A method for preparing gallium oxide from a gallium-containing solution

Abstract

The application provides a method for preparing gallium oxide from a gallium-containing solution, which comprises the following steps: sequentially subjecting the gallium-containing solution to resin adsorption and elution to obtain a gallium-rich solution; subjecting the gallium-rich solution to pre-neutralization by using a composite precipitant, wherein the composite precipitant comprises an alkali and an acid anion salt, to obtain a gallium-rich neutralized solution; subjecting the gallium-rich neutralized solution to aging crystallization to obtain a hydrated gallium product after separation; and subjecting the hydrated gallium product to calcination to obtain a gallium oxide product, wherein the tail gas generated in the calcination is absorbed and then returned for the elution of gallium. The gallium-containing solution is enriched by resin adsorption and elution, and then subjected to pre-neutralization and aging crystallization, so that the gallium is precipitated and separated in the form of a hydrated gallium product, and the recovery rate of the gallium is high. The composite precipitant used in the method is beneficial to the hydrolysis of the gallium into a layered hydrated gallium product, and the stability of the gallium product is improved. The absorption of the tail gas can also realize the recycling of the medium. The method has the advantages of simple process flow, simple operation, low production cost and wide application range.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical separation and extraction technology, and relates to a method for preparing gallium oxide from a gallium-containing solution. Background Technology

[0002] Gallium, as a rare and dispersed metallic element, has wide applications in fields such as metallurgy, semiconductors, chemicals, energy, and materials due to the unique properties of its metals and compounds. With the rapid development of the semiconductor industry in recent years, the demand for gallium oxide will surge. However, because gallium reserves are relatively scarce, its geographical distribution is highly uneven, and there are no independent deposits, it is often found as an associated mineral in bauxite or lead-zinc mines. Currently, most of the gallium used worldwide is recovered from the alumina production process.

[0003] Currently, gallium extraction mainly relies on aluminum industry processes, including chemical, electrochemical, extraction, and ion exchange methods. Ion exchange, primarily referring to resin adsorption separation, has become the most widely used method for extracting gallium from Bayer mother liquor produced from alumina due to its simple process, ease of operation, and lack of the need for additional additives. Coal-based resources are another important source of gallium, and extracting gallium from coal-based materials such as fly ash or gangue is also a current research focus.

[0004] CN 102534214A discloses a novel method for recovering gallium from Bayer mother liquor using chelating resin. The method includes: loading gallium extraction resin into a resin column; intermittently and dynamically adsorbing the Bayer mother liquor through the resin until saturation; washing the saturated gallium extraction resin with water; desorbing the adsorbed gallium using an acidic eluent; and treating the eluent solution by precipitation and impurity removal to obtain a relatively pure concentrated gallium-containing electrolyte, which can be electrolyzed to obtain metallic gallium. The eluted resin is then washed with water until the pH of the liquid flowing out of the exchange column is 6-8. This method uses an acidic eluent with a low pH, neutralizes the eluent solution with an alkaline solution to obtain gallium hydroxide, and then dissolves and removes impurities with an alkaline solution. This results in high consumption of neutralizing reagents, a lengthy operation process, and the inability to utilize the neutralized eluent solution. Furthermore, the electrolysis step is costly.

[0005] CN 102021334A discloses a method for extracting gallium and vanadium from the mother liquor of the Bayer process. The method includes: adsorbing the Bayer process mother liquor with an ion exchange resin; washing the saturated resin; adding BaO to the eluent to precipitate vanadium as barium vanadate; adding NaOH to the vanadium-precipitated solution to precipitate gallium as gallium hydroxide; dissolving the gallium hydroxide in NaOH solution to generate a sodium gallate solution; and electrolyzing the sodium gallate solution to obtain metallic gallium. This method, like others, uses adsorption, washing, neutralization precipitation, re-dissolution, and electrolysis to recover gallium. However, it still suffers from high reagent consumption, a lengthy operation process, and a narrow applicability, failing to effectively recover gallium from low-concentration gallium solutions.

[0006] CN 111961867A discloses a method for extracting gallium from iron-removing wastewater generated during the alumina production process from fly ash. The method includes: a raw material concentration stage: concentrating the iron-removing wastewater to a gallium ion content of 400-600 mg / L, and controlling the chloride ion concentration in the concentrate to 280-350 g / L; filtering to remove impurities and obtaining a clear liquid; a resin adsorption and elution stage: after ion exchange resin adsorption saturation, elution with dilute hydrochloric acid to obtain a first eluent; eluent concentration: concentrating the first eluent by more than one-fold; an ion reduction stage: reducing the obtained concentrate with iron powder to reduce ferric ions to ferrous ions; a resin adsorption and elution stage II to obtain a second eluent; and post-treatment: subjecting the second eluent to impurities removal, electrolysis, and refining to obtain metallic gallium. This method is still suitable for the recovery of high-concentration gallium solutions, employing a two-stage adsorption and elution process with numerous steps. Furthermore, the eluent obtained from adsorption and elution still requires neutralization and electrolysis, resulting in insufficient gallium recovery.

[0007] In summary, for the process of preparing gallium oxide from gallium-containing solutions, it is still necessary to select new conversion pathways based on the compositional characteristics of the gallium-containing solutions to achieve short-range preparation of gallium oxide from hydrated gallium products after enrichment of low-concentration gallium, thereby improving the recovery rate of low-concentration gallium and reducing the production cost of the process. Summary of the Invention

[0008] To address the problems existing in the prior art, the present invention aims to provide a method for preparing gallium oxide from a gallium-containing solution. The method enriches the gallium-containing solution through resin adsorption and rinsing, and then, through the control of composite precipitants and process conditions, performs pre-neutralization and aging crystallization operations to precipitate and separate gallium in the form of hydrated gallium products. This achieves a short-range process for enriching and separating low-concentration gallium to prepare gallium oxide, thereby reducing the production cost of gallium products.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] This invention provides a method for preparing gallium oxide from a gallium-containing solution, the method comprising the following steps:

[0011] (1) The gallium-containing solution was sequentially passed through resin adsorption and rinsing to obtain a gallium-enriched solution;

[0012] (2) The gallium enrichment solution obtained in step (1) is pre-neutralized using a composite precipitant, the composite precipitant comprising an alkali and an anion salt, to obtain a gallium-rich neutralized solution;

[0013] (3) The gallium-rich neutralized liquid obtained in step (2) is aged and crystallized, and the hydrated gallium product is obtained after separation;

[0014] (4) The hydrated gallium product obtained in step (3) is calcined to obtain gallium oxide product. The tail gas generated during calcination is absorbed and used for gallium rinsing in step (1).

