Liquid type super-high cation water purifier for treating mine wastewater and preparation and application thereof

Abstract

The application discloses a liquid type super-high cation water purifying agent for treating mine wastewater, which is prepared by stably dispersing AM-DM oil emulsion copolymer and PDM homopolymer in an oily solvent under the action of an emulsifier; the water purifying agent comprises the following components: 11-15 parts of AM-DM oil emulsion copolymer containing AM-DM copolymer, 60-65 parts of PDM homopolymer, 2-3 parts of emulsifier, and the rest is an oily solvent; the AM-DM oil emulsion copolymer is obtained by emulsifying the AM-DM copolymer in the oily solvent. The super-high cation water purifying agent can improve the molecular weight and viscosity of the water purifying agent product, and can also keep the stability and uniformity of the super-high cation charge density, is used for treating mine wastewater, can significantly improve the treatment effect, makes the supernatant of the treated wastewater clear and transparent, can greatly reduce the treatment cost, and has a positive market application value.

Description

Technical Field

[0001] This invention relates to the field of water purification agents for treating mine wastewater, specifically a liquid-type ultra-high cationic water purification agent for treating mine wastewater, as well as the preparation and application of the water purification agent. Background Technology

[0002] Mine wastewater is wastewater discharged during the mining process. It contains not only suspended solids such as gangue and coal dust (approximately 7%–8%), but also high levels of heavy metals and organic matter such as ammonia nitrogen, phosphorus, and COD. To maintain ecological balance and protect the environment, the wastewater must be treated to meet discharge standards before discharge. Currently, conventional deep cone sedimentation technology is commonly used to treat mine wastewater, often in conjunction with water purification agents. Rapid settling achieves clarification and purification. However, due to the large volume and fluctuating quality of mine wastewater, coupled with constraints imposed by the mine's geographical environment and limited space at construction sites, the treated wastewater exhibits significant fluctuations, particularly in suspended solids (turbidity), directly impacting discharge.

[0003] Coal powder or mineral powder particles in mine wastewater generally carry a negative charge. However, cationic polyacrylamide (PAM), due to its large molecular weight and relatively low charge density, will cause the water to become stringy and sticky after treatment. Even with reduced dosage, the clarified liquid will still be sticky and the flocs will disperse, making it unsuitable for mine wastewater treatment. Anionic polyacrylamide (PAM) cannot be used alone as a water purification agent for mine wastewater because it will repel the charges in the wastewater, failing to perform adsorption, sweeping, and flocculation functions. Therefore, currently, anionic PAM and polyaluminum chloride (PAC) are often used in combination as water purification agents. PAC provides high ionicity, and PAM provides high molecular weight. Through their combination, they bridge and neutralize the charges in the mine wastewater, achieving the purification purpose. However, even after treatment with anionic PAM and PAC, mine wastewater still suffers from suspended fine particulate matter and high turbidity. To further reduce turbidity and ensure effective purification, the dosage of PAM and PAC must be increased. However, the dosage of PAM and PAC must be strictly adhered to, and in actual wastewater treatment, the harsh operating environment, the tendency of PAC to absorb moisture and clump, and the often rough dosing procedures result in significant deviations in dosage ratios, leading to unstable treatment results and frequent non-compliance. Developing a liquid-type single-agent solution with good purification effects for mine wastewater would be highly beneficial for promoting the application of automated wastewater treatment systems in mine wastewater management and improving the overall level of mine wastewater treatment. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention provides a liquid ultra-high cationic water purifier for treating mine wastewater. This purifier increases the molecular weight and viscosity of the product while maintaining the stable and uniform ultra-high cationic charge density. When used for treating mine wastewater, it significantly improves the treatment effect, resulting in a clear and transparent supernatant. It also greatly reduces treatment costs and has significant market application value.

