A synergistic extraction system and method for microwave-assisted extraction of indium

Abstract

The present invention relates to the technical field of indium extraction, and particularly to a synergistic extraction system and method for microwave-assisted co-extraction of indium. The extractant used in the synergistic extraction system for microwave-assisted extraction of indium is Cyanex272 + Versatic 10 acid. The novel synergistic extraction system for microwave-assisted extraction of indium provided by the present invention can achieve efficient and selective extraction of indium under certain conditions, with almost no co-extraction of impurity metals such as zinc and aluminum. At the same time, the introduction of microwave can shorten the time to reach extraction equilibrium. The present invention can provide a new method and new idea for the efficient and selective extraction of indium.

Description

Technical Field

[0001] The present invention relates to the technical field of indium extraction, and particularly relates to a synergistic extraction system and method for microwave-assisted co-extraction of indium. Background Art

[0002] Indium is the main raw material for manufacturing electronic and optical devices. Most of the indium is used to produce ITO (indium tin oxide), and part of it is used to produce InP, copper indium gallium selenide thin films (CIGS), etc. Therefore, many countries list indium as a key strategic metal. With the continuous development of electronic technology, the demand for indium is gradually increasing. Indium is usually recovered from the by-products of zinc, copper, and aluminum smelting. In the future, it is very promising to recover indium from waste LCD or LED and zinc oxide dust.

[0003] Liquid-liquid extraction is a mature process for separating indium from indium-containing solutions. Indium is usually extracted from aqueous solutions using D2EHPA. However, D2EHPA can also extract zinc and aluminum in multi-metal solution systems, resulting in a decrease in indium purity. To overcome the limitations of D2EHPA in indium extraction, some researchers have developed ionic liquids for indium extraction, but the high cost and difficult recovery of ionic liquids limit their large-scale production. Synergistic extraction has been widely studied due to its advantages such as good selectivity and high extraction efficiency. Sankum-Nusen et al. used the synergistic extraction system LIX 63 + Versatic 10 acid to extract 86% of indium at pH = 3.0. Fan et al. studied the process of synergistic extraction of indium from a mixture of CA100 and N235, and the extraction distribution ratio of indium reached the maximum value at pH = 3.0, x CA100 = 0.8. Ma et al. studied the extraction of gallium, indium, and zinc by the synergistic extraction system CA12 + N1923, and found that the synergistic extraction system CA12 + N1923 had a synergistic effect on indium extraction at pH = 3.0, x CA12 = 0.2. Hisanori IMURA et al. studied the synergistic extraction of gallium and indium by a mixture of 2,4-pentanedione and 3,5-dichlorophenol, and found that the mechanism of synergistic extraction was caused by outer-sphere complexation. In recent years, microwave has been widely used in the fields of pyrometallurgical roasting and hydrometallurgical leaching. Microwave heating is different from the traditional heating method from outside to inside, and microwave heating of materials is caused by dielectric loss and body heating in the electromagnetic field, with the characteristics of fast heating rate, selectivity, and uniform heating. Microwave is an electromagnetic wave that causes polar molecules to vibrate rapidly in the magnetic field, thereby generating energy. Therefore, microwave-assisted extraction of metal ions from aqueous solutions is theoretically feasible. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a novel co - extraction system for microwave - assisted extraction of indium. Under certain conditions, this co - extraction system can achieve efficient and selective extraction of indium, with almost no co - extraction of impurity metals such as zinc and aluminum. Meanwhile, the introduction of microwaves can shorten the time to reach extraction equilibrium. The present invention can provide a new method and new idea for the efficient and selective extraction of indium.

[0005] In the first aspect, the present invention provides a co - extraction system for microwave - assisted extraction of indium, and the extractants used are Cyanex272 + Versatic 10 acid. The present invention uses the microwave - assisted novel co - extraction system Cyanex272 + Versatic 10 acid to co - extract indium. The mechanism of co - extraction is that the hydrogen ions ionized from Versatic 10 acid combine with - P = O to form an O - H + -----O = P bond, thereby exerting a co - extraction effect. The present invention uses the novel co - extraction system Cyanex272 + Versatic 10 acid to co - extract indium, and under certain conditions, it can efficiently and selectively extract indium.

