A method for recovering and preparing scandium concentrate from vanadium-titanium magnetite high-intensity tailings

Abstract

This invention discloses a method for recovering and preparing scandium concentrate from vanadium-titanium magnetite tailings, comprising the following steps: S1, the strong magnetic tailings are fed into a hydrocyclone to obtain underflow and overflow, and the underflow is ground and classified and then separated by strong magnetic separation; S2, the strong magnetic concentrate is subjected to gravity separation to obtain titanium rough concentrate and gravity separation tailings, and the tailings are combined and then desulfurized and floated to obtain sulfur rough concentrate and desulfurized tailings; S3, the desulfurized tailings are pressure filtered and roasted, and leached with mixed acid solution under pressure, and solid-liquid separation is performed to obtain leachate and leach residue; S4, a precipitant is added to the leachate and stirred, and solid-liquid separation is performed to obtain scandium precipitation product and precipitate mother liquor, and the scandium precipitation product is added to alkaline solution and stirred, and solid-liquid separation is performed to obtain scandium concentrate and aluminum liquid. This invention employs a combined pre-enrichment process of hydrocyclone desliming-strong magnetic separation-gravity separation-desulfurization flotation to enrich scandium in strong magnetic tailings. This significantly reduces the amount of ore processed and the cost of subsequent processes, improves economic efficiency, and simultaneously recovers titanium and sulfur, achieving comprehensive resource recovery and utilization.

Description

Technical Field

[0001] This invention relates to the field of comprehensive recycling technology of vanadium-titanium magnetite, and in particular to a method for recovering and preparing scandium concentrate from strongly magnetic tailings of vanadium-titanium magnetite. Background Technology

[0002] Titanium magnetite is a polymetallic symbiotic complex ore of great strategic value in my country, with proven reserves of approximately 10 billion tons and prospective reserves exceeding 30 billion tons. It is mainly concentrated in the Panzhihua-Xichang region of Sichuan, Chengde of Hebei, and the Xinjiang Uygur Autonomous Region. This mineral is not only an important source of iron, vanadium, and titanium resources, but also contains associated key metals such as chromium, cobalt, nickel, and scandium, making it extremely valuable for comprehensive utilization. Scandium (Sc), a key rare metal element, does not form an independent mineral in vanadium-titanium magnetite, but rather generally substitutes for other elements in an isomorphous manner, dispersed in various carrier minerals. It is mainly enriched in common pyroxene, and secondarily distributed in ilmenite and titanium magnetite. In titanium common pyroxene, Sc... 4+ Fe is replaced by a heterovalent isomorphic method. 2+ With Mg 2+ In ilmenite, Fe is replaced. 2+ Mg 2+ and Ti 4+ Scandium content in vanadium-titanium magnetite is 20-30 g / t, which has certain recovery value. At the same time, with the country's emphasis on comprehensive resource recycling, there is a real need to recover associated scandium from vanadium-titanium magnetite.

[0003] For the recovery and utilization of scandium in vanadium-titanium magnetite, the current mainstream process is a refining process of leaching after pretreatment to obtain scandium products. For example, Chinese patent application number 202410595742.7 discloses a method for separating scandium and recovering iron and titanium from scandium-containing vanadium-titanium magnetite tailings. In this method, vanadium-titanium magnetite tailings are mixed evenly with titanium dioxide waste acid and coke to form pellets. After sintering and high-temperature roasting, the pellets are ball-milled to obtain pretreated material. Then, after a weak magnetic-strong magnetic-gravity separation process, scandium concentrate is obtained. The scandium concentrate is then mixed with titanium dioxide waste acid for leaching to recover scandium, thus simultaneously recovering scandium from vanadium-titanium magnetite tailings and titanium dioxide waste acid. However, the process is lengthy, and all vanadium-titanium magnetite tailings need to undergo two high-temperature treatments, consuming a large amount of energy. In addition, the method uses titanium dioxide waste acid as a leaching agent, which generates a large amount of gypsum.

[0004] Chinese patent application number 202311685886.3 discloses a method for recovering scandium from tailings of ultra-low vanadium-titanium magnetite. The process of roasting with sodium hydroxide, acid leaching, extraction, back-extraction, and refining titanium products is used to recover scandium from vanadium-titanium magnetite. However, the process uses an extraction process to enrich scandium in the leachate, which results in high production and operating costs. At the same time, there is also the problem of difficult disposal of waste gypsum.

[0005] The paper "Study on Scandium Recovery from Scandium-Vanadium-Titanium Magnetite Tailings in Panzhihua-Xichang Region" published by Wang Junjie, Xiao Junhui, et al. used vanadium-titanium magnetite tailings as raw material and compared the alkaline melt roasting-leaching process and the fluoride dissolution-leaching process. The direct fluoride leaching process can achieve a scandium leaching rate of 72.22%, and scandium can be extracted without roasting. However, it obviously has the problem of difficult treatment of fluoride-containing gypsum.

[0006] Currently, the extraction of scandium from vanadium-titanium magnetite tailings generally employs a combined process of additive roasting, leaching, extraction, and scandium refining, but all of these methods have some drawbacks: (1) The process directly pre-treats a large amount of vanadium-titanium magnetite tailings, which will lead to a large amount of energy consumption and a surge in processing costs, resulting in poor overall economic benefits of the process. (2) The process uses sulfuric acid as a leaching agent and adds toxic and harmful additives such as fluoride, which will generate a large amount of waste gypsum that is difficult to handle. Improper disposal can easily cause environmental pollution. (3) Due to the low scandium content in the tailings, the scandium content in the leachate is also very low. Existing technologies use extraction processes to separate scandium, which has low separation efficiency and high processing costs.

