Process for extracting gallium from vanadium extraction converter dust

Abstract

The present application relates to the field of rare metal smelting and gallium extraction, and particularly relates to a gallium extraction process for vanadium extraction converter dust. The gallium extraction process provided by the present application realizes carbon-free emission in iron smelting of secondary resources, directly recovers gallium with lye, avoids the introduction of high-pollution organic matter, and simultaneously realizes effective separation of gallium, iron and vanadium. The gallium extraction process is short, has no acid leaching and extraction process, is shortened by at least half compared with other processes, avoids the introduction of organic components into the gallium recovery system by extraction or ion exchange resin, and has good impurity removal effect. The gallium extraction process of the present application can finally extract gallium from gallium-containing secondary resources with a high recovery rate, the recovery rate is as high as 95%, and the extracted gallium meets the national standard of industrial gallium. The by-products produced simultaneously can be reused in the vanadium extraction and iron smelting system to obtain by-products with high economic value. The excess chloride salt in the system can also be collected regularly. Since the chloride salt is relatively pure, it can be directly reused in the first step of the gallium extraction process, that is, the mixing stage with the vanadium extraction converter dust.

Description

Technical Field

[0001] This invention relates to the field of rare metal smelting and gallium extraction, specifically a gallium extraction process from vanadium converter dust. Background Technology

[0002] Gallium (Ga) is a rare and dispersed metal with extremely low abundance in the Earth's crust. It rarely exists as an independent mineral, primarily occurring as a byproduct of bauxite, lead-zinc ore, and coal mines, or as an isomorphous element within mineral crystal lattices. With the global energy transition and the rapid development of high-tech industries, gallium's strategic importance is increasingly prominent, and technological innovation in its extraction and resource recycling have become a global focus. Gallium is a core material for third-generation semiconductors (gallium nitride GaN, gallium arsenide GaAs), solar cells (copper indium gallium selenide CIGS), LED lighting, and 5G communication devices. Globally, 90% of primary gallium is produced as a byproduct of bauxite smelting, but major producing countries such as China and Germany face challenges such as declining ore grades and rising extraction costs. Therefore, secondary resources have become an important supplement.

[0003] Traditional gallium extraction relies on an acid / alkali leaching-solvent extraction-electrolysis process, but faces significant challenges: low selectivity and high environmental costs. Gallium shares similar chemical properties with elements such as aluminum, iron, and zinc, resulting in low separation efficiency, and traditional organic extractants are prone to causing pollution. Therefore, the international academic community is focusing on green extraction technologies: bioleaching, ionic liquid extraction, etc., aiming to reduce energy consumption and pollution, but these methods are relatively expensive.

[0004] The Panxi region has a wide variety of valuable metals. Gallium is associated with elements such as V, Fe, and Ti in Panxi minerals. From the 1970s to the present, gallium extraction research has mainly used vanadium extraction tailings as raw material. However, due to the complex composition of vanadium extraction tailings, direct acid leaching has a low leaching rate, high acid consumption, and generates a large amount of unusable byproducts. Furthermore, the entire process is very long, so this route has not actually been put into industrial production. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a gallium extraction process for vanadium converter dust. The gallium extraction process provided by the present invention can extract gallium from gallium-containing secondary resources with a high recovery rate, and the extracted gallium meets the national standard for industrial gallium.

[0006] This invention provides a gallium extraction process for vanadium converter dust, comprising the following steps:

[0007] The mixture of vanadium converter flue dust and chloride salt is calcined to obtain a slag-liquid mixture and gallium chloride volatiles. The gallium chloride volatiles are collected in an alkaline solution and then electrolyzed to obtain metallic gallium.

[0008] The calcination temperature is 1000℃~1300℃, and the vacuum degree of the calcination is 1 Pa~100 Pa.

[0009] This invention first calcines a mixture of vanadium extraction converter dust and chloride salts. Specifically, the mixture of vanadium extraction converter dust and chloride salts is obtained by mixing and molding vanadium extraction converter dust and chloride salts. More specifically, dried vanadium extraction converter dust and chloride salts are mixed and then molded to obtain the mixture of vanadium extraction converter dust and chloride salts; the molding includes pelletizing or pressing. The mass amount of chloride salts used in this invention is 0.5 to 2 times the mass amount of vanadium extraction converter dust. The chloride salts used in this invention are selected from one or more of sodium chloride, potassium chloride, and ammonium chloride. The diameter of the mixture of vanadium extraction converter dust and chloride salts used in this invention is 2 cm to 12 cm.

