A high molecular flocculant and a preparation method thereof

Abstract

This invention belongs to the field of manganese dioxide recovery, and particularly relates to a polymeric flocculant and its preparation method. The method includes: (1) mixing an inorganic polymeric coagulant, a linear polymeric polymer, and silica in a certain proportion to form a mixture, dissolving it in water, and adding an initiator to carry out a low-temperature thermal reaction to prepare a precursor; (2) mixing a crosslinking agent, ethanol, nitric acid, and polymeric aluminum iron silicate in a certain proportion, drying and grinding to prepare a prepolymer; (3) mixing the precursor and the prepolymer in a certain proportion, ultrasonically emulsifying to prepare a polymeric flocculant. This invention has a good flocculation and adsorption effect, and can effectively remove impurities in electrolyte raw materials, especially metal ion impurities, while avoiding the loss of manganese ions during the removal of metal ion impurities.

Description

Technical Field

[0001] This invention belongs to the field of manganese dioxide recovery, and particularly relates to a polymeric flocculant and its preparation method. Background Technology

[0002] The rapid development of electrolytic manganese dioxide in the battery industry is due to the high purity, good crystal form (γ-type), high chemical activity and electrochemical activity of the γ-MnO2 produced during the electrolysis process. It is currently the main raw material for high-performance chemical batteries. The quality of electrolytic manganese dioxide is crucial to battery performance, as it directly affects the battery's discharge and storage performance.

[0003] Traditional methods for electrolyzing manganese dioxide often lack effective impurity removal and process intensification techniques, resulting in high iron content and heavy metal impurities in the product, which negatively impacts product quality and significantly reduces its discharge performance. Therefore, the preparation of high-purity, high-performance electrolytic manganese dioxide has become a major research direction. Treating the electrolyte raw materials is the most direct and effective method, involving the selection of suitable flocculants to remove other metallic impurities from the electrolyte solution.

[0004] In existing technologies, inorganic flocculants or synthetic organic flocculants produce certain byproducts, resulting in poor flocculation effects, environmental pollution, and poor biodegradability of the sludge generated from water treatment. Although natural organic flocculants are readily biodegradable and do not cause secondary pollution during operation, their poor water solubility and susceptibility to biodegradation lead to decreased flocculation performance. Therefore, to purify the electrolyte solution by adding flocculants, artificially synthesized flocculants are necessary. Summary of the Invention

[0005] The present invention addresses the technical challenges of complex processes, severe pollution, and difficulty in effectively removing metal ion impurities in traditional electrolytic manganese dioxide production by providing a polymeric flocculant and its preparation method.

[0006] The main objective of this invention is:

[0007] First, it can change the flocculation and impurity removal mechanism of flocculants, thereby improving the flocculation and impurity removal effect;

[0008] Second, it can effectively remove impurities from specific metal ions.

[0009] Third, it has an extremely low impurity removal concentration threshold.

[0010] To achieve the above objectives, the present invention adopts the following technical solution.

[0011] A method for preparing a polymeric flocculant, the method comprising:

[0012] (1) Inorganic polymer coagulant, linear polymer and silica are mixed evenly in proportion to form a mixture, dissolved in water, and an initiator is added to carry out a low-temperature thermal reaction to prepare a precursor;

[0013] (2) Mix the crosslinking agent, ethanol, nitric acid and polymerized aluminum iron silicate in a certain proportion, dry and grind to prepare a prepolymer;

[0014] (3) Mix the precursor and prepolymer in proportion and emulsify by ultrasonication to prepare a polymeric flocculant.

[0015] As a preferred option

[0016] The inorganic polymeric flocculant mentioned in step (1) is polyaluminum chloride;

[0017] The linear polymer mentioned in step (1) is polyacrylamide.

[0018] As a preferred option

[0019] The inorganic polymer flocculant, linear polymer and silica mentioned in step (1) are mixed in a mass ratio of 1:(7.8-8.2):(4.8-5.2).

[0020] As a preferred option

[0021] The initiator in step (1) is potassium persulfate;

[0022] The amount of potassium persulfate used is 0.9 to 1.1 wt% of the mixture.