[0007] In view of this, improvements should be made to the existing technology. Summary of the Invention

[0008] The main objective of this invention is to provide a method for recovering and preparing scandium concentrate from vanadium-titanium magnetite tailings. The method employs a combined pre-enrichment process of hydrocyclone desliming, strong magnetic separation, gravity separation, and desulfurization flotation to enrich scandium in the strong magnetic tailings. This significantly reduces the amount of ore processed and the cost in subsequent processes, improves economic efficiency, and simultaneously recovers titanium and sulfur, achieving comprehensive resource recovery and utilization.

[0009] According to one aspect of the present invention, a method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings is provided, comprising the following steps: S1. Take vanadium-titanium magnetite tailings and adjust them to a predetermined concentration of slurry. Feed the slurry into a hydrocyclone to obtain underflow and overflow. After grinding and classifying the underflow, separate it with strong magnetic separation to obtain strong magnetic concentrate and strong magnetic tailings. S2. After gravity separation of the strong magnetic concentrate, titanium rough concentrate and gravity tailings are obtained. The strong magnetic tailings and gravity tailings are combined and then subjected to desulfurization flotation to obtain sulfur rough concentrate and desulfurization tailings. S3. After desulfurization tailings are filtered and roasted, the roasted material is mixed with acid solution and leached under pressure at a temperature of 180~220℃. Solid-liquid separation is performed to obtain leachate and leach residue. S4. Take the leachate, add the precipitant and stir to react. Then, separate the solid and liquid to obtain the scandium precipitate product and the mother liquor. Take the scandium precipitate product, add the alkaline solution and stir to react. Then, separate the solid and liquid to obtain scandium concentrate and aluminum liquid.

[0010] According to one embodiment of the present invention, in step S1, the cone angle of the hydrocyclone is 10~12°, the overflow port diameter is 22~24mm, and the slurry concentration is controlled at 5~8%.

[0011] According to one embodiment of the present invention, in step S1, the feed pressure of the hydrocyclone is controlled at 0.1~0.15MPa, and the proportion of -0.005mm particle size material in the underflow is below 0.5%.

[0012] According to one embodiment of the present invention, in step S1, the particle size of the material is controlled to be ≤0.01mm during grinding and classification, and the magnetic field strength of the strong magnetic separation is 0.8~1.2T.

[0013] According to one embodiment of the present invention, in step S2, the gravity separation includes one or more separation operations through a spiral chute and / or a shaking table to obtain titanium rough concentrate and gravity tailings, wherein the TiO2 content in the gravity tailings is ≤2%.

[0014] According to one embodiment of the present invention, in step S3, the roasting temperature of the desulfurized tailings is controlled at 1000~1200℃, the roasting time is controlled at 1~2h, and the roasted material is cooled to below 300℃ within 1min.

[0015] According to one embodiment of the present invention, in step S3, the acid solution includes sulfuric acid or nitric acid, the acid concentration is controlled at 15~20wt%, the leaching temperature is controlled at 180~220℃, the leaching time is controlled at 1~2h, and the scandium content in the obtained leaching solution is 20~25mg / L and the aluminum content is 5~8g / L.

[0016] According to one embodiment of the present invention, in step S4, the precipitant includes at least one of sodium hydroxide, ammonia, magnesium oxide and calcium oxide. The precipitation process controls the reaction temperature to 30~50℃, the precipitation pH to 3.5~4.5, the stirring reaction time to 1~4h, and the scandium adsorption precipitation rate to be above 98.5%.

[0017] According to one embodiment of the present invention, in step S4, the scandium precipitate product is washed multiple times with an alkaline solution of pH=7.5~8.5 until the calcium and magnesium content in the material is reduced to below 0.5% after washing.

[0018] According to one embodiment of the present invention, in step S4, the concentration of the alkali solution is controlled at 15~20wt%, the reaction temperature is 80~100℃, and the leaching time is 2~4h.

[0019] According to an embodiment of the present invention, a method for recovering and preparing scandium concentrate from vanadium-titanium magnetite tailings is adopted, which uses a combined pre-enrichment process of hydrocyclone desliming-strong magnetic separation-gravity separation-desulfurization flotation to enrich scandium in the strong magnetic tailings. This process can significantly reduce the amount of ore processed and the cost of subsequent processes, improve economic efficiency, and simultaneously recover titanium and sulfur elements, thus realizing comprehensive resource recovery and utilization. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some implementation examples of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A process flow diagram of a method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings according to an exemplary embodiment of the present invention is shown. Detailed Implementation

[0022] The following detailed description of the embodiments is intended to exemplify the principles of the present invention, but should not be construed as limiting the scope of the invention. The present invention can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0023] These embodiments are provided to make this disclosure thorough and complete, and to fully express the scope of the invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0024] It should be noted that, in the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0025] It should also be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention depending on the specific circumstances. When a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device.

