61 results about "Aluminum citrate" patented technology

The invention relates to a high-temperature-resistant and high-salinity-resistant water-plugging profile control agent, and a preparation method and application thereof. The water-plugging profile control agent comprises polyacrylamide, a composite crosslinking agent, cyclodextrin, metaphenylene diamine and deoxidant, wherein the composite crosslinking agent consists of aldehyde, phenol and aluminum citrate; the aldehyde is one or the combination of benzaldehyde and paraformaldehyde; and the phenol is one or more of phenol, resorcinol and hydroquinone. The water-plugging profile control agent can resist the temperature of 120 DEG C, can be directly prepared by using water with mineralization degree of 150,000 mg / L, and has high crosslinking performance and long-term stability. The preparation method for the water-plugging profile control agent is simple, convenient to operate, and easy to control, and water-plugging profile control agent has a good plugging effect, and construction can be performed after the water-plugging profile control agent is directly prepared on site.

The invention discloses a preparation method of a novel alkali-free liquid accelerator. The ingredients and the proportion of the accelerator are as follows: 30-50% of aluminum sulfate, 10-20% of aluminum citrate, 2-10% of hydroxycarboxylic acid, 5-10% of ammonium hydroxide at the concentration of 20%, 0.01-0.05% of polyacrylamide and the balance of water. The preparation method comprises the following technological production steps: feeding the raw materials into a reaction kettle according to different feeding sequences, heating and uniformly mixing the raw materials at 60-80 DEG C, and cooling the mixture to obtain a colorless or light green thick liquid. The preparation method disclosed by the invention has the following advantages that due to the introduction of multi-hydroxyl functional group molecules, the coordination crosslinking of an aluminum crosslinking system and polyacrylamide molecules is promoted, a composite aluminum citrate crosslinking system with high activity is prepared, the hydration rate of cement is obviously increased, and furthermore the action effect of the accelerator is enhanced. The setting time of the cement mortar doped with the accelerator is greatly shortened, the initial setting time is shorter than 2 minutes, the final setting time is shorter than 6 minutes, the 1d (Day) compressive strength is higher than 10MPa, and the 28d compressive strength rate is higher than 140%.

The invention discloses a heat-resisting interpenetrating polymer network plural gel profile control agent. The heat-resisting interpenetrating polymer network plural gel profile control agent is characterized by being composed of the following components including (a) sodium silicate, (b) cross-linking agent which is a hydrolysable ester compound, (c) cross-linking agent which is selected from compounds of phenolic resin cross-linking agent, chromium lactic, aluminum citrate or zirconium citrate, (d) polymers which are selected from hydrolytic polyacrylamide, xanthan gum or cellulose, (e) additive I which is selected from sodium bentonite, calcium bentonite or nano silica, (f) additive II which is selected from diatomite or silicate, and (g) water. The invention also provides a preparation method of the heat-resisting interpenetrating polymer network plural gel profile control agent.

The invention relates to a preparation method of a high-temperature resisting and salt-resisting filtrate reducer for a drilling fluid, which comprises the steps of: a, dissolving a vinyl monomer in water, and regulating the pH value to 5.5-8; b, adding an initiating agent and aluminum citrate into the solution, and uniformly stirring and mixing; and c, reacting a mixed solution at a temperature of 40-100 DEG C for 1-4h, wherein the initiating agent is 0.01-0.1 percent of the vinyl monomer in mass, and the aluminum citrate is 1-3 percent of the vinyl monomer in mass. By adding the aluminum citrate solution to enable various vinyl monomers to carry out the copolymerization, the aluminum citrate is simultaneously subjected to coordination complexation with functional groups on the vinyl monomer. The invention has excellent filtration reduction property under high temperature and high salinity drilling environment. The method has simple operation and low requirement on equipment and environment, and is easy to realize the industrialization quantity production.

The invention relates to the technical field of profile-modifying and plugging agents for oil extraction and crosslinking agents thereof, in particular to a compound multivalent metallic ion crosslinking agent, a high-strength profile-modifying and plugging agent, and a production method and a use method thereof. The crosslinking agent comprises chromium citrate, zirconium lactate, aluminum citrate, organic boron, organic titanium, bisphenol A, resorcinol, methenamine and the balance of water. The invention is characterized in that the compound multivalent metallic ion crosslinking agent and the high-strength profile-modifying and plugging agent have the advantages of low cost, simple preparation method and high efficiency. The high-strength profile-modifying and plugging agent formed by the compound multivalent metallic ion crosslinking agent and polymers is suitable for plugging water for high water-cut oil layers and has strong adaptability. The high-strength profile-modifying and plugging agent can plug water in the recycle oil layer by utilizing industrial water and oil field sewage so as to effectively enhance the strength and the temperature resistance of the profile-modifying and plugging agent. The profile-modifying and plugging agent can resist a pressure of 3-15 MPa and resist a temperature of 30-150 DEG C.