[0005] To achieve the above objectives, the present invention provides a liquid ultra-high cationic water purifier for treating mine wastewater, which is mainly prepared by stably dispersing AM-DM oily emulsion copolymer and PDM homopolymer in an oily solvent under the action of an emulsifier; the water purifier includes the following components:

[0006] It contains 11-15 parts of AM-DM copolymer, 60-65 parts of PDM homopolymer, 2-3 parts of emulsifier, and the remainder is oil solvent;

[0007] AM-DM oily emulsion copolymers are obtained by emulsifying AM-DM copolymers with oily solvents;

[0008] The mass of AM-DM copolymer shall not exceed 50% of the total mass of AM-DM oily emulsion copolymer, and the mass of AM-DM copolymer and PDM homopolymer shall not exceed 50% of the total mass of water purification agent.

[0009] The rotational viscosity of AM-DM copolymers ranges from 60,000 to 270,000 mPa·s; the rotational viscosity of PDM homopolymers is above 60,000 mPa·s.

[0010] As a limitation of the above technical solution, the cationicity of the AM-DM copolymer is ≥60%, the cationicity of the water purification agent is ≥85%, and the molecular weight of the water purification agent is 1 million to 3 million.

[0011] Cationicity refers to cation charge density, which is an indicator describing the number of cations in a cationic polymer solution. Its magnitude reflects the charge and dissociation degree of the cationic polymer. Generally, the cationicity of cationic solutions is between 20% and 50%. This application breaks through the conventional limitation of cationicity by using AM-DM copolymer with cationicity ≥60% and PDM homopolymer for composite emulsification to form a liquid water purification agent with cationicity ≥85%. While maintaining the stability and uniformity of ultra-high cationic charge density, it significantly improves the molecular weight and viscosity of the water purification agent product, achieving the combination of high cationicity and high molecular weight in a single liquid water purification agent product.

[0012] Monomer DM has 100% cationic charge, but its activity is poor due to its structure. Homopolymer PDM, on the other hand, struggles to achieve ultra-high molecular weights above 3 million. Therefore, this invention copolymerizes AM with DM using AM as the backbone, resulting in an AM-DM copolymer with ultra-high molecular weights of 6 to 12 million. However, since AM does not contain cationic charge, the AM-DM copolymer significantly reduces the cationic charge density. By combining the AM-DM copolymer with PDM homopolymer, both high cationicity and high molecular weight are achieved. However, polymer-based water treatment agents typically require prior dissolution and dilution before use and cannot be added directly; otherwise, aggregation will occur, hindering the treatment effect. To address the solubility issue, this invention involves simultaneously adding an oily solvent for emulsification during the preparation of the AM-DM copolymer. The AM-DM oily emulsion copolymer is then combined with a PDM homopolymer for further emulsification, allowing the two polymers to fully combine and uniformly disperse in the oily solvent. This results in a liquid water purifier that does not require prior dissolution and can be added directly for use. This water purifier is readily and uniformly dispersed in the aqueous phase during use, effectively synergistically combining the ultra-high molecular weight advantage of the AM-DM copolymer with the ultra-high cationic charge density advantage of the PDM homopolymer.

[0013] This invention addresses the characteristics of mine wastewater, such as high content of gangue and coal powder, high turbidity, and large volume. It achieves effective treatment of mine wastewater by compounding AM-DM copolymer and PDM homopolymer in a specific ratio. This not only replaces existing treatment methods that combine PAC and PAM polymers, but also offers advantages in ease of use and effectiveness. Specifically, the water treatment agent dissolves quickly and has good stability; it only needs to be added to water and stirred rapidly. The treated wastewater supernatant is clear and transparent, with compact flocs and rapid settling; disturbance does not disrupt the floc structure. The main function of the oil emulsion in the water treatment agent is to encapsulate the two polymers for uniform dispersion, facilitating rapid dissolution during use. To achieve this dispersion, the amount of oil emulsion used should not be less than the amount of AM-DM copolymer and PDM homopolymer. However, excessive addition of oil emulsion is detrimental to cost and can also affect the cationicity and effectiveness of the water treatment agent. Therefore, the amount of oil solvent should be rationally adjusted according to the application requirements.