[0015] In this invention, the recovery and utilization of gallium from gallium-containing solutions, especially the treatment of low-concentration gallium-containing solutions, requires prior gallium enrichment. This invention employs gallium adsorption resin for adsorption. After adsorption saturation, rinsing is performed to convert the gallium ions adsorbed by chelation in the saturated resin into soluble gallium salts that enter the liquid phase, achieving the enrichment of low-concentration gallium in solutions containing multiple impurities. The pre-enriched gallium solution is then pre-neutralized, utilizing the alkali and acid anion salts in the composite precipitant to create a weakly acidic environment. Low pH conditions are controlled, and aging promotes the extraction of gallium. The environmental conditions during the pre-neutralization and aging process in this invention can inhibit the hydrolysis and precipitation of impurity ions in the gallium enrichment solution, which helps to improve the stability of hydrated gallium products during the aging process. At the same time, the acid radical anions in the composite precipitant make it easier for gallium ions to coordinate and form stable hydrated gallium products, improve the coordination of gallium ions under acidic conditions, strengthen the aging process, and increase the hydrolysis and precipitation rate of gallium ions, thereby greatly improving the precipitation performance of low-concentration gallium and realizing the recycling of rinsing solution and precipitating mother liquor, reducing the production cost of gallium products.

[0016] This application does not use the traditional near-neutral environment with pH 4.0~7.0 to control gallium hydrolysis to generate gallium hydroxyl oxide. In the traditional hydrolysis precipitation environment, the amount of neutralizing agent used is large, the mother liquor of hydrolysis precipitation cannot be recycled, and because the concentration in the solution after low-concentration gallium enrichment is still low, the traditional hydrolysis precipitation environment is prone to gallium element gelation, resulting in low gallium element yield and poor performance of gallium hydrolysis precipitation.

[0017] In this invention, the hydrated gallium product separated after aging and crystallization mainly exists in the form of gallium hydroxysulfate hydrate. After calcination, gallium oxide is obtained, and the generated gaseous product can be used to prepare an acidic rinsing solution through tail gas absorption, thus realizing medium circulation. This process realizes the direct preparation of gallium oxide products after enrichment and separation of low-concentration gallium solutions, that is, the direct conversion of metallurgical gallium solutions into gallium oxide. The method has a simple process flow, is easy to operate, consumes less reagents, has a lower production cost, and helps to recycle low-concentration gallium solutions, making it more widely applicable.

[0018] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following technical solutions.

[0019] As a preferred technical solution of the present invention, the gallium-containing solution in step (1) includes any one or a combination of at least two of the following: gallium-containing seed mother liquor in the bauxite extraction process, gallium-containing aluminum chloride solution or gallium-containing sodium aluminate solution in the fly ash extraction process, and gallium-containing acidic aluminum chloride solution or gallium-containing sodium aluminate solution in the coal gangue extraction process. Typical but non-limiting examples of the combination include: a combination of gallium-containing seed mother liquor in the bauxite extraction process and gallium-containing sodium aluminate solution in the fly ash extraction process, a combination of gallium-containing seed mother liquor in the bauxite extraction process and gallium-containing sodium aluminate solution in the coal gangue extraction process, a combination of gallium-containing aluminum chloride solution in the fly ash extraction process and gallium-containing acidic aluminum chloride solution in the coal gangue extraction process, etc., preferably a gallium-containing seed mother liquor or gallium-containing sodium aluminate solution.

[0020] Preferably, the gallium content in the gallium-containing solution in step (1) is 20~200 mg / L, such as 20 mg / L, 50 mg / L, 80 mg / L, 100 mg / L, 120 mg / L, 150 mg / L, 180 mg / L or 200 mg / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] As a preferred technical solution of the present invention, the resin adsorption in step (1) is an acidic gallium adsorption resin or an alkaline gallium adsorption resin.

[0022] Preferably, the adsorption flow rate of the gallium-containing solution during resin adsorption in step (1) is 2.5~6 BV / h, such as 2.5 BV / h, 3 BV / h, 3.5 BV / h, 4 BV / h, 4.5 BV / h, 5 BV / h, 5.5 BV / h or 6 BV / h, but not limited to the listed values; other unlisted values ​​within this range are also applicable. The number of adsorption beds is 20~70 BV, such as 20 BV, 30 BV, 40 BV, 50 BV, 60 BV or 70 BV, but not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0023] Preferably, the rinsing in step (1) is performed by rinsing the saturated resin after gallium adsorption with an acidic rinsing solution.

[0024] Preferably, the acidic rinsing solution includes any one or a combination of at least two of hydrochloric acid, sulfuric acid, phosphoric acid, or nitric acid. Typical but non-limiting examples of such combinations include: a combination of hydrochloric acid and sulfuric acid, a combination of sulfuric acid and phosphoric acid, a combination of sulfuric acid and nitric acid, a combination of hydrochloric acid, sulfuric acid, and nitric acid, and a combination of sulfuric acid, phosphoric acid, and nitric acid.

