200 results about "Inorganic chemist" patented technology

The invention belongs to the field of macromolecule inorganic chemistry, and in particular relates to a method for preparing a graphene toughened silicon carbide ceramic composite material. Specifically, the method comprises the following steps: by taking graphite oxide as a carbon source, wrapping the surface of reduced graphene oxide with a layer of SiO2 granules by using a hydrothermal method so as to form a good interface layer between graphene and SiC, uniformly dispersing, and implementing carbon thermal reduction reaction at the interface of graphene and SiO2 in the high-temperature sintering process so as to growth silicon carbide crystal whisker and granules in situ, thereby improving the interface strength and the oxidation resistance, achieving an interface intensification function, improving crack expansion resistance and further improving the fracture toughness of ceramic. The method aims at the defects that graphene is poor in dispersity and high-temperature oxidation resistance in a conventional graphene / silicon carbide composite material, in-situ growth, crack self-healing and toughness mechanisms are applied to a preparation technique of a graphene / silicon carbide material, and thus graphene toughened silicon carbide ceramic with excellent mechanical properties and interface binding properties can be prepared.

The invention relates to a method for preparing fluorescent silica nanospheres and belongs to the technical field of inorganic chemistry and material synthesis. The main process of the method of the invention mainly comprises: (1) according to the prior art, calcining a certain amount of ethylene diamine tetraacetic acid (EDTA-2Na) at 250 to 400 DEG C in the presence of N2 in a tube furnace to obtain fluorescent carbon quantum dots; (2) mixing the fluorescent carbon quantum dots, deionized water, octadecylamine and methylbenzene, reacting at 160 to 180 DEG C for 12 hours, centrifuging, separating, collecting supernate and drying to obtain octadecylamine-modified fluorescent carbon quantum dots; and (3) mixing the octadecylamine-modified fluorescent carbon quantum dots with water, ethanol,ammonia water and ethyl orthosilicate, reacting at 40 DEG C for 1 to 12 hours, adding the ethyl orthosilicate and the hexadecy ltrimethyl ammonium bromide, reacting for 1 to 12 hours, washing with ethanol, centrifuging, drying and calcining at 300 DEG C for 3 hours and thus obtaining the fluorescent silica nanospheres.

The invention discloses a method for extracting lithium salt from aluminum electrolyte by utilizing fluoride roasting and acid leaching, and belongs to the technical field of inorganic chemistry. The method comprises the following steps: step 1: mixing materials; and step 2: carrying out fluoride roasting; and step (3): (1) carrying out acid leaching and filtering to obtain primary filtrate and primary filtered substances; (2) respectively treating the primary filtrate and the primary filtered substances to obtain secondary filtrate and secondary filtered substances; (3) respectively treating the secondary filtrate and the secondary filtered substances to obtain tertiary filtrate and tertiary filtered substances; and (4) respectively treating the tertiary filtrate and the tertiary filtered substances. According to the method disclosed by the invention, an element lithium in the electrolyte can be effectively extracted, so that energy consumption for electrolytic aluminum production is reduced; lithium carbonate chemical raw materials with a high additional value are recycled, and the used raw materials are common raw materials in the chemical field, so that the comprehensive average extraction cost is relatively low; various substances can be separated out, and the obtained substances are relatively high in purity; and the lithium element influence problem is solved for the aluminum electrolysis industry, benefits are increased, and the comprehensive level of the aluminum electrolysis industry in China is improved.

The invention provides a method for synthesizing zeolite ZSM-48, belonging to the technical field of inorganic chemistry and catalytic chemistry. The invention is characterized in that the method comprises the steps of mixing silicon source, aluminium source, alkali metal (M) source, structure guiding agent (R) N, N-dimethyl hexamethyleneimine quaternary ammonium base and water to prepare a reaction mixture with molar ratios that SiO2 / Al2O3 is equal to 60-2000, H2O / SiO2 is equal to 10-100, OH<-> / SiO2 is equal to 0.1-2.0, M / SiO2 is equal to 0.05-1.0 and R / SiO2 is equal to 0.05-1.0, carrying out hydrothermal crystallization on the reaction mixture at the temperature of 120-180 DEG C for 1-15 days, washing and drying products after crystallization is completed, thus obtaining the zeolite ZSM-48. By adopting the method provided by the invention, zeolite ZSM-48 with the ratio of silicate to aluminium being less than 150 can be synthesized.

