Method for intensively removing iron and arsenic in zinc sulfate solution by ultrasonic synergistic functional composite neutralizer

Abstract

The invention relates to a method for intensively removing iron and arsenic in a zinc sulfate solution through an ultrasonic synergistic functional composite neutralizer, and belongs to the technical field of hydrometallurgy solution purification. The method comprises the following steps: heating a zinc sulfate solution containing ferrous ions and arsenic ions to 60-95 DEG C, adding an oxidizing agent, uniformly mixing, then introducing ultrasonic waves, adding a rapid kinetic regulator, carrying out ultrasonic-enhanced initial oxidation reaction for 5-10 minutes, and rapidly adjusting the pH value of the solution to 2.8-3.5 to obtain a mixed solution; at the temperature of 60-95 DEG C, slowly adding an accurate precipitation accelerant and a buffer stabilizer into the mixed solution, uniformly mixing, carrying out ultrasonic-enhanced continuous oxidation reaction for 15-20 minutes, stably raising the pH value of the solution to 3.8-4.5, continuing to react for 10-30 minutes, and carrying out solid-liquid separation to obtain precipitation slag and a solution subjected to iron and arsenic precipitation. The rapid dynamic regulator is responsible for rapidly starting the reaction and creating initial conditions for goethite nucleation; the accurate precipitation accelerant ensures pH stability and deep co-precipitation of impurities in the middle and later periods of the reaction; the buffer stabilizer effectively eliminates local over-alkali and maintains the system stability.

Description

Technical Field

[0001] This invention relates to a method for removing iron and arsenic from zinc sulfate solution using an ultrasonic synergistic functional composite neutralizing agent, belonging to the field of hydrometallurgical solution purification technology. Background Technology

[0002] In the hydrometallurgical process of zinc, iron and arsenic elements contained in the concentrate are transferred to the zinc sulfate solution system after leaching with sulfuric acid, and the iron ion concentration is usually higher than 1 g / L. Iron (as Fe) 2+ and Fe 3+ The presence of Fe (in its various forms) and arsenic negatively impacts the overall process flow, final product quality, and economic benefits, specifically in the following ways: First, it increases energy consumption, leading to decreased current efficiency. During electrolysis, Fe... 3+ Compared to Zn 2+ Arsenic readily undergoes reduction reactions at the cathode, preferentially consuming current and thus inhibiting zinc electrodeposition. Arsenic, on the other hand, readily adsorbs onto the cathode surface or undergoes reduction, significantly lowering the hydrogen evolution overpotential. This causes some current to be used for hydrogen evolution reactions rather than zinc deposition, resulting in a significant decrease in current efficiency. Secondly, it damages the quality of cathode zinc: Iron may precipitate on the cathode surface, and hydrolysis products (such as Fe(OH)3 colloids) are encapsulated within the zinc deposition layer, causing excessive iron content in the cathode zinc and reducing the purity grade of the finished zinc product. Arsenic and its compounds may also be trapped or adsorbed within the zinc layer, leading to quality defects in the cathode zinc plate such as blackening, loose structure, porosity, easy scorching, and breakage. Therefore, effectively removing iron and arsenic impurities from the zinc sulfate solution is a crucial step in improving the purity and economic efficiency of zinc products.

