Method for comprehensive recovery of alumina and gallium from bauxite

Abstract

The present application belongs to the technical field of comprehensive utilization of bauxite resources, and provides a method for comprehensive recovery of alumina and gallium in bauxite. The method comprises the following steps: decomposing sodium aluminate solution generated in the production process of Bayer alumina to obtain a gallium-rich mother liquor, detecting the impurity content in the mother liquor, and selecting different gallium enrichment and separation methods according to the impurity content; when the impurity content in the mother liquor is less than or equal to 1 g / L, adopting amidoxime chelating resin adsorption and desorption; when the impurity content in the mother liquor is greater than 1 g / L, adopting solvent extraction and back extraction to obtain a gallium-rich liquid; and then obtaining metallic gallium through evaporation concentration and electrolytic refining, and obtaining alumina through calcination of the aluminum hydroxide generated in the decomposition. The present application can realize efficient enrichment and recovery of gallium in the gallium-rich mother liquor, improve the gallium recovery efficiency and product purity, and is stable in process flow and suitable for resource comprehensive utilization in the alumina production system.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization technology of bauxite resources, and in particular to a comprehensive recovery method of alumina and gallium from bauxite. Background Technology

[0002] Bauxite is the main raw material for alumina production and also an important associated resource of gallium. Gallium is usually found in trace amounts in bauxite. During the Bayer process of alumina production, some gallium enters the liquid phase with the sodium aluminate solution and gradually accumulates in the mother liquor during decomposition. Therefore, recovering gallium from the gallium-containing mother liquor generated during alumina production is of great significance for improving resource utilization efficiency and increasing the added value of bauxite.

[0003] Currently, the main goal of treating gallium-containing mother liquor is to enrich and separate gallium. However, in actual production, due to different ore sources, the composition and content of impurities fluctuate significantly. For example, unstable changes in the content of impurities such as iron, silicon, copper, vanadium, and organic carbon often affect the subsequent gallium separation process. At the same time, the mother liquor system is usually characterized by high alkalinity and high salinity, making the separation process conditions complex and placing higher demands on process stability.

[0004] Under current technological conditions, there is often a lack of unified and stable treatment strategies for gallium-containing mother liquors with different compositional characteristics. This makes it difficult to simultaneously achieve gallium enrichment efficiency, product purity, and process stability during actual operation. When the composition of the mother liquor fluctuates, existing processes are prone to problems such as unstable treatment effects, increased gallium loss, or increased operating costs, thereby restricting the efficient recovery and utilization of gallium resources.

[0005] Therefore, there is an urgent need to develop a comprehensive method for the recovery of alumina and gallium from bauxite that can adapt to different mother liquor system conditions, improve gallium recovery efficiency, and take into account process stability. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problems of "disconnection between alumina production and gallium recovery, poor adaptability, and low total gallium recovery rate" in existing bauxite recovery technologies. This invention provides a comprehensive method for the recovery of alumina and gallium from bauxite, achieving a total gallium recovery rate of ≥95% and a product purity of ≥99.98%, while ensuring the quality of alumina products.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a comprehensive method for recovering alumina and gallium from bauxite, comprising the following steps:

[0009] S1. The sodium aluminate solution obtained from the leaching of bauxite is decomposed, and the decomposed slurry is subjected to solid-liquid separation to obtain aluminum hydroxide precipitate and gallium-rich mother liquor.

[0010] S2. Perform impurity analysis on gallium-rich mother liquor. When the total impurity content in gallium-rich mother liquor is ≤1g / L, use adsorption resin to adsorb and enrich gallium in the mother liquor to obtain gallium-loaded adsorption resin. When the total impurity content in the gallium-rich mother liquor is >1 g / L, a solvent extraction system is used to extract gallium from the mother liquor to obtain a gallium-containing solvent extract phase.

