Method for efficiently separating scandium from tungsten slag and application

Abstract

The invention provides a method for efficiently separating scandium from tungsten slag and application, and relates to the technical field of waste resourceful treatment. Specifically, dispersion liquid containing tungsten slag, an acid reagent, a reducing agent and organic reagents (an extracting agent, a modifying agent and sulfonated kerosene) is prepared, reaction is carried out in an ultrasonic state, then solid-liquid separation is carried out, and acid leaching slag and a liquid phase containing an organic phase and a water phase are obtained; carrying out washing and reverse extraction on the organic phase, and then separating in a water phase to obtain a scandium hydroxide crude product; preparing the scandium hydroxide crude product into a solution, removing impurities through ion exchange resin, and adding oxalic acid for reaction to obtain scandium oxalate precipitate; and calcining to obtain scandium oxide. The method provided by the invention can effectively solve the defect of long process of extracting scandium from tungsten slag and the technical problem that scandium and iron are difficult to separate, and the obtained scandium oxide product has high purity, good scandium recovery rate and good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of waste resource treatment, and more specifically, to a method for efficiently separating scandium from tungsten slag and its application. Background Art

[0002] With the rapid development of China's economy, the demand for tungsten concentrate has been increasing continuously. China has become a major consumer of tungsten concentrate. In 2022, the total consumption of tungsten concentrate in China was approximately 63,000 tons, and the annual output of tungsten slag was about 20,000 tons. After tungsten concentrate is mined and crushed, it needs to go through a series of complex technological processes such as beneficiation, chemical treatment, and calcination to obtain metal tungsten products. During this process, tens of thousands of tons of tungsten slag are inevitably accumulated. The main components of tungsten slag include but are not limited to valuable metals such as tungsten, iron, copper, nickel, silver, scandium, tin, tantalum, and niobium. Recycling various metals in tungsten slag has important practical significance and economic value.

[0003] Scandium has a wide range of applications in many cutting-edge fields such as aerospace, military industry, electronics industry, nuclear technology, and superconducting technology, such as structural materials for rockets and aircraft, aerospace materials, nuclear materials, high-temperature superconductors, laser crystals, coatings, scandium-sodium lamps, etc. Although China is one of the countries with the richest scandium resources in the world, in recent years, the demand for scandium has been increasing continuously, and the price has also been rising. If scandium can be effectively recovered from tungsten slag, it will be of great significance for alleviating the shortage of scandium resources in China, improving resource utilization rate, and promoting the development of related industries.

[0004] Currently, the recovery of scandium from tungsten slag mainly involves acid leaching processes, and the acids used can be hydrochloric acid, sulfuric acid, nitric acid, etc. For example, CN201510878054.2 discloses a method for treating tungsten slag. First, the tungsten slag is wet ball-milled into fine powder slurry, and then the washed slag after water washing is subjected to five-stage countercurrent continuous acid leaching to recover silver and scandium from the leachate. Another example is CN201810969870.8, which discloses a method for separating and recovering valuable metals iron, manganese, and scandium from tungsten slag. First, tungsten slag is leached with sulfuric acid, and valuable metals such as iron, manganese, and scandium exist in the leachate in the form of their respective ions. Then, P204 and sulfonated kerosene are used as the organic phase to simultaneously extract iron ions, manganese ions, and scandium ions, and the extraction rates are 97%, 95%, and 99% respectively. Then, different stripping agents are used for sequential selective stripping to separate and recover manganese, iron, and scandium in the loaded organic phase. Another example is CN201910184860.8, which discloses a method for extracting scandium from refractory high-silicon scandium-rich tungsten slag. An acid solution added with EDTA is used as the leaching agent to leach the high-silicon scandium-rich tungsten slag. After leaching, solid-liquid separation is carried out to obtain the leached residue and the scandium-containing leachate; by adding EDTA to promote the aggregation and precipitation of silica gel, the adsorption of silica gel on scandium is reduced, significantly reducing the filtration time while significantly increasing the leaching rate of scandium.

