Self-growing type nano colloid particle suitable for plugging surface pores of coal gasification fine slag as well as preparation method and application of self-growing type nano colloid particle

Abstract

The invention discloses a self-growing type nano colloid particle suitable for plugging surface pores of coal gasification fine slag as well as a preparation method and application of the self-growing type nano colloid particle. The self-growing type nano colloid particle comprises 15-35% of a functional polymeric monomer and cross-linked polymeric monomer medicament, 1-10% of a surfactant, 0.01-0.5% of an initiator, 50-75% of white oil and the balance of distilled water, according to the preparation method disclosed by the invention, accurate regulation and control of the water-in-oil type nano-emulsion are realized by adopting a high-shear emulsification technology through directional assembly of a water-phase functional monomer and collaborative construction of an oil-phase stabilization dispersion system. Controllable growth of a polymer network is completed under the protection of an inert atmosphere by a'staged initiation-dynamic crosslinking 'process, and nano colloid particles with self-growth characteristics are successfully prepared in combination with a gradient demulsification and purification strategy. According to the prepared self-growing nano colloid particles, the coal gasification fine slag flotation decarburization separation efficiency is remarkably improved and the flotation reagent consumption is reduced by effectively blocking the surface pore structure of the coal gasification fine slag.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral flotation, and particularly relates to a self-growing nano-colloidal particle suitable for sealing the surface pores of coal gasification fine slag, and a preparation method and application thereof. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the overall understanding of the present invention, and it is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Coal gasification is the main trend of clean utilization of coal, but solid wastes such as fine slag generated during the gasification process seriously restrict the high-quality development of the coal industry, and its resource utilization is extremely urgent. Coal gasification fine slag is a non-uniform multiphase mixture generated by the "low-temperature eutectic" effect of organic matter and inorganic mineral components (amorphous vitreous body and amorphous porous unburned carbon) in coal. The carbon-ash separation of coal gasification fine slag is the premise of its resource utilization, and foam flotation is one of the most effective methods for efficient decarbonization.

[0004] However, when flotation is used to treat coal gasification fine slag, prominent problems such as low decarbonization efficiency and huge collector consumption are encountered. The reasons are as follows: Coal gasification is a process of converting coal into coal gas by using oxygen, steam or hydrogen as a gasifying agent under high-temperature conditions. During the coal gasification process, with the continuous volatilization of volatile components and the continuous progress of the gasification reaction, a large number of irregular pores will be formed inside and on the surface of coal particles. After the high-temperature gasification reaction, the surface of the gasification fine slag carbon particles is rich in hydrophilic sites, and at the same time, the pore structure is extremely developed, resulting in the easy loss of traditional non-polar hydrocarbon oil collectors in the pore structure and huge reagent consumption.

[0005] A variety of oilfield plugging agents are disclosed in the prior art. However, the oilfield plugging acts on rock pores / fractures with particle sizes ranging from dozens of micrometers to hundreds of millimeters, while the pore sizes of the unburned carbon on the surface of coal gasification fine slag are about 100 nm, and the required filling particle sizes of the two differ by nearly an order of magnitude; the oilfield plugging is carried out under complex conditions in the deep underground, even at high temperatures (>80 °C) and high salinity (total dissolved solids > 10 4 mg / L), while the surface pore plugging environment of coal gasification fine slag flotation is usually carried out at room temperature; the polymer gel particles used in the oilfield are used for plugging large pores and require long-term thermal stability, so the larger the self-growing expansion ratio, the better, while the surface pore plugging of coal gasification fine slag flotation needs to penetrate into nano-pores and have chemical bonding with the surface of residual carbon, so the self-growing ratio should not be too high; in addition, the fractures plugged by the oilfield are sandstone or carbonate rock, both of which are hydrophilic structures; while the pore surface of the gasification slag has a variety of hydrophilic / hydrophobic mixed complex structures such as hydroxyl groups, carboxyl groups, and polycyclic aromatic hydrocarbons.

[0006] Therefore, there is an urgent need to develop a plugging material that matches the surface pore structure of fine slag from coal gasification. Summary of the Invention

[0007] To overcome the above problems, the present invention provides self-growing nano-colloidal particles suitable for plugging the surface pores of fine slag from coal gasification, a preparation method thereof, and an application thereof. The self-growing nano-colloidal particles prepared by the present invention can be directed into the surface pore structure of fine slag from coal gasification, play a role in self-growing and efficiently plugging pores, and solve the problems of huge consumption of chemical agents and the efficiency of carbon-ash separation caused by the developed pore structure on the surface of fine slag from coal gasification.

[0008] In the first aspect of the present invention, there is provided a self-growing nano-colloidal particle suitable for plugging the surface pores of fine slag from coal gasification, which is composed of the following raw materials in weight percentages:

[0009] Functional polymerizable monomers and cross-linking polymerizable monomer agents 15-35%, surfactant 1-10%, initiator 0.01-0.5%, white oil 50-75%, and the rest is distilled water. The functional polymerizable monomers and cross-linking polymerizable monomer agents include functional polymerizable monomers and cross-linking polymerizable monomers.

[0010] In one or more embodiments, the functional polymerizable monomer is one or more of acrylic acid, acrylamide, cetyl dimethyl allyl ammonium chloride, polyethylene glycol diacrylate (PEGDA), N-vinyl pyrrolidone, octadecyl acrylate, 2-acrylamide-2-methylpropanesulfonic acid, and pentaerythritol tetraacrylate;

[0011] In one or more embodiments, the cross-linking polymerizable monomer is one or more of N,N'-methylenebisacrylamide (MBA) or polyethylene glycol (PEG-200);

[0012] In one or more embodiments, the mass ratio range of the functional polymerizable monomer to the cross-linking polymerizable monomer is 200-500:1.

[0013] In one or more embodiments, the surfactant is one or more of non-ionic surfactants and anionic surfactants;

[0014] Preferably, the non-ionic surfactant is selected from sorbitan fatty acid esters and polysorbates, preferably one or more of Span80, Span60, Tween60, or Tween80; the anionic surfactant includes sodium lignosulfonate or sodium alkyl alcohol polyoxyethylene ether carboxylate, etc.

