Method for deeply extracting vanadium from vanadium-containing steel slag

Abstract

The invention provides a method for deeply extracting vanadium from vanadium-containing steel slag, which comprises the following steps: mixing the vanadium-containing steel slag and an oxygen-containing microbubble ammonium bicarbonate solution, and carrying out mechanochemical ball milling activation to carry out leaching reaction to obtain a vanadium extracting solution. According to the method, advanced oxidation is cooperated with mechanochemical ball milling to activate and strengthen deep extraction of vanadium in the vanadium-containing steel slag, wrapping of substances such as calcium silicate and calcium titanium oxide on a vanadium-containing solid solution phase is destroyed through mechanical activation, and O2 microbubbles in an ammonium bicarbonate medium are promoted to generate active oxygen under excitation of mechanical activation energy; exposure reaction and deep oxidation extraction of a vanadium-containing phase under mild conditions are achieved, the content of V2O5 in tailings after vanadium extraction is smaller than or equal to 0.5%, and the vanadium extraction rate is 83% or above.

Description

Technical Field

[0001] The invention relates to the technical field of vanadium chemical metallurgy, and in particular to a method for deep extraction of vanadium from vanadium-containing steel slag. Background Art

[0002] Vanadium is an important metal, widely used as an alloy additive in the steel industry, a catalyst in the chemical industry, and a battery material in the field of new energy. Vanadium-containing steel slag is a solid waste produced in the steelmaking process of vanadium-titanium magnetite, with an annual production of more than 10 million tons, usually containing 1-5% V 2 O 5 There are two main sources and production methods of vanadium-containing steel slag. The first method is that the vanadium remaining in the semi-steel enters the slag after being oxidized during the steelmaking process, forming V 2 O 5 The second way is to directly make steel with molten iron without blowing vanadium slag to obtain vanadium-containing slag with a content of less than 1.5%. 2 O 5 Vanadium-containing steel slag. The characteristics of vanadium-containing steel slag are mainly reflected in the following three aspects: (1) low vanadium grade, high iron and calcium oxide content, complete crystal structure, dense texture, and poor dissociation degree; (2) complex and fluctuating composition, mainly composed of calcium silicate, spinel, calcium titanium oxide, magnesium-ferrite, metallic iron, free oxide, etc.; (3) vanadium valence state is complex and dispersed in a variety of mineral phases, the occurrence state is complex, and vanadium extraction is difficult. These characteristics make it extremely difficult to efficiently extract vanadium from vanadium-containing steel slag, and there is no report on industrial application so far.

[0003] Existing research on vanadium extraction technology from vanadium-containing steel slag can be divided into the following three categories: (1) Acid leaching: Using strong acids such as sulfuric acid and hydrochloric acid to leach vanadium-containing steel slag can achieve a high vanadium recovery rate. However, this method has problems such as high acid consumption, poor selectivity, and equipment corrosion, and the obtained calcium sulfate slag cannot be used; (2) Alkaline leaching: Using strong alkalis such as sodium hydroxide for leaching. Although vanadium can be extracted in some cases, it requires high temperature and high pressure conditions, which makes it difficult to achieve industrial application; (3) High-temperature roasting / reduction: Treating vanadium-containing steel slag by high-temperature roasting or reduction is limited by the high calcium content in vanadium-containing steel slag, which is easy to generate difficult-to-leach calcium vanadate, affecting the extraction of vanadium.

[0004] CN107287431A proposes a method of mixing vanadium-containing steel slag and 5wt% sodium bicarbonate solution, reacting in a pressure reactor, with a carbon dioxide partial pressure of 1MPa, a reaction temperature of 175°C, a leaching pressure of 1.3MPa, and a reaction time of 1.4h, under which the leaching rate of vanadium can reach more than 90%. The reaction needs to be carried out under high temperature and high pressure conditions, has high requirements for equipment, and has a large investment cost.

[0005] CN107090549A proposes to extract vanadium from vanadium-containing steel slag by using a method of low-temperature sodium roasting-pressure acid leaching. Mix vanadium-containing steel slag and sodium carbonate, add auxiliary agents, roasting temperature 850°C, roasting time 50min to obtain roasted sand. Subsequently, the roasted sand is subjected to pressure acid leaching under the conditions of pressure 1.5MPa, leaching temperature 210°C, sulfuric acid mass concentration 25%, leaching time 50min, and liquid-solid ratio 1.2mL / g, and the leaching rate of vanadium can reach 83%. However, this method has high energy consumption and high production cost. It needs to be leached under high temperature and pressure strong acid conditions later. The reaction conditions are harsh, the acid consumption is large, and the selectivity of sulfuric acid is poor, which will lead to more impurities in the vanadium-containing solution, which brings difficulties to subsequent treatment.

[0006] Vanadium in vanadium-containing steel slag exists in three valence states: V(III), V(IV) and V(V). High-valent vanadium accounts for about 80-90% of the total vanadium, and trivalent vanadium accounts for about 10-20%. Due to the presence of this part of insoluble low-valent vanadium, the vanadium in vanadium-containing steel slag cannot be deeply leached. The use of oxidative leaching to oxidize low-valent vanadium into high-valent vanadium and realize its dissolution is an effective way to increase the vanadium yield. Wan Junfeng et al. increased the leaching rate of vanadium in vanadium-containing steel slag to 88.1% under the conditions of reaction temperature of 200°C, alkali concentration of 50wt%, and oxygen partial pressure of 0.2Mpa. Feng Guangxi et al. proposed the "sodium roasting-carbonation leaching" process, which oxidized the low-valent vanadium in vanadium-containing steel slag into high-valent vanadium through sodium roasting, and dissolved the vanadium in the liquid phase through subsequent carbonation leaching, thereby realizing the extraction of vanadium, with a leaching rate of about 80%. Although the above method realizes the conversion of low-valent vanadium to high-valent vanadium in vanadium-containing steel slag and improves the vanadium leaching rate to a certain extent, the reaction conditions are harsh and require high temperature, high pressure and high concentration of leaching agent or high energy consumption roasting process, and it is impossible to achieve efficient deep leaching of vanadium under mild conditions.

