142results about How to "Reduce electrostatic repulsion" patented technology

The invention relates to continuous high efficiency nano spinning solution (15), a nanofiber nonwovens manufacturing method and a manufacturing device which not only has high manufacturing efficiency but form better thickness of the nanofiber nonwovens. The manufacturing device comprises a solution supply system, a solution feeding pipe (8), a connecting mechanism and a metal roller (6); a metal strainer (10) and a fiber receiving web (11) which have the same shaft with the metal roller are sequentially arranged on the outside of the metal roller (6), an unreel roller (12) and a winding roller (13) are arranged on the fiber receiving web (11), and pores (7) are cut on the hollow metal roller (6). The manufacturing method includes the steps: (1), polymer spinning solution (15) is prepared; (2), an electric field is arranged between the metal roller (6) and metal strainer (10); (3), the metal roller (6) is revolved at a certain speed; (4) a measuring pump (4) is led to the metal roller (6) for even internal inputting; (5), the nanofiber is received. The invention is good for the scale manufacturing of static spinning.

The invention provides a preparation method and application of a pH sensitive type magnetic demulsifier with surface charges and hydrophilic-hydrophobic properties controlled. Based on magnetic Fe3O4 nanoparticles, through surface modification with silicon dioxide and a grafting copolymerization reaction, surface active monomers and pH sensitive monomer copolymer chains are introduced on the surfaces of the nanoparticles, and the surface grafting structure and the pH value are further adjusted to control the surface charges and hydrophilic-hydrophobic properties of the magnetic nanoparticles. The reduction of the pH value can enhance the hydrophobic property of the magnetic nanoparticles and reduce negative charge repulsive interaction between the demulsifier and oil droplets so that the demulsifier can be absorbed onto the surfaces of the emulsified oil droplets and quickly isolate the emulsified oil droplets under the action of an external magnetic field. Recycling of the magnetic nanoparticles can be achieved, and the demulsifier is be unlikely to be affected by pollution of negative-ion surface active materials in emulsified oil wastewater. According to the magnetic demulsifier, the preparation method is simple, the recycling process is convenient and efficient, the recycling performance is excellent, and therefore the magnetic demulsifier has very board application prospects in the fields of emulsified oil wastewater treatment and oil-water separation.

The invention discloses a method for loading siRNA (small interfering Ribonucleic Acid) by using mesoporous silicon dioxide nanoparticles. In the method, the siRNA is induced into a pore cannel of the mesoporous silicon dioxide nanoparticles, so that loading of the siRNA is realized, and the loading capacity of the siRNA in the particles can be adjusted. The invention has the advantages: siRNA molecules are prevented from being separated from the pole canal under the condition of physiological environment; the surfaces of the loaded nanoparticles can be further decorated; and the method has a good application prospect.

The invention discloses a collecting agent for phosphorite reverse flotation calcite, the collecting agent is composed of the components in following mass percent: 40-80% of fatty acid polyoxyethylene ester salt, 14-50% of alkyl polyoxyethylene ether phosphate monoester salt, 5-20% of fatty alcohol polyoxyethylene ether and 1-20% of span 20. The collecting agent is suitable for phosphorite reverse flotation calcite. Compared with the fatty acid collecting agent, the collecting agent has strong collecting capability and high selectivity; compared with the alpha-amido aryl phosphoric acid collecting agent, the price is low, the dosage is little, and the material is convenient. The collecting agent overcomes the defects of processing calcite in phosphorite by conventional flotation processing method that the collecting capability is poor, the recovery rate is low and the medicine cost is high. The collecting agent has obvious superiority on indicators in beneficiation and has new breakthrough.

The invention provides a non-aqueous solvent dyeing method of a washing-free reactive dye. The non-aqueous solvent dyeing method comprises the following steps: mixing pre-treated loose fibers, yarns, fabric or clothes with an reactive dye, a micro-molecular quaternary ammonium salt and a good solvent of the reactive dye, so as to form a mixing system; raising the temperature of the mixing system; adding a bad solvent of the reactive dye into the mixing system before raising the temperature or in a temperature rising process; keeping the heat after raising the temperature to a dyeing temperature, wherein the volume ratio of the good solvent of the reactive dye and the bad solvent of the reactive dye is 1 to (3-30), the ratio of the volume of the good solvent of the reactive dye to the mass of the loose fibers, the yarns, the fabric or the clothes is (0.8-10)mL to 1g, and the mass ratio of the micro-molecular quaternary ammonium salt to the reactive dye is (0.1-0.5) to 1; and then drying and putting into a color fixation solution and carrying out color fixation treatment, wherein the color fixation solution contains a 5-100g / L color fixation agent.