The invention relates to a nanometer hierarchical pore MFI molecular sieve one-step synthesis method, belonging to the fields of catalytic chemistry, inorganic chemistry and physical chemistry; wherein, MFI molecular sieve can be Silicalite-1, ZSM-5 or TS-1, the specific surface is 400-1100m<2> / g and the total pore volume is 0.15-0.83 cm<3> / g. The preparation method is characterized in that commercial fluorocarbon / hydrocarbon surfactant is used as template agent of the mesoporous structure and the hierarchical pore MFI molecular sieve can be synthesized through one step reaction on the cooperative action between the commercial fluorocarbon / hydrocarbon surfactant and microporous molecular sieve template. The method is easy, the cost is low and the combination of mesoporous and microporous structures can be realized. The material not only has the characteristics of high activity and high hydrothermal stability of microporous molecular sieve, but also eliminates diffusion control, thus facilitating molecule reaction. The new material has wide application prospect in the fields of petrochemical engineering, chemical preparation, environmental catalysis and the like.

The present invention relates to inorganic chemistry, physical chemistry and catalytic chemistry technology. The present invention prepares composite pore zeolite molecular sieve with common silicon source and metal atom with doped skeleton as material, and water as solvent, and through hydrothermal treatment and calcinations process to obtain opened channels. In the hydrothermal treatment, material powder is prepared with hard template of rice hull, alkali styrene ion exchange resin or inorganic carbon, or composite template of mixture comprising hard template and organic amine or organic quaternary ammonium salt. The prepared molecular sieve has composite pore structure comprising micro pores and meso pores and pore walls of MFI, BEA, NaY or MOR crystal structure. The prepared molecular sieve may be used widely as adsorbent, catalyst and catalyst carrier in chemical field.

The invention discloses a novel and stable g-C3N4 / NiO photoelectric hydrogen production electrode preparation method, and belongs to the technical field of inorganic chemistry and photoelectrocatalysis. The g-C3N4 light absorber is nonmetal and is made of nontoxic and easily available materials. The preparation method solves the problem that in the prior art, usually a toxic cadmium metal chalcogenide as the light absorber, and utilizes the g-C3N4 as the photoelectric cathode light absorption agent and cocatalyst for the first time. The preparation method includes: 1 taking FTO electro-conductive glass as the substrate and using a hydrothermal method to prepare ordered NiO films; and 2 immersing the NiO / FTO electrode obtained by the last step in the saturated thiourea solution for 4h, and then placing the NiO / FTO electrode in a muffle furnace for calcining for 2h by 500DEG C, and then taking out and obtaining the g-C3N4 / NiO / FTO electrode. The preparation method is simple and easy to operate and is good for large-scale application.

The present invention is high heat stability ordered mesoporous aluminum phosphate material and its preparation process, and belongs to the field of inorganic chemistry and physical chemistry technology. The mesoporous aluminum phosphate material has composition of P2O5-Al2O3-MXOY, skeleton with primary and secondary zeolite structure units, 2D hexagonal structure, high heat stability and high degree of order. The preparation process includes synthesizing precursor solution containing the primary and secondary microporous aluminum phosphate zeolite structure units by using organic amine as template agent; and subsequent self-assembling process of the precursor and cationic surfactant to synthesize the ordered mesoporous aluminum phosphate material. The prepared mesoporous material has high specific surface area and atom connecting mode of microporous molecular sieve, may have several hetero atoms introduced, and may be used widely in chemical fields.

The invention relates to a multifunctional cleaning agent for oil fields, a preparation method therefor and applications thereof. The cleaning agent is composed of 0.2%-1.0% of composite nonylphenol polyoxyethylene ether active agents, 0.2%-1.0% of composite quaternary ammonium salt positive ion active agent chlorides, 0%-1.0% of composite acid pickling corrosion inhibitors, 0%-1.0% of composite Fe ion chelating agents, 0%-10.0% of organic carboxylic ester, and the balance being water. The cleaning agent has good acidolysis solution removing effects on inorganic chemistry scales of CaCO3, Fe2O3 and FeS at the temperature of 60-80 DEG C, has dispersion and melting effects on oil stains, wax scales and heavy oil stains, has a killing effects on oil field fungi, has a peeling effect on sticky dirt, and is suitable for cleaning of devices of oil field production well shafts, gathering pipelines, oil and water separation settling tanks, flocculation settling tanks, oil storage tanks, sewage storage tanks and the like.