[0007] Therefore, it is urgent to develop a new process for extracting vanadium from vanadium-containing steel slag that is mild, efficient and easy to operate. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a method for deep extraction of vanadium from vanadium-containing steel slag, which can realize efficient extraction of vanadium from vanadium-containing steel slag under mild conditions and has broad application prospects.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] The invention provides a method for deep vanadium extraction from vanadium-containing steel slag, which comprises the following steps: mixing the vanadium-containing steel slag and an oxygen-containing microbubble ammonium bicarbonate solution and activating the mixture through mechanochemical ball milling to perform a leaching reaction to obtain a vanadium extraction solution.

[0011] It is worth noting that, unlike ordinary vanadium slag, which has a low calcium content, the reasons why it is difficult to extract vanadium from vanadium-containing steel slag are mainly reflected in three aspects: first, the CaO content in vanadium-containing steel slag is high, which will combine with vanadium during the reaction to form insoluble calcium vanadate, reducing the leaching rate of vanadium. Therefore, how to deal with the adverse effects caused by the high calcium problem is the key to improving the leaching rate of vanadium; second, the valence state of vanadium in vanadium-containing steel slag is diverse, and low-valent vanadium is difficult to leach and needs to be converted into high-valent vanadium through oxidation and other means; third, the vanadium in vanadium-containing steel slag mainly coexists in the form of solid solution with complex minerals mainly composed of calcium silicate and calcium titanium oxide, so the key to achieving vanadium extraction is to strengthen the decomposition of the solid solution phase.

[0012] The present invention has found that compared with acid leaching and alkaline leaching, the use cost of ammonium bicarbonate is low, the reaction conditions are mild, and the selective separation of vanadium and calcium in vanadium-containing steel slag can be achieved. 4 + It can be directly used as a subsequent vanadium precipitant, avoiding the introduction of other ions and has industrial prospects.

[0013] In order to achieve efficient extraction of vanadium and solve the two core problems of vanadium phase being encapsulated and low-priced vanadium being difficult to extract, the present invention proposes to strengthen the extraction of vanadium from vanadium-containing steel slag by using advanced oxidation in coordination with mechanochemical activation. On the one hand, mechanochemical ball milling activation can break the mineral phase structure, expose vanadium from the solid solution, and facilitate the oxidation and leaching of vanadium. At the same time, it can effectively reduce the particle size and increase the surface area, which leads to an increase in active sites and enhances the contact and reaction mass transfer process between steel slag particles and leachate, thereby promoting the leaching of vanadium. On the other hand, under the excitation of mechanical activation energy, the O in the ammonium bicarbonate medium is promoted. 2 Microbubbles generate active oxygen, and through the synergistic effect of mechanical activation and advanced oxidation, the exposure reaction and deep oxidation extraction of vanadium-containing phases under mild conditions are achieved. 2 O 5 The content is ≤0.3%, and the vanadium extraction rate can reach nearly 90%.

[0014] Preferably, the oxygen content in the oxygen-containing microbubble ammonium bicarbonate solution is 1 to 30 v%, for example, it can be 1 v%, 3 v%, 5 v%, 8 v%, 10 v%, 12 v%, 15 v%, 25 v% or 30 v%, etc., as well as specific point values ​​between the above values. Due to space limitations and for the sake of simplicity, the present invention will no longer list them exhaustively, and preferably 10 to 25 v% to better ensure the vanadium extraction effect.

[0015] Preferably, the diameter of the oxygen microbubbles in the ammonium bicarbonate solution containing oxygen microbubbles is ≤50 μm, for example, it can be 1-100 nm, 100-300 nm, 300-500 nm, 800 nm-1 μm, 1-10 μm, 10-30 μm or 30-50 μm. As well as specific point values ​​between the above values, the present invention will not be exhaustively listed due to space limitations and for the sake of simplicity, and the preferred diameter is ≤1 μm.

[0016] Preferably, the concentration of ammonium bicarbonate in the oxygen-containing microbubble ammonium bicarbonate solution is 25 to 60 wt%, for example, it can be 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt% or 60 wt%, as well as specific point values ​​between the above values. Due to space limitations and for the sake of simplicity, the present invention will no longer list them exhaustively.

[0017] The present invention preferably controls the concentration of ammonium bicarbonate within the above range to achieve a better leaching effect. When the concentration of ammonium bicarbonate is high, the solution viscosity increases, affecting the ion diffusion and mass transfer process, thereby reducing the leaching rate; the amount of leaching agent increases, increasing the production cost; promoting the chemical equilibrium to the reverse reaction direction, inhibiting the leaching of vanadium; increasing the solubility of impurities, and increasing the difficulty of subsequent separation and purification. When the concentration of ammonium bicarbonate is low, there is insufficient leaching reaction power, slowing down the leaching reaction rate, and reducing the leaching efficiency; the basic conditions for the reaction cannot be met, resulting in the leaching reaction cannot be carried out effectively or can only be carried out to a certain extent, and the expected leaching target cannot be achieved, and the leaching is incomplete.