[0010] This invention involves calcining a mixture of vanadium extraction converter dust and chloride salts into a molding material. The calcination temperature is 1000℃~1300℃, and the vacuum degree during calcination is 1 Pa~100 Pa. The calcination time depends on the amount of pellets added; for 1 t of the mixture of vanadium extraction converter dust and chloride salts into a molding material, the calcination time is 2 h~10 h. The calcination process described in this invention yields a slag-liquid mixture and gallium chloride volatiles. Specifically, during the calcination process, the mixed molding material of vanadium extraction converter dust and chloride salts melts. Volatile metal elements first volatilize to the condensation zone at a low temperature of 400℃~600℃, while the unvolatilized material forms a slag layer and a molten liquid. The molten liquid includes pig iron, chloride salts, and gallium. As the temperature rises to 800℃~950℃, the chloride salts in the molten liquid decompose and slowly release chlorine gas, which reacts with the gallium in the molten liquid to generate gallium chloride. The calcination temperature is controlled at 1000℃~1300℃ to generate a large amount of gallium chloride. The gallium chloride volatilizes under vacuum and enters the next gallium extraction process. The main component of the molten liquid after the reaction is pig iron. Therefore, the slag-liquid mixture obtained by calcination includes molten pig iron and a slag layer. The slag layer can be used in the vanadium extraction process, while the molten pig iron can be used as molten iron in the steelmaking process.

[0011] The vanadium extraction converter flue dust described in this invention specifically refers to waste from the vanadium-titanium magnetite beneficiation process; the gallium content of the vanadium extraction converter flue dust is 200 g / t to 500 g / t. More specifically, disregarding the gallium content, the vanadium extraction converter flue dust of this invention also includes 85 wt% to 92 wt% Fe2O3, 1 wt% to 3 wt% SiO2, 1 wt% to 5 wt% ZnO, and less than 10 wt% of other impurities. That is, the remaining material after subtracting the gallium content from the vanadium extraction converter flue dust of this invention includes 85 wt% to 92 wt% Fe2O3, 1 wt% to 3 wt% SiO2, 1 wt% to 5 wt% ZnO, and less than 10 wt% of other impurities; wherein, the other impurities include Na2O, MgO, CaCO3, Al2O3, TiO2, V2O5, Cr2O3, PbO, CuO, NiO, chlorides, and sulfides. In some embodiments of the present invention, the remaining material after subtracting the gallium content from the vanadium extraction converter flue dust comprises 85 wt%~92 wt% Fe2O3, 1 wt%~3 wt% SiO2, 1 wt%~5 wt% ZnO, and less than 10 wt% of other impurities, including 0.5 wt%~1.5 wt% Na2O, 0.5 wt%~1.5 wt% MgO, 0.5 wt%~2 wt% CaCO3, 0.1 wt%~0.5 wt% Al2O3, 0.1 wt%~0.5 wt% TiO2, 0.5 wt%~1.5 wt% V2O5, 0.1 wt%~1 wt% Cr2O3, 0.5 wt%~1.5 wt% PbO, 0.1 wt%~0.5 wt% CuO, and 0.1 wt%~0.5 wt% CuO. The raw material of the vanadium extraction converter flue gas described in this invention is unique, with a high gallium content. In the slag-liquid mixture obtained by calcining the mixed molding material of the vanadium extraction converter flue gas and chloride salts described in this invention, the metallic iron in the pig iron is above 95 wt%, and the slag layer is mainly composed of oxides such as Si, Mg, Ca, V, and Cr, with a total content of less than 5 wt%. Volatile metal elements such as lead and zinc volatilize to the condensation zone first in the low-temperature section (400℃~600℃). Since the content of lead and zinc is relatively low, only periodic cleaning of the condensation zone is required.