[0011] S3. Desorb the gallium-loaded adsorption resin or back-extract the gallium-containing solvent extraction phase to obtain a gallium-rich solution;

[0012] S4. The gallium-rich solution is evaporated, concentrated, and electrolytically refined to obtain metallic gallium;

[0013] S5. The aluminum hydroxide precipitate is calcined to obtain aluminum oxide.

[0014] Preferably, the gallium concentration in the gallium-rich mother liquor in step S1 is 0.8~1.5 g / L.

[0015] Preferably, the adsorption resin in step S2 is a chelating resin for amine oxime.

[0016] Preferably, the adsorption in step S2 is carried out at a pH of 13-14 and a temperature of 40-50°C in a resin adsorption column with an empty column flow rate of 1-2 BV / h and an adsorption time of 50-80 min.

[0017] Preferably, the solvent extraction system in step S2 comprises the following volume fractions of components:

[0018] 15-20% di(2-ethylhexyl)phosphoric acid, 0-5% tributyl phosphate, balance sulfonated kerosene.

[0019] Preferably, the extraction temperature in step S2 is 20~30℃, the extraction time is 10~20min, and the volume ratio of the solvent extraction system to the gallium-rich mother liquor during the extraction process is 1:2~4.

[0020] Preferably, in step S3, sulfuric acid solution is used as the desorbent; the concentration of the sulfuric acid solution is 0.5~1 mol / L; the desorption flow rate is 0.5~1 BV / h; the desorption temperature is 20~40℃; and the desorption time is 20~60 min.

[0021] Preferably, the stripping agent in step S3 is a hydrochloric acid solution and / or a sodium chloride solution, the stripping temperature is 30~32℃, the stripping time is 10~12min, and the volume ratio of the gallium-containing solvent extractant to the stripping agent during the stripping process is 4~5:1.

[0022] Preferably, the evaporation and concentration temperature in step S4 is 120~150℃, and the evaporation and concentration is carried out until the gallium concentration in the gallium-rich solution is ≥50g / L;

[0023] The current density of the electrolytic refining is 100~150A / m², and the temperature of the electrolytic refining is 30~40℃.

[0024] Preferably, the calcination temperature in step S5 is 950~1200℃, and the calcination time is 3~8s.

[0025] The beneficial effects of this invention include the following:

[0026] 1) This invention targets gallium-rich mother liquor generated during the Bayer process of alumina production. By detecting the impurity content of the mother liquor and selecting different gallium enrichment and separation methods, gallium can be efficiently recovered, thereby improving the overall gallium recovery efficiency.

[0027] 2) This invention enriches gallium in gallium-rich mother liquor by resin adsorption or solvent extraction, and combines desorption or back-extraction, evaporation concentration and electrolytic refining to obtain metallic gallium products with a purity of ≥99.98%, while ensuring the stable operation of the alumina production process.

[0028] 3) Based on the different impurity contents in the gallium-rich mother liquor, the present invention selects adsorption or solvent extraction methods for gallium enrichment, so that the process can adapt to mother liquor systems with different compositions and impurity levels, thereby improving the stability and adaptability of the gallium recovery process.

[0029] 4) The adsorption, solvent extraction, and electrolytic refining processes used in this invention are all mature industrial unit operations with strong equipment versatility, stable process flow, and easy implementation in existing alumina production systems. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the process flow for a comprehensive recovery method of alumina and gallium from bauxite according to the present invention. Detailed Implementation

[0031] This invention provides a comprehensive method for recovering alumina and gallium from bauxite, comprising the following steps:

[0032] S1. The sodium aluminate solution obtained from the leaching of bauxite is decomposed, and the decomposed slurry is subjected to solid-liquid separation to obtain aluminum hydroxide precipitate and gallium-rich mother liquor.

[0033] S2. Perform impurity analysis on gallium-rich mother liquor. When the total impurity content in gallium-rich mother liquor is ≤1g / L, use adsorption resin to adsorb and enrich gallium in the mother liquor to obtain gallium-loaded adsorption resin. When the total impurity content in the gallium-rich mother liquor is >1 g / L, a solvent extraction system is used to extract gallium from the mother liquor to obtain a gallium-containing solvent extract phase.

[0034] S3. Desorb the gallium-loaded adsorption resin or back-extract the gallium-containing solvent extraction phase to obtain a gallium-rich solution;

[0035] S4. The gallium-rich solution is evaporated, concentrated, and electrolytically refined to obtain metallic gallium;

[0036] S5. The aluminum hydroxide precipitate is calcined to obtain aluminum oxide.

[0037] In this invention, the concentration of gallium in the gallium-rich mother liquor in step S1 is preferably 0.8~1.5 g / L, more preferably 1~1.4 g / L, and even more preferably 1.2 g / L.

[0038] In this invention, the adsorption resin in step S2 is preferably a chelating resin of a amine oxime;

[0039] The preferred amylopectin chelating resin is ZGD887Ga type amylopectin chelating resin.

[0040] In this invention, the adsorption in step S2 is preferably carried out at a pH of 13-14 and a temperature of 40-50°C, more preferably at a pH of 13.5 and a temperature of 45°C; the adsorption is preferably carried out in a resin adsorption column, the empty column flow rate of the resin column is preferably 1-2 BV / h, more preferably 1.4-1.6 BV / h, and more preferably 1.5 BV / h; the adsorption time is preferably 50-80 min, more preferably 60-70 min, and more preferably 65 min.

[0041] In this invention, the solvent extraction system in step S2 preferably contains the following components in volume fractions:

[0042] 15-20% di(2-ethylhexyl)phosphoric acid, 0-5% tributyl phosphate, balance sulfonated kerosene.

[0043] In this invention, the solvent extraction system described in step S2 is further preferably composed of the following components in volume fractions:

[0044] 16-18% di(2-ethylhexyl)phosphoric acid, 2-3% tributyl phosphate, balance sulfonated kerosene.

[0045] In this invention, the extraction temperature in step S2 is preferably 20~30℃, more preferably 24~26℃, and even more preferably 25℃. The extraction time is preferably 10~20min, more preferably 14~16min, and even more preferably 15min. The volume ratio of the solvent extraction system to the gallium-rich mother liquor during the extraction process is preferably 1:2~4, more preferably 1:2.5~3.5, and even more preferably 1:3.

[0046] In this invention, the desorption in step S3 preferably uses sulfuric acid solution as the desorbent; the concentration of the sulfuric acid solution is preferably 0.5~1 mol / L, more preferably 0.6~0.8 mol / L, and even more preferably 0.7 mol / L; the desorption flow rate is preferably 0.5~1 BV / h, more preferably 0.6~0.8 BV / h, and even more preferably 0.7 BV / h; the desorption temperature is preferably 20~40℃, more preferably 25~35℃, and even more preferably 30℃; the desorption time is preferably 20~60 min, more preferably 30~50 min, and even more preferably 40 min.

[0047] In this invention, the stripping agent in step S3 is preferably a hydrochloric acid solution and / or a sodium chloride solution; the concentration of the hydrochloric acid solution is preferably 5-6 mol / L, more preferably 5.5 mol / L; the concentration of the sodium chloride solution is preferably 0.4-0.6 mol / L, more preferably 0.5 mol / L; the stripping temperature is preferably 30-32℃, more preferably 31℃; the stripping time is preferably 10-12 min, more preferably 11 min; the volume ratio of the gallium-containing solvent extractant to the stripping agent during the stripping process is preferably 4-5:1, more preferably 4.5:1.

[0048] In this invention, the evaporation and concentration temperature in step S4 is preferably 120~150℃, more preferably 130~140℃, and even more preferably 135℃; the gallium concentration in the gallium-rich solution is preferably ≥50g / L, more preferably ≥55g / L, and even more preferably ≥60g / L.