[0018] Preferably, the preparation of the oxygen-containing microbubble ammonium bicarbonate solution comprises: preparing it using a micro-nano bubble generator to obtain a freshly prepared oxygen-containing microbubble ammonium bicarbonate solution.

[0019] Preferably, the prepared oxygen-containing microbubble ammonium bicarbonate solution is placed for a time of less than or equal to 5 minutes and then transferred to the leaching reaction. For example, it can be 1s, 20s, 30s, 40s, 50s, 60s, 1.2min, 1.5min, 1.8min, 2.0min, 2.2min, 2.5min, 2.8min, 3.0min, 3.2min, 3.5min, 3.8min, 4.0min, 4.2min, 4.5min, 4.8min or 5.0min, etc.

[0020] Through research, it is found that the stability of oxygen bubbles in the oxygen-containing microbubble ammonium bicarbonate solution is general, and in order to make full use of the initial aggregation and rupture effects of oxygen bubbles, the present invention preferably controls the transfer to the leaching reaction within 5 minutes after preparation.

[0021] Preferably, the preparation of the oxygen-containing microbubble ammonium bicarbonate solution comprises: introducing oxygen into the ammonium bicarbonate solution using a micro-nano bubble generator.

[0022] Preferably, the liquid-to-solid ratio of the oxygen-containing microbubble ammonium bicarbonate solution to the vanadium-containing steel slag is (2-10):1 mL / g, for example, it can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, as well as specific point values ​​between the above values. Due to space limitations and for the sake of simplicity, the present invention will no longer list them exhaustively.

[0023] Preferably, the particle size of the vanadium-containing steel slag is 38-150 μm, for example, it can be 38-45 μm, 45-74 μm, 74-104 μm or 104-150 μm, as well as specific point values ​​between the above values. Due to space limitations and for the sake of simplicity, the present invention will no longer list them exhaustively.

[0024] Preferably, the mass fraction of vanadium in the vanadium-containing steel slag as vanadium pentoxide is 1 to 5wt%, for example, it can be 1wt%, 1.2wt%, 1.4wt%, 1.5wt%, 1.8wt%, 2.0wt%, 2.2wt%, 2.5wt%, 2.8wt%, 3.0wt%, 3.5wt%, 3.8wt%, 4.0wt%, 4.2wt% or 5.0wt%, etc., as well as specific point values ​​between the above values. Due to space limitations and for the sake of simplicity, the present invention will no longer list them exhaustively.

[0025] Preferably, the mass fraction of calcium in the vanadium-containing steel slag as calcium oxide is 20 to 50 wt%, for example, it can be 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt% or 50 wt%, etc., as well as specific point values ​​between the above values. Due to space limitations and for the sake of simplicity, the present invention will no longer list them exhaustively.

[0026] It is worth noting that, those skilled in the art understand that, in the process of vanadium extraction, the higher the calcium content in the raw material, the more difficult it is to extract vanadium; those skilled in the art believe that for every 1wt% increase in calcium content, the vanadium extraction rate will decrease by about 4.7-9.0%, because the presence of calcium will not only lead to the formation of calcium vanadate, which reduces the extraction of vanadium on the one hand, but also the newly formed precipitate will wrap the raw material, thereby further reducing the extraction of vanadium; moreover, the calcium in the steel slag exists in the form of calcium silicate, calcium ferrite, calcium titanium oxide and other phases, which have a stable crystal structure, and vanadium is wrapped therein in the form of a solid solution, making it difficult for vanadium to contact with the leaching agent, inhibiting the leaching reaction of vanadium and reducing the vanadium extraction efficiency; in addition, the presence of calcium will also lead to an increase in the consumption of the leaching agent, thereby increasing the cost of vanadium extraction.

[0027] Preferably, the vanadium-containing steel slag also includes phases such as vanadium-containing calcium silicate, calcium ferrite and calcium titanium oxide.

[0028] Preferably, the vanadium-containing steel slag contains trivalent vanadium, tetravalent vanadium and pentavalent vanadium.

[0029] Preferably, trivalent vanadium in the vanadium-containing steel slag accounts for 10-20% of the mass of all vanadium elements, for example, it can be 10%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0030] Preferably, the sum of tetravalent vanadium and pentavalent vanadium in the vanadium-containing steel slag accounts for 80-90% of the mass of all vanadium elements, for example, it can be 80%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89% or 90%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0031] Preferably, the ball-to-material ratio of the mechanochemical ball milling activation is (3-30):1, for example, it can be 3:1, 5:1, 7:1, 10:1, 15:1, 20:1, 25:1 or 30:1, as well as specific point values ​​between the above values. Due to space limitations and for the sake of simplicity, the present invention will no longer list them exhaustively.

[0032] Preferably, the diameter of the grinding balls activated by mechanochemical ball milling is 10-15 mm, accounting for 22-28%, for example, it can be 22%, 22.3%, 22.5%, 23%, 24%, 25%, 26.5%, 27% or 28%, etc., 5-8 mm accounts for 54-64%, for example, it can be 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63% or 64%, etc., 1-3 mm accounts for 14-18%, for example, it can be 14%, 14.5%, 15%, 16%, 16.5%, 17%, 17.5% or 18%, etc.

[0033] Preferably, the ball milling speed of the mechanochemical ball milling activation is 100-600 rpm, for example, it can be 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm or 600 rpm, as well as specific point values ​​between the above values. Due to space limitations and for the sake of simplicity, the present invention will no longer list them exhaustively.