[0014] In addition, by adjusting the ratio of AM-DM copolymer to PDM homopolymer to suit the characteristics of different wastewaters, different liquid-type ultra-high cationic water purification agents suitable for various polluted wastewaters can be obtained.

[0015] As a limitation of the above technical solution, the AM-DM oily emulsion copolymer is obtained by polymerizing monomers acrylamide and dimethylaminoethyl methacrylate under normal pressure and 95-115°C with the action of an initiator to obtain AM-DM copolymer, and then emulsifying with an oily solvent.

[0016] Preferably, the mass ratio of acrylamide to dimethylaminoethyl methacrylate in the polymerization reaction is 35:70-80.

[0017] As a limitation of the above technical solution, the PDM homopolymer is prepared by polymerization of acrylamide monomer at atmospheric pressure and 110-115°C under the action of an initiator.

[0018] As a limitation of the above technical solution, the initiator is zinc chloride, and the amount of initiator added does not exceed 5% of the amount of monomer used in the polymerization reaction. That is, in the preparation process of AM-DM oily emulsion copolymer, the amount of initiator added does not exceed 5% of the total mass of acrylamide and dimethylaminoethyl methacrylate monomers, and in the preparation process of PDM homopolymer, the amount of initiator added does not exceed 5% of the mass of acrylamide monomer.

[0019] As a limitation of the above technical solution, the emulsifier is selected from at least one of N-dodecyl dimethylamine, N-dodecyl dimethylamine derivatives, and quaternary ammonium salts; the oily solvent is selected from one or more of dearomatic solvent oils D60, D80, D100, or white oil.

[0020] As a limitation of the above technical solution, the water purification agent also includes a cationic surfactant with a mass concentration of no more than 0.05%, and / or a stabilizer with a mass concentration of no more than 0.05%; preferably, the cationic surfactant is dodecyl dimethyl benzyl ammonium chloride, and the stabilizer is thiourea.

[0021] This invention polymerizes two monomers, AM and DM, to obtain AM-DM oily emulsion copolymer and PDM homopolymer, respectively, and further improves the polymerization conditions and other component raw materials in the water purification agent to enhance the performance and advantages of the water purification agent.

[0022] Meanwhile, this invention provides a method for preparing the liquid ultra-high cation water purifier for treating mine wastewater as described above, comprising the following preparation steps:

[0023] a. Preparation of AM-DM oily emulsion copolymer: Weigh acrylamide, dimethylaminoethyl methacrylate, and initiator quantitatively, add them to a reaction vessel, and slowly raise the temperature inside the vessel to 95-115℃ under normal pressure and stirring, then keep it stable to carry out the polymerization reaction. Stop the reaction when the rotational viscosity of the AM-DM copolymer reaches 60,000-270,000 mPa·s, add an oily solvent to fully emulsify, and obtain a uniform AM-DM oily emulsion copolymer; or, after the AM-DM polymerization begins, add an oily solvent while the polymerization reaction is underway, and react for 4-6 hours to obtain a uniform AM-DM oily emulsion copolymer;

[0024] b. Preparation of PDM homopolymer: Weigh out dimethylaminoethyl methacrylate and initiator in a quantitative amount and add them to another reaction vessel. Under normal pressure and stirring, raise the temperature inside the vessel to 110-115℃ and keep it stable to carry out the polymerization reaction. Stop the reaction when the rotational viscosity of the reactants reaches 60000mPa·s or more to obtain PDM homopolymer.

[0025] c. Preparation of water purification agent: AM-DM oily emulsion copolymer and PDM homopolymer are added to an emulsification tank in proportion, followed by oily solvent, emulsifier, and the required cationic surfactant and stabilizer. The mixture is stirred at high speed to emulsify the mixture uniformly, resulting in a uniform and stable milky white viscous liquid, which is a liquid ultra-high cationic water purification agent for treating mine wastewater. Preferably, the stirring speed is 30-60 rad / min.