[0049] The current density of the electrolytic refining is preferably 100~150A / m², more preferably 120~140A / m², and even more preferably 130A / m²; the temperature of the electrolytic refining is preferably 30~40℃, more preferably 34~36℃, and even more preferably 35℃.

[0050] In this invention, the calcination temperature in step S5 is preferably 950~1200℃, more preferably 1000~1100℃, and even more preferably 1050℃; the calcination time is preferably 3~8s, more preferably 4~6s, and even more preferably 5s.

[0051] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0052] Example 1

[0053] Sodium aluminate solution obtained from the leaching of bauxite (Pingguo gibbsite-type bauxite in Guangxi Zhuang Autonomous Region) was decomposed, and the decomposed slurry was subjected to solid-liquid separation to obtain aluminum hydroxide precipitate and gallium-rich mother liquor. The decomposition process is a routine process in Bayer alumina production. The main indicators of the gallium-rich mother liquor were as follows: gallium concentration 0.98 g / L, Al₂O₃ concentration 12 g / L, total impurities content 0.8 g / L, and pH 13.5.

[0054] Because the total impurity content of the gallium-rich mother liquor was 0.8 g / L, an adsorption resin was used to adsorb and enrich the gallium in the mother liquor. The specific operation was as follows: the gallium-rich mother liquor was pumped into a resin adsorption column packed with ZGD887Ga type amine oxime chelating resin. Adsorption was carried out at a pH of 13.5 and a temperature of 45℃. The empty column flow rate was controlled at 1.5 BV / h, and the adsorption time was 60 min, allowing the gallium in the mother liquor to be adsorbed by the resin, thus obtaining a gallium-loaded adsorption resin.

[0055] The gallium-loaded adsorption resin was desorbed. A 0.8 mol / L sulfuric acid solution was used as the desorbent, the desorption flow rate was 0.8 BV / h, the desorption temperature was 30℃, and the desorption time was 40 min, resulting in a gallium-rich solution with a gallium concentration of 25 g / L.

[0056] Gallium-rich solution was fed into an evaporation and concentration vessel and concentrated at 130°C to increase the gallium concentration in the solution to 50 g / L. The concentrate was then fed into an electrolytic cell for electrolytic refining at a current density of 120 A / m² and an electrolysis temperature of 35°C, ultimately yielding metallic gallium product.

[0057] Meanwhile, the aluminum hydroxide precipitate obtained during the decomposition process is sent to a roasting furnace for roasting treatment at a temperature of 1050℃ for 3 seconds to obtain the alumina product.

[0058] Testing revealed that the purity of the gallium metal obtained in this embodiment was 99.99%, and the total gallium recovery rate was 95.8%; the purity of the alumina product was 98.6%, meeting the industrial grade 1 alumina standard, with an alumina recovery rate of 93.5% and a total energy consumption of 320 kgce / t-Al2O3.

[0059] Example 2

[0060] Sodium aluminate solution obtained from the leaching of bauxite (gibbsite-type bauxite from Xiaoyi area, Shanxi Province) was decomposed, and the decomposed slurry was subjected to solid-liquid separation to obtain aluminum hydroxide precipitate and gallium-rich mother liquor. The decomposition process is a routine process in Bayer process alumina production. The main indicators of the gallium-rich mother liquor were as follows: gallium concentration was 0.38 g / L, and total impurity content was 1.5 g / L.

[0061] Because the total impurity content of the gallium-rich mother liquor was 1.5 g / L, a solvent extraction system was used to remove impurities from the mother liquor.

[0062] Gallium was extracted using a solvent extraction system comprising the following components by volume fraction: 20% di(2-ethylhexyl)phosphoric acid and 80% sulfonated kerosene. Extraction was carried out at 25°C for 15 min at a volume ratio of 1:3 between the solvent extraction system and the gallium-rich mother liquor, with a stirring speed of 30 r / min. After extraction, the mixture was allowed to stand for 10 min to separate the gallium-containing solvent extract phase and the raffinate. The gallium loading in the gallium-containing solvent extract phase was 1.08 g / L, the impurity co-extraction rate was less than 5%, and the gallium extraction rate was 94.7%.