[0003] Traditional iron removal technologies mainly include the jaundice process, the hematite process, and the goethite process. Among them, the goethite process is one of the mainstream methods for iron removal in hydrometallurgy, especially widely used in zinc, nickel, and cobalt smelting. Its core principle is to remove Fe from the solution under strictly controlled conditions (temperature, pH, and redox potential). 3+Hydrolysis and crystallization form goethite (α-FeOOH) precipitate with good adsorption properties, thereby achieving deep iron removal. Currently, the removal of arsenic from goethite in traditional iron removal processes mainly relies on the adsorption and co-precipitation of As(V), the effectiveness of which is affected by the arsenic valence state, reaction conditions, the molar ratio of arsenic to iron, and impurity ions. Patent application CN105753218A discloses a method for removing trivalent arsenic, which fully oxidizes highly toxic trivalent arsenic (As(III)) to more easily precipitated pentavalent arsenic (As(V)) by precisely controlling the redox potential, and forms a stable precipitate with iron. Patent application CN120060641A discloses a method for deep removal of arsenic from high-arsenic zinc sulfate solution, which optimizes the formation conditions of goethite and improves co-precipitation efficiency by adding neutralizing agents (such as zinc roasted sand) and oxidants in stages or gradients and strictly controlling the pH value and Fe / As molar ratio of the reaction process. Patent application CN106834752A discloses a method for seed-induced enhanced removal of trivalent arsenic from wastewater. Based on the traditional goethite method, it introduces seed crystals or other flocculants to improve the physical properties of the goethite precipitate (such as particle size and strength), thereby significantly increasing sedimentation and filtration speed, achieving "deep" iron removal and incidental arsenic removal. Patent application CN106834752A also discloses a method for treating acidic high-arsenic wastewater. For high-arsenic raw materials, it uses an enhanced pre-oxidation step and introduces auxiliary precipitants (such as copper and calcium ions) to generate more insoluble arsenates. These patent applications require precise control of the iron-arsenic ratio (Fe / As) and redox potential, and the addition of flocculants introduces new impurity ions. Although the goethite method can synergistically remove some arsenic, actual production still faces the problem of low As(III) oxidation efficiency. The removal of arsenite (As(III)) is generally more difficult than that of arsenate (As(V)) because arsenite has a weaker affinity for goethite surfaces and is less likely to form coprecipitates. Arsenic adsorption or coprecipitation may take a long time to reach equilibrium. Insufficient mixing can lead to inadequate contact between arsenic and goethite, thus reducing the removal rate. Therefore, a new method is urgently needed to overcome the bottlenecks in the simultaneous removal of iron and arsenic using the goethite method. Summary of the Invention

[0004] To address the technical challenges of removing iron and arsenic impurities from zinc sulfate solutions, this invention proposes a method for enhancing the removal of iron and arsenic from zinc sulfate solutions using an ultrasonic synergistic functional composite neutralizing agent. This method employs a composite system composed of three complementary neutralizing agents: an ultrasonic synergistic rapid kinetic regulator, a precise precipitation promoter, and a buffer stabilizer. Through the temporal synergy and synergistic effect of these agents in terms of dissolution rate, reactivity, and chemical function, precise stepwise control of the pH of the zinc sulfate solution and optimization of the precipitation process are achieved. The rapid kinetic regulator is responsible for the rapid initiation of the reaction, creating initial conditions for goethite nucleation; the precise precipitation promoter ensures pH stability and deep co-precipitation of impurities in the later stages of the reaction; and the buffer stabilizer effectively eliminates localized over-alkalinity, maintaining system stability. The functional coupling of the three neutralizing agents produces a synergistic effect of "initiation-deepening-stabilization." This method simultaneously achieves highly efficient removal of iron and arsenic, with removal rates reaching 99.9% and 99.74%, respectively.

[0005] A method for enhancing the removal of iron and arsenic from zinc sulfate solution using an ultrasound-synergistic functional compound neutralizer, comprising the following specific steps: (1) Heat the zinc sulfate solution containing ferrous ions and arsenic ions to 60~95℃, add oxidant and mix evenly, then introduce ultrasound, add rapid kinetic regulator to perform ultrasound-enhanced initial oxidation reaction for 5~10 min and rapidly adjust the pH of the solution to 2.8~3.5 to obtain a mixed solution; (2) Under ultrasound and at a temperature of 60~95℃, a precise precipitation promoter and a buffer stabilizer are slowly added to the mixed solution and mixed evenly. The continuous oxidation reaction is enhanced by ultrasound for 15~20 min and the pH value of the solution is steadily increased to 3.8~4.5. The reaction is continued for 10~30 min, and the solid and liquid are separated to obtain the precipitated residue and the liquid after iron and arsenic precipitation.

[0006] Preferably, the zinc sulfate solution containing ferrous ions and arsenic ions in step (1) contains 120~150g / L zinc, 0.2~1g / L arsenic, 8~15g / L iron, 5~50mg / L antimony, and 1~20mg / L germanium.

[0007] Preferably, the oxidant in step (1) is H2O2, chlorine, sodium chlorate, potassium permanganate or sodium persulfate, and the amount of oxidant added is 1.2 to 1.5 times the theoretical amount.

[0008] Preferably, the rapid kinetic regulator in step (1) is sodium hydroxide, calcium oxide, calcium hydroxide, potassium hydroxide, or sodium carbonate.

[0009] More preferably, the ultrasonic power in the initial oxidation reaction stage is 120~160W and the frequency is 15~20 kHz.