[0025] Preferably, the concentration of the acidic rinsing solution is 0.1~3 mol / L, such as 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L or 3 mol / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] Preferably, the rinsing flow rate of the acidic rinsing solution during the rinsing in step (1) is 0.1~3 BV / h, such as 0.1 BV / h, 0.5 BV / h, 1 BV / h, 1.5 BV / h, 2 BV / h, 2.5 BV / h or 3 BV / h, but not limited to the listed values; other unlisted values ​​within this range are also applicable. The number of rinsing bed layers is 3~7 BV, such as 3 BV, 3.5 BV, 4 BV, 4.5 BV, 5 BV, 5.5 BV, 6 BV, 6.5 BV or 7 BV, but not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0027] Preferably, the gallium enrichment solution in step (1) is an acidic gallium enrichment solution, wherein the gallium concentration is 0.05~10g / L, such as 0.05g / L, 0.1g / L, 0.5g / L, 1g / L, 3g / L, 5g / L, 6g / L, 8g / L or 10g / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] In this invention, the composition and concentration of the acidic rinsing solution directly affect the composition of the gallium enrichment solution after rinsing, and have a significant impact on the subsequent pre-neutralization precipitation process. Using sulfuric acid or phosphoric acid systems is beneficial for forming gallium complexes and precipitating stable hydrated gallium products. When the concentration of the acidic rinsing solution is low, the amount of neutralizing agent required for the pre-neutralization process is small, which helps to achieve the recycling of the rinsing solution.

[0029] As a preferred technical solution of the present invention, the composite precipitant in step (2) is added in the form of a solution, which is a mixture of alkaline solution and acid radical anion salt solution.

[0030] Preferably, the alkaline solution comprises any one or a combination of at least two of sodium hydroxide solution, potassium hydroxide solution, or ammonia solution. Typical but non-limiting examples of such combinations include: a combination of sodium hydroxide solution and potassium hydroxide solution, a combination of sodium hydroxide solution and ammonia solution, a combination of sodium hydroxide solution, potassium hydroxide solution, and ammonia solution, etc.

[0031] Preferably, the anionic salt comprises any one or a combination of at least two of sodium sulfate, potassium sulfate, sodium phosphate, or potassium phosphate. Typical but non-limiting examples of such combinations include: combinations of sodium sulfate and potassium sulfate, combinations of sodium sulfate and sodium phosphate, combinations of sodium sulfate, potassium sulfate, and sodium phosphate, and combinations of sodium sulfate, potassium sulfate, sodium phosphate, and potassium phosphate.

[0032] Preferably, the molar ratio of the acid anion salt and the base in the composite precipitant in step (2) is (0.1~1):1, for example, 0.1:1, 0.3:1, 0.5:1, 0.6:1, 0.8:1 or 1:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] Preferably, the mixed solution of the composite precipitant is added continuously under stirring.

[0034] As a preferred technical solution of the present invention, the pre-neutralization temperature in step (2) is 0~75℃, for example 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, 50℃, 60℃, 70℃ or 75℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable; preferably 5~35℃.

[0035] Preferably, the pre-neutralization time in step (2) is 2 to 60 minutes, such as 2 minutes, 10 minutes, 20 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes or 60 minutes, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 30 to 60 minutes.

[0036] Preferably, the pre-neutralization in step (2) is carried out under stirring conditions.

[0037] Preferably, the stirring speed is 50~1000 rpm, such as 50 rpm, 100 rpm, 200 rpm, 250 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm, 800 rpm or 1000 rpm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 250~500 rpm.

[0038] Preferably, the pH value of the gallium-rich neutralizing solution after pre-neutralization in step (2) is 1.5 to 3.0, such as 1.5, 1.8, 2.0, 2.2, 2.5, 2.7 or 3.0, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] As a preferred technical solution of the present invention, the pH value is controlled at 1.5~3.0 during the aging and crystallization process in step (3), for example, 1.5, 1.8, 2.0, 2.2, 2.5, 2.7 or 3.0, but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] Preferably, the aging and crystallization temperature in step (3) is 70~150℃, such as 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 70~95℃.

[0041] Preferably, the aging and crystallization in step (3) is carried out under stirring conditions.

[0042] Preferably, the stirring speed is 5~500 rpm, such as 5 rpm, 10 rpm, 25 rpm, 50 rpm, 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 400 rpm or 500 rpm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 5~250 rpm.

[0043] Preferably, the aging and crystallization time in step (3) is 2 to 24 hours, such as 2 hours, 4 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours or 24 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0044] As a preferred technical solution of the present invention, the separation in step (3) includes solid-liquid separation, preferably filtration or centrifugal separation.

[0045] Preferably, the crystallization mother liquor obtained in step (3) is used to prepare an acidic rinsing solution to achieve media circulation.

[0046] Preferably, the hydrated gallium product in step (3) includes gallium hydroxysulfate hydrate and / or gallium hydroxyphosphate hydrate.

[0047] In this invention, the hydrated gallium product is different from the traditional gallium oxide or gallium hydroxide precipitation. The hydrated gallium product is coordinated by hydroxyl and acid radical anions to form a layered gallium octahedral coordination structure, which precipitates in a weakly acidic system.

[0048] As a preferred technical solution of the present invention, the calcination temperature in step (4) is 700~950℃, such as 700℃, 750℃, 800℃, 850℃, 900℃ or 950℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 850~950℃.

[0049] Preferably, the heating rate of the calcination in step (4) is 3~10℃ / min, such as 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min or 10℃ / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0050] Preferably, the calcination time in step (4) is 2 to 4 hours, such as 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0051] Preferably, the cooling method after calcination in step (4) is natural cooling.

[0052] Preferably, the gallium oxide product in step (4) is β-gallium oxide, the formation of which is related to the calcination temperature, and is the most common and stable phase in the gallium oxide crystal phase.

[0053] As a preferred technical solution of the present invention, the tail gas generated by calcination in step (4) is absorbed by water to obtain tail gas absorption liquid.