[0063] The gallium-containing solvent extractant phase was back-extracted. The back-extractant was a hydrochloric acid solution with a concentration of 6 mol / L. During the back-extraction process, the volume ratio of the gallium-containing solvent extractant phase to the back-extractant was 4:1. The back-extraction was carried out at 30°C for 10 min with a stirring speed of 50 r / min. After back-extraction, the mixture was allowed to stand for 8 min to separate the gallium-rich solution and the regenerated organic phase, which could be recycled. The gallium concentration in the gallium-rich solution obtained after back-extraction was 25.2 g / L, the total impurity content was reduced to 0.07 g / L, and the gallium back-extraction rate was 98.2%.

[0064] Gallium-rich solution was fed into an evaporation and concentration vessel and concentrated at 120°C to increase the gallium concentration in the solution to 50 g / L. The concentrate was then fed into an electrolytic cell for electrolytic refining at a current density of 100 A / m² and an electrolysis temperature of 40°C to finally obtain metallic gallium product.

[0065] Meanwhile, the aluminum hydroxide precipitate obtained during the decomposition process is sent to a roasting furnace for roasting treatment at a temperature of 950℃ for 8 seconds to obtain the alumina product.

[0066] Testing revealed that the purity of the gallium metal obtained in this embodiment was 99.99%, and the total gallium recovery rate was 93.1%; the purity of the alumina product was 98.5%, meeting the industrial grade 1 alumina standard, with an alumina recovery rate of 93.2%, and the total energy consumption for the entire process was 322 kgce / t-Al2O3.

[0067] Example 3

[0068] The sodium aluminate solution obtained from the leaching of bauxite (imported trihydrate boehmite-type bauxite) was decomposed, and the decomposed slurry was subjected to solid-liquid separation to obtain aluminum hydroxide precipitate and gallium-rich mother liquor. This decomposition process is a routine process in Bayer process alumina production. The main indicators of the gallium-rich mother liquor were as follows: gallium concentration was 0.45 g / L, and total impurity content was 2.2 g / L.

[0069] Because the total impurity content of the gallium-rich mother liquor was 2.2 g / L, a solvent extraction system was used to extract gallium from the mother liquor. The solvent extraction system comprised the following components by volume fraction: 15% di(2-ethylhexyl)phosphoric acid, 5% tributyl phosphate, and 80% sulfonated kerosene. Extraction was carried out at 28°C for 20 min at a volume ratio of 1:4 to the gallium-rich mother liquor, with a stirring speed of 300 r / min. After extraction, the mixture was allowed to stand for 12 min to separate the gallium-containing solvent extract phase and the raffinate. The gallium loading in the gallium-containing solvent extract phase was 1.68 g / L, the impurity co-extraction rate was less than 4%, and the gallium extraction rate was 95.3%.

[0070] The gallium-containing solvent extractant phase was subjected to back-extraction. The back-extraction agent was a composite back-extraction agent consisting of 5 mol / L hydrochloric acid solution and 0.5 mol / L sodium chloride solution, with a volume ratio of hydrochloric acid solution to sodium chloride solution of 2:1. During the back-extraction process, the volume ratio of the gallium-containing solvent extractant phase to the back-extraction agent was 5:1. The back-extraction was carried out at 32°C for 12 min with a stirring speed of 250 r / min. After back-extraction, the mixture was allowed to stand for 10 min to separate the gallium-rich solution and the regenerated organic phase, which could be recycled. The gallium concentration in the gallium-rich solution obtained after back-extraction was 32.5 g / L, the total impurity content was reduced to 0.09 g / L, and the gallium back-extraction rate was 97.8%.