[0026] In actual production, the preparation of AM-DM oily emulsion copolymers can be carried out by first obtaining AM-DM copolymers that meet the viscosity requirements and then adding oily emulsions for emulsification, or by adding oily emulsions as the polymerization reaction proceeds after the AM-DM copolymers have started to polymerize, thereby obtaining AM-DM oily emulsion copolymers that meet the requirements.

[0027] As a limitation of the above technical solution, the mass of AM-DM copolymer accounts for 40-50% of the total mass of AM-DM oily emulsion copolymer; the mass of AM-DM copolymer and PDM homopolymer accounts for 40-50% of the total mass of water purification agent.

[0028] From a production cost perspective, it is more appropriate to control the amount of oily emulsion used to make the polymer mass ratio 40-50%.

[0029] The liquid-type ultra-high cation water purifier of the present invention does not require a special environment for preparation and is simple and convenient to operate. Since all raw materials used are liquid, various raw materials can be added and reacted precisely, and continuous preparation can be carried out to achieve automated production, which is conducive to the promotion and application of water purifier.

[0030] Meanwhile, the present invention also provides the application of the liquid ultra-high cationic water purifier as described above for treating mine wastewater. This water purifier is suitable for treating coal preparation wastewater in the coal mining industry. The recommended dosage of the water purifier for wastewater with suspended solids content between 3% and 5% is 50 to 100 mg / L. The suspended solids content of the treated wastewater meets the emission limits for pollutants in coal mining wastewater in Table 2 of GB20426-2006 Coal Industry Pollutant Emission Standard. Preferably, the suspended solids content of the treated wastewater is <50 mg / L.

[0031] When the water purification agent of the present invention is used, only one liquid water treatment agent needs to be added to achieve the two functions of neutralizing the charge of charged particles in wastewater and flocculating and settling suspended solids. The supernatant of the treated wastewater is clear and transparent, the flocs are compact, the settling speed is fast, and the state of the flocs will not be destroyed after disturbance.

[0032] In summary, the liquid ultra-high cationic water purifier of this invention achieves the dual advantages of high cationicity and high molecular weight in a single water purifier product. Compared with the existing combined use of PAC and PAM agents, it not only significantly improves water treatment effect and reduces effluent turbidity, but also simplifies operation, ensures stable operation while improving the operating environment and increasing operating efficiency. Furthermore, it greatly reduces operating costs. Specifically, when the effective content (i.e., the total mass of AM-DM copolymer and PDM homopolymer in the water purifier product) of this invention is 40%, the molecular weight is between 1 million and 3 million, and the charge density reaches approximately 90%, the operating cost is 0.578 yuan / ton of water, which is significantly lower than the 2.436 yuan / ton of water operating cost of the existing PAC+PAM (anionic) combination. This demonstrates significant application value for the treatment of mine wastewater. Attached Figure Description

[0033] Figure 1 Photographs of the AM-DM oily emulsion copolymer, PDM homopolymer, and water purification agent samples of the present invention;

[0034] Figure 2 Photographs of the water quality after treating mineral processing wastewater with reagent 2 (Comparative Example 2);

[0035] Figure 3 Photographs of the water quality after treating mineral processing wastewater with reagent 1 (Comparative Example 1);

[0036] Figure 4 Photos of water quality after treating mineral processing wastewater with the water purification agent of this invention;

[0037] Figure 5 Photos from the first day of the pilot test;

[0038] Figure 6 Photos taken on the second day of the pilot test. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0040] The raw materials used in the following examples and comparative examples are all typical products purchased from the market. The quantitative experiments were all repeated three times, and the results were averaged.

[0041] Example

[0042] This embodiment relates to the preparation of a liquid ultra-high cation water purifier, and the specific operation is as follows.