[0006] Preferably, the volume concentration of Cyanex272 in the co - extraction system is 15 - 25%, and the volume concentration of Versatic 10 acid is 5 - 15%. In the embodiments of the present invention, the co - extraction coefficient of the co - extraction system Cyanex272 + Versatic 10 acid is greater than 1, showing a positive co - extraction effect on the extraction of indium. Especially at specific volume concentrations, the best co - extraction effect can be exerted, as shown in Figure 1 (D - extraction distribution ratio of indium; R - co - extraction coefficient of indium).

[0007] The present invention uses the microwave - assisted novel co - extraction system Cyanex272 + Versatic 10 acid to co - extract indium. The optimal concentration of the extractants Cyanex272 + Versatic 10 acid is 30% (V / V), where: X Cyanex272 = 20%, X Versatic 10 acid = 10%.

[0008] Preferably, in the co - extraction system, the volume concentration of Cyanex272 is 20%, and the volume concentration of Versatic 10 acid is 10%. The diluent used is preferably sulfonated kerosene.

[0009] In the second aspect, the present invention provides a co - extraction method for microwave - assisted extraction of indium, which uses the above co - extraction system for extraction, including the following steps:

[0010] 1) Prepare the extraction aqueous phase and adjust the pH.

[0011] 2) Mix the extracted aqueous phase with the co - extraction system and perform microwave - assisted extraction to obtain the indium - loaded organic phase.

[0012] 3) Strip indium from the indium - loaded organic phase.

[0013] Further preferably, in step 1), adjust the pH of the extracted aqueous phase to 2 - 2.5; the present invention uses a novel co - extraction system Cyanex272+Versatic 10 acid to co - extract indium. Under the condition of controlling the pH of the aqueous phase, indium can be efficiently and selectively extracted, while hardly extracting impurity metals such as zinc and aluminum.

[0014] Preferably, adjust the pH of the extracted aqueous phase to 2.

[0015] In the present invention, the co - extraction system Cyanex272+Versatic 10 acid has good selectivity for indium, with a large separation coefficient, and hardly extracts zinc and aluminum at pH = 2.

[0016] Preferably, in step 1), the main metal ions in the extracted aqueous phase include In, Zn, and Al.

[0017] Further preferably, in step 1), the preparation of the extracted aqueous phase includes: ultrasonic - microwave combined leaching of indium from zinc oxide fume by sulfuric acid to obtain a leaching solution, reduction with iron powder, ultrasonic - enhanced calcium carbonate precipitation of indium, then drying the precipitation residue, and dissolving with sulfuric acid to obtain the extracted aqueous phase.

[0018] Preferably, in step 2), the volume ratio of the co - extraction system to the extracted aqueous phase is 2:1 - 1:3.

[0019] Further preferably, in step 2), the contact time for extraction is 1 - 5 min, and the microwave operation mode is a constant - temperature mode or a constant - power mode; preferably, the temperature in the constant - temperature mode is 35 - 40 °C; the microwave power in the constant - power mode is 50 - 90 W.

[0020] Preferably, in step 3), microwave - assisted stripping of indium is performed, with a contact time of 1 - 3 min, a temperature of 35 - 40 °C and / or a microwave power of 50 - 90 W. Microwave assistance is also used when stripping indium from the indium - loaded organic phase, which can shorten the time to reach equilibrium for stripping.

[0021] Further preferably, in step 3), indium is back-extracted from the indium-loaded organic phase with hydrochloric acid, and the concentration of hydrochloric acid is 1.8 - 2.2 mol / L, preferably 2 mol / L. In the present invention, microwave-assisted novel synergistic extraction system Cyanex272 + Versatic 10 acid is used for synergistic extraction of indium, and after extraction, using 2 mol / L hydrochloric acid to back-extract indium from the indium-loaded organic phase has better effect.

