Method for recovering gallium from vanadium titano-magnetite converter slag pickle liquor

Abstract

The invention discloses a method for recovering gallium from vanadium titano-magnetite converter slag pickle liquor, which comprises the following steps: mixing the vanadium titano-magnetite converter slag pickle liquor with a reducing agent for reduction reaction to obtain reduced liquor; mixing the reduced solution with an alkaline solution to perform a first precipitation reaction to obtain gallium-rich precipitate; carrying out acid dissolution on the gallium-rich precipitate to obtain a gallium-containing acid solution; extracting the solution containing the gallic acid to obtain iron-rich raffinate and a gallium-rich organic phase; the gallium-rich organic phase is subjected to reverse extraction, and gallium-rich reverse extraction liquid is obtained; mixing the gallium-rich strip liquor with an alkaline solution or an acidic solution, and carrying out a second precipitation reaction to obtain a gallium hydroxide precipitate; and carrying out alkali dissolution on the gallium hydroxide precipitate to obtain a gallium-rich solution. According to the method, gallium is recycled from the vanadium titano-magnetite converter slag pickle liquor through the processes of reduction, precipitation, dissolution, extraction, reverse extraction, precipitation and alkali dissolution, the method has the advantages of being good in impurity removal effect and easy to industrialize, and the obtained gallium-rich solution can be directly used for the subsequent gallium electrolysis procedure.

Description

Technical Field

[0001] The invention relates to the field of rare metal hydrometallurgy, and in particular to a method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution. Background Art

[0002] Rare metal gallium is an important strategic resource and a key raw material for semiconductors and optical devices. It is widely used in communications, aerospace, new energy and other fields. Gallium is widely distributed in the earth's crust. It generally does not exist in the form of a single substance, but is associated with vanadium-titanium magnetite, lead-zinc ore, bauxite, coal mine, iron ore, etc. in an isomorphous manner.

[0003] At present, the gallium content in vanadium-titanium magnetite converter slag is 0.04-0.05%, which is much higher than the requirement of 30 g / t for gallium industrial ore grade. It is a gallium-rich resource with good comprehensive recycling value. However, its mineral composition is relatively complex, containing a variety of valuable metal elements such as gallium, iron, vanadium, zinc, titanium, etc., among which the iron content is relatively high, exceeding 63%. Due to the similar properties of Fe(Ⅲ) and Ga(Ⅲ), the separation and recovery of gallium in a high-concentration iron environment becomes difficult, and the extraction rate of gallium is significantly reduced under strong acidic conditions. At present, the gallium extraction technology from vanadium-titanium magnetite converter slag is still insufficient in the selective extraction of gallium, and industrial application has not yet been realized. The recovery rate of gallium is low, resulting in a great waste of gallium resources.

[0004] Therefore, it is necessary to develop a method for selectively separating and recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, the purpose of the present invention is to provide a method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution, so as to solve the problem of low gallium recovery rate in the strong acidic and high iron concentration environment of the prior art.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions: The present invention provides a method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution, comprising the following steps: S1: mixing the vanadium-titanium magnetite converter slag acid leaching liquid with a reducing agent to carry out a reduction reaction to obtain a reduced liquid; S2: mixing the reduced liquid with an alkaline solution to perform a first precipitation reaction to obtain a gallium-rich precipitate; S3: acid dissolving the gallium-rich precipitate to obtain a gallium-containing acid solution; S4: extracting the gallium-containing acid solution to obtain an iron-rich raffinate and a gallium-rich organic phase; S5: stripping the gallium-rich organic phase to obtain a gallium-rich stripping solution and a lean organic phase; S6: mixing the gallium-rich stripping solution with an alkaline solution or an acidic solution to perform a second precipitation reaction to obtain a gallium hydroxide precipitate; S7: dissolving the gallium hydroxide precipitate with alkali to obtain a gallium-rich solution.

