A method for assisting vanadium leaching by alkali with nanometer and micrometer bubble solution mechanical activation

Abstract

The application provides a method for assisting vanadium leaching by alkali through mechanical activation of nanobubble solution, which comprises the following steps: (1) preparing a nanobubble-containing solution; (2) mixing vanadium slag and the nanobubble-containing solution and performing mechanical activation through ball milling to obtain an activated slurry; (3) mixing alkali and the activated slurry and introducing oxygen-containing gas to perform alkali leaching reaction and leach vanadium. The application firstly adopts nanobubbles and mechanical activation to jointly strengthen the destruction of vanadium-containing phase structure in vanadium slag and promote the oxidation of vanadium, and then realizes the oxidation and dissolution of vanadium through alkali leaching reaction of the obtained activated slurry, and finally obtains vanadium-containing solution and leaching tailings through solid-liquid separation after the reaction. The application realizes high-efficiency leaching of vanadium in vanadium slag under low-alkali-concentration and low-temperature conditions, and has the advantages of mild conditions, high vanadium extraction rate and easy industrialization and scale-up production.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vanadium metallurgy, and particularly relates to a method for extracting vanadium by using nanometer-microbubble solution mechanical activation assisted alkali leaching. BACKGROUND

[0002] Vanadium slag is a vanadium-rich material produced by blowing vanadium-containing molten iron in the presence of oxygen gas. In the steel industry, vanadium slag produced from vanadium-titanium magnetite is the main raw material for extracting vanadium. Enterprises that produce iron and vanadium products from vanadium-titanium magnetite currently all use the traditional sodium roasting process to extract vanadium from vanadium slag. Sodium roasting-water leaching is the mainstream method for extracting vanadium from vanadium slag. The basic principle of the sodium roasting process is to use Na2CO3 as an additive to convert low-valence vanadium into water-soluble sodium salt of pentavalent vanadium through high-temperature sodium roasting (750-850℃), and then directly water leaching the sodium roasting product to obtain a leaching solution containing vanadium, and then adding an ammonium salt to obtain ammonium polyvanadate precipitate, and finally obtaining vanadium oxide product through reduction roasting. The sodium roasting process has low vanadium recovery rate, with a single roasting vanadium recovery rate of about 70%, and the vanadium recovery rate is only 80% after multiple roasting; the roasting temperature is high (750-850℃), and multiple roasting is required, resulting in high energy consumption; harmful HCl, Cl2 and other corrosive gases are generated during roasting, polluting the environment.

[0003] Although CN1884597A and CN86108218A and the like make different improvements to the additives and temperature regime of the sodium roasting process, the basic principles are the same, and the problems of high roasting temperature and the like of the traditional process cannot be avoided. CN101161831A proposes a method for calcium roasting of vanadium slag. Compared with the sodium roasting process, calcium roasting does not require a gradual temperature increase from low to high temperature, but direct high-temperature roasting, which makes the temperature of the roasting furnace easier to control, shortens the roasting time, and improves the production capacity of the equipment. However, the roasting temperature of calcium roasting is still very high (600-950℃), and the vanadium conversion rate is still less than 80%.

[0004] In order to improve resource utilization and reduce reaction energy consumption, wet vanadium extraction from vanadium slag has gradually developed into a clean and energy-saving new method.

[0005] CN102127655A discloses a method for decomposing vanadium slag at normal pressure by NaOH solution, with a reaction temperature of 180-260℃. Compared with the roasting process, the vanadium extraction process has significantly reduced temperature and energy consumption, and significantly increased vanadium extraction efficiency. However, due to the high alkali concentration of 80%, the evaporation energy consumption of the circulating alkali solution is very large.

[0006] CN101812588A discloses a method for decomposing vanadium slag at normal pressure by KOH solution, with a reaction temperature of 180-260℃. The temperature is greatly reduced, but the disadvantage is that the potassium hydroxide medium has high cost, and the generated potassium vanadate is not an industrial product and needs to be further separated and purified.

[0007] CN102127656A discloses a method for liquid-phase oxidative decomposition of vanadium slag. By using sodium hydroxide and sodium nitrate media, the oxidative decomposition process of vanadium slag is enhanced. Compared with sodium hydroxide molten salt media, the reaction temperature is lower, but the introduction of sodium nitrate media increases the number of subsequent separation steps.

[0008] CN111575495B discloses a method for the oxidative decomposition of vanadium slag enhanced by microbubbles in NaOH solution. The NaOH solution concentration is 30-40wt%, and the temperature is 100-140℃. The NaOH solution concentration and reaction temperature are significantly reduced. The disadvantage is that the aeration device is prone to clogging and needs to be replaced frequently, which is not conducive to continuous industrial production.

