Method for extracting and recovering scandium and copperas from scandium-containing solution without emulsification

Abstract

The invention discloses a method for extracting and recovering scandium and copperas from a scandium-containing solution without emulsification. The method comprises the following steps: (1) leaching scandium-containing waste residues by using titanium white waste acid to obtain a scandium-containing leachate; (2) a certain amount of iron powder is added into the scandium-containing leachate, after the iron powder reacts completely, the solution is put into a low-temperature constant-temperature tank to be crystallized, suction filtration is conducted after crystallization is completed, and iron-removed leachate and copperas are obtained; and (3) extracting the iron-removed leachate by using a P204-TBP extraction system to obtain a scandium-containing organic phase, wherein the scandium-containing organic phase is not emulsified in the process.

Description

Technical Field

[0001] The invention belongs to the field of solid waste resource recovery, and mainly relates to a method for recovering scandium and co-producing green vitriol from a scandium-containing solution by non-emulsification extraction. Background Art

[0002] Scandium is a rare element. It has high chemical activity, good electrical conductivity, and is soft and easy to cut. It is generally used as a trace additive in the preparation of high-tech products such as solid oxide fuel cells, high-performance aluminum-scandium alloy materials, high-radioactive isotope tracers, and laser crystal materials. It has irreplaceable application value in a series of modern high-tech fields such as new energy materials, modern information technology, and aerospace. The average abundance of scandium in the earth's crust is 3.6×10 -3 %, during the smelting process of these minerals, scandium will gradually be enriched in secondary resources such as smelting slag. At present, since there are no or very few independent deposits of scandium, scandium is mainly recovered from secondary resources containing scandium.

[0003] Normally, for scandium-containing materials, such as tungsten slag, chlorinated smoke, titanium tailings, etc., acid leaching treatment is used to make scandium enter the solution from the solid material, and then extraction-strip extraction is used to separate scandium from impurity elements and enrich them in the stripping solution, and then precipitation-calcination method is used to obtain scandium oxide products. For scandium-containing solutions such as sulfuric acid titanium dioxide waste acid, it is usually used to treat scandium-containing materials to obtain scandium-containing solutions, and then extraction-strip extraction-precipitation-calcination process is used to obtain scandium oxide products. Commonly used extractants in the extraction process include P204, P507, N1923, Cyanex923, Cyanex572 and other extractants. Among them, P204 is widely used in the extraction of scandium due to its high extraction rate and low price. However, since the obtained scandium-containing solution contains more impurities, especially Fe 3+ , which will not only produce emulsification during the extraction of P204, but also reduce the extraction rate of scandium.

[0004] Domestic scholars have done a lot of research on the recycling of scandium in secondary resources. Among them, patent CN201210106278.8 uses a step-by-step acid leaching method to leach high-iron bauxite. The first-step leaching crystallization obtains iron sulfate to achieve the purpose of iron removal. The second-step leaching extracts aluminum from the first-step leaching residue, and then uses an organic extract containing P507 to extract scandium, and uses an organic extract containing HDEHP to extract gallium. Patent CN201310131176.6 uses an organic phase containing N235 to extract iron from scandium-rich iron acid solution, and the extraction rate reaches more than 99.5%. Then, an organic phase containing P204 is used to extract scandium, and the extraction rate can reach more than 99%. The above studies all pre-de-ironize the leaching solution, and then extract the de-ironizing solution to extract scandium. It can be seen that de-ironization has a greater impact on extraction.

[0005] Based on the above, the present invention proposes a method for recovering scandium from a scandium-containing solution by emulsification-free extraction and co-production of green vitriol. The specific route is: using titanium dioxide waste acid to leach scandium-containing waste residue under certain conditions to obtain a scandium-containing leaching solution, adding iron powder to the scandium-containing leaching solution, and using the iron powder to remove Fe 3+ Converted to Fe 2+ , put it into a low-temperature thermostatic tank for crystallization to obtain green vitriol (FeSO4·7H2O), and then use the P204-TBP system to extract the iron-removed leaching solution under certain conditions to obtain a scandium-rich organic phase. This process uses industrial waste acid to leach industrial solid waste, realizing the utilization of secondary resources. At the same time, iron powder is used as a reducing agent to remove iron to avoid the formation of the third phase in subsequent extraction, and green vitriol is obtained. The operation is simple and economical, which provides a new solution to the emulsification phenomenon that occurs during the extraction of scandium by the P204-TBP system. Summary of the invention

[0006] Aiming at the problems of easy generation of a third phase in the P204-TBP extraction process, extraction of scandium from secondary scandium-containing resources, and treatment of industrial solid waste and wastewater from titanium dioxide, the present invention provides a method for extracting and recovering scandium from a scandium-containing solution without emulsification and producing green vitriol.