[0007] Preferably, in step S1, the amount of the reducing agent added is 0.5-2.5 times the molar amount of the trivalent iron ion in the vanadium-titanium magnetite converter slag acid leaching solution; the reducing agent is one or more of iron powder, stannous chloride, and sodium sulfite; the reduction reaction temperature is 40-80°C, and the reduction reaction time is 15-50 min; Preferably, the vanadium-titanium magnetite converter slag acid leaching solution contains 0.04-0.06 g / L of gallium, 55-100 g / L of iron, and a free acidity of 5.0-7.0 mol / L.

[0008] Preferably, in step S2, the pH of the first precipitation reaction is 4-7, the reaction temperature is 40-90° C., and the reaction time is 20-60 min.

[0009] Preferably, in step S3, the acid dissolution conditions include: the concentration of the acid solution is 5-8 mol / L, the liquid-solid ratio of the acid solution to the gallium-rich precipitate is (5-8): 1 mL / g; the acid dissolution temperature is 40-90°C, and the acid dissolution time is 0.5-4 h.

[0010] Preferably, in step S4, the extraction organic phase used for extraction includes an extractant and a diluent, wherein the extractant is one or more of tributyl phosphate and 2-ethylhexyl mono-2-ethylhexyl phosphate, and the diluent is sulfonated kerosene or industrial kerosene; and the mass ratio of the extractant to the diluent is (4-40): (60-96).

[0011] Preferably, in step S4, the volume ratio of the organic phase used for extraction to the gallium acid solution is 1:(0.5-15), and the number of extraction stages is 3-8.

[0012] Preferably, in step S5, the stripping agent used in stripping is one or more of sodium hydroxide, ammonia water, ammonium chloride, sodium carbonate, sodium bicarbonate, and pure water; The volume ratio of the gallium-rich organic phase to the stripping agent is (1-7): (1-3), and the stripping time is 5-30 min.

[0013] Preferably, in step S6, the pH of the second precipitation reaction is 5-7, the reaction temperature is 40-95° C., and the reaction time is 30-120 min.

[0014] Preferably, in step S7, the conditions for alkaline dissolution include: the concentration of the alkaline solution is 2.5-4 mol / L, the liquid-solid ratio of the alkaline solution to the gallium hydroxide precipitate is (3-7): 1 mL / g; the temperature of the alkaline dissolution is 40-70°C, and the alkaline dissolution time is 1-4 h.

[0015] Preferably, the method further comprises regenerating the lean organic phase obtained in step S5 to obtain a regenerated organic phase, and recycling the regenerated organic phase for the extraction step.

[0016] The beneficial effects of the present invention are: The present invention adopts a reduction-precipitation-dissolution coupling process combined with an extraction-stripping process to achieve efficient separation of gallium and impurity ions. The gallium concentration in the obtained gallium-rich solution is higher than 18 g / L, and the iron concentration is lower than 0.07 g / L, which can meet the requirements of the electrolysis process and can be directly used in the subsequent electrolysis of metallic gallium process.

[0017] The reduction-precipitation-dissolution-extraction-strip-precipitation-alkali dissolution process provided by the present invention recovers gallium from the acid leaching solution of vanadium-titanium magnetite converter slag, has the advantages of good impurity removal effect and easy industrialization, and provides technical support for the efficient and selective recovery of gallium from vanadium-titanium magnetite converter slag.

[0018] The present invention adopts a relatively low concentration of TBP or a combination of TBP and P507 as an extractant to efficiently and selectively extract gallium from the acid leaching solution of vanadium-titanium magnetite converter slag without adjusting the pH, thereby realizing the separation of gallium from metals such as Fe, Zn, V, and Ti, and the extraction recovery rate of gallium can reach more than 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings of the embodiment are briefly introduced below.

[0020] Figure 1 It is a schematic diagram of a method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The iron content in the acid leaching solution of vanadium-titanium magnetite converter slag is relatively high, with a concentration greater than 55 g / L, and the gallium content is also relatively rich. Due to the similar properties of Fe(Ⅲ) and Ga(Ⅲ), the separation and recovery of gallium in a high-concentration iron environment is relatively difficult. Figure 1 The embodiment of the present invention provides a method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution, comprising the following steps: S1: Mix the vanadium-titanium magnetite converter slag acid leaching solution with a reducing agent, and carry out a reduction reaction to obtain a reduced solution; wherein, the amount of the reducing agent added is 0.5-2.5 times the molar amount of trivalent iron ions in the vanadium-titanium magnetite converter slag acid leaching solution; the reducing agent is one or more of iron powder, stannous chloride, and sodium sulfite; the purity of the reducing agent is greater than 99%, the temperature of the reduction reaction is 40-80°C, and the reduction reaction time is 15-50 min. The trivalent iron in the vanadium-titanium magnetite converter slag acid leaching solution is reduced to divalent iron through the reduction reaction.