[0005] In the acid leaching solution of tungsten slag, there are scandium, iron and complex metal ions. For the separation of similar ions (such as the separation of iron ions and scandium ions), a reduction separation method has been proposed in some studies for the process of extracting scandium oxide from tungsten slag waste. The specific process includes the following steps: washing tungsten slag with water to remove alkali, sulfuric acid leaching (hot acid dilution), reducing iron ions with iron filings, extracting with primary amine N1923, precipitating with ammonia water, dissolving with hydrochloric acid, precipitating with oxalic acid, and calcining to obtain scandium oxide. The purity of the scandium oxide product obtained by this process is 90%, and the recovery rate is 82%. This process can achieve the full recovery of scandium in tungsten slag, but there are still some defects: such as long reaction time, high temperature, long process. Traditional acid leaching requires high temperature (>120°C) or long reaction time (3 - 5h), and the similar physical and chemical properties of Fe3+ and Sc 3 + lead to technical problems such as difficult separation.

[0006] In view of this, the present invention is specifically proposed. Summary of the Invention

[0007] The first object of the present invention is to provide a method for efficiently separating scandium from tungsten slag, which is used to solve the technical problems such as long process flow, serious iron interference, and high energy consumption in the current tungsten slag treatment process when obtaining scandium or scandium products. The method of the present invention is efficient, concise, environmentally friendly, has a short process and low cost, and has important practical significance and broad application prospects.

[0008] The second object of the present invention is to provide a method for resource treatment of tungsten slag.

[0009] In order to achieve the above objects of the present invention, the following technical solutions are specifically adopted:

[0010] A method for efficiently separating scandium from tungsten slag includes the following steps:

[0011] (1) Prepare a dispersion liquid containing tungsten slag, acid reagent, reducing agent and organic reagent, and the organic reagent includes extractant, modifier and sulfonated kerosene;

[0012] (2) React the dispersion liquid under ultrasonic state. After the reaction is completed, perform solid-liquid separation to obtain acid leaching residue and a liquid phase containing organic phase and aqueous phase;

[0013] (3) Wash and back-extract the organic phase, and then separate crude scandium hydroxide from the aqueous phase;

[0014] (4) Prepare the crude scandium hydroxide into a solution. After removing impurities through ion exchange resin, add oxalic acid to the solution for reaction to obtain scandium oxalate precipitate;

[0015] (5) Calcinate the scandium oxalate precipitate to obtain high-purity scandium oxide.

[0016] A method for the resource treatment of tungsten slag, including the method for efficiently separating scandium from tungsten slag.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] (1) The present invention adopts ultrasonic enhanced pulp extraction technology, directly mixes tungsten slag, acid solution and extractant, and through the ultrasonic cavitation effect, can effectively destroy the structure of tungsten slag, increase the contact area between the acid solution and tungsten slag, thereby accelerating the leaching process of scandium and shortening the leaching time, and improving the leaching rate. At the same time, the present invention also adds a reducing agent to reduce ferric iron in the solution to ferrous iron, avoiding the competition of ferric iron with scandium ions for the extractant, reducing the possibility of impurity iron entering the extractant, improving the selectivity and purity of scandium in the subsequent extraction process, and effectively reducing the subsequent impurity removal process. Further, the present invention separates after ultrasonic enhanced acid leaching and extraction, effectively reducing the operation process; the present invention also adopts the processes of impurity removal by ion exchange resin and scandium precipitation with oxalic acid, significantly improving the purity (≥99.5%) of scandium oxide products and the total recovery rate of scandium (≥90%).

[0019] (2) The process flow of the present invention can achieve efficient leaching of scandium in tungsten slag in a relatively short time, greatly improving the specific treatment efficiency of tungsten slag for scandium, and at the same time reducing the production cost. Through the ultrasonic cavitation effect, the leaching time of scandium is shortened from about 5 h in the conventional method to 1 h, and the leaching rate of scandium is increased from 85% to 95%.

[0020] (3) Adding a reducing agent in the present invention effectively reduces the interference of impurity iron on scandium extraction, improves the extraction selectivity and purity of scandium, and significantly improves the purity of the final scandium oxide product; through reduction, the leaching rate of Fe < 5%, and the Sc / Fe ratio in the loaded organic phase of the liquid phase > 100. Description of the Drawings

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required to be used in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 A process flow chart for efficiently separating scandium from tungsten slag is provided. Specific Embodiments

[0023] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present invention. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0024] The first aspect of the present invention is to provide a method for efficiently separating scandium from tungsten slag, which mainly includes the following steps (1) to (5), as Figure 1 shown, a simple schematic of the following steps of the present invention is given.