[0023] As a preferred option

[0024] The low-temperature thermal reaction in step (1) is carried out in a protective atmosphere, with the reaction temperature controlled at 45-55℃ and the reaction time at 120-180 min.

[0025] As a preferred option

[0026] The crosslinking agent in step (2) is tetrabutyl titanate;

[0027] The nitric acid concentration in step (2) is a 62-68 wt% nitric acid aqueous solution.

[0028] As a preferred option

[0029] In step (2), the crosslinking agent, ethanol, nitric acid, and polyaluminum ferric silicate are mixed in a mass ratio of 1:(1.8-2.2):(0.9-1.1):(0.1-0.3).

[0030] The drying and grinding process in step (2) involves drying at 120-130°C for 180-240 minutes, followed by grinding and crushing to obtain a 100-200 mesh prepolymer.

[0031] As a preferred option

[0032] The precursor and prepolymer in step (3) are mixed in a mass ratio of 1:(0.1 to 0.3).

[0033] As a preferred option

[0034] The ultrasonic emulsification in step (3) is performed at 45-50°C for 60-120 minutes.

[0035] A polymeric flocculant.

[0036] Excessive use of inorganic flocculants or synthetic organic flocculants may produce certain toxic side effects and pollute the environment. Furthermore, sludge generated during water treatment is not easily biodegradable. In contrast, most natural organic flocculants are extracted from animals or plants, possessing excellent flocculation effects and good biodegradability, without producing secondary pollution; therefore, they are considered environmentally friendly polymeric flocculants. However, natural organic flocculants have relatively small molecular weights, low charge densities, poor water solubility, and are easily biodegradable, leading to poor flocculation effects. To address this issue, the present invention synthesizes a novel organic-inorganic hybrid polymeric flocculant by hybridizing natural organic flocculants with inorganic flocculants. This flocculant is particularly efficient and performs superiorly in purifying metal ion impurities in the electrolytic raw solution during the electrolytic manganese dioxide process.

[0037] This invention uses a polyacrylamide composite as a substrate. After organic-inorganic modification, a polymeric flocculant with a distinct three-dimensional network structure is constructed. The three-dimensional porous material constructed in this invention has extremely high specific surface area and porosity, resulting in a larger contact area with metal ion impurities in the water system and exhibiting stronger bridging capabilities. In this invention, during ultrasonic emulsification, the inorganic and organic components of the precursor and prepolymer generate a new substance with a network structure. The organic monomer and the ultrasonically decomposed ionic free radicals initiate polymerization. Potentially charged points on the organic chains are ionicly bonded to the positively charged inorganic components, synthesizing a structure where the silicate segments of the polyacrylamide chain are ionicly bonded to the hydroxyl complexes in polyaluminum chloride. Simultaneously, the crystallization of silica on the network stabilizes the structure and improves the thermal stability of the flocculant. In subsequent performance testing, the polymeric flocculant neutralizes the charge of the wastewater system and adsorbs and bridging impurities for sedimentation.

[0038] In this invention, the polymeric flocculant is composed of an inorganic phase and an organic phase. Two bonding methods exist at the phase interface: ionic bonding and covalent bonding. Since ionic bonds are stronger than hydrogen bonds, breaking the ionic bond structure requires higher temperatures and energy, resulting in greater thermal stability, a wider effective operating range, and less stringent pH requirements for the treated water. However, in hybrid flocculants linked by ionic bonds, at excessively low concentrations, some inorganic and organic components ionize, causing changes in the structure of the polymeric flocculant and reducing flocculation stability. To ensure the stability of the hybrid product system, this invention adds tetrabutyl titanate, which covalently connects the inorganic and organic phases. This results in a polymeric flocculant with polyaluminum chloride as the core, surrounded by polyacrylamide through both ionic and covalent bonding, forming a tight spatial network structure with excellent adsorption bridging properties. The presence of covalent bonds enhances the interfacial interaction between the inorganic and organic phases of the flocculant, forming a stable chemical structure and resulting in stronger flocculation stability during water treatment.