[0043] a. Preparation of AM-DM oily emulsion copolymer: Weigh acrylamide, dimethylaminoethyl methacrylate, and initiator quantitatively, add them to a reaction vessel, and slowly raise the temperature inside the vessel to 95-115℃ under normal pressure and stirring, then keep it stable to carry out the polymerization reaction. Stop the reaction when the rotational viscosity of the AM-DM copolymer reaches 60,000-270,000 mPa·s, add an oily solvent to fully emulsify, and obtain a uniform AM-DM oily emulsion copolymer; or, after the AM-DM polymerization begins, add an oily solvent while the polymerization reaction is underway, and react for 4-6 hours to obtain a uniform AM-DM oily emulsion copolymer;

[0044] b. Preparation of PDM homopolymer: Weigh out dimethylaminoethyl methacrylate and initiator in a quantitative amount and add them to another reaction vessel. Under normal pressure and stirring, raise the temperature inside the vessel to 110-115℃ and keep it stable to carry out the polymerization reaction. Stop the reaction when the rotational viscosity of the reactants reaches 60000mPa·s or more to obtain PDM homopolymer.

[0045] c. Preparation of water purification agent: Add AM-DM oily emulsion copolymer and PDM homopolymer to the emulsification tank in proportion, then add oily solvent, emulsifier, and the required cationic surfactant and stabilizer. Stir at high speed, controlling the stirring speed to 30-60 rad / min, so that the mixture is uniformly emulsified to obtain a uniform and stable milky white viscous liquid, which is the liquid-type ultra-high cationicity water purification agent.

[0046] The composition of the water purification agents in different embodiments is shown in Table 1 below.

[0047] Table 1

[0048]

[0049]

[0050] Note: The preparation conditions of AM-DM oily emulsion copolymer and PDM homopolymer provided in the above embodiments are fixed and only the polymerization time is changed for the convenience of experiments and comparisons. In actual production, the preparation conditions of water purification agents, including the preparation and compounding of AM-DM oily emulsion copolymer and PDM homopolymer, can be adjusted within a certain range. Specifically, the ratio of AM to DM in the AM-DM polymerization reaction can be in the range of 35:70 to 80 by mass, and the polymerization temperature can be in the range of 95 to 115°C; the polymerization temperature of the DM polymerization reaction can be in the range of 110 to 115°C, and the amount of oily solvent added can be adjusted according to product requirements, etc.

[0051] The charge density, viscosity, and molecular weight of the AM-DM oily emulsion copolymer, PDM homopolymer, and water purification agent prepared in different embodiments were measured respectively.

[0052] Charge density testing is based on standard Q / LJSW1012001-2023(4.6).

[0053] Viscosity was measured using a rotational viscometer, and the testing standard was in accordance with Q / LJSW1012001-2023(4.3).

[0054] The standard for relative molecular weight determination is based on GB / T31246-2014(5.2).

[0055] According to the above testing standards or methods, the performance indicators of the water purification agents in each embodiment were determined, as shown in Table 2 below; the appearance morphology of AM-DM oily emulsion copolymer, PDM homopolymer and water purification agent are shown in the attached figure. Figure 1 As shown.

[0056] Table 2

[0057]

[0058] Comparative Example

[0059] The comparative examples involve existing water treatment agents and water purification agents different from those of the present invention.

[0060] Comparative Example 1

[0061] The existing water treatment agents use 20% PAC solution (a solution made by dissolving solid PAC to a 20% wt concentration, with the solid PAC being a commercially available product with a 28% concentration) + 1.5‰ anionic PAM solution (a solution made by dissolving commercially available solid anionic PAM with a molecular weight of 16 million to a 1.5‰ concentration).

[0062] Comparative Example 2

[0063] Existing water treatment agents use a 1.5‰ cationic PAM solution (dissolved from commercially available solid cationic PAM with a molecular weight of 10 million to 12 million into a 1.5‰ solution).

[0064] Comparative Example 3

[0065] The difference between this comparative example and the previous example lies in the ratio of the amount of AM-DM oily emulsion copolymer to PDM homopolymer used in the water purification agent.