[0025] (1) Prepare a dispersion liquid containing tungsten slag, acid reagent, reducing agent and organic reagent, and the organic reagent includes extractant, modifier and sulfonated kerosene.

[0026] As a preferred embodiment, the tungsten slag includes the following components by mass percentage: iron oxide 28 wt.% to 40 wt.%, silicon oxide 20 wt.% to 30 wt.%, aluminum oxide ≤ 10 wt.%, calcium oxide ≤ 8 wt.%, titanium oxide ≤ 5 wt.%, scandium oxide ≤ 1 wt.%. It should be noted that other inevitable trace components such as manganese, tungsten, copper, nickel, tantalum, niobium, magnesium, etc. are also contained in the tungsten slag, which is restricted by the tungsten concentrate and its smelting process adopted, and there is great variability or volatility.

[0027] As a preferred embodiment, the particle size of the tungsten slag is 160 mesh to 300 mesh; in some more preferred embodiments, the tungsten slag is obtained by grinding, and the grinding is carried out by means including but not limited to ball milling, vibration milling, etc. By using the tungsten slag with a specific particle size and uniformity, it is helpful for the full progress of ultrasonic enhanced acid leaching in step (2).

[0028] As a preferred embodiment, the acid reagent includes hydrochloric acid; it should be understood that when other common acids are used, such as sulfuric acid may produce precipitates with some metal ions, nitric acid has certain safety risks, phosphoric acid will cause water pollution, etc., while acids such as acetic acid and formic acid are far inferior to hydrochloric acid in terms of cost. In the present invention, a lower concentration of hydrochloric acid is selected as the leaching acid. Combining with the subsequent extraction process, the complexation stability of scandium ions with the extractant in the hydrochloric acid system is better, which is beneficial to improving the recovery rate of scandium.

[0029] As a more preferred embodiment, the hydrochloric acid used is an aqueous hydrochloric acid solution with a concentration of 1 mol / L to 3 mol / L. It should be noted that in the present invention, low-concentration hydrochloric acid is used as the leaching acid, which reduces the corrosion of equipment during the high-concentration acid leaching process in the existing process, extends the service life of the equipment, and at the same time improves the recovery rate of scandium, having better economy and environmental protection.

[0030] As a preferred embodiment, the reducing agent includes at least one of ascorbic acid, sulfite, citric acid, tartaric acid or thiosulfate. Among them, the sulfite includes, but is not limited to, sodium sulfite or potassium sulfite, etc., and the thiosulfate includes, but is not limited to, sodium thiosulfate or potassium thiosulfate, etc.; in some more preferred embodiments, the reducing agent is ascorbic acid.

[0031] As a preferred embodiment, the extractant includes at least one of P204, P507, Cyanex272 or Cyanex923.

[0032] As a preferred embodiment, the modifier includes at least one of TBP, sec-octanol or isooctanol.

[0033] As a preferred embodiment, the organic reagent includes 10 vt.% to 40 vt.% of extractant, 10 vt.% to 40 vt.% of modifier and 20 vt.% to 80 vt.% of sulfonated kerosene by volume percentage; in an alternative embodiment, those skilled in the art can adaptively adjust the dosages of the extractant and the modifier according to the specific composition of the tungsten slag and the types of the extractant and the modifier selected accordingly, and further use the sulfonated kerosene to fill the remaining amount.

[0034] As a preferred embodiment, the solid-liquid ratio of the tungsten slag to the acid reagent is 1:3 to 6 (unit: g / mL).

[0035] As a preferred embodiment, based on the iron content in the tungsten slag, the molar ratio of the tungsten slag to the reducing agent is 1:1 to 2.

[0036] As a preferred embodiment, the volume ratio of the acid reagent to the organic reagent is 5:1 to 1:5; in an alternative embodiment, those skilled in the art can adaptively adjust the total dosage of the organic reagent according to the specific composition of the tungsten slag and the types of the extractant and the modifier selected accordingly.