[0010] Preferably, in step (2), the precise precipitation promoter is zinc oxide, zinc carbonate, zinc hydroxide, basic copper carbonate or calcium carbonate, and the buffer stabilizer is magnesium carbonate, magnesium hydroxide or dolomite; the molar ratio of the precise precipitation promoter to the buffer stabilizer is 10:2 to 10:8.

[0011] Preferably, the ultrasonic power of the continuous oxidation reaction is 40~80W and the frequency is 5~15kHz.

[0012] The principle of this invention, which utilizes an ultrasonic synergistic functional compound neutralizer to enhance the removal of iron and arsenic from zinc sulfate solution, is as follows: (1) Ultrasonic synergy with a "rapid kinetic regulator" enables instantaneous, uniform, rapid start-up and homogeneous nucleation. The extreme instantaneous high temperature and pressure and intense microjets generated by ultrasonic cavitation greatly accelerate the dissolution and mass transfer process of the neutralizer particles, completely eliminating the localized over-alkali zone caused by uneven mixing under traditional stirring. This provides Fe 3+ Hydrolysis creates an optimal thermodynamic environment, which promotes the rapid, large-scale, and uniform generation of goethite nuclei in the solution (homogeneous nucleation), solving the problems of slow reaction start-up and insufficient number of nuclei in traditional processes; Fast kinetic modifiers provide extremely high initial reaction rates, utilizing their rapid dissolution properties to consume large amounts of H₂ in a short time. + This rapidly raises the solution pH from strongly acidic to the critical region (approximately pH 2.8-3.2) where goethite (α-FeOOH) begins spontaneous nucleation, providing a strong initial impetus for the entire precipitation process. This avoids initial lag and ensures the abundant and rapid formation of goethite nuclei. The rapid kinetic regulator provides sufficient crystallization nuclei for subsequent precipitation stages, laying the foundation for efficient iron removal. The reaction formula is: CaO + 2H + → Ca 2+ + H2O (1) Fe 3+ + 3H₂O → FeOOH↓ + 3H + (2) (2) Ultrasonic synergy with "precision precipitation promoter" promotes directional crystallization and deep co-precipitation of impurities. The powerful shear force and micro-jets generated by ultrasonic cavitation can continuously scour the surface of neutralizer particles, preventing them from being encapsulated and passivated by hydrolysis products, thus ensuring the stability and controllability of their dissolution rate. At the same time, this intense physical force can effectively prevent the agglomeration of newly formed goethite microcrystals and provide energy for their crystal growth, inducing them to grow directionally into crystals with complete crystals, large size, and large specific surface area. The increased specific surface area and the fresh crystal surface cleaned by ultrasound provide more active sites for the adsorption and co-precipitation of arsenates. In addition, the free radicals such as ·OH generated by ultrasonic cavitation can also synergistically oxidize As(III) to As(V), further improving the arsenic removal efficiency. The core function of the precision precipitation promoter is "precise control" and "deep purification". Its slow dissolution characteristics allow for fine adjustment of the system pH, achieving a smooth transition to the final pH (3.8-4.5), avoiding the back dissolution of precipitates or crystal destruction caused by a sudden increase in pH. More importantly, the specific metal cations (such as Zn) introduced during its dissolution 2+ Cu 2+ (etc.) can react with AsO4 3- GeO3 2- When anions form sparingly soluble salts (e.g., M3(AsO4)2 or M2GeO4, where M represents a divalent metal ion), deep removal of impurity ions such as arsenic and germanium is achieved through a co-precipitation effect. Precision precipitation promoters build upon the rapid start created by fast kinetic modifiers, achieving deep removal of impurities and precise control of the final reaction conditions; the reaction formula is: ZnO + 2H + →Zn 2+ + H2O (3) 3Zn 2+ +2AsO4 3- →Zn3(AsO4)2↓(4) 2Zn 2+ +GeO3 2- →Zn2GeO4↓(5) Ultrasound, acting as a synergistic "buffer stabilizer," maintains the dynamic stability of the macroscopic and microscopic reaction system. The powerful macroscopic stirring and microscopic mixing effect of ultrasound allows the buffer stabilizer to distribute uniformly throughout the reaction system at a near "molecular level." This enables it to neutralize Fe instantly and efficiently. 3+ Hydrolysis instantaneously generates H in the microscopic region +This process eliminates microscopic pH fluctuations that may be caused by the addition of a neutralizing agent, thus maintaining an extremely stable pH environment throughout the entire reaction space and time. This environment maximally inhibits the formation of amorphous Fe(OH)3 colloids, forcing all iron ions to follow the crystallization pathway. Simultaneously, the stable environment also creates optimal conditions for the precipitation of sparingly soluble salts. The core function of the neutralizing agent is to maintain the "stability" of the reaction system. Its mild hydrolytic properties allow it to promptly consume Fe... 3+ H generated instantaneously during hydrolysis + Or neutralize localized high OH levels that may result from uneven mixing. - This effectively suppresses the formation of amorphous Fe(OH)3 colloids, promotes the complete conversion of iron to well-crystallized goethite, and creates a stable and uniform thermodynamic environment for the co-precipitation of impurities. The buffer stabilizer ensures that the functions of the first two types of neutralizing agents are fully utilized and directly optimizes the physical properties of the precipitate. The reaction formula is: MgCO3+ 2H + → Mg 2+ +CO2↑+ H2O(6) The three types of neutralizing agents are functionally sequential and complementary in effect, forming a complete "start-deepen-stabilize" reaction chain. Their synergistic effect is the key to obtaining excellent purification results and superior slag performance.