[0054] Preferably, the exhaust gas comprises any one or at least two combinations of SO2, SO3, or P2O5. Typical but non-limiting examples of such combinations include: combinations of SO2 and SO3, combinations of SO3 and P2O5, combinations of SO2, SO3, and P2O5, etc.

[0055] Preferably, the exhaust gas absorption liquid is an acidic solution, which is returned to step (1) as the rinsing liquid after resin adsorption.

[0056] As a preferred technical solution of the present invention, the method includes the following steps:

[0057] (1) The gallium-containing solution is sequentially subjected to resin adsorption and rinsing. The gallium content in the gallium-containing solution is 20~50 mg / L. The resin adsorption is performed using acidic gallium adsorption resin or alkaline gallium adsorption resin. The adsorption flow rate of the gallium-containing solution during resin adsorption is 2.5~6 BV / h, and the number of adsorption beds is 20~70 BV. The rinsing is performed using an acidic rinsing solution to rinse the saturated resin after gallium adsorption. The acidic rinsing solution includes any one or at least two of hydrochloric acid, sulfuric acid, phosphoric acid or nitric acid, with a concentration of 0.1~3 mol / L. The rinsing flow rate of the acidic rinsing solution during rinsing is 0.1~3 BV / h, and the number of rinsing beds is 3~7 BV, to obtain a gallium acid enrichment solution with a gallium concentration of 0.05~10 g / L.

[0058] (2) The gallium enrichment solution obtained in step (1) is pre-neutralized using a composite precipitant. The composite precipitant consists of an alkali and an acid radical anion salt, which is added in solution form. It is a mixed solution of alkali and acid radical anion salt solution. The alkali solution includes any one or at least two of sodium hydroxide solution, potassium hydroxide solution, or ammonia water. The acid radical anion salt includes any one or at least two of sodium sulfate, potassium sulfate, sodium phosphate, or potassium phosphate. The molar ratio of acid radical anion salt to alkali in the composite precipitant is (0.1~1):1. The mixed solution is added continuously under stirring. The pre-neutralization temperature is 0~75℃, the time is 2~60min, and the pre-neutralization is carried out under stirring conditions. The stirring speed is 50~1000rpm to obtain a gallium-rich neutralized solution with a pH value of 1.5~3.0.

[0059] (3) The gallium-rich neutral solution obtained in step (2) is aged and crystallized. The aging and crystallization temperature is 70~150℃, the pH value is controlled at 1.5~3.0 during the aging and crystallization process, and the process is carried out under stirring conditions. The stirring speed is 5~500rpm, and the aging and crystallization time is 2~24h. After solid-liquid separation, hydrated gallium products and crystallization mother liquor are obtained. The hydrated gallium products include gallium hydroxysulfate hydrate and / or gallium hydroxyphosphate hydrate. The crystallization mother liquor is used to prepare acidic rinsing solution.

[0060] (4) The hydrated gallium product obtained in step (3) is calcined at a temperature of 700~950℃, a heating rate of 3~10℃ / min, and a calcination time of 2~4h. After cooling, gallium oxide product is obtained. The gallium oxide product is β-gallium oxide. The tail gas generated by calcination is absorbed by water to obtain tail gas absorbent. The tail gas composition includes any one or at least two combinations of SO2, SO3 or P2O5. The tail gas absorbent is an acidic solution used for rinsing gallium after resin adsorption in step (1).

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] (1) The method of the present invention enriches the gallium-containing solution by resin adsorption and rinsing, and then, by controlling the process conditions such as composite precipitant and low pH, the gallium is precipitated and separated in the form of hydrated gallium products through pre-neutralization and aging crystallization. The amount of composite precipitant used is small and the gallium recovery rate is high, which can reach more than 95%.

[0063] (2) The composite precipitant used in the method of the present invention can promote the occurrence of gallium ion coordination hydrolysis reaction, which is conducive to the generation of layered hydrated gallium products with hydroxyl groups and oxyacid anions co-coordinated, thereby improving the stability of gallium products. After calcination and decomposition, the tail gas is absorbed and recycled in the gallium adsorption rinsing process, realizing the recycling of the medium and reducing the cost of neutralization precipitation.

[0064] (3) The method described in this invention realizes the process of directly preparing gallium oxide products after enrichment and separation of low-concentration gallium solution, that is, realizing the direct conversion of metallurgical gallium solution into gallium oxide;

[0065] (4) The method described in this invention has a simple process flow, is easy to operate, consumes less reagents, has a lower production cost, and is more widely applicable. Attached Figure Description

[0066] Figure 1 This is a process flow diagram of the method for preparing gallium oxide from a gallium-containing solution provided in Embodiment 1 of the present invention. Detailed Implementation

[0067] To better illustrate the present invention and facilitate understanding of its technical solutions, the present invention is further described in detail below. However, the following embodiments are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0068] The following are typical but non-limiting embodiments of the present invention:

[0069] Example 1:

[0070] This embodiment provides a method for preparing gallium oxide from a gallium-containing solution, and the process flow diagram of the method is shown below. Figure 1 As shown, it includes the following steps:

[0071] (1) The gallium-containing solution is subjected to resin adsorption and rinsing in sequence. The gallium-containing solution is the gallium-containing mother liquor in the bauxite extraction process, wherein the gallium content is 50 mg / L. The resin adsorption is carried out using alkaline gallium adsorption resin. The adsorption flow rate of the gallium-containing solution during resin adsorption is 2.5 BV / h, and the number of adsorption beds is 70 BV. The rinsing is carried out using acidic rinsing solution to rinse the saturated resin after gallium adsorption. The acidic rinsing solution is sulfuric acid with a concentration of 0.1 mol / L. The rinsing flow rate of the acidic rinsing solution during rinsing is 1 BV / h, and the number of rinsing beds is 6 BV, to obtain gallium sulfate acid enrichment solution with a gallium concentration of 1.5 g / L.