[0015] In one or more embodiments, the initiator is one or several of inorganic initiators and organic initiators;

[0016] Preferably, the inorganic initiator includes one or more of ammonium persulfate, potassium persulfate, and sodium bisulfite; the organic initiator includes one or more of azobisisobutyronitrile and benzoyl peroxide.

[0017] In a second aspect of the present invention, there is provided a method for preparing the above self-growing nano-colloidal particles, comprising the following steps:

[0018] Step 1: Disperse the surfactant in white oil, heat and stir to obtain an oil-phase solution.

[0019] Step 2: Weigh the functional polymerizable monomer respectively, add it to a container filled with water while stirring, and stir until the solution becomes clear; then add the crosslinking polymerizable monomer to the above solution and stir until completely dissolved to prepare a uniformly dispersed aqueous solution.

[0020] Step 3: Slowly and uniformly add the aqueous solution to the oil-phase solution, use an emulsifier to shear and stir to form a mixture, place it in a container, heat and while introducing nitrogen for protection, add the initiator and stir in a magnetic stirrer to carry out a polymerization reaction.

[0021] Step 4: After the polymerization reaction is completed, demulsification occurs. Wash with a solvent, then centrifuge and dry to obtain the target self-growing nano-colloidal particles.

[0022] In one or more embodiments, in Step 1, the dispersion temperature of the surfactant is 45 - 60 °C, preferably 50 °C.

[0023] In one or more embodiments, the first stirring speed is 800 - 1000 r / min, and the stirring time is 30 - 40 min.

[0024] In one or more embodiments, the second stirring speed is 12000 - 15000 r / min, and the stirring time is 15 - 20 min.

[0025] In one or more embodiments, in order to make the initiator reach the optimal thermal decomposition activity range and prevent demulsification, the reaction temperature is controlled at 65 - 70 °C and the stirring rate under nitrogen protection is 300 - 400 r / min.

[0026] In one or more embodiments, the reaction time is 6 - 8 h, preferably 7 h.

[0027] In one or more embodiments, ethanol is selected for washing and the volume ratio to the product is between 1:2 and 1:4, preferably 1:3. The centrifugation speed is 8000 - 10000 r / min, preferably 9000 r / min. Washing and centrifugation can ensure that the nanoparticles are fully washed and effectively sedimented.

[0028] In one or more embodiments, the drying temperature is 45-55 °C, preferably 50 °C, to avoid particle sintering and agglomeration caused by high temperature; the drying time is 24-48 h until the humidity ≤ 5%.

[0029] In one or more embodiments, the particle size of the self-growing nano-colloidal particles is 20-200 nm.

[0030] In the third aspect of the present invention, there is provided the use of the above self-growing nano-colloidal particles in the flotation decarbonization process of coal gasification fine slag, including:

[0031] Adjust the concentration of the coal gasification fine slag flotation, then add the above self-growing nano-colloidal particles. After mixing evenly with the pulp, add a collector and a foaming agent. After stirring and mixing evenly, carry out air flotation.

[0032] In one or more embodiments, the concentration of the coal gasification fine slag pulp is 80-90 g / L, preferably 80 g / L.

[0033] In one or more embodiments, the addition amount of the self-growing nano-colloidal particles for coal gasification fine slag flotation with surface pore blockage is 0.8-1.2 kg per ton of dry coal gasification fine slag, preferably 1.0 kg.

[0034] In one or more embodiments, the collector is kerosene, and the dosage is 8000 grams per ton of flotation dry coal; the pulp is adjusted for 2 min after the collector is added.

[0035] In one or more embodiments, the foaming agent is MIBC, and the dosage is 5000 grams per ton of flotation dry coal; the pulp is adjusted for 30 s after the foaming agent is added, and then air flotation is carried out.

[0036] In one or more embodiments, the air inflow rate is 0.15 m 3 / h, the stirring speed is 1850 r / min, and the flotation time is about 3 min.

[0037] In the present invention, through the synergistic construction of the aqueous phase functional monomer directed assembly and the oil phase stabilization and dispersion system, the high-shear emulsification technology is used to achieve the precise regulation of the water-in-oil nanoemulsion. The unique "initiation (action of initiator)-crosslinking (action of crosslinking agent)" process completes the controllable growth of the polymer network under the protection of an inert atmosphere. Combining the gradient demulsification and purification strategy, nano-colloidal particles with self-growing characteristics are successfully prepared.

[0038] The beneficial effects of the present invention are as follows:

[0039] (1) Compared with traditional non-polar hydrocarbon oil collectors, the self-growing nano-colloidal particles prepared in the present invention can significantly improve the flotation decarbonization efficiency of coal gasification fine slag and reduce the consumption of flotation reagents by effectively plugging the pore structures on the surface of coal gasification fine slag. Analyzing its principle: The COOH, OH, and NH carried on the surface of the self-growing nano-colloidal particles 2 groups can have "hydrogen bond" interactions with the unburned carbon surface of coal gasification fine slag, forming multi-point anchoring and bionic adaptation of pore profiles, and then spontaneously entering the complex pores and crack structures of the unburned carbon on the surface of gasification fine slag under the action of pulp stirring, resulting in a pore-sealing effect; at the same time, through the self-growing characteristic of water absorption and swelling, the hierarchical pore structures such as mesopores and micropores on the coal surface are efficiently plugged, significantly reducing the specific surface area of coal gasification fine slag, realizing the efficient adhesion of the collector to coal particles, and thus greatly reducing the dosage of the collector and improving the flotation carbon-ash separation efficiency.

[0040] (2) The self-growing nano-colloidal particles provided by the present invention have structural stability (storage period ≥ 90 days) and resistance to environmental (high temperature, high salt, acid-base, etc.) disturbances based on the functional monomer self-assembly and cross-linking density regulation technology. In industrial application scenarios, the nano-colloidal particles can withstand extreme working conditions such as high-shear pulp mixing (>3000 r / min) and pulp dilution (solid-liquid ratio 1:10 - 1:50) through surface steric hindrance effects and dynamic viscoelastic responses, maintaining the integrity of the nano-colloidal structure (particle size volatility < 8%), and overcoming the problem of performance attenuation caused by mechanochemical degradation of traditional reagents.