[0071] Gallium-rich solution was fed into an evaporation and concentration vessel and concentrated at 130°C to increase the gallium concentration in the solution to 55 g / L. Subsequently, the concentrate was fed into an electrolytic cell for electrolytic refining at a current density of 125 A / m² and an electrolysis temperature of 35°C, ultimately yielding metallic gallium product.

[0072] Meanwhile, the aluminum hydroxide precipitate obtained during the decomposition process is sent to a roasting furnace for roasting treatment at a temperature of 950℃ for 8 seconds to obtain the alumina product.

[0073] Testing revealed that the purity of the gallium metal obtained in this embodiment was 99.98%, and the total gallium recovery rate was 92.5%; the purity of the alumina product was 98.4%, meeting the industrial grade 1 alumina standard, with an alumina recovery rate of 92.8% and a total energy consumption of 326 kgce / t-Al2O3.

[0074] Comparative Example 1

[0075] The same gallium-rich mother liquor and aluminum hydroxide precipitate as in Example 1 were selected.

[0076] The specific operation is as follows: the gallium-rich mother liquor is pumped into an adsorption column filled with a strong basic anion exchange resin of model 201×7, and the adsorption operation is carried out under the conditions of pH 13.5 and temperature 45℃. The empty column flow rate of the resin column is controlled at 1.5 BV / h and the adsorption time is 60 min, so that the gallium in the mother liquor is adsorbed by the resin, and gallium-loaded adsorption resin is obtained.

[0077] The gallium-loaded adsorption resin was subjected to desorption treatment. The desorbent was a 0.3 mol / L hydrochloric acid solution, the desorption flow rate was 0.8 BV / h, the desorption temperature was 30℃, and the desorption time was 40 min, resulting in a gallium-rich solution.

[0078] The gallium-rich solution was fed into an evaporation and concentration vessel and concentrated at 150°C to increase the gallium concentration in the solution to 50 g / L. The concentrated solution was then electrolytically refined in an electrolytic cell at a current density of 130 A / m² and an electrolysis temperature of 45°C, ultimately yielding metallic gallium. Simultaneously, the aluminum hydroxide precipitate obtained during the decomposition process was calcined in a calcination furnace at 1100°C for 5 seconds to obtain alumina.

[0079] The purity of the gallium metal obtained in this comparative example was 99.2%, and the total gallium recovery rate was 82.1%; the purity of the alumina product was 98.6%, the alumina recovery rate was 85%, and the total energy consumption of the whole process was 380 kgce / t-Al2O3, which is 18.75% higher than that of Example 1 of this invention.

[0080] Comparative Example 2

[0081] The same gallium-rich mother liquor and aluminum hydroxide precipitate as in Example 2 were selected.

[0082] The solvent extraction system of Example 2 was replaced with components comprising the following volume fractions: 20% 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester and 80% sulfonated kerosene. Extraction was carried out at 25°C for 15 min at a volume ratio of 1:3 between the solvent extraction system and the gallium-rich mother liquor, with a stirring speed of 30 r / min. After extraction, the mixture was allowed to stand for 10 min to separate the gallium-containing solvent extract phase and the raffinate.

[0083] The gallium-containing solvent extractant phase was back-extracted. The back-extractant was a hydrochloric acid solution with a concentration of 4 mol / L. During the back-extraction process, the volume ratio of the gallium-containing solvent extractant phase to the back-extractant was 4:1. The back-extraction was carried out at 30°C for 10 min with a stirring speed of 50 r / min. After back-extraction, the mixture was allowed to stand for 8 min to separate the gallium-rich solution and the regenerated organic phase, which could be recycled.

[0084] The subsequent evaporation and concentration, electrolytic refining, and calcination processes are the same as in Example 4.