[0072] (2) The gallium enrichment solution obtained in step (1) is pre-neutralized using a composite precipitant, wherein the composite precipitant is a mixed solution of sodium sulfate and sodium hydroxide with a molar ratio of 0.1:1. The mixed solution is added continuously under stirring. The pre-neutralization temperature is 5°C and the time is 20 min. The pre-neutralization is carried out under stirring conditions, and the stirring speed is 500 rpm, to obtain a gallium-rich neutralized solution with a pH value of 3.0.

[0073] (3) The gallium-rich neutralized solution obtained in step (2) is aged and crystallized at a temperature of 70°C. The pH value is controlled at 3.0 during the aging and crystallization process. The process is carried out under stirring conditions, with a stirring speed of 5 rpm and an aging and crystallization time of 2 hours. After filtration and separation, hydrated gallium products and crystallization mother liquor are obtained. The hydrated gallium products include gallium hydroxysulfate hydrate. The crystallization mother liquor is used to prepare an acidic rinsing solution.

[0074] (4) The hydrated gallium product obtained in step (3) is calcined at a temperature of 800°C, a heating rate of 5°C / min, and a calcination time of 2h. After cooling, gallium oxide product is obtained. The gallium oxide product is β-gallium oxide. The tail gas generated by calcination is absorbed by water to obtain tail gas absorption liquid. The tail gas consists of SO2 and SO3. The tail gas absorption liquid is an acidic solution used for rinsing gallium after resin adsorption in step (1).

[0075] The concentration of gallium in the solution at each step was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The gallium recovery rate was calculated based on the concentration and volume of gallium in the gallium acid enrichment solution and the concentration and volume of gallium in the crystallization mother liquor.

[0076] In this embodiment, the gallium-containing solution was treated using the above method, and the gallium recovery rate was calculated to be 99.12%.

[0077] Example 2:

[0078] This embodiment provides a method for preparing gallium oxide from a gallium-containing solution, the method comprising the following steps:

[0079] (1) The gallium-containing solution is subjected to resin adsorption and rinsing in sequence. The gallium-containing solution is a gallium-containing acidic aluminum chloride solution from the coal gangue extraction process, wherein the gallium content is 100 mg / L. The resin adsorption is performed using acidic gallium adsorption resin. The adsorption flow rate of the gallium-containing solution during resin adsorption is 6 BV / h, and the number of adsorption beds is 20 BV. The rinsing is performed using an acidic rinsing solution to rinse the saturated resin after gallium adsorption. The acidic rinsing solution is phosphoric acid with a concentration of 0.3 mol / L. The rinsing flow rate of the acidic rinsing solution during rinsing is 0.1 BV / h, and the number of rinsing beds is 3 BV, to obtain a gallium phosphate acid enrichment solution with a gallium concentration of 0.5 g / L.

[0080] (2) The gallium enrichment solution obtained in step (1) is pre-neutralized using a composite precipitant, wherein the composite precipitant is a mixed solution of sodium phosphate and ammonia water with a molar ratio of 1:1. The mixed solution is added continuously under stirring. The pre-neutralization temperature is 75°C and the time is 60 min. The pre-neutralization is carried out under stirring conditions, and the stirring speed is 1000 rpm. A gallium-rich neutralized solution with a pH value of 1.5 is obtained.

[0081] (3) The gallium-rich neutral solution obtained in step (2) is aged and crystallized at a temperature of 150°C. The pH value is controlled at 1.5 during the aging and crystallization process. The process is carried out under stirring conditions at a speed of 250 rpm and a aging and crystallization time of 24 h. After filtration and separation, hydrated gallium products and crystallization mother liquor are obtained. The hydrated gallium products include gallium hydroxyphosphate hydrate. The crystallization mother liquor is used to prepare an acidic rinsing solution.

[0082] (4) The hydrated gallium product obtained in step (3) is calcined at a temperature of 950°C, a heating rate of 3°C / min, and a calcination time of 4h. After cooling, gallium oxide product is obtained. The gallium oxide product is β-gallium oxide. The tail gas generated by calcination is absorbed by water to obtain tail gas absorption liquid. The tail gas composition includes P2O5. The tail gas absorption liquid is an acidic solution used for rinsing gallium after resin adsorption in step (1).

[0083] The test method described is the same as that in Example 1.

[0084] In this embodiment, the gallium-containing solution was treated using the above method, and the gallium recovery rate was calculated to be 95.06%.

[0085] Example 3:

[0086] This embodiment provides a method for preparing gallium oxide from a gallium-containing solution, the method comprising the following steps:

[0087] (1) The gallium-containing solution is subjected to resin adsorption and rinsing in sequence. The gallium-containing solution is a sodium gallium aluminate solution from the fly ash extraction process, wherein the gallium content is 200 mg / L. The resin adsorption is performed using an alkaline gallium adsorption resin. The adsorption flow rate of the gallium-containing solution during resin adsorption is 4 BV / h, and the number of adsorption beds is 50 BV. The rinsing is performed using an acidic rinsing solution to rinse the saturated resin after gallium adsorption. The acidic rinsing solution is hydrochloric acid with a concentration of 3 mol / L. The rinsing flow rate of the acidic rinsing solution during rinsing is 3 BV / h, and the number of rinsing beds is 7 BV, to obtain an acidic gallium chloride enrichment solution with a gallium concentration of 10 g / L.

[0088] (2) The gallium enrichment solution obtained in step (1) is pre-neutralized using a composite precipitant, wherein the composite precipitant is a mixed solution of sodium sulfate and sodium hydroxide with a molar ratio of 0.5:1. The mixed solution is added continuously under stirring. The pre-neutralization temperature is 0°C and the time is 2 min. The pre-neutralization is carried out under stirring conditions with a stirring speed of 50 rpm to obtain a gallium-rich neutralized solution with a pH value of 2.7.