The invention belongs to the field of inorganic chemistry, and particularly relates to an efficient zinc phosphate micro-nano anticorrosion agent preparation method, wherein the product is applied in the field of metal heavy corrosion. According to the present invention, a cycle ultrasonic cavitation effect and a high-temperature high-pressure water bath thermal effect are adopted to perform synchronous and synergetic regulation to prepare the efficient zinc phosphate micro-nano anticorrosion agent, wherein the synchronous and synergetic effect of the two effects is adopted so as to make the product system be well dispersed, ensure the uniformity of crystal nucleation and effectively solve the difficult problem of difficult synchronous regulation on the particle size and the crystallization degree of the nanometer crystal, and a microwave heating mode is adopted to dry the product so as to reduce the agglomeration; the prepared micro-nano zinc phosphate product has advantages of high purity, complete crystallinity, narrow particle size distribution, good dispersion and the like, wherein the effective corrosion protection time of the zinc phosphate micro-nano anticorrosion agent is up to 1056 h and is far superior to the effective corrosion protection time of the commercially available zinc phosphate anticorrosion material; and the method has characteristics of simple process and low cost, and is suitable for large-scale production.

The invention discloses a reduced graphene oxide / ZnIn2S4 photocatalyst and a preparation method and application thereof, belonging to the technical field of inorganic chemistry and photocatalysis. The photocatalyst is a semiconductor compound photocatalyst in which reduced graphene oxide is used as an electron transmission body, the separation of electrons from a hole is promoted and sheet ZnIn2S4 is closely packed and paved on the reduced graphene oxide, and the chemical formula is RGO / ZnIn2S4. A high-reducibility sheet RGO / ZnIn2S4 compound is synthesized by a one-step solvothermal method, and the reduction is finished without further photo-reduction or addition of a reducing agent (such as hydrazine). The compound photocatalyst prepared by the method has an efficient photocatalysis hydrogen generation effect, the preparation method is simple and easy to implement, and large-scale industrial popularization is facilitated.

The invention belongs to the field of catalysis of inorganic chemistry and chemical industry, and relates to a mesoporous composite oxide type solid super acidic catalyst and a preparation method thereof. The mesoporous composite oxide type solid super acidic catalyst of the invention comprises a component A and a component B, wherein the catalyst comprises 40 to 200 mass parts of component A and 5 to 80 mass parts of component B; the component A is one or two of zirconium oxide and titanium oxide; the component B is one or two of tungsten oxide, molybdenum oxide and cobalt oxide; the mesoporous composite oxide type solid super acidic catalyst has a worm-shaped mesoporous structure which consists of nanocrystallines uniformly compounded by the components; and the most probable aperture is 1 to 10nm. The catalyst prepared by the preparation method of the invention has superior catalytic activity and reusability, can be independently used as the catalyst or coated on the surface of cellular ceramic or metal carrier to serve as an integrated solid acidic catalytic material, and is a non-sulfuric acid promotion type solid super acidic catalyst.

The invention relates to a method for preparing novel mesoporous silica nano balls, and belongs to the technical field of inorganic chemistry and material synthesis. The method comprises the following main steps of: mixing a certain amount of diethyl ether, deionized water, ammonia water and tetraethoxysilane for reaction, adding a certain amount of tetraethoxysilane and cetyl trimethyl ammonium bromide (serving as a template agent), putting into a high pressure reactor, and performing reaction at 120 DEG C for 12 to 24 hours; and cleaning with the deionized water and ethanol solution, performing centrifugal separation, drying the sedimentation, and finally obtaining the mesoporous silica nano balls. The material has the advantages of high chemical stability and no toxin, and is expected to be applied to the aspect of biomedicines, such as fields of controlled release of medicines, biosensors and cell marking.