[0041] (3) The self-growing nano-colloidal particles in the present invention can achieve precise customization of particle size distribution, surface group content, and adhesion kinetics by adjusting the proportion of functional monomers and the spatial arrangement of functional groups. This characteristic enables it to form an "anchoring-spreading" dual-mode adsorption layer through adaptive interface reconstruction, significantly broadening the applicable boundary for complex coal quality systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0043] Figure 1 It is a freeze-dried scanning electron microscope picture of the self-growing nano-gel particles prepared in Example 1.

[0044] Figure 2 It is a macroscopic morphology photo of the self-growing nano-gel particles prepared in Example 1.

[0045] Figure 3 It is a microscopic SEM picture and EDS element map of the coal gasification fine slag sample used in the experimental example. DETAILED DESCRIPTION OF THE INVENTION

[0046] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0047] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0048] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0049] The present invention provides a plugging material that matches the surface pore structure of gasification fine slag, and the matching mechanism includes three levels: molecular groups, pore size, and self-growth.

[0050] Molecular groups: The surface of gasification fine slag is usually rich in hydroxyl groups and oxygen-containing functional groups (such as carbonyl groups). The carboxyl group in acrylic acid matches the hydroxyl group on the surface of the fine slag to form hydrogen bonds. The C16 alkyl chain in cetyl dimethyl allyl ammonium chloride is embedded into the polycyclic aromatic hydrocarbon gaps in the pores of the fine slag through van der Waals forces to form a hydrophobic barrier.

[0051] Pore size: The prepared nano-colloidal particles have a size of 20 - 200 nm and can effectively enter the different pore (50 - 500 nm) structures on the surface of coal gasification fine slag to form a size match.

[0052] Self-growth: By adjusting the contents of hydrophilic monomers such as acrylic acid and acrylamide, hydrophobic monomers such as cetyl dimethyl allyl ammonium chloride, and cross-linking agents such as N,N'-methylenebisacrylamide in the nano-colloidal particles, the water absorption and swelling characteristics of the nano-colloidal particles can be precisely regulated to achieve the precise matching of the nano-colloidal particles with the surface pores of coal gasification fine slag after self-growth, forming a self-growth matching. Among them, the cross-linking agent (MBA) covalently cross-links between polymer chains through bisacrylamide groups to limit the maximum stretching length of the polymer chains. At the same time, the C16 alkyl chain in cetyl dimethyl allyl ammonium chloride self-assembles through hydrophobic interactions to form a hydrophobic core, and the low-polarity environment inside it inhibits the penetration of water molecules. The two work together to suppress the self-growth multiple within 2 - 5 times.

[0053] Based on the above three aspects, the present invention has the effect of generating directional and efficient pore blocking during the flotation carbon-ash separation process of gasification fine slag, effectively regulating the osmotic potential of the coal quality interface and inhibiting the ineffective penetration behavior of the reagent driven by capillary force, thereby significantly reducing the dosage of non-polar hydrocarbon oil collector while improving the carbon-ash separation efficiency.

[0054] Example 1

[0055] A preparation method of self-growing nano-colloidal particles suitable for blocking the surface pores of gasification fine slag

[0056] (1) Raw materials: 17.465 g of acrylic acid monomer; 13.972 g of acrylamide monomer; 3.493 g of cetyl dimethyl allyl ammonium chloride monomer; 0.07 g of crosslinking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The crosslinking agent is selected as N,N-methylenebisacrylamide; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0057] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them to a beaker containing white oil in sequence. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution; Weigh acrylic acid, acrylamide, and cetyl dimethyl allyl ammonium chloride according to the above contents, and add them to a beaker containing distilled water while stirring. Stir until the solution becomes clear; Then add N,N-methylenebisacrylamide to the above solution and stir until completely dissolved to prepare a uniformly dispersed aqueous solution. Then slowly and evenly add the aqueous solution to the oil-phase solution, use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, and while heating in a water bath at a constant temperature of 50 °C and under nitrogen protection, add ammonium persulfate solution and stir with a magnetic stirrer at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product, then perform centrifugation at 9000 r / min, and place it in a constant temperature drying oven at 50 °C for 48 h and then take it out to obtain the target self-growing nano-colloidal particles.

[0058] Example 2

[0059] A preparation method of self-growing nano-colloidal particles suitable for blocking the surface pores of gasification fine slag, which is different from Example 1 in that the dosages of each raw material are changed.

[0060] (1) Raw materials: 12.458 g of acrylic acid monomer; 9.967 g of acrylamide monomer; 2.495 g of cetyl dimethyl allyl ammonium chloride monomer; 0.08 g of crosslinking agent; 6.00 g of surfactant; 0.26 g of initiator; 64.24 g of white oil; 4.5 g of distilled water. The crosslinking agent is selected as N,N-methylenebisacrylamide; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0061] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them successively into a beaker containing white oil. Use a magnetic stirrer to stir at 900 r / min for 35 min while heating in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution; Weigh acrylic acid, acrylamide, and cetyl dimethyl allyl ammonium chloride according to the above contents, and add them to a beaker containing distilled water while stirring, and stir until the solution becomes clear; Then add N,N-methylenebisacrylamide to the above solution and stir until completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and uniformly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixed solution. Place it in a beaker, heat in a water bath at a constant temperature of 50 °C while introducing nitrogen protection, add ammonium persulfate solution, and then use a magnetic stirrer to stir at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product, and then perform centrifugation at 9000 r / min. Place the precipitate in a constant temperature drying oven at 50 °C for 48 h and then take it out to obtain the target self-growing nano-colloidal particles.

[0062] Example 3

[0063] A preparation method of self-growing nano-colloidal particles suitable for plugging the surface pores of fine slag from coal gasification, which is different from Example 1 in that the dosages of each raw material are changed.