[0026] All terms used in this invention have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0027] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0028] like Figure 1 As shown, the present invention provides a method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings, which includes the following steps: S1. Take vanadium-titanium magnetite tailings and adjust them to a predetermined concentration of slurry. Feed the slurry into a hydrocyclone to obtain underflow and overflow. After grinding and classifying the underflow, separate it with strong magnetic separation to obtain strong magnetic concentrate and strong magnetic tailings. S2. After gravity separation of the strong magnetic concentrate, titanium rough concentrate and gravity tailings are obtained. The strong magnetic tailings and gravity tailings are combined and then subjected to desulfurization flotation to obtain sulfur rough concentrate and desulfurization tailings. S3. After desulfurization tailings are filtered and roasted, the roasted material is mixed with acid solution and leached under pressure at a temperature of 180~220℃. Solid-liquid separation is performed to obtain leachate and leach residue. S4. Take the leachate, add the precipitant and stir to react. Then, separate the solid and liquid to obtain the scandium precipitate product and the mother liquor. Take the scandium precipitate product, add the alkaline solution and stir to react. Then, separate the solid and liquid to obtain scandium concentrate and aluminum liquid.

[0029] In the method for recovering and preparing scandium concentrate from vanadium-titanium magnetite tailings according to an embodiment of the present invention, a combined pre-enrichment process of hydrocyclone desliming-strong magnetic separation-gravity separation-desulfurization flotation is adopted to enrich scandium in the strong magnetic tailings. This can significantly reduce the amount of ore processed and the cost of subsequent processes, improve economic efficiency, and simultaneously recover titanium and sulfur elements, thus realizing comprehensive resource recovery and utilization.

[0030] In step S3, acid leaching mainly involves leaching out scandium and aluminum elements, along with the leaching out of calcium and magnesium ions.

[0031] In step S4, a precipitant is added to precipitate aluminum ions as hydroxides, while scandium is adsorbed into the precipitate, thus separating scandium and aluminum from the solution. Then, an alkaline solution is added to dissolve aluminum as sodium aluminate, while scandium exists in the solid as scandium hydroxide, thus separating scandium and aluminum and obtaining scandium concentrate.

[0032] In some specific embodiments, in step S1, the cone angle of the hydrocyclone is 10~12°, the overflow port diameter is 22~24mm, and the slurry concentration is controlled at 5~8%.

[0033] Based on the above embodiments, in step S1, the feed pressure of the hydrocyclone is controlled at 0.1~0.15MPa, and the proportion of -0.005mm particle size material in the underflow is below 0.5%.

[0034] In some specific embodiments, in step S1, the grinding and classification control the material particle size to ≤0.01mm, and the magnetic field strength of the strong magnetic separation is 0.8~1.2T.

[0035] Based on the above embodiments, in step S2, gravity separation includes one or more separation operations through spiral chute and / or shaking table to obtain titanium rough concentrate and gravity tailings, wherein the TiO2 content in the gravity tailings is ≤2%.

[0036] In some specific embodiments, in step S3, the roasting temperature of the desulfurized tailings is controlled at 1000~1200℃, the roasting time is controlled at 1~2h, and the roasted material is cooled to below 300℃ within 1min.

[0037] Based on the above embodiments, in step S3, the acid solution includes sulfuric acid or nitric acid, the acid concentration is controlled at 15~20wt%, the leaching temperature is controlled at 180~220℃, the leaching time is controlled at 1~2h, and the scandium content in the obtained leaching solution is 20~25mg / L and the aluminum content is 5~8g / L.

[0038] In some specific embodiments, in step S4, the precipitant includes at least one of sodium hydroxide, ammonia, magnesium oxide and calcium oxide. The precipitation process controls the reaction temperature to 30~50℃, the precipitation pH to 3.5~4.5, the stirring reaction time to 1~4h, and the scandium adsorption precipitation rate to be above 98.5%.

[0039] Based on the above embodiments, in step S4, the scandium precipitate product is washed multiple times with an alkaline solution of pH 7.5-8.5 until the calcium and magnesium content in the material is reduced to below 0.5%. The purpose of adding alkaline solution for washing is to wash out the adsorbed calcium and magnesium salts from the precipitate product, reduce the content of impurity elements in the precipitate product, improve the purity of the product, and thus improve the purity of the subsequent scandium concentrate.

[0040] Based on the above embodiments, in step S4, the alkaline solution includes a sodium hydroxide solution.

[0041] Based on the above embodiments, in step S4, the concentration of the alkali solution is controlled at 15~20wt%, the reaction temperature is 80~100℃, and the leaching time is 2~4h.

[0042] The present application will be further described below through specific embodiments.

[0043] Example 1 Strong magnetic tailings from a beneficiation plant in the Panzhihua area were used as the experimental raw material, and the contents of its main elements are shown in Table 1.

[0044] Table 1. Content of major elements in vanadium-titanium magnetite tailings

[0045] The unit is g / t S1. Take vanadium-titanium magnetite tailings and adjust the slurry concentration to 6%. Then feed it into a CZ-150 hydrocyclone at a feed pressure of 0.15MPa for classification. The hydrocyclone cone angle is 11° and the overflow pipe diameter is 22mm. The hydrocyclone underflow and overflow are obtained. The underflow contains 0.4% -0.005mm material and the overflow contains 5.1% +0.01mm material. The underflow is ball-milled for classification. The average particle size of the obtained material is 0.008mm and the maximum particle size is 0.012mm. Then feed the ball-milled material into a vertical ring pulsating strong magnetic separator for separation. The magnetic field strength is 1.0T. Strong magnetic concentrate and tailings are obtained. The strong magnetic concentrate contains 8.56% TiO2 and 18.4g / t Sc. The strong magnetic tailings contain 2.10% TiO2 and 39.7g / t Sc.