[0037] (2) React the dispersion under ultrasonic conditions, and after the reaction is completed, perform solid-liquid separation to obtain acid leaching residue and a liquid phase containing an organic phase and an aqueous phase.

[0038] In this step, ultrasonic-assisted leaching and extraction are carried out. Through the ultrasonic cavitation effect, good acid leaching effect and acid leaching efficiency are achieved, and at the same time, the interference of iron during the extraction of scandium is realized. Specifically: The present invention utilizes the propagation of ultrasonic waves in the reaction dispersion liquid. Due to the compression and rarefaction of the liquid medium, tiny bubbles or cavities will be formed in the liquid; these bubbles or cavities grow in the negative pressure phase of the ultrasonic wave and quickly close in the positive pressure phase, generating a local high-temperature and high-pressure environment, accompanied by strong microjets and shock waves, that is, the ultrasonic cavitation effect is formed; in the present invention, the ultrasonic cavitation effect is used to accelerate the penetration of the acid solution into the tungsten slag, accelerate the mass transfer of scandium in the tungsten slag from the solid phase to the liquid phase, and effectively shorten the leaching time to within 1 h. In addition, ultrasound can also promote the dispersion of the extractant, enabling Sc 3+ to selectively complex and enter the organic phase, and at the same time, the added reducing agent can reduce Fe 3+ to Fe 2+ , and Fe 2+ is not easily extracted by the extractant of the present invention under high acidity conditions, avoiding the co-extraction of subsequent iron impurities and scandium ions, and effectively reducing the complexity of impurity removal.

[0039] As a preferred embodiment, the power of the ultrasonic state is 200 W to 800 W, the frequency of the ultrasonic state is 20 kHz to 60 kHz, and the reaction time under the ultrasonic state is 30 min to 60 min. As a more preferred embodiment, the power of the ultrasonic state is 200 W to 500 W, and the frequency of the ultrasonic state is 20 kHz to 40 kHz.

[0040] As an alternative embodiment, the power of the ultrasonic state includes but is not limited to any one of 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800 (W) or any numerical range composed of any two of them; the frequency of the ultrasonic state includes but is not limited to any one of 20, 25, 30, 35, 40, 45, 50, 55, 60 (kHz) or any numerical range composed of any two of them; the reaction time under the ultrasonic state includes but is not limited to any one of 30, 35, 40, 45, 50, 55, 60 (min) or any numerical range composed of any two of them.

[0041] As a preferred embodiment, the solid-liquid separation includes but is not limited to decantation, filtration, centrifugation, filter mesh or membrane separation methods, etc.

[0042] As a more preferred embodiment, the solid-liquid separation is carried out by centrifugation; the rotation speed of the centrifugation is 2000 rpm to 5000 rpm, the time of the centrifugation is 10 min to 30 min, and the temperature of the centrifugation is not limited, and it is usually carried out at room temperature.

[0043] As a preferred embodiment, those skilled in the art can chemically treat the acid leaching residue to recover the tantalum and niobium elements enriched in the acid leaching residue.

[0044] (3) Wash and strip the organic phase, and then separate the crude scandium hydroxide from the aqueous phase.

[0045] As a preferred embodiment, the washing includes the following steps: adding an acid solution to the liquid phase to wash away the impurity ions in the organic phase; at the same time, since the reagent introduced by the washing is aqueous, the acid solution carrying the impurity ions will directly enter the aqueous phase; it can be understood that the main purpose of the washing here is for the organic phase, but the liquid separation operation of the liquid phase is not involved before the washing process.

[0046] As a more preferred embodiment, the acid solution includes at least one of a sulfuric acid solution or a hydrochloric acid solution with a concentration of 0.1 mol / L to 1 mol / L; the dosage of the acid solution is adaptively adjusted according to the washing effect of the organic phase, and it is not strictly limited in the present invention.