[0013] The beneficial effects of this invention are: (1) This invention is the first to combine ultrasound with three types of functional neutralizers (rapid kinetic modifier, precise precipitation promoter, and buffer stabilizer), solving the industry problem that a single functional neutralizer cannot simultaneously achieve reaction rate, precipitation depth, and process stability; the high-energy microjets released during the collapse of ultrasonic cavitation bubbles and the local high-temperature and high-pressure environment significantly reduce Fe 3+ The activation energy of hydrolysis promotes Fe 3+ It rapidly forms goethite crystal nuclei and increases surface vacancies, achieving the purpose of deep removal of iron and arsenic; (2) In the method of the present invention, under the synergistic effect of ultrasonic cavitation and high temperature, Fe 3+ The hydrolysis nucleation rate is accelerated, the number of vacancies in goethite increases, and its adsorption capacity is improved; the final removal rates of iron and arsenic can reach 99.99% and 99.74%, respectively, which are 6.85% and 8.03% higher than those of the traditional goethite method, meeting the requirements of deep purification of solution in hydrometallurgical zinc refining (Fe<20 mg / L, As<1 mg / L). (3) In the method of the present invention, ultrasound inhibits the excessive growth and agglomeration of goethite crystals, generating precipitate slag with uniform particle size, large specific surface area and many surface vacancies, thereby reducing the cost of subsequent processing. (4) The goethite precipitate slag of the present invention can realize the resource utilization of waste and is suitable for industrial-grade iron precipitation process. Attached Figure Description

[0014] Figure 1 SEM image of the precipitate residue from Example 1; Figure 2 SEM image of the precipitate residue in Comparative Example 1; Figure 3 SEM image of the precipitate residue in Comparative Example 2; Figure 4 XRD patterns of the precipitate residues from Example 1 and Comparative Example 1; Figure 5 Here is a SEM image of the precipitate residue from Example 2; Figure 6 Here is a SEM image of the precipitate residue from Example 3; Figure 7 This is a SEM image of the precipitate residue from Example 4. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0016] Example 1: The content of each metal element in the zinc sulfate solution containing ferrous ions and arsenic ions in this example is shown in Table 1. Table 1 Contains Fe 2+ The content of various metal elements in zinc sulfate solution