[0012] This invention involves calcining a mixture of vanadium converter flue dust and chloride salts to obtain a slag-liquid mixture and gallium chloride volatiles. The gallium chloride volatiles are then collected in an alkaline solution and electrolyzed to obtain metallic gallium. Specifically, the gallium chloride volatiles are collected in an alkaline solution with a pH of 10.0–14.0 until the gallium concentration in the alkaline solution reaches 20 g / L, at which point the alkaline solution is replaced with fresh alkaline solution for gallium collection. More specifically, the gallium chloride volatiles are dissolved in an alkaline solution to obtain a gallium-rich alkaline solution. An appropriate amount of calcium oxide or sodium sulfide is added to the gallium-rich alkaline solution to remove impurities. After impurity removal, the gallium-rich alkaline solution is electrolyzed to obtain metallic gallium.

[0013] The present invention also includes vanadium extraction from the slag layer in the slag-liquid mixture and steelmaking from the molten pig iron in the slag-liquid mixture. The slag layer in the slag-liquid mixture can be fed into a vanadium extraction system, while the molten pig iron in the slag-liquid mixture can be directly fed into the steelmaking process, offering significant economic value.

[0014] This invention provides a gallium extraction process from vanadium-containing converter flue dust. The gallium extraction process provided by this invention achieves carbon-free iron smelting from secondary resources, while directly recovering gallium using alkaline solution, avoiding the introduction of highly polluting organic matter, and simultaneously achieving effective separation of gallium, iron, and vanadium. The gallium extraction process is short, without acid leaching or extraction processes, shortening the process by at least half compared to other processes. It avoids the introduction of organic components into the gallium recovery system through extraction or ion exchange resins, resulting in excellent impurity removal. The gallium extraction process provided by this invention can ultimately extract gallium from gallium-containing secondary resources with a high recovery rate of up to 95%, and the extracted gallium meets the national industrial gallium standards. Simultaneously, the generated byproducts can be recycled into the vanadium extraction and iron smelting systems to obtain byproducts of high economic value. Excess chloride salts in the system can also be collected periodically; because the chloride salts are relatively pure, they can be directly recycled to the first stage of the gallium extraction process, where they are mixed with the vanadium-containing converter flue dust, offering significant economic value. Attached Figure Description

[0015] Figure 1 A flowchart of the gallium extraction process for gallium-containing secondary resources provided by the present invention. Detailed Implementation

[0016] This invention discloses a gallium extraction process for vanadium converter flue dust. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to implement and apply the technology of this invention.

[0017] like Figure 1 As shown, Figure 1 A flowchart of the gallium extraction process for gallium-containing secondary resources provided by the present invention.

[0018] The present invention will be further described below with reference to the embodiments:

[0019] Example 1

[0020] The secondary gallium-enriched resources mainly consist of 85 wt% Fe₂O₃, 3 wt% SiO₂, 5 wt% ZnO, with the remainder being 1 wt% Na₂O, 0.7 wt% MgO, 1.4 wt% CaCO₃, 0.3 wt% Al₂O₃, 0.1 wt% TiO₂, 0.6 wt% V₂O₅, 0.4 wt% Cr₂O₃, 0.9 wt% PbO, 0.2 wt% CuO, 0.1 wt% NiO, 0.6 wt% chloride, and 0.7 wt% sulfide. The gallium content in the secondary resources is approximately 200 g / t.

[0021] The first step is to dry the gallium-containing secondary resource. The dried material is then mixed with sodium chloride, with the chloride salt added at twice the amount of the secondary resource solids. After mixing, the mixture is pelletized, with each pellet having a diameter of 12 cm.

[0022] In the second step, the pellets are directly fed into a vacuum furnace, where the vacuum level is controlled at 1 Pa and the temperature at 1000°C. o C, calcined in a constant temperature zone for 10 hours. After calcination, a molten pig iron and a slag layer are formed. The molten pig iron contains 96 wt% metallic iron, and the slag layer mainly consists of oxides of Si, Mg, Ca, V, Cr, etc., with a total content of less than 4 wt%. Volatile metals such as lead and zinc are present at 400°C. The chlorine initially evaporates into the condensation zone. As the temperature rises to 800℃, the chloride salt decomposes and slowly releases chlorine gas, which reacts with gallium in the pig iron to form gallium chloride, which then evaporates into the vacuum.

