus realizing a "detoxification" effect on the slag phase, but also allows these elements to exist as beneficial elements in the alloy by transferring them to it. Due to the good wear resistance of metallic Cr, the resulting vanadium-chromium ferroalloy product can be applied in the field of wear-resistant materials. The main objective of this invention is not to obtain a wear-resistant alloy with performance superior to existing technologies, but rather to utilize industrial waste to obtain a product that meets the basic performance requirements of a wear-resistant alloy. Therefore, this invention achieves multiple technical effects of "turning waste into treasure," and the technical solution of this invention is both environmentally friendly and has good economic value.

[0029] 3. This invention removes impurities and forms slag by remelting vanadium-chromium pig iron prepared through a specific process at a specific temperature, further improving the uniformity of the microstructure. It also integrates alloy ingots extracted multiple times, resulting in a wear-resistant vanadium-chromium ferroalloy block with specific hardness. This achieves the effect of directly converting hazardous waste vanadium extraction tailings into wear-resistant alloy products. Furthermore, in the preferred technical solution, this invention analyzes the different hardness final alloys for different application scenarios. By specifically controlling the alkalinity, carbon content, and TiO2 content of the final alloys with different required hardness, it achieves refined and efficient processing of the final alloy preparation for different application scenarios. This not only utilizes large amounts of accumulated vanadium extraction tailings and eliminates Cr pollution risks, but also extracts valuable metals from the slag to obtain final wear-resistant alloy products for different application scenarios. Attached Figure Description

[0030] Figure 1 This is a photograph of the pig iron obtained by the method of preparing vanadium-chromium pig iron using vanadium extraction tailings in Example 1 of the present invention.

[0031] Figure 2 This is a photograph of the pig iron obtained by the method of preparing vanadium-chromium pig iron using vanadium extraction tailings in Example 2 of the present invention.

[0032] Figure 3 This is a photograph of the pig iron obtained by the method of preparing vanadium-chromium pig iron using vanadium extraction tailings in Example 3 of the present invention.

[0033] Figure 4 This is a physical image of the wear-resistant alloy obtained by remelting pig iron, cutting, grinding, and polishing it according to Embodiment 1 of the present invention.

[0034] Figure 5 This is a physical image of the wear-resistant alloy obtained after remelting, cutting, grinding, and polishing pig iron according to Embodiment 2 of the present invention.

[0035] Figure 6 This is a physical image of the wear-resistant alloy obtained by remelting pig iron, cutting, grinding, and polishing it according to Embodiment 3 of the present invention.

[0036] Figure 7 This is a graph showing the mass percentage detection of each element in the XRF quantitative analysis of Example 1.

[0037] Figure 8 This is a graph showing the mass percentage detection of each element in the XRF quantitative analysis of Example 2.

[0038] Figure 9 This is a graph showing the mass percentage detection of each element in the XRF quantitative analysis of Example 3.

[0039] Figure 10This is a photograph of the vanadium-chromium ferroalloy obtained after remelting in Example 1.

[0040] Figure 11 The image shows the backscattered electron diffraction pattern of the slag obtained in Comparative Example 1.

[0041] Figure 12 The image shows the backscattered electron diffraction pattern of the slag obtained in Comparative Example 2.

[0042] Figure 13 The image shown is of the actual product obtained in Comparative Example 3. Detailed Implementation

[0043] The process technology solution of the present invention will be further described below with reference to embodiments and accompanying drawings. Unless otherwise specified, each feature is merely one example of a series of equivalent or similar features. These embodiments are merely for the purpose of aiding understanding the present invention and should not be considered as specific limitations thereof.

[0044] The chemical composition of the vanadium extraction tailings used in the following examples is as follows: Fe2O3: 38.14 wt.%, SO3: 17.69 wt.%, CaO: 12.08 wt.%, SiO2: 11.27 wt.%, TiO2: 8.60 wt.%, MnO: 5.07% (calculated as manganese monoxide rather than manganese dioxide), V2O5: 2.10 wt.%, Cr2O3: 1.49 wt.%, Al2O3: 1.49 wt.%, MgO: 1.16 wt.%, with the balance being unavoidable impurities (less than 1%).