[0066] Comparative Example 3-1: 63 kg of AM-DM oily emulsion copolymer (containing 25.9 kg of AM-DM copolymer), 30 kg of PDM homopolymer, 4 kg of N-dodecyl dimethylamine, and 3 kg of dearomatic solvent oil D80 were used for composite emulsification. All other preparation conditions were the same as in Example 1, resulting in an oily emulsion with a viscosity of 270,000 mp·s, a cationicity of 72%, and a molecular weight of 8 million.

[0067] Comparative Example 3-2: 12 kg of AM-DM oily emulsion copolymer (containing 4.9 kg of AM-DM copolymer), 83 kg of PDM homopolymer, 3 kg of N-dodecyl dimethylamine, and 2 kg of dearomatic solvent oil D80 were used for composite emulsification. All other preparation conditions were the same as in Example 1, resulting in an oily emulsion with a viscosity of 37,000 mp·s, cationicity of 95%, and molecular weight of 600,000.

[0068] Comparative Example 4

[0069] The difference between this comparative example and the previous one is that the viscosity of the AM-DM oily emulsion copolymer and PDM homopolymer in the water purification agent does not meet the requirements.

[0070] Comparative Example 4-1: The preparation conditions of the AM-DM oily emulsion copolymer were changed: the polymerization reaction time was 3 hours, and the proportions of other materials and reaction conditions remained unchanged (same as in Example 1), resulting in an oily emulsion with a viscosity of 10,000 mp.s, a cationicity of 90%, and a molecular weight of 50,000.

[0071] Comparative Example 4-2: By changing the preparation conditions of PDM homopolymer and controlling the polymerization reaction temperature between 130 and 150°C, the reaction was violent and the material rapidly gelled, resulting in a viscous, blocky material that could not be processed further.

[0072] The wastewater treatment effects of the comparative examples of water purification agents, existing reagents, and different water purification agents were compared. Small-scale tests were conducted using coal mine beneficiation wastewater as the raw water to observe the wastewater treatment phenomena and effects.

[0073] Raw water quality: Suspended solids concentration 50381 mg / L. The suspended solids detection method was gravimetric method, according to GB / T 11901.

[0074] Experimental steps: (1) For each group of experiments, three portions of the same volume (usually 250 mL or 1000 mL) of wastewater to be treated are measured and parallel experiments are conducted.

[0075] (2) Add water purification agent according to Table 3, stir slowly clockwise for 5 to 10 seconds, let stand, and observe the condition of wastewater flocs and settling speed.

[0076] Table 3

[0077]

[0078] As can be seen from the experimental phenomena and water treatment results in Table 3, the cationic PAM in Comparative Example 2 has a large molecular weight and a relatively low charge density. The treated water exhibits a stringy, viscous texture, as shown in the attached figure. Figure 2 As shown, the flocs dispersed after the dosage was reduced, and the clear liquid remained viscous, so cationic PAM is not suitable for the treatment of mine wastewater.

[0079] In Comparative Example 1, PAC was used in combination with anionic PAM to treat mine wastewater. The main function of PAC was to provide high ionization, while the main function of anionic PAM was to provide high molecular weight. The two combined to bridge and neutralize the charges of charged particles in the wastewater, thereby purifying the water. However, some fine particulate matter remained suspended in the treated wastewater, resulting in high turbidity, as shown in the attached figure. Figure 3 As shown.

[0080] The water purification agent of this invention treats mineral processing wastewater with only one agent, achieving the neutralization of charged particles and the flocculation and sedimentation of suspended solids in the wastewater. The supernatant of the treated wastewater is clear and transparent, as shown in the attached figure. Figure 4 As shown, the flocs are compact, settle quickly, and do not break down after disturbance.

[0081] Based on the above small-scale test results, a field test was conducted on wastewater at a coal preparation plant in Guizhou as the test base. The wastewater was then compared with the polyaluminum chloride (PAC) and PAM (anionic) used on site, and the operating costs were calculated.

[0082] On-site pilot test

[0083] Test method: continuous operation, tracking 24-hour operation data, and taking the average value for data analysis and cost accounting.

