阅读说明：本技术 一种基于树脂法从粉煤灰中提取镓的方法 (Method for extracting gallium from fly ash based on resin method ) 是由 王永旺 徐靓 赵宇航 陈东 张云峰 李超 赵飞燕 郭志峰 范培育 于 2020-07-03 设计创作，主要内容包括：本发明提供了一种基于树脂法从粉煤灰中提取镓的方法,以粉煤灰经酸浸处理后所得的粗精液为原料,所述方法包括树脂法制备提镓原液、树脂法分离富集镓、中和除铁、转型沉镓、造液净化、电解沉积等步骤,由此实现从粉煤灰中提取镓。相对于现有工艺,本发明的方法基于树脂法,碱液等试剂的用量明显减少,无需使用铁掩蔽剂、还原剂等外加试剂,避免了大量废水的产生,经济且环保,镓的提取效率也得到了大幅提高。本发明的方法工艺稳定,运行可靠,成本可控,是一种非常具有应用前景的新型镓提取工艺。(The invention provides a method for extracting gallium from fly ash based on a resin method, which takes crude liquid obtained after the fly ash is subjected to acid leaching treatment as a raw material. Compared with the prior art, the method is based on a resin method, the dosage of reagents such as alkali liquor and the like is obviously reduced, additional reagents such as an iron masking agent, a reducing agent and the like are not needed, the generation of a large amount of waste water is avoided, the method is economical and environment-friendly, and the extraction efficiency of gallium is also greatly improved. The method has the advantages of stable process, reliable operation and controllable cost, and is a novel gallium extraction process with great application prospect.)

1. A method for extracting gallium from fly ash based on a resin method takes crude liquid obtained after the fly ash is subjected to acid leaching treatment as a raw material, and is characterized by comprising the following steps:

s1: adsorbing the crude liquid by passing through macroporous strong-base anion exchange resin, eluting the adsorbed resin by using 0.5-5 wt% hydrochloric acid solution as first eluent, and collecting the first eluent to concentrate to obtain gallium-extracting stock solution;

s2: adsorbing the gallium extraction stock solution by gallium extraction resin, eluting the resin after adsorption by using an acid solution with the concentration of 0.1-1 mol/L as a second eluent to obtain gallium extraction resin eluent, wherein the gallium extraction resin is selected from chelate resin with amino and/or pyridyl on a framework or weakly basic anion exchange resin;

s3: adding a first alkali solution into the gallium extracting resin eluent to ensure that Fe in the eluent is Fe³⁺Converting into precipitate and filtering to obtain first GaO-containing product₂ ^-A solution;

s4: to the first GaO-containing layer₂ ^-Adding acid into the solution to adjust the pH value to 4.5-7 so as to ensure that the GaO₂ ^-Converting into precipitate, filtering, adding second alkaline solution into the filtered precipitate to dissolve to form second GaO-containing solution₂ ^-A solution; and

s5: adding the second GaO-containing solution₂ ^-And removing impurities from the solution to obtain an electrolytic stock solution, and performing electrolytic deposition on the electrolytic stock solution to obtain the gallium metal.

2. The method according to claim 1, wherein in the step S1, the flow rate of the crude semen is 1-3 BV/h, the adsorption temperature is 25-85 ℃, preferably 60-80 ℃; and/or

The flow rate of the first eluent is 1-3 BV/h.

3. The method according to claim 1 or 2, wherein in step S1, the collected data is collectedThe first eluent is GaCl concentrated into₃The concentration is 1.3-2.0 g/L, and the gallium extracting stock solution is obtained.

4. The method according to any one of claims 1 to 3, wherein in step S2, the gallium-extracting resin is selected from 2-aminopyridine resin, 3-aminopyridine resin, 4-aminopyridine resin, 2-aminomethylpyridine resin, 3-aminomethylpyridine resin, 4-aminomethylpyridine resin, or weakly basic anion exchange resin D301; and/or

The flow rate of the gallium extraction stock solution is 0.2-1 BV/h, the adsorption temperature is 20-40 ℃, and the room temperature is preferred.

5. The method according to any one of claims 1 to 4, wherein in step S2, the second eluent is prepared from one or more of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, chloroacetic acid; the flow rate of the second eluent is 1-3 BV/h.

6. The method according to any one of claims 1 to 5, wherein in step S3, the first alkali solution is a sodium hydroxide solution with a concentration of 20 to 50 wt%.

7. The method according to any one of claims 1 to 6, wherein in the step S4, the second alkali solution is a sodium hydroxide solution with a concentration of 2 to 5 mol/L.