[0047] As a preferred embodiment, the stripping includes the following steps: adding an alkali solution to the washed liquid phase to cause the scandium ions in the organic phase to react to form scandium hydroxide precipitate and enter the bottom of the aqueous phase; thus, it is possible to obtain the crude scandium hydroxide based on the separation of the aqueous phase in subsequent operations.

[0048] As a more preferred embodiment, the alkali solution includes at least one of a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 1 mol / L to 5 mol / L; the dosage of the alkali solution is until no more precipitate precipitates in the organic phase, and it is not strictly limited in the present invention.

[0049] As a preferred embodiment, the separation of the aqueous phase similarly includes but is not limited to decantation, filtration, centrifugation, filter mesh or membrane separation methods, etc.

[0050] As a preferred embodiment, for the aqueous phase after the separation, as Figure 1 shown, it is called the acid leaching solution, which is enriched with iron elements. Those skilled in the art can obtain resource products such as iron through additional recovery and purification processes.

[0051] (4) Prepare the crude scandium hydroxide into a solution, remove impurities through an ion exchange resin, and then add oxalic acid to the solution for reaction to obtain scandium oxalate precipitate.

[0052] As a preferred embodiment, in the solution of crude scandium hydroxide, the solvent is hydrochloric acid solution; the concentration of the hydrochloric acid solution is 1 mol / L to 5 mol / L, and the solid-liquid ratio of the crude scandium hydroxide to the hydrochloric acid solution is 1:1 to 5 (g / mL).

[0053] As a preferred embodiment, the ion exchange resin includes at least one of D851 or D860 to achieve deep impurity removal, especially for the removal of similar impurities such as Zr.

[0054] As a preferred embodiment, after impurity removal by the ion exchange resin, first adjust the pH of the solution to 1 to 3 with hydrochloric acid, then heat it to 80°C to 95°C, and then add the oxalic acid and carry out a precipitation reaction to obtain the scandium oxalate precipitate. In this preferred embodiment, the precipitation reaction conditions of scandium oxalate are further refined to improve the reaction efficiency while reducing the reaction cost, and at the same time improve the precipitation recovery rate of scandium. In some more preferred embodiments, the addition amount of the oxalic acid should be judged based on the disappearance of precipitation in the solution, or based on the reaction equation: 2Sc 3+ + 3H2C2O4 = Sc2(C2O4)3 + 6H+, and the amount of oxalic acid introduced should be slightly higher than 3 / 2 of the molar amount of scandium ions in the solution.

[0055] (5) Calcinate the scandium oxalate precipitate to obtain high-purity scandium oxide.

[0056] In this step, based on the reaction equation: 2Sc2(C2O4)3 + 3O2 = 2Sc2O3 + 12CO2, the scandium oxalate obtained through the previous steps is calcined to obtain the scandium oxide product.

[0057] As a preferred embodiment, the calcination temperature is 550°C to 750°C, and the calcination time is 1.5 h to 3 h.

[0058] As a preferred embodiment, the purity of the high-purity scandium oxide ≥ 99.5%.

[0059] The second aspect of the present invention is to provide a method for resource treatment of tungsten slag, including the method for efficiently separating scandium from tungsten slag as described in the first aspect. It can be understood that in the method for resource treatment of tungsten slag described in this aspect, it can be based on the method for efficiently separating scandium from tungsten slag with additional pre- or post-treatment processes, or even additional operation steps are set in the method for efficiently separating scandium from tungsten slag; on the premise of including the complete method for efficiently separating scandium from tungsten slag, any treatment process for the tungsten slag can be used as an embodiment of this aspect.

[0060] Example 1

[0061] The tungsten slag used in this embodiment has the composition shown in Table 1 below.

[0062] Table 1

[0063] Component <![CDATA[Sc2O3]]> <![CDATA[Fe2O3]]> <![CDATA[SiO2]]> <![CDATA[Al2O3]]> CaO <![CDATA[TiO2]]> Others Content (%) 0.085 32.7 25.4 8.6 4.2 1.8 Balance

[0064] S1 Pretreatment: Put 1000 g of tungsten slag into a ball mill and grind it to 200 mesh to obtain the finely ground tungsten slag powder.

[0065] S2 Pulp preparation: Mix 500 g of the finely ground tungsten slag powder with 2000 mL of hydrochloric acid solution with a concentration of 2 mol / L, add a reducing agent (ascorbic acid), and the addition amount is 1.5 times the molar amount of the theoretical Fe content in the slag. Add an organic phase, and the volume ratio of the organic phase to hydrochloric acid is 3:2; the organic phase consists of P204 extractant with a volume fraction of 25% (vol / vol), TBP modifier with a volume fraction of 15%, and sulfonated kerosene with a volume fraction of 60%. Stir the mixture thoroughly to form a uniform pulp.

[0066] S3 Ultrasonic enhanced leaching: Pour the pulp into an ultrasonic reactor, turn on the ultrasonic equipment, set the ultrasonic power to 350 W, the frequency to 30 kHz, and the reaction time to 45 min. During the ultrasonic process, it is observed that tiny bubbles appear in the pulp accompanied by slight vibration and noise, which is the manifestation of the ultrasonic cavitation effect and helps to accelerate the penetration of the acid solution and the mass transfer of scandium from the solid phase to the liquid phase.

[0067] S4 Centrifugal separation of the loaded organic phase: After the ultrasonic reaction is completed, pour the pulp into a centrifuge tube and perform solid-liquid separation with a centrifuge. The centrifugal speed is 4000 r / min and the centrifugal time is 10 min. After separation, the liquid phase of the loaded organic phase and the acid leaching solution, as well as the solid phase of the acid leaching residue, are obtained. Transfer the liquid phase of the loaded organic phase and the aqueous phase to another container for separation. The loaded organic phase is washed with sulfuric acid solution with a concentration of 0.5 mol / L, and the phase ratio is 4:1 to wash away some impurity ions. The washed loaded organic phase is back-extracted with sodium hydroxide solution with a concentration of 3 mol / L, and the phase ratio is 3:1. Sc in the organic phase 3+ is converted into scandium hydroxide precipitate and enters the bottom of the aqueous phase. After filtering the precipitate, crude scandium hydroxide is obtained.

[0068] Preparation of high-purity scandium oxide: After washing the crude scandium hydroxide precipitate with an appropriate amount of water, it is acid-dissolved with a hydrochloric acid solution with a concentration of 3 mol / L, and the solid-liquid ratio is 1:3 to obtain a scandium salt solution. The scandium salt solution is transferred to an ion exchange column, and D851 resin is used to deeply remove similar impurities such as Zr to obtain a purified solution. After adjusting the pH of the purified solution to 2 with hydrochloric acid, oxalic acid is added, and precipitation is carried out under heating conditions until no more precipitation occurs, then the addition of oxalic acid is stopped, and the scandium oxalate precipitate is obtained by filtration. The scandium oxalate precipitate is placed in a muffle furnace and calcined at 650 °C for 2 h to obtain the scandium oxide product of this example.

[0069] Example 2

[0070] It is basically the same as Example 1, except that:

[0071] In step S2, the reducing agent is replaced with an equimolar amount of sodium nitrite; the extractant is replaced with Cyanex272; the modifier is replaced with isooctanol.

[0072] Example 3

[0073] It is basically the same as Example 1, except that:

[0074] S2 Pulp preparation: 500 g of finely ground tungsten slag powder is mixed with 2500 mL of hydrochloric acid solution with a concentration of 2.5 mol / L, a reducing agent (ascorbic acid) is added, and the addition amount is 2 times the molar amount of the theoretical Fe content in the slag. An organic phase is added, and the volume ratio of the organic phase to hydrochloric acid is 1:1; the composition of the organic phase remains the same as in Example 1. The mixture is stirred well to form a uniform pulp.

[0075] Example 4

[0076] It is basically the same as Example 1, except that:

[0077] In step S3, the ultrasonic conditions are replaced with: the ultrasonic power is set to 600 W, the frequency is set to 40 kHz, and the reaction time is 30 min.

[0078] Example 5

[0079] It is basically the same as Example 1, except that:

[0080] In step S3, the ultrasonic conditions are replaced with: the ultrasonic power is set to 200 W, the frequency is set to 20 kHz, and the reaction time is 60 min.

[0081] The purity of the scandium oxide products obtained in each example was detected, and the recovery rate of scandium was calculated based on the scandium content in the tungsten slag. The results are shown in Table 2 below. It can be seen from Table 2 that the scandium oxide obtained by the separation method of the present invention has extremely high purity and a good recovery rate for scandium.

[0082] Table 2

[0083]

[0084]

[0085] Although the present invention has been illustrated and described with reference to specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Those of ordinary skill in the art should understand that without departing from the spirit and scope of the present invention, the technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A method for efficiently separating scandium from tungsten slag, characterized in that, It includes the following steps: (1) Prepare a dispersion liquid containing tungsten slag, acid reagent, reducing agent and organic reagent, where the organic reagent includes extractant, modifier and sulfonated kerosene; (2) React the dispersion liquid under ultrasonic condition, and after the reaction ends, perform solid-liquid separation to obtain acid leaching residue and a liquid phase containing organic phase and aqueous phase; (3) Wash and back-extract the organic phase, and then separate crude scandium hydroxide from the aqueous phase; (4) Prepare the crude scandium hydroxide into a solution, after impurity removal by ion exchange resin, add oxalic acid to the solution for reaction to obtain scandium oxalate precipitate; (5) Calcinate the scandium oxalate precipitate to obtain high-purity scandium oxide.

2. The method according to claim 1, wherein Step (1) includes at least one of the following features (a) to (e): (a) The particle size of the tungsten slag is 160 mesh to 300 mesh; (b) The acid reagent includes a hydrochloric acid solution with a concentration of 1 mol / L to 3 mol / L; (c) The reducing agent includes at least one of ascorbic acid, sulfite, citric acid, tartaric acid or thiosulfate; (d) The extractant includes at least one of P204, P507, Cyanex272 or Cyanex923; (e) The modifier includes at least one of TBP, sec-octanol or isooctanol.

3. The method according to claim 1, wherein Step (1) includes at least one of the following features (A) to (D): (A) The volume ratio of the extractant to the modifier is (1 to 4):(1 to 4); (B) The solid-liquid ratio of the tungsten slag to the acid reagent is 1:3 to 6, with the unit of g / mL; (C) The molar ratio of iron in the tungsten slag to the reducing agent is 1:1 to 2; (D) The volume ratio of the acid reagent to the organic reagent is 5:1 to 1:

5.

4. The method according to claim 1, characterized in that, The power of the ultrasonic condition is 200 W to 800 W, the frequency of the ultrasonic condition is 20 kHz to 60 kHz, and the reaction time under the ultrasonic condition is 30 min to 60 min.

5. The method according to claim 1, characterized in that, The washing includes the following steps: Add an acid solution to the liquid phase, and let the acid solution carrying impurity ions flow into the aqueous phase; Preferably, the acid solution includes at least one of a sulfuric acid solution or a hydrochloric acid solution with a concentration of 0.1 mol / L to 1 mol / L.

6. The method according to claim 1, characterized in that, The back-extraction includes the following steps: Add an alkali solution to the washed liquid phase, and let the scandium ions in the organic phase react to obtain scandium hydroxide and precipitate to the aqueous phase; Preferably, the alkali solution includes at least one of a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 1 mol / L to 5 mol / L.

7. The method according to claim 1, characterized in that, In step (4), in the solution of the crude scandium hydroxide, the solvent is a hydrochloric acid solution; Preferably, the concentration of the hydrochloric acid solution is 1 mol / L to 5 mol / L, and the solid-liquid ratio of the crude scandium hydroxide to the hydrochloric acid solution is 1:1 to 5, with the unit of g / mL.

8. The method according to claim 1, wherein In step (4), after impurity removal by ion exchange resin, first adjust the pH of the solution to 1 to 3 with hydrochloric acid, then heat to 80 °C to 95 °C, and then add the oxalic acid and perform a precipitation reaction to obtain the scandium oxalate precipitate.

9. The method according to claim 1, characterized in that, The calcination temperature is 550°C to 750°C, and the calcination time is 1.5 h to 3 h.

10. A resource treatment method for tungsten slag, characterized in that, It includes the method for efficiently separating scandium from tungsten slag according to any one of claims 1 to 9.

Images