[0084] Experimental steps:

[0085] (1) On the first day, the dosage of on-site reagents was adjusted to stabilize the effluent quality, and the on-site operation was monitored. Specifically, the PAC preparation tank contained PAC reagent with a dissolved concentration of 20% wt, and the PAC dosing pump was set to a dosing rate between 650 and 700 mg / L; the PAM preparation tank contained anionic PAM reagent with a dissolved concentration of 1.5‰ wt, and the PAM dosing pump was set to a dosing rate between 10 and 20 mg / L. The system was operated stably for 24 hours, and samples were taken every 4 hours to test the effluent suspended solids concentration, and the dosing pump flow rate and wastewater flow rate were recorded.

[0086] (2) On the second day, clean the original PAC preparation tank, which is used to prepare and store the water purification agent product of this invention (the specific formula is as in Example 1). The concentration of the solution is 10%wt (i.e., take 10kg of liquid water purification agent product and add water to make 100kg solution). The original PAC dosing pump is still used for dosing. The dosage is adjusted to 70-80mg / L. Only the water purification agent is used. The system is run stably for 24 hours. The flocs and the quality of the effluent are observed. The concentration of suspended solids in the effluent is sampled every 4 hours. The flow rate of the dosing pump and the flow rate of the wastewater are recorded.

[0087] (3) Organize the data, take the average value, and perform data analysis and cost accounting.

[0088] The experimental data are summarized in Tables 4 and 5:

[0089] Table 4

[0090]

[0091] Table 5

[0092]

[0093] The PAC content used on site is 28% (calculated as aluminum oxide content), with a charge density of about 20-30%. The calculated charge density is 23.74%. The amount used during operation is relatively large, and the output water is unstable due to fluctuations in the quality of the water to be treated. The operating cost is about 2.436 yuan / ton of water.

[0094] The water purification agent of this invention operates stably, and the supernatant is clear and transparent. In the examples, the effective content of the water purification agent is about 40%, the charge density is about 90%, and the molecular weight is higher than that of products using PAC+PAM (anion) combination. It has stronger charge neutralization and coagulation capabilities, and the overall dosage is more economical. The calculated cost is only 0.578 yuan / ton of water, which is significantly more suitable than the combination of PAC and PAM and has better development prospects.

[0095] In summary, the liquid ultra-high cationic water purifier of this invention has an effective content of 40% with a molecular weight between 1 million and 3 million, a charge density of about 90%, and an operating cost of 0.578 yuan / ton of water, which is significantly lower than the operating cost of 2.436 yuan / ton of water for the existing PAC+PAM (anionic) combination. The treated wastewater supernatant is clear and transparent, with compact flocs, fast settling speed, and no disruption of the floc state after disturbance. It has significant application value for the treatment of mining wastewater.

Claims

1. A liquid-type ultra-high cationic water purifier for treating mine wastewater, characterized in that: This water purification agent is mainly prepared by stably dispersing AM-DM oily emulsion copolymer and PDM homopolymer in an oily solvent under the action of an emulsifier; the water purification agent includes the following components, in parts by weight: The product contains 11-15 parts of AM-DM copolymer, 60-65 parts of PDM homopolymer, 2-3 parts of emulsifier, and the remainder is an oil solvent. AM-DM oily emulsion copolymer is obtained by polymerizing monomers acrylamide and dimethylaminoethyl methacrylate under normal pressure and 95~115℃ with an initiator to obtain AM-DM copolymer, which is then emulsified with an oily solvent. PDM homopolymer is prepared by polymerizing dimethylaminoethyl methacrylate at atmospheric pressure and 110-115℃ under the action of an initiator. The mass percentage of AM-DM copolymer in the total mass of AM-DM oily emulsion copolymer is 40-50%; the mass percentage of AM-DM copolymer and PDM homopolymer in the total mass of water purification agent is also 40-50%. The rotational viscosity of AM-DM copolymers is between 60,000 and 270,000 mPa·s; the rotational viscosity of PDM homopolymers is above 60,000 mPa·s.