[0064] (1) Raw materials: 7.463 g of acrylic acid monomer; 5.970 g of acrylamide monomer; 1.492 g of cetyl dimethyl allyl ammonium chloride monomer; 0.075 g of crosslinking agent; 1.00 g of surfactant; 0.01 g of initiator; 75 g of white oil; 8.99 g of distilled water. The crosslinking agent is selected as N,N-methylenebisacrylamide; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0065] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them to a beaker containing white oil in sequence. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat them in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution; Weigh acrylic acid, acrylamide, and cetyl dimethyl allyl ammonium chloride according to the above contents, and add them to a beaker containing distilled water while stirring. Stir until the solution becomes clear; Then add N,N'-methylenebisacrylamide to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, and while heating in a water bath at a constant temperature of 50 °C and passing nitrogen for protection, add ammonium persulfate solution and then stir with a magnetic stirrer at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product, and then perform centrifugation at 9000 r / min. Place it in a constant-temperature drying oven at 50 °C for 48 h and then take it out to obtain the target self-growing nano-colloidal particles.

[0066] Example 4

[0067] A preparation method of self-growing nano-colloidal particles suitable for plugging the surface pores of fine slag from coal gasification. Different from Example 1, the cross-linking agent is changed to polyethylene glycol.

[0068] (1) Raw materials: 17.465 g of acrylic acid monomer; 13.972 g of acrylamide monomer; 3.493 g of cetyl dimethyl allyl ammonium chloride monomer; 0.07 g of cross-linking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The cross-linking agent is selected as polyethylene glycol; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0069] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them successively to a beaker containing white oil. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat them in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution. Weigh acrylic acid, acrylamide, and cetyl dimethyl allyl ammonium chloride according to the above contents, and add them to a beaker containing distilled water while stirring until the solution becomes clear. Then add polyethylene glycol to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, heat it in a water bath at a constant temperature of 50 °C while introducing nitrogen protection, add ammonium persulfate solution, and then use a magnetic stirrer to stir at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product, then perform centrifugation at 9000 r / min, place it in a constant-temperature drying oven at 50 °C for 48 h, and then take it out to obtain the target self-growing nano-colloidal particles.

[0070] Example 5

[0071] A preparation method of self-growing nano-colloidal particles suitable for sealing the surface pores of fine slag in coal gasification. Different from Example 1, the surfactants are changed to Span60 and Tween60, and the initiators are changed to potassium persulfate and sodium bisulfite.

[0072] (1) Raw materials: 17.465 g of acrylic acid monomer; 13.972 g of acrylamide monomer; 3.493 g of cetyl dimethyl allyl ammonium chloride monomer; 0.07 g of cross-linking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The cross-linking agent is selected as N,N-methylenebisacrylamide; the surfactant is selected as Span60 and Tween60 (mass ratio 3:1); the initiator is selected as potassium persulfate and sodium bisulfite (mass ratio 1:1).

[0073] (2) Preparation method: Weigh Span60 and Tween60 according to the above contents and add them successively into a beaker containing white oil. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution. Weigh acrylic acid, acrylamide, and cetyl dimethyl allyl ammonium chloride according to the above contents, and add them successively to a beaker containing distilled water while stirring until the solution becomes clear. Then add N,N'-methylenebisacrylamide to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, heat in a water bath at a constant temperature of 50 °C while introducing nitrogen protection, add a mixed solution of potassium persulfate and sodium bisulfite, and then use a magnetic stirrer to stir at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product, then perform centrifugation at 9000 r / min, place it in a constant-temperature drying oven at 50 °C for 48 h, and then take it out to obtain the target self-growing nano-colloidal particles.

[0074] Example 6

[0075] A preparation method of self-growing nano-colloidal particles suitable for sealing the surface pores of fine slag from coal gasification. Different from Example 1, the surfactants are changed to Span80 and sodium lignosulfonate, and the initiator is changed to azobisisobutyronitrile.

[0076] (1) Raw materials: 17.465 g of acrylic acid monomer; 13.972 g of acrylamide monomer; 3.493 g of cetyl dimethyl allyl ammonium chloride monomer; 0.07 g of cross-linking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The cross-linking agent is selected as N,N'-methylenebisacrylamide; the surfactant is selected as Span80 and sodium lignosulfonate (mass ratio 3:1); the initiator is selected as azobisisobutyronitrile.

[0077] (2) Preparation method: Weigh Span80 and sodium lignosulfonate according to the above contents and add them successively into a beaker containing white oil. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat them in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution. Weigh acrylic acid, acrylamide, and cetyl dimethyl allyl ammonium chloride according to the above contents, and add them successively to a beaker containing distilled water while stirring until the solution becomes clear. Then add N,N'-methylenebisacrylamide to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, heat it in a water bath at a constant temperature of 50 °C while introducing nitrogen protection, add azobisisobutyronitrile solution, and then use a magnetic stirrer to stir at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product, then perform centrifugation at 9000 r / min, place it in a constant-temperature drying oven at 50 °C for 48 h, and then take it out to obtain the target self-growing nano-colloidal particles.

[0078] Example 7

[0079] A preparation method of self-growing nano-colloidal particles suitable for plugging the surface pores of fine slag from coal gasification. Different from Example 1, the surfactants are changed to Span80 and sodium alkyl polyoxyethylene ether carboxylate, and the initiator is changed to benzoyl peroxide.

[0080] (1) Raw materials: 17.465 g of acrylic acid monomer; 13.972 g of acrylamide monomer; 3.493 g of cetyl dimethyl allyl ammonium chloride monomer; 0.07 g of crosslinking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The crosslinking agent is selected as N,N'-methylenebisacrylamide; the surfactant is selected as Span80 and sodium alkyl polyoxyethylene ether carboxylate (mass ratio 3:1); the initiator is selected as benzoyl peroxide.

[0081] (2) Preparation method: Weigh Span80 and sodium alkyl alcohol polyoxyethylene ether carboxylate according to the above contents and add them to a beaker containing white oil in sequence. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution; Weigh acrylic acid, acrylamide, and cetyl dimethyl allyl ammonium chloride according to the above contents and add them to a beaker containing distilled water while stirring. Stir until the solution becomes clear; Then add N,N-methylenebisacrylamide to the above solution and stir until completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, heat in a water bath at a constant temperature of 50 °C while introducing nitrogen protection, add benzoyl peroxide solution, and then use a magnetic stirrer to stir at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product. Then, perform centrifugation at 9000 r / min, place it in a constant-temperature drying oven at 50 °C for 48 h, and then take it out to obtain the target self-growing nano-colloidal particles.