8. The method according to any one of claims 1 to 7, wherein the step S5 further comprises the steps of:

s501: using CaO and Na in sequence₂S and H₂O₂For the second GaO-containing₂ ^-Removing impurities from the solution and oxidizing to obtain an electrolytic stock solution; and

s502: and carrying out electrolytic deposition on the electrolytic stock solution to obtain 3N metal gallium, and washing by sequentially using 10-20 wt% of sodium hydroxide solution and 10-20 wt% of hydrochloric acid solution to obtain 4N metal gallium.

9. The method according to claim 8, wherein the step S501 comprises the following process: to the second GaO-containing layer₂ ^-Adding CaO with the weight being 8-15% of the weight of the solution into the solution, reacting for 2-4 h at 90-110 ℃, and filtering out solids; then adding Na accounting for 8-15% of the weight of the filtrate into the obtained filtrate₂S, reacting for 2-4 hours at 80-90 ℃, and filtering out solids; finally, adding 30 wt% of H with the weight being 1-5% of the weight of the filtrate into the obtained filtrate₂O₂And reacting for 0.5-3 h at 50-70 ℃.

10. The method according to claim 8 or 9, wherein during the electrolytic deposition, the electrolytic temperature is 40-50 ℃, the electrode spacing is 3cm, the interelectrode voltage is 3V, the current is 190-200A, and when the gallium content in the electrolytic tail liquid is less than 300mg/L, the electrolysis is finished.

Technical Field

The invention relates to the field of hydrometallurgy, in particular to a method for extracting gallium from fly ash based on a resin method.

Background

Gallium is an important rare metal, and with the deepening of the international mining structure, the development and utilization of the rare metal are being improved to the strategic level by many countries. At present, the yield of native gallium all over the world is about 300t/a, the recycling level is extremely low, and due to the concomitant relation, if the yield cannot be improved, serious shortage will occur in the future 20-30 years.

Gallium is mainly dispersed in bauxite, lead-zinc ore, coal, and copper and iron ores, and has an average content of about 50 μ g/g, and about 90% of gallium is currently recovered from alumina production worldwide. In recent years, the extraction of alumina from fly ash is a research and development hotspot, the content of gallium in fly ash can reach 82.5 mug/g, the storage amount of gallium in inner Mongolia quasi-Gel coal mines is as high as 85.6 million tons, which is about half of the global storage amount, so that the extraction of gallium from the process for producing alumina from fly ash is very important.

In the process of producing alumina by using fly ash, hydrochloric acid is generally used for carrying out acid leaching treatment on the fly ash, and Fe and Ga existing in the fly ash are Fe³⁺And Ga³⁺The form of the extract is put into pickle liquor (namely crude semen) and then a subsequent extraction process is carried out. For example, chinese patent CN 102191384a, "a method for extracting gallium from fly ash" discloses a method for extracting gallium from circulating fluidized bed fly ash, which uses cation exchange resin to directly recover gallium from pickle liquor, and the method requires that all iron in the solution be extractedIon precipitation, high alkali consumption; for another example, CN 104018012a, "a method for extracting gallium from aluminum chloride solution" discloses a method for extracting gallium from aluminum chloride solution, which comprises adding an iron ion masking agent to pickle liquor to reduce iron ions, and then recovering gallium through anion exchange resin, wherein the iron ion masking agent can be sodium sulfite, ascorbic acid, iron powder, etc.; at normal temperature, the using amount of ascorbic acid is large, the cost is high, the ascorbic acid reducing solution is not stable enough during heating, the reduction is not complete enough when sodium sulfite is adopted, the adsorption effect of gallium is poor, when iron powder is used for reduction, a large amount of ferrous chloride solution (the iron content is twice of that in the stock solution) is generated while gallium is extracted, and the difficulty in waste liquid treatment is increased.

Based on the situation of the prior art, the process for extracting gallium from the process for producing alumina by using fly ash still has further improvement space in the aspects of extraction efficiency, production cost reduction and the like.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a novel gallium extraction method with lower cost and higher production efficiency, and aims to provide a method for extracting gallium from fly ash based on a resin method.