[0023] S2: Mix the reduced solution with an alkaline solution, and perform a first precipitation reaction at a pH of 4-7 and a temperature of 40-90°C for 20-60 min to obtain a gallium-rich precipitate. The alkaline solution includes but is not limited to sodium hydroxide. The gallium ions in the solution are converted into precipitates through the first precipitation reaction. After the precipitation is completed, the gallium precipitation rate can reach 90-100%, and the iron precipitation rate can reach 20-75%.

[0024] S3: Add an acid solution with a concentration of 5-8 mol / L to the gallium-rich precipitate, and the liquid-solid ratio of the acid solution to the gallium-rich precipitate is (5-8): 1 mL / g; acid dissolution is performed at a temperature of 40-90°C, and the acid dissolution time is 0.5-4 h to obtain a gallium-containing acid solution. The acid solution includes but is not limited to a hydrochloric acid solution. The gallium ions in the vanadium-titanium magnetite converter slag acid leaching solution are enriched by acid dissolution. Compared with the vanadium-titanium magnetite converter slag acid leaching solution, the gallium concentration of the gallium-containing acid solution can be enriched 4-8 times, and the iron removal rate reaches 30-60%.

[0025] S4: Extract the gallium-containing acid solution to obtain an iron-rich raffinate and a gallium-rich organic phase; wherein the extraction organic phase used for extraction includes an extractant and a diluent, the extractant is one or more of tributyl phosphate (TBP) and 2-ethylhexyl phosphate mono-2-ethylhexyl ester (P507), and the diluent is sulfonated kerosene or industrial kerosene; the mass ratio of the extractant to the diluent is (4-40): (60-96). The volume ratio of the extraction organic phase to the gallium-containing acid solution is 1: (0.5-15), and the number of extraction levels is 3 to 8. Through extraction, impurity ions such as iron, vanadium, zinc, and titanium in the gallium-containing acid solution enter the aqueous phase, while gallium enters the organic phase, thereby achieving effective separation of gallium and impurity ions, and the extraction recovery rate of gallium can reach more than 99%.

[0026] S5: Stripping the gallium-rich organic phase to obtain a gallium-rich stripping solution and a lean organic phase; wherein the stripping agent used for stripping is one or more of sodium hydroxide, ammonia water, ammonium chloride, sodium carbonate, sodium bicarbonate, and pure water; the volume ratio of the gallium-rich organic phase to the stripping agent is (1-7): (1-3), and the stripping time is 5-30 min. When the stripping agent is one or more of sodium hydroxide, ammonia water, ammonium chloride, sodium carbonate, and sodium bicarbonate, its concentration is preferably 1-1.5 mol / L. Through stripping, the gallium in the gallium-rich organic phase enters the aqueous phase, thereby obtaining an aqueous solution enriched with gallium ions.

[0027] S6: The gallium-rich stripping solution is mixed with an alkaline solution or an acidic solution, and a second precipitation reaction is carried out at a pH of 5-7 and a temperature of 40-95°C for 30-120 minutes to obtain a gallium hydroxide precipitate. The gallium in the gallium-rich stripping solution is formed into a gallium hydroxide precipitate through the second precipitation reaction, while a small amount of impurity metal ions remaining in the gallium-rich stripping solution still exist in the solution, achieving further purification to obtain gallium hydroxide with higher purity.