[0082] Example 8

[0083] A preparation method of self-growing nano-colloidal particles suitable for plugging the surface pores of fine slag in coal gasification. Different from Example 1, the functional monomer cetyl dimethyl allyl ammonium chloride is changed to polyethylene glycol diacrylate.

[0084] (1) Raw materials: 17.465 g of acrylic acid monomer; 13.972 g of acrylamide monomer; 3.493 g of polyethylene glycol diacrylate monomer; 0.07 g of cross-linking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The cross-linking agent is selected as N,N-methylenebisacrylamide; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0085] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them successively into a beaker containing white oil. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution. Weigh acrylic acid, acrylamide, and polyethylene glycol diacrylate according to the above contents, and add them successively to a beaker containing distilled water while stirring until the solution becomes clear. Then add N,N-methylenebisacrylamide to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, heat in a water bath at a constant temperature of 50 °C while introducing nitrogen protection, add ammonium persulfate solution, and then use a magnetic stirrer to stir at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product. Then, after centrifugation at 9000 r / min, place it in a constant-temperature drying oven at 50 °C for 48 h and then take it out to obtain the target self-growing nano-colloidal particles.

[0086] Example 9

[0087] A preparation method of self-growing nano-colloidal particles suitable for plugging the surface pores of fine slag from coal gasification. Different from Example 1, the functional monomer cetyl dimethyl allyl ammonium chloride is changed to N-vinyl pyrrolidone.

[0088] (1) Raw materials: 17.465 g of acrylic acid monomer; 13.972 g of acrylamide monomer; 3.493 g of N-vinyl pyrrolidone monomer; 0.07 g of crosslinking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The crosslinking agent is selected as N,N-methylenebisacrylamide; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0089] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them successively into a beaker containing white oil. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat them in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution. Weigh acrylic acid, acrylamide, and poly(N-vinylpyrrolidone) according to the above contents, and add them successively into a beaker containing distilled water while stirring until the solution becomes clear. Then add N,N'-methylenebisacrylamide to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, and while heating in a water bath at a constant temperature of 50 °C and passing nitrogen for protection, add ammonium persulfate solution and then stir with a magnetic stirrer at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product. Then, after centrifugation at 9000 r / min, place it in a constant-temperature drying oven at 50 °C for 48 h and then take it out to obtain the target self-growing nano-colloidal particles.

[0090] Example 10

[0091] A preparation method of self-growing nano-colloidal particles suitable for plugging the surface pores of fine slag in coal gasification. Different from Example 1, the functional monomer cetyl dimethyl allyl ammonium chloride is changed to octadecyl acrylate.

[0092] (1) Raw materials: 17.465 g of acrylic acid monomer; 13.972 g of acrylamide monomer; 3.493 g of octadecyl acrylate monomer; 0.07 g of cross-linking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The cross-linking agent is selected as N,N'-methylenebisacrylamide; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0093] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them successively into a beaker containing white oil. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat them in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution. Weigh acrylic acid, acrylamide, and octadecyl acrylate according to the above contents, and add them successively to a beaker containing distilled water while stirring until the solution becomes clear. Then add N,N-methylenebisacrylamide to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed aqueous-phase solution. Then slowly and evenly add the aqueous-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, heat it in a water bath at a constant temperature of 50 °C while introducing nitrogen protection, add ammonium persulfate solution, and then use a magnetic stirrer to stir at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product, then perform centrifugation at 9000 r / min, place it in a constant-temperature drying oven at 50 °C for 48 h, and then take it out to obtain the target self-growing nano-colloidal particles.

[0094] Example 11

[0095] A preparation method of self-growing nano-colloidal particles suitable for plugging the surface pores of fine slag in coal gasification. Different from Example 1, the functional monomer cetyl dimethyl allyl ammonium chloride is changed to 2-acrylamido-2-methylpropanesulfonic acid.

[0096] (1) Raw materials: 17.465 g of acrylic acid monomer; 13.972 g of acrylamide monomer; 3.493 g of 2-acrylamido-2-methylpropanesulfonic acid; 0.07 g of cross-linking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The cross-linking agent is selected as N,N-methylenebisacrylamide; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0097] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them successively into a beaker containing white oil. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat them in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution. Weigh acrylic acid, acrylamide, and 2-acrylamido-2-methylpropanesulfonic acid according to the above contents, and add them successively into a beaker containing distilled water while stirring until the solution becomes clear. Then add N,N'-methylenebisacrylamide to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, and while heating in a water bath at a constant temperature of 50 °C and under nitrogen protection, add ammonium persulfate solution and then stir with a magnetic stirrer at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product, and then perform centrifugation at 9000 r / min. Place it in a constant-temperature drying oven at 50 °C for 48 h and then take it out to obtain the target self-growing nano-colloidal particles.

[0098] Example 12

[0099] A preparation method of self-growing nano-colloidal particles suitable for plugging the surface pores of fine slag from coal gasification. Different from Example 1, the functional monomer cetyl dimethyl allyl ammonium chloride is changed to pentaerythritol tetraacrylate.

[0100] (1) Raw materials: 17.465 g of acrylic acid monomer; 13.972 g of acrylamide monomer; 3.493 g of pentaerythritol tetraacrylate; 0.07 g of cross-linking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The cross-linking agent is selected as N,N'-methylenebisacrylamide; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0101] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them successively into a beaker containing white oil. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat them in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution. Weigh acrylic acid, acrylamide, and pentaerythritol tetraacrylate according to the above contents, and add them successively into a beaker containing distilled water while stirring until the solution becomes clear. Then add N,N-methylenebisacrylamide to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13,000 r / min for 15 min to form a mixture. Place it in a beaker, heat it in a water bath at a constant temperature of 50 °C while introducing nitrogen protection, add ammonium persulfate solution, and then use a magnetic stirrer to stir at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product, then perform centrifugation at 9000 r / min, place it in a constant-temperature drying oven at 50 °C for 48 h, and then take it out to obtain the target self-growing nano-colloidal particles.

[0102] Comparative Example 1

[0103] A preparation method of self-growing nano-colloidal particles suitable for plugging the surface pores of fine slag from coal gasification, which is different from Example 1 in that it does not contain the functional monomer cetyl dimethyl allyl ammonium chloride.