The invention discloses a method for preparing a layer-layer assembling microcapsule based on interaction of subject and object. The method obtains a microcapsule having multilayer structure, which capsule wall has interaction of subject and object by the steps of: forming a multilayer film on a surface of a colloidal particle in a manner of self-assembling layer upon layer, by the interaction of subject and object of beta-cyclodextrin and dicyclopentadienyl iron in polyallylamine grafting beta--cyclodextrin and polyallylamine grafting dicyclopentadienyl iron, based on the colloidal particle as a template; and removing the colloidal particle. Attractive force of the interaction of subject and object and electrostatic repulsive force of identical electrical charges exist in the capsule wall, so that relative size of the two forces can be controlled by changing chemical environment condition of the microcapsule such as PH value, ionic strength, molecular concentration of free subject and the like, thus controllable variation of the microcapsule size can be easily achieved. The method for preparing the microcapsule of the invention has extremely abroad latent applied cost in nanometer materials, drug releasing, biosensor, etc.

The invention relates to a method for dyeing green silk fabrics by sodium copper chlorophyllin. The dyeing method is a direct dyeing method without using mordant, and the parameters of the dyeing process are as follows: the bath ratio is 1:30-50, the pH value of a dye bath is 7 to 9, the dyeing temperature is 70 to 90 DEG C, the heat-insulating dyeing time is 60 to 120min, and the weight of the sodium copper chlorophyllin accounts for 1 to 3 percent of that of the silk fabric to be dyed; NaCl additives can simultaneously be added into the dye bath, and the application amount thereof is 2-8g / L, the NaCl additives and the sodium copper chlorophyllin can be simultaneously added into the dye bath for one time or for times. The sodium copper chlorophyllin in the invention is safe and non-toxic, and is widely used in food colourants; and the green silk fabrics dyed by the sodium copper chlorophyllin are vivid and bright, and can be used in the development of high-grade pure silk underwear.

The invention discloses a novel azlactone-based polyamide membrane and a preparation method thereof, and belongs to the technical field of a nanofiltration membrane (loose reverse osmosis membranes).The azlactone-based polyamide membrane is formed by monomers containing azlactone groups and primary aliphatic monomers through interface polymerization reaction; the azlactone-based polyamide membrane shows the electric neutral state or the electropositivity state on a surface structure and has a smooth membrane surface; good anti-pollution performance and excellent interception effect on bivalent and multivalence cations are shown in aspects of performance; the CUT-OFF of the azlactone-based polyamide membrane is 300 to 600 Dalton. The azlactone-based polyamide membrane can be widely appliedto material separation processes such as water softening, dye / salt separation, and concentration and separation of amino acid polypeptide molecules with different molecular weights, and can also be used in the water treatment fields of sea water desalination, brackish water pretreatment and the like.

The invention provides an iron ion reinforced anaerobic ammonia oxidation denitrification process, which comprises the following steps of firstly adding a trace element concentration solution into waste water to be treated; then regulating the pH of the waste water to be treated; finally performing aeration to obtain treated waste water; meanwhile, adding treated sludge into an anaerobic ammonia oxidation reactor; next, introducing the treated waste water into the anaerobic ammonia oxidation reactor; meanwhile, using an adder for adding iron ions in a water inlet position of the anaerobic ammonia oxidation reactor; controlling the reaction temperature of the anaerobic ammonia oxidation reactor and the sludge concentration in the anaerobic ammonia oxidation reactor in the denitrification process, wherein the sludge retention time of the anaerobic ammonia oxidation reactor is 20 to 60d; pumping oxygen gas into the anaerobic ammonia oxidation reactor. Generally, the process design is reasonable; the anaerobic ammonia oxidation denitrification efficiency can be improved; the anaerobic ammonia oxidation denitrification enrichment culture speed is accelerated; the process stability is improved.