[0009] Therefore, it is necessary to further achieve efficient oxidative extraction of vanadium from vanadium slag under low temperature and low alkali concentration conditions. Summary of the Invention

[0010] To solve the above-mentioned technical problems, the present invention provides a method for vanadium extraction by alkaline leaching assisted by mechanical activation of nano-micro bubble solution. The method can be carried out under normal pressure, with mild reaction conditions, high vanadium leaching rate in vanadium slag under low alkali concentration and low temperature conditions, good operating environment, and no dust or waste gas generation.

[0011] To achieve this objective, the present invention adopts the following technical solution:

[0012] This invention provides a method for vanadium extraction by alkaline leaching assisted by mechanical activation of nano-micro bubble solution, the method comprising the following steps:

[0013] (1) Prepare a solution containing nano-microbubbles;

[0014] (2) The first mixed vanadium slag and the solution containing nano-microbubbles are ball-milled for mechanical activation to obtain an activated slurry;

[0015] (3) The second mixed alkali and the activated slurry are introduced, and oxygen-containing gas is introduced to carry out the alkali leaching reaction to leach vanadium.

[0016] The vanadium in the vanadium slag provided by this invention mainly exists in the form of vanadium spinel. By introducing nanobubbles, the oxygen solubility in the solution can be significantly increased, enhancing the oxidation capacity of the solution and promoting the oxidative decomposition of low-valent vanadium in the vanadium spinel. Compared with ordinary bubbles, nanobubbles have a longer residence time in the solution and can adhere to the surface of the vanadium slag. When they burst during mechanical activation, the high pressure inside them generates a local cavitation effect, which not only has a certain shearing effect on the minerals, but also generates highly oxidizing active oxygen substances, including hydrogen peroxide, hydroxyl radicals, and superoxide radicals, during the bursting process. This can further enhance the oxidation reaction of the vanadium-containing phase in the vanadium slag and improve the vanadium extraction rate.

[0017] This invention employs a combination of nano-microbubbles, mechanical activation, and alkaline leaching to extract vanadium, which significantly reduces the alkali concentration and temperature required for vanadium extraction and enables the reaction to occur under normal pressure. This approach has broad prospects for industrial application and significantly reduces production equipment and operating costs.

[0018] Preferably, the solution containing nano-microbubbles in step (1) is an alkaline solution containing nano-microbubbles, and more preferably an alkaline solution saturated with nano-microbubbles.

[0019] Preferably, the gas content in the solution containing nanobubbles is 1–25 v%. For example, it can be 1 v%, 4 v%, 8 v%, 10 v%, 12 v%, 16 v%, 20 v%, or 25 v%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, with 8–20 v% being preferred. The present invention further preferably controls the gas content in the solution containing nanobubbles within the above range, which can better ensure the vanadium extraction effect.

[0020] Preferably, the solution containing nano-microbubbles in step (1) is a sodium hydroxide solution and / or a potassium hydroxide solution, preferably a sodium hydroxide solution.

[0021] Preferably, the alkali concentration in the solution containing nano-microbubbles is 0-30 wt%, for example, it can be 0 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or 30 wt%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 0-20 wt%.

[0022] Preferably, the preparation of the solution containing nano-microbubbles in step (1) includes: introducing nano-microbubbles into an alkaline solution or an aqueous solution.

[0023] Preferably, the diameter of the introduced nanobubbles is ≤100μm. For example, the diameter of the nanobubbles can be 1-200nm, 300-500nm, 800nm-1μm or 50μm-100μm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable. Preferably, the diameter is ≤1μm.

[0024] Preferably, the time for introducing nanobubbles into the alkaline solution or aqueous solution is 2 to 60 minutes, for example, 2 minutes, 3 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 50 minutes, or 60 minutes, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable. The preferred time is 30 to 60 minutes.

[0025] Preferably, the vanadium slag mentioned in step (2) is the vanadium slag produced by converter blowing during the smelting of vanadium-titanium magnetite.

[0026] Preferably, the vanadium content in the vanadium slag, calculated as vanadium pentoxide, is 8 to 20 wt%, for example, it can be 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0027] Preferably, the vanadium slag further contains any one or at least two combinations of Cr, Fe, Ti, Si, Mg, Ca, Mn or Al, wherein typical but non-limiting combinations are the combination of Cr and Fe, the combination of Ti and Fe, the combination of Cr and Al, the combination of Si and Fe, the combination of Ca and Mn, and the combination of Mn and Fe.

[0028] The vanadium slag of this invention contains vanadium-iron spinel, which has a complex mineral phase structure and is difficult to transform, making vanadium extraction difficult.

[0029] Preferably, the ratio of the solution containing nano-microbubbles to vanadium slag is 0.1 to 5 ml / g, for example, it can be 0.1 ml / g, 0.5 ml / g, 1 ml / g, 1.5 ml / g, 2 ml / g, 2.5 ml / g, 3 ml / g, 3.5 ml / g, 4 ml / g, 4.5 ml / g or 5 ml / g, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 0.5 to 2 ml / g.

