Method for rapidly and efficiently removing magnesium from zinc hydrometallurgy leaching solution

Abstract

The invention discloses a method for rapidly and efficiently removing magnesium from a zinc hydrometallurgy leaching solution. The method comprises the following steps: firstly, adding sodium fluoride and zinc fluoride into pure water, and stirring to obtain precipitant slurry; adding a zinc-magnesium mixed solution into the composite precipitant slurry, and carrying out solid-liquid separation after precipitation to obtain a magnesium precipitate and a zinc-containing filtrate; according to the method, the zinc-magnesium mixed solution is reversely added into the sodium fluoride and zinc fluoride precipitant, so that the filtering speed of solid-liquid separation can be remarkably increased, meanwhile, it can be guaranteed that magnesium ions have a high precipitation rate, efficient magnesium removal of the zinc hydrometallurgy leaching solution is achieved, and the method is suitable for large-scale popularization and application. Therefore, the problems of difficult filtration and insufficient magnesium precipitation rate caused by a single precipitator and a precipitator forward adding method are solved, the whole process is mild in operation condition, the operation can be completed under normal pressure and at the temperature close to the temperature of the zinc hydrometallurgy leaching solution, and the process is suitable for industrial popularization and has better industrial application value.

Description

Technical Field

[0001] This invention relates to the field of zinc hydrometallurgy, specifically to a method for rapid and efficient removal of magnesium from zinc leaching solutions in hydrometallurgical processes. Background Technology

[0002] Zinc, as an important non-ferrous metal resource, has wide applications in metallurgy, chemical industry, and energy. Hydrometallurgical zinc smelting, currently the most common method for zinc extraction, has the advantages of low energy consumption and low pollution. However, during acid leaching, magnesium ions dissolve along with zinc and enter the solution, negatively impacting electrodeposition efficiency and overall sustainability. Therefore, magnesium removal in hydrometallurgical zinc smelting solution systems is of great significance.

[0003] In production, magnesium removal is typically achieved by adding sodium fluoride as a precipitant to the leachate. During this process, fluoride ions with high diffusion rates rapidly enter the magnesium-rich system and quickly combine with more magnesium ions over a large area to form numerous fine crystal nuclei. This hinders crystal growth, ultimately resulting in fine-grained precipitates that are difficult to filter. Therefore, existing methods using the forward addition of precipitants result in slow filtration and low magnesium removal rates. Furthermore, using sodium fluoride alone as a precipitant produces fine magnesium fluoride particles with poor flocculation and slow filtration. Additionally, patent CN109592706A describes a magnesium removal method using hydrofluoric acid as a precipitant; however, this method introduces highly corrosive and toxic hydrofluoric acid, posing significant safety and environmental risks. Patent CN115959700A describes a method for first preparing hexagonal zinc fluoride and then using this material for magnesium removal; however, this method requires strict control of various conditions, including the timing of the addition of basic zinc carbonate, making preparation difficult and the process complex.

[0004] Therefore, there is an urgent need to develop a method that can improve the filtration speed of solid-liquid separation, ensure a high precipitation rate of magnesium ions, and achieve efficient magnesium removal from wet zinc smelting leachate. Summary of the Invention

[0005] To address the aforementioned deficiencies in the prior art, this invention provides a rapid and efficient method for removing magnesium from wet zinc smelting leaching solutions. By adding sodium fluoride and zinc fluoride precipitants in reverse to a zinc-magnesium mixed solution, magnesium ions slowly diffuse in a fluoride-rich environment, allowing crystal nuclei to grow continuously within a small region, generating larger precipitate particles. This significantly improves the filtration performance of solid-liquid separation while ensuring a high magnesium ion precipitation rate, achieving highly efficient magnesium removal from wet zinc smelting leaching solutions. This invention, using a combination of sodium fluoride and zinc fluoride as precipitants and employing a reverse addition method, balances the driving force of the precipitation reaction with the magnesium precipitation rate, overcoming the filtration difficulties and insufficient magnesium precipitation rates caused by single precipitants and forward addition methods. The reaction process can be carried out under normal pressure, with mild reaction conditions and a reaction temperature similar to that of the wet zinc smelting leaching solution. Its operation is simple, suitable for industrial application, and has excellent application prospects.