[0045] Example 1 This embodiment illustrates a method for preparing a vanadium-chromium ferroalloy wear-resistant alloy using vanadium extraction tailings as raw material, with the following steps: (expressed in oxide form, mass percentages: Fe₂O₃: 38.14 wt.%, SO₃: 17.69 wt.%, CaO: 12.08 wt.%, SiO₂: 11.27 wt.%, TiO₂: 8.60 wt.%, MnO: 5.07%, V₂O₅: 2.10 wt.%, Cr₂O₃: 1.49 wt.%, Al₂O₃: 1.49 wt.%, MgO: 1.16 wt.), and the balance being unavoidable impurities.) (1) Take 80g of vanadium extraction tailings that have been crushed into small particles and dried at 120℃ for 20h, and mix them with quicklime, silica, and activated carbon at an alkalinity of 1.2 (the alkalinity used in the calculation is a quaternary alkalinity: The carbon-to-O ratio is 1.2 (the carbon content is 1.2 times the amount of O required for reduction, ensuring that all oxygen is reduced). The added reducing agent accounts for 11.55 wt.% of the vanadium extraction tailings by mass, and TiO2 accounts for 7 wt.% of the total. The mixture is prepared by mixing quicklime (10.73 g), silica (7.56 g), and activated carbon (9.24 g), resulting in a total mixture of 107.53 g and a total of 98.26 g of quicklime, silica, and vanadium extraction tailings. Since TiO2 accounts for 8.60 wt.% of the tailings, the mass percentage of TiO2 in the mixture is 7 wt.%, and the purity of the quicklime and silica is 99 wt.%. The mixture is then ball-milled for 5 hours at a ball-to-material ratio of 2:1 to obtain a ball-milled mixture with an average particle size of approximately 0.2 mm.

[0046] (2) The ball-milled mixture obtained after ball milling was placed in a graphite crucible, and then placed in a vertical tubular furnace. The furnace was first evacuated, and then a protective gas was continuously introduced into the furnace. The furnace was then heated and held at 1550℃ for 1 hour. After the holding period, the reaction product was cooled to room temperature with the furnace and then removed. After slag removal, vanadium-chromium pig iron ingots were obtained. Figure 1 As shown, pig iron ingots were successfully obtained, which proves that the valuable metal was reduced to the alloy phase.

[0047] (3) The pig iron ingots obtained in step (2) are remelted a second time. The remelting furnace is first evacuated, and then a protective gas is continuously introduced into the furnace. The protective atmosphere used is nitrogen, with a flow rate of 1 L / min. The remelting temperature is 1550℃, and the holding time is 1 h. After cooling to room temperature in the furnace, a vanadium-chromium ferroalloy wear-resistant alloy ingot is obtained. The obtained vanadium-chromium ferroalloy wear-resistant alloy ingot is as follows: Figure 10 As shown, through Figure 10 It can be seen that the upper part of the product obtained after the second remelting is the slag formed after remelting (the lower part is the alloy), which shows that the second remelting achieves the effect of purifying the alloy, thereby making the alloy structure more uniform.

[0048] (4) The alloy ingot obtained in step (3) is cut, ground, and polished to obtain the wear-resistant alloy product. After XRF quantitative analysis, the following results are obtained: Figure 7 The results show that the wear-resistant alloy block has a chemical composition of V: ​​1.548 wt.%, Cr: 1.492 wt.%, Fe: 90.727 wt.% (other element contents are as follows). Figure 7 (As shown). And through Figure 7It can be seen that the 3σ values ​​of the tested samples are all below 0.12, indicating that the fluctuation range of the measurement results is very small and the test results are very stable. The hardness of the obtained wear-resistant alloy block was measured using a Rockwell hardness tester, and its hardness was found to be 45.3 HRC (the hardness at this location is the average of 10 selected points); and the obtained alloy block... Figure 4 As shown, from Figure 4 As can be seen, the obtained wear-resistant alloy has no surface defects such as shrinkage cavities and cracks, and its uniformity is improved after remelting.

[0049] Example 2 This embodiment illustrates a method for preparing vanadium-containing ferrochrome wear-resistant alloys using the same vanadium extraction tailings as raw materials, processed with different parameters as in Example 1. The method includes the following steps: (1) Take 80g of vanadium extraction tailings that have been crushed into small particles and dried at 120℃ for 20h, and mix them with quicklime, silica and activated carbon at an alkalinity of 1.2 and a carbon ratio of 1.0, i.e., the added reducing agent accounts for 9.63wt.% of the mass of the vanadium extraction tailings and the TiO2 accounts for 6wt.% (specifically, 19.65g of quicklime, 15.01g of silica and 7.70g of activated carbon, so the total amount of the mixture is 122.36g, and the total amount of quicklime, silica and vanadium extraction tailings is 114.66g. Since the TiO2 accounts for 8.60wt.% of the tailings, the mass percentage of TiO2 in the mixture is set to 6wt.%, and the purity of quicklime is 99wt.% and the purity of silica is also 99wt.%). Then, ball mill for 5h at a ball-to-material ratio of 2:1 to obtain a ball-milled mixture with an average particle size of about 0.2mm.

[0050] (2) The mixture obtained after ball milling was placed in a graphite crucible, and then placed in a vertical tubular furnace. The furnace was heated and held at that temperature, using the same protective atmosphere as in Example 1 (first evacuating, then filling with protective gas). The holding temperature was 1550℃, and the holding time was 1 hour. After the holding period, the reaction product was cooled to room temperature with the furnace and then removed. After removing the slag, vanadium-chromium pig iron was obtained. Figure 2 As shown, pig iron ingots were successfully obtained, which proves that the valuable metal was reduced to the alloy phase.

[0051] (3) The pig iron obtained in step (2) was remelted under the same protective atmosphere as in Example 1. The remelting temperature was 1550°C and the holding time was 1 hour. The alloy ingot was obtained after cooling to room temperature in the furnace.

[0052] (4) The alloy ingot obtained in step (3) is cut, ground, and polished to obtain the wear-resistant alloy product. After XRF quantitative analysis, the following results are obtained: Figure 8The results show that the wear-resistant alloy block has a chemical composition of V: ​​0.975 wt.%, Cr: 1.148 wt.%, and Fe: 83.515 wt.%, and is determined by... Figure 8 It can be seen that the 3σ values ​​of the tested samples are all below 0.12, indicating that the fluctuation range of the measurement results is very small and the test results are very stable. The hardness of the obtained wear-resistant alloy block was measured using a Rockwell hardness tester, and its hardness was found to be 33.7 HRC (average of 10 points). Furthermore, the obtained alloy block... Figure 5 As shown, from Figure 5 As can be seen, the obtained wear-resistant alloy is basically free of surface defects such as shrinkage cavities and cracks, and its uniformity is improved after remelting.

[0053] Example 3 This embodiment illustrates a method for preparing vanadium-containing ferrochrome wear-resistant alloys using the same vanadium extraction tailings as raw materials, processed with different parameters as in Example 1. The method includes the following steps: (1) Take 80g of vanadium extraction tailings that have been crushed into small particles and dried at 120℃ for 20h, and mix them with quicklime, silica, and activated carbon at an alkalinity of 1.5 and a carbon ratio of 1.2. The added reducing agent accounts for 11.55wt.% of the mass of the vanadium extraction tailings, and TiO2 accounts for 7wt.% (specifically, 12.86g of quicklime, 5.43g of silica, and 9.24g of activated carbon, so the total amount of the mixture is 107.53g, and the total amount of quicklime, silica, and vanadium extraction tailings is 98.29g. Since the TiO2 content in the tailings is 8.60wt.%, the mass percentage of TiO2 in the mixture is set to 7wt.%, and the purity of quicklime is 99wt.% and the purity of silica is also 99wt.%). Then, ball mill the mixture for 5h at a ball-to-material ratio of 2:1 to obtain a ball-milled mixture with an average particle size of about 0.2mm.

[0054] (2) The mixture obtained after ball milling was placed in a graphite crucible, and then placed in a vertical tubular furnace. The furnace was heated and held at 1550℃ for 0.5h. After the holding period, the reaction product was cooled to room temperature with the furnace and then removed. After removing the slag, vanadium-chromium pig iron was obtained. The obtained vanadium-chromium pig iron is as follows: Figure 3 As shown, from Figure 3 As can be seen, pig iron ingots were successfully obtained, which proves that the valuable metal was reduced to the alloy phase.

[0055] (3) The pig iron obtained in step (2) is remelted at a temperature of 1550°C and held for 1 hour. After cooling to room temperature in the furnace, an alloy ingot is obtained.