[0034] Preferably, the time of the mechanochemical ball milling activation is 30 to 120 min, for example, it can be 30 min, 45 min, 60 min, 75 min, 90 min or 120 min, as well as specific point values ​​between the above values. Due to space limitations and for the sake of simplicity, the present invention will no longer list them exhaustively.

[0035] Preferably, the temperature of the leaching reaction is 30-60°C, for example, it can be 30°C, 34°C, 37°C, 40°C, 44°C, 47°C, 50°C, 54°C, 57°C or 60°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0036] Preferably, the pressure of the leaching reaction is normal pressure, generally between 95 and 105 kPa.

[0037] The invention can realize the extraction of vanadium-containing steel slag containing a large amount of calcium at low temperature and normal pressure by synergistically adopting an oxygen-containing ammonium bicarbonate solution and mechanochemical activation, and the leaching rate is high.

[0038] Preferably, the pH of the leaching reaction is 7 to 9, for example, 7, 7.3, 7.5, 7.7, 7.9, 8.2, 8.4, 8.6, 8.8 or 9, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0039] As a preferred technical solution of the present invention, the method comprises the following steps:

[0040] (1) introducing oxygen into an ammonium bicarbonate solution by using a micro-nano bubble generator to obtain a freshly prepared oxygen-containing micro-bubble ammonium bicarbonate solution; wherein the oxygen content is 1 to 30% by volume, the diameter of the oxygen micro-bubbles is ≤50 μm, and the concentration of ammonium bicarbonate is 25 to 60% by weight;

[0041] (2) After the prepared oxygen-containing microbubble ammonium bicarbonate solution is placed for a period of less than or equal to 5 minutes, the prepared oxygen-containing microbubble ammonium bicarbonate solution and vanadium-containing steel slag with a particle size of 38 to 150 μm are immediately mixed at a liquid-to-solid ratio of (2 to 10):1, and the mixture is activated by mechanochemical ball milling at a temperature of 30 to 60° C., a pH of 7 to 9, and a ball milling speed of 100 to 600 rpm to carry out a leaching reaction for 30 to 120 minutes. The ball-to-material ratio is (3 to 30):1, and the diameters of the grinding balls are 10 to 15 mm, accounting for 22 to 28%, 5 to 8 mm, accounting for 54 to 64%, and 1 to 3 mm, accounting for 14 to 18%. After the leaching reaction, the materials are subjected to solid-liquid separation to obtain vanadium extraction liquid and vanadium extraction tailings.

[0042] The present invention has no special limitation on the solid-liquid separation in the above process. Any device and method for solid-liquid separation known to those skilled in the art can be used, and can also be adjusted according to the actual process, such as filtration, centrifugation or sedimentation separation, or a combination of different methods.

[0043] Compared with the prior art, the present invention has at least the following beneficial effects:

[0044] (1) The method for deep vanadium extraction from vanadium-containing steel slag provided by the present invention performs oxidation and ball milling leaching simultaneously, effectively realizing the enhanced leaching means of oxidation, ball milling and leaching at the same time. The two cooperate with each other. Under the optimal conditions, the leaching rate of vanadium in the vanadium-containing steel slag is greatly increased to more than 83%, the vanadium content in the vanadium extraction tailings is within 0.5wt%, preferably within 0.3wt%, and the calcium content in the vanadium extraction solution is less than 54mg / L;

[0045] (2) The method for deep vanadium extraction from vanadium-containing steel slag provided by the present invention can utilize HO· generated near the microbubble generation point to enhance the oxidation ability, effectively convert the insoluble low-valent vanadium in the vanadium-containing steel slag into soluble high-valent vanadium, thereby improving the leaching rate of vanadium;

[0046] (3) The method for deep vanadium extraction from vanadium-containing steel slag provided by the present invention can, firstly, change the crystal structure, break the solid solution phase of vanadium, expose vanadium, and promote the oxidation and leaching of vanadium; secondly, effectively reduce the particle size and increase the specific surface area, which leads to an increase in active sites and enhances the contact and reaction mass transfer process between the steel slag particles and the leachate, thereby promoting the leaching of vanadium; thirdly, avoid the calcium carbonate coating layer generated during the reaction process to hinder the further leaching of vanadium and reduce the reaction kinetics;

[0047] (4) The method for deep vanadium extraction from vanadium-containing steel slag provided by the present invention uses ammonium bicarbonate as a leaching agent, calcium and carbonate ions combine to form calcium carbonate which enters the solid phase to achieve calcium solidification, and vanadium and ammonium ions combine to form ammonium metavanadate which enters the liquid phase, thereby achieving efficient separation of vanadium and calcium in vanadium-containing steel slag. DETAILED DESCRIPTION

[0048] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0049] For example, the vanadium-containing steel slag used in the embodiments of the present invention and the comparative examples has a composition of 2.08 wt% V in terms of oxides. 2 O 5 , 29.04wt% CaO, 21.77wt% TFe, 12.20wt% MgO, 8.47wt% SiO 2 、2.55wt%Al 2 O 3 and 1.63wt%TiO 2 .

[0050] Example 1

[0051] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag, the method comprising the following steps:

[0052] (1) introducing oxygen into an ammonium bicarbonate solution by using a micro-nano bubble generator to obtain an oxygen-containing microbubble ammonium bicarbonate solution; wherein the oxygen content is 25% by volume, the diameter of the oxygen microbubbles is ≤1 μm, and the concentration of ammonium bicarbonate is 40% by weight;

[0053] (2) Immediately (within 5 minutes) mix the oxygen-containing microbubble ammonium bicarbonate solution prepared in step (1) and vanadium-containing steel slag with a particle size of 45 to 74 μm at a liquid-to-solid ratio of 4:1, and subject the mixture to mechanochemical ball milling activation for 60 minutes at normal pressure, a temperature of 40°C, a pH of 7.5, and a ball milling speed of 400 rpm to carry out a leaching reaction. The ball-to-material ratio is 30:1, and the diameters of the grinding balls are 10 to 15 mm, accounting for 25%, 5 to 8 mm, accounting for 60%, and 1 to 3 mm, accounting for 15%. After the leaching reaction, the material is filtered to obtain a vanadium extraction liquid and a vanadium extraction tailing.