[0006] To achieve the above technical effects, the following technical solution is adopted: A method for rapid and efficient removal of magnesium from wet zinc smelting leaching solutions, the method comprising the following steps: Step S1: Add fluoride to pure water and stir thoroughly to obtain a fluoride precipitant slurry; Step S2: Add zinc-magnesium mixed solution to the fluoride precipitant slurry obtained in step S1, and carry out the precipitation reaction fully under stirring and heating conditions; Step S3: After step S2, solid-liquid separation is performed to obtain magnesium precipitate and zinc-containing filtrate; Furthermore, the fluoride is a mixture of sodium fluoride and zinc fluoride; Furthermore, the molar ratio of fluoride ions in the fluoride to magnesium ions in the zinc-magnesium mixed solution is 2:1-4:1; Furthermore, the molar ratio of fluoride ions in the fluoride to magnesium ions in the zinc-magnesium mixed solution is 4:1. Furthermore, in step S1, the molar ratio of sodium fluoride to zinc fluoride is 1:5-10:1; Furthermore, in step S1, the molar ratio of sodium fluoride to zinc fluoride is 6:1; Furthermore, in step S2, the volume ratio of the zinc-magnesium mixed solution to the fluoride precipitant slurry is 5:1-10:1; Furthermore, in step S2, the zinc ion content in the zinc-magnesium mixed solution is 130-150 g / L, and the magnesium ion content is 10-15 g / L; Furthermore, in step S2, the reaction temperature is 60-80℃ and the reaction time is 15-60 min; Furthermore, in step S2, the reaction temperature is 70°C and the reaction time is 30 min.

[0007] The beneficial effects of this invention are as follows: This invention significantly improves the filtration speed of solid-liquid separation by adding sodium fluoride and zinc fluoride precipitants in reverse to a zinc-magnesium mixed solution, while also achieving remarkable magnesium removal. By adding sodium fluoride and zinc fluoride precipitants in reverse to the zinc-magnesium mixed solution, magnesium ions diffuse slowly in a fluoride-rich environment, and crystal nuclei grow continuously within a small area, generating larger precipitate particles. This significantly improves the filtration speed of solid-liquid separation and ensures a high magnesium precipitation rate, thus achieving efficient magnesium removal from wet zinc smelting leaching solutions. This invention uses a combination of sodium fluoride and zinc fluoride as precipitants, combined with a reverse addition method, to balance the driving force of the precipitation reaction and the magnesium precipitation rate. It overcomes the filtration difficulties and insufficient magnesium precipitation rates caused by single precipitants and forward addition methods. The reaction process can be carried out under normal pressure, with mild reaction conditions and a reaction temperature similar to that of wet zinc smelting leaching solutions. Its operation is simple, suitable for industrial promotion, and has excellent application prospects. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0009] Figure 1 This is a schematic diagram illustrating the rapid and efficient magnesium removal process of wet zinc smelting leaching solution provided in an embodiment of the present invention. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0011] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0012] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0013] In the following examples, unless otherwise specified, all reagents and consumables were purchased from conventional reagent manufacturers in the art; unless otherwise specified, the experimental methods and techniques used are conventional methods and techniques in the art.

[0014] Example 1: Prepare a 50 mL mixed solution of zinc sulfate and magnesium sulfate, wherein the zinc ion concentration in the zinc-magnesium mixture is 150 g / L and the magnesium ion concentration is 15 g / L. Add sodium fluoride and zinc fluoride solids to pure water, wherein the molar ratio of sodium fluoride to zinc fluoride is 6:1. After thorough stirring, a fluoride precipitant slurry is obtained. Add the zinc-magnesium mixture to the fluoride precipitant slurry, wherein the molar ratio of fluoride ions in the fluoride precipitant to magnesium ions in the zinc-magnesium mixture is 4:1, and the volume ratio of the zinc-magnesium mixture to the fluoride precipitant slurry is 5:1. Then, stir the mixture in a water bath at 70°C and 500 rpm for 30 minutes to allow for a complete precipitation reaction. After the reaction, separate the solid and liquid, measure the filtration rate, and calculate the magnesium precipitation rate. See the schematic diagram of the above rapid and efficient magnesium removal process. Figure 1 The filtration rate was found to be 80.4 L / (m²). 2 (·h), the precipitation rate of magnesium is 92.63%.

[0015] Example 2: A 50 mL mixed solution of zinc sulfate and magnesium sulfate was prepared, wherein the zinc ion concentration was 150 g / L and the magnesium ion concentration was 15 g / L. Sodium fluoride and zinc fluoride solids were added to pure water, with a molar ratio of sodium fluoride to zinc fluoride of 6:1. After thorough stirring, a fluoride precipitant slurry was obtained. The zinc-magnesium mixed solution was added to the fluoride precipitant slurry, wherein the molar ratio of fluoride ions in the precipitant to magnesium ions in the zinc-magnesium mixed solution was 2:1, and the volume ratio of the zinc-magnesium mixed solution to the fluoride precipitant slurry was 5:1. The mixture was then stirred in a water bath at 70 °C and 500 rpm for 30 min to allow for complete precipitation. After the reaction, the solid and liquid were separated, the filtration rate was measured, and the magnesium precipitation rate was calculated. The result showed a filtration rate of 83.1 L / (m²). 2 (·h), the precipitation rate of magnesium is 88.47%.