[0028] S7: Add an alkaline solution with a concentration of 2.5-4 mol / L to the gallium hydroxide precipitate, the liquid-to-solid ratio of the alkaline solution to the gallium hydroxide precipitate is (3-7): 1 mL / g, and perform alkaline dissolution at 40-70°C for 1-4 h to obtain a gallium-rich solution. The alkaline solution includes but is not limited to sodium hydroxide solution. The gallium hydroxide is dissolved by alkaline dissolution to obtain a high-concentration gallium-rich solution, in which the gallium concentration is higher than 18 g / L and the iron concentration is lower than 0.07 g / L, which can be directly used in the subsequent electrolytic gallium production process.

[0029] In some preferred embodiments, the process further comprises regenerating the lean organic phase obtained in step S5 to obtain a regenerated organic phase, and recycling the regenerated organic phase for the extraction step in step S4. For example, the lean organic phase is washed with deionized water until the pH remains stable to obtain a regenerated organic phase.

[0030] In some preferred embodiments, the vanadium-titanium magnetite converter slag acid leaching solution contains 0.04-0.06 g / L of gallium, major impurities include Fe, V, Zn, Ti, and the Fe concentration is 55-100 g / L, the concentrations of other impurity ions are not higher than 2 g / L, and the free acidity is 5.0-7.0 mol / L.

[0031] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below.

[0032] In the following examples and comparative examples, the main components of the vanadium-titanium magnetite converter slag acid leaching solution are shown in Table 1.

[0033] Table 1 Main element contents of vanadium-titanium magnetite converter slag acid leaching solution

[0034] Example 1 A method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution comprises the following steps: (1) Add iron powder to the acid leaching solution of vanadium-titanium magnetite converter slag, wherein the molar ratio of iron powder to trivalent iron ions in the acid leaching solution of vanadium-titanium magnetite converter slag is 0.7:1. Stir in a constant temperature water bath at 60°C for 20 min, and obtain the reduced solution after filtration, i.e., gallium solution containing divalent iron ions, with an iron reduction rate of 99.4%.

[0035] (2) The pH of the reduced solution was adjusted to 6 with 5 mol / L NaOH solution, reacted at 60°C for 30 min, and then filtered to obtain a gallium-rich precipitate. After precipitation, the gallium precipitation rate reached 98% and the iron precipitation rate was 70%.

[0036] (3) 6 mol / L HCl and gallium-rich precipitate were added into the reactor at a liquid-to-solid ratio of 7:1 mL / g. The reactor was placed in a 60°C constant temperature bath and stirred for 3 h. After filtering, a gallium acid solution was obtained.

[0037] (4) Gallium in the gallium-containing acid solution was extracted using 6% TBP and 94% sulfonated kerosene to obtain an iron-rich raffinate and a gallium-rich organic phase. The volume ratio of the extracted organic phase to the gallium-containing acid solution was 1:6, and the extraction lasted for 5 min. After four-stage countercurrent extraction, the gallium extraction rate was 99.07%, and the iron extraction rate was 1.27%. Most of the impurities remained in the raffinate, achieving efficient and selective extraction of gallium. The extraction results are shown in Table 2.

[0038] Table 2 Extraction results

[0039] (5) The gallium-rich organic phase was stripped with 1.5 mol / L ammonium chloride as the stripping agent (the pH of the stripping system was adjusted to 3 with aqueous ammonia). The volume ratio of the gallium-rich organic phase to the stripping agent was 1:1. The stripping was carried out for 10 min to obtain a gallium-rich stripping solution and a lean organic phase. The gallium recovery rate after stripping was over 95%.

[0040] (6) The pH of the gallium-rich stripping solution was adjusted to 6 using 5 mol / L sodium hydroxide and reacted at 50°C for 100 min to obtain gallium hydroxide precipitate.

[0041] (7) A 2.5 mol / L sodium hydroxide solution was added to the gallium hydroxide precipitate, and the liquid-solid ratio of the sodium hydroxide solution to the gallium hydroxide precipitate was 6:1 mL / g. The reaction was carried out at 40°C for 2 h to obtain a gallium-rich solution. The gallium concentration in the obtained gallium-rich solution was 18.3 g / L and the iron concentration was 0.029 g / L, which achieved the separation of gallium and impurity ions in the acid leaching solution of vanadium-titanium magnetite converter slag, meeting the requirements of subsequent electrolysis of metallic gallium.