[0056] (4) The alloy ingot obtained in step (3) is cut, ground, and polished to obtain the wear-resistant alloy product. Figure 9After quantitative analysis, its chemical composition was determined to be V 1.054 wt.%, Cr 0.819 wt.%, Fe 87.702 wt.%, and further analyzed by... Figure 9 It can be seen that the 3σ values ​​of the tested samples are all below 0.12, indicating that the fluctuation range of the measurement results is very small and the test results are very stable. The hardness of the obtained wear-resistant alloy block was measured using a Rockwell hardness tester, and its hardness was found to be 22.7 HRC. Furthermore, the obtained alloy block... Figure 6 As shown, from Figure 6 As can be seen, the obtained wear-resistant alloy is basically free of surface defects such as shrinkage cavities and cracks, and its uniformity is improved after remelting.

[0057] Furthermore, as can be seen from the settings of Examples 1, 2, and 3, achieving the goal of obtaining a wear-resistant alloy through efficient melting does not necessarily mean lower hardness. The settings for alkalinity, carbon content, and titanium dioxide content are set in a unidirectional manner (the product in Example 1 has the highest hardness, and the product in Example 3 has the lowest hardness, decreasing sequentially from Example 1 to Example 3. However, the alkalinity settings for Example 1 are 1.2, for Example 2 are 1.2, and for Example 3 are 1.5, while the carbon content is 1.2 in Example 1, 1.0 in Example 2, and 1.2 in Example 3, and the titanium dioxide content is 7 wt.% in Example 1, 6 wt.% in Example 2, and 7 wt.% in Example 3). This demonstrates that the parameter settings of the present invention do not merely play an independent role, but rather the parameters are combined to achieve a coordinated effect. The overall coordination of alkalinity, carbon content, and titanium dioxide content yields a specific hardness range.

[0058] Comparative Example 1 This comparative example illustrates a comparative test conducted outside the melting and holding temperature of this invention, and includes the following steps: (1) Take 80g of vanadium extraction tailings that have been crushed and dried for 20h, mix them with quicklime, silica and activated carbon in a ratio of 1.5 for alkalinity, 1.2 for carbon ratio and 7wt.% for TiO2, and ball mill for 5h.

[0059] (2) The mixture obtained after ball milling was placed in a graphite crucible and then placed in a vertical tubular furnace. The furnace was heated and kept at a temperature of 1295℃ for 0.5h. After the heat preservation was completed, the reaction product was cooled to room temperature with the furnace and then taken out. After crushing, only slag was obtained and no pig iron was obtained.

[0060] By analyzing the slag in Comparative Example 1, the following results were obtained using EBSD technology: Figure 11 The EBSD detection image shown is obtained through... Figure 11 It can be observed that a large portion of the ferroalloy particles with smaller diameters are dispersed in the slag. Figure 11The white substance is an alloy. This is because the holding temperature during the smelting process is too low, and the molten iron cannot drip smoothly, thus preventing slag-metal separation and the acquisition of vanadium-chromium pig iron. This demonstrates that the smelting temperature setting of this invention, based on the specific amount of additives and the alkalinity and titanium dioxide content, is specific. Using existing smelting temperatures to process the specific raw materials of this invention cannot yield the final product, thus indicating that the settings of various parameters in this invention also have a synergistic effect.

[0061] Comparative Example 2 This comparative example is used to demonstrate a comparative experiment where the proportion of TiO2 in the total amount of quicklime + silica + vanadium extraction tailings is not within the scope of this invention. The experiment includes the following steps: (1) Take 80g of vanadium extraction tailings that have been crushed and dried for 20h, and mix them with quicklime, silica and activated carbon in a ratio of 1.2 for basicity and 1.2 for carbon ratio (the proportion of TiO2 is basically unchanged. Since the basicity of the original slag is 1.037, only 2.07g of quicklime needs to be added to adjust the basicity to 1.2. At this time, the proportion of TiO2 is 8.43wt.%). The proportion of TiO2 in the total amount of quicklime + silica + vanadium extraction tailings is not within the range set by this invention. Ball mill for 5h.

[0062] (2) The mixture obtained after ball milling was placed in a graphite crucible and then placed in a vertical tubular furnace. The furnace was heated and kept at a temperature of 1550℃ for 0.5h. After the heat preservation was completed, the reaction product was cooled to room temperature with the furnace and then taken out. After crushing, only slag was obtained and no pig iron was obtained.