[0054] Example 2

[0055] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag, the method comprising the following steps:

[0056] (1) introducing oxygen into an ammonium bicarbonate solution by using a micro-nano bubble generator to obtain an oxygen-containing micro-bubble ammonium bicarbonate solution; wherein the oxygen content is 30% by volume, the diameter of the oxygen micro-bubbles is ≤1 μm, and the concentration of ammonium bicarbonate is 40% by weight;

[0057] (2) Immediately (within 5 minutes) mix the oxygen-containing microbubble ammonium bicarbonate solution prepared in step (1) and vanadium-containing steel slag with a particle size of 45 to 74 μm at a liquid-to-solid ratio of 7:1, and subject the mixture to mechanochemical ball milling activation for 120 minutes at normal pressure, a temperature of 45° C., a pH of 7.8, and a ball milling speed of 400 rpm, wherein the ball-to-material ratio is 20:1, and the diameters of the grinding balls are 10 to 15 mm, accounting for 28%, 5 to 8 mm, accounting for 56%, and 1 to 3 mm, accounting for 16%. After the leaching reaction, the material is filtered to obtain vanadium extraction liquid and vanadium extraction tailings.

[0058] Example 3

[0059] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag, the method comprising the following steps:

[0060] (1) introducing oxygen into an ammonium bicarbonate solution by using a micro-nano bubble generator to obtain an oxygen-containing micro-bubble ammonium bicarbonate solution; wherein the oxygen content is 20% by volume, the diameter of the oxygen micro-bubbles is ≤0.5 μm, and the concentration of ammonium bicarbonate is 50% by weight;

[0061] (2) Immediately (within 5 minutes) mix the oxygen-containing microbubble ammonium bicarbonate solution prepared in step (1) and vanadium-containing steel slag with a particle size of 38 to 45 μm at a liquid-to-solid ratio of 7:1, and subject the mixture to mechanochemical ball milling activation for 60 minutes at normal pressure, a temperature of 50° C., a pH of 7.8, and a ball milling speed of 500 rpm to carry out a leaching reaction. The ball-to-material ratio is 30:1, and the diameters of the grinding balls are 10 to 15 mm, accounting for 26%, 5 to 8 mm, accounting for 59%, and 1 to 3 mm, accounting for 15%. After the leaching reaction, the material is filtered to obtain a vanadium extraction liquid and a vanadium extraction tailing.

[0062] Example 4

[0063] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag, the method comprising the following steps:

[0064] (1) introducing oxygen into an ammonium bicarbonate solution by using a micro-nano bubble generator to obtain an oxygen-containing micro-bubble ammonium bicarbonate solution; wherein the oxygen content is 25% by volume, the diameter of the oxygen micro-bubbles is ≤1 μm, and the concentration of ammonium bicarbonate is 50% by weight;

[0065] (2) Immediately (within 5 minutes) mix the oxygen-containing microbubble ammonium bicarbonate solution prepared in step (1) and vanadium-containing steel slag with a particle size of 45 to 74 μm at a liquid-to-solid ratio of 4:1, and subject the mixture to mechanochemical ball milling activation for 90 minutes at normal pressure, a temperature of 45°C, a pH of 8, and a ball milling speed of 200 rpm, wherein the ball-to-material ratio is 10:1, and the diameters of the grinding balls are 10 to 15 mm, accounting for 24%, 5 to 8 mm, accounting for 59%, and 1 to 3 mm, accounting for 17%. After the leaching reaction, the material is filtered to obtain vanadium extraction liquid and vanadium extraction tailings.

[0066] Example 5

[0067] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag, the method comprising the following steps:

[0068] (1) introducing oxygen into an ammonium bicarbonate solution by using a micro-nano bubble generator to obtain an oxygen-containing micro-bubble ammonium bicarbonate solution; wherein the oxygen content is 15% by volume, the diameter of the oxygen micro-bubbles is ≤0.5 μm, and the concentration of ammonium bicarbonate is 40% by weight;

[0069] (2) Immediately (within 5 minutes) mix the oxygen-containing microbubble ammonium bicarbonate solution prepared in step (1) and vanadium-containing steel slag with a particle size of 38 to 45 μm at a liquid-to-solid ratio of 8:1, and subject the mixture to mechanochemical ball milling activation for 90 minutes at normal pressure, a temperature of 30° C., a pH of 8.5, and a ball milling speed of 400 rpm to carry out a leaching reaction. The ball-to-material ratio is 30:1, and the diameters of the grinding balls are 10 to 15 mm, accounting for 22%, 5 to 8 mm, accounting for 64%, and 1 to 3 mm, accounting for 14%. After the leaching reaction, the material is filtered to obtain a vanadium extraction liquid and a vanadium extraction tailing.