The invention provides a method for extracting gallium from fly ash based on a resin method, which takes crude liquid obtained after the fly ash is subjected to acid leaching treatment as a raw material and comprises the following steps:

s1: adsorbing the crude liquid by passing through macroporous strong-base anion exchange resin, eluting the adsorbed resin by using 0.5-5 wt% hydrochloric acid solution as first eluent, and collecting the first eluent to concentrate to obtain gallium-extracting stock solution;

s2: adsorbing the gallium extraction stock solution by gallium extraction resin, eluting the resin after adsorption by using an acid solution with the concentration of 0.1-1 mol/L as a second eluent to obtain gallium extraction resin eluent, wherein the gallium extraction resin is selected from chelate resin with amino and/or pyridyl on a framework or weakly basic anion exchange resin;

s3: adding a first alkali solution into the gallium extracting resin eluent to ensure that Fe in the eluent is Fe³⁺Converting into precipitate and filtering to obtain first GaO-containing product₂ ^-A solution;

s4: to the first GaO-containing layer₂ ^-Adding acid into the solution to adjust the pH value to 4.5-7 so as to ensure that the GaO₂ ^-Converting into precipitate, filtering, adding second alkaline solution into the filtered precipitate to dissolve to form second GaO-containing solution₂ ^-A solution; and

s5: adding the second GaO-containing solution₂ ^-And removing impurities from the solution to obtain an electrolytic stock solution, and performing electrolytic deposition on the electrolytic stock solution to obtain the gallium metal.

In the method provided by the invention, a large amount of Fe in the pickle liquor is absorbed by using macroporous type strong-base anion exchange resin³⁺And Ga³⁺Adsorbing the obtained eluent by using gallium extracting resin, wherein the gallium extracting resin is used for adsorbing Fe³⁺And Ga³⁺Has adsorption capacity obviously different from that of macroporous strongly basic anion exchange resin, and is used for Ga³⁺The adsorption capacity of the gallium-enriched macroporous strongly basic anion exchange resin is higher (in some embodiments, the Fe/Ga ratio in the eluent of the macroporous strongly basic anion exchange resin can reach about 150, and the Fe/Ga ratio in the eluent of the gallium-extracting resin can be reduced to about 10), so that the gallium-enriching effect can be achieved, and meanwhile, the absolute amount of iron can be remarkably reduced through the adsorption of the gallium-extracting resin, so that the dosage of alkali liquor in the subsequent process can be reduced. After absorbing by gallium extracting resin, adding alkali liquor and Fe into the obtained eluent³⁺Conversion to Fe (OH)₃Precipitate (commonly known as iron mud) is separated out, Ga³⁺All are converted into GaO₂ ^-Left in the first GaO-containing layer₂ ^-In solution, thereby realizing Fe³⁺And Ga³⁺Separation (i.e. neutralization iron removal step). The first GaO content after iron mud filtering₂ ^-The solution contains a large amount of NaCl and other impurities which are difficult to be removed by an impurity removing agent directly, so that the second GaO-containing solution with lower impurity content can be obtained by acidification (i.e. a step of converting and depositing gallium) and alkali liquor adding for dissolving again₂ ^-The solution can be simply purified to obtain qualified electrolytic stock solution (namely a solution preparation purification step), and the electrolytic stock solution is subjected to electrolytic deposition to obtain metal gallium, so that the solution is preparedThe extraction and recovery of gallium are carried out.

In the method provided by the invention, in the step S1, the flow rate of the crude semen can be 1-3 BV/h, the adsorption temperature can be 25-85 ℃, and preferably, the adsorption temperature can be 60-80 ℃.

In the method provided by the invention, in the step S1, a 0.5-3 wt% hydrochloric acid solution may be used as the first eluent, for example, a 1 wt%, 2 wt%, or 3 wt% hydrochloric acid solution.

In the method provided by the invention, in the step S1, the flow rate of the first eluent can be 1-3 BV/h, and the temperature during elution can be room temperature (about 25 ℃).

In the method provided by the present invention, in the step S1, the macroporous strongly basic anion exchange resin may be of a common type, including but not limited to 201 × 7, 201 × 4, LSC-Fe, and the like.

In the method provided by the present invention, in the step S1, GaCl in which the first eluent is concentrated is collected₃The concentration is 1.3-2.0 g/L, and the gallium extracting stock solution is obtained.

In the method of the present invention, in the step S2, the gallium extracting resin may be a p-Ga resin³⁺The resin having a higher adsorption capacity is preferably selected from the group consisting of 2-aminopyridine resin (2-APR), 3-aminopyridine resin (3-APR), 4-aminopyridine resin (4-APR), 2-aminomethylpyridine resin (2-AMPR), 3-aminomethylpyridine resin (3-AMPR), 4-aminomethylpyridine resin (4-AMPR) and weakly basic anion exchange resin (e.g., D301).

In the method provided by the invention, in the step S2, the flow rate of the gallium extraction stock solution can be 0.2-1 BV/h, the adsorption temperature can be 20-40 ℃, and the preferred temperature can be room temperature.

In the method provided by the present invention, in step S2, the second eluent may be prepared from one or more of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and chloroacetic acid; the concentration thereof may preferably be 0.2 to 0.5 mol/L.

In the method provided by the invention, in the step S2, the flow rate of the second eluent can be 1-3 BV/h, and the temperature during elution can be room temperature.