[0063] The slag obtained in Comparative Example 2 was processed and observed using EBSD technology, as shown below. Figure 12 The EBSD detection image shown is obtained through... Figure 12 As can be seen, the white spots are dispersed throughout the slag, indicating that a small portion of larger ferroalloy particles are dispersed within it. This is because the TiO2 content was not controlled in this comparative example. As the high-temperature reduction reaction proceeds, the higher content of TiO2 is preferentially reduced by the carbonaceous reducing agent to form low-valence titanium oxides and high-melting-point TiC, TiN, and solid solutions of Ti(C,N). This alters the physical properties of the slag, making it less fluid and highly viscous, preventing the molten iron from dripping smoothly. Therefore, this setup is unfavorable for the formation of pig iron lumps. In other words, the initial limitation of titanium dioxide content in the total mixture, as set in this invention, is an innovative condition setting for this specific melting process. This condition setting enables efficient melting at this alkalinity.

[0064] Comparative Example 3 This comparative example is used to illustrate a comparative test not conducted under the alkalinity conditions of this invention, and includes the following steps: (1) Take 80g of vanadium extraction tailings that have been crushed and dried for 20h, mix them with quicklime, silica and activated carbon in a ratio of 0.8 basicity, 1.0 carbon ratio and 7wt.% TiO2, and ball mill for 5h.

[0065] (2) The mixture obtained after ball milling was placed in a graphite crucible, and then placed in a vertical tubular furnace. The furnace was heated and held at 1550℃ for 0.5 hours. After the holding period, the reaction product was cooled to room temperature with the furnace and then removed. Upon crushing, only slag was obtained; no pig iron was produced. The obtained product is as follows: Figure 13 As shown.

[0066] like Figure 13 As shown, the reduced pellets have many elliptical and blocky particles embedded in the slag on their surface. This indicates that when the basicity is low, the low-basicity slag may have extremely high viscosity during the melting process, making it impossible to completely melt. Even if some metal is reduced, it cannot effectively settle to the bottom of the furnace to form an alloy due to the high viscosity of the slag phase. Therefore, the reduced metal particles are dispersed in the slag and cannot be separated by simple gravity settling. This proves that by simultaneously limiting the basicity and TiO2 content, the present invention can ensure the production of vanadium-chromium ferroalloy wear-resistant alloy under the specific treatment method of vanadium extraction tailings.

[0067] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing vanadium-chromium ferroalloy wear-resistant alloy using vanadium extraction tailings, characterized in that, Includes the following steps: (1) Crush the vanadium extraction tailings and then dry the crushed tailings in an oven; (2) Add quicklime, silica and reducing agent to the vanadium extraction tailings dried in step (1), and then mix them evenly to obtain a mixture; wherein the amount of quicklime and silica added is such that the alkalinity in the mixture is controlled at 0.85~2.5, the added reducing agent accounts for 7~16 wt.% of the mass of the vanadium extraction tailings, and the amount of quicklime and silica added is such that the mass percentage of TiO2 in the total amount of quicklime, silica and vanadium extraction tailings is 4~8 wt.%; then the mixture is ball-milled; (3) The ball milled mixture obtained after ball milling in step (3) is placed into a crucible and then placed into a heating furnace. The furnace is heated and kept at a constant temperature for melting. The melting temperature is 1300~1700℃ and the holding time is 0.5~3h. After the holding time is completed, the reaction product is cooled to room temperature in the furnace and then taken out. The reaction product is treated to remove slag to obtain vanadium-chromium pig iron. (4) The vanadium-chromium pig iron obtained in step (3) is placed into a remelting furnace for remelting. The remelting temperature is 1400~1700℃. After holding at this temperature for 0.5~3h, it is cooled to room temperature with the furnace to obtain an alloy ingot. (5) Cut, grind and polish the alloy ingot obtained in step (4) to obtain a vanadium-chromium iron wear-resistant alloy product.

2. The method for preparing vanadium-chromium ferroalloy wear-resistant alloy using vanadium extraction tailings according to claim 1, characterized in that, The vanadium extraction tailings used, expressed as oxides, are as follows by mass percentage: Fe₂O₃: 35%~40 wt.%, CaO: 10~16 wt.%, SiO₂: 10~16 wt.%, SO₃: 15.00~20.06 wt.%, TiO₂: 8~10 wt.%, MnO: 3%~6%, V₂O₅: 2~3 wt.%, Cr₂O₃: 1~3 wt.%, Al₂O₃: 1~3 wt.%, MgO: 1~3 wt.%. The balance is unavoidable impurities.