[0039] The bonding strength between the organic polymer and inorganic components at the interface significantly affects the flocculation effect. If the bonding strength between the interfaces is weak, macroscopic phase separation will occur under strong hydraulic shear, resulting in a loss of performance advantages. The flocculant prepared in this invention is made from inorganic and organic components through chemical modification. It effectively utilizes the high positive charge density of inorganic flocculants and the bridging effect of organic polymer flocculants, retaining the advantages of both inorganic and organic components. The combination also produces a new synergistic effect, offering advantages such as low dosage, rapid floc formation, good flocculation effect, and low cost.

[0040] One key aspect of the technical solution of this invention is the synergistic effect of charge neutralization by inorganic components and adsorption bridging by organic components to generate flocculation and sedimentation. Under the action of electrostatic attraction and adsorption, inorganic components attract particles and metal ion polymers in the water system to the center of the flocculant. Under the adsorption bridging effect of long-chain polyacrylamide, the particles are further fixed by the flocculant, and the high-molecular-weight organic long chains squeeze out the free water around the particles, forming large molecular clusters of flocculant. Thus, during the coagulation process, large and dense flocs can be generated, greatly improving the flocculation effect. At the same time, under the synergistic effect of compressed double electric layer, adsorption charge neutralization, and adsorption bridging, the inorganic components become positively charged. The positive charge squeezes into the diffusion layer of negatively charged suspended particles, reducing the shear potential of the solution system and destabilizing and aggregating colloidal particles. Polyaluminum chloride has high-charge polymeric ring chains with a Keggin structure, which can reduce the potential barrier with opposite charges, play the role of adsorption charge neutralization, and attract negatively charged colloidal suspensions. The organic long chains of the flocculant bridge the adsorbed particles, thereby accelerating the removal of suspended colloids and the sedimentation rate.

[0041] Furthermore, another key aspect of the technical solution of this invention lies in the selective adsorption and filtration of metal ion impurities by the polymeric flocculant. Polyaluminum chloride can reduce the surface electronegativity of the flocculant and simultaneously compress the surface double layer, promoting the adsorption and filtration of positively charged Mn. 2+ The Mn group on the polyacrylamide chain undergoes opposite charge attraction and aggregation, with the Mn group on the long chain... 2+ The quantity increases, and the water system near the flocculants contains Mn 2+ The reduction in the thickness of the electric double layer on the surface of the flocculant leads to a stronger charge attraction, which attracts metal ion impurities with electronegativity greater than that of manganese ions (Pd > Ni ≥ Cu > Fe ≥ Co > Zn > Mn). At the same time, the hydroxyl groups on the long organic chains are highly protonated, changing from -OH to -OH. 2+ This makes Mn, which has weaker electronegativity, 2+ The inventors define this process, excluding the flocculants, as the "electrostatic bridging effect," thus ensuring that the polymer flocculants do not reduce the Mn content in the water system. 2+ Ion concentration. First, the charged polymers in the flocculant interact with solid particles in the water system to form an adsorption layer. Because the organic polymer chains have many ionic groups, they can adsorb onto the charged areas on the surface of the solid particles, forming a layer of organic polymer covering that prevents collisions and aggregation between particles, thus playing a role in stabilizing dispersion. Next, the polymer flocculants mainly produce an "electrostatic bridging effect." At the same time, the long organic chains of the polymer squeeze out the free water around the particles, and the flocculant forms large molecular clusters, which reduces the distance between particles, enhances the attraction between particles, and produces large and dense flocs, improving the flocculation effect. Finally, the interaction forces between particles increase, the bridging gradually enlarges, the aggregated flocs gradually become larger and larger, and the density also increases, eventually reaching the conditions for precipitation to form precipitate.

[0042] The beneficial effects of this invention are:

[0043] This invention has a good flocculation and adsorption effect, which can effectively remove impurities in electrolyte raw materials, especially metal ion impurities, and can avoid the loss of manganese ions in the process of removing metal ion impurities. Detailed Implementation

[0044] The present invention will be further described clearly and in detail below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0045] Unless otherwise specified, all raw materials used in the embodiments of the present invention are commercially available or obtainable by those skilled in the art; unless otherwise specified, all methods used in the embodiments of the present invention are methods mastered by those skilled in the art.

[0046] Example 1

[0047] A method for preparing a polymeric flocculant.