[0042] Example 2 A method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution comprises the following steps: (1) Add iron powder to the acid leaching solution of vanadium-titanium magnetite converter slag, wherein the molar ratio of iron powder to trivalent iron ions in the acid leaching solution of vanadium-titanium magnetite converter slag is 0.55:1. Stir in a constant temperature water bath at 60°C for 20 min, and filter to obtain the reduced solution, i.e., gallium solution containing divalent iron ions, with an iron reduction rate of 94%.

[0043] (2) The pH of the reduced solution was adjusted to 5.5 with 6 mol / L NaOH solution, and the reaction was carried out at 60°C for 30 min, and then the gallium-rich precipitate was obtained by filtration. After the precipitation was completed, the gallium precipitation rate reached 93% and the iron precipitation rate reached 52%.

[0044] (3) 6 mol / L HCl and gallium-rich precipitate were added into the reactor at a liquid-to-solid ratio of 7:1 mL / g. The reactor was placed in a 60°C constant temperature bath and stirred for 3 h. After filtering, a gallium acid solution was obtained.

[0045] (4) Gallium in the gallium-containing acid solution was extracted using 6% TBP and 94% sulfonated kerosene to obtain an iron-rich raffinate and a gallium-rich organic phase. The volume ratio of the extracted organic phase to the gallium-containing acid solution was 1:7, and the extraction lasted for 5 min. After a single-stage extraction, the gallium extraction rate was 95.75%, and the iron extraction rate was 3.3%. Most of the impurities remained in the raffinate, achieving efficient and selective extraction of gallium. The extraction results are shown in Table 3.

[0046] Table 3 Extraction results

[0047] (5) The gallium-rich organic phase was stripped with 1 mol / L sodium hydroxide as the stripping agent. The volume ratio of the gallium-rich organic phase to the stripping agent was 1:1. The stripping was performed for 10 min to obtain a gallium-rich stripping solution and a lean organic phase. The gallium recovery rate after stripping was over 97%.

[0048] (6) The pH of the gallium-rich stripping solution was adjusted to 6 using 4 mol / L hydrochloric acid and reacted at 50°C for 100 min to obtain gallium hydroxide precipitate.

[0049] (7) Adding a sodium hydroxide solution with a concentration of 3 mol / L to the gallium hydroxide precipitate, the liquid-solid ratio of the sodium hydroxide solution to the gallium hydroxide precipitate is 7:1 mL / g, and reacting at 40°C for 2 h to obtain a gallium-rich solution. The gallium concentration in the obtained gallium-rich solution is 20.4 g / L and the iron concentration is 0.069 g / L, which meets the requirements of subsequent electrolysis of metallic gallium.

[0050] Example 3 A method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution comprises the following steps: (1) Add stannous chloride to the acid leaching solution of vanadium-titanium magnetite converter slag, wherein the molar ratio of stannous chloride to trivalent iron ions in the acid leaching solution of vanadium-titanium magnetite converter slag is 2.1:1. Stir in a constant temperature water bath at 60°C for 20 min, and filter to obtain the reduced solution, i.e., gallium solution containing divalent iron ions, with an iron reduction rate of 99.2%.

[0051] (2) The pH of the reduced solution was adjusted to 6 with 5 mol / L NaOH solution, reacted at 70°C for 30 min, and then filtered to obtain a gallium-rich precipitate. After precipitation, the gallium precipitation rate reached 98% and the iron precipitation rate was 73%.

[0052] (3) 6 mol / L HCl and gallium-rich precipitate were added into the reactor at a liquid-to-solid ratio of 6:1 mL / g. The reactor was placed in a 60°C constant temperature bath and stirred for 3 h. After filtering, a gallium acid solution was obtained.

[0053] (4) Gallium in the gallium-containing acid solution was extracted using 6% TBP and 94% sulfonated kerosene to obtain an iron-rich raffinate and a gallium-rich organic phase. The volume ratio of the extracted organic phase to the gallium-containing acid solution was 1:12, and the extraction time was 5 min. After single-stage extraction, the gallium extraction rate was 93.7%, and the iron extraction rate was 1.22%. Most of the impurities remained in the raffinate, achieving efficient and selective extraction of gallium. The extraction results are shown in Table 4.