[0104] (1) Raw materials: 17.465 g of acrylic acid monomer; 17.465 g of acrylamide monomer; 0.07 g of cross-linking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The cross-linking agent is selected as N,N-methylenebisacrylamide; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0105] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them successively into a beaker containing white oil. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat them in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution. Weigh acrylic acid and acrylamide respectively according to the above contents, and add them successively into a beaker containing distilled water while stirring until the solution becomes clear. Then add N,N-methylenebisacrylamide to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, heat it in a water bath at a constant temperature of 50 °C while introducing nitrogen protection, add ammonium persulfate solution, and then use a magnetic stirrer to stir at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product. Then, centrifuge it at 9000 r / min, place it in a constant-temperature drying oven at 50 °C for 48 h, and then take it out to obtain the target self-growing nano-colloidal particles.

[0106] Comparative Example 2

[0107] A preparation method of self-growing nano-colloidal particles suitable for sealing the surface pores of fine slag in coal gasification. Different from Example 1, the total amount of functional polymerization monomers and cross-linked polymerization monomer agents is reduced to 13%.

[0108] (1) Raw materials: 6.50 g of acrylic acid monomer; 5.50 g of acrylamide monomer; 1.00 g of cetyl dimethyl allyl ammonium chloride monomer; 0.07 g of cross-linking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The cross-linking agent is selected as N,N-methylenebisacrylamide; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0109] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them successively into a beaker containing white oil. Use a magnetic stirrer to stir at 900 r / min for 35 min to mix the three evenly. While stirring, heat them in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution. Weigh acrylic acid, acrylamide, and cetyl dimethyl allyl ammonium chloride according to the above contents, and add them successively into a beaker containing distilled water while stirring until the solution becomes clear. Then add N,N'-methylenebisacrylamide to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13,000 r / min for 15 min to form a mixture. Place it in a beaker, heat it in a water bath at a constant temperature of 50 °C while introducing nitrogen protection, add ammonium persulfate solution, and then use a magnetic stirrer to stir at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product, and then perform centrifugation at 9,000 r / min. Place it in a constant-temperature drying oven at 50 °C for 48 h and then take it out to obtain the target self-growing nano-colloidal particles.

[0110] It was found that when the total amount of the functional polymerization monomer and the cross-linked polymerization monomer type agents was relatively low, they quickly dissolved in water and could not maintain the state of nano-particles. Analyzing the reason, it may be that at this addition amount, the polymerization reaction rate and the cross-linking degree decreased significantly, resulting in the difficulty of the prepared colloidal particles to form a three-dimensional network structure and the gel strength being weak.

[0111] Comparative Example 3

[0112] A preparation method of self-growing nano-colloidal particles applicable to the surface pore plugging of fine slag in coal gasification. Different from Example 1, the total amount of the functional polymerization monomer and the cross-linked polymerization monomer type agents was reduced to 40%.

[0113] (1) Raw materials: 20.465 g of acrylic acid monomer; 15.972 g of acrylamide monomer; 3.493 g of cetyl dimethyl allyl ammonium chloride monomer; 0.07 g of cross-linking agent; 10.00 g of surfactant; 0.5 g of initiator; 50 g of white oil; 4.5 g of distilled water. The cross-linking agent is selected as N,N'-methylenebisacrylamide; the surfactant is selected as Span80 and Tween60 (mass ratio 3:1); the initiator is selected as ammonium persulfate.

[0114] (2) Preparation method: Weigh Span80 and Tween60 according to the above contents and add them successively into a beaker containing white oil. Use a magnetic stirrer to stir the three at 900 r / min for 35 min to mix them evenly. While stirring, heat them in a water bath at a constant temperature of 50 °C to prepare a uniformly dispersed oil-phase solution. Weigh acrylic acid, acrylamide, and cetyl dimethyl allyl ammonium chloride according to the above contents, and while stirring, add them successively into a beaker containing distilled water and stir until the solution becomes clear. Then add N,N'-methylenebisacrylamide to the above solution and stir until it is completely dissolved to prepare a uniformly dispersed water-phase solution. Then slowly and evenly add the water-phase solution to the oil-phase solution, and use a high-shear emulsifier to stir at 13000 r / min for 15 min to form a mixture. Place it in a beaker, heat it in a water bath at a constant temperature of 50 °C, and while introducing nitrogen protection, add ammonium persulfate solution and then stir with a magnetic stirrer at 350 r / min for 7 h. After the polymerization reaction is completed, demulsification occurs. Wash it 3 times with ethanol with a volume ratio of 1:3 to the product, and then perform centrifugation at 9000 r / min. Take it out after placing it in a constant-temperature drying oven at 50 °C for 48 h to obtain the target self-growing nano-colloidal particles.

[0115] It was found that when the total amount of functional polymerizable monomers and crosslinked polymerizable monomer agents was relatively high, the polymerization reaction rate and crosslinking degree were significantly improved, but the problem of explosive polymerization occurred, resulting in too high molecular weight of the prepared colloidal particles, and the generation of some bubbles and cracks. Under the condition of a flotation stirring and mixing speed of 1850 r / min, the nano-colloidal particles had the problem of brittle fracture and could not effectively enter the pores on the surface of the gasification fine slag for plugging. Experimental Example 1

[0116] (1) Microscopic morphology characterization of nano-colloidal particles

[0117] Taking the self-growing nano-colloidal particles prepared in Example 1 as an example, test their performance. Specifically:

[0118] As Figure 1 shown are the freeze-dried scanning electron microscope pictures of the prepared self-growing nano-colloidal particles. It can be seen from Figure 1 that the particle size of the self-growing nano-colloidal particles shows polydispersity, indicating that their shapes and sizes are different, and the average particle size is about 200 nm.

[0119] (2) Macroscopic morphology characterization of nano-colloidal particles

[0120] Taking the self-growing nano-colloidal particles prepared in Example 1 as an example, test their performance. Specifically:

[0121] As Figure 2 shown are the macroscopic morphology photos of the prepared self-growing nano-colloidal particles. It can be seen from Figure 2 that the self-growing nano-colloidal particles are in the shape of white powder particles.