The invention belongs to the field of inorganic chemistry and photocatalysis, and particularly relates to a preparation method of a tantalum-tungsten mixed polyoxometallate photocatalyst with efficient hydrogen producing activity, and an application thereof to hydrogen production under photocatalysis. A synthetic method of the catalyst comprises the following steps of: enabling K8[Ta6O19] react with Na12[a-P2W15O56] in a stoichiometric ratio at the temperature of 45 DEG C in the presence of hydrogen peroxide to obtain yellow powder; dissolving the powder into an acid solution, and reflowing to obtain a colorless solution; and standing for a week to obtain a crystal product of an expected photocatalyst, wherein the structure and composition of the crystal product are determined through monocrystalline X-ray analysis. The catalyst is water-soluble and is kept stable, and the hydrogen producing rate is kept at 375mu.molh<-1> in 36 hours. In the currently-reported polyacid photocatalyst, the hydrogen producing rate and duration of the catalyst are maximized.

The invention relates to a novel metal organic framework material for catalysis degradation of an organic dye under visible light, and a preparation method thereof, and belongs to the cross field of inorganic chemistry, organic chemistry and material chemistry. According to the present invention, 9,10-bis(ethynylpyridine)anthracene is adopted as a ligand, the 9,10-bis(ethynylpyridine)anthracene, zinc nitrate hexahydrate / zinc chloride trihydrate and 1,4-terephthalic acid are subjected to a solvothermal reaction in an organic solvent, and washing and drying are performed to obtain a novel zinc metal organic framework crystal material. According to the present invention, the metal organic framework compound prepared by using the method has the regular framework structure and the adjustable particle size; and the method has characteristics of simple operation and cost saving, and provides the important significance in the technical field of catalysis degradation of the organic dye under the visible light.

The invention discloses a pyrite cinder separation, recovery and recycling method and belongs to the technical field of an inorganic chemistry industry. The method comprises carrying out suspended separation on calcium hydroxide and alumina through water, dissolving and separating alumina through an ammonium salt, dissolving iron sesquioxide / ferrous oxide in the pyrite cinder through strong phosphoric acid, filtering to separate the mixture of sulfur, phosphorus and silica insoluble with strong phosphoric acid from iron sesquioxide / ferrous oxide, and separating and recovering resource materials such as iron sesquioxide / ferrous oxide and alumina or aluminum hydroxide. The separated product can be used for an industrial raw material and agricultural fertilizer.

The invention discloses a high-purity and high-density sintered tungsten oxide material, which is characterized by the following: belonging to inorganic chemistry non-metallic element; making tungsten oxide burn densification without adding any sintering aid; making the purity of the tungsten oxide higher than 99% and the density not less than 6. 7g / cm3. This tungsten oxide can be used to target material of tungsten oxide film plating, panel display, photoelectric transformation, photochromism and so on domain.

The invention relates to a preparation method of a nest-like core-shell-structure Ag@mTiO2 nano composite material, belonging to the technical fields of inorganic chemistry and material synthesis. The invention uses a method combining hydrothermal synthesis and hydrothermal fluid corrosion to prepare the nest-like Ag@mTiO2 nano composite material which uses metal Ag nanoparticle as the core and laminar TiO2 as the three-dimensional porous shell. The material has larger specific area (300 m<2> / g), adjustable particle size and unique core-shell structure; and the synthesis conditions can be changed to accurately control the structure, shape, particle size and the like of the material. Thus, the Ag@mTiO2 nano composite material provided by the invention is hopeful to have potential application prospects in the fields of photocatalysis, Raman enhancement, biomedicine and the like.

The invention relates to a novel porous metal organic framework material for CO2 adsorption and separation and a preparation method of the porous metal organic framework material, and belongs to the cross field of inorganic chemistry, organic chemistry and material chemistry. The method comprises the steps of taking 2,5,8-tri-(3,5-dicarboxyl aniline)-s-heptazine as a ligand to perform solvothermal reaction with cupric nitrate or copper perchlorate in a mixed solvent formed by an organic solvent and water, washing, drying, and obtaining the novel porous metal organic framework material. The porous metal organic framework material prepared by the method has a regular crystal structure, uniform pore size distribution, excellent CO2 selective adsorption ability, and an important significance in the technical field of CO2 storage and separation.