3. The method for preparing vanadium-chromium ferroalloy wear-resistant alloy using vanadium extraction tailings according to claim 1 or 2, characterized in that, When the required hardness of the vanadium-chromium ferroalloy is 42.3~45.3 HRC, the amount of quicklime and silica added in step (2) is such that the basicity of the mixture is 1.0~1.3, the added reducing agent accounts for 10~13 wt.% of the mass of the vanadium extraction tailings, and the amount of quicklime and silica added is such that the mass percentage of TiO2 in the total amount of quicklime, silica and vanadium extraction tailings is 7~8 wt.%; when the required hardness of the vanadium-chromium ferroalloy is 31.5~34.5 HRC, the amount of quicklime and silica added in step (2) is such that the basicity of the mixture is 0.9~1.2, and ... TiO2 added is such that the mass percentage of TiO2 in the total amount of quicklime, silica and vanadium extraction tailings is 7~8 wt.%; The reducing agent accounts for 7-10 wt.% of the vanadium extraction tailings by mass, and the amount of quicklime and silica added makes TiO2 account for 6-7 wt.% of the total amount of quicklime, silica and vanadium extraction tailings by mass. When the required hardness of the vanadium-chromium ferroalloy is 20.1-23.1 HRC, the amount of quicklime and silica added in step (2) makes the alkalinity of the mixture 1.4-1.7, the reducing agent accounts for 7-10 wt.% of the vanadium extraction tailings by mass, and the amount of quicklime and silica added makes TiO2 account for 7-8 wt.% of the total amount of quicklime, silica and vanadium extraction tailings by mass.

4. The method for preparing vanadium-chromium ferroalloy wear-resistant alloy using vanadium extraction tailings according to claim 1, characterized in that, The vanadium extraction tailings are the vanadium extraction tailings produced by the calcium roasting method in the smelting of vanadium-containing steel slag.

5. The method for preparing vanadium-chromium ferroalloy wear-resistant alloy using vanadium extraction tailings according to claim 1 or 2, characterized in that, The quicklime contains 97.5-99.5 wt.% calcium oxide, and the silica contains 97.5-99.5 wt.% silicon dioxide. The reducing agent is activated carbon.

6. The method for preparing vanadium-chromium ferroalloy wear-resistant alloy using vanadium extraction tailings according to claim 1 or 2, characterized in that, In step (1), the drying temperature is 100~140℃ and the drying time is 12~24h; The ball-to-material ratio in step (2) is (1.5~2.5):1, the ball milling time is 3~6h, and the particle size of the ball mill mixture obtained after ball milling is 0.1~0.3mm.

7. The method for preparing vanadium-chromium ferroalloy wear-resistant alloy using vanadium extraction tailings according to claim 1 or 2, characterized in that, In step (3), the melting and holding temperature is 1300~1550℃, and the holding time is 0.5~1.5h; In step (4), the remelting temperature is 1500~1550℃, and the temperature is maintained for 0.5~1.5h.

8. The method for preparing vanadium-chromium ferroalloy wear-resistant alloy using vanadium extraction tailings according to claim 1 or 2, characterized in that, In step (3), the heating furnace is a vertical vacuum tube furnace; the crucible is a graphite crucible.

9. The method for preparing vanadium-chromium ferroalloy wear-resistant alloy using vanadium extraction tailings according to claim 1 or 2, characterized in that, In step (3), the smelting is carried out using a protective gas. First, the heating furnace is evacuated, and then a protective gas is continuously introduced into the heating furnace. The protective gas is nitrogen, and the flow rate of the protective gas is 0.5~1.5L / min.

10. A vanadium-chromium ferroalloy wear-resistant alloy prepared using vanadium extraction tailings, characterized in that, The vanadium-chromium-iron wear-resistant alloy is prepared by the method described in any one of claims 1 to 9. The chemical composition of the vanadium-chromium-iron wear-resistant alloy, by mass percentage, is Fe: 80-90 wt.%, Cr: 0.5-2.5 wt.%, V: 0.5-2.5 wt.%, C: 2%-4%, with the balance being unavoidable impurities. Furthermore, the recovery rate of Fe from the vanadium extraction tailings is 85-95 wt.%, the recovery rate of V is 70-90 wt.%, and the recovery rate of Cr is 70-90 wt.%.

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