[0122] (3) Study on the Structural Stability of Nano Colloidal Particles

[0123] Taking the self - growing nano colloidal particles prepared in Example 1 as an example, their properties were tested. Specifically:

[0124] The particle size change of the self - growing nano colloidal particles after being stored at room temperature for 90 days was studied by a nano particle size analyzer. It was found that the particle size hardly changed, indicating its excellent structural stability (storage period ≥ 90 days). In addition, the shear stability of the self - growing nano colloidal particles was studied using a high - shear equipment. It was found that in industrial application scenarios, through the surface steric effect and dynamic viscoelastic response, the nano colloidal particles could withstand extreme working conditions such as high - shear sizing (> 3000 r / min) and pulp dilution (solid - liquid ratio 1:10 - 1:50), and maintain the integrity of the nano colloidal structure (particle size volatility < 8%).

[0125] Experimental Example 2

[0126] (1) Flotation Test

[0127] The nano colloidal particles prepared by the present invention were used for the flotation of coal gasification fine slag, including the following steps:

[0128] The concentration of the coal slurry to be floated was adjusted to 80 g / L. After adding a collector and stirring evenly, wait for 2 min, then add a frother and stir evenly, and then wait for 30 s and carry out air - flotation. Among them, the air - inflow rate was 0.15 m 3 / h, the stirring speed was 1850 r / min, and the flotation time was about 3 min. The addition amount of the nano colloidal particles prepared in Examples 1 - 7 was 1 kg per ton of dry coal gasification fine slag. Kerosene, a conventional flotation reagent, was selected in Examples 1 - 7, with a dosage of 8000 g / t, and the frother was fixed as MIBC, with a dosage of 5000 g / t.

[0129] In Comparative Example 4, the self - growing nano colloidal particles prepared above were not added, and the flotation kinetics test of coal gasification fine slag was directly carried out.

[0130] It should be noted that the coal sample used in the test was coal gasification fine slag, and the feed ash content was 63.75%. As Figure 3 shown were the scanning electron microscope (SEM) pictures and energy - dispersive spectroscopy (EDS) pictures of the coal gasification fine slag. From Figure 3It can be seen that since the gasification slag is the residue of coal gasification at high temperatures (1400 - 1600 °C), the surface of the fine coal gasification slag has a rich pore structure and a large number of regular spherical glass bead materials; further analysis by EDS reveals that the porous material is mainly composed of C (organic unburned carbon), while the spherical glass beads are mainly composed of Si and Al (inorganic aluminum silicate). After the original fine coal gasification slag is crushed, screened, blended, and reduced, an analytical coal sample with a particle size less than 0.5 mm is prepared in accordance with the "Preparation Method of Coal Samples" (GB474 - 1984). The test method is carried out for performance detection in accordance with the "Experimental Method for Unit Flotation in Coal Preparation Laboratories" (GB4758 - 1984). The final test results are shown in Table 1:

[0131] Table 1 Test Results of Flotation Decarbonization Separation of Coal Gasification Fine Slag

[0132]

[0133]

[0134] (2) Particle Size Test of Nano Colloidal Particles:

[0135] Using a nano particle size analyzer (Nano ZSE, Malvern Panalytical, UK), the particle sizes of the nano colloidal particles synthesized in Example 1, Examples 8 - 12, and Comparative Example 1 are tested; in addition, the particle size distribution of the nano colloidal particles after water absorption and swelling is further tested to examine their self - growth characteristics. The experimental steps include: diluting the synthesized nano colloidal particles with ultrapure water to 0.1 - 1 mg / mL, filtering through 0.45 μm and 0.22 μm filter membranes in sequence to remove large - particle aggregates, and equilibrating in a 25 °C constant - temperature water bath for 30 minutes to eliminate thermal disturbances. The particle size distribution is measured using a dynamic light scattering instrument at 25 °C and a scattering angle of 90°, setting the laser power at 50% and the acquisition time at 60 seconds per measurement, and simultaneously deducting the background interference with a blank solvent. The specific test results are shown in Table 2.

[0136] Table 2 Test Results of Particle Sizes of Nano Colloidal Particles

[0137] Test items Particle size / nm Average particle size / nm Particle size after water absorption and swelling / nm Average particle size after water absorption and swelling / nm Example 1 20～50 35 40～250 140 Example 2 80～110 95 160～550 380 Example 3 130-170 150 260～850 500 Example 4 100-140 120 200～700 480 Example 5 60～90 75 120～450 300 Example 6 40～70 55 80～350 220 Example 7 35～70 50 70～350 200 Comparative example 1 100-200 150 <![CDATA[1×10 3 ~1×10 5 > <![CDATA[1×10 4 >

[0138] Due to the influence of the functional monomer functional group type, content, and structural composition in the nano colloidal particles, the particle sizes of the products obtained in Examples 1 - 7 are slightly different, but the average particle size after water absorption and swelling does not exceed 500 nm, and the particle size distribution is below 1000 nm, which can be used for plugging the pore structure on the surface of the fine coal gasification slag. However, in Comparative Example 1, there is no functional monomer (such as cetyl dimethyl allyl ammonium chloride, etc.), and the particle size of the obtained nano colloidal particles after water absorption and swelling is too high (greater than 1000 nm), making it inapplicable for plugging the pores on the surface of the fine coal gasification slag.

[0139] (3) Testing of the surface pore structure of the gasification fine slag:

[0140] The BET specific surface area of the coal samples before and after being treated with different nano-colloidal particles was tested. The experimental steps included: adjusting the concentration of the coal slurry to be tested to 80 g / L, adding the nano-colloidal particles with the best effect (Example 1), stirring evenly with a magnetic stirrer at a stirring speed of 600 r / min for 5 min, filtering the obtained filter cake after stirring, and placing it in an oven at 30 °C for vacuum drying. The dried sample was tested by a BET specific surface area and pore size analyzer (V-Sord 2800TP, Beijing Guoyi Precision Measurement Technology Co., Ltd.). The specific test results are shown in Table 3.

[0141] Table 3 Test results of the surface pore structure of the gasification fine slag before and after the action of the best nano-colloidal particles

[0142] Test items <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Total pore volume of adsorption (cm 3 / g)]]> Average pore diameter (nm) As received 306.905 0.7187 11.516 Example 1 240.193 0.3376 4.401

[0143] The size adaptation and self-growth performance of the nano-colloidal particles provided by the present invention determine the plugging effect.