[0022] Preferably, the volume ratio of the indium-loaded organic phase to hydrochloric acid is 1.5:1 - 3:1.

[0023] In the present invention, microwave-assisted novel synergistic extraction system Cyanex272 + Versatic 10 acid is used for synergistic extraction of indium. After extraction, the organic phase after hydrochloric acid back-extraction can be recycled multiple times after being washed with oxalic acid and sulfuric acid.

[0024] Preferably, after the organic phase after hydrochloric acid back-extraction is washed with oxalic acid with a preferred concentration of 100 g / L and sulfuric acid with a preferred concentration of 100 g / L, the organic phase is recycled preferably 3 times.

[0025] The beneficial effects of the present invention are at least as follows: The present invention uses microwave-assisted novel synergistic extraction system Cyanex272 + Versatic 10 acid for synergistic extraction of indium, which can efficiently and selectively extract indium. The present invention uses microwave-assisted synergistic extraction of indium. Utilizing the inside-out and continuous and uniform heating of microwave can increase the contact area between the extraction aqueous phase and the organic phase, improve the extraction rate and shorten the time for extraction to reach equilibrium. The present invention uses microwave-assisted synergistic extraction of indium, which is simple and convenient to operate, and can realize industrial scale and process production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the 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, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 It is the synergistic extraction distribution ratio diagram (a) and the synergistic extraction coefficient (b) of the synergistic extraction system of indium provided by the embodiment of the present invention.

[0028] Figure 2 It is the process flow diagram of the microwave-assisted novel synergistic extraction system provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without any creative work fall within the scope of protection of the present invention.

[0030] It should be understood that the following embodiments are only illustrative explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered by the scope of protection intended by the present invention. Unless otherwise specified, the raw materials and reagents used in the following embodiments are commercially available products or can be prepared by known methods. For those not specifying specific techniques or conditions in the embodiments, they are conventional methods or are carried out according to the techniques or conditions described in the literature in this field, or according to the product instructions. For those reagents and instruments not indicating the manufacturer, they are all conventional products that can be obtained through regular channels.

[0031] In an embodiment of the present invention, a novel co-extraction method for co-extracting indium from an acid solution of indium-rich precipitation residue is provided, including the following steps:

[0032] 1) Use ultrasonic-microwave synergistic leaching to prepare the leaching solution. The process conditions are sulfuric acid 180 g / L, ultrasonic power 200 W, microwave power 200 W, liquid-solid ratio 8:1, and leaching time 30 minutes.

[0033] 2) Perform iron powder reduction on the zinc oxide fume leaching solution obtained after filtration, with ultrasonic-enhanced reduction for 20 minutes to reduce Fe 3+ in the leaching solution to Fe 2+ , facilitating subsequent precipitation of indium.

[0034] 3) Pour the leaching solution after iron powder reduction into a 500 ml four-necked flask, place the four-necked flask in an ultrasonic-microwave chemical reactor, insert a pH meter and a temperature thermocouple into the four-necked flask to monitor the solution pH value and temperature.

[0035] 4) Turn on the ultrasonic generator, set the ultrasonic power to 200 W, and at the same time turn on the microwave reactor but do not run the microwave reactor to record the solution temperature; at the same time, slowly add calcium carbonate powder. When the solution pH reaches 4, immediately turn off the ultrasonic generator, and at the same time quickly filter the precipitation solution, wash the precipitation residue 5 times with deionized water, and then place the precipitation residue in an oven to dry for 24 hours.

[0036] 5) The dried precipitate residue was ground and then dissolved in sulfuric acid. The sulfuric acid concentration was 100 g / L, the liquid-solid ratio was 5:1, and ultrasonic-assisted dissolution was carried out for 30 minutes. After dissolution, vacuum filtration was performed to obtain the extraction mother liquor (i.e., the extraction aqueous phase in the example), and an inductively coupled plasma optical emission spectrometer (ICP-OES) was used to measure the ion concentrations of indium, zinc, and aluminum in the extraction mother liquor.