[0030] Preferably, the mechanical activation time in step (2) is 10 to 240 min, for example, it can be 10 min, 20 min, 40 min, 60 min, 80 min, 100 min, 120 min, 140 min, 160 min, 180 min, 200 min, 220 min or 240 min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 20 to 120 min.

[0031] Preferably, the ball-to-particle ratio for mechanical activation is 10:1 to 35:1, for example, it can be 10:1, 15:1, 20:1, 25:1, 30:1 or 35:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 15:1 to 30:1.

[0032] Preferably, the rotation speed for mechanical activation is 200 to 600 rpm, for example, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm or 600 rpm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 300 to 500 rpm.

[0033] Preferably, the particle size of the vanadium slag in the activated slurry in step (2) is 13 to 48 μm, for example, it can be 13 μm, 18 μm, 23 μm, 28 μm, 33 μm, 38 μm, 43 μm or 48 μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 18 to 38 μm.

[0034] Preferably, the temperature of the alkaline leaching reaction in step (3) is 30 to 130°C, for example, it can be 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C or 130°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 50 to 100°C.

[0035] Preferably, the concentration of the alkaline solution in the alkaline leaching reaction is 5-40 wt%, for example, it can be 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, 30 wt%, 35 wt%, or 40 wt%, etc., preferably 5-20 wt%.

[0036] This invention utilizes a solution containing nano-microbubbles for mechanical activation-assisted alkaline leaching of vanadium, enabling vanadium leaching at low temperatures and low alkali concentrations, significantly reducing energy and alkali consumption.

[0037] Preferably, the alkaline solution used in the alkaline leaching reaction is a sodium hydroxide solution and / or a potassium hydroxide solution, with sodium hydroxide solution being the most preferred.

[0038] Preferably, the alkaline leaching reaction time is 1 to 7 hours, for example, it can be 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours or 7 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 3 to 5 hours.

[0039] Preferably, the liquid-to-solid ratio of the alkaline leaching reaction is 2 to 10 ml / g, for example, it can be 2 ml / g, 3 ml / g, 4 ml / g, 5 ml / g, 6 ml / g, 7 ml / g, 8 ml / g, 9 ml / g or 10 ml / g, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 3 to 6 ml / g.

[0040] Preferably, the oxygen-containing gas in step (3) includes any one or a combination of at least two of air, oxygen-enriched air, or oxygen.

[0041] Preferably, the oxygen-containing gas is added by continuous flow.

[0042] Preferably, the flow rate of the oxygen-containing gas continuously introduced is 0.1 to 1.5 L / min, for example, it can be 0.1 L / min, 0.2 L / min, 0.3 L / min, 0.5 L / min, 0.8 L / min, 1.0 L / min, 1.2 L / min or 1.5 L / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] In this invention, "atmospheric pressure" refers to a pressure environment without pressurization or depressurization, similar to atmospheric pressure. Depending on geographical location, altitude, and temperature, its absolute pressure range is generally between 98 and 102 kPa. The method for vanadium extraction using nano-microbubble solution-assisted mechanical activation in this invention can be carried out under atmospheric pressure, with mild reaction conditions.

[0044] As a preferred technical solution of the present invention, the method includes the following steps:

[0045] (1) A nano-micro bubble generator was used to introduce nano-micro bubbles with a bubble diameter ≤100μm into an alkaline solution with a concentration of 0-30wt% to obtain a solution containing nano-micro bubbles;

[0046] (2) Mechanical activation was carried out by ball milling the first mixed vanadium slag with a liquid-solid ratio of 0.1 to 5 ml / g and the solution containing nano-micro bubbles. The mechanical activation time was 10 to 240 min, the ball-to-material ratio was 10:1 to 35:1, and the rotation speed was 200 to 600 rpm, to obtain an activated slurry containing vanadium slag with a particle size of 13 to 48 μm.

[0047] (3) The second mixed alkali and the activated slurry are mixed to form an alkali solution with a concentration of 5-40 wt%, and oxygen-containing gas is continuously introduced at a flow rate of 0.1-1.5 L / min to carry out the alkali leaching reaction. The temperature of the alkali leaching reaction is 30-130℃, the time is 1-7 h, and the liquid-solid ratio is 2-10 ml / g to leach vanadium. After solid-liquid separation, vanadium-containing leachate is obtained.

[0048] The present invention does not limit the solid-liquid separation described herein, and any method known to those skilled in the art for solid-liquid separation can be used, and adjustments can be made according to actual conditions, such as filtration, sedimentation or centrifugation.

[0049] This invention does not limit the nano-bubble generator; any bubble generator known to those skilled in the art that can be used to generate nano-bubbles can be used, and adjustments can be made according to actual conditions.

