Process method for extracting gallium element from Bayer process seed precipitation mother liquor

Abstract

The invention relates to the technical field of resource recycling in an aluminum oxide production process, in particular to a process method for extracting gallium from Bayer process seed precipitation mother liquor. According to the technological method, the seed precipitation mother liquor in the Bayer process aluminum oxide production process is subjected to evaporation concentration, impurity removal crystallization is conducted through an impurity removal agent, continuous dynamic adsorption is conducted in ion exchange resin, and finally the element gallium in the seed precipitation mother liquor is recycled through secondary analysis technological treatment with acid. The impurity removal agent is used for impurity removal and crystallization, impurities can be removed in a short time, interference of the impurities on follow-up gallium extraction is avoided, in addition, the gallium extraction efficiency is improved by continuously and dynamically adsorbing the gallium-containing solution in the ion exchange resin, controlling the adsorption temperature, intermittently back-blowing the resin column in the adsorption process and selecting an acid for analysis and an analysis method. And the resin desorption rate and the gallium recovery rate are improved.

Description

Technical Field

[0001] The invention relates to the technical field of resource recycling in an alumina production process, and in particular to a process for extracting gallium from a Bayer process seed and denominator liquor. Background Art

[0002] Gallium is an electronic material with excellent performance and is the core material of second-generation and third-generation semiconductors. Its special physical and chemical properties make it widely used in integrated circuits of mobile phones, satellites, communications, national defense science and high-performance computers. It has high strategic and economic value and is known as the "backbone of the electronics industry". It is a basic resource metal for high-tech.

[0003] Bauxite contains a certain amount of gallium, so gallium can be extracted during the production of alumina, which not only realizes the full utilization of resources, but also improves the grade of alumina. The commonly used method for extracting gallium in the production of alumina is ion exchange, which is easy to operate. At present, NaOH is commonly used in industry to elute saturated resin to resolve the adsorbed gallium. The resolution rate is difficult to reach 70%, the gallium content of the resin residue is high, and the resin utilization rate is low. As the resin decays, the resolution rate will increase, but it will still not reach more than 80%. In addition, during the adsorption process of the Bayer process mother liquor, resin adhesion often occurs, and the resin adhesion reduces the adsorption points and affects the recovery of gallium. Summary of the invention

[0004] In order to further improve the recovery rate of gallium in the alumina production process, the present invention proposes a process for extracting gallium from the Bayer process denominator liquor, the specific steps of which are as follows:

[0005] (1) Evaporation and concentration: The Bayer process seed liquor is evaporated and concentrated to obtain a concentrated liquor;

[0006] (2) Crystallization: After the concentrated mother liquor is cooled to 25-50° C., the concentrated mother liquor is stirred or an impurity remover is added to the concentrated mother liquor to allow the impurities to crystallize and filter; the crystallization time is 1-4 hours, and a purified liquid is obtained after filtration;

[0007] (3) Adsorption: dilute the caustic soda concentration of the purified liquid to 140-180 g / L. The purified liquid can be diluted with water, filter washing liquid or other liquids with a caustic soda concentration of ≤100 g / L in other processes. Then, the diluted purified liquid is pumped into the ion exchange resin column for continuous dynamic adsorption until the ion exchange resin is saturated. The flow rate is 20-40 BV / h, that is, the volume of the solution (diluted purified liquid) passing through per hour is 20-40 times the volume of the resin bed. During the adsorption process, the bottom of the ion exchange resin column is blown once every 0.5-1 h. Each blowing time is 20-40 s. The blowing direction is opposite to the flow direction of the purified liquid. The adsorption cycle of the ion exchange resin column is 3-8 h. The adsorbed solution is returned to the Bayer process production system. Further, the ion exchange resin is selected from commercially available gallium extraction resins.

[0008] (4) Analysis: The saturated ion exchange resin is washed with water, and then the ion exchange resin is analyzed twice with the same acid to obtain a primary analysis solution and a secondary analysis solution. The secondary analysis solution is used as the analysis acid for the next cycle, and the primary analysis solution is used for subsequent purification and recovery of gallium, with a gallium content of 1-3 g / L;

[0009] (5) Cleaning: The analyzed ion exchange resin is cleaned with water or NaOH aqueous solution until the pH of the cleaning solution is 6-8.

[0010] Furthermore, the concentration of caustic soda in the Bayer process seed liquor in step 1 is not higher than 180 g / L, and the gallium content is 0.1-0.5 g / L.

[0011] Furthermore, the concentration of caustic soda in the concentrated mother liquor in step 1 is not less than 180 g / L.

[0012] Furthermore, the impurity remover in step 2 is a crystal naturally formed after evaporation of high-concentration Bayer process seed liquor, and the amount of the impurity remover added to the concentrated mother liquor is 5-30 g / L.

[0013] Furthermore, in the purified liquid of step 2, the concentration of vanadium element is ≤0.2 g / L.

[0014] Furthermore, in step 3, the temperature of the diluted purified liquid is maintained at 25° C.-45° C. during the adsorption process.

[0015] Furthermore, the acid used in step 4 is one or a mixture of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, chloroacetic acid or a secondary analysis solution, the acid concentration is 0.1 mol / L-3 mol / L, and each analysis time is 20-60 min.

[0016] Furthermore, during the analysis in step 4, the temperature is maintained at ≤10°C.

[0017] The above cycle is a complete evaporation concentration-crystallization-adsorption-analysis-cleaning process cycle, that is, in the initial stage of the process, the acid used in the analysis process is one or a mixture of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, and chloroacetic acid. After the initial stage, secondary analysis liquid is generated in the system, and the acid used in the analysis process uses the secondary analysis liquid of the previous cycle.

[0018] The beneficial effects of the present invention are:

[0019] (1) Using the crystals naturally formed after high-concentration evaporation of the Bayer process mother liquor as an impurity remover to obtain a purified liquid, effectively avoiding the interference of impurities on the subsequent gallium extraction, thereby increasing the efficiency of the ion exchange resin by 10%-15%. The impurity remover is used for impurity removal in a short time, does not introduce new impurities, and has no impact on the Bayer process;

[0020] (2) The diluted purified liquid is subjected to a continuous dynamic adsorption process using an ion exchange resin, and the temperature is maintained at 25°C-45°C, which accelerates the resin adsorption speed and efficiency. In addition, the purified liquid with a high caustic soda concentration has a large viscosity, which is not conducive to the adsorption of active points on the resin and is easy to stick. Therefore, the purified liquid is diluted to make it easier to adsorb and the resin is not easy to stick. At the same time, the addition of a back-blowing system can further blow away the sticking resin, further improving the recovery efficiency of the gallium element. Compared with the traditional resin adsorption process, the adsorption rate is increased by 5%-10%;

[0021] (3) The saturated resin is analyzed by acid, and the analysis rate can reach 80%-98%, which greatly improves the resin utilization rate compared with the use of NaOH. The temperature of the acid used during analysis is ≤10°C, which effectively neutralizes the heat released during analysis, increases the analysis rate by 5%-10%, reduces the gallium remaining on the resin, and improves the resin utilization rate.

[0022] (4) In addition, during the analysis process, the saturated resin is analyzed twice using acid. The first analysis solution has a high gallium concentration and is used for further purification and recovery of gallium. The second analysis solution has a low gallium concentration and can still be used as an acid for analysis in the next cycle, thereby reducing acid consumption and recovering gallium remaining in the resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The embodiments of the present invention are further described below with reference to the accompanying drawings, in which:

[0024] Figure 1 The present invention is a process flow chart for extracting gallium from Bayer process seed and denominator liquor;

[0025] Figure 2 Schematic diagram of an ion exchange resin column. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] Example 1 (initial stage of process)

[0028] (1) Evaporation and concentration: The concentration of caustic soda in the Bayer process mother liquor to be treated is 170 g / L, and the gallium content is 0.19 g / L. After evaporation and concentration, the concentration of caustic soda in the concentrated mother liquor is 210 g / L;

[0029] (2) Crystallization: After the concentrated mother liquor is cooled to 30° C., an impurity remover is added to the concentrated mother liquor. The impurity remover is a crystal naturally formed after evaporation of a high-concentration Bayer process seed liquor. After the impurity remover is added to the concentrated mother liquor, the impurity content is 5 g / L. Impurities are crystallized and filtered. The crystallization time is 4 hours. After filtration, a purified liquid is obtained. The vanadium concentration in the purified liquid is 0.07 g / L.

[0030] (3) Adsorption: Dilute the purified liquid with water. The caustic soda concentration of the diluted purified liquid is 170 g / L. Use a pump to transport the diluted purified liquid to the ion exchange resin column ( Continuous dynamic adsorption is carried out in a special resin for gallium extraction) until the ion exchange resin is saturated, with a flow rate of 20BV / h. During the adsorption process, the temperature of the purified liquid is maintained at 30°C, and the ion exchange resin column is intermittently blown, once every hour, for 30 seconds, wherein the one-hour interval is the time without blowing, and the blowing direction is opposite to the flow direction of the purified liquid. The adsorption cycle of the ion exchange resin column is 3h, and the solution after adsorption is returned to the Bayer process production system. The gallium concentration in the solution after adsorption is 0.07g / L, and the adsorption rate is 63.1%;

[0031] Among them, as attached Figure 2 As shown, the structure of the resin column for reverse blowing is that two left and right passages are arranged at the bottom outlet of the resin column, the left passage is a high-pressure air back-blowing pipe provided with a high-pressure air valve, and the right passage is a filtrate discharge pipe provided with a filtrate discharge valve. When back-blowing, the high-pressure air valve is opened, the filtrate discharge valve is closed, and ventilation back-blowing is carried out from the high-pressure air back-blowing pipe to the resin filter column. After the back-blowing is completed, the high-pressure air valve is closed, the filtrate discharge valve is opened, and the dynamic adsorption discharge is continued. The back-blowing structure and method in the following embodiments are consistent with this embodiment 1.

[0032] (4) Analysis: The saturated ion exchange resin was washed with water, and then analyzed twice with sulfuric acid. The parameters of the two analysis processes were the same: a concentration of 0.1 mol / L sulfuric acid was used, the analysis time was 30 min, and the temperature was maintained at 5-8°C to obtain a primary analysis solution and a secondary analysis solution. The secondary analysis solution was used for the next cycle of analysis, and the primary analysis solution was used for subsequent gallium purification and recovery. The gallium content in the primary analysis solution was 1.6 g / L, and the gallium analysis rate was 90.1%;

[0033] (5) Cleaning: The analyzed ion exchange resin is cleaned with water or NaOH aqueous solution until the pH of the cleaning solution is 6-8.

[0034] Example 2 (initial stage of process)

[0035] (1) Evaporation and concentration: The concentration of caustic soda in the Bayer process mother liquor to be treated is 175 g / L, and the gallium content is 0.29 g / L. After evaporation and concentration, the concentration of caustic soda in the concentrated mother liquor is 220 g / L;

[0036] (2) Crystallization: After the concentrated mother liquor is cooled to 25° C., an impurity remover is added to the concentrated mother liquor. The impurity remover is a crystal naturally formed after evaporation of a high-concentration Bayer process seed liquor. After the impurity remover is added to the concentrated mother liquor, the impurity content is 15 g / L. Impurities are crystallized and filtered. The crystallization time is 2 hours. After filtration, a purified liquid is obtained. The vanadium concentration in the purified liquid is 0.08 g / L.

[0037] (3) Adsorption: Dilute the purified liquid with belt filter washing water (caustic soda concentration is 90 g / L). The caustic soda concentration of the diluted purified liquid is 180 g / L. Use a pump to transport the diluted purified liquid to the ion exchange resin column ( Continuous dynamic adsorption is carried out in a special resin for gallium extraction) until the ion exchange resin is saturated, with a flow rate of 20BV / h. During the adsorption process, the temperature of the purified liquid is maintained at 45°C, and the ion exchange resin column is intermittently blown, once every 0.5 hours, and the blowing time is 20s, wherein the interval time is the time when no blowing is performed, and the blowing direction is opposite to the flow direction of the purified liquid. The adsorption cycle of the ion exchange resin column is 7h, and the solution after adsorption is returned to the Bayer process production system. The gallium concentration in the solution after adsorption is 0.10g / L, and the adsorption rate is 65.5%;

[0038] (4) Analysis: The saturated ion exchange resin was washed with water, and then the ion exchange resin was analyzed twice with hydrochloric acid. The parameters of the two analysis processes were the same: a concentration of 3 mol / L hydrochloric acid was used, the analysis time was 20 min, and the temperature was maintained at 7-9°C to obtain a primary analysis solution and a secondary analysis solution. The secondary analysis solution was used for the next cycle of analysis process, and the primary analysis solution was used for subsequent gallium purification and recovery. The gallium content in the primary analysis solution was 2.4 g / L, and the gallium analysis rate was 94.4%;

[0039] (5) Cleaning: The analyzed ion exchange resin is cleaned with water or NaOH aqueous solution until the pH of the cleaning solution is 6-8.

[0040] Example 3 (mid-stage process)

[0041] (1) Evaporation and concentration: The concentration of caustic soda in the Bayer process mother liquor to be treated is 160 g / L, and the gallium content is 0.12 g / L. After evaporation and concentration, the concentration of caustic soda in the concentrated mother liquor is 200 g / L;

[0042] (2) Crystallization: After the concentrated mother liquor is cooled to 50° C., an impurity remover is added to the concentrated mother liquor. The impurity remover is a crystal naturally formed after the Bayer process seed liquor is evaporated at a high concentration. After the impurity remover is added to the concentrated mother liquor, the impurity content is 30 g / L. Impurities are crystallized and filtered. The crystallization time is 1 hour. After filtration, a purified liquid is obtained. The vanadium concentration in the purified liquid is 0.08 g / L.

[0043] (3) Adsorption: Dilute the purified liquid with the wash water of the flat plate filter (the caustic soda concentration is 80 g / L). The caustic soda concentration of the diluted purified liquid is 140 g / L. Use a pump to transport the diluted purified liquid to the ion exchange resin column ( Continuous dynamic adsorption is carried out in a special resin for gallium extraction) until the ion exchange resin is saturated, with a flow rate of 40BV / h. During the adsorption process, the temperature of the purified liquid is maintained at 25°C, and the ion exchange resin column is intermittently blown, once every hour, for 40 seconds, wherein the one-hour interval is the time without blowing, and the blowing direction is opposite to the flow direction of the purified liquid. The adsorption cycle of the ion exchange resin column is 8 hours, and the solution after adsorption is returned to the Bayer process production system. The gallium concentration in the solution after adsorption is 0.04g / L, and the adsorption rate is 70.3%;

[0044] (4) Analysis: The saturated ion exchange resin was washed with water, and then the ion exchange resin was analyzed twice using the secondary analysis solution of the previous cycle. The parameters of the two analysis processes were the same: phosphoric acid with a concentration of 0.18 mol / L was used, the analysis time was 60 min, and the temperature was maintained at 8-10°C to obtain a primary analysis solution and a secondary analysis solution. The secondary analysis solution was used for the analysis process of the next cycle, and the primary analysis solution was used for the subsequent purification and recovery of gallium. The gallium content in the primary analysis solution was 1.4 g / L, and the gallium analysis rate was 90.3%;

[0045] (5) Cleaning: The analyzed ion exchange resin is cleaned with water or NaOH aqueous solution until the pH of the cleaning solution is 6-8.

[0046] Comparative Example 1

[0047] (1) Evaporation and concentration: The concentration of caustic soda in the Bayer process mother liquor to be treated is 170 g / L, and the gallium content is 0.19 g / L. After evaporation and concentration, the concentration of caustic soda in the concentrated mother liquor is 210 g / L;

[0048] (2) Crystallization: After the concentrated mother liquor is cooled to 30° C., an impurity remover is added to the concentrated mother liquor. The impurity remover is a crystal naturally formed after evaporation of a high-concentration Bayer process seed liquor. The amount of impurity remover added to the concentrated mother liquor is 5 g / L. Impurities are crystallized and filtered. The crystallization time is 4 hours. After filtration, a purified liquid is obtained. The vanadium concentration in the purified liquid is 0.1 g / L.

[0049] (3) Adsorption: The undiluted purified solution was delivered to the ion exchange resin column at a rate of 15 mL / min. Continuous dynamic adsorption is carried out in a special resin for gallium extraction until the ion exchange resin is saturated. During the adsorption process, the temperature of the purified liquid is maintained at 30°C, and the ion exchange resin column is intermittently blown: once every hour, each time for 30 seconds, the blowing direction is opposite to the flow direction of the purified liquid, and the adsorption cycle of the ion exchange resin column is 6 hours. The adsorbed solution is returned to the production system. The gallium concentration in the adsorbed solution is 0.13g / L, and the adsorption rate is 31.6%;

[0050] (4) Analysis: The saturated ion exchange resin was washed with water, and then the ion exchange resin was analyzed using NaOH. The concentration of NaOH was 5 mol / L, the analysis time was 60 min, and the temperature was maintained at 10°C. The analysis solution was obtained, and the gallium content was 1.1 g / L. The gallium analysis rate was 65.3%;

[0051] (5) Cleaning: The ion exchange resin after analysis is cleaned with solution x until the pH of the cleaning solution is 6-8.

[0052] Comparative Example 2

[0053] (1) Evaporation and concentration: The concentration of caustic soda in the Bayer process mother liquor to be treated is 170 g / L, and the gallium content is 0.17 g / L. After evaporation and concentration, the concentration of caustic soda in the concentrated mother liquor is 210 g / L;

[0054] (2) Crystallization: After the concentrated mother liquor is cooled to 30° C., an impurity remover is added to the concentrated mother liquor. The impurity remover is a crystal naturally formed after evaporation of a high-concentration Bayer process seed liquor. After the impurity remover is added to the concentrated mother liquor, the impurity content is 5 g / L. Impurities are crystallized and filtered. The crystallization time is 4 hours. After filtration, a purified liquid is obtained. The vanadium concentration in the purified liquid is 0.1 g / L.

[0055] (3) Adsorption: dilute the caustic soda concentration of the purified solution to 170 g / L, and place the ion exchange resin ( The gallium extraction resin was immersed in the diluted purified solution. During the adsorption process, the purified solution temperature was kept at 15°C. The adsorption cycle of the ion exchange resin column was 4 hours. The gallium concentration in the solution after adsorption was 0.12 g / L, and the adsorption rate was 27.5%.

[0056] (4) Analysis: The saturated ion exchange resin was washed with water, and then analyzed twice with sulfuric acid. The conditions of the two analysis processes were the same: the concentration of sulfuric acid was 0.03 mol / L, the analysis time was 30 min, and the temperature was maintained at 30°C. A primary analysis solution and a secondary analysis solution were obtained. The secondary analysis solution was used for the next primary analysis process, and the primary analysis solution was used for subsequent gallium purification and recovery. The gallium content of the primary analysis solution was 0.5 g / L, and the gallium analysis rate was 30.7%;

[0057] (5) Cleaning: The analyzed ion exchange resin is cleaned with water or NaOH aqueous solution until the pH of the cleaning solution is 6-8.

[0058] Some exemplary embodiments of the present invention are described above. It can be understood that the above embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention. The features in these embodiments can be recombined in a suitable manner, and the scheme obtained thereby is still within the protection scope required by the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without making creative work, that is, all modifications, equivalent substitutions and improvements made within the spirit and principles of this application, fall within the protection scope required by the present invention.

Claims

1. A process for extracting gallium from Bayer process seed denominator liquor, characterized in that: The following steps are involved: (1) Evaporation and concentration: The Bayer process seed liquor is evaporated and concentrated to obtain a concentrated liquor; (2) Crystallization: After the concentrated mother liquor is cooled to 25-50° C., the concentrated mother liquor is stirred or an impurity remover is added to the concentrated mother liquor, and impurities are crystallized and filtered. The crystallization time is 1-4 hours, and a purified liquid is obtained after filtration; (3) Adsorption: dilute the caustic soda concentration of the purified liquid to 140-180 g / L, and then use a pump to transport the diluted purified liquid to the ion exchange resin column for continuous dynamic adsorption until the ion exchange resin is saturated, with a flow rate of 20-40 BV / h. During the adsorption process, the bottom of the ion exchange resin column is blown once every 0.5-1 h, and each blowing time is 20-40 s. The blowing direction is opposite to the flow direction of the purified liquid. The adsorption cycle of the ion exchange resin column is 3-8 h, and the adsorbed solution is returned to the Bayer process production system; (4) Analysis: The saturated ion exchange resin is washed with water, and then the ion exchange resin is analyzed twice using the same acid to obtain a primary analysis solution and a secondary analysis solution. The secondary analysis solution is used as the analysis acid for the next cycle, and the primary analysis solution is used for subsequent gallium purification and recovery. The gallium content in the primary analysis solution is 1-3 g / L; (5) Cleaning: The analyzed ion exchange resin is cleaned with water or NaOH aqueous solution until the pH of the cleaning solution is 6-8.

2. The process for extracting gallium from Bayer process mother liquor according to claim 1, characterized in that: The concentration of caustic soda in the Bayer process seed liquor in step 1 is not higher than 180 g / L, and the gallium content is 0.1-0.5 g / L.

3. The process for extracting gallium from Bayer process mother liquor according to claim 1, characterized in that: The concentration of caustic soda in the concentrated mother liquor in step 1 is not less than 180 g / L.

4. The process for extracting gallium from Bayer process mother liquor according to claim 1, characterized in that: The impurity remover in step 2 is a crystal naturally formed after evaporation of high-concentration Bayer process seed liquor, and the amount of the impurity remover added to the concentrated mother liquor is 5-30 g / L.

5. The process for extracting gallium from Bayer process mother liquor according to claim 1, characterized in that: In the purified liquid of step 2, the concentration of vanadium element is ≤0.2 g / L.

6. The process for extracting gallium from Bayer process mother liquor according to claim 1, characterized in that: In step 3, the temperature of the diluted purified liquid is maintained at 25° C.-45° C. during the adsorption process.

7. The process for extracting gallium from Bayer process mother liquor according to claim 1, characterized in that: The acid used in step 4 is one or a mixture of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, chloroacetic acid or a secondary analysis solution, the acid concentration is 0.1 mol / L-3 mol / L, and each analysis time is 20-60 min.

8. The process for extracting gallium from Bayer process mother liquor according to claim 1, characterized in that: During the analysis in step 4, the temperature was maintained at ≤10°C.

Images