[0085] The purity of the gallium metal obtained in this comparative example was 99.1%, the total gallium recovery rate was 81.3%, the alumina recovery rate was 84.7%, and the total energy consumption of the process was 378 kgce / t-Al2O3, which is 17.4% higher than that of Example 2 of this invention.

[0086] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for the comprehensive recovery of alumina and gallium from bauxite, characterized in that, It includes the following steps: S1. The sodium aluminate solution obtained from the leaching of bauxite is decomposed, and the decomposed slurry is subjected to solid-liquid separation to obtain aluminum hydroxide precipitate and gallium-rich mother liquor. S2. Perform impurity analysis on the gallium-rich mother liquor. When the total impurity content in the gallium-rich mother liquor is ≤1g / L, use... Gallium in the mother liquor is adsorbed and enriched using an adsorption resin to obtain gallium-loaded adsorption resin. When the total impurity content in the gallium-rich mother liquor is >1 g / L, a solvent extraction system is used to remove gallium from the mother liquor. Extraction was performed to obtain a gallium-containing solvent extract phase; S3. Desorb the gallium-loaded adsorption resin or back-extract the gallium-containing solvent extraction phase to obtain a gallium-rich solution; S4. The gallium-rich solution is evaporated, concentrated, and electrolytically refined to obtain metallic gallium; S5. The aluminum hydroxide precipitate is calcined to obtain aluminum oxide.

2. The method for comprehensive recovery of alumina and gallium from bauxite according to claim 1, characterized in that, The gallium concentration in the gallium-rich mother liquor in step S1 is 0.8~1.5 g / L.

3. The method for comprehensive recovery of alumina and gallium from bauxite according to claim 1 or 2, characterized in that, The adsorption resin mentioned in step S2 is a chelating resin for amine oxime.

4. The method for comprehensive recovery of alumina and gallium from bauxite according to claim 3, characterized in that, The adsorption described in step S2 is carried out under the conditions of pH 13-14 and temperature 40-50℃; the adsorption is carried out in a resin adsorption column with an empty column flow rate of 1-2 BV / h; and the adsorption time is 50-80 min.

5. The method for comprehensive recovery of alumina and gallium from bauxite according to claim 1 or 2, characterized in that, The solvent extraction system described in step S2 comprises the following components in volume fractions: 15-20% di(2-ethylhexyl)phosphoric acid, 0-5% tributyl phosphate, balance sulfonated kerosene.

6. The method for comprehensive recovery of alumina and gallium from bauxite according to claim 5, characterized in that, The extraction temperature in step S2 is 20~30℃, the extraction time is 10~20min, and the volume ratio of the solvent extraction system to the gallium-rich mother liquor during the extraction process is 1:2~4.

7. The method for comprehensive recovery of alumina and gallium from bauxite according to claim 4, characterized in that, In step S3, sulfuric acid solution is used as the desorption agent; the concentration of the sulfuric acid solution is 0.5~1 mol / L; the desorption flow rate is 0.5~1 BV / h; the desorption temperature is 20~40℃; and the desorption time is 20~60 min.

8. The method for comprehensive recovery of alumina and gallium from bauxite according to claim 6, characterized in that, The back-extraction agent in step S3 is hydrochloric acid solution and / or sodium chloride solution. The back-extraction temperature is 30~32℃, the back-extraction time is 10~12min, and the volume ratio of gallium-containing solvent extractant to back-extraction agent during the back-extraction process is 4~5:

1.

9. The method for comprehensive recovery of alumina and gallium from bauxite according to claim 7 or 8, characterized in that, The evaporation and concentration in step S4 is carried out at a temperature of 120~150℃ until the gallium concentration in the gallium-rich solution is ≥50g / L. The current density of the electrolytic refining is 100~150A / m², and the temperature of the electrolytic refining is 30~40℃.

10. The method for comprehensive recovery of alumina and gallium from bauxite according to claim 1, characterized in that, The roasting temperature in step S5 is 950~1200℃, and the roasting time is 3~8s.

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