[0050] Compared with the prior art, the present invention has at least the following beneficial effects:

[0051] (1) The method for vanadium extraction by alkali leaching using nano-micro bubble solution mechanical activation provided by the present invention causes vanadium slag to undergo lattice distortion and dislocation under mechanical activation. At the same time, the arrangement of particles in the lattice loses its periodicity and forms lattice defects, which leads to an increase in lattice internal energy, changes in surface properties and enhanced reactivity, thereby significantly improving the leaching efficiency of vanadium slag. The vanadium extraction rate is ≥88%, and under preferred conditions it reaches more than 95%, and can reach more than 99% at the highest. The process is highly economical. Moreover, the content of impurity elements after extraction is as low as less than 6.53 ppm, indicating that the separation effect of vanadium from other elements in the present invention is excellent.

[0052] (2) The method of vanadium extraction by alkali leaching using mechanical activation of nano-micro bubble solution provided by the present invention can significantly increase the oxygen solubility in alkaline solution and increase the oxidation capacity of solution with the participation of nano-micro bubbles. At the same time, due to the high internal pressure of nano-micro bubbles, local cavitation effect will be generated when nano-micro bubbles burst during mechanical activation. This will not only further exert a shearing effect on the mineral, but also stimulate the generation of substances with strong oxidation activity during the bursting process, further strengthening the destruction of vanadium-containing phase structure in vanadium slag and improving the oxidation efficiency of vanadium.

[0053] (3) The method for vanadium extraction by alkaline leaching using nano-micro bubble solution mechanical activation provided by the present invention does not require pre-calcination, thus avoiding the generation of waste gas during the calcination process, and does not generate any dust or waste gas that is harmful to the environment during the reaction process.

[0054] (4) Compared with the existing alkaline wet vanadium extraction method, the method of vanadium extraction by mechanical activation of nano-micro bubble solution provided by the present invention reduces the reaction temperature to below 130℃, or even below 100℃, which is more than 60℃ lower than the existing technology. The NaOH concentration is reduced to below 40wt%, and can reach 20wt%. It truly realizes atmospheric pressure, low temperature and low alkali leaching. It is a green, economical and efficient vanadium extraction method, which is of great significance for the efficient and clean extraction of vanadium slag. Attached Figure Description

[0055] Figure 1 This is a comparison diagram of the solution before and after the introduction of air bubbles in Example 1 of the present invention. Detailed Implementation

[0056] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0057] It should be understood that in the description of this invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0058] In one specific embodiment, the present invention provides a method for vanadium extraction by alkaline leaching assisted by mechanical activation of nano-micro bubble solution, the method comprising the following steps:

[0059] (1) A nano-micro bubble generator was used to introduce nano-micro bubbles with a bubble diameter ≤100μm into an alkaline solution with a concentration of 0-30wt% to obtain a solution containing nano-micro bubbles;

[0060] (2) Mechanical activation was carried out by ball milling the first mixed vanadium slag with a liquid-solid ratio of 0.1 to 5 ml / g and the solution containing nano-micro bubbles. The mechanical activation time was 10 to 240 min, the ball-to-material ratio was 10:1 to 35:1, and the rotation speed was 200 to 600 rpm, to obtain an activated slurry containing vanadium slag with a particle size of 13 to 48 μm.

[0061] (3) The second mixed alkali and the activated slurry are mixed to form an alkali solution with a concentration of 5-40 wt%, and oxygen-containing gas is continuously introduced at a flow rate of 0.1-1.5 L / min to carry out the alkali leaching reaction. The temperature of the alkali leaching reaction is 30-130℃, the time is 1-7 h, and the liquid-solid ratio is 2-10 ml / g to leach vanadium. After solid-liquid separation, vanadium-containing leachate is obtained.

[0062] It should be clarified that any use of the process provided in the embodiments of the present invention or any substitution or change of conventional data falls within the protection and disclosure scope of the present invention.

[0063] Example 1

[0064] This embodiment provides a method for vanadium extraction by alkaline leaching assisted by mechanical activation of nano-micro bubble solution, the method comprising the following steps:

[0065] (1) A nano-microbubble with a bubble diameter ≤1μm was introduced into a sodium hydroxide solution with a concentration of 20wt% using a nano-microbubble generator to obtain a nano-microbubble solution with a gas content of 11.3v%.

[0066] (2) The solution saturated with nano-micro bubbles and vanadium slag with a V2O5 content of 10.5wt% were added to a ball mill at a liquid-solid ratio of 2:1 for mechanical activation. The mechanical activation time was 120 min, the ball-to-material ratio was 25:1, and the rotation speed was 400 rpm, to obtain an activated slurry containing vanadium slag with an average particle size of 18 μm.

[0067] (3) Transfer the activated slurry to the reactor, add sodium hydroxide solution to the concentration of 20wt%, carry out the alkaline leaching reaction, and continuously introduce oxygen at a flow rate of 1L / min. The alkaline leaching reaction temperature is 90℃, the time is 5h, the liquid-solid ratio is 5ml / g, and after filtration, vanadium-containing leaching solution and leaching residue are obtained.