[0016] Example 3: A 50 mL mixed solution of zinc sulfate and magnesium sulfate was prepared, wherein the zinc ion concentration was 150 g / L and the magnesium ion concentration was 15 g / L. Sodium fluoride and zinc fluoride solids were added to pure water, with a molar ratio of sodium fluoride to zinc fluoride of 10:1. After thorough stirring, a fluoride precipitant slurry was obtained. The zinc-magnesium mixed solution was added to the fluoride precipitant slurry, wherein the molar ratio of fluoride ions in the precipitant to magnesium ions in the zinc-magnesium mixed solution was 4:1, and the volume ratio of the zinc-magnesium mixed solution to the fluoride precipitant slurry was 5:1. Subsequently, the mixture was stirred in a water bath at 70 °C and 500 rpm for 30 min to allow for complete precipitation. After the reaction, the solid and liquid were separated, the filtration rate was measured, and the magnesium precipitation rate was calculated. The result showed a filtration rate of 73.2 L / (m²). 2 (·h), the precipitation rate of magnesium is 94.21%.

[0017] Example 4: A 50 mL mixed solution of zinc sulfate and magnesium sulfate was prepared, wherein the zinc ion concentration was 150 g / L and the magnesium ion concentration was 15 g / L. Sodium fluoride and zinc fluoride solids were added to pure water, with a molar ratio of sodium fluoride to zinc fluoride of 1:5. After thorough stirring, a fluoride precipitant slurry was obtained. The zinc-magnesium mixed solution was added to the fluoride precipitant slurry, wherein the molar ratio of fluoride ions in the precipitant to magnesium ions in the zinc-magnesium mixed solution was 4:1, and the volume ratio of the zinc-magnesium mixed solution to the fluoride precipitant slurry was 5:1. The mixture was then stirred in a water bath at 70 °C and 500 rpm for 30 min to allow for complete precipitation. After the reaction, the solid and liquid were separated, the filtration rate was measured, and the magnesium precipitation rate was calculated. The result showed a filtration rate of 80.1 L / (m²). 2 (·h), the precipitation rate of magnesium is 72.71%.

[0018] Comparative Example 1: In Comparative Example 1, zinc fluoride was not added, and the mass of sodium fluoride was equal to the total mass of sodium fluoride and zinc fluoride in Example 1 (i.e., the mass of the fluorine-containing compound in Comparative Example 1 was equivalent to the total mass of the fluorine-containing compound in Example 1). Other experimental conditions were consistent with those in Example 1; the specific conditions and processes are as follows: A 50 mL mixed solution of zinc sulfate and magnesium sulfate was prepared, with zinc ion concentrations of 150 g / L and magnesium ion concentrations of 15 g / L. Sodium fluoride solid was added to pure water and stirred thoroughly to obtain a fluoride precipitant slurry. The zinc-magnesium mixed solution was added to the fluoride precipitant slurry, wherein the molar ratio of fluoride ions in the precipitant to magnesium ions in the zinc-magnesium mixed solution was 4:1, and the volume ratio of the zinc-magnesium mixed solution to the fluoride precipitant slurry was 5:1. The mixture was then stirred in a water bath at 70°C and 500 rpm for 30 min to allow for complete precipitation. After the reaction, the solid and liquid were separated, the filtration rate was measured, and the magnesium precipitation rate was calculated. The result showed a filtration rate of 7.1 L / (m²). 2 (·h), the precipitation rate of magnesium is 86.35%.

[0019] Comparative Example 2: In Comparative Example 2, no sodium fluoride was added, and the mass of zinc fluoride was equal to the total mass of sodium fluoride and zinc fluoride in Example 1 (i.e., the mass of the fluorine-containing compound in Comparative Example 1 was equivalent to the total mass of the fluorine-containing compound in Example 1). Other experimental conditions were consistent with those in Example 1; the specific conditions and processes are as follows: A 50 mL mixed solution of zinc sulfate and magnesium sulfate was prepared, wherein the zinc ion concentration was 150 g / L and the magnesium ion concentration was 15 g / L. Solid zinc fluoride was added to pure water and stirred thoroughly to obtain a fluoride precipitant slurry. The zinc-magnesium mixed solution was added to the fluoride precipitant slurry, wherein the molar ratio of fluoride ions in the precipitant to magnesium ions in the zinc-magnesium mixed solution was 4:1, and the volume ratio of the zinc-magnesium mixed solution to the fluoride precipitant slurry was 5:1. Subsequently, the mixture was stirred in a water bath at 70 °C and 500 rpm for 30 min to allow for complete precipitation. After the reaction, the solid and liquid were separated, the filtration rate was measured, and the magnesium precipitation rate was calculated. The result showed that the filtration rate was 12.6 L / (m²). 2 (·h), the precipitation rate of magnesium is 58.27%.