The invention discloses an environment-friendly crosslinking and gelling retarding profile control agent and a preparation method thereof and belongs to the field of enhanced oil recovery technologies for oilfields. The profile control agent comprises a primary agent, i.e. hydrophobic association, a crosslinking agent, i.e. aluminum citrate, an antioxidant, i.e. sodium sulfite, and a retarding agent, i.e. sodium malate, and contains all the ingredients in percentage by weight: 0.1-0.4% of hydrophobic association, 0.01-0.02% of aluminum citrate, 0.015-0.025% of sodium sulfite, 0.005-0.020% of sodium malate and the balance of water. The profile control agent disclosed by the invention has the characteristics that the profile control agent is environment-friendly and is free of damage / injury to environments / human bodies; the crosslinking is retarded, and the gelling time is prolonged, thereby being beneficial to high-dose injection and deep profile control; the plugging rate is high; and the profile control agent has certain temperature-resistant and salt-tolerant performance and scouring resistance. The profile control agent can be used for adjusting a water absorption profile of a water-flood well and improving the water-flood development effect of oilfields.

The liquid film type microcapsule deep water blocking agent consists of water glass 5-30 wt%, formaldehyde as activator 1-10 wt%, coating agent 0.1-2.0 wt%, aluminum citrate as chelating agent 0.3-5.0 wt%, coagulant aid 0.01-0.14 wt% and water for the rest. It is superior to common water blocking agent, and has long setting time, high setting strength, controllable gel temperature and simple construction process.

The invention discloses a method for removing aluminum from rare earth material solution by organic acid complexation and solid-phase adsorption, which includes such steps as chelating reaction between citrate radical and aluminum ions in the rare earth material solution, adsorbing aluminum citrate by utilizing porous characteristics of porous polyethylene styrene resin and activated carbon, fixing aluminum ions on the surface of an adsorbent, and removing aluminum from the rare earth material solution. The removal rate of aluminum ions is 80% or above and the loss rate of rare earth is no more than 5%. Compared with other existing technologies, the existing method has low requirements on equipment, is easy to operate, and avoids the problem that aluminum hydroxide flocculent precipitationis difficult to filter, and the existing adsorbent material can be recycled, thus reducing the production cost. The invention provides an extremely effective, economical and practical way for removing aluminum from the rare earth material solution.

The present invention relates to one kind of intramolecular Al3+ cross-linked polymer gel and its preparation process. The gel cross-linking reaction happens mainly between the branch chains inside the identical polymer molecule to form í‹localíŒ netted molecular configuration. The polymer gel has basically unchanged viscosity before and after the gel is formed, and can flow in porous medium with flow resistance obviously greater than that of polymer solution in the same viscosity and residual resistance coefficient greater than the resistance coefficient. The polymer gel features consists of partially hydrolyzed polyacrylamide 0.04-0.08 wt%, aluminum citrate 0.01-0.04 wt%, and NaCl or KCl mineralization degree regulator 0.05-1.0 wt% except oil field sewage. The polymer gel has excellent profile modifying characteristic.

The invention provides a solid aluminum citrate cross-linking agent, and a preparation method and application thereof. The preparation method comprises a step of reacting citric acid with aluminum polychlorid so as to obtain the solid aluminum citrate cross-linking agent. In the preparation method, aluminum polychlorid is used as an aluminum source for reaction with citric acid; as aluminum polychlorid reacts with citric acid, the solid aluminum citrate cross-linking agent in a solid state can be directly obtained and the solid state is like the state of wet clay, so the solid aluminum citrate cross-linking agent does not have fluidity; and thus, difficulties in transportation and storage of the solid aluminum citrate cross-linking agent are reduced, and increase of procedures and cost in later drying treatment is avoided. Moreover, the solid aluminum citrate cross-linking agent prepared by using the method has aluminum ion content of 3 to 8.5%, which is beneficial for reduction in the usage amount of the cross-linking agent in usage. In addition, the cross-linking agent crosslinks with HPAM to form gel with viscosity of 12000 mpa.s, which is beneficial for improving the profile control and water plugging effect of an oil field.