[0007] The method for recovering scandium from a scandium-containing solution by using a P204-TBP system without emulsification to produce green vitriol is described in the present invention. The scandium-containing waste residue, titanium dioxide waste acid and iron powder are used as raw materials. The process steps are as follows:

[0008] 1. Titanium dioxide waste acid leaching of scandium-containing waste slag

[0009] The scandium-containing waste slag finely ground to less than 150 μm is leached with titanium dioxide waste acid, and the liquid-solid ratio of the titanium dioxide waste acid to the scandium-containing waste slag is controlled to be 6 to 12; the leaching temperature is 25 to 80° C.; the leaching is performed for 30 to 90 minutes, and the leaching solution is obtained after filtration;

[0010] 2. Iron removal from leachate

[0011] The leaching solution obtained in step 1 is subjected to Fe 3+ Content test, according to mFe:mFe 3+ = 0.1 ~ 0.5 ratio of iron powder is added thereto for reaction, after the reaction is complete, placed in a low temperature thermostatic bath for crystallization treatment, the crystallization temperature is -10 ~ 10 ° C; after filtration, iron removal leaching solution and green vitriol are obtained.

[0012] 3. Extraction of Scandium by P204-TBP System

[0013] The iron removal leaching solution obtained in step 3 is extracted with a P204-TBP extraction system. The extraction conditions are as follows: A / O=1-10, the concentration of P204 is 10%-20%, the concentration of TBP is 5%-20%, and the temperature is 25-70°C.

[0014] Compared with the prior art, the present invention has the following advantages: (1) the process recovers scandium from the leachate obtained by leaching scandium-containing waste slag with titanium dioxide waste acid, thereby achieving full utilization of secondary resources, avoiding resource waste and reducing environmental pollution; (2) the process utilizes iron powder to remove iron from the leachate to avoid emulsification, saving the cost of iron removal and forming a usable green vitriol product; (3) the process of the present invention is simple, easy to operate, low in production cost, and has prospects for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is the process flow chart of the present invention Figure 2 This is the XRD diagram of the product after adding iron powder crystallization Figure 3 This is a diagram of the emulsification process during extraction in different cases Embodiment 1 (1) Using titanium dioxide waste acid to leach scandium-containing waste slag finely ground to less than 150 μm, controlling the liquid-solid ratio of titanium dioxide waste acid to scandium-containing waste slag to be 6; the leaching temperature is 25°C; leaching for 30 minutes, and obtaining the leachate after filtration; (2) The leaching solution obtained in step 1 is subjected to Fe 3+ Content test, according to mFe:mFe 3+ =0.25 ratio, iron powder was added thereto for reaction. After the reaction was complete, the mixture was placed in a low-temperature thermostatic bath for crystallization at a crystallization temperature of -10°C. After suction filtration, an iron removal leaching solution was obtained. DETAILED DESCRIPTION

[0015] The present invention is described in detail below in conjunction with the embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0016] The main chemical element contents (mass percentage) of the scandium-containing waste slag used in the following examples are 29.3% Fe, 2.57% Mn, 0.556% Ti, 0.616% Al, 4.77% Ca, and 0.017% Sc. XRD analysis results show that the main chemical element contents (g / L) of the titanium dioxide waste acid used are 46.43% Fe, 1.71% Mn, 2.65% Ti, 3.89% Ca, 2.95% Al, and 0.0051% Sc.

[0017] Embodiment 1

[0018] (1) using titanium dioxide waste acid to leach scandium-containing waste slag finely ground to less than 150 μm, controlling the liquid-solid ratio of titanium dioxide waste acid to scandium-containing waste slag to be 6; the leaching temperature is 25° C.; leaching for 30 minutes, and obtaining a leachate after suction filtration;

[0019] (2) The leaching solution obtained in step 1 is subjected to Fe 3+ Content test, according to mFe:mFe 3+ =0.25 ratio, iron powder was added thereto for reaction. After the reaction was complete, the mixture was placed in a low-temperature thermostatic bath for crystallization treatment at a crystallization temperature of -10°C. After suction filtration, an iron removal leaching solution was obtained.

[0020] (3) The iron removal leaching solution obtained in step 3 was extracted using a P204-TBP extraction system. The extraction conditions were 10% P204-5% TBP, A / O=1, and a temperature of 25° C. The extraction rate reached 98.9%.