The invention relates an organic fertilizer fermented by rice husk, which comprises the following raw materials by weight: 2-4 parts of earthworm manure, 10-14 parts of rice husk, 8-10 parts of wheat bran, 8-10 parts of corn straw, 3-5 parts of perlite, 16-20 parts of clay, 0.02-0.05 parts of Rw fermentation bacteria agent, 0.2-0.4 parts of calcium chloride, 0.05-0.1 parts of polyacrylamide, 0.1-0.3 parts of humic acid, 0.2-0.4 parts of potassium humate, 2-4 parts of urea, 1-2 parts of potassium permanganate, 0.4-0.5 parts of auxiliary agent and a proper amount of water. A preparation method of the organic fertilizer comprises the following steps: adding rice husk, wheat bran and corn straw in water for boiling, softening a physical and chemical structure of the organic fertilizer for conveniently decaying and fermenting the raw materials, clay and perlite are taken as the carriers, the perlite has adsorption effect to an inorganic chemistry material, nutriment can be slowly released, and slow release effect is realized, the inorganic chemistry material is stirred and dissolved under supersonic wave condition, melting is thoroughly, the inorganic chemistry material is uniform after being mixed, and agglomeration is not easy after the inorganic chemistry material is molten, and uneven soil fertilizer condition can be avoided. The organic fertilizer can reduce the usage of the chemical material, and has benefit to environment, human and animal and nature.

The invention belongs to the technical field of inorganic chemistry and particularly relates to a one-step in-situ synthesis method for an organic and inorganic composite anticorrosive pigment. According to the one-step in-situ synthesis method, heat emitted when phosphate radical and zinc ions react to genera zinc phosphate is skillfully utilized for improving the temperature of a reaction system, so that the solubility of benzotriazole is greatly improved; the dissolved benzotriazole is attached to the surface of a zinc phosphate crystal nucleus to effectively inhibit growth of a zinc phosphate crystal, and the particle size is controlled in the nanometer level; when reaction between zinc nitrate and sodium phosphate is finished, the temperature of the reaction system is decreased, the solubility of benzotriazole is also reduced along with decreasing of temperature, benzotriazole is separated out from the system and firmly covers the surface of zinc phosphate nanocrystal, and finally the zinc phosphate / benzotriazole organic and inorganic composite anticorrosive pigment with the fixed composition and stable structure is obtained. The obtained product has the advantages of being good in dispersity, small in particle size, excellent in anticorrosive performance and the like.

The invention relates to a hydrothermal synthesis method of a tin dioxide nano material, belonging to the technical field of inorganic chemistry and material synthesis. The hydrothermal synthesis method is characterized by comprising the following step of: with stannous sulfate (SnSO4) as a tin source and water as a solvent, preparing the tin dioxide nano material with flower-like characteristic and uniform morphology through a simple hydrothermal process under the auxiliary crystallization action of small molecular alkali tetrapropylammonium hydroxide (TPAOH), wherein the tin source of the raw materials can be stannous chloride (SnCl2), sodium stannate (Na2SnO3) or the like and the SnO2 nano material with uniform morphology can be obtained by using the tin source. The method has the advantages of simpleness in operation, controllable conditions, easiness in obtainment of the raw materials, no addition of organic solvents in the reaction process, large specific surface area of the prepared material, uniform morphology, good crystallinity and the like and has wider application prospects in the fields such as lithium batteries, gas sensors, photocatalysis, solar cells and the like.

The invention relates to a nuisance-free growth fattening pig feed, which provides the nuisance-free growth fattening pig feed with fast pig growth and high meat quality. The nuisance-free growth fattening pig feed comprises the following components by weight: 50-70 parts of corn, 10-20 parts of soybean meal, 5-15 parts of washed rice bran, 5-15 parts of wheat bran, 2-10 parts of corn germ meal, 0.5-1.5 parts of stone flour, 0.2-1.0 parts of calcium hydrogen phosphate, 0.2-0.5 parts of lysine, 0.02-0.2 parts of threonine, 0.1-0.15 parts of choline and 0.2-0.5 parts of salt. The pigs fed by the feed have the advantage of fast growth, feed benefit is high, no pesticide residues is left in pork after the pigs are killed, no organic or inorganic chemistry poison is required, no antibiotic is left, no pathogenic microorganism is generated, mycotoxin can not exceed a standard nuisance free requirement, and environmental pollution due to pig night soil can be mitigated.

The invention discloses a two-dimensional metalloporphyrin-based COF (chip on film) material as well as a film preparation method and the application thereof, and belongs to the technical field of inorganic chemistry. In a high-pressure reaction vessel, CuP-DHNDA-COF is obtained by performing an aldimine condensation reaction and filtering. The method has the advantages of being simple in operation, high in yield, easy in large-scale production and the like; the material CuP-DHNDA-COF serving as a photocatalyst is used for degrading methylene blue dye, and the good capability of photocatalyticdegradation of organic pollutants is shown. Therefore, the material CuP-DHNDA-COF has potential application on the aspect of wastewater treatment of the dye.