In the method provided by the present invention, in the step S3, the first alkali solution may be a sodium hydroxide solution with a concentration of 20 to 50 wt% (for example, the concentration may be 20, 30, 40, or 50 wt%), and the amount of the first alkali solution is such that Fe is added³⁺Converted into iron mud precipitate, Ga³⁺Conversion to GaO₂ ^-The standard is. For example, the amount of the first alkali solution added may be such that the NaOH concentration in the solution obtained after the reaction with the added alkali solution is 1 mol/L.

In the method provided by the invention, in the step S4, the acid for adjusting the pH value may be a concentrated hydrochloric acid solution with a concentration of 20 to 30 wt%.

In the method provided by the invention, in the step S4, the second alkali solution is a sodium hydroxide solution with a concentration of 2-5 mol/L (for example, the concentration may be 2, 3, 4, or 5mol/L), and the addition amount of the second alkali solution is such that gallium mud is converted into GaO₂ ^-The standard is. For example, the amount of the second alkali solution added can be that the molar ratio of NaOH to Ga is 1.1-1.2: 1.

in the method provided by the invention, the method for filtering the iron mud and the gallium mud can be a method commonly used in the field, for example, plate-and-frame filtration.

In the method provided by the present invention, the step S5 further includes the following steps:

s501: using CaO and Na in sequence₂S and H₂O₂For the second GaO-containing₂ ^-Removing impurities from the solution and oxidizing to obtain an electrolytic stock solution; and

s502: and carrying out electrolytic deposition on the electrolytic stock solution to obtain 3N metal gallium, and washing by sequentially using 10-20 wt% of sodium hydroxide solution and 10-20 wt% of hydrochloric acid solution to obtain 4N metal gallium.

In the method provided by the present invention, the step S501 may include the following processes: to the second GaO-containing layer₂ ^-Adding CaO with the weight being 8-15% of the weight of the solution into the solution, reacting for 2-4 h at 90-110 ℃, and filtering out solids; then adding Na accounting for 8-15% of the weight of the filtrate into the obtained filtrate₂S, reacting for 2-4 hours at 80-90 ℃, and filtering out solids; finally, to the rearAdding 30 wt% of H with the weight being 1-5% of the weight of the filtrate into the obtained filtrate₂O₂And reacting for 0.5-3 h at 50-70 ℃.

CaO、Na₂S can be used as an impurity removal agent to effectively remove the second GaO-containing substances₂ ^-VO present in solution₄ ^3-、FeO₂ ^-Etc. are equal to H₂O₂The oxidant can remove S in the solution^2-The second GaO containing gas is obtained after impurity removal and oxidation steps₂ ^-The solution can be changed into electrolytic stock solution according to the electrolysis requirement.

In the method provided by the invention, the process of electrolytic deposition can adopt a conventional technology, and preferably can be the following process: the electrolysis temperature is 40-50 ℃, the electrode distance is 3cm, the interelectrode voltage is 3V, the current is 190-200A, and when the gallium content in the electrolysis tail liquid is less than 300mg/L, the electrolysis is finished. The electrolysis tail liquid can also be returned to the liquid making and purifying step for recycling.

In the method provided by the invention, the purity of the metal gallium (crude gallium) obtained by electrolysis is about 99-99.9%, and can reach 3N level, and the metal gallium (refined gallium) obtained after washing can reach 4N level.

The method for extracting gallium from fly ash provided by the invention has the following advantages:

(1) the method of the invention obviously reduces the absolute amount of iron while enriching gallium by using gallium-extracting resin, thereby greatly reducing the dosage of alkali liquor and improving the economy of the gallium-extracting process.

(2) The method also comprises the treatment steps of neutralization deferrization, transformation gallium precipitation, liquid making purification and the like, and can obtain qualified electrolytic stock solution through less reagent dosage so as to obtain a final metal gallium product, wherein the recovery rate of 4N gallium is higher relative to the gallium content in the gallium extracting stock solution.

(3) The method does not need to use an iron masking agent, a reducing agent and other additional reagents, does not generate a large amount of ferrous chloride solution, and is economical and environment-friendly.

(4) In the method, the resin can be continuously used for a long time, and materials such as acid liquor, alkali liquor and the like have low cost and wide sources, so that the cost of the gallium extraction process is further reduced.

In a word, the method has the advantages of stable process, reliable operation, controllable cost and higher extraction efficiency, and is a novel gallium extraction process with great application prospect.

Drawings

FIG. 1 is a flow chart of the process for extracting gallium from fly ash based on a resin method.

Detailed Description

The technical solution of the present invention is further described in detail with reference to the following specific examples.