[0068] The nanobubble-saturated solution obtained in this embodiment, such as... Figure 1 As shown, the solution before the bubbles are introduced is as follows: Figure 1 As shown in Figure A, the solution after the introduction of air bubbles is as follows: Figure 1 As shown in Figure B, the solution saturated with nanobubbles is milky white, containing a large number of bubbles, and this is confirmed by a dissolved oxygen analyzer. Figure 1 The oxygen solubility in solution B is 49 mg / L, which is much higher than that in the solution obtained through a 0.22 μm aeration head (oxygen solubility is about 15 mg / L). The solution filled with nano-microbubbles shows a significant increase in oxygen solubility / oxygen content, which, in synergy with the mechanical activation process, improves the extraction rate of vanadium from vanadium slag.

[0069] Example 2

[0070] This embodiment provides a method for vanadium extraction by alkaline leaching assisted by mechanical activation of nano-micro bubble solution, the method comprising the following steps:

[0071] (1) A nano-microbubble generator was used to introduce nano-microbubbles with a bubble diameter ≤1μm into a sodium hydroxide solution with a concentration of 10wt%, and a nano-microbubble solution with a gas content of 14.7v% was obtained.

[0072] (2) The solution saturated with nano-micro bubbles and vanadium slag with a V2O5 content of 9.3wt% were added to a ball mill at a liquid-solid ratio of 1:1 for mechanical activation. The mechanical activation time was 240 min, the ball-to-material ratio was 20:1, and the rotation speed was 400 rpm, to obtain an activated slurry containing vanadium slag with an average particle size of 9μm.

[0073] (3) Transfer the activated slurry to the reactor, add sodium hydroxide solution to the concentration of 15wt%, carry out the alkaline leaching reaction, and continuously introduce air at a flow rate of 1L / min. The alkaline leaching reaction temperature is 80℃, the time is 5h, the liquid-solid ratio is 5ml / g, and after centrifugation, vanadium-containing leaching solution and leaching residue are obtained.

[0074] Example 3

[0075] This embodiment provides a method for vanadium extraction by alkaline leaching assisted by mechanical activation of nano-micro bubble solution, the method comprising the following steps:

[0076] (1) A nano-microbubble generator was used to introduce nano-microbubbles with a bubble diameter ≤1μm into a sodium hydroxide solution with a concentration of 15wt%, and a nano-microbubble solution with a gas content of 13.2v% was obtained.

[0077] (2) The solution saturated with nano-micro bubbles and vanadium slag with a V2O5 content of 12.4wt% were added to a ball mill at a liquid-solid ratio of 1:1 for mechanical activation. The mechanical activation time was 90 min, the ball-to-material ratio was 30:1, and the rotation speed was 300 rpm, to obtain an activated slurry containing vanadium slag with an average particle size of 23 μm.

[0078] (3) Transfer the activated slurry to the reactor, add sodium hydroxide solution to the concentration of 20wt%, carry out alkaline leaching reaction, and continuously introduce oxygen-enriched air (oxygen content 20v%) at a flow rate of 1L / min. The alkaline leaching reaction temperature is 100℃, the time is 5h, the liquid-solid ratio is 5ml / g, and after centrifugation, vanadium-containing leaching solution and leaching residue are obtained.

[0079] Example 4

[0080] This embodiment provides a method for vanadium extraction by alkaline leaching assisted by mechanical activation of nano-micro bubble solution, the method comprising the following steps:

[0081] (1) A nano-microbubble with a bubble diameter ≤1μm was introduced into a sodium hydroxide solution with a concentration of 10wt% using a nano-microbubble generator to obtain a nano-microbubble solution with a gas content of 17.4v%.

[0082] (2) The solution saturated with nano-micro bubbles and vanadium slag with a V2O5 content of 10.5wt% were added to a ball mill at a liquid-solid ratio of 0.5:1 for mechanical activation. The mechanical activation time was 90 min, the ball-to-material ratio was 15:1, and the rotation speed was 500 rpm, to obtain an activated slurry containing vanadium slag with an average particle size of 22 μm.

[0083] (3) Transfer the activated slurry to the reactor, add sodium hydroxide solution to the concentration of 10wt%, carry out the alkaline leaching reaction, and continuously introduce oxygen at a flow rate of 1L / min. The alkaline leaching reaction temperature is 70℃, the time is 5h, the liquid-solid ratio is 5ml / g, and after filtration, vanadium-containing leaching solution and leaching residue are obtained.

[0084] Example 5

[0085] This embodiment provides a method for alkali leaching vanadium using mechanical activation assisted by nano-micro bubble solution. Except for the sodium hydroxide solution concentration of 0 wt% in step (1), the method is the same as in Example 1.

[0086] Example 6

[0087] This embodiment provides a method for alkali leaching vanadium using mechanical activation assisted by nano-micro bubble solution. Except for the mechanical activation time of 20 min in step (2) to obtain an activated slurry containing vanadium slag with an average particle size of 38 μm, the method is the same as in Example 1.