[0046] S2. The strong magnetic concentrate obtained in step S1 is adjusted to a pulp concentration of 25% and fed into a spiral sluice for separation, yielding a gravity concentrate and tailings. The gravity concentrate contains 13.56% TiO2 and 11.4 g / t of Sc; the gravity tailings contain 1.80% TiO2 and 41.4 g / t of Sc. The strong magnetic tailings and gravity tailings are combined and fed into a flotation cell for desulfurization flotation. Sulfuric acid is added to adjust the pulp pH to 3.5, then diesel oil and No. 2 oil are added sequentially, stirred for 5 minutes, and then aerated for skimming flotation, yielding an S content of 6.1% and S...C The sample consisted of sulfur concentrate with a selenium content of 3.2 g / t and desulfurization tailings with a selenium content of 0.05% and a saturation content of 40.5 g / t. Compared to strongly magnetic tailings, the scandium recovery rate in the desulfurization tailings was 77.2%.

[0047] S3. The desulfurized tailings from step S2 are filtered to a moisture content of 8.2% and fed into a rotary kiln for roasting. The roasting temperature is controlled at 1100℃ and the roasting time is 2 hours. After roasting, the material is immediately poured into water. The material temperature drops to 120℃ in 0.5 minutes. Then, the cooled material is separated into solid and liquid components. A 20% concentration nitric acid solution is added to the mixture at a liquid-to-solid mass ratio of 2:1. The leaching reaction is carried out at 180℃ for 2 hours. After the reaction, the solid and liquid components are separated to obtain a leachate with a Sc content of 21.2 mg / L and an Al content of 6.5 g / L. The scandium leaching rate is 96.5%.

[0048] S4. Take the leachate from step S3, add 10% magnesium oxide slurry in a water bath at 40℃, adjust the pH of the reaction system to 4.0, and then stir the reaction for 2 hours. Finally, separate the solid and liquid to obtain aluminum scandium precipitate and mother liquor. The scandium content in the mother liquor is 0.4 mg / L, and the scandium precipitation rate is 98.7%. Take the aluminum scandium precipitate and wash it with a solution at pH=8. After washing, the calcium and magnesium content in the precipitate is 0.3%. Then, add 20% sodium hydroxide solution at a liquid-to-solid mass ratio of 2.5:1, control the reaction temperature at 90℃ and react for 3 hours. Finally, separate the solid and liquid to obtain scandium concentrate with a Sc content of 49.8% and aluminum liquid. The scandium recovery rate is 99.4%.

[0049] The above steps yield scandium concentrate with a total recovery rate of 73.1% and a scandium content of 49.8%, achieving comprehensive recovery and utilization of titanium, sulfur, and aluminum elements.

[0050] Example 2 Strong magnetic tailings from a beneficiation plant in the Panzhihua area were used as the experimental raw material, and the contents of its main elements are shown in Table 1.

[0051] S1. Take vanadium-titanium magnetite tailings and adjust the slurry concentration to 6%. Then feed it into a CZ-150 hydrocyclone at a feed pressure of 0.15MPa for classification. The hydrocyclone cone angle is 11° and the overflow pipe diameter is 22mm. The hydrocyclone underflow and overflow are obtained. The underflow contains 0.4% -0.005mm material and the overflow contains 5.1% +0.01mm material. The underflow is ball-milled for classification. The average particle size of the obtained material is 0.008mm and the maximum particle size is 0.012mm. Then feed the ball-milled material into a vertical ring pulsating strong magnetic separator for separation. The magnetic field strength is 1.0T. Strong magnetic concentrate and tailings are obtained. The strong magnetic concentrate contains 8.56% TiO2 and 18.4g / t Sc. The strong magnetic tailings contain 2.10% TiO2 and 39.7g / t Sc.

[0052] S2. The strong magnetic concentrate obtained in step S2 is adjusted to a pulp concentration of 25% and fed into a shaking table for separation, yielding a gravity concentrate and tailings. The gravity concentrate contains 14.21% TiO2 and 10.43 g / t of Sc; the gravity tailings contain 1.62% TiO2 and 42.1 g / t of Sc. The strong magnetic tailings and gravity tailings are combined and fed into a flotation cell for desulfurization flotation. Sulfuric acid is added to adjust the pulp pH to 3.5, then diesel oil and No. 2 oil are added sequentially, stirred for 5 minutes, and then aerated for skimming flotation, yielding an S content of 6.3% and S... C The sample consisted of sulfur concentrate with a sulfur content of 3.6 g / t and desulfurization tailings with a sulfur content of 0.06% and a sc content of 40.9 g / t. Compared to strongly magnetic tailings, the scandium recovery rate in the desulfurization tailings was 78.1%.

[0053] S3. The desulfurized tailings from step S2 are filtered to a moisture content of 8.3% and fed into a rotary kiln for roasting. The roasting temperature is controlled at 1200℃ and the roasting time is 2 hours. After roasting, the material is immediately poured into water. The material temperature drops to 120℃ in 0.5 minutes. Then, the cooled material is separated into solid and liquid components. A 20% nitric acid solution is added to the solid-liquid mixture at a liquid-solid mass ratio of 2:1. The leaching reaction is carried out at 180℃ for 2 hours. After the reaction, the solid and liquid components are separated to obtain a leachate with a Sc content of 21.3 mg / L and an Al content of 6.9 g / L. The scandium leaching rate is 96.9%.