[0054] Table 4 Extraction results

[0055] (5) The gallium-rich organic phase was stripped with 1 mol / L sodium hydroxide as the stripping agent. The volume ratio of the gallium-rich organic phase to the stripping agent was 1:2. The stripping was performed for 10 min to obtain a gallium-rich stripping solution and a lean organic phase. The gallium recovery rate after stripping was over 97%.

[0056] (6) The pH of the gallium-rich stripping solution was adjusted to 6 using 4 mol / L hydrochloric acid and reacted at 50°C for 100 min to obtain gallium hydroxide precipitate.

[0057] (7) Adding a sodium hydroxide solution with a concentration of 4 mol / L to the gallium hydroxide precipitate, the liquid-solid ratio of the sodium hydroxide solution to the gallium hydroxide precipitate is 7:1 mL / g, and reacting at 50°C for 4 h to obtain a gallium-rich solution. The gallium concentration in the obtained gallium-rich solution is 26.8 g / L and the iron concentration is 0.063 g / L, which meets the requirements of the subsequent electrolysis of metallic gallium.

[0058] Example 4 A method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution comprises the following steps: (1) Sodium sulfite was added to the acid leaching solution of vanadium-titanium magnetite converter slag, wherein the molar ratio of sodium sulfite to trivalent iron ions in the acid leaching solution of vanadium-titanium magnetite converter slag was 0.7:1. The mixture was stirred in a constant temperature water bath at 60°C for 20 min, and the reduced solution was obtained after filtration, i.e., a gallium solution containing divalent iron ions, and the iron reduction rate was 99.4%.

[0059] (2) The pH of the reduced solution was adjusted to 6 with 5 mol / L NaOH solution, reacted at 70°C for 30 min, and then filtered to obtain a gallium-rich precipitate. After precipitation, the gallium precipitation rate reached 98% and the iron precipitation rate was 73%.

[0060] (3) 6 mol / L HCl and gallium-rich precipitate were added into the reactor at a liquid-to-solid ratio of 6:1 mL / g. The reactor was placed in a 60°C constant temperature bath and stirred for 3 h. After filtering, a gallium acid solution was obtained.

[0061] (4) Gallium in the gallium-containing acid solution was extracted using 2% TBP, 8% P507 and 90% sulfonated kerosene to obtain an iron-rich raffinate and a gallium-rich organic phase. The volume ratio of the extracted organic phase to the gallium-containing acid solution was 1:12, and the extraction was 5 min. After four-stage countercurrent extraction, the gallium extraction rate was 98.8%, and the iron extraction rate was 1.72%. Most of the impurities remained in the raffinate, achieving efficient and selective extraction of gallium. The extraction results are shown in Table 5.

[0062] Table 5 Extraction results

[0063] (5) The gallium-rich organic phase was stripped with pure water as the stripping agent. The volume ratio of the gallium-rich organic phase to the stripping agent was 1:2. The stripping was performed for 10 min to obtain a gallium-rich stripping solution and a lean organic phase. The gallium recovery rate after stripping was over 97%.

[0064] (6) The pH of the gallium-rich stripping solution was adjusted to 6 using 5 mol / L sodium hydroxide and reacted at 50°C for 100 min to obtain gallium hydroxide precipitate.

[0065] (7) Adding a sodium hydroxide solution with a concentration of 3 mol / L to the gallium hydroxide precipitate, the liquid-solid ratio of the sodium hydroxide solution to the gallium hydroxide precipitate is 7:1 mL / g, and reacting at 60°C for 2 h to obtain a gallium-rich solution. The gallium concentration in the obtained gallium-rich solution is 24.13 g / L and the iron concentration is 0.026 g / L, which meets the requirements of subsequent electrolysis of metallic gallium.

[0066] Example 5 A method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution comprises the following steps: (1) Sodium sulfite solution was added to the acid leaching solution of vanadium-titanium magnetite converter slag, the concentration of which was 100 g / L, and the molar ratio of sodium sulfite to trivalent iron ions in the acid leaching solution of vanadium-titanium magnetite converter slag was 0.7:1. The solution was stirred in a constant temperature water bath at 60°C for 20 min, and the reduced solution was obtained after filtration, i.e., gallium solution containing divalent iron ions, and the iron reduction rate was 99.3%.