[0048] (1) Polyaluminum chloride, polyacrylamide and silica were mixed evenly in a mass ratio of 1:7.8:5. 150% VOL of distilled water was added to the mixture and 0.9 wt% of potassium persulfate was added. The mixture was carried out for 180 min at a temperature of 45℃ and a nitrogen atmosphere to prepare the precursor.

[0049] (2) Tetrabutyl titanate with a purity ≥99.0%, anhydrous ethanol, 65% nitric acid and polyaluminum iron silicate are mixed evenly in a volume ratio of 1:1.8:1:0.1, dried at 120℃ for 240 min, and ground to 100 mesh to prepare a prepolymer.

[0050] (3) Mix the precursor and prepolymer at a mass ratio of 1:0.1 and emulsify them by ultrasonication at 360W for 120 minutes at a temperature of 45℃ to prepare a polymeric flocculant.

[0051] The performance of the polymeric flocculant prepared in the examples was characterized, and the specific characterization results are as follows.

[0052] Manganese dioxide sulfuric acid leaching solution from soft manganese ore rhodochrosite was collected as an industrial sample solution. A 0.5 mol / L manganese sulfate solution was prepared, and 0.5 g ferric sulfate, 0.5 g nickel chloride, 0.3 g copper sulfate, 0.3 g zinc chloride, and 1.0 g calcium nitrate were added to the solution to prepare a laboratory sample solution. A polymeric flocculant and the sample solution were mixed at a mass ratio of 3:97 and stirred for 20 min, followed by filtration. The ion concentration and average particle size of the filter residue in the solution system before and after treatment were measured. The removal rate of impurity metal ions, the retention rate of manganese ions, and the average particle size of agglomerated particles were characterized. The characterization results are as follows.

[0053] Impurity metal ion removal rate Manganese ion retention rate Average particle size of agglomerated particles Industrial sample solution 97.83％ 98.45％ 0.68mm Laboratory sample solution 97.95％ 98.46％ 0.39mm

[0054] Formulating a mixture containing different impurity ions (Fe) 3+ Gradient tests were conducted on laboratory sample solutions to determine the concentration threshold for impurity removal, and to characterize impurity ions (Fe). 3+ The removal rates and corresponding manganese ion retention rates at different concentrations are characterized as follows.

[0055]

[0056] In addition, the sample solution of the present invention was mixed with a suspension (the suspended matter being fine sand with a particle size of about 120 mesh) at a mass ratio of 3:97, stirred for 20 minutes and then filtered. The removal rate of solid particles in the suspension was characterized and calculated. The filter residue obtained by filtration was characterized and its average particle size was detected. The characterization results are as follows.

[0057] Solid particulate matter removal rate Average particle size of filter residue 99.57％ 0.92mm

[0058] Example 2

[0059] A method for preparing a polymeric flocculant.

[0060] (1) Mix polyaluminum chloride, polyacrylamide and silica in a mass ratio of 1:8:5, add 155% VOL of distilled water according to the volume of the mixture, add 1.0 wt% of potassium persulfate according to the mass of the mixture, and carry out the mixture at 50°C under a nitrogen atmosphere for 150 min to prepare the precursor.

[0061] (2) Tetrabutyl titanate with a purity ≥99.0%, anhydrous ethanol, 65% nitric acid and polyaluminum iron silicate solution are mixed evenly in a volume ratio of 1:2:1:0.2, dried at 125℃ for 210 min, and ground to 150 mesh to prepare prepolymer.

[0062] (3) Mix the precursor and prepolymer at a mass ratio of 1:0.2 and ultrasonically emulsify at a temperature of 47℃ for 90 min to prepare a polymeric flocculant.

[0063] The performance of the polymeric flocculant prepared in the examples was characterized, and the specific characterization results are as follows.