[0089] (3) The gallium-rich neutralized solution obtained in step (2) is aged and crystallized at a temperature of 90°C. The pH value is controlled at 2.7 during the aging and crystallization process. The process is carried out under stirring conditions, with a stirring speed of 500 rpm and an aging and crystallization time of 12 h. After filtration and separation, hydrated gallium products and crystallization mother liquor are obtained. The hydrated gallium products include gallium hydroxysulfate hydrate. The crystallization mother liquor is used to prepare an acidic rinsing solution.

[0090] (4) The hydrated gallium product obtained in step (3) is calcined at a temperature of 700°C, a heating rate of 10°C / min, and a calcination time of 3h. After cooling, gallium oxide product is obtained. The gallium oxide product is β-gallium oxide. The tail gas generated by calcination is absorbed by water to obtain tail gas absorption liquid. The tail gas composition includes SO2. The tail gas absorption liquid is an acidic solution used for rinsing gallium after resin adsorption in step (1).

[0091] The test method described is the same as that in Example 1.

[0092] In this embodiment, the gallium-containing solution was treated using the above method, and the calculated gallium recovery rate reached 97.44%.

[0093] Example 4:

[0094] This embodiment provides a method for preparing gallium oxide from a gallium-containing solution, the method comprising the following steps:

[0095] (1) The gallium-containing solution is subjected to resin adsorption and rinsing in sequence. The gallium-containing solution is a gallium-containing aluminum chloride solution from the fly ash extraction process, wherein the gallium content is 80 mg / L. The resin adsorption is performed using acidic gallium adsorption resin. The adsorption flow rate of the gallium-containing solution during resin adsorption is 5 BV / h, and the number of adsorption beds is 60 BV. The rinsing is performed using acidic rinsing solution to rinse the saturated resin after gallium adsorption. The acidic rinsing solution is nitric acid with a concentration of 2 mol / L. The rinsing flow rate of the acidic rinsing solution during rinsing is 2.5 BV / h, and the number of rinsing beds is 6.5 BV, to obtain gallium nitrate acid enrichment solution with a gallium concentration of 5 g / L.

[0096] (2) The gallium enrichment solution obtained in step (1) is pre-neutralized using a composite precipitant, wherein the composite precipitant is a mixed solution of sodium phosphate and sodium hydroxide with a molar ratio of 0.3:1. The mixed solution is added continuously under stirring. The pre-neutralization temperature is 50°C and the time is 30 min. The pre-neutralization is carried out under stirring conditions, and the stirring speed is 400 rpm. A gallium-rich neutralized solution with a pH value of 2.5 is obtained.

[0097] (3) The gallium-rich neutral solution obtained in step (2) is aged and crystallized at a temperature of 120°C. The pH value is controlled at 2.5 during the aging and crystallization process. The process is carried out under stirring conditions at a speed of 100 rpm and a aging and crystallization time of 6 hours. After filtration and separation, hydrated gallium products and crystallization mother liquor are obtained. The hydrated gallium products include gallium hydroxyphosphate hydrate. The crystallization mother liquor is used to prepare an acidic rinsing solution.

[0098] (4) The hydrated gallium product obtained in step (3) is calcined at a temperature of 850°C, a heating rate of 6°C / min, and a calcination time of 3.5h. After cooling, gallium oxide product is obtained. The gallium oxide product is β-gallium oxide. The tail gas generated by calcination is absorbed by water to obtain tail gas absorbent. The tail gas composition includes P2O5. The tail gas absorbent is an acidic solution used for rinsing gallium after resin adsorption in step (1).

[0099] The test method described is the same as that in Example 1.

[0100] In this embodiment, the gallium-containing solution was treated using the above method, and the gallium recovery rate was calculated to be 98.27%.

[0101] Example 5:

[0102] This embodiment provides a method for preparing gallium oxide from a gallium-containing solution, the method comprising the following steps:

[0103] (1) The gallium-containing solution is subjected to resin adsorption and rinsing in sequence. The gallium-containing solution is a sodium aluminate solution containing gallium from the coal gangue extraction process, wherein the gallium content is 30 mg / L. The resin adsorption is performed using an alkaline gallium adsorption resin. The adsorption flow rate of the gallium-containing solution during resin adsorption is 3 BV / h, and the number of adsorption beds is 40 BV. The rinsing is performed using an acidic rinsing solution to rinse the saturated resin after gallium adsorption. The acidic rinsing solution is sulfuric acid with a concentration of 0.5 mol / L. The rinsing flow rate of the acidic rinsing solution during rinsing is 0.5 BV / h, and the number of rinsing beds is 5 BV, to obtain an acidic gallium sulfate enrichment solution with a gallium concentration of 0.5 g / L.

[0104] (2) The gallium enrichment solution obtained in step (1) is pre-neutralized using a composite precipitant, wherein the composite precipitant is a mixed solution of sodium sulfate and ammonia water with a molar ratio of 0.2:1. The mixed solution is added continuously under stirring. The pre-neutralization temperature is 25°C and the time is 45 min. The pre-neutralization is carried out under stirring conditions with a stirring speed of 100 rpm to obtain a gallium-rich neutralized solution with a pH value of 2.0.

[0105] (3) The gallium-rich neutralized solution obtained in step (2) is aged and crystallized at a temperature of 100°C. The pH value is controlled at 2.0 during the aging and crystallization process. The process is carried out under stirring conditions at a speed of 250 rpm and a aging and crystallization time of 16 h. After filtration and separation, hydrated gallium products and crystallization mother liquor are obtained. The hydrated gallium products include gallium hydroxysulfate hydrate. The crystallization mother liquor is used to prepare an acidic rinsing solution.