2. The liquid ultra-high cationic water purifier for treating mine wastewater according to claim 1, characterized in that: The AM-DM copolymer has a cationicity of ≥60%, the water purification agent has a cationicity of ≥85%, and the water purification agent has a molecular weight of 1 million to 3 million.

3. The liquid ultra-high cationic water purifier for treating mine wastewater according to claim 1, characterized in that: In the polymerization reaction of AM-DM copolymer, the ratio of acrylamide to dimethylaminoethyl methacrylate is 35:70~80 by mass.

4. The liquid ultra-high cationic water purifier for treating mine wastewater according to claim 1, characterized in that: The initiator is zinc chloride, and the amount of initiator added does not exceed 5% of the amount of monomer used in the polymerization reaction.

5. The liquid ultra-high cationic water purifier for treating mine wastewater according to claim 1, characterized in that: The emulsifier is selected from at least one of N-dodecyl dimethylamine, N-dodecyl dimethylamine derivatives, and quaternary ammonium salts; the oily solvent is selected from one or more of dearomatic solvent oils D60, D80, D100, or white oil.

6. The liquid ultra-high cationic water purifier for treating mine wastewater according to claim 1, characterized in that: The water purification agent also includes a cationic surfactant at a mass concentration not exceeding 0.05%, and / or a stabilizer at a mass concentration not exceeding 0.05%.

7. The liquid ultra-high cationic water purifier for treating mine wastewater according to claim 6, characterized in that: The cationic surfactant used is dodecyl dimethyl benzyl ammonium chloride, and the stabilizer used is thiourea.

8. A method for preparing a liquid ultra-high cationic water purifier for treating mine wastewater as described in any one of claims 1 to 7, characterized in that, The preparation steps include the following: a. Preparation of AM-DM oily emulsion copolymer: Weigh acrylamide, dimethylaminoethyl methacrylate, and initiator quantitatively, add them to a reaction vessel, and slowly raise the temperature inside the vessel to 95~115℃ under normal pressure and stirring, then keep it stable to carry out the polymerization reaction. Stop the reaction when the rotational viscosity of the AM-DM copolymer reaches 60000~270000mPa·s, add an oily solvent to fully emulsify, and obtain a uniform AM-DM oily emulsion copolymer; or, after the AM-DM polymerization begins, add an oily solvent while the polymerization reaction is underway, and react for 4~6 hours to obtain a uniform AM-DM oily emulsion copolymer; b. Preparation of PDM homopolymer: Weigh out dimethylaminoethyl methacrylate and initiator in a quantitative amount and add them to another reaction vessel. Under normal pressure and stirring, raise the temperature inside the vessel to 110~115℃ and keep it stable to carry out the polymerization reaction. Stop the reaction when the rotational viscosity of the reactants reaches 60000mPa·s or more to obtain PDM homopolymer. c. Preparation of water purification agent: Add AM-DM oily emulsion copolymer and PDM homopolymer to the emulsification tank in proportion, then add oily solvent, emulsifier, and the required cationic surfactant and stabilizer. Stir at high speed to make the mixture uniformly emulsified, and obtain a uniform and stable milky white viscous liquid, which is the liquid ultra-high cationic water purification agent for treating mine wastewater. The stirring speed is 30~60 rad / min.

9. The application of a liquid ultra-high cationic water purifier for treating mine wastewater as described in any one of claims 1 to 7, characterized in that: This water purification agent is suitable for treating coal preparation wastewater in the coal mining industry. The recommended dosage of the water purification agent is 50-100 mg / L when the suspended solids content in the wastewater is between 3% and 5%. The suspended solids content of the treated wastewater meets the requirements of GB20426-2006 Coal Industry Pollutant Emission Standard.

10. The application of the liquid ultra-high cationic water purifier for treating mine wastewater according to claim 9, characterized in that: Wastewater treated with liquid ultra-high cationic water purifier has suspended solids concentrations of <50 mg / L.

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