[0064] Manganese dioxide sulfuric acid leaching solution from soft manganese ore rhodochrosite was collected as an industrial sample solution. A 0.5 mol / L manganese sulfate solution was prepared, and 0.5 g ferric sulfate, 0.5 g nickel chloride, 0.3 g copper sulfate, 0.3 g zinc chloride, and 1.0 g calcium nitrate were added to the solution to prepare a laboratory sample solution. A polymeric flocculant and the sample solution were mixed at a mass ratio of 3:97 and stirred for 20 min, followed by filtration. The ion concentration and average particle size of the filter residue in the solution system before and after treatment were measured. The removal rate of impurity metal ions, the retention rate of manganese ions, and the average particle size of agglomerated particles were characterized. The characterization results are as follows.

[0065] Impurity metal ion removal rate Manganese ion retention rate Average particle size of agglomerated particles Industrial sample solution 97.89％ 98.46％ 0.69mm Laboratory sample solution 97.94％ 98.46％ 0.37mm

[0066] Formulating a mixture containing different impurity ions (Fe) 3+ Gradient tests were conducted on laboratory sample solutions to determine the concentration threshold for impurity removal, and to characterize impurity ions (Fe). 3+ The removal rates and corresponding manganese ion retention rates at different concentrations are characterized as follows.

[0067]

[0068] In addition, the sample solution of the present invention was mixed with a suspension (the suspended matter being fine sand with a particle size of about 120 mesh) at a mass ratio of 3:97, stirred for 20 minutes and then filtered. The removal rate of solid particles in the suspension was characterized and calculated. The filter residue obtained by filtration was characterized and its average particle size was detected. The characterization results are as follows.

[0069] Solid particulate matter removal rate Average particle size of filter residue 99.61％ 0.93mm

[0070] Example 3

[0071] A method for preparing a polymeric flocculant.

[0072] (1) Polyaluminum chloride, polyacrylamide and silica were mixed evenly in a mass ratio of 1:8.2:5. 160% VOL of distilled water was added to the mixture and 1.1 wt% of potassium persulfate was added to the mixture. The mixture was subjected to a nitrogen atmosphere at a temperature of 55°C for 120 min to prepare the precursor.

[0073] (2) Tetrabutyl titanate with a purity ≥99.0%, anhydrous ethanol, 65% nitric acid and polyaluminum iron silicate solution are mixed evenly in a volume ratio of 1:2.2:1:0.3, dried at 130℃ for 180 min, and ground to 200 mesh to prepare prepolymer.

[0074] (3) Mix the precursor and prepolymer at a mass ratio of 1:0.3 and ultrasonically emulsify at a temperature of 50℃ for 60 min to prepare a polymeric flocculant.

[0075] The performance of the polymeric flocculant prepared in the examples was characterized, and the specific characterization results are as follows.

[0076] Manganese dioxide sulfuric acid leaching solution from soft manganese ore rhodochrosite was collected as an industrial sample solution. A 0.5 mol / L manganese sulfate solution was prepared, and 0.5 g ferric sulfate, 0.5 g nickel chloride, 0.3 g copper sulfate, 0.3 g zinc chloride, and 1.0 g calcium nitrate were added to the solution to prepare a laboratory sample solution. A polymeric flocculant and the sample solution were mixed at a mass ratio of 3:97 and stirred for 20 min, followed by filtration. The ion concentration and average particle size of the filter residue in the solution system before and after treatment were measured. The removal rate of impurity metal ions, the retention rate of manganese ions, and the average particle size of agglomerated particles were characterized. The characterization results are as follows.

[0077] Impurity metal ion removal rate Manganese ion retention rate Average particle size of agglomerated particles Industrial sample solution 97.83％ 98.44％ 0.68mm Laboratory sample solution 97.93％ 98.47％ 0.41mm

[0078] Formulating a mixture containing different impurity ions (Fe) 3+Gradient tests were conducted on laboratory sample solutions to determine the concentration threshold for impurity removal, and to characterize impurity ions (Fe). 3+ The removal rates and corresponding manganese ion retention rates at different concentrations are characterized as follows.

[0079]

[0080] In addition, the sample solution of the present invention was mixed with a suspension (the suspended matter being fine sand with a particle size of about 120 mesh) at a mass ratio of 3:97, stirred for 20 minutes and then filtered. The removal rate of solid particles in the suspension was characterized and calculated. The filter residue obtained by filtration was characterized and its average particle size was detected. The characterization results are as follows.