[0088] Example 7

[0089] This embodiment provides a method for alkali leaching vanadium using mechanical activation assisted by nano-micro bubble solution. Except for the nano-micro bubbles introduced in step (1) having an average diameter of 1 to 100 μm, the method is the same as in Example 1.

[0090] Example 8

[0091] This embodiment provides a method for vanadium extraction by alkaline leaching assisted by mechanical activation of nano-micro bubble solution. Except that the alkaline solution is potassium hydroxide solution, the method is the same as in Example 3.

[0092] Example 9

[0093] This embodiment provides a method for alkali leaching vanadium using mechanical activation assisted by nano-micro bubble solution. Except for step (1), in which the time for introducing nano-micro bubbles is only 5 minutes, resulting in a gas content of only 4.4v% in the solution, the method is the same as in Example 1.

[0094] Comparative Example 1

[0095] This embodiment provides a method for alkali leaching vanadium using mechanical activation assisted by nano-micro bubble solution. The method is the same as in Example 1 except that nano-micro bubbles are not introduced in step (1).

[0096] Comparative Example 2

[0097] This embodiment provides a method for vanadium extraction by alkaline leaching using mechanical activation of nano-micro bubble solution. Except for step (2), which does not involve mechanical activation, the method is the same as in Example 1.

[0098] Comparative Example 3

[0099] This embodiment provides a method for alkali leaching vanadium using mechanical activation assisted by nano-micro bubble solution. The method is the same as in Embodiment 1 except that nano-micro bubbles are not introduced and mechanical activation is not performed in steps (1) and (2).

[0100] Comparative Example 4

[0101] This embodiment provides a method for alkali leaching vanadium using mechanical activation assisted by nano-micro bubble solution. The method is the same as in Embodiment 1 except that step (1) is omitted and nano-micro bubbles are introduced during the mechanical activation process in step (2).

[0102] Due to equipment limitations, it is difficult to implement this comparative example by simultaneously introducing nano-microbubbles and performing mechanical activation.

[0103] Comparative Example 5

[0104] This embodiment provides a method for vanadium extraction by alkaline leaching using mechanical activation of nano-microbubble solution. The method is the same as in Example 1 except that step (1) is omitted and oxygen-containing gas is continuously introduced in the form of nano-microbubbles during the alkaline leaching reaction in step (3).

[0105] Test method: The mass of the tailings and the vanadium content in the above examples and comparative examples were detected by ICP method, and the vanadium extraction rate was calculated based on the mass of the raw materials and the content of each element therein. The results are shown in Table 1.

[0106] Table 1

[0107]

[0108] In Table 1, "-" indicates that there is no relevant data.

[0109] As can be seen from Table 1:

[0110] (1) As can be seen from the comprehensive examples 1-9, the method of vanadium extraction by mechanical activation with nano-micro bubble solution provided by the present invention can achieve vanadium extraction well, with an extraction rate of ≥88%, reaching more than 95% under preferred conditions, and up to 99% at the highest, and the process is highly economical; moreover, the content of impurity elements after extraction is as low as 6.53ppm, indicating that the separation effect of vanadium from other elements in the present invention is good.

[0111] (2) It can be seen from the combined examples 1 and 5 that the concentration of sodium hydroxide in step (1) of example 1 is 20 wt%, compared with the concentration of sodium hydroxide in step (1) of example 5 being 0 wt%. The extraction rate of vanadium in example 1 is 99%, while the extraction rate of vanadium in example 5 is 98%. This shows that the solution containing nano-microbubbles in the present invention can also achieve excellent extraction effect without alkali.

[0112] (3) As can be seen from the combined examples 1 and 6, the mechanical activation time in Example 1 was 120 min, and an activated slurry containing vanadium slag with an average particle size of 18 μm was obtained. In Example 6, the mechanical activation time was 20 min, and an activated slurry containing vanadium slag with an average particle size of 38 μm was obtained. The vanadium extraction rate in Example 1 was 99%, and the vanadium extraction rate in Example 6 was 93%. This shows that by further controlling the mechanical activation time and vanadium slag particle size within a certain range, the extraction rate of vanadium can be further improved.

[0113] (4) It can be seen from the combined examples 1 and 7 that the diameter of the nano-microbubbles introduced in Example 1 is ≤1μm, and the diameter of the nano-microbubbles introduced in Example 7 is 1~100μm. The vanadium extraction rate in Example 1 is 99%, and the vanadium extraction rate in Example 7 is only 90%. This shows that the present invention can further improve the vanadium extraction rate by further controlling the size of the introduced nano-microbubbles within the preferred range.