[0067] (2) The pH of the reduced solution was adjusted to 6 with 5 mol / L NaOH solution, reacted at 60°C for 30 min, and then filtered to obtain a gallium-rich precipitate. After precipitation, the gallium precipitation rate reached 98% and the iron precipitation rate was 70%.

[0068] (3) 6 mol / L HCl and gallium-rich precipitate were added into the reactor at a liquid-to-solid ratio of 6:1 mL / g. The reactor was placed in a 60°C constant temperature bath and stirred for 3 h. After filtering, a gallium acid solution was obtained.

[0069] (4) Gallium in the gallium-containing acid solution was extracted using 6% TBP and 94% sulfonated kerosene to obtain an iron-rich raffinate and a gallium-rich organic phase. The volume ratio of the extracted organic phase to the gallium-containing acid solution was 1:6, and the extraction was performed for 5 min. After four-stage countercurrent extraction, the gallium extraction rate was 98.44%, and the iron extraction rate was 1.13%. Most of the impurities remained in the raffinate, achieving efficient and selective extraction of gallium. The extraction results are shown in Table 6.

[0070] Table 6 Extraction results

[0071] (5) The gallium-rich organic phase was stripped with pure water as the stripping agent. The volume ratio of the gallium-rich organic phase to the stripping agent was 1:1. The stripping was performed for 10 min to obtain a gallium-rich stripping solution and a lean organic phase. The gallium recovery rate after stripping was over 97%.

[0072] (6) The pH of the gallium-rich stripping solution was adjusted to 6 using 5 mol / L sodium hydroxide and reacted at 50°C for 100 min to obtain gallium hydroxide precipitate.

[0073] (7) Adding a sodium hydroxide solution with a concentration of 3 mol / L to the gallium hydroxide precipitate, the liquid-solid ratio of the sodium hydroxide solution to the gallium hydroxide precipitate is 7:1 mL / g, and reacting at 60°C for 2 h to obtain a gallium-rich solution. The gallium concentration in the obtained gallium-rich solution is 21.54 g / L and the iron concentration is 0.03 g / L, which meets the requirements of subsequent electrolysis of metallic gallium.

[0074] Comparative Example 1 This comparative example is basically the same as Example 1, except that the reduction process of step (1) is omitted in this comparative example, and the vanadium-titanium magnetite converter slag acid leaching solution is directly precipitated, and other conditions are the same. The extraction results are shown in Table 7, where the iron extraction rate is 95.58%, and the gallium extraction rate is 97.34%. It is impossible to separate gallium from impurity ion iron. The gallium concentration in the final gallium-rich solution is 18.4 g / L, and the iron concentration is 23.4 g / L, which cannot meet the requirements of subsequent electrolysis of metallic gallium.

[0075] Table 7 Extraction results

[0076] Comparative Example 2 This comparative example is basically the same as Example 1, except that the precipitation and acid dissolution process of steps (2) and (3) is omitted in this comparative example, and the vanadium-titanium magnetite converter slag acid leaching liquid is directly extracted after reduction, and other conditions are the same. The extraction results are shown in Table 8, where the gallium extraction rate is 89.46%, and the iron extraction rate is 3.47%. Due to the excessive amount of iron powder in the reduction reaction, the iron concentration in the liquid after reduction is too high, which is 115.34 g / L. The iron concentration in the gallium-rich organic phase after extraction is 24 g / L, and the separation of gallium and impurity ion iron cannot be achieved. In addition, the gallium enrichment ratio is not high. The gallium concentration in the final gallium-rich solution is 5.6 g / L, and the iron concentration is 6.4 g / L, which cannot meet the requirements of subsequent electrolysis of metallic gallium.

[0077] Table 8 Extraction results

[0078] In summary, the present invention adopts the reduction-precipitation-dissolution-extraction-strip extraction-precipitation-alkali dissolution process to recover gallium from the acid leaching solution of vanadium-titanium magnetite converter slag, thereby achieving effective separation of gallium and iron. The gallium concentration in the obtained gallium-rich solution is higher than 18 g / L, and the iron concentration is lower than 0.07 g / L, and the solution can be directly used in the subsequent electrolysis of metallic gallium process.