[0023] The third step is to collect the volatilized gallium chloride in an alkaline solution. The pH of the alkaline solution needs to be controlled within the range of 10.0 to 14.0 until the concentration of gallium in the alkaline solution reaches 20 g / L. Then, a new alkaline solution needs to be used to collect the gallium.

[0024] The fourth step involves adding appropriate amounts of calcium oxide, sodium sulfide, and other substances to the gallium-rich alkaline solution to remove impurities from the gallium-rich electrolyte. After impurity removal, the gallium-rich solution is electrolyzed. During the electrolysis process, the gallium recovery rate is 95%, ultimately yielding industrial gallium that conforms to GB / T 1475-2022.

[0025] Example 2

[0026] The secondary gallium-enriched resources mainly consist of 92 wt% Fe₂O₃, 1 wt% SiO₂, 1 wt% ZnO, with the remainder being 1 wt% Na₂O, 0.6 wt% MgO, 0.5 wt% CaCO₃, 0.2 wt% Al₂O₃, 0.2 wt% TiO₂, 0.6 wt% V₂O₅, 0.6 wt% Cr₂O₃, 0.7 wt% PbO, 0.2 wt% CuO, 0.1 wt% NiO, 0.3 wt% chloride, and 1 wt% sulfide. The gallium content in the secondary resources is approximately 500 g / t.

[0027] The first step of this invention is to dry the gallium-containing secondary resource. The dried material is then mixed with sodium chloride and potassium chloride, with the chloride salt added at 0.5 times the amount of the secondary resource solid. After mixing, the mixture is compressed into tablets with a diameter of 2 cm.

[0028] In the second step, the pellets are directly fed into a vacuum furnace, where the vacuum level is controlled at 100 Pa and the temperature at 1300℃, and calcined for 2 hours. After calcination, molten pig iron and a slag layer are formed. The molten pig iron contains more than 98 wt% metallic iron, while the slag layer mainly consists of oxides of Si, Mg, Ca, V, Cr, etc., with a total content of less than 2 wt%. Volatile metals such as lead and zinc volatilize to the condensation zone at a low temperature of 600℃. As the temperature rises to 950℃, chloride salts decompose slowly, releasing chlorine gas, which reacts with gallium in the pig iron to form gallium chloride, which then volatilizes under vacuum.

[0029] The third step is to collect the volatilized gallium chloride in an alkaline solution. The pH of the alkaline solution needs to be controlled within the range of 10.0-14.0 until the concentration of gallium in the alkaline solution reaches 20 g / L. Then, a new alkaline solution needs to be used to collect the gallium.

[0030] The fourth step involves adding appropriate amounts of calcium oxide, sodium sulfide, and other substances to the gallium-rich alkaline solution to remove impurities from the gallium-rich electrolyte. After impurity removal, the gallium-rich solution is electrolyzed. During the electrolysis process, the gallium recovery rate is 94%, ultimately yielding industrial gallium that conforms to GB / T 1475-2022.

[0031] Comparative Example 1

[0032] The secondary gallium-enriched resources mainly consist of 85 wt% Fe₂O₃, 3 wt% SiO₂, 5 wt% ZnO, with the remainder being 1 wt% Na₂O, 0.7 wt% MgO, 1.4 wt% CaCO₃, 0.3 wt% Al₂O₃, 0.1 wt% TiO₂, 0.6 wt% V₂O₅, 0.4 wt% Cr₂O₃, 0.9 wt% PbO, 0.2 wt% CuO, 0.1 wt% NiO, 0.6 wt% chloride, and 0.7 wt% sulfide. The gallium content in the secondary resources is approximately 200 g / t.

[0033] The first step is to dry the gallium-containing secondary resource. The dried material is then mixed with sodium chloride, with the chloride added at three times the amount of the secondary resource solids. After mixing, the mixture is pelletized, with each pellet having a diameter of 12 cm.

[0034] In the second step, the pellets are directly fed into a vacuum furnace, where the vacuum level is controlled at 1 Pa and the temperature at 1000℃, and calcined in a constant-temperature zone for 10 hours. After calcination, molten pig iron and a slag layer are formed. The molten pig iron contains 96 wt% metallic iron, and the slag layer mainly consists of oxides of Si, Mg, Ca, V, Cr, etc., with a total content of less than 4 wt%. Volatile metals such as lead and zinc volatilize to the condensation zone first at 400℃. As the temperature rises to 800℃, chloride decomposes slowly, releasing chlorine gas, which reacts with gallium in the pig iron to form gallium chloride. Gallium chloride volatilizes under vacuum, but due to the excessive amount of sodium chloride added, some sodium chloride volatilizes along with gallium chloride. During the collection of gallium chloride, due to the excessive salt content in the alkaline solution, salt precipitates when the gallium concentration in the alkaline solution does not reach 20 g / L. The precipitation of salt carries away some gallium, thus affecting the gallium recovery rate. After impurity removal, the gallium recovery rate is only about 80%.

[0035] Comparative Example 2

[0036] The secondary gallium-enriched resources mainly consist of 92 wt% Fe₂O₃, 1 wt% SiO₂, 1 wt% ZnO, with the remainder being 1 wt% Na₂O, 0.6 wt% MgO, 0.5 wt% CaCO₃, 0.2 wt% Al₂O₃, 0.2 wt% TiO₂, 0.6 wt% V₂O₅, 0.6 wt% Cr₂O₃, 0.7 wt% PbO, 0.2 wt% CuO, 0.1 wt% NiO, 0.3 wt% chloride, and 1 wt% sulfide. The gallium content in the secondary resources is approximately 500 g / t.

[0037] The first step of this invention is to dry the gallium-containing secondary resource. The dried material is then mixed with sodium chloride and potassium chloride, with the chloride salt added at 0.5 times the amount of the secondary resource solid. After mixing, the mixture is compressed into tablets with a diameter of 2 cm.

[0038] In the second step, the pellets are directly fed into a vacuum furnace, where the vacuum level is controlled at 200 Pa and the temperature at 1300℃, and calcined for 2 hours. After calcination, molten pig iron and a slag layer are formed. The molten pig iron contains approximately 80 wt% metallic iron, while the slag layer mainly consists of oxides of Fe, Si, Mg, Ca, V, Cr, etc., with a total content of approximately 20 wt%. Meanwhile, the chloride salts are not fully decomposed, and only a small amount of chlorine gas is generated, failing to meet the conditions for gallium chloride formation.

[0039] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A gallium extraction process for vanadium-extraction converter dust, characterized in that, Includes the following steps: The mixture of vanadium converter flue dust and chloride salt is calcined to obtain a slag-liquid mixture and gallium chloride volatiles. The gallium chloride volatiles are dissolved in alkali and then electrolyzed to obtain metallic gallium. The chloride salt is selected from one or more of sodium chloride and potassium chloride. The mass amount of the chloride salt is 0.5 to 2 times the mass amount of the vanadium extraction converter dust. The calcination temperature is 1000℃~1300℃, and the vacuum degree of the calcination is 1 Pa~100 Pa; The alkaline dissolution is carried out at a pH of 10.0 to 14.

0.

2. The gallium extraction process according to claim 1, characterized in that, The diameter of the mixed molding material of vanadium extraction converter dust and chloride salt is 2 cm to 12 cm.

3. The gallium extraction process according to claim 1, characterized in that, Based on 1 t of the mixed molding material of vanadium extraction converter dust and chloride salt, the calcination time is 2 h to 10 h.

4. The gallium extraction process according to claim 1, characterized in that, The gallium content of the vanadium extraction converter flue dust is 200 g / t to 500 g / t.

5. The gallium extraction process according to claim 4, characterized in that, Regardless of the gallium content, the vanadium extraction converter flue dust also includes 85 wt%~92 wt% Fe2O3, 1 wt%~3 wt% SiO2, 1 wt%~5 wt% ZnO and less than 10 wt% of other impurities.

6. The gallium extraction process according to claim 5, characterized in that, The other impurities include Na2O, MgO, CaCO3, Al2O3, TiO2, V2O5, Cr2O3, PbO, CuO, NiO, chlorides, and sulfides.

7. The gallium extraction process according to claim 1, characterized in that, It also includes extracting vanadium from the slag layer in the slag-liquid mixture and smelting the molten pig iron in the slag-liquid mixture into steel.

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