[0070] Example 6

[0071] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag, the method comprising the following steps:

[0072] (1) introducing oxygen into an ammonium bicarbonate solution by using a micro-nano bubble generator to obtain an oxygen-containing micro-bubble ammonium bicarbonate solution; wherein the oxygen content is 15% by volume, the diameter of the oxygen micro-bubbles is ≤1 μm, and the concentration of ammonium bicarbonate is 60% by weight;

[0073] (2) Immediately (within 5 minutes) mix the oxygen-containing microbubble ammonium bicarbonate solution prepared in step (1) and vanadium-containing steel slag with a particle size of 38 to 45 μm at a liquid-to-solid ratio of 6:1, and subject the mixture to mechanochemical ball milling activation for 60 minutes at normal pressure, a temperature of 35° C., a pH of 7.2, and a ball milling speed of 500 rpm, wherein the ball-to-material ratio is 30:1, and the diameters of the grinding balls are 10 to 15 mm, accounting for 28%, 5 to 8 mm, accounting for 54%, and 1 to 3 mm, accounting for 18%. After the leaching reaction, the material is filtered to obtain vanadium extraction liquid and vanadium extraction tailings.

[0074] Example 7

[0075] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag, the method comprising the following steps:

[0076] (1) introducing oxygen into an ammonium bicarbonate solution by using a micro-nano bubble generator to obtain an oxygen-containing micro-bubble ammonium bicarbonate solution; wherein the oxygen content is 30% by volume, the diameter of the oxygen micro-bubbles is ≤1 μm, and the concentration of ammonium bicarbonate is 35% by weight;

[0077] (2) Immediately (within 5 minutes) mix the oxygen-containing microbubble ammonium bicarbonate solution prepared in step (1) and vanadium-containing steel slag with a particle size of 74 to 150 μm at a liquid-to-solid ratio of 10:1, and subject the mixture to mechanochemical ball milling activation for 30 minutes at normal pressure, a temperature of 60° C., a pH of 9, and a ball milling speed of 600 rpm to carry out a leaching reaction. The ball-to-material ratio is 3:1, and the diameters of the grinding balls are 10 to 15 mm, accounting for 24%, 5 to 8 mm, accounting for 60%, and 1 to 3 mm, accounting for 16%. After the leaching reaction, the material is filtered to obtain a vanadium extraction liquid and a vanadium extraction tailing.

[0078] Example 8

[0079] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method is identical to that of embodiment 3 except that the concentration of ammonium bicarbonate in the oxygen-containing microbubble ammonium bicarbonate solution is 20 wt %.

[0080] Example 9

[0081] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method is identical to that of embodiment 3 except that the concentration of ammonium bicarbonate in the oxygen-containing microbubble ammonium bicarbonate solution is 70 wt %.

[0082] Example 10

[0083] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method is identical to the third embodiment except that the oxygen content in the oxygen-containing microbubble ammonium bicarbonate solution is 0.5 v%.

[0084] Embodiment 11

[0085] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method is identical to the third embodiment except that the oxygen content in the oxygen-containing microbubble ammonium bicarbonate solution is 40v%.

[0086] Example 12

[0087] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method has the same conditions as those of Embodiment 3 except that the liquid-to-solid ratio of the oxygen-containing microbubble ammonium bicarbonate solution to the vanadium-containing steel slag is 13:1 mL / g.

[0088] Embodiment 13

[0089] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method has the same conditions as those of Embodiment 3 except that the liquid-to-solid ratio of the oxygen-containing microbubble ammonium bicarbonate solution to the vanadium-containing steel slag is 1:1 mL / g.

[0090] Embodiment 14

[0091] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method has the same conditions as those of embodiment 3 except that the ball-to-material ratio during mechanochemical ball milling activation is 40:1.

[0092] Embodiment 15

[0093] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method has the same conditions as those of embodiment 3 except that the ball-to-material ratio during mechanochemical ball milling activation is 2:1.

[0094] Example 16

[0095] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method has the same conditions as those in Embodiment 3 except that the ball milling speed for mechanochemical ball milling activation is 700 rpm.

[0096] Embodiment 17

[0097] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method is identical to that of embodiment 3 except that the ball milling speed for mechanochemical ball milling activation is 50 rpm.

[0098] Embodiment 18

[0099] This embodiment provides a method for deep extraction of vanadium from vanadium-containing steel slag. Except that all grinding balls with a diameter of 5 to 8 mm are used, other conditions are exactly the same as those of embodiment 3.

[0100] Comparative Example 1

[0101] This comparative example provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method is the same as Example 3 except that the oxygen-containing microbubble ammonium bicarbonate solution is replaced by an ammonium bicarbonate solution of equal concentration.

[0102] Comparative Example 2

[0103] This comparative example provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method is the same as Example 3 except that ball milling is not performed and only stirring is performed at 500 rpm for leaching reaction.

[0104] Comparative Example 3

[0105] This comparative example provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method is the same as Example 3 except that the ammonium bicarbonate solution in step (1) is replaced by a sodium carbonate solution of equal concentration.

[0106] Comparative Example 4

[0107] This comparative example provides a method for deep extraction of vanadium from vanadium-containing steel slag. The method is the same as Example 3 except that the ammonium bicarbonate solution in step (1) is replaced by a sodium hydroxide solution of equal concentration.

[0108] Testing method: Wash, dry and weigh the vanadium extraction tailings; use an inductively coupled plasma emission spectrometer to detect the vanadium content in the vanadium extraction tailings obtained in step (2) and calculate the vanadium leaching rate; and use this method to detect the impurity content and vanadium content in the vanadium-containing liquid.

[0109] The test results of the above embodiments and comparative examples are shown in Table 1.