[0020] Comparative Example 3: In Comparative Example 3, zinc fluoride was not added. The mass of sodium fluoride was equal to the total mass of sodium fluoride and zinc fluoride in Example 1 (i.e., the mass of the fluorine-containing compound in Comparative Example 1 was equivalent to the total mass of the fluorine-containing compound in Example 1). The fluoride was added via a positive addition method (i.e., the fluoride was added directly to the zinc-magnesium mixed solution). Other experimental conditions remained consistent with Example 1. The specific conditions and processes are as follows: A 50 mL mixed solution of zinc sulfate and magnesium sulfate was prepared, with zinc ion concentrations of 150 g / L and magnesium ion concentrations of 15 g / L. Sodium fluoride solid was added to pure water and stirred thoroughly to obtain a fluoride precipitant slurry. This fluoride precipitant slurry was then added to the zinc-magnesium mixed solution, where the molar ratio of fluoride ions in the precipitant to magnesium ions in the zinc-magnesium mixed solution was 4:1, and the volume ratio of the zinc-magnesium mixed solution to the fluoride precipitant slurry was 5:1. The mixture was then stirred in a water bath at 70°C and 500 rpm for 30 minutes to allow for complete precipitation. After the reaction, the solid and liquid were separated, the filtration rate was measured, and the magnesium precipitation rate was calculated. The result showed a filtration rate of 3.2 L / (m²). 2 (·h), the precipitation rate of magnesium is 75.04%.

[0021] Comparative Example 4: In Comparative Example 4, no sodium fluoride was added, and the mass of zinc fluoride was equal to the total mass of sodium fluoride and zinc fluoride in Example 1 (i.e., the mass of the fluorine-containing compound in Comparative Example 1 was equivalent to the total mass of the fluorine-containing compound in Example 1). Furthermore, the fluoride was added via a positive addition method (i.e., the fluoride was added directly to the zinc-magnesium mixed solution). All other experimental conditions remained consistent with those in Example 1. The specific conditions and processes are as follows: A 50 mL mixed solution of zinc sulfate and magnesium sulfate was prepared, with zinc ion concentrations of 150 g / L and magnesium ion concentrations of 15 g / L. Solid zinc fluoride was added to pure water and stirred thoroughly to obtain a fluoride precipitant slurry. This fluoride precipitant slurry was then added to the zinc-magnesium mixed solution, where the molar ratio of fluoride ions in the precipitant to magnesium ions in the zinc-magnesium mixed solution was 4:1, and the volume ratio of the zinc-magnesium mixed solution to the fluoride precipitant slurry was 5:1. The mixture was then stirred in a water bath at 70°C and 500 rpm for 30 minutes to allow for complete precipitation. After the reaction, the solid and liquid were separated, the filtration rate was measured, and the magnesium precipitation rate was calculated. The result showed a filtration rate of 3.4 L / (m²). 2 (·h), the precipitation rate of magnesium is 52.72%.

[0022] Comparative Example 5: The fluoride was added via a direct addition method (i.e., the fluoride was added forward into the zinc-magnesium mixed solution), and other experimental conditions remained consistent with those in Example 1; the specific conditions and process are as follows: A 50 mL mixed solution of zinc sulfate and magnesium sulfate was prepared, wherein the zinc ion concentration was 150 g / L and the magnesium ion concentration was 15 g / L. Sodium fluoride and zinc fluoride solids were added to pure water, with a molar ratio of sodium fluoride to zinc fluoride of 6:1. After thorough stirring, a fluoride precipitant slurry was obtained. The fluoride precipitant slurry was added to the zinc-magnesium mixed solution, wherein the molar ratio of fluoride ions in the precipitant to magnesium ions in the zinc-magnesium mixed solution was 4:1, and the volume ratio of the zinc-magnesium mixed solution to the fluoride precipitant slurry was 5:1. The mixture was then stirred in a water bath at 70 °C and 500 rpm for 30 min to allow for complete precipitation. After the reaction, the solid and liquid were separated, the filtration rate was measured, and the magnesium precipitation rate was calculated. The result showed a filtration rate of 10.7 L / (m²). 2 (·h), the precipitation rate of magnesium is 71.26%.