[0021] Embodiment 2

[0022] (1) using titanium dioxide waste acid to leach scandium-containing waste slag finely ground to less than 150 μm, controlling the liquid-solid ratio of titanium dioxide waste acid to scandium-containing waste slag to be 8; the leaching temperature is 40° C.; leaching for 45 minutes, and obtaining a leachate after suction filtration;

[0023] (2) The leaching solution obtained in step 1 is subjected to Fe 3+ Content test, according to mFe:mFe 3+ =0.1 ratio, and iron powder was added thereto for reaction. After the reaction was complete, it was placed in a low-temperature thermostatic bath for crystallization treatment at a crystallization temperature of -5°C. After suction filtration, an iron removal leaching solution was obtained.

[0024] (3) The iron removal leaching solution obtained in step 3 was extracted using a P204-TBP extraction system. The extraction conditions were 12.5% ​​P204-10% TBP, A / O=6, and a temperature of 40° C. The extraction rate reached 99.7%.

[0025] Embodiment 3

[0026] (1) using titanium dioxide waste acid to leach scandium-containing waste slag finely ground to less than 150 μm, controlling the liquid-solid ratio of titanium dioxide waste acid to scandium-containing waste slag to be 10; the leaching temperature is 60° C.; leaching for 60 minutes, and obtaining a leachate after suction filtration;

[0027] (2) The leaching solution obtained in step 1 is subjected to Fe 3+ Content test, according to mFe:mFe 3+ =0. Iron powder is added thereto for reaction. After the reaction is complete, it is placed in a low-temperature constant temperature bath for crystallization treatment at a crystallization temperature of 0°C. After suction filtration, an iron-removing leaching solution is obtained.

[0028] (3) The iron removal leaching solution obtained in step 3 was extracted using a P204-TBP extraction system. The extraction conditions were 15% P204-15% TBP, A / O=8, and a temperature of 50° C. The extraction rate reached 99.9%.

[0029] Embodiment 4

[0030] (1) using titanium dioxide waste acid to leach scandium-containing waste slag finely ground to less than 150 μm, controlling the liquid-solid ratio of titanium dioxide waste acid to scandium-containing waste slag to be 12; the leaching temperature is 70° C.; leaching for 90 minutes, and obtaining a leachate after suction filtration;

[0031] (2) The leaching solution obtained in step 1 is subjected to Fe 3+ Content test, according to mFe:mFe 3+ =0.25, add iron powder to react, after the reaction is complete, place in a low temperature thermostatic bath for crystallization treatment, the crystallization temperature is 10°C, and filter to obtain the iron removal leaching solution.

[0032] (3) The iron removal leaching solution obtained in step 3 was extracted using a P204-TBP extraction system. The extraction conditions were 20% P204-20% TBP, A / O=10, and a temperature of 70° C. The extraction rate reached 99.9%.

[0033] Figure: Products after crystallization and the formation of the third phase during the extraction process in different cases.

Claims

1. A method for recovering scandium and producing green vitriol from a scandium-containing solution by emulsification-free extraction, characterized in that: The steps include: Step 1: grind the scandium-containing waste slag to less than 150 μm in a certain proportion and leach it with titanium dioxide waste acid at a certain temperature for a certain period of time, and obtain the leachate after suction filtration; Step 2: According to a certain mFe:mFe 3+ Add iron powder to the leaching solution in a certain proportion, after the iron powder reacts, transfer the leaching solution into a low-temperature constant temperature tank for crystallization, and obtain the iron-removing leaching solution and green vitriol after suction filtration; Step 3: extract the iron removal leaching solution obtained in step 2 using a P204-TBP extraction system under certain extraction conditions to obtain a scandium-containing and non-solvent solution.

2. A method for recovering scandium and producing green vitriol from a scandium-containing solution by emulsification-free extraction according to claim 1, characterized in that In step 1, the solid-liquid ratio of the titanium dioxide waste acid to the scandium-containing waste slag is 1:6 to 1:

12.

3. A method for recovering scandium and producing green vitriol from a scandium-containing solution by emulsification-free extraction according to claim 1, characterized in that In step 1, the leaching temperature of the leaching solution is 25-80° C. and the leaching time is 30-90 min.

4. The method of claim 1, wherein the method comprises extracting and recovering scandium from a scandium-containing solution without emulsification and producing green vitriol. The ratio of iron powder added in step 2 is mFe:mFe 3+ =0.1~0.5, and the crystallization temperature is -10~10℃.

5. The method of claim 1, wherein the method comprises extracting and recovering scandium from a scandium-containing solution without emulsification and producing green vitriol. The ratio of the P204-TBP extraction system used for extraction in step 3 is 1 to 10, the concentration of P204 is 10% to 20%, the concentration of TBP is 5% to 20%, and the temperature is 25 to 70°C.

Images