[0054] S4. Take the leachate from step S3, add 10% magnesium oxide slurry in a water bath at 40℃, adjust the pH of the reaction system to 4.0, and then stir the reaction for 2 hours. Finally, separate the solid and liquid to obtain aluminum scandium precipitate and mother liquor. The scandium content in the mother liquor is 0.4 mg / L, and the scandium precipitation rate is 98.8%. Take the aluminum scandium precipitate and wash it with a solution at pH=8. After washing, the calcium and magnesium content in the precipitate is 0.28%. Then, add 20% sodium hydroxide solution at a liquid-to-solid mass ratio of 2.5:1, control the reaction temperature at 90℃ and react for 3 hours. Finally, separate the solid and liquid to obtain scandium concentrate with a Sc content of 50.1% and aluminum liquid. The scandium recovery rate is 99.5%.

[0055] The above steps yield scandium concentrate with a total recovery rate of 74.4% and a scandium content of 50.1%, achieving comprehensive recovery and utilization of titanium, sulfur, and aluminum elements.

[0056] Example 3 Strong magnetic tailings from a beneficiation plant in the Panzhihua area were used as the experimental raw material, and the contents of its main elements are shown in Table 1.

[0057] S1. Take vanadium-titanium magnetite tailings and adjust the slurry concentration to 6%. Then feed it into a CZ-150 hydrocyclone at a feed pressure of 0.15MPa for classification. The hydrocyclone cone angle is 11° and the overflow pipe diameter is 22mm. The hydrocyclone underflow and overflow are obtained. The underflow contains 0.4% -0.005mm material and the overflow contains 5.1% +0.01mm material. The underflow is ball-milled for classification. The average particle size of the obtained material is 0.008mm and the maximum particle size is 0.012mm. Then feed the ball-milled material into a vertical ring pulsating strong magnetic separator for separation. The magnetic field strength is 1.2T. Strong magnetic concentrate and tailings are obtained. The strong magnetic concentrate contains 7.83% TiO2 and 20.1g / t Sc. The strong magnetic tailings contain 1.9% TiO2 and 34.2g / t Sc.

[0058] S2. The strong magnetic concentrate obtained in step S1 is adjusted to a pulp concentration of 25% and fed into a shaking table for two separations: a rougher and a cleaner. This yields a gravity concentrate and tailings. The gravity concentrate contains 15.21% TiO2 and 10.22 g / t of Sc; the gravity tailings contain 1.87% TiO2 and 42.5 g / t of Sc. The strong magnetic tailings and gravity tailings are combined and fed into a flotation cell for desulfurization flotation. Sulfuric acid is added to adjust the pulp pH to 3.5. Then, diesel oil and No. 2 oil are added sequentially, stirred for 5 minutes, and aerated for skimming flotation, yielding an S content of 5.9% and S... C The sample consisted of sulfur concentrate with a selenium content of 3.6 g / t and desulfurization tailings with a selenium content of 0.05% and a saturation content of 41.2 g / t. Compared to strongly magnetic tailings, the scandium recovery rate in the desulfurization tailings was 79.2%.

[0059] S3. The desulfurized tailings from step S2 are filtered to a moisture content of 8.3% and fed into a rotary kiln for roasting. The roasting temperature is controlled at 1200℃ and the roasting time is 2 hours. After roasting, the material is immediately poured into water. The material temperature is reduced to 120℃ in 0.2 minutes. The cooled material is then separated into solid and liquid components. A 20% nitric acid solution is added to the solid-liquid mixture at a liquid-to-solid mass ratio of 2:1. The leaching reaction is carried out at 200℃ for 2 hours. After the reaction, the solid and liquid components are separated to obtain a leachate with a Sc content of 22.5 mg / L and an Al content of 7.2 g / L. The scandium leaching rate is 97.8%.

[0060] S4. Take the leachate from step S3, add 10% magnesium oxide slurry in a water bath at 40℃, adjust the pH of the reaction system to 3.8, and then stir for 3 hours. Finally, separate the solid and liquid to obtain aluminum scandium precipitate and mother liquor. The scandium content in the mother liquor is 0.2 mg / L, and the scandium precipitation rate is 99.10%. Take the aluminum scandium precipitate from step S4, add a solution with pH=7.5 for washing. After washing, the calcium and magnesium content in the precipitate is 0.26%. Then, add 20% sodium hydroxide solution at a liquid-to-solid mass ratio of 2.5:1, control the reaction temperature at 100℃, and react for 3 hours. Finally, separate the solid and liquid to obtain scandium concentrate with a Sc content of 50.6% and aluminum liquid. The scandium recovery rate is 99.6%.

[0061] The above steps yield scandium concentrate with a total recovery rate of 76.5% and a scandium content of 50.6%, achieving comprehensive recovery and utilization of titanium, sulfur, and aluminum.

[0062] Comparative Example 1 This comparative example does not combine the strong magnetic tailings from step S2 and the gravity separation tailings from step S3 into the flotation cell for desulfurization flotation.

[0063] Strong magnetic tailings from a beneficiation plant in the Panzhihua area were used as the experimental raw material, and the contents of its main elements are shown in Table 1.

[0064] S1. Take vanadium-titanium magnetite tailings and adjust the slurry concentration to 6%. Then feed it into a CZ-150 hydrocyclone at a feed pressure of 0.15MPa for classification. The hydrocyclone cone angle is 11° and the overflow pipe diameter is 22mm. The hydrocyclone underflow and overflow are obtained. The content of -0.005mm material in the hydrocyclone underflow is 0.4%, and the content of +0.01mm material in the overflow is 5.1%.