The invention discloses an aluminum citrate water-plugging cross-linking agent for oil extraction. The aluminum citrate water-plugging cross-linking agent is prepared by the following specific steps: (1) with sodium metaaluminate and citric acid as raw materials, dissolving the citric acid into water, and preparing a 50% citric acid aqueous solution; (2) heating the prepared citric acid aqueous solution to 60-80 DEG C, slowly adding sodium metaaluminate solid under agitation, keeping the solution clear and transparent, and forming an aluminum citrate complex; and (3) adding stronger ammonia water to the aluminum citrate complex obtained from the step (2), adjusting the pH value of the solution to 6.0-8.0, and filtering out insoluble substances so as to obtain the aluminum citrate water-plugging cross-linking agent of which the content of aluminum ions is 30-40g / L. The aluminum citrate water-plugging cross-linking agent has the beneficial effects that the content of the aluminum ions of the aluminum citrate water-plugging cross-linking agent obtained by adopting the method can reach over 30g / L under the environment that the pH value is 6.0-8.0; the content of aluminum is high; and the aluminum citrate water-plugging cross-linking agent is small in corrosivity on equipment, does not contain anions, such as sulfate ions and nitrate ions, which are easy to scale, and is suitable for being crosslinked with polyacrylamide to form a profile control agent.

This invention relates to a method for producing aluminum citrate from kaolin by acid dissolution and crystallization. The method comprises: mechanically crushing kaolin, pressing into block, torrefying in a high temperature furnace so that kaolinite in kaolin is dehydrated to obtain metakoalin with reactive activity, torrefying, adding into citric acid solution, stirring, leaching, filtering, precipitating white aluminum citrate crystal from the filtrate, separating, and crystallizing to obtain aluminum citrate product. The method utilizes kaolin instead of aluminum salt as the raw material, and has such advantages as abundant raw material, and simple process.

Relating to the field of oilfield applied chemistry, the invention provides a low permeability pore type oil reservoir double-slug deep profile control agent and a use method thereof. The profile control agent provided by the invention is injected into a low permeability pore type oil reservoir, in a pre-slug, sodium silicate, partially hydrolyzed polyacrylamide, sodium hexametaphosphate, sodium sulfite, salicylic acid and aluminum citrate are mixed, so that the pre-slug can have the characteristics of low viscosity, strong fluidity and anti-shear capacity, and can block a high permeability pore in the oil reservoir. In a post-slug, a compounded polymer is mixed with a chromium aluminum ion crosslinking agent, so that the post-slug can have the characteristics of low viscosity and strong fluidity, after effective blockage by the pre-slug, the post-slug is injected into the oil reservoir to implement profile control and flooding so as to reduce the residual oil content and increase the water absorption index of the oil reservoir. The double-slug combination way can improve the nonhomogeneity of the oil reservoir, increase the subsequent waterflooding water flooding sweep coefficient, suppress the formation of a low permeability pore type oil reservoir dead oil area, and improve the disadvantages of low recovery rate, poor economic benefits and the like for low permeability pore type oil reservoirs in traditional oil production methods.

The invention belongs to the field of high molecular materials and particularly relates to a polyphenyl ether modified polyphenylene sulfide material for an automotive plastic part. The material is prepared from the following raw materials in parts by weight: 100 parts of polyphenylene sulfide, 14-18 parts of polyphenyl ether, 4-5 parts of carbodiimide, 3-5 parts of aluminum citrate, 1-2 parts of silane coupling agent KH-550, 1-2 parts of di(2-Ethylhexyl)-4,5-epoxycyclohexane-1,2-dicarboxylate, 2-3 parts of chitosan, 12-15 parts of white carbon black, 1-2 parts of silicon carbide and 12-15 parts of assistant. The material provided by the invention combines the advantages of the raw materials such as polyphenylene sulfide and polyphenyl ether and improves the performances of conventional nylon materials, so that the material has good processing and mechanical performances. The prepared material is firm and wear-resistant, high-temperature resistant and waterproof, good in electric insulating performance, flame-retardant and safe and reliable to use, and can be widely applied to preparing various automotive plastic parts.

The present invention is a kind of preparation method of oil well cement filtrate reducer, comprising the following steps: (1) dissolving lignin in deionized water, adding redox initiator ferrous ammonium sulfate and hydrogen peroxide, feeding nitrogen to initiate; ( 2) Weigh two anionic monomers of acrylic acid and sodium p-vinylbenzenