88results about How to "Improve freezing point" patented technology

The invention discloses an environment freeze protection stone paint, which comprises the following raw material components according to the parts by weight: 0.1-5 of fibrin aqueous solution of 1-4% concentration, 0.8-1.2 of glycol, 50-70 of colored sand of 41-80 mesh, 5-25 of colored sand of 81-120, 17-23 of KE025 acrylic emulsion, 0.6-0.9 of alcohol ester-12 addition agent, 0.02-0.06 of foam killer, 0.01-0.1 of thickness agent and 0.02-0.06 of neutralizing agent. Meanwhile, the invention also discloses a preparation method for the stone paint. The stone paint has the environment and freeze protection performance, provides powerful guarantee for being suitable for winter construction, in particular to various severe conditions of winter construction in the northern area of our country.

A carrier of hydrocatalyst for the hydrocracking of heavy oil, hydromodifying of poor diesel oil, etc is prepared from amorphour silicon aluminium, modified beta-molecular sieve and aluminium oxide. Its preparing process is also disclosed. Said catalyst has high catalytic activity.

The invention relates to a cold-resistant anti-fusible aqueous film forming foam extinguishing agent. The cold-resistant anti-fusible aqueous film forming foam extinguishing agent consists of the following gradients in percentage by mass: 12-30 percent of a composite hydrocarbon surfactant, 4-6 percent of a compounded fluorocarbon surfactant, 0.5-1 percent of a foam stabilizer, 20-50 percent of an antifreeze agent, 3-5 percent of a solubilizer and the balance water, wherein the composite hydrocarbon surfactant is a composition of an ampholytic surfactant and a nonionic surfactant. The cold-resistant anti-fusible aqueous film forming foam extinguishing agent disclosed by the invention is mainly applied to prevention and extinguishing of fire caused by hydrocarbon substances and polar solvents (water-soluble substances), can be normally used at an environment temperature of -25 DEG C and is especially applicable to storage and use in extremely-cold regions. Besides, by adopting a daily-necessity-level hydrocarbon surfactant and a fluorocarbon surfactant which is free of PFOS (Perfluorooctane Sulfonates), the cold-resistant anti-fusible aqueous film forming foam extinguishing agent disclosed by the invention is good in degradation property, quick and safe in degradation and free of environmental pollution.

The invention relates to a waterproof coating, in particular to a waterproof coating of a carton, which comprises the following components in weight part: 30-120 parts of paraffin micro-emulsion, 50-90 parts of simethicone, and 4-8 parts of emulsifier. The waterproof coating is prepared according to a method as follows: (1) heating the paraffin micro-emulsion to 50-180 degree C; (2) adding simethicone and stirring for 0.5-3 hours; and (3) adding the emulsifier, stirring at a high speed for 10-40 minutes, and cooling to the room temperature. The waterproof coating of the carton, disclosed by the invention, has no pollution on the human body and the environment, can be combined with the base material firmly, and has excellent waterproof property.

The invention discloses an anti-boiling, anti-scale and anti-freeze solution and belongs to the technical field of anti-freeze solutions. The anti-boiling, anti-scale and anti-freeze solution is obtained through reaction of 100 parts to 120 parts of ethanediol, 60 parts to 80 parts of deionized water, 15 parts to 30 parts of corrosion inhibitor, 5 parts to 10 parts of silicate, 6 parts to 8 parts of silicate stabilizer, 2 parts to 4 parts of mildew preventive, 5 parts to 10 parts of pH modifier, 1 part to 3 parts of defoamer and 1 part to 5 parts of colorant, wherein the pH modifier is disodium hydrogen phosphate. According to the anti-boiling, anti-scale and anti-freeze solution, by increasing the proportion of the deionized water in the antifreeze, the boiling point is raised while the freezing point is lowered, the quality of the anti-freeze solution is improved to a certain extent, the long-acting anti-boiling performance is achieved by adding various auxiliaries in the subsequent process, and the anti-boiling, anti-scale and anti-freeze solution is low in price and free of pollution, sediment and scaling. A preparation method of the anti-boiling, anti-scale and anti-freeze solution is simple in step, environmentally friendly and easy to carry out.

The invention discloses a methanol diesel oil additive and simultaneously discloses methanol diesel oil with the methanol diesel oil additive. The methanol diesel oil prepared by the invention is prepared by mixing 0.04-0.07 part of ferrocene, 2-5 parts of acetone, 4 parts of diemethyl carbonate, 2-3 parts of isobutanol, 2-3 parts of toluene, 70 parts of diesel oil and 20-25 parts of methanol. The methanol diesel oil has the advantages of low corrosion, good intersolubility and swelling property, uniform texture, high flash point, low condensation point and high cetane number, is safe to use and meets all indexes of automobile diesel oil GB19147-2009. The methanol diesel oil can be applied to internal-combustion engines, general engines, power plant fuels, burner substances and the like, thus the applicable range of the methanol diesel oil is wide.

The invention provides a sea buckthorn berry oil preparation method which is implemented by the following steps: (1) cleaning sea buckthorn berries; (2) quickly freezing; (3) pulping; (4) hydrolyzing pectinase; (5) precipitating with alcohol; (6) freezing to stratify sea buckthorn berry oil; (7) extracting raw oil; (8) recovering ethanol by distillation; (9) carrying out secondary freezing and thawing to separate the sea buckthorn berry oil; and (10) refining to obtain the sea buckthorn berry oil. In the invention, poisonous and odorous organic solvents are not used, and the extraction process cost is low, thereby ensuring that the preparation method has a high use value.

The invention relates to a cold-resistant aqueous film forming foam extinguishing agent. The cold-resistant aqueous film forming foam extinguishing agent is prepared from the following components in percentage by mass: 12 to 30% of a composite hydrocarbon surfactant, 2 to 5% of a fluorocarbon surfactant, 0.1 to 1% of a foam stabilizer, 20 to 50% of an antifreeze agent, 3 to 5% of solubilizer, and the balance of water, wherein the composite hydrocarbon surfactant is a composition of an ampholytic surfactant and a nonionic surfactant. The cold-resistant aqueous film forming foam extinguishing agent is applicable to extinguishing of fire caused by hydrocarbon substances, can be normally used at the environmental temperature of -25 DEG C, and in particularly suitable for the super cold area; in addition, the hydrocarbon surfactant at grade of daily necessities, and the fluorocarbon surfactant free of PFOS (Perfluorooctane sulfonates) are adopted, so that the cold-resistant aqueous film forming foam extinguishing agent is high in degrading performance, can be quickly and safely degraded, and is free of environmental pollution.

The invention belongs to the field of deicing and snow-melting agents, and discloses a biomass environment-friendly non-chlorine deicing and snow-melting agent and a preparation method thereof. The deicing and snow-melting agent is prepared from 10-30 parts of tap water, 15-35 parts of glucose degradation product, 6-20 parts of starch degradation product, 8-18 parts of saccharose, 7-18 parts of monoglyceride citrate and 2-5 parts of corrosion inhibitor; the preparation method comprises the steps that firstly, the glucose degradation product and the starch degradation product are prepared; thenthe tap water is added into a reaction kettle, the temperature rises to 60-80 DEG C, the glucose degradation product and the starch degradation product are added, and mixing reaction is carried out for 1-3 h; then the saccharose, the monoglyceride citrate and triisopropanolamine are added in sequence, and full stirring and mixing reaction is carried out for 1-2 h; and lastly, after the reactant is mixed uniformly and dissolved into one phase, cooling and discharging are carried out. The biomass environment-friendly non-chlorine deicing and snow-melting agent and the preparation method thereofhave the advantages that the obtained product has strong snow-melting and deicing abilities and a weak corrosive effect, the raw material is basically biomass, the biodegradability is high, and the biomass environment-friendly non-chlorine deicing and snow-melting agent belongs to an environment-friendly product.

A method for producing phase change energy storage wax comprises the following steps: refining a Fischer-Tropsch synthetic wax raw material through hydrogenation reaction to obtain Fischer-Tropsch refined wax; primarily separating the Fischer-Tropsch refined wax to obtain a plurality of fractions; selecting a target fraction from the plurality of fractions to carry out sweating treatment to obtainphase change energy storage wax, wherein a sweating device adopted in the sweating treatment is provided with a tubular heat exchanger structure. According to the method, the raw material treatment process is simple, and the production cost is low. By adopting the improved sweating process, the solid-liquid separation efficiency can be improved, the separation effect is improved, and finally theproduct quality is improved.

The invention relates to a concrete antifreezer which is prepared by water reducing mother liquid, air entraining agent, subcritical hardening promoter, slump retaining agent, etc. The concrete antifreezer can be used for concrete pumping in winter, improves the pumpability of concrete on the premise of achieving the freeze-proof effect, solves the problem that concrete slump constant is lost after the concrete is added with the traditional antifreezer, has good effect, and enhances the durability of concrete.

The invention discloses a method for preparing a refining agent from dechlorinated light salt brine. The method comprises the following steps of: mixing free chlorine-containing light salt brine which is generated after electrolyzing ultrapure saline in an ionic membrane electrolytic cell with free chlorine-containing condensed water from a chlorine system, and then subjecting the mixed light salt brine to vacuum dechlorination and chemical dechlorination to obtain the dechlorinated light salt brine. The dechlorinated light salt brine is suitable for directly preparing sodium sulfite and sodium carbonate, and can also be used for preparing ferric trichloride after being acidized in stead of production water. According to the invention, the refining agent preparation in brine purification in the chlor-alkali industry widely adopted at present is improved, and the dechlorinated light salt brine in the system is directly used for preparing the refining agent in stead of external production water or purified water.

The invention relates to coal-based environment-friendly solvent oil and a preparation method thereof. The method at least comprises the following steps of: performing the hydrorefining of a fixed bed at the reaction temperature of between 250 and 420 DEG C under reaction pressure of 5.0 to 20.0 MPa under the condition that space velocity is 0.3 to 3.0 h<-1> and the volume ratio of hydrogen to oil is (500:1)-1,500:1, wherein a catalyst is Ni-W, Ni-Mo or Ni-W-Mo series of hydrorefining catalysts; and performing rectifying separation, namely cutting cut fractions by rectification and fractional distillation within the range of boiling points of between 140 and 220 DEG C to obtain the solvent oil. The environment-friendly solvent oil has the characteristics of low viscosity, low aromatic hydrocarbon content, low sulphur and nitrogen content, no toxicity, no color, narrow distillation range, high chemical stability and dissolution selectivity, high volatility, environment-friendliness and the like, and is mainly used as solvents and diluents in paint industry and spinning, printing and dyeing and textile printing industries.

The invention discloses a hydrogenation method for Fischer-Tropsch synthesis oil. The hydrogenation method comprises the following steps: (1) mixing Fischer-Tropsch synthesis oil and hydrogen, and allowing the obtained mixture to enter a hydrocracking reactor for a reaction under the action of a hydrocracking catalyst, wherein the average pore size of the hydrocracking catalyst tends to decrease along the flow direction of a material flow; (2) separating a hydrogenation effluent obtained in the step (1) into a gas phase and a liquid phase, recycling the gas phase and allowing the liquid phase to enter a fractionation column; and (3) carrying out fractionation in the fractionation column to obtain naphtha, an aviation fuel, diesel and tail oil and recycling the tail oil to the hydrocracking reactor. The method can greatly improve the yield of light oil, reduce the freezing point of the aviation fuel and the condensation point of diesel.

The invention relates to a power-assisted steering oil composition, and mainly aims to solve a problem that the power-assisted steering oil suitable for extremely cold areas is not found at present. The power-assisted steering oil composition comprises the following components by weight: 93.525-94.5% of base oil, 0.14-0.3% of a dispersant, 0.35-0.5% of a pour point depressant, 0.03-0.05% of a metal deactivator, 4.0-5.0% of a viscosity index improver, 0.3-0.5% of an extreme pressure antiwear agent, 0.06-0.1% of an antioxidant, 0.03-0.08% of an oxidation and corrosion inhibitor, 0.005% of an anti-foam agent, 0.08-0.1% of detergent and 0.08-0.1% of an anti-rust agent. The power-assisted steering oil composition has advantages of excellent low temperature fluidity and viscosity temperature property, high flash point, and good anti-foam property.

The invention relates to a waterless liquid coolant for an engine under extreme conditions and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing, by weight, 10 to 20 parts of imidazole ionic liquid, 10 to 30 parts of dipropylene glycol and 40 to 60 parts of propylene glycol under stirring so as to obtain base liquid; adding 0.2 to 2 parts by weight of an organosilicon antifoaming agent into the base liquid and carrying out uniform mixing under stirring; adding 0.7 to 8 parts by weight of a composite corrosion inhibitor into a mixed solution obtained in the previous step, carrying out heating to 70 to 80 DEG C and then carrying out uniform mixing under heating and stirring; and adding 5 to 10 parts by weight of a viscosity-reducing agent into a mixed solution obtained in the previous step and carrying out carrying out uniform mixing under stirring. The invention has the beneficial effects that the waterless liquid coolant has a freezing point of less than -65 DEG C and a boiling point of 255 DEG C, and has long-acting and excellent corrosion resistance; the waterless liquid coolant can rapidly form a metal oxide passive film on the surfaces of a plurality of metals so as to realize anticorrosion and construction of an activated adsorption film-forming corrosion mitigation system; special-effect aluminum corrosion inhibitor, i.e., sodium metasilicate, can protect aluminum structural members in the engine; and tolyltriazole can protect copper structural members in the engine.

The invention relates to a preparation method of a catalyst used for preparing a liquid fuel by oil and fat hydrogenation. The method comprises the following specific preparation steps: firstly, mixing a calcined ZSM-22 molecular sieve and an amorphous oxide precursor, performing strip extrusion, performing molding, and performing calcination to prepare a carrier precursor; filling pore channels of the carrier precursor with monomer molecules of a polymer, and performing heating treatment to obtain a carrier with partially-covered molecular sieve acidic sites and partially-blocked molecular sieve pore channels; and supporting a metal active component on the carrier, performing drying, and performing reduction to obtain the target catalyst. Compared with a catalyst prepared in the prior art, the catalyst prepared by adopting the method provided by the invention has the higher isoparaffin selectivity and yield in the process of preparing the liquid fuel by oil and fat hydrogenation.

The invention relates to a carbon nanotube water-free cooling liquid which comprises 0.5-10% of a carbon nano tube, 89.45-99% of propylene glycol and 0.05% of cetyl trimethyl ammonium bromide. According to the carbon nanotube water-free cooling liquid, due to the addition of the carbon nanotube, the heat conductivity coefficient is greatly improved, and at the same time the ice point can be -60 DEG C, the boiling point is as high as 180 DEG C, and the heat conductivity coefficient of the carbon nanotube water-free cooling liquid can be more than 0.468W / mK at 100 DEG C and is twice as much as the heat conductivity coefficient (0.234W / mK) of a propylene glycol basic liquid.

The invention discloses a paperboard waterproofing agent and a preparation method thereof and relates to the technical field of paper waterproofing. The paperboard waterproofing agent comprises a paraffin microemulsion, dimethyl silicone oil, waterborne polyurethane, acrylic acid, butyl acrylate, calcium hydroxide, oligolactic acid, chamomile, polyoxyethylene oleate, ammonium persulfate, isopropanol, ethyl acetate, xylene, ammonium hydroxide, an emulsifier, a dispersant and deionized water. In use, the paperboard waterproofing agent is diluted by water of which the use amount is 5 to 10 times that of the paperboard waterproofing agent, and a paper to be subjected to waterproof and moistureproof treatment is coated mechanically and is dried at a high temperature so that scattered water-caused destruction of box strength is reduced, the box is effectively protected and good water prevention effects are obtained. The preparation method has simple processes. The paperboard waterproofing agent prolongs a carton service life, reduces material consumption and has energy saving and environmental protection effects.

The invention discloses an extraction system for extracting lithium and boron by separating calcium from calcium-containing brine by a secondary amid / alkyl alcohol composite solvent, an extraction method and application of the extraction method. In the extraction system, secondary amid and alkyl alcohol serve as extracting agents for extracting lithium and boron correspondingly and consist of single compound or a mixture of more than two compounds; the total number of carbon atoms in the molecules is 12 to 18 and 8 to 20 correspondingly, and the freezing point of the extraction system is lessthan 0 DEG C. Single-stage or multi-stage countercurrent extraction is conducted under the conditions that the volume ratio of an organic phase to a brine phase is (1-10):1, the density of the brine is 1.30 to 1.56 g / cm<3>, the pH value of the brine is 0 to 7 and the temperature is 0 to 50 DEG C, an aqueous phase with low calcium-lithium ratio is obtained through back extraction, and lithium chloride, lithium carbonate, lithium hydroxide and boric acid are obtained respectively through concentration, impurity removal and preparation. The secondary amide is simple in molecular structure, and the lithium and the boron can be extracted simultaneously by the composite solvent improved by the alkyl alcohol; multi-stage extraction rate is high, back extraction is conducted by using water and acid and alkali consumption is greatly reduced; and the extraction separation flow is shortened, and the extraction system has small solution loss and is suitable for development of oilfield brine.

The invention provides high-energy carbon alcohol clean fuel slurry and a preparation method thereof. The clean fuel is prepared from the following components in percentage by weight: 45-63 percent of pulverized coal which is over 300mesh and 37-55 percent of methanol, as well as, by total weight of the pulverized coal and methanol, 1-2 percent of a stabilizing agent, 1-3 percent of a dispersing agent, 0.1-0.3 percent of micron-metal powder, 0.1-0.2 percent of a catalyst, 0.5-1 percent of a desulfurizing agent, and a pH regulator which is used for regulating the pH value to 6.5-7.5. The clean fuel has the advantages of high combustion rate, high heat value, low cost and small emission of sulfur dioxide and nitrogen oxide, and can be widely applied to various boilers, diesel engines, gas turbines, tunnel type ceramic firing kilns, refractory brick down-draft kilns, hot-blast stoves of ceramic spray drying towers, rotary cement kilns, iron ore sintering machines and the like.

The invention relates to a cold-resistant alcohol-resistant aqueous film-forming foam fire extinguishing agent, which comprises, by mass, 4-10% of a fluorine surfactant, 15-20% of a polyol type surfactant, 3-6% of a foam stabilizer, 2-5% of a solubilizer, 2-4% of an anti-burning agent, 20-30% of an anti-freezing agent, and the balance of water, wherein the fluorine surfactant is an anionic geminifluorine surfactant having a fluorocarbon chain length of 4 carbons. According to the present invention, the cold-resistant alcohol-resistant aqueous film-forming foam fire extinguishing agent is mainly used for preventing and extinguishing alcohol-based solvent fire disasters, can be normally used at an ambient temperature of about -48 DEG C, is especially suitable for storage and use in particularly cold regions, does not contain PFOA / PFOS, has good degradation performance, can be rapidly and safely degraded, and cannot cause environment pollution.

The invention relates to a crude oil pour-point depressant and a preparation method thereof. The preparation method comprises that maleic anhydride and benzoyl peroxide are added into a toluene solvent, styrene is added into the mixed solution, the mixed solution is heated to a temperature of 80-85 DEG C and undergoes a reaction to produce a milk white pasty product, the reactants are cooled to a room temperature, the product is filtered and is dried at a temperature of 60 DEG C in vacuum, the product and p-toluenesulfonic acid are added into toluene, organic alcohol is added into the mixture, the mixture is cooled to form a flavescent jelly-type material, wherein a mole ratio of the organic alcohol to styrene-maleic anhydride polymer of 1: 1, and the flavescent jelly-type material is dissolved in the organic solvent so that the crude oil pour-point depressant is obtained. The crude oil pour-point depressant is a mixture of the polymer and the organic solvent, and the polymer contains carboxylic acid which can react with organic amine in colloid and asphaltene so that crude oil condensation point and viscosity are obviously improved and amine in colloid and asphaltene of crude oil producing modification influence on the crude oil can be inhibited. The crude oil pour-point depressant improves crude oil modification effects.

The invention relates to a preparation method of a hydroisomerization / cracking catalyst. The method includes the following concrete steps: treating a potassium type or sodium type ZSM-22 / ZSM-23 composite molecular sieve containing a template with an alkali solution of a certain concentration; washing an obtained product with deionized water and drying and roasting to remove the template; exchanging by using an ammonium nitrate solution, filtering, washing with deionized water, and drying and roasting to prepared a hydrogen type ZSM-22 / ZSM-23 composite molecular sieve; mixing kneading, formingand roasting the hydrogen type ZSM-22 / ZSM-23 composite molecular sieve, amorphous oxides and an acid solution to prepare a carrier; and immersing the carrier into an aqueous solution of soluble saltscontaining active components, and then drying and roasting to prepare the catalyst. Compared with a catalyst used by the prior art, the catalyst provided by the invention has better catalytic activityand target product selectivity in a hydroisomerization conversion process of Fischer-Tropsch synthetic wax.

The invention discloses an efficient cotton defoliating agent and a synthesis method thereof. The defoliating agent is prepared from, by weight, 20-40 parts of ethephon, 10-20 parts of magnesium chlorate, 10-25 parts of thidiazuron, 12-22 parts of coronatine, 8-15 parts of polycondensated naphthalenesulfonate, 2-6 parts of carrageenan, 10-20 parts of moist organosilicon auxiliary, 15-20 parts of sodium lignin sulfonate, 8-17 parts of hydroxyquinoline, 3-10 parts of ethylene glycol and 35-55 parts of deionized water. The preparation process is simple, the prepared defoliating agent can improve the cotton defoliating rate, is not harmful to cotton and has environment-friendly and non-toxic effect. In addition, the residues of the efficient cotton defoliating agent do not cause soil pollution.

A ship LNG vaporization system supplying heat through river water comprises a river water header pipe, a stop valve, an outer cooling pump, an intercooler, a smoke water draining sleeve, a glycol heat exchanger, a stop check valve, an LNG vaporizer and an internal combustion engine. According to the ship LNG vaporization system supplying the heat through the river water, the river water is extracted, excess heat produced by the internal combustion engine is absorbed by the intercooler to heat the river water, the river water is subjected to secondary heating through high-temperature tail gas exhausted by the internal combustion engine, thus, the river water can stably provide a heat source for the LNG vaporizer for a long term, and stable and efficient work of the LNG vaporizer is ensured.

The invention discloses a ceramic fiber-added compound snow-melting deicing agent special for urban roads. After sugarcane leaves and hemp palm barks are swelled and filled with polyacrylic acid emulsion, the cell walls are enhanced; the gaps in staggered fiber space is filled with the resins, so that the combination between fiber and fiber is enhanced; more micro-pores are introduced after carbonization, so that the adsorption capacity can be improved; according to the invention, glacial acetic acid is replaced by pyroligneous acid, modified fluorite powder is taken as calcium and magnesium precursor, the two materials are mixed to form the snow-melting agent, and the prepared snow-melting agent and anti-sliding auxiliaries are wrapped and pelletized and then are dried, so that the compound snow-melting deicing agent is acquired; the compound snow-melting deicing agent is added with the ceramic fibers, so that the strength is high and the compound snow-melting deicing agent is difficult to be crushed by automobiles; after the snow and ice are melted, the freezing point can be quickly reduced; the ceramic fiber-added compound snow-melting deicing agent can absorb heat so as to accelerate the snow melting; the residual liquid can be absorbed by the anti-sliding auxiliaries so as to prevent the pavement from being corroded; the method provided by the invention is low in cost, high in product fluidity and good in snow-melting effect.

The invention discloses a waterproof material for a toilet and a preparation method of the waterproof material and relates to the technical field of waterproof materials. The waterproof material comprises the following raw materials in parts: 70-80 parts of modified starch, 55-65 parts of inorganic powder fillers, 45-50 parts of cis-1,4-polyisoprene rubber, 35-40 parts of aluminum stearate, 30-35 parts of fly ash, 25-30 parts of nano particles, 15-25 parts of organic fibers, 15-20 parts of dimethyl silicone, 10-15 parts of aids, 5-10 parts of pigments and 120-150 parts of water. The waterproof material disclosed by the invention has excellent waterproof, anti-permeability and antibacterial and anti-mold properties, the raw materials are environmental-friendly and high in affinity, water leakage in the toilet can be effectively prevented, and the waterproof material is difficult to age.

The invention discloses an extraction system and method for separating magnesium and extracting lithium from magnesium containing brine with a secondary amide / tertiary amide complex solvent and application of the extraction method. The extraction system contains secondary amide and tertiary amide, and each of the secondary amide and the tertiary amide is composed of a single compound or a mixtureof two or more compounds. The total number of carbon atoms in a molecule of the secondary amide ranges from 12 to 18, the total number of carbon atoms in a molecule of the tertiary amide ranges from 18 to 32, and the solidifying point of the extraction system is lower than 0 DEG C. Single-stage or multi-stage counter-current extraction is carried out under the condition that the volume ratio of anorganic phase to a brine phase is (1-10):1, the density of the brine is 1.25-1.38 g / cm<3>, and the temperature ranges from 0 DEG C to 50 DEG C; and a water phase low in magnesium-lithium ratio is obtained through reextraction, and lithium chloride, lithium carbonate and lithium hydroxide products are obtained through concentration, purification and preparation. The extraction system and method for separating magnesium and extracting lithium from the magnesium containing brine with the secondary amide / tertiary amide composite solvent and the application of the extraction method have the excellent effects that a secondary amide extraction agent is simple in molecular structure and easy to produce, and the viscosity and other physical characters of the complex solvent are improved through the tertiary amide; the multi-stage extraction rate of Li+ is high, the magnesium-lithium separation coefficient is large, water is used for reextraction, and acid-base consumption is greatly reduced; and the extraction separation technological process is short, the extraction system is small in dissolution loss, and high industrial application value is achieved.