Production method for recycling gallium from lime slag in acid-process gallium production

Abstract

The invention discloses a production method for recycling gallium from lime slag in acid-process gallium production in the technical field of acid-process gallium production, which comprises the following steps: S1, adding lime into a mixed solution treated in the third step for heating, conveying the mixed solution to a diaphragm filter press through an impurity removal pump for solid-liquid separation, leaving the lime slag in the diaphragm filter press, separating the filtrate to the fifth step of the original process; s2, adding water and caustic soda liquid into the lime slag scattering device, adding the lime slag into the lime slag scattering device, and heating for stirring reaction; solid and liquid obtained after reaction of the lime slag scattering device are conveyed into the diaphragm filter press through the circulating pump to be subjected to solid-liquid separation again, residual lime slag is left in the diaphragm filter press, and filtrate is separated and recycled into a filtrate tank to be subjected to gallium recovery. According to the scheme, water and liquid caustic soda are added into lime slag treated as solid waste for reaction in a lime slag scattering device, and gallium in the lime slag is extracted and recycled.

Description

Technical Field

[0001] The invention relates to the technical field of acid-process gallium production, and in particular to a method for recovering gallium from lime slag during acid-process gallium production. Background Art

[0002] In the impurity removal process of acid gallium production, the desorption liquid after analysis in the acid adsorption tower is mainly composed of sulfuric acid and gallium sulfate. Gallium sulfate is a colorless and transparent liquid that can be mixed with sulfuric acid in any ratio. The gallium content in this solution is low, only about 2.5g / L; the impurities Fe, Cu, and Zn are high, so it needs to be concentrated and impurities removed. The main process flow is summarized as follows: The first step is to add an appropriate amount of sodium hydroxide solution to neutralize to a specified pH value to generate a mixed solution of sodium sulfate and gallium hydroxide, wherein gallium hydroxide is a white insoluble substance; the second step is to prepare a certain proportion of flocculant solution, and the flocculant solution and the neutralized mixed solution are simultaneously input into a horizontal centrifuge in a certain proportion to achieve solid-liquid separation of gallium hydroxide and impurities such as sodium sulfate and water to obtain concentrated gallium hydroxide; the third step is to add an appropriate amount of sodium hydroxide solution to the concentrated gallium hydroxide, and heat the sodium hydroxide and gallium hydroxide to completely react to produce sodium gallate, forming a mixed solution of sodium gallate and sodium hydroxide, and the sodium gallate is a colorless and transparent solution; the fourth step is to add lime and heat to 100°C to fully react impurities such as vanadium in the solution, and the solution is transported to a filter press to separate the reacted lime slag and the solution, and the solution enters the next process flow to achieve the first impurity removal of the solution, and the lime slag is disposed of as solid waste outsourced; the fifth step is to add a certain amount of sodium sulfide nonahydrate to the solution after lime impurity removal, and the solution is transported to a filter press to remove Fe 3+ , CU 2+ 、Zn + , Pb + , Hg + The metal ions are removed to separate the sulfide and the solution after the reaction. The solution enters the next process to achieve the second impurity removal of the solution. Finally, the solution is transported to electrolysis.

[0003] In the above-mentioned "fourth step", the lime slag produced is sold externally and outsourced for disposal as solid waste, with about 100 tons of lime slag produced each year. Firstly, there is no automation and the labor intensity is high; secondly, the lime slag contains a high gallium content and high water content, about 35%. If it is not recycled, it will cause certain economic losses. Summary of the invention

[0004] The present invention aims to provide a method for recovering gallium from lime slag in the production of gallium by an acid process, so as to recover gallium from the lime slag.

[0005] In order to achieve the above object, the present invention provides the following technical solutions: A method for recovering gallium from lime slag in the production of gallium by the acid process comprises the following steps: S1, lime is added to the mixed solution after the treatment in the third step of the original process for heating, and the solution is transported to the membrane filter press through the impurity removal pump for solid-liquid separation, the lime residue remains in the membrane filter press, and the filtrate is separated to the fifth step of the original process; S2, adding water and liquid alkali to the lime slag dispersing device, adding the lime slag to the lime slag dispersing device, heating and stirring the reaction; transporting the solid and liquid after the reaction of the lime slag dispersing device to the diaphragm filter press through a circulating pump for solid-liquid separation again, leaving the residual lime slag in the diaphragm filter press, and separating and recovering the filtrate to the filtrate tank for gallium recovery; S3, add water to the lime slag dispersing device again, add the lime slag remaining in the membrane filter press into the lime slag dispersing device again, start the lime slag dispersing device for stirring reaction, and start the circulation pump to transport the mixed solution of lime slag and water to the sewage tank.

[0006] Working principle and beneficial effects of the present invention: In this plan, lime slag that is outsourced for solid waste disposal is treated by adding water and liquid alkali in a lime slag disintegration device to react, and the gallium in the lime slag is extracted and recovered.

[0007] Optimally, 80 kg of lime is added to the S1 and then heated to 100°C.

[0008] Optimally, the concentration of the liquid caustic soda is 450 g / L.

[0009] Optimally, the S2 is heated to 85°C to 95°C during the stirring and heating reaction, and the reaction is carried out for 1 hour.

[0010] Optimally, compressed air is introduced into S1 and S3 to squeeze the lime slag remaining in the membrane filter press, so that the attached water is reduced to ≤20%.