[0106] (4) The hydrated gallium product obtained in step (3) is calcined at a temperature of 900°C, a heating rate of 8°C / min, and a calcination time of 2.5h. After cooling, gallium oxide product is obtained. The gallium oxide product is β-gallium oxide. The tail gas generated by calcination is absorbed by water to obtain tail gas absorption liquid. The tail gas consists of SO2 and SO3. The tail gas absorption liquid is an acidic solution used for rinsing gallium after resin adsorption in step (1).

[0107] The test method described is the same as that in Example 1.

[0108] In this embodiment, the gallium-containing solution was treated using the above method, and the calculated gallium recovery rate reached 97.85%.

[0109] Comparative Example 1:

[0110] This comparative example provides a method for preparing gallium oxide from a gallium-containing solution. The method is the same as that in Example 1, except that a composite precipitant is not used in step (2), but only sodium hydroxide is used.

[0111] In this comparative example, since sodium hydroxide was used as the precipitant, the gallium hydroxyl oxide obtained by alkaline hydrolysis under this pH condition had an amorphous structure and an unstable crystal structure, which was not conducive to the precipitation reaction of gallium, resulting in a low gallium recovery rate of only 85.32%.

[0112] Comparative Example 2:

[0113] This comparative example provides a method for preparing gallium oxide from a gallium-containing solution. The method is the same as that in Example 1, except that the aging and crystallization in step (3) is not included.

[0114] In this comparative example, since the gallium enrichment solution was not aged after pre-neutralization, only small crystal nuclei of hydrated gallium products were generated. These nuclei had poor stability and could not grow into large crystal nuclei, resulting in a significant reduction in gallium recovery rate to only 15.32%.

[0115] As can be seen from the above embodiments and comparative examples, the method of the present invention enriches the gallium-containing solution through resin adsorption and rinsing. Then, through the control of process conditions such as composite precipitant and low pH, and after pre-neutralization and aging crystallization, gallium is precipitated and separated in the form of hydrated gallium products. The amount of composite precipitant used is small, and the gallium recovery rate is high, reaching over 95%. The composite precipitant used in the method promotes the coordination hydrolysis reaction of gallium ions, which is beneficial for the hydrolysis to generate layered hydrated gallium products with hydroxyl groups and oxyanions co-coordinated, improving the stability of the gallium products. After calcination and decomposition, the tail gas is absorbed and recycled in the gallium adsorption rinsing process, realizing the recycling of the medium and reducing the cost of neutralization and precipitation. The method realizes the direct preparation of gallium oxide products after enrichment and separation of low-concentration gallium solutions, that is, the direct conversion of metallurgical gallium solutions into gallium oxide. The method has a simple process flow, is easy to operate, consumes few reagents, has low production costs, and has a wider range of applications.

[0116] The applicant declares that the present invention is illustrated through the above embodiments, but the present invention is not limited to the above detailed methods, that is, it does not mean that the present invention must rely on the above detailed methods to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the methods of the present invention, additions of auxiliary steps, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing gallium oxide from a gallium-containing solution, characterized in that, The method includes the following steps: (1) The gallium-containing solution was sequentially passed through resin adsorption and rinsing to obtain a gallium-enriched solution; (2) The gallium enrichment solution obtained in step (1) is pre-neutralized using a composite precipitant, the composite precipitant comprising an alkali and an anion salt, to obtain a gallium-rich neutralized solution; (3) The gallium-rich neutralized liquid obtained in step (2) is aged and crystallized, and the hydrated gallium product is obtained after separation; (4) The hydrated gallium product obtained in step (3) is calcined to obtain gallium oxide product. The tail gas generated during calcination is absorbed and used for gallium rinsing in step (1). The composite precipitant in step (2) is added in the form of a solution, which is a mixture of alkaline solution and acid anion salt solution; The alkaline solution includes any one or a combination of at least two of sodium hydroxide solution, potassium hydroxide solution, or ammonia water. The anionic salt of the acid radical includes any one or a combination of at least two of sodium sulfate, potassium sulfate, sodium phosphate, or potassium phosphate. The pH value of the gallium-rich neutralizing solution after pre-neutralization in step (2) is 1.5~3.

0.

2. The method according to claim 1, characterized in that, The gallium-containing solution in step (1) includes any one or a combination of at least two of the following: gallium-containing seed mother liquor in the bauxite extraction process, gallium-containing aluminum chloride solution or gallium-containing sodium aluminate solution in the fly ash extraction process, and gallium-containing acidic aluminum chloride solution or gallium-containing sodium aluminate solution in the coal gangue extraction process.

3. The method according to claim 2, characterized in that, The gallium-containing solution in step (1) is a gallium-containing seed mother liquor or a gallium-containing sodium aluminate solution.

4. The method according to claim 1, characterized in that, The gallium content in the gallium-containing solution in step (1) is 20~200 mg / L.

5. The method according to claim 1, characterized in that, The resin adsorption in step (1) uses either acidic gallium adsorption resin or basic gallium adsorption resin.

6. The method according to claim 1, characterized in that, In step (1), the adsorption flow rate of the gallium-containing solution during resin adsorption is 2.5~6 BV / h.

7. The method according to claim 1, characterized in that, The rinsing in step (1) involves rinsing the saturated resin after gallium adsorption with an acidic rinsing solution.

8. The method according to claim 7, characterized in that, The acidic rinsing solution includes any one or a combination of at least two of hydrochloric acid, sulfuric acid, phosphoric acid, or nitric acid.

9. The method according to claim 7, characterized in that, The concentration of the acidic rinsing solution is 0.1~3 mol / L.

10. The method according to claim 7, characterized in that, In step (1), the rinsing flow rate of the acidic rinsing solution is 0.1~3 BV / h.

11. The method according to claim 1, characterized in that, The gallium enrichment solution in step (1) is an acidic gallium enrichment solution with a gallium concentration of 0.05~10g / L.

12. The method according to claim 1, characterized in that, In step (2), the molar ratio of acid anion salt to base in the composite precipitant is (0.1~1):

1.