The present invention provides a chromium metal organic framework catalytic material and a preparation method thereof, belongs to the cross technical field of inorganic chemistry, organic chemistry and material chemistry. The chromium metal organic framework catalytic material consists of 2-amino p-phthalic acid and chromium salt coordinated in the form of hexa-coordinate, and a quaternary phosphonium salt ionic liquid is modified to the amino group of the 2-amino p-phthalic acid The preparation method of the chromium metal organic framework catalytic material comprises first preparing a metal organic framework substrate by a solvothermal method, and then modifying the quaternary phosphonium salt ionic liquid to the substrate. The chromium metal organic framework efficiently catalyzes reaction of CO2 with epoxy compound in the presence of no homogeneous catalyst to form cyclic carbonic ester, and reaches a catalytic yield of more than 98%. The preparation method of the chromium metal organic framework catalytic material has the advantages of simple and easy synthetic method, and good reproducibility of synthesized samples.

The invention discloses a nano SnO2 hollow microsphere, a preparation method and applications thereof, and belongs to the technical field of inorganic chemistry and material preparation. The preparation method comprises the following steps: dissolving a tin source and a sugar source into water according to a mole ratio of 1:1-3, carrying out hydrothermal reactions under the assistance of microwaves, subjecting the reaction products to centrifugation and washing, drying, and burning the solids to obtain nano SnO2 hollow microspheres. The nano SnO2 hollow microsphere has the characteristics of low density, high specific surface area, stable structure, and surface permeability, and can be used a photocatalyst for preparing an oxygen indictor. The hollow microsphere can be mixed with an electron donor, an oxidation-reduction dye, and a polymer binding material, and then the mixture is dispersed under ultrasonic waves to prepare the oxygen indictor. The preparation method of nano SnO2 hollow microsphere has the advantages of simpleness, practicality, low cost, environment-friendliness, and good using effect. The prepared nano SnO2 hollow microsphere can be used to prepare an oxygen indictor to indicating oxygen state in packages of food and medicine so as to evaluate the freshness.

The invention relates to synthesis and characteristic determination of a novel Schiff base ligand and platinum complex, and belongs to the coordination chemistry field of inorganic chemistry, wherein the phosphorescence emission can be achieved effectively. According to the novel Schiff base ligand and platinum complex light-emitting material, the maximum ultraviolet absorption wavelength of the platinum complex is 487 nm, the maximum phosphorescence emission wavelength is 618 nm, and the decomposition temperature is 295 DEG C. The novel complex is convenient to synthesize, high in thermostability and not prone to decomposition under high temperature and can be prepared through a simple instrument.

A process for producing a hydrogenated ester by hydrogenating an unsaturated group-containing ester having a specific structure by using a hydrogenating catalyst so as to obtain a hydrogenated ester with a high selectivity. It is preferred that the unsaturated group-containing ester as the raw material is diluted with an inert solvent and / or the concentration of carboxylic acid contained in the raw material is made 1 wt. % or less so as to effect a hydrogenation reaction. The hydrogenating catalyst to be used for the above hydrogenation may preferably be one comprising at least one metal selected from Group 8 elements, Group 9 elements, and Group 10 elements in the periodic table according to Nomenclature of Inorganic Chemistry, Revised Edition, 1989, International Union of Pure and Applied Chemistry, and preferably has an acidity of 1.0×10−1 mmol / g or less.

The invention relates to a flame retardant preparation technology, and belongs to the field of inorganic chemistry and composite materials. The invention discloses a phytate composite flame retardantfor polyamide and a preparation method of the phytate composite flame retardant. The phytate composite flame retardant comprises phytate functionalized by ionic liquid, ammonium polyphosphate and pentaerythritol; and after the flame retardant is mixed with polyamide, the mass fractions of the phytate functionalized by the ionic liquid, the ammonium polyphosphate and the pentaerythritol in the polyamide blend are respectively 0.1%-5%, 5%-25% and 1%-5%. The composite flame retardant disclosed by the invention is low in cost, simple in preparation method and excellent in polyamide flame-retardanteffect.