[0011] Optimally, the lime slag dispersing device adds 3m³ of water. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a process flow chart of a method for recovering gallium from lime slag in the production of gallium by the acid process of the present invention; Figure 2 This is a statistical chart of impurity content in lime slag from 2017 to 2023. DETAILED DESCRIPTION

[0013] The following is further described in detail through specific implementation methods: The main process flow in the prior art is summarized as follows: The first step is to add an appropriate amount of sodium hydroxide solution to neutralize to a specified pH value to generate a mixed solution of sodium sulfate and gallium hydroxide, wherein gallium hydroxide is a white insoluble substance; the second step is to prepare a certain proportion of flocculant solution, and the flocculant solution and the neutralized mixed solution are simultaneously input into a horizontal centrifuge in a certain proportion to achieve solid-liquid separation of gallium hydroxide and impurities such as sodium sulfate and water to obtain concentrated gallium hydroxide; the third step is to add an appropriate amount of sodium hydroxide solution to the concentrated gallium hydroxide, and heat the sodium hydroxide and gallium hydroxide to completely react to produce sodium gallate, forming a mixed solution of sodium gallate and sodium hydroxide, and the sodium gallate is a colorless and transparent solution; the fourth step is to add lime and heat to 100°C to fully react impurities such as vanadium in the solution, and the solution is transported to a filter press to separate the reacted lime slag and the solution, and the solution enters the next process flow to achieve the first impurity removal of the solution, and the lime slag is disposed of as solid waste outsourced; the fifth step is to add a certain amount of sodium sulfide nonahydrate to the solution after lime impurity removal, and the solution is transported to a filter press to remove Fe 3+ , CU 2+ 、Zn + , Pb + , Hg + The metal ions are removed to separate the sulfide and the solution after the reaction. The solution enters the next process to achieve the second impurity removal of the solution. Finally, the solution is transported to electrolysis.

[0014] Lime slag is treated as solid waste by outsourcing, resulting in a high gallium content in lime slag and high water content, about 35%. According to the test, the gallium content of lime slag from 2017 to 2023 is 2.32% (see Figure 2 ), if not recycled, it will cause certain economic losses.

[0015] Embodiment, a method for recovering gallium from lime slag in the production of gallium by acid process, comprising the following steps: The fourth step of the above process is changed to adding 80 kg of lime, and then heating to 100°C to make the impurities such as vanadium in the solution fully react, and the solution is transported to the membrane filter press through P201, the lime slag remains in the membrane filter press, and the filtrate is separated to the original process TK202, and enters the fifth step of the above process. Compressed air is introduced to squeeze the lime slag left in the membrane filter press to reduce the attached water to ≤20%. Add 3m³ of water and 1m³ of liquid caustic soda with a concentration of 450g / L to the lime slag dispersing device TK2201, start the stirring of the dispersing device, unload the lime slag from the membrane filter press, and after the slag unloading is completed, add the lime slag to the lime slag dispersing device and heat it to 85℃~95℃, react for 1 hour, start the circulation pump P2201 to transport the solid and liquid to the membrane filter press, and the lime slag remains in the membrane filter press. The filtrate is separated and recovered to the filtrate tank TK2202, and compressed air is introduced to squeeze the lime slag remaining in the membrane filter press to reduce the attached water to ≤20%. The filtrate recovered to the filtrate tank TK2202 is recovered to the original TK108 tank through P2202 to achieve the purpose of recovering gallium. Add 3m³ of water to the lime slag dispersing device TK2201 again, start the stirring of the dispersing device, unload the lime slag from the diaphragm filter press, put the lime slag into the lime slag dispersing device, disperse and react for 1 hour, start the circulation pump P2201, and transport the mixed solution of lime slag and water to the original TK106 sewage tank.

Claims

1. A method for recovering gallium from lime slag in the production of gallium by acid process, characterized in that: The following steps are involved: S1, lime is added to the mixed solution after the treatment in the third step of the original process for heating, and the solution is transported to the membrane filter press through the impurity removal pump for solid-liquid separation, the lime residue remains in the membrane filter press, and the filtrate is separated to the fifth step of the original process; S2, adding water and liquid alkali to the lime slag dispersing device, adding the lime slag to the lime slag dispersing device, heating and stirring the reaction; transporting the solid and liquid after the reaction of the lime slag dispersing device to the diaphragm filter press through a circulating pump for solid-liquid separation again, leaving the residual lime slag in the diaphragm filter press, and separating and recovering the filtrate to the filtrate tank for gallium recovery; S3, add water to the lime slag dispersing device again, add the lime slag remaining in the membrane filter press into the lime slag dispersing device again, start the lime slag dispersing device for stirring reaction, and start the circulation pump to transport the mixed solution of lime slag and water to the sewage tank.

2. The method for recovering gallium from lime slag in acid gallium production according to claim 1, characterized in that: 80 kg of lime was added to the S1 and then heated to 100°C.

3. The method for recovering gallium from lime slag in acid gallium production according to claim 2, characterized in that: The concentration of the liquid caustic soda is 450 g / L.

4. The method for recovering gallium from lime slag in acid gallium production according to claim 3, characterized in that: The S2 is heated to 85°C to 95°C during the stirring and heating reaction and reacted for 1 hour.

5. The method for recovering gallium from lime slag in acid gallium production according to claim 4, characterized in that: The compressed air is introduced into S1 and S3 to squeeze the lime slag remaining in the membrane filter press, so that the attached water is reduced to ≤20%.

6. The method for recovering gallium from lime slag in acid gallium production according to any one of claims 2 to 5, characterized in that: The lime slag dispersing device adds 3m³ of water.

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