[0017] A method for enhancing the removal of iron and arsenic from zinc sulfate solution using an ultrasound-synergistic functional compound neutralizer, comprising the following specific steps: (1) Heat the zinc sulfate solution containing ferrous ions and arsenic ions to 85°C, add oxidant (Na2S2O8) and mix evenly, then introduce ultrasound, add rapid kinetic regulator (calcium hydroxide) to perform ultrasound-enhanced initial oxidation reaction for 5 min and quickly adjust the pH of the solution to 3.0 to obtain a mixed solution; the amount of oxidant (Na2S2O8) added is 1.3 of the theoretical amount, the ultrasound power in the initial oxidation reaction stage is 160W and the frequency is 20 kHz; (2) Under ultrasound and at a temperature of 85°C, a precise precipitation promoter (zinc hydroxide) and a buffer stabilizer (magnesium hydroxide) were slowly added to the mixed solution and mixed evenly. The continuous oxidation reaction was enhanced by ultrasound for 20 min and the pH value of the solution was steadily increased to 4.0. The reaction was continued for 30 min, and the solid and liquid were separated to obtain the precipitated residue and the liquid after iron and arsenic precipitation. The molar ratio of the precise precipitation promoter to the buffer stabilizer was 10:6. The ultrasound power of the continuous oxidation reaction was 80W and the frequency was 15 kHz. In this embodiment, the Fe content in the solution after iron and arsenic precipitation was 9.86 mg / L, and the As content was 1.02 mg / L. The removal rate of impurities in the zinc solution reached 99.90%, and the removal rate of arsenic reached 99.49%. The precipitate consisted of monodisperse needle-like α-FeOOH crystals and As, with a large number of vacancies generated on the surface. This was due to the cavitation collapse instantaneous high pressure promoting Fe... 3+ Rapid nucleation occurs, and the shear force generated by cavitation bubble oscillation creates vacancies, thereby enhancing the adsorption capacity for arsenic.

[0018] Comparative Example 1: Containing Fe 2+ The zinc sulfate solution contained the same metal element composition as in Example 1. The zinc sulfate solution containing ferrous ions and arsenic ions was heated to 85°C, an oxidant (Na2S2O8) was added and mixed evenly, and then ultrasound was introduced. A precise precipitation promoter (zinc hydroxide) was added to adjust the pH of the solution to 4.0. The oxidation reaction was carried out for 30 min, and the solid and liquid were separated to obtain a precipitate residue and a liquid after precipitating ferrous ions and arsenic ions. The ultrasound power was 80W and the frequency was 15 kHz. In this comparative example, the Fe content in the solution after iron and arsenic precipitation was 513 mg / L, the As content was 14.94 mg / L, and the Zn content was 127032 mg / L. The removal rate of iron impurities in the zinc solution was 94.87%, and the removal rate of arsenic was 92.53%. The XRD patterns of the precipitates obtained by the conventional iron and arsenic removal methods in Example 1 and this comparative example are shown in the figure. Figure 4 ,from Figure 4 It can be seen that under normal conditions, the intensity of the characteristic peaks of goethite is low, indicating that the crystallinity of hematite is limited. Simultaneously, amorphous Fe(OH)3 was detected. Under ultrasonic conditions, the crystalline morphology of goethite slag is obvious, the diffraction peaks of Fe(OH)3 disappear, and the characteristic peaks of ZnSO4 weaken. This is attributed to the ultrasonic waves disrupting the colloidal encapsulation layer, thereby exposing new reaction surfaces and promoting the structural transformation of Fe(OH)3. In summary, X-ray diffraction analysis confirms that ultrasonic waves promote the structural transformation of Fe... 3+ The preferential formation of chlorite, rather than the disordered aggregation to form Fe(OH)3, is beneficial to improving the adsorption effect of chlorite on arsenic, thereby increasing the removal rate of iron and arsenic.

[0019] Comparative Example 2: The difference between this comparative example and Comparative Example 1 is that ultrasound is not introduced; In this comparative example, the Fe content in the solution after iron and arsenic precipitation was 686 mg / L, the As content was 16.58 mg / L, and the Zn content was 126076 mg / L. The removal rate of iron impurities in the zinc solution was 93.14%, and the removal rate of arsenic was 91.71%. SEM image of the precipitate residue in Example 1 is shown below. Figure 1 SEM images of the precipitate obtained by the conventional iron and arsenic removal method in Comparative Example 1 are shown below. Figure 2The SEM image of the precipitate obtained in this comparative example is shown in [image missing]. Figure 3 ,from Figures 1-3 It is known that goethite under normal conditions mainly consists of micron-sized spherical and massive aggregates with a dense surface and small pores, resulting in poor solution permeability. Goethite slag under ultrasonic conditions has a defective and porous surface with fractured needle-like structures, exhibiting better dispersibility. This is because the ultrasonic waves acting on the surface of the goethite slag disrupt the Zn on the FeOOH surface. 2+ Electrostatic adsorption leads to the precipitation of more arsenic.