[0065] S2. Take the hydrocyclone sediment from step S1 and ball mill it for classification. The average particle size of the obtained material is 0.008 mm and the maximum particle size is 0.012 mm. Then, feed the ball-milled classified material into a vertical ring pulsating strong magnetic separator for separation. The magnetic field strength is 1.2 T. Strong magnetic concentrate and tailings are separated. The strong magnetic concentrate contains 7.83% TiO2 and 20.1 g / t Sc. The strong magnetic tailings contain 1.9% TiO2 and 34.2 g / t Sc.

[0066] S3. The strong magnetic concentrate obtained in step S2 is adjusted to a slurry concentration of 25% and fed into a shaking table for two separations: one roughing and one cleaning, to obtain gravity concentrate and tailings. The gravity concentrate contains 15.21% TiO2 and 10.22 g / t Sc; the gravity tailings contain 1.87% TiO2 and 42.5 g / t Sc.

[0067] S4. Combine the strong magnetic tailings from step S2 and the gravity separation tailings from step S3 and feed them into a flotation cell for desulfurization flotation. Add sulfuric acid to adjust the pulp pH to 3.5, then add diesel and No. 2 oil sequentially, stir for 5 minutes, and aerate for skimming flotation to obtain an S content of 5.9%. C The sample consisted of sulfur concentrate with a content of 3.6 g / t and desulfurization tailings with a sulfur content of 0.05% and a scandium content of 41.2 g / t. Compared to strongly magnetic tailings, the scandium recovery rate in the desulfurization tailings was 79.2%.

[0068] S5. The desulfurized tailings from step S4 were filtered to a moisture content of 8.3% and fed into a rotary kiln for roasting. The roasting temperature was controlled at 1200℃ and the roasting time was 2 hours. After roasting, the material was allowed to cool naturally to 120℃ after 4 hours. Then, a 20% nitric acid solution was added at a liquid-to-solid mass ratio of 2:1, and a leaching reaction was carried out at 200℃ for 2 hours. After the reaction, the solid and liquid were separated, and the Sc content was 12.6 mg / L, the Al content was 7.1 g / L, and the scandium leaching rate was only 66.5%. The test was terminated because the scandium leaching rate did not meet expectations.

[0069] Comparative Example 2 This comparative example does not combine the strong magnetic tailings from step S2 and the gravity separation tailings from step S3 into the flotation cell for desulfurization flotation, nor does it perform desulfurization tailings pressure filtration before feeding them into the rotary kiln for roasting.

[0070] Strong magnetic tailings from a beneficiation plant in the Panzhihua area were used as the experimental raw material, and the contents of its main elements are shown in Table 1.

[0071] S1. Take vanadium-titanium magnetite tailings and adjust the slurry concentration to 6%. Then feed it into a CZ-150 hydrocyclone at a feed pressure of 0.15MPa for classification. The hydrocyclone cone angle is 11° and the overflow pipe diameter is 22mm. The hydrocyclone underflow and overflow are obtained. The content of -0.005mm material in the hydrocyclone underflow is 0.4%, and the content of +0.01mm material in the overflow is 5.1%.

[0072] S2. Take the hydrocyclone sediment from step S1 and ball mill it for classification. The average particle size of the obtained material is 0.008 mm and the maximum particle size is 0.012 mm. Then, feed the ball-milled classified material into a vertical ring pulsating strong magnetic separator for separation. The magnetic field strength is 0.5 T. Strong magnetic concentrate and tailings are separated. The strong magnetic concentrate contains 8.83% TiO2 and 19.1 g / t Sc. The strong magnetic tailings contain 3.9% TiO2 and 20.5 g / t Sc.

[0073] S3. The strong magnetic concentrate obtained in step S2 is adjusted to a slurry concentration of 25% and fed into a shaking table for two separations: one roughing and one cleaning, to obtain gravity concentrate and tailings. The gravity concentrate contains 13.4% TiO2 and 13.22 g / t Sc; the gravity tailings contain 1.92% TiO2 and 42.5 g / t Sc.

[0074] S4. Combine the strong magnetic tailings from step S2 and the gravity separation tailings from step S3 and feed them into a flotation cell for desulfurization flotation. Add sulfuric acid to adjust the pulp pH to 3.5, then add diesel and No. 2 oil sequentially, stir for 5 minutes, and aerate for skimming flotation to obtain an S content of 5.9%. C The test included sulfur concentrate with a content of 3.6 g / t and desulfurization tailings with a S content of 0.05% and a SC content of 23.5 g / t. The scandium enrichment ratio in the desulfurization tailings was low, failing to meet expectations, and the test was discontinued.

[0075] Comparative Example 3 This comparative example does not combine the strong magnetic tailings from step S2 and the gravity separation tailings from step S3 into the flotation cell for desulfurization flotation.

[0076] Strong magnetic tailings from a beneficiation plant in the Panzhihua area were used as the experimental raw material, and the contents of its main elements are shown in Table 1.

[0077] S1. Take vanadium-titanium magnetite tailings and adjust the slurry concentration to 6%. Then feed it into a CZ-150 hydrocyclone at a feed pressure of 0.15MPa for classification. The hydrocyclone cone angle is 11° and the overflow pipe diameter is 22mm. The hydrocyclone underflow and overflow are obtained. The content of -0.005mm material in the hydrocyclone underflow is 0.4%, and the content of +0.01mm material in the overflow is 5.1%.

[0078] S2. Take the hydrocyclone sediment from step S1 and ball mill it for classification. The average particle size of the obtained material is 0.008 mm and the maximum particle size is 0.012 mm. Then, feed the ball-milled classified material into a vertical ring pulsating strong magnetic separator for separation. The magnetic field strength is 1.2 T. Strong magnetic concentrate and tailings are separated. The strong magnetic concentrate contains 7.83% TiO2 and 20.1 g / t Sc. The strong magnetic tailings contain 1.9% TiO2 and 34.2 g / t Sc.