[0081] Solid particulate matter removal rate Average particle size of filter residue 99.59％ 0.93mm

[0082] Comparative Example 1

[0083] A method for preparing a polymeric flocculant, the specific preparation method of which is the same as in Example 2, except that the prepolymer unique to this invention is not prepared and used, but the polymeric flocculant is prepared. The specific operation is as follows:

[0084] A method for preparing a polymeric flocculant involves mixing polyaluminum chloride, polyacrylamide, and silica in a mass ratio of 1:8:5, adding 155% VOL of distilled water (by volume of the mixture), and adding 1.0 wt% of potassium persulfate (by mass of the mixture). The mixture is then subjected to a nitrogen atmosphere at 50°C for 150 min to prepare a precursor. Finally, the precursor is ultrasonically emulsified at 47°C for 90 min to prepare the polymeric flocculant.

[0085] The prepared polymeric flocculant was characterized in the same way as in Example 2, and the specific characterization results are as follows.

[0086]

[0087]

[0088] Comparing the characterization results above with those of Example 2, it was found that the water sample after sedimentation of the polymeric flocculant prepared in the comparative example still contained a large number of reducing impurities, and the removal rate of metal ions was significantly reduced. According to the inventors' research and observation, the molecular weight of organic flocculants is smaller than that of synthetic organic flocculants, the charge density is lower, the water solubility is poor, and they are easily biodegraded, resulting in poorer coagulation effect. Therefore, modifying them to synthesize inorganic-organic hybrid flocculants can greatly improve the flocculation efficiency of flocculants.

[0089] Comparative Example 2

[0090] A method for preparing a polymeric flocculant, the specific preparation method of which is the same as in Example 2, except that the tetrabutyl titanate unique to this invention is not used, and the preparation of the polymeric flocculant is carried out as follows:

[0091] A method for preparing a polymeric flocculant.

[0092] (1) Mix polyaluminum chloride, polyacrylamide and silica in a mass ratio of 1:8:5, add 155% VOL of distilled water according to the volume of the mixture, add 1.0 wt% of potassium persulfate according to the mass of the mixture, and carry out the mixture at 50°C under a nitrogen atmosphere for 150 min to prepare the precursor.

[0093] (2) Mix anhydrous ethanol, 65% nitric acid and polyaluminum iron silicate solution in a volume ratio of 2:1:0.2, dry at 125℃ for 210 min, grind and crush to 150 mesh to prepare prepolymer;

[0094] (3) Mix the precursor and prepolymer at a mass ratio of 1:0.2 and ultrasonically emulsify at a temperature of 47℃ for 90 min to prepare a polymeric flocculant.

[0095] The prepared polymeric flocculant was characterized in the same way as in Example 2, and the specific characterization results are as follows.

[0096]

[0097]

[0098] Comparing the characterization results above with those of Example 2, it was found that the polymeric flocculant prepared in the comparative example had a higher metal ion removal rate, but the manganese ion retention rate was also reduced, and the resulting flocs were too small and unstable. This proves that the flocculant prepared in the comparative example lacks selectivity. According to the inventor's research and testing, the bonding strength between the interface of the organic polymer and the inorganic component has a significant impact on the flocculation effect. If the bonding strength between the interfaces is weak, macroscopic phase separation will occur under strong hydraulic shear, resulting in the loss of performance advantages. In hybrid flocculants with ionic bonding, when the concentration is too low, some inorganic components and organic components will ionize, leading to changes in the structure of the polymeric flocculant and reducing the flocculation stability. The addition of tetrabutyl titanate in the technical solution of this invention can connect the interface between the inorganic and organic phases through covalent bonding. The connection is made through both ionic and covalent bonding, presenting a tight spatial network structure with excellent adsorption bridging performance. The presence of covalent bonds makes the flocculant have stronger flocculation stability in the water treatment process and can also continue to generate electrostatic bridging effect, so that manganese ions in the water system will not be filtered by flocculation.