The invention discloses a slow breaking and quick setting cationic asphalt emulsifier, consisting of the following components: fatty acid containing 16-22 carbons, triethylene tetramine, organic solvent, antioxidant, catalyst and nonionic surfactant. In the preparation process of the slow breaking and quick setting cationic asphalt emulsifier, the asphalt emulsifier is prepared by adopting a microwave heating technology, so that the synthesis time is 2.5-3h shorter than the traditional time. When the emulsified asphalt prepared from the slow breaking and quick setting cationic asphalt emulsifier is used for a thin slurry sealing layer, the consumption is 0.8-1.2%; moreover, a pavement can be quickly set, the open traffic time can be shortened to 30-40min, and quick traffic can be realized. The asphalt content of the emulsified asphalt prepared from the slow breaking and quick setting cationic asphalt emulsifier can reach 70%. The whole synthesis process does not pollute the ambient environment.

The invention discloses chitosan / zwitter-ion and acrylic acid copolymer double network self-healing hydrogel and a preparation method thereof, and relates to the technical field of hydrogel. The hydrogel is of a double network structure, and formed by a first network and a second network in a mutually penetrating mode, the first network is a physical cross-linking network formed by chitosan and polyvalent negative ions, the second network is a copolymer network formed by a zwitter-ion monomer and an acrylic acid monomer, the first network intersperses in the second network, the chitosan and the polyvalent negative ions are selected to form the first network, the zwitter-ion monomer and the acrylic acid monomer are selected to form the second network, the double network self-healing hydrogel, obtained by the cross-linking purely physical effect, with the mutually interspersed first network and the second network makes the hydrogel have excellent mechanical performance and self-healing ability, the high relative resistance change rate is provided when deformation occurs, and the chitosan / zwitter-ion and acrylic acid copolymer double network self-healing hydrogel has broad applicationprospects in the field of soft electronics, especially as biomedical sensors.

The invention provides a hollow glass bead / titanium dioxide membrane composite material and a preparation method thereof. The composite material is of a core-shell structure; and the thickness of a titanium dioxide membrane is 0.3-0.7 microns, the titanium dioxide exists in an anatase type, and the coating quantity is 5-25 percent. The method comprises the following steps of mixing and dissolvingabsolute ethyl alcohol, tetrabutyl titanate and glacial acetic acid, and then dropwise adding a mixed aqueous solution obtained by mixing the absolute ethyl alcohol, water and a pH regulator in a tetrabutyl titanate solution to prepare a titanium dioxide sol; performing ultrasonic cleaning on a hollow glass bead to remove impurities on the surface and perform alkali activation on the surface; andadding the activated hollow glass bead in the titanium dioxide sol, and performing standing and ageing to realize uniformity and compactness of coating of the surface of the hollow glass bead. The hollow glass bead / titanium dioxide membrane composite material and the preparation method solve the problems of low coating ratio of titanium dioxide, unevenness and looseness in a coating layer, low near-infrared band reflectivity and the like.

A microemulsion detergent for resource treatment of oil-containing solid waste, and a preparation method and an application thereof are provided. The microemulsion detergent comprises the components by the mass percentage: 1.2%-4.0% of fatty alcohol polyoxyethylene ether sulfate, 2.0%-4.0% of butyl lactate, 0.5%-1.0% of amyl propionate, 0.3%-0.9% of sodium chloride, and 91.1%-96% of water. The microemulsion detergent can be mixed with the oil-containing solid waste at room temperature, can complete repair treatment and can recycle oil resources with high efficiency; cheap and easily accessible NaCl is used as an electrolyte, other components have less amount, treatment operation is simple, three-phase separation is facilitated, and subsequent treatment of sludge is facilitated; and an intermediate liquid phase namely a microemulsion phase can also continue to be recycled, so that the cost is lower.

The invention relates to a surfactant for changing surface wettability of compact sandstone as well as a preparation method and an application of the surfactant. An oil phase solution is added to a water phase solution, and a dispersed and uniform phase is realized after 1-2 h under the action of an emulsifier. An initiator is added, the mixture is stirred and heated to 60-75 DEG C and reacts at the temperature for 12-18 h, and a colorless and clear liquid, namely, a high-molecular polymer, is prepared. A fluorocarbon surfactant and a biosurfactant are added at the room temperature, the mixture is stirred continuously for 4 h, and the surfactant for changing surface wettability of the compact sandstone is obtained. By the aid of the surfactant, the oil-water interface tension can be reduced, an oil wetted surface can be changed into a water wetted surface, the adhesion of oil drops on sandstone surfaces can be reduced, the flowability of crude oil in an original stratum can be improved, and the recovery percent of low-permeability oil reservoirs can be increased.

The present invention provides aqueous chemical mechanical planarization (CMP) polishing compositions have excellent heat aging and shelf stability in the form of concentrates comprising a mixture of a compound containing two quaternary ammonium groups, such as hexabutyl C1-C8 alkanediammonium dihydroxides or salts thereof, preferably N,N,N,N′,N′,N′-hexabutyl-1,4-butanediammonium dihydroxide (HBBAH), and aminosilane group containing silica particles in the amount of from 1 to 30 wt. % or, preferably, from 15 to 22 wt. %, as solids based on the total weight of the composition, the composition having a pH ranging from 3 to 5 or, preferably, from 3.5 to 4.5 wherein the composition is stable against visible precipitation or sedimentation at a 15 wt. % solids content after heat aging at a temperature of 45° C. for at least 6 days.

The invention discloses a quaternary ammonium salt modified Pd / C electrocatalyst as well as an electrode and preparation and application thereof. The electrocatalyst comprises carbon dust and Pd nanoparticles, wherein the Pd nanoparticles are supported by the carbon dust to form a nano Pd / C composite material; and quaternary ammonium salt is adhered to the surface of the nano Pd / C composite material. The quaternary ammonium salt is adopted to modify Pd / C, by virtue of the electropositivity and the complexing effect (with pollutants) of the quaternary ammonium salt, the electrostatic repulsiveinteraction of chlorine-containing pollutants with cathode electrodes can be alleviated, adsorption of the chlorine-containing pollutants can be enhanced, and dechloridation efficiency can be improved.

The invention discloses a preparation method of antibacterial paper containing a quaternary ammonium salt antibacterial agent, and belongs to the technical field of functional packaging paper. The quaternary ammonium salt antibacterial agent is a quaternization styrene-maleic anhydride copolymer. By adopting the two modes of surface coating and wet end addition, the quaternary ammonium salt antibacterial agent is added into the paper, and the most suitable quaternary ammonium salt antibacterial agent concentration, addition method, temperature and pressure are provided. In this way, the antibacterial paper is environmentally friendly and has the good and lasting antibacterial effect.

The invention discloses a high-stability organic silicon emulsion, and a preparation method and application thereof. The organic silicon emulsion is prepared from the following raw materials in parts by weight: 10-60 parts of silane monomer, 0.03-6 parts of emulsifier, 0.03-1.2 parts of initiator and 34.0-90.0 parts of deionized water. The silane monomer is one or more of compounds disclosed as Formula (j). The organic silicon emulsion is prepared from the silane monomer with low-hydrolysis-tendency Si-C group or Si-O-Si group; hydrolytic condensation and other side reactions can not easily occur in the emulsion polymerization reaction process, so that the production technique is easy to control; and the obtained organic silicon emulsion has excellent stability, can not have the phenomenon of stratification, floating oil or demulsification after being stored at normal temperature for more than 6 months, and can be widely used in the fields of architectural waterproofing, textile assistants, protection of historical relics and the like.

The invention relates to the technical field of an immunocolloid gold detection card, and discloses a detection card for detecting a benzodiazepine substance in health care products. The detection card includes a detection test strip, and the detection test strip is a colloidal-gold combination pad (2), a nitrocellulose membrane (3), and an absorbent pad (4) in order from a sample pad (1); the colloidal-gold combination pad (2) is a glass fiber gasket coated with a colloidal gold-labeled anti-benzodiazepine monoclonal antibody, the nitrocellulose membrane (3) is the nitrocellulose membrane provided with a detection line (5) and a quality control line (6), the detection line (5) is coated with a benzodiazepine-bovine serum albumin complex, and the quality control line (6) is coated with goat anti-mouse IgG. The invention also discloses a preparation method of the detection card for detecting the benzodiazepine substance in the health care products. The detection card can avoid the trouble of using complex identifiers or tracing buffer solutions, reduces sample differences, and improves sensitivity.

The invention discloses a telescopic anti-freezing full-physical crosslinked hydrogel material for a multi-mode flexible sensor and a preparation method thereof. The hydrogel material is an ionic conductor with a full-physical crosslinked structure and comprises a poly-N-hydroxyethyl acrylamide hydrogen bond network and a chitosan ion crosslinked network. N-hydroxyethyl acrylamide, chitosan and aphotoinitiator are taken as raw materials, and ultraviolet radiation curing and saline solution soaking crosslinking are carried out to obtain the poly-N-hydroxyethyl acrylamide hydrogen bond networkand the chitosan ion crosslinking network. The material has super-compressibility, high tensile strength, high toughness, self-restorability, self-healing property, fatigue resistance and mechanical stability, can maintain good mechanical properties and electrical conductivity in a low-temperature environment, and is expected to be applied to the fields of flexible electronics, wearable electronicequipment, tissue engineering, super capacitors, intelligent robots and the like.