[0020] Example 2: The zinc sulfate solution containing ferrous ions and arsenic ions in this example is the same as in Example 1; A method for enhancing the removal of iron and arsenic from zinc sulfate solution using an ultrasound-synergistic functional compound neutralizer, comprising the following specific steps: (1) Heat the zinc sulfate solution containing ferrous ions and arsenic ions to 70°C, add oxidant (chlorine) and mix well, then introduce ultrasound, add rapid kinetic regulator (sodium carbonate) to perform ultrasound-enhanced initial oxidation reaction for 8 min and quickly adjust the pH of the solution to 3.5 to obtain a mixed solution; the amount of oxidant (chlorine) added is 1.2 times the theoretical amount, the ultrasound power in the initial oxidation reaction stage is 120W and the frequency is 15kHz; (2) Under ultrasound and at a temperature of 75°C, a precise precipitation promoter (zinc carbonate) and a buffer stabilizer (magnesium carbonate) were slowly added to the mixed solution and mixed evenly. The continuous oxidation reaction was enhanced by ultrasound for 15 min and the pH value of the solution was steadily increased to 3.8. The reaction was continued for 25 min, and the solid and liquid were separated to obtain the precipitated residue and the liquid after iron and arsenic precipitation. The molar ratio of the precise precipitation promoter to the buffer stabilizer was 10:4. The ultrasound power of the continuous oxidation reaction was 60W and the frequency was 10 kHz. The SEM image of the precipitate in this embodiment is shown below. Figure 5 In this embodiment, the Fe content in the solution after precipitating iron and arsenic was 185.42 mg / L, and the As content was 5.2 mg / L. The removal rate of impurities in the zinc solution reached 98.15%, and the removal rate of arsenic reached 97.40%. The precipitate was composed of monodisperse needle-like α-FeOOH crystals and As, and a large number of vacancies were generated on the surface. This is due to the instantaneous high pressure of cavitation collapse promoting Fe... 3+ Rapid nucleation occurs, and the shear force generated by cavitation bubble oscillation creates vacancies, thereby enhancing the adsorption capacity for arsenic.

[0021] Example 3: The zinc sulfate solution containing ferrous ions and arsenic ions in this example is the same as in Example 1; A method for enhancing the removal of iron and arsenic from zinc sulfate solution using an ultrasound-synergistic functional compound neutralizer, comprising the following specific steps: (1) Heat the zinc sulfate solution containing ferrous ions and arsenic ions to 95°C, add oxidant (H2O2) and mix well, then introduce ultrasound, add rapid kinetic regulator (sodium hydroxide) to perform ultrasound-enhanced initial oxidation reaction for 10 min and quickly adjust the pH of the solution to 3.3 to obtain a mixed solution; the amount of oxidant (H2O2) added is 1.5 times the theoretical amount, the ultrasound power in the initial oxidation reaction stage is 140W and the frequency is 20 kHz; (2) Under ultrasound and at a temperature of 95°C, a precise precipitation promoter (zinc oxide) and a buffer stabilizer (magnesium hydroxide) were slowly added to the mixed solution and mixed evenly. The continuous oxidation reaction was enhanced by ultrasound for 18 min and the pH value of the solution was steadily increased to 4.5. The reaction was continued for 28 min, and the solid and liquid were separated to obtain the precipitated residue and the liquid after iron and arsenic precipitation. The molar ratio of the precise precipitation promoter to the buffer stabilizer was 10:6. The ultrasound power of the continuous oxidation reaction was 40W and the frequency was 15kHz. The SEM image of the precipitate in this embodiment is shown below. Figure 6 In this embodiment, the Fe content in the solution after iron and arsenic precipitation was 1.3 mg / L, and the As content was 0.52 mg / L. The removal rate of impurities in the zinc solution reached 99.99%, and the removal rate of arsenic reached 99.74%. The precipitate consisted of monodisperse needle-like α-FeOOH crystals and As, with a large number of vacancies generated on the surface. This was due to the instantaneous high pressure during cavitation collapse promoting Fe... 3+ Rapid nucleation occurs, and the shear force generated by cavitation bubble oscillation creates vacancies, thereby enhancing the adsorption capacity for arsenic.

[0022] Example 4: The zinc sulfate solution containing ferrous ions and arsenic ions in this example is the same as in Example 1; A method for enhancing the removal of iron and arsenic from zinc sulfate solution using an ultrasound-synergistic functional compound neutralizer, comprising the following specific steps: (1) Heat the zinc sulfate solution containing ferrous ions and arsenic ions to 60°C, add the oxidant (potassium permanganate) and mix well, then introduce ultrasound, add a rapid kinetic regulator (potassium hydroxide) to perform ultrasound-enhanced initial oxidation reaction for 6 min and quickly adjust the pH of the solution to 2.8 to obtain a mixed solution; the amount of oxidant (potassium permanganate) added is 1.4 times the theoretical amount, the ultrasound power in the initial oxidation reaction stage is 120W and the frequency is 15kHz; (2) Under ultrasound and at a temperature of 60°C, a precise precipitation promoter (calcium carbonate) and a buffer stabilizer (dolomite) were slowly added to the mixed solution and mixed evenly. The continuous oxidation reaction was enhanced by ultrasound for 16 min and the pH value of the solution was steadily increased to 4.2. The reaction was continued for 15 min, and the solid and liquid were separated to obtain the precipitated residue and the liquid after iron and arsenic precipitation. The molar ratio of the precise precipitation promoter to the buffer stabilizer was 10:4. The ultrasound power of the continuous oxidation reaction was 60W and the frequency was 10kHz. The SEM image of the precipitate in this embodiment is shown below. Figure 7 In this embodiment, the Fe content in the solution after iron and arsenic precipitation was 480 mg / L, and the As content was 13 mg / L. The removal rate of impurities in the zinc solution reached 95.20%, and the removal rate of arsenic reached 93.50%. The precipitate consisted of monodisperse needle-like α-FeOOH crystals and As, with a large number of vacancies generated on the surface. This was due to the cavitation collapse instantaneous high pressure promoting Fe... 3+ Rapid nucleation occurs, and the shear force generated by cavitation bubble oscillation creates vacancies, thereby enhancing the adsorption capacity for arsenic.

[0023] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A process for the removal of iron and arsenic from zinc sulphate solution by synergistic functional composite neutralizer enhanced ultrasonics characterised in that, The specific steps are as follows: (1) heating the zinc sulfate solution containing divalent iron ions and arsenic ions to 60-95℃, adding an oxidizing agent and mixing uniformly, then introducing ultrasonic, adding a fast kinetics regulator to ultrasonically strengthen the initial oxidation reaction for 5-10 min and rapidly adjust the solution pH to 2.8-3.5 to obtain a mixed solution; (2) under ultrasonic and temperature 60-95℃, slowly adding a precise precipitation accelerator and a buffer stabilizer to the mixed solution and mixing uniformly, ultrasonically strengthening the continuous oxidation reaction for 15-20 min and smoothly raising the solution pH to 3.8-4.5, continuing the reaction for 10-30 min, solid-liquid separation, obtaining a precipitate residue and a post-iron-arsenic liquid.

2. The method of claim 1, wherein the method is for removing iron and arsenic from a zinc sulfate solution using an ultrasound synergistic functional complexing agent. The zinc sulfate solution containing divalent iron ions and arsenic ions in step (1) contains zinc 120-150 g / L, arsenic 0.2-1 g / L, iron 8-15 g / L, antimony 5-50 mg / L, and germanium 1-20 mg / L.

3. The method of claim 1, wherein the method is for removing iron and arsenic from a zinc sulfate solution. The oxidizing agent in step (1) is H2O2, chlorine, sodium chlorate, potassium permanganate, or sodium persulfate, and the addition amount of the oxidizing agent is 1.2-1.5 times the theoretical amount.

4. The process for removal of iron and arsenic from zinc sulfate solution by synergistic functional composite neutralizer according to claim 1, characterized in that: The fast kinetics regulator in step (1) is sodium hydroxide, calcium oxide, calcium hydroxide, potassium hydroxide, or sodium carbonate.

5. The method of claim 1, wherein the method is for removing iron and arsenic from a zinc sulfate solution. The ultrasonic power in the initial oxidation reaction stage is 120-160 W, and the frequency is 15-20 kHz.

6. The method of claim 1, wherein the method is for removing iron and arsenic from a zinc sulfate solution. The precise precipitation accelerator in step (2) is zinc oxide, zinc carbonate, zinc hydroxide, basic copper carbonate, or calcium carbonate, and the buffer stabilizer is magnesium carbonate, magnesium hydroxide, or dolomite; the molar ratio of the precise precipitation accelerator to the buffer stabilizer is 10:2-10:

8.

7. The method of claim 6, wherein the method is for removing iron and arsenic from a zinc sulfate solution. The ultrasonic power in the continuous oxidation reaction is 40-80 W, and the frequency is 5-15 kHz.

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