[0114] (5) As can be seen from the combined examples 1 and 9, the gas content of the nano-microbubble solution obtained in Example 1 is 11.3%, while that in Example 9 is 4.4%. The vanadium extraction rate in Example 1 is 99%, while that in Example 9 is 88%. This shows that the present invention achieves a higher vanadium extraction rate by further controlling the gas content of the introduced nano-microbubble solution within a preferred range. (6) As can be seen from the combined examples 1 and 1, Example 1 uses nano-microbubbles to introduce into the reaction alkaline solution. Compared with the absence of nano-microbubbles in 1, the vanadium extraction rate in Example 1 is 99%, while that in 1 is 84%. This shows that the introduction of nano-microbubbles improves the vanadium extraction rate. That is, the present invention utilizes the method of nano-microbubble-assisted mechanical activation to increase the oxygen solubility in the solution and the strong oxidizing active substances generated by bubble rupture, thereby significantly improving the vanadium extraction rate.

[0115] (7) It can be seen from the combined results of Example 1 and Comparative Example 2 that Example 1 uses mechanical activation to enhance the extraction of vanadium. Compared with Comparative Example 2, which does not use mechanical activation, the extraction rate of vanadium in Example 1 is 99%, and the extraction rate of vanadium in Comparative Example 2 is 73%. This shows that mechanical activation improves the extraction rate of vanadium. That is, the present invention uses mechanical activation to cause vanadium slag to undergo lattice distortion and dislocation. At the same time, the arrangement of particles in the lattice loses its periodicity and forms lattice defects, which leads to an increase in the internal energy of the lattice, changes in surface properties, and enhanced reactivity, thereby improving the extraction rate of vanadium.

[0116] (8) Combining Example 1 and Comparative Example 3, it can be seen that Example 1 uses nano-microbubbles to assist mechanical activation. Compared with Comparative Example 3, which does not introduce nano-microbubbles and does not perform mechanical activation, the vanadium extraction rate in Example 1 is 99%, and the vanadium extraction rate in Comparative Example 3 is 68%. This shows that the synergistic effect of nano-microbubbles and mechanical activation significantly improves the vanadium extraction rate. That is, the mechanical activation method of this invention causes lattice distortion and dislocation in vanadium slag, and at the same time, the particle arrangement in the lattice loses its periodicity, forming lattice defects, resulting in increased lattice internal energy, changed surface properties, and enhanced reactivity. On this basis, nano-microbubbles are introduced to strengthen the mechanical activation process. That is, after the nano-microbubbles break under mechanical activation, the oxygen in the bubbles can oxidize the low-valence vanadium in vanadium spinel, promoting the decomposition of vanadium spinel. At the same time, during the nano-microbubble breaking process, strong oxidizing active substances are generated, including hydrogen peroxide, hydroxyl radicals, and superoxide radicals, which can strengthen the oxidation reaction of vanadium-containing phases in vanadium slag and improve the vanadium extraction rate.

[0117] (9) In Comparative Example 5, oxygen-containing gas was continuously introduced in the form of nano-microbubbles during the alkaline leaching reaction in step (3). Since the aeration device is in direct contact with the mechanically activated fine vanadium slag, it is easy to cause blockage of the aeration device, thus reducing the amount of oxygen-containing gas introduced and the vanadium leaching rate. Moreover, the alkaline leaching reaction time is much longer than the time for producing nano-microbubbles, which increases oxygen consumption and increases process costs.

[0118] In summary, the method for vanadium extraction by alkaline leaching using nano-microbubble solution mechanical activation provided by this invention employs mechanical activation to disrupt the mineral phase structure of vanadium slag and improve its reactivity. Furthermore, nano-microbubbles are introduced to enhance the mechanical activation process, further strengthening the oxidation reaction of vanadium-containing phases in the vanadium slag by increasing oxygen solubility in the solution and promoting the production of highly oxidizing substances during the bursting process, thereby improving vanadium extraction. By further employing specific mechanical activation time, particle size of the mechanically activated vanadium slag, sodium hydroxide concentration during alkaline leaching, and alkaline leaching reaction temperature, under optimal conditions, the vanadium extraction rate can exceed 99%, resulting in high economic benefits.

[0119] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for vanadium extraction by alkaline leaching assisted by mechanical activation of nano-micro bubble solution, characterized in that, The method includes the following steps: (1) Prepare a solution containing nano-microbubbles; (2) The first mixed vanadium slag and the solution containing nano-microbubbles are ball-milled for mechanical activation to obtain an activated slurry; (3) The second mixed alkali and the activated slurry are subjected to an alkaline leaching reaction by introducing oxygen-containing gas to leach vanadium; The preparation of the solution containing nano-microbubbles in step (1) includes: introducing nano-microbubbles into an alkaline solution or an aqueous solution.

2. The method according to claim 1, characterized in that, The solution containing nano-microbubbles mentioned in step (1) is an alkaline solution containing nano-microbubbles.

3. The method according to claim 1, characterized in that, The solution containing nano-microbubbles mentioned in step (1) is an alkaline solution saturated with nano-microbubbles.

4. The method according to claim 1, characterized in that, The gas content in the solution containing nano-microbubbles is 1~25v.

5. The method according to claim 1, characterized in that, The gas content in the solution containing nano-microbubbles is 8~20v.

6. The method according to claim 1, characterized in that, The solution containing nano-microbubbles mentioned in step (1) is a sodium hydroxide solution and / or a potassium hydroxide solution.

7. The method according to claim 1, characterized in that, The solution containing nano-microbubbles mentioned in step (1) is a sodium hydroxide solution.

8. The method according to claim 1, characterized in that, The alkali concentration in the solution containing nano-microbubbles is 0~30wt%.

9. The method according to claim 1, characterized in that, The alkali concentration in the solution containing nano-microbubbles is 0~20wt%.

10. The method according to claim 1, characterized in that, The diameter of the introduced nanobubbles is ≤100μm.

11. The method according to claim 1, characterized in that, The diameter of the introduced nanobubbles is ≤1μm.

12. The method according to claim 1, characterized in that, The time for introducing nanobubbles into the alkaline solution or aqueous solution is 2 to 60 minutes.

13. The method according to claim 1, characterized in that, The vanadium slag mentioned in step (2) is the vanadium slag produced by converter blowing during the smelting process of vanadium-titanium magnetite.

14. The method according to claim 1, characterized in that, The ratio of the solution containing nano-microbubbles to vanadium slag is 0.1~5 ml / g.

15. The method according to claim 1, characterized in that, The ratio of the solution containing nano-microbubbles to vanadium slag is 0.5~2 ml / g.

16. The method according to claim 1, characterized in that, The mechanical activation time in step (2) is 10~240 min.

17. The method according to claim 1, characterized in that, The mechanical activation time in step (2) is 20~120 min.

18. The method according to claim 1, characterized in that, The ball-to-material ratio for mechanical activation is 10:1 to 35:

1.

19. The method according to claim 1, characterized in that, The ball-to-material ratio for mechanical activation is 15:1 to 30:

1.

20. The method according to claim 1, characterized in that, The mechanical activation speed is 200~600 rpm.

21. The method according to claim 1, characterized in that, The mechanical activation speed is 300~500 rpm.

22. The method according to claim 1, characterized in that, The particle size of the vanadium slag in the activated slurry in step (2) is 13~48μm.

23. The method according to claim 1, characterized in that, The particle size of the vanadium slag in the activated slurry in step (2) is 18~38μm.

24. The method according to claim 1, characterized in that, The temperature of the alkaline leaching reaction in step (3) is 30~130℃.

25. The method according to claim 1, characterized in that, The temperature of the alkaline leaching reaction in step (3) is 50~100℃.

26. The method according to claim 1, characterized in that, The concentration of the alkaline solution in the alkaline leaching reaction is 5~40wt%.

27. The method according to claim 1, characterized in that, The concentration of the alkaline solution in the alkaline leaching reaction is 5~20wt%.

28. The method according to claim 1, characterized in that, The alkaline solution used in the alkaline leaching reaction is a sodium hydroxide solution and / or a potassium hydroxide solution.

29. The method according to claim 1, characterized in that, The alkaline solution used in the alkaline leaching reaction is a sodium hydroxide solution.

30. The method according to claim 1, characterized in that, The alkaline leaching reaction takes 1 to 7 hours.

31. The method according to claim 1, characterized in that, The alkaline leaching reaction takes 3-5 hours.

32. The method according to claim 1, characterized in that, The liquid-to-solid ratio of the alkaline leaching reaction is 2~10 ml / g.

33. The method according to claim 1, characterized in that, The liquid-to-solid ratio of the alkaline leaching reaction is 3~6 ml / g.

34. The method according to claim 1, characterized in that, The oxygen-containing gas mentioned in step (3) includes any one or a combination of at least two of air, oxygen-enriched air, or oxygen.

35. The method according to claim 1, characterized in that, The oxygen-containing gas is added continuously.

36. The method according to claim 35, characterized in that, The oxygen-containing gas is continuously introduced at a flow rate of 0.1~1.5 L / min.

37. The method according to any one of claims 1 to 36, characterized in that, The method includes the following steps: (1) A nano-micro bubble generator is used to introduce nano-micro bubbles with a bubble diameter ≤100μm into an alkaline solution with a concentration of 0~30wt% to obtain a solution containing nano-micro bubbles; (2) Mechanical activation was carried out by ball milling the first mixed vanadium slag with a liquid-to-solid ratio of 0.1~5 ml / g and the solution containing nano-micro bubbles. The mechanical activation time was 10~240 min, the ball-to-material ratio was 10:1~35:1, and the rotation speed was 200~600 rpm, to obtain an activated slurry containing vanadium slag with a particle size of 13~48 μm. (3) The second mixed alkali and the activated slurry are mixed to form an alkali solution with a concentration of 5~40wt%, and oxygen-containing gas is continuously introduced at a flow rate of 0.1~1.5L / min to carry out the alkali leaching reaction. The temperature of the alkali leaching reaction is 30~130℃, the time is 1~7h, and the liquid-solid ratio is 2~10ml / g to leach vanadium. After solid-liquid separation, vanadium-containing leachate is obtained.

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