The invention provides an active magnetic water additive used for efficient dust fall under a coal mine and belongs to active magnetic water additives. The additive is prepared from, by weight, 30-50 parts of inorganic electrolyte, surfactant, 0.3-0.7 part of polar organic matter and 7-10 parts of polymers, wherein inorganic electrolyte comprises sodium chloride, the surfactant comprises 1-2.5 parts of anion sodium dodecyl benzene sulfonate and 0.5-2 parts of non-ionic fatty acid methyl ester ethoxylate, the polar organic matter is fatty acid, and the polymers are polyethylene glycol. A solution prepared through the additive can have a coupling and coordination action with a magnetic field easily in the 300-400 mT magnetic field environment, active magnetic water with smaller surface tension and higher wettability is generated, and coal dust under a sedimentation well can be efficiently wetted through mist spraying. The additive is simple in formula, convenient to prepare and suitable for large-scale application of underground dust removal, and has the advantages of being environmentally friendly, low in cost and the like.

The invention discloses coal water slurry and a preparation method thereof. The coal water slurry is composed of 60-70wt% of coal powder, 29-39wt% of water and 0.5-1.5wt% of composite additive, and the composite additive comprises, by weight, 10-15 parts of acrylic acid and styrene polymer sodium salt, 45-50 parts of octaphenyl polyoxyethylene ether, 3-5 parts of polyacrylamide, 3-5 parts of sodium polyacrylate, 3-5 parts of hydroxyethyl cellulose, 5-10 parts of Arabic gum, 5-10 parts of inorganic salt, 10-15 parts of pH regulator, 1-3 parts of defoamer, 1-3 parts of emulsifier and 1-3 parts of sterilizing agent. The coal water slurry has the advantage of high concentration.

The invention discloses a prussian blue analogue and a preparation method, a negative electrode material and application thereof, which belong to the field of new energy batteries. The chemical formula of the Prussian blue analogue is KxMn[R(CN)6]1-y<vacancy>y.nH2O, x is more than or equal to 0 and less than or equal to 2, y is more than 0.3 and less than 1, and vacancy is a [R(CN)6] vacancy. The negative electrode material composed of the Prussian blue analogue is obtained at a rapid crystallization rate, and has relatively high crystal water content (24wt%) and relatively long Mn-N bond length (2.214 angstrom). The material has the advantages of being low in cost, environmentally friendly and high in Li storage capacity, transfer of 5 mol electrons can be achieved under the low potential, breakage and recombination of Mn-N bonds are involved, and stable circulation can be conducted for 1000 cycles or above with the high reversible capacity of 480 mAh g<-1> under the high current density of 1A g<-1>.

The invention discloses a preparation method of cutting thickening liquid, wherein polyethylene glycol and modified nanometer silicon dioxide core-shell particles are added into the mixed solution under the action of stirring and ultrasonic waves, are stirred and dispersed under ultrasonic waves for 1-2 hours until a homogeneous emulsion is formed, and the emulsion is placed in a vacuum drying oven and left standing for 24 hours to remove bubbles in the dispersion and obtain a shear thickening liquid. The modified nano-SiO2 core-shell particles are NiAl-LDH / SiO2 nanoparticles. The modified nano-silica core-shell particles are used as the disperse phase, and the modified nano-silica core-shell particles are used as the disperse phase through NiAl-LDH layered bimetallic hydroxides coated onthe surface of SiO2 formed a polymer layer on the surface of SiO2 microspheres. The electrostatic repulsion between particles is weakened by polymer oxide layer to some extent. The core-shell ions ofSiO2 can come closer to each other and form larger particle clusters under the shear action, which results in stronger shear thickening effect.

The invention discloses a method for preparing mineral fiber printing paper with excellent printing applicability. According to the method, activated sepiolite and wollastonite are subjected to superfine crushing, so that superfine powder of a large length-diameter ratio can be prepared, crystal form protection can be facilitated, a mineral fiber has a relatively large specific surface area, excellent adsorption properties for printing ink are achieved, and then the paper has excellent printing applicability; in addition, the mineral fiber is coated by modified starch, so that packing can be well combined with a plant fiber, the packing retention is improved, and the strength of paper is improved; the modified starch used in the method belongs to organic humidity control materials, is capable of regulating the relative humidity of a system in the paper making process and eliminating static electricity of paper, and has the advantages that paper shrinkage is reduced, and printing applicability is improved.