[0144] As shown in Table 2, in Example 1, nano-colloidal particles with a particle size of 20 - 50 nm (average 35 nm) were used, and the corresponding unburned carbon removal rate (Table 1) reached 92.48%, which was significantly better than that of Comparative Example 4 without nano-colloidal particles (the unburned carbon removal rate was only 60.77%). This is because the particle size of the nano-colloidal particles needs to match the surface pore size of the gasification fine slag (the average original pore diameter in Table 3 is 11.5 nm): small-sized nano-colloidal particles can penetrate into the interior of the pores, and after being treated in Example 1, the average pore diameter decreased to 4.4 nm, indicating that the nano-colloidal particles effectively filled the pore channels. In Comparative Example 1 in Table 2, the particle size of the nano-colloidal particles exceeded the surface pore size of the gasification fine slag, resulting in difficulty in entering the micropores to produce effective plugging and poor flotation decarbonization effect.

[0145] The data in Table 3 show that after being treated in Example 1, the total adsorption pore volume decreased sharply from 0.7187 cm 3 / g to 0.3376 cm 3 / g, a decrease of 53%. This unexpected reduction in pore volume indicates that the nano-colloidal particles not only fill the pores but also can self-aggregate or form chemical bonds and adsorption within the pores (small-sized nano-colloidal particles can enter the interior of the pores and spontaneously aggregate through van der Waals forces or electrostatic attraction; the negative charge on the colloid surface combines with the positive charge region of the unburned carbon through electrostatic adsorption; the carboxyl / amino functional groups form hydrogen bonds or covalent bonds with the oxygen-containing groups on the surface of the unburned carbon, promoting the agglomeration of carbon particles), forming a secondary plugging layer. This dynamic self-growth characteristic enables the nano-colloidal particles to adapt to the pore morphology, form a dense barrier, and thus improve the carbon-ash separation efficiency.

[0146] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A self-growing nano-colloidal particle suitable for plugging pores on the surface of coal gasification fine slag, characterized in that: The following raw materials are included in weight percentage: Functional polymerization monomers and cross-linking polymerization monomers 15-35%, surfactant 1-10%, initiator 0.01-0.5%, white oil 50-75%, and the rest is distilled water; The functional polymerizable monomer and cross-linking polymerizable monomer agent comprises a functional polymerizable monomer and a cross-linking polymerizable monomer.

2. The self-growing nano-colloidal particles suitable for plugging pores on the surface of coal gasification fine slag according to claim 1, characterized in that: The functional polymerizable monomer is one or more of acrylic acid, acrylamide, hexadecyl dimethyl allyl ammonium chloride, polyethylene glycol diacrylate, N-vinyl pyrrolidone, octadecyl acrylate, 2-acrylamide-2-methylpropane sulfonic acid or pentaerythritol tetraacrylate.

3. The self-growing nano-colloidal particles suitable for plugging pores on the surface of coal gasification fine slag according to claim 2, characterized in that: The cross-linking polymerization monomer is one or both of N,N-methylenebisacrylamide and polyethylene glycol.

4. The self-growing nano-colloidal particles suitable for plugging pores on the surface of coal gasification fine slag according to claim 2, characterized in that: The mass ratio of the functional polymer monomer to the cross-linking polymer monomer is in the range of 200-500:

1.

5. The self-growing nano-colloidal particles suitable for plugging pores on the surface of coal gasification fine slag according to claim 1, characterized in that: The surfactant is one or more of a nonionic surfactant or an anionic surfactant; The nonionic surfactant is selected from sorbitan fatty acid esters and polysorbates, preferably one or more of Span80, Span60, Tween60 or Tween80; The anionic surfactant is selected from sodium lignin sulfonate or sodium alkyl alcohol polyoxyethylene ether carboxylate.

6. The self-growing nano-colloidal particles suitable for plugging pores on the surface of coal gasification fine slag according to claim 1, characterized in that: The initiator is one or more of an inorganic initiator or an organic initiator; The inorganic initiator includes one or more of ammonium persulfate, potassium persulfate, and sodium bisulfite; the organic initiator includes one or more of azobisisobutyronitrile and benzoyl peroxide.

7. A method for preparing self-growing nano-colloidal particles suitable for plugging pores on the surface of coal gasification fine slag, characterized in that: The following steps are involved: Step 1, dispersing the surfactant in white oil, heating and stirring to prepare an oil phase solution; Step 2, weighing functional polymer monomers respectively, adding them into a container containing water while stirring, and stirring until the solution becomes clear; then adding cross-linking polymer monomers into the above solution, stirring until all dissolved, to prepare a uniformly dispersed aqueous solution; Step 3, slowly and evenly adding the aqueous phase solution to the oil phase solution, using an emulsifier to shear and stir to form a mixed solution, placing the mixed solution in a container, heating and introducing nitrogen protection, adding an initiator, and stirring in a magnetic stirrer to perform a polymerization reaction; Step 4: after the polymerization reaction is completed, demulsification occurs, and self-growing nano-colloidal particles are obtained after washing, centrifugation and drying.

8. The method for preparing self-growing nano-colloidal particles suitable for plugging pores on the surface of coal gasification fine slag according to claim 7, characterized in that: In step 1, the dispersion temperature of the surfactant is 45 to 60°C; In step 3, the reaction temperature is controlled at 65-70° C., and the stirring rate is 300-400 r / min under nitrogen protection; the reaction time is 6-8 h.

9. The method for preparing self-growing nano-colloidal particles suitable for plugging pores on the surface of coal gasification fine slag according to claim 7, characterized in that: The particle size of the self-growing nano-colloid particles is 20-200 nm.

10. Use of the self-growing nano-colloidal particles suitable for plugging pores on the surface of coal gasification fine slag according to any one of claims 1 to 6 in the flotation separation process of coal gasification fine slag, characterized in that: Its application methods include: The concentration of gasified fine slag flotation is adjusted, and then the self-growing nano colloidal particles according to any one of claims 1 to 6 are added, and after being evenly mixed with the ore pulp, a collector and a frother are added, and after stirring and mixing, aeration flotation is performed.

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