[0110] Table 1

[0111]

[0112]

[0113] From Table 1, we can see the following points:

[0114] (1) It can be seen from Examples 1 to 7 that the method for deep extraction of vanadium from vanadium-containing steel slag provided by the present invention utilizes advanced oxidation in conjunction with mechanochemical activation to enhance vanadium leaching, the vanadium leaching rate is more than 83%, the vanadium content in the vanadium extraction tailings is within 0.5wt%, preferably within 0.3wt%, and the calcium content in the vanadium extraction solution is less than 54mg / L;

[0115] (2) In Example 8, except that the concentration of the ammonium bicarbonate solution is lower, the other conditions are exactly the same as those in Example 3, but the conversion rate is significantly lower than that in Examples 1 to 7. It can be seen that when the concentration of the ammonium bicarbonate solution is too low, the reaction will be insufficient and the vanadium in the vanadium-containing steel slag cannot be efficiently extracted. In Example 9, except that the concentration of the ammonium bicarbonate solution is higher, the other conditions are exactly the same as those in Example 3, but the conversion rate is significantly lower than that in Examples 1 to 7. It can be seen that when the concentration of the ammonium bicarbonate solution is too high, the viscosity of the solution will increase, affecting the diffusion of ions and the progress of the reaction, resulting in a decrease in the reaction rate. In Example 10, except that the oxygen content in the ammonium bicarbonate solution is too low, the reaction rate is significantly lower than that in Examples 1 to 7. The other conditions are exactly the same as those in Example 3, but the conversion rate is significantly lower than that in Examples 1 to 7. It can be seen that too low an oxygen content will lead to incomplete oxidation reaction, so that the valuable metal vanadium in the material cannot be fully converted into a soluble state, thereby reducing the leaching rate; in Example 11, except that the oxygen content in the ammonium bicarbonate solution is too high, the other conditions are exactly the same as those in Example 3, but the conversion rate is significantly lower than that in Examples 1 to 7. It can be seen that when the oxygen content is too high, a large number of bubbles will be formed at the gas-liquid interface, resulting in an increase in the gas-liquid mass transfer resistance, and the dissolution and diffusion rate of oxygen in the solution will be slowed down, so that the amount of oxygen actually participating in the reaction is reduced, affecting the oxidation effect.

[0116] (3) In Example 12, except that the liquid-to-solid ratio is too high, the other conditions are exactly the same as those in Example 3, but the conversion rate is significantly lower than that in Examples 1 to 7. It can be seen that when the liquid-to-solid ratio is too large, the concentration of the leaching agent in the solution is relatively low, which slows down the leaching reaction rate; in Example 13, except that the liquid-to-solid ratio is too low, the other conditions are exactly the same as those in Example 3, but the conversion rate is significantly lower than that in Examples 1 to 7. It can be seen that a too low liquid-to-solid ratio will lead to insufficient mass transfer driving force, which will slow down the diffusion rate of the leaching agent to the surface of the solid particles, and at the same time, the diffusion of the reaction product from the solid surface to the main body of the solution is also restricted, thereby reducing the leaching reaction rate; in Example 14, except that the ball-to-material ratio is too high, the other conditions are exactly the same as those in Example 3, but the conversion rate is significantly lower than that in Examples 1 to 7. It can be seen that a too large ball-to-material ratio will lead to excessive collision and friction between the ball and the material, resulting in excessive grinding of the material, which is prone to agglomeration and affects subsequent leaching. During the process, the leaching agent and the material are effectively in contact, which reduces the leaching efficiency; in Example 15, except that the ball-to-material ratio is too low, the other conditions are exactly the same as those in Example 3, but the conversion rate is significantly lower than that in Examples 1 to 7. It can be seen that the ball-to-material ratio is too low, the material cannot be fully ground and refined, the target components inside it are difficult to be fully exposed, and the contact area between the leaching agent and the material is limited, making it difficult to fully carry out the leaching reaction, resulting in a reduced leaching rate of the target components; in Example 16, except that the ball mill speed is too high, the other conditions are exactly the same as those in Example 3, but the conversion rate is significantly lower than that in Examples 1 to 7. It can be seen that too fast a speed will also cause the material to be over-ground and produce agglomeration; in Example 17, except that the ball mill speed is too low, the other conditions are exactly the same as those in Example 3, but the conversion rate is significantly lower than that in Examples 1 to 7. It can be seen that too low a speed will reduce the mass transfer efficiency, resulting in insufficient contact between the material and the leaching agent, and incomplete leaching reaction.

[0117] (4) In Example 18, only one type of grinding ball is used for mechanical ball milling activation. Compared with Example 3, the vanadium leaching rate is significantly reduced. This shows that the present invention preferably uses a combination of grinding balls with several diameters to significantly improve the effect of mechanical ball milling activation.

[0118] (5) In Comparative Example 1, except that the oxygen-containing microbubble ammonium bicarbonate solution was replaced with an ammonium bicarbonate solution of equal concentration, the other conditions were exactly the same as those in Example 3, but the conversion rate was significantly lower than that in Example 3, indicating that the present invention uses a micro-nano bubble generator to prepare oxygen-containing 2 Microbubble ammonium bicarbonate solution can effectively enhance the conversion of insoluble low-valent vanadium into soluble high-valent vanadium in vanadium-containing steel slag, which is beneficial to the leaching of vanadium.

[0119] (6) In Comparative Example 2, except for the absence of mechanochemical activation, the other conditions are exactly the same as those of Example 3, but the conversion rate is significantly lower than that of Example 3. It can be seen that mechanochemical activation can effectively destroy the calcium silicate and calcium ferrite phases of solid-dissolved vanadium, expose the vanadium, and effectively improve the conversion rate of vanadium. At the same time, it can also effectively reduce the particle size, increase the specific surface area, reduce the reaction activation energy, and promote the leaching of vanadium.