[0099] Comparative Example 3

[0100] A method for preparing a polymeric flocculant, the specific preparation method of which is the same as in Example 2, except that the precursor unique to this invention is not prepared and used, and the polymeric flocculant is prepared. The specific operation is as follows:

[0101] A method for preparing a polymeric flocculant involves mixing tetrabutyl titanate (purity ≥99.0%), anhydrous ethanol, 65% nitric acid, and a polymeric aluminum iron silicate solution at a volume ratio of 1:2:1:0.2, drying at 125°C for 210 min, grinding and crushing to 150 mesh to prepare a prepolymer, and ultrasonically emulsifying at 47°C for 90 min to prepare the polymeric flocculant.

[0102] The prepared polymeric flocculant was characterized in the same way as in Example 2, and the specific characterization results are as follows.

[0103]

[0104]

[0105] Comparing the characterization results above with those of Example 2, it was found that the polymeric flocculant prepared in the comparative example has a strong metal ion removal rate, but a very low manganese ion retention rate. According to the inventors' research and observation, under the adsorption bridging effect of long-chain polyacrylamide, suspended particles are fixed by the flocculant, and the flocculant forms large molecular clusters. During the coagulation process, large and dense flocs are generated, which have a high flocculation effect, but do not release the adsorbed manganese ions, resulting in the loss of manganese ions in the solution.

[0106] Comparative Example 4

[0107] A commercially available flocculant was characterized using the same performance methods as in Example 2. The specific characterization results are as follows.

[0108]

[0109] Analysis of the above characterization results clearly shows that manganese ions are difficult to retain in water samples after sedimentation by commercially available flocculants. Through research and testing by the inventors, it has been found that the flocculant prepared by this invention combines the advantages of both organic and inorganic flocculants through modification, and can selectively settle metal ions with high sedimentation efficiency and more stable flocculent precipitate, thus achieving the expected technical effect.

Claims

1. A method for preparing a polymeric flocculant, characterized in that, The method includes: (1) Inorganic polymer coagulant, linear polymer and silica are mixed evenly in proportion to form a mixture, dissolved in water, and an initiator is added to carry out a low-temperature thermal reaction to prepare a precursor; (2) Mix the crosslinking agent, ethanol, nitric acid and polymeric aluminum iron silicate in proportion, dry and grind to prepare a prepolymer; (3) Mix the precursor and prepolymer in a certain proportion, emulsify by ultrasonication, and prepare a polymeric flocculant; The inorganic polymeric flocculant mentioned in step (1) is polyaluminum chloride; The linear polymer mentioned in step (1) is polyacrylamide; The crosslinking agent in step (2) is tetrabutyl titanate.

2. The method for preparing a polymeric flocculant according to claim 1, characterized in that, The inorganic polymer flocculant, linear polymer and silica mentioned in step (1) are mixed in a mass ratio of 1: (7.8-8.2): (4.8-5.2).

3. The method for preparing a polymeric flocculant according to claim 1, characterized in that, The initiator in step (1) is potassium persulfate; The amount of potassium persulfate used is 0.9 to 1.1 wt% of the mixture.

4. The method for preparing a polymeric flocculant according to claim 1, characterized in that, The low-temperature thermal reaction in step (1) is carried out in a protective atmosphere, with the reaction temperature controlled at 45-55 °C and the reaction time at 120-180 min.

5. The method for preparing a polymeric flocculant according to claim 1, characterized in that, The nitric acid concentration in step (2) is a 62-68 wt% nitric acid aqueous solution.

6. A method for preparing a polymeric flocculant according to claim 1 or 5, characterized in that, In step (2), the crosslinking agent, ethanol, nitric acid, and polyaluminum ferric silicate are mixed in a mass ratio of 1:(1.8-2.2):(0.9-1.1):(0.1-0.3). The drying and grinding process in step (2) involves drying at 120-130 ℃ for 180-240 min, followed by grinding and crushing to obtain a 100-200 mesh prepolymer.

7. The method for preparing a polymeric flocculant according to claim 1, characterized in that, The precursor and prepolymer in step (3) are mixed in a mass ratio of 1:(0.1 to 0.3).

8. The method for preparing a polymeric flocculant according to claim 1, characterized in that, The ultrasonic emulsification in step (3) is performed at 45-50 ℃ for 60-120 min.

9. A polymeric flocculant prepared by the method of any one of claims 1 to 8.

Images