[0037] 6) The extractants Cyanex272 and Versatic 10 acid (neo-decanoic acid) were mixed and then diluted with sulfonated kerosene. Cyanex272 + Versatic 10 acid = 30% (V / V), where: X Cyanex272 = 20%, X Versatic 10 = 1 - X Cyanex272 (V / V). Then, microwave-assisted extraction was carried out according to a certain phase ratio, pH, contact time, temperature, and different microwave powers.

[0038] 7) Indium was back-extracted from the indium-loaded organic phase with 2 mol / L hydrochloric acid.

[0039] Example 1

[0040] This example provides a synergistic extraction system for microwave-assisted extraction of indium. The concentration of the extractants Cyanex272 + Versatic 10 acid is 30% (V / V), where: X Cyanex272 = 20%, X Versatic 10 acid = 10%, and the diluent is sulfonated kerosene.

[0041] This example also provides a synergistic extraction method for microwave-assisted extraction of indium: First, prepare the extraction aqueous phase according to the method of the above example. The main metal ion concentrations in the extraction aqueous phase are In: 0.795 g / L, Zn: 6.7 g / L, and Al: 0.58 g / L. Then, the extraction aqueous phase and the synergistic extraction system Cyanex272 + Versatic 10 acid diluted with kerosene were mixed and placed in a microwave reactor for microwave-assisted extraction. Among them, the pH of the aqueous phase was adjusted to 2.0, the ratio of the organic phase (extraction system) to the aqueous phase (extraction aqueous phase) was 1:1, the contact time was 5 minutes, the temperature was 35 °C, the stirring rate was 500 rpm, the microwave operation mode was the constant temperature mode, and the concentration of the extractants Cyanex272 + Versatic 10 acid was 30% (V / V), where: X Cyanex272 = 20%, X Versatic 10 acid= 10%, and the diluent is sulfonated kerosene. At this time, the extraction rates of indium, zinc, and aluminum are 99.84%, 0.15%, and 0.34% respectively. Then, indium is microwave-assisted back-extracted from the indium-loaded organic phase with hydrochloric acid at a hydrochloric acid concentration of 2 mol / L, an organic phase to water phase ratio of 1.5:1, a microwave power of 90 W, and a contact time of 3 minutes, and the back-extraction rate of indium is 99.81%.

[0042] Example 2

[0043] The method of Example 1 is adopted, with the differences being: adjusting the pH of the aqueous phase to 2.0, the organic phase to aqueous phase ratio to 1:2, the contact time to 5 minutes, the temperature to 35 °C, the stirring rate to 500 rpm, the microwave operation mode to the constant temperature mode, and the concentration of the extractant Cyanex272 + Versatic 10 acid to 30% (V / V), where: X Cyanex272 = 20%, X Versatic 10 acid = 10%, and the diluent is sulfonated kerosene. At this time, the extraction rates of indium, zinc, and aluminum are 95.71%, 0.87%, and 0.23% respectively. Then, indium is microwave-assisted back-extracted from the indium-loaded organic phase with hydrochloric acid at a hydrochloric acid concentration of 2 mol / L, an organic phase to water phase ratio of 1.5:1, a microwave power of 90 W, and a contact time of 3 minutes, and the back-extraction rate of indium is 99.79%.

[0044] Example 3

[0045] The method of Example 1 is adopted, with the differences being: adjusting the pH of the aqueous phase to 2.0, the organic phase to aqueous phase ratio to 1:3, the contact time to 5 minutes, the temperature to 35 °C, the stirring rate to 500 rpm, the microwave operation mode to the constant temperature mode, and the concentration of the extractant Cyanex272 + Versatic 10 acid to 30% (V / V), where: X Cyanex272 = 20%, X Versatic 10 acid = 10%. At this time, the extraction rates of indium, zinc, and aluminum are 93.21%, 0.79%, and 0.98% respectively. Then, indium is microwave-assisted back-extracted from the indium-loaded organic phase with hydrochloric acid at a hydrochloric acid concentration of 2 mol / L, an organic phase to water phase ratio of 1.5:1, a microwave power of 90 W, and a contact time of 3 minutes, and the back-extraction rate of indium is 99.76%.

[0046] Example 4

[0047] The method of Example 1 is adopted, with the differences being: adjusting the pH of the aqueous phase to 2.0, the organic phase to aqueous phase ratio to 1:3, the contact time to 1 minute, the temperature to 35 °C, the stirring rate to 500 rpm, the microwave operation mode to the constant temperature mode, and the concentration of the extractant Cyanex272 + Versatic 10 acid to 30% (V / V), where: X Cyanex272 = 20%, X Versatic 10 acid= 10%, and the diluent is sulfonated kerosene. At this time, the extraction rates of indium, zinc, and aluminum are 99.94%, 0.06%, and 0.23% respectively. Then, indium is microwave-assisted back-extracted from the indium-loaded organic phase with hydrochloric acid at a hydrochloric acid concentration of 2 mol / L, an organic phase to water phase ratio of 1.5:1, a microwave power of 90 W, and a contact time of 3 minutes, and the back-extraction rate of indium is 99.53%.

[0048] Example 5

[0049] The method of Example 1 is adopted, with the differences being: adjusting the pH of the aqueous phase to 2.0, the organic phase to aqueous phase ratio to 1:3, the contact time to 1 minute, the temperature to 40 °C, the stirring rate to 500 rpm, the microwave operation mode to the constant temperature mode, and the concentration of the extractant Cyanex272 + Versatic 10 acid to 30% (V / V), where: X Cyanex272 = 20%, X Versatic 10 acid = 10%, and the diluent is sulfonated kerosene. At this time, the extraction rates of indium, zinc, and aluminum are 99.96%, 0.12%, and 0.90% respectively. Then, indium is microwave-assisted back-extracted from the indium-loaded organic phase with hydrochloric acid at a hydrochloric acid concentration of 2 mol / L, an organic phase to water phase ratio of 1.5:1, a microwave power of 90 W, and a contact time of 3 minutes, and the back-extraction rate of indium is 99.94%.

[0050] Example 6

[0051] The method of Example 1 is adopted, with the differences being: adjusting the pH of the aqueous phase to 2.0, the organic phase to aqueous phase ratio to 1:3, the contact time to 1 minute, the microwave power to 70 W, the stirring rate to 500 rpm, the microwave operation mode to the constant power mode, and the concentration of the extractant Cyanex272 + Versatic 10 acid to 30% (V / V), where: X Cyanex272 = 20%, X Versatic 10 acid = 10%, and the diluent is sulfonated kerosene. At this time, the extraction rates of indium, zinc, and aluminum are 98.27%, 1.25%, and 1.46% respectively. Then, indium is microwave-assisted back-extracted from the indium-loaded organic phase with hydrochloric acid at a hydrochloric acid concentration of 2 mol / L, an organic phase to water phase ratio of 1.5:1, a microwave power of 90 W, and a contact time of 3 minutes, and the back-extraction rate of indium is 99.89%.

[0052] Comparative Example (conventional extraction):