The invention provides a preparation method of nano zirconium oxide powder, comprising the following steps of: mixing inorganic zirconium salt, inorganic yttrium salt and water to obtain a mixed solution; dropwise adding the mixed solution into an ammonia water solution, and carrying out a precipitation reaction to obtain a precipitation solution; mixing the precipitation solution with an organicsolvent to obtain a precursor precipitation solution; filtering part of the precursor precipitation solution to obtain a precursor; mixing the precursor with the residual precursor precipitation solution, and filtering to obtain powder; and calcining the powder to obtain the nano zirconium oxide powder. By adding the organic solvent, the dielectric constant of the medium is effectively reduced, and the electrostatic repulsion between ions is reduced, so that the monodisperse spherical zirconium oxide powder is obtained; before calcination, the powder and the precursor precipitation solution are mixed, so that the particle surface defects and the surface activity are further reduced, the nano zirconium oxide powder with a low specific surface area is prepared, and the low specific surface area and high sintering activity of the zirconium oxide powder are realized.

The invention discloses a polycarboxylic acid type water reducing agent for concrete and belongs to the technical field of concrete additives. The water reducing agent is prepared from the following raw materials: methyl vinyl polyoxyethylene ether, methoxy polyethylene glycol methacrylate, fumaric acid, acrylic acid, sodium methallylsulphonate, mercaptoethanol, potassium peroxydisulfate, 2,2'-azobisisobutyronitrile, polyethylene glycol sodium stearate, sodium rosinate and phenol. According to the polycarboxylic acid type water reducing agent, a reinforcing system is formed by utilizing the polyethylene glycol sodium stearate, sodium rosinate and phenol and cooperatively improves the slump degree, water reduction rate and compressive strength of the concrete.

The invention relates to a modifier for a filter membrane for filter removal of leucocytes and a modification method of the filter membrane. The modifier for the filter membrane is composed of amidated modified silk fibroin, polyvinyl pyrrolidone and an acrylate copolymer with the mass ratio of (0.05-2):(0.2-1):1, wherein the acrylate copolymer is composed of a methyl methacrylate monomer and a dimethylaminoethyl methacrylate monomer. The modifier for the filter membrane can be dissolved in a polar solvent such as water to prepare a solution, and the filter membrane is subjected to coating treatment by an infiltration modification method; the filter membrane after being treated by the modifier for the filter membrane has relatively good wettability, stability and compatibility, has relatively high filter removal rate on both the leukocytes and platelets, and has relatively low modifier washout rate, and avoids soluble substance pollution.

The invention relates to a method of preparing a lignin-based positive ion organic flocculant by using paper mill sludge. The method comprises the following steps: extracting a raw material and directly dissolving by alkali liquor; carrying out centrifugal separation to obtain supernate; adjusting the pH of the solution; placing the adjusted solution in a reactor and heating to a certain temperature; sequentially adding N,N-dimethylformamide epoxy chloropropane, ethanediamine and triethylamine; and stirring to react. According to the method provided by the invention, a quantity of amino radicals with positive charges are introduced through an ethanediamine crosslinking method to change the charge electrical property of alkali lignin, so that the potential of the prepared flocculant is +20 to 35mV and the flocculant is positive ion type, and the zeta potential is high, the flocculation efficiency is high, and the addition is about 2mg / l. Therefore, the UV254 removal rate and the DOC removal rate respectively reach 80% and 65% without adding other compounding agents. Meanwhile, paper mill sludge is recycled, so that the paper industry is in sustainable development.

The invention provides a silicon nitride solution and a preparation method thereof. The preparation method of the silicon nitride solution comprises a step of mixing silicon nitride powder with deionized water, a step of adding hydrochloric acid, and a step of stirring to obtain the silicon nitride solution. The invention also provides a polysilicon ingot casting crucible and a making method thereof. The making method of the polysilicon ingot casting crucible comprises a step of heating a crucible body, and a step of spraying the silicon nitride solution onto the surface of the inner wall of the crucible body to obtain the polysilicon ingot casting crucible. Hydrochloric acid diminishes the pH value of the silicon nitride solution and makes a Zeta potential approach zero, so the intergranular static repulsion force is reduced, the agglomeration effect is enhanced, and agglomeration is easy, thereby the bonding strength between the silicon nitride solution and the crucible is increased, and a problem of crucible stickiness caused by coat shredding is avoided.