[0120] (7) Comparative Example 3 uses sodium carbonate instead of ammonium bicarbonate to extract vanadium from vanadium-containing steel slag. Other conditions are exactly the same as those in Example 3, but the conversion rate is significantly lower than that in Example 3. When sodium carbonate reacts with vanadium compounds in vanadium-containing steel slag, the leaching of vanadium may be incomplete or some intermediate products that are not conducive to subsequent treatment may be generated due to problems such as excessively violent reaction or solubility of the generated products. For example, sodium vanadate precipitate may be generated, covering the surface of the steel slag particles, hindering the further progress of the reaction and reducing the leaching rate of vanadium;

[0121] (8) Comparative Example 4 uses sodium hydroxide instead of ammonium bicarbonate to extract vanadium from vanadium-containing steel slag. Other conditions are exactly the same as those of Example 3. Although a leaching rate similar to that of Example 3 can be achieved, sodium hydroxide has the following problems: first, the cost is relatively high, which reduces production efficiency; second, it is highly corrosive and has high requirements on the material of the leaching equipment; third, the leaching selectivity is relatively poor, and the subsequent separation and purification process is complicated.

[0122] The present invention illustrates the detailed features of the present invention through the above embodiments, but the present invention is not limited to the above detailed features, that is, it does not mean that the present invention must rely on the above detailed features to be implemented. Those skilled in the art should understand that any improvement to the present invention, equivalent replacement of the technical features selected by the present invention, addition of auxiliary technical features, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for deep extraction of vanadium from vanadium-containing steel slag, characterized in that: The method comprises the following steps: The vanadium-containing steel slag and the oxygen-containing microbubble ammonium bicarbonate solution are mixed and activated by mechanochemical ball milling to carry out a leaching reaction to obtain a vanadium extraction solution.

2. The method according to claim 1, characterized in that The oxygen content of the oxygen-containing microbubble ammonium bicarbonate solution is 1 to 30 v%, preferably 10 to 25 v%; Preferably, the diameter of the oxygen microbubbles in the ammonium bicarbonate solution containing oxygen microbubbles is ≤50 μm, preferably ≤1 μm.

3. The method according to claim 1 or 2, characterized in that: The concentration of ammonium bicarbonate in the oxygen-containing microbubble ammonium bicarbonate solution is 25 to 60 wt %; Preferably, the preparation of the oxygen-containing microbubble ammonium bicarbonate solution comprises: preparing using a micro-nano bubble generator to obtain a freshly prepared oxygen-containing microbubble ammonium bicarbonate solution; Preferably, the prepared oxygen-containing microbubble ammonium bicarbonate solution is placed for less than or equal to 5 minutes before being transferred to the leaching reaction; Preferably, the preparation of the oxygen-containing microbubble ammonium bicarbonate solution comprises: introducing oxygen into the ammonium bicarbonate solution using a micro-nano bubble generator.

4. The method according to claims 1 to 3, characterized in that: The liquid-to-solid ratio of the oxygen-containing microbubble ammonium bicarbonate solution to the vanadium-containing steel slag is (2-10): 1 mL / g.

5. The method according to claims 1 to 4, characterized in that: The particle size of the vanadium-containing steel slag is 38-150 μm.

6. The method according to any one of claims 1 to 5, characterized in that: The mass fraction of vanadium in the vanadium-containing steel slag as vanadium pentoxide is 1 to 5 wt%; Preferably, the mass fraction of calcium in the vanadium-containing steel slag calculated as calcium oxide is 20 to 50 wt%.

7. The method according to any one of claims 1 to 6, characterized in that: The ball-to-material ratio of the mechanochemical ball milling activation is (3-30):1; Preferably, the diameter of the grinding balls activated by mechanochemical ball milling is 10-15 mm, accounting for 22-28%, 5-8 mm, accounting for 54-64%, and 1-3 mm, accounting for 14-18%.

8. The method according to any one of claims 1 to 7, characterized in that: The ball milling speed of the mechanochemical ball milling activation is 100 to 600 rpm; Preferably, the mechanochemical ball milling activation time is 30 to 120 minutes.

9. The method according to any one of claims 1 to 8, characterized in that: The leaching reaction temperature is 30-60°C; Preferably, the pH of the leaching reaction is 7-9.

10. The method according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: (1) introducing oxygen into an ammonium bicarbonate solution by using a micro-nano bubble generator to obtain a freshly prepared oxygen-containing micro-bubble ammonium bicarbonate solution; wherein the oxygen content is 1 to 30% by volume, the diameter of the oxygen micro-bubbles is ≤50 μm, and the concentration of ammonium bicarbonate is 25 to 60% by weight; (2) After the prepared oxygen-containing microbubble ammonium bicarbonate solution is placed for a period of less than or equal to 5 minutes, the prepared oxygen-containing microbubble ammonium bicarbonate solution and vanadium-containing steel slag with a particle size of 38 to 150 μm are immediately mixed at a liquid-to-solid ratio of (2 to 10):1, and the mixture is activated by mechanochemical ball milling at a temperature of 30 to 60° C., a pH of 7 to 9, and a ball milling speed of 100 to 600 rpm to carry out a leaching reaction for 30 to 120 minutes. The ball-to-material ratio is (3 to 30):1, and the diameters of the grinding balls are 10 to 15 mm, accounting for 22 to 28%, 5 to 8 mm, accounting for 54 to 64%, and 1 to 3 mm, accounting for 14 to 18%. After the leaching reaction, the materials are subjected to solid-liquid separation to obtain vanadium extraction liquid and vanadium extraction tailings.

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