[0053] First, prepare the extraction aqueous phase according to the method described above, adjust the pH of the aqueous phase to 2.0, the organic phase to aqueous phase ratio to 1:3, the contact time to 1 minute, the temperature to 40 °C, the stirring rate to 500 rpm, mechanical stirring, water bath heating, and the concentration of the extractant Cyanex272 + Versatic 10 acid to 30% (V / V), where: X Cyanex272 = 20%, XVersatic 10 acid = 10%. At this time, the extraction rates of indium, zinc, and aluminum are 91.58%, 2.51%, and 1.47% respectively. It can be seen that compared with conventional extraction and microwave-assisted extraction, under the same conditions, the extraction rate of indium decreases by 8.38 percentage points compared with microwave-assisted extraction, the extraction rate of zinc increases by 2.39 percentage points, and the extraction rate of aluminum increases by 1.57 percentage points. Then, indium is stripped from the organic phase loaded with indium with hydrochloric acid, mechanically stirred, heated in a water bath, the hydrochloric acid concentration is 2 mol / L, the organic phase to water ratio is 1.5:1, the temperature is 40 °C, and the contact time is 3 minutes. The stripping rate of indium is 92.02%. It can be seen that the stripping rate of indium decreases by 7.92 percentage points compared with microwave-assisted stripping. This shows that microwave-assisted extraction of indium and microwave-assisted stripping of indium have obvious advantages compared with conventional methods. Microwave can improve the extraction rate of indium, inhibit the co-extraction of zinc and aluminum impurity elements, and has broad application prospects.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A synergistic extraction method for microwave-assisted extraction of indium, characterized in that: The following steps are involved: 1) Prepare the aqueous extraction phase and adjust the pH; 2) mixing the aqueous extraction phase with a synergistic extraction system of Cyanex272+Versatic 10 acid as an extractant and performing microwave-assisted extraction to obtain an organic phase loaded with indium; 3) stripping indium from the indium-loaded organic phase.

2. The synergistic extraction method of microwave-assisted indium extraction according to claim 1, characterized in that: The volume concentration of Cyanex272 in the synergistic extraction system is 15-25%, and the volume concentration of Versatic 10 acid is 5-15%.

3. The synergistic extraction method of microwave-assisted indium extraction according to claim 2, characterized in that: In the synergistic extraction system, the volume concentration of Cyanex272 is 20%, and the volume concentration of Versatic 10 acid is 10%.

4. The synergistic extraction method of microwave-assisted indium extraction according to claim 3, characterized in that: The diluent used is sulphonated kerosene.

5. The synergistic extraction method of microwave-assisted indium extraction according to claim 1, characterized in that: In step 1), the pH of the extraction aqueous phase is adjusted to 2-2.

5.

6. The synergistic extraction method of microwave-assisted indium extraction according to claim 5, characterized in that: In step 1), the pH of the extraction aqueous phase is adjusted to 2.

7. The synergistic extraction method of microwave-assisted indium extraction according to claim 6, characterized in that: In step 1), the metal ions in the extraction water phase include In, Zn and Al; and / or, the preparation of the extraction water phase includes: ultrasonic-microwave combined leaching of indium from zinc oxide smoke with sulfuric acid to obtain a leachate, iron powder reduction, ultrasonic enhanced calcium carbonate precipitation of indium, and then drying the precipitated residue and dissolving it with sulfuric acid to obtain an extraction water phase.

8. The synergistic extraction method of microwave-assisted indium extraction according to claim 1, characterized in that: In step 2), the volume ratio of the synergistic extraction system to the extraction aqueous phase is 2:1 to 1:

3.

9. The synergistic extraction method of microwave-assisted indium extraction according to claim 1, characterized in that: In step 2), the contact time of the extraction is 1 to 5 minutes, and the microwave operation mode is a constant temperature mode or a constant power mode.

10. The synergistic extraction method of microwave-assisted indium extraction according to claim 9, characterized in that: The temperature of the constant temperature mode is 35-40° C.; the microwave power of the constant power mode is 50-90W.

11. The synergistic extraction method of microwave-assisted indium extraction according to claim 1, characterized in that: In step 3), microwave-assisted stripping of indium is used with a contact time of 1 to 3 minutes, a temperature of 35 to 40°C and / or a microwave power of 50 to 90 W.

12. The synergistic extraction method of microwave-assisted indium extraction according to any one of claims 1 to 11, characterized in that: In step 3), hydrochloric acid is used to strip indium from the indium-loaded organic phase, and the concentration of the hydrochloric acid is 1.8-2.2 mol / L; the volume ratio of the indium-loaded organic phase to the hydrochloric acid is 1.5:1-3:

1.

13. The synergistic extraction method of microwave-assisted indium extraction according to claim 12, characterized in that: In step 3), the concentration of hydrochloric acid is 2 mol / L.

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