13. The method according to claim 1, characterized in that, The composite precipitant solution is added continuously under stirring.

14. The method according to claim 1, characterized in that, The pre-neutralization temperature in step (2) is 0~75℃.

15. The method according to claim 14, characterized in that, The pre-neutralization temperature in step (2) is 5~35℃.

16. The method according to claim 1, characterized in that, The pre-neutralization time in step (2) is 2 to 60 minutes.

17. The method according to claim 16, characterized in that, The pre-neutralization time in step (2) is 30~60 minutes.

18. The method according to claim 1, characterized in that, The pre-neutralization in step (2) is carried out under stirring conditions.

19. The method according to claim 18, characterized in that, The stirring speed is 50~1000 rpm.

20. The method according to claim 19, characterized in that, The stirring speed is 250~500 rpm.

21. The method according to claim 1, characterized in that, In step (3), the pH value is controlled at 1.5~3.0 during the aging and crystallization process.

22. The method according to claim 1, characterized in that, The aging and crystallization temperature in step (3) is 70~150℃.

23. The method according to claim 22, characterized in that, The aging and crystallization temperature in step (3) is 70~95℃.

24. The method according to claim 1, characterized in that, The aging and crystallization in step (3) is carried out under stirring conditions.

25. The method according to claim 24, characterized in that, The stirring speed is 5~500 rpm.

26. The method according to claim 25, characterized in that, The stirring speed is 5~250 rpm.

27. The method according to claim 1, characterized in that, The aging and crystallization time in step (3) is 2~24h.

28. The method according to claim 1, characterized in that, The separation in step (3) includes solid-liquid separation.

29. The method according to claim 28, characterized in that, The separation in step (3) is either filtration or centrifugal separation.

30. The method according to claim 1, characterized in that, The crystallization mother liquor obtained in step (3) is used to prepare acidic rinsing solution.

31. The method according to claim 1, characterized in that, The hydrated gallium product in step (3) includes gallium hydroxysulfate hydrate and / or gallium hydroxyphosphate hydrate.

32. The method according to claim 1, characterized in that, The calcination temperature in step (4) is 700~950℃.

33. The method according to claim 32, characterized in that, The calcination temperature in step (4) is 850~950℃.

34. The method according to claim 1, characterized in that, The heating rate of the calcination in step (4) is 3~10℃ / min.

35. The method according to claim 1, characterized in that, The calcination time in step (4) is 2-4 hours.

36. The method according to claim 1, characterized in that, The cooling method after calcination in step (4) is natural cooling.

37. The method according to claim 1, characterized in that, The gallium oxide product mentioned in step (4) is β-gallium oxide.

38. The method according to claim 1, characterized in that, The tail gas generated by calcination in step (4) is absorbed by water to obtain tail gas absorption liquid.

39. The method according to claim 38, characterized in that, The exhaust gas consists of any one or at least two of SO2, SO3, or P2O5.

40. The method according to claim 38, characterized in that, The exhaust gas absorption liquid is an acidic solution, which is returned to step (1) as the rinsing liquid after resin adsorption.

41. The method according to claim 1, characterized in that, The method includes the following steps: (1) The gallium-containing solution is sequentially subjected to resin adsorption and rinsing. The gallium content in the gallium-containing solution is 20~200 mg / L. The resin adsorption is performed using acidic gallium adsorption resin or alkaline gallium adsorption resin. The adsorption flow rate of the gallium-containing solution during resin adsorption is 2.5~6 BV / h. The rinsing is performed using an acidic rinsing solution to rinse the saturated resin after gallium adsorption. The acidic rinsing solution includes any one or a combination of at least two of hydrochloric acid, sulfuric acid, phosphoric acid or nitric acid, with a concentration of 0.1~3 mol / L. The rinsing flow rate of the acidic rinsing solution during rinsing is 0.1~3 BV / h, resulting in a gallium acid enrichment solution with a gallium concentration of 0.05~10 g / L. (2) The gallium enrichment solution obtained in step (1) is pre-neutralized using a composite precipitant. The composite precipitant consists of an alkali and an acid radical anion salt, which is added in solution form. It is a mixed solution of alkali and acid radical anion salt. The alkali includes any one or at least two of sodium hydroxide solution, potassium hydroxide solution, or ammonia water. The acid radical anion salt includes any one or at least two of sodium sulfate, potassium sulfate, sodium phosphate, or potassium phosphate. The molar ratio of acid radical anion salt to alkali in the composite precipitant is (0.1~1):

1. The mixed solution is added continuously under stirring. The pre-neutralization temperature is 0~75℃, the time is 2~60min, and the pre-neutralization is carried out under stirring conditions. The stirring speed is 50~1000rpm to obtain a gallium-rich neutralized solution with a pH value of 1.5~3.

0. (3) The gallium-rich neutral solution obtained in step (2) is aged and crystallized. The aging and crystallization temperature is 70~150℃, the pH value is controlled at 1.5~3.0 during the aging and crystallization process, and the process is carried out under stirring conditions. The stirring speed is 5~500rpm, and the aging and crystallization time is 2~24h. After solid-liquid separation, hydrated gallium products and crystallization mother liquor are obtained. The hydrated gallium products include gallium hydroxysulfate hydrate and / or gallium hydroxyphosphate hydrate. The crystallization mother liquor is used to prepare acidic rinsing solution. (4) The hydrated gallium product obtained in step (3) is calcined at a temperature of 700~950℃, a heating rate of 3~10℃ / min, and a calcination time of 2~4h. After cooling, gallium oxide product is obtained. The gallium oxide product is β-gallium oxide. The tail gas generated by calcination is absorbed by water to obtain tail gas absorbent. The tail gas composition includes any one or at least two combinations of SO2, SO3 or P2O5. The tail gas absorbent is an acidic solution used for rinsing gallium after resin adsorption in step (1).

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