[0023] The statistical results of the experiments in Examples 1-4 and Comparative Examples 1-5 are shown in Table 1: Table 1. Filtration rates and magnesium removal rates of Examples 1-4 and Comparative Examples 1-5

[0024] The experimental data from Examples 1-4 and Comparative Examples 1-5 show that the present invention, by using a mixture of sodium fluoride and zinc fluoride as a precipitant and adding a zinc-magnesium mixed solution in reverse to the precipitant, can reduce the filtration rate from less than 4 L / (m²) 2 •h) increased to 80.4 L / (m 2 (h) (Example 1), the filtration speed is fast, significantly improving the filtration efficiency, while the magnesium precipitation rate is 92.63% (Example 1), demonstrating a significant magnesium removal effect; in contrast, when either sodium fluoride or zinc fluoride is used in the comparative example, the filtration speed decreases; when fluoride is added forward to the zinc-magnesium mixed solution, the filtration speed is greatly reduced, and the magnesium removal rate decreases; the present invention, by adding sodium fluoride and zinc fluoride precipitants in reverse to the zinc-magnesium mixed solution, allows magnesium ions to diffuse slowly in a fluoride-rich environment, and crystal nuclei to grow continuously in a smaller area, resulting in larger particle sizes. The process effectively removes magnesium ions from zinc leaching solutions by combining sodium fluoride and zinc fluoride with a reverse addition method. This balances the driving force of the precipitation reaction with the magnesium precipitation rate, overcoming the difficulties in filtration and insufficient magnesium precipitation caused by single precipitants and forward addition methods. The entire process operates under mild conditions, at atmospheric pressure and temperatures close to those of zinc leaching solutions in wet smelting, making it suitable for industrial application and possessing high application value.

[0025] Therefore, those skilled in the art will recognize that although embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A method for rapid and efficient removal of magnesium from wet zinc smelting leaching solutions, characterized in that, The method includes the following steps: Step S1: Add fluoride to pure water and stir thoroughly to obtain a fluoride precipitant slurry; Step S2: Add zinc-magnesium mixed solution to the fluoride precipitant slurry obtained in step S1, and carry out the precipitation reaction fully under stirring and heating conditions; Step S3: After step S2, solid-liquid separation is performed to obtain magnesium precipitate and zinc-containing filtrate.

2. The method for rapid and efficient removal of magnesium from wet zinc smelting leaching solution as described in claim 1, characterized in that, The fluoride is a mixture of sodium fluoride and zinc fluoride.

3. The method for rapid and efficient removal of magnesium from wet zinc smelting leaching solution as described in claim 2, characterized in that, The molar ratio of fluoride ions in the fluoride to magnesium ions in the zinc-magnesium mixed solution is 2:1-4:

1.

4. The method for rapid and efficient removal of magnesium from wet zinc smelting leaching solution as described in claim 3, characterized in that, The molar ratio of fluoride ions in the fluoride to magnesium ions in the zinc-magnesium mixed solution is 4:

1.

5. The method for rapid and efficient removal of magnesium from wet zinc smelting leaching solution as described in claim 2, characterized in that, In step S1, the molar ratio of sodium fluoride to zinc fluoride is 1:5-10:

1.

6. The method for rapid and efficient removal of magnesium from wet zinc smelting leaching solution as described in claim 5, characterized in that, In step S1, the molar ratio of sodium fluoride to zinc fluoride is 6:

1.

7. The method for rapid and efficient removal of magnesium from wet zinc smelting leaching solution as described in claim 1, characterized in that, In step S2, the volume ratio of the zinc-magnesium mixed solution to the fluoride precipitant slurry is 5:1-10:

1.

8. The method for rapid and efficient removal of magnesium from wet zinc smelting leaching solution as described in claim 1, characterized in that, In step S2, the zinc ion content in the zinc-magnesium mixed solution is 130-150 g / L, and the magnesium ion content is 10-15 g / L.

9. The method for rapid and efficient removal of magnesium from wet zinc smelting leaching solution as described in claim 1, characterized in that, In step S2, the reaction temperature is 60-80℃ and the reaction time is 15-60 min.

10. The method for rapid and efficient removal of magnesium from wet zinc smelting leaching solution as described in claim 9, characterized in that, In step S2, the reaction temperature is 70°C and the reaction time is 30 min.

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