[0079] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For matters that are not described in detail in some embodiments, reference may be made to the description in other embodiments.

[0080] The above-mentioned embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution, characterized in that: The following steps are involved: S1: mixing the vanadium-titanium magnetite converter slag acid leaching liquid with a reducing agent to carry out a reduction reaction to obtain a reduced liquid; S2: mixing the reduced liquid with an alkaline solution to perform a first precipitation reaction to obtain a gallium-rich precipitate; S3: acid-dissolving the gallium-rich precipitate to obtain a gallium-containing acid solution; S4: extracting the gallium-containing acid solution to obtain an iron-rich raffinate and a gallium-rich organic phase; S5: stripping the gallium-rich organic phase to obtain a gallium-rich stripping solution and a lean organic phase; S6: mixing the gallium-rich stripping solution with an alkaline solution or an acidic solution to perform a second precipitation reaction to obtain a gallium hydroxide precipitate; S7: dissolving the gallium hydroxide precipitate with alkali to obtain a gallium-rich solution.

2. The method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution according to claim 1, characterized in that: In step S1, the amount of the reducing agent added is 0.5-2.5 times the molar amount of trivalent iron ions in the vanadium-titanium magnetite converter slag acid leaching solution; the reducing agent is one or more of iron powder, stannous chloride, and sodium sulfite; the temperature of the reduction reaction is 40-80°C, and the reaction time is 15-50 min; The vanadium-titanium magnetite converter slag acid leaching solution contains 0.04-0.06 g / L of gallium, 55-100 g / L of iron, and a free acidity of 5.0-7.0 mol / L.

3. The method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution according to claim 1, characterized in that: In step S2, the pH of the first precipitation reaction is 4-7, the reaction temperature is 40-90° C., and the reaction time is 20-60 min.

4. The method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution according to claim 1, characterized in that: In step S3, the acid dissolution conditions include: the concentration of the acid solution is 5-8 mol / L, the liquid-solid ratio of the acid solution to the gallium-rich precipitate is (5-8): 1 mL / g; the temperature of the acid dissolution is 40-90°C, and the acid dissolution time is 0.5-4 h.

5. The method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution according to claim 1, characterized in that: In step S4, the extraction organic phase used in the extraction includes an extractant and a diluent, wherein the extractant is one or more of tributyl phosphate and 2-ethylhexyl mono-2-ethylhexyl phosphate, and the diluent is sulfonated kerosene or industrial kerosene; the mass ratio of the extractant to the diluent is (4-40): (60-96).

6. The method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution according to claim 1, characterized in that: In step S4, the volume ratio of the organic phase used in the extraction to the gallium acid solution is 1:(0.5-15), and the number of stages of the extraction is 3-8.

7. The method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution according to claim 1, characterized in that: In step S5, the stripping agent used in the stripping is one or more of sodium hydroxide, ammonia water, ammonium chloride, sodium carbonate, sodium bicarbonate, and pure water; The volume ratio of the gallium-rich organic phase to the stripping agent is (1-7): (1-3), and the stripping time is 5-30 min.

8. The method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution according to claim 1, characterized in that: In step S6, the pH of the second precipitation reaction is 5-7, the reaction temperature is 40-95° C., and the reaction time is 30-120 min.

9. The method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution according to claim 1, characterized in that: In step S7, the conditions for the alkaline dissolution include: the concentration of the alkaline solution is 2.5-4 mol / L, the liquid-solid ratio of the alkaline solution to the gallium hydroxide precipitate is (3-7): 1 mL / g; the temperature of the alkaline dissolution is 40-70°C, and the alkaline dissolution time is 1-4 h.

10. The method for recovering gallium from vanadium-titanium magnetite converter slag acid leaching solution according to claim 1, characterized in that: The method further comprises regenerating the lean organic phase obtained in step S5 to obtain a regenerated organic phase, and recycling the regenerated organic phase for use in the extraction step.

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