[0079] S3. The strong magnetic concentrate obtained in step S2 is adjusted to a slurry concentration of 25% and fed into a shaking table for two separations: one roughing and one cleaning, to obtain gravity concentrate and tailings. The gravity concentrate contains 15.21% TiO2 and 10.22 g / t Sc; the gravity tailings contain 1.87% TiO2 and 42.5 g / t Sc.

[0080] S4. Combine the strong magnetic tailings from step S2 and the gravity separation tailings from step S3 and feed them into a flotation cell for desulfurization flotation. Add sulfuric acid to adjust the pulp pH to 3.5, then add diesel and No. 2 oil sequentially, stir for 5 minutes, and aerate for skimming flotation to obtain an S content of 5.9%. C The sample consisted of sulfur concentrate with a content of 3.6 g / t and desulfurization tailings with a sulfur content of 0.05% and a scandium content of 41.2 g / t. Compared to strongly magnetic tailings, the scandium recovery rate in the desulfurization tailings was 79.2%.

[0081] S5. The desulfurized tailings from step S4 are filtered to a moisture content of 8.3% and fed into a rotary kiln for roasting. The roasting temperature is controlled at 1200℃ and the roasting time is 2 hours. After roasting, the material is immediately poured into water. The material temperature drops to 120℃ in 0.2 minutes. Then, the cooled material is separated into solid and liquid components. A 20% concentration nitric acid solution is added to the mixture at a liquid-to-solid mass ratio of 2:1. The leaching reaction is carried out at 200℃ for 2 hours. After the reaction, the solid and liquid components are separated to obtain Sc content of 22.5 mg / L, Al content of 7.2 g / L, and scandium leaching rate of 97.8%.

[0082] S6. Take the leachate from step S5, add 10% magnesium oxide slurry in a water bath at 40℃, adjust the pH of the reaction system to 3.8, and then stir the reaction for 0.5 h. Finally, separate the solid and liquid to obtain aluminum scandium precipitate and mother liquor. The scandium content in the mother liquor is 5.8 mg / L, and the scandium precipitation rate is 75.4%. The experiment was terminated because the scandium precipitation rate did not meet expectations.

[0083] Comparative Example 4 This comparative example does not combine the strong magnetic tailings from step S2 and the gravity separation tailings from step S3 into the flotation cell for desulfurization flotation.

[0084] Strong magnetic tailings from a beneficiation plant in the Panzhihua area were used as the experimental raw material, and the contents of its main elements are shown in Table 1.

[0085] S1. Take vanadium-titanium magnetite tailings and adjust the slurry concentration to 6%. Then feed it into a CZ-150 hydrocyclone at a feed pressure of 0.15MPa for classification. The hydrocyclone cone angle is 11° and the overflow pipe diameter is 22mm. The hydrocyclone underflow and overflow are obtained. The content of -0.005mm material in the hydrocyclone underflow is 0.4%, and the content of +0.01mm material in the overflow is 5.1%.

[0086] S2. Take the hydrocyclone sediment from step S1 and ball mill it for classification. The average particle size of the obtained material is 0.008 mm and the maximum particle size is 0.012 mm. Then, feed the ball-milled classified material into a vertical ring pulsating strong magnetic separator for separation. The magnetic field strength is 1.2 T. Strong magnetic concentrate and tailings are separated. The strong magnetic concentrate contains 7.83% TiO2 and 20.1 g / t Sc. The strong magnetic tailings contain 1.9% TiO2 and 34.2 g / t Sc.

[0087] S3. The strong magnetic concentrate obtained in step S2 is adjusted to a slurry concentration of 25% and fed into a shaking table for two separations: one roughing and one cleaning, to obtain gravity concentrate and tailings. The gravity concentrate contains 15.21% TiO2 and 10.22 g / t Sc; the gravity tailings contain 1.87% TiO2 and 42.5 g / t Sc.

[0088] S4. Combine the strong magnetic tailings from step S2 and the gravity separation tailings from step S3 and feed them into a flotation cell for desulfurization flotation. Add sulfuric acid to adjust the pulp pH to 3.5, then add diesel and No. 2 oil sequentially, stir for 5 minutes, and aerate for skimming flotation to obtain an S content of 5.9%. C The sample consisted of sulfur concentrate with a content of 3.6 g / t and desulfurization tailings with a sulfur content of 0.05% and a scandium content of 41.2 g / t. Compared to strongly magnetic tailings, the scandium recovery rate in the desulfurization tailings was 79.2%.

[0089] S5. The desulfurized tailings from step S4 are filtered to a moisture content of 8.3% and fed into a rotary kiln for roasting. The roasting temperature is controlled at 1200℃ and the roasting time is 2 hours. After roasting, the material is immediately poured into water. The material temperature drops to 120℃ in 0.2 minutes. Then, the cooled material is separated into solid and liquid components. A 20% concentration nitric acid solution is added to the mixture at a liquid-to-solid mass ratio of 2:1. The leaching reaction is carried out at 200℃ for 2 hours. After the reaction, the solid and liquid components are separated to obtain Sc content of 22.5 mg / L, Al content of 7.2 g / L, and scandium leaching rate of 97.8%.

[0090] S6. Take the leachate from step S5, add 10% magnesium oxide slurry in a water bath at 40°C, adjust the pH of the reaction system to 3.8, stir the reaction for 3 hours, and finally separate the solid and liquid to obtain aluminum scandium precipitate and mother liquor. The scandium content in the mother liquor is 0.2 mg / L, and the scandium precipitation rate is 99.10%.

[0091] S7. Without washing, the aluminum-scandium precipitate from step S6 was directly added to a 20% sodium hydroxide solution at a liquid-to-solid mass ratio of 2.5:1. The reaction temperature was controlled at 100℃ for 3 hours. Finally, solid-liquid separation was performed to obtain scandium concentrate and aluminum liquid with a Sc content of 34.8%, and the scandium recovery rate was 99.4%. The scandium concentrate had a high content of impurity elements and a low scandium content.

[0092] The beneficial effects of implementing this invention include: (1) The invention adopts a combined pre-enrichment process of hydrocyclone desliming-strong magnetic separation-gravity separation-desulfurization flotation to enrich scandium in the strong magnetic tailings of vanadium-titanium magnetite, which can significantly reduce the amount of ore processed and the cost of subsequent processes, improve the overall economic benefits, and simultaneously recover titanium and sulfur elements, realizing the comprehensive recycling of resources.

[0093] (2) The invention adopts a blank roasting-pressurized leaching process, which can achieve efficient leaching of scandium without the need to add harmful additives. The process is green, environmentally friendly and pollution-free.

[0094] (3) The invention adopts a combination of adsorption precipitation and alkali refining process, and the scandium content in the prepared scandium concentrate is as high as 50% or more. The high-quality scandium product can be obtained by secondary dissolution-precipitation-calcination treatment. There is no need to use cumbersome processes such as extraction separation-washing-back-extraction-precipitation. The process is shorter and more operable.

[0095] The above are exemplary embodiments disclosed in this invention. The order of the disclosed embodiments is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. However, it should be noted that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of this invention (including the claims) is limited to these examples. Various changes and modifications can be made without departing from the scope defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular.

[0096] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of the different aspects of the invention as described above exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings, characterized in that, Includes the following steps: S1. Take vanadium-titanium magnetite tailings and adjust them to a predetermined concentration of slurry. Feed the slurry into a hydrocyclone to obtain underflow and overflow. After grinding and classifying the underflow, separate it with strong magnetic separation to obtain strong magnetic concentrate and strong magnetic tailings. S2. After gravity separation of the strong magnetic concentrate, titanium rough concentrate and gravity tailings are obtained. The strong magnetic tailings and gravity tailings are combined and then subjected to desulfurization flotation to obtain sulfur rough concentrate and desulfurization tailings. S3. After desulfurization tailings are filtered and roasted, the roasted material is mixed with acid solution and leached under pressure at a temperature of 180~220℃. Then, solid-liquid separation is performed to obtain leachate and leaching residue. S4. Take the leachate, add the precipitant and stir to react. Then, separate the solid and liquid to obtain the scandium precipitate product and the mother liquor. Take the scandium precipitate product, add the alkaline solution and stir to react. Then, separate the solid and liquid to obtain scandium concentrate and aluminum liquid.

2. The method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings according to claim 1, characterized in that, In step S1, the cone angle of the hydrocyclone is 10~12°, the overflow port diameter is 22~24mm, and the mass concentration of the slurry is controlled at 5~8%.

3. The method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings according to claim 1, characterized in that, In step S1, the feed pressure of the hydrocyclone is controlled at 0.1~0.15MPa, and the proportion of -0.005mm particle size material in the underflow is below 0.5%.

4. The method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings according to claim 1, characterized in that, In step S1, the grinding and classification control material particle size is ≤0.01mm, and the magnetic field strength of the strong magnetic separation is 0.8~1.2T.

5. The method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings according to claim 1, characterized in that, In step S2, the gravity separation includes one or more separation operations through a spiral chute and / or a shaking table to obtain titanium rough concentrate and gravity tailings, wherein the TiO2 content in the gravity tailings is ≤2wt%.

6. The method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings according to claim 1, characterized in that, In step S3, the roasting temperature of the desulfurized tailings is controlled at 1000~1200℃, the roasting time is controlled at 1~2h, and the roasted material is cooled to below 300℃ within 0.1~1min.

7. The method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings according to claim 1, characterized in that, In step S3, the acid solution includes sulfuric acid or nitric acid, the concentration of the acid solution is controlled at 15~20wt%, the leaching temperature is controlled at 180~220℃, the leaching time is controlled at 1~2h, and the scandium content in the obtained leaching solution is 20~25mg / L and the aluminum content is 5~8g / L.

8. The method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings according to claim 1, characterized in that, In step S4, the precipitant includes at least one of sodium hydroxide, ammonia, magnesium oxide, and calcium oxide. The precipitation process controls the reaction temperature to 30-50°C, the precipitation pH to 3.5-4.5, the stirring reaction time to 1-4 hours, and the scandium adsorption precipitation rate to be above 98.5%.

9. The method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings according to claim 1, characterized in that, In step S4, before adding the alkaline solution and stirring the reaction, the scandium precipitate product is washed multiple times with an alkaline solution of pH=7.5~8.5 until the calcium and magnesium content in the material is reduced to below 0.5wt% after washing.

10. The method for recovering and preparing scandium concentrate from vanadium-titanium magnetite strongly magnetic tailings according to claim 1, characterized in that, In step S4, the concentration of the alkaline solution is controlled at 15-20 wt%, the reaction temperature is 80-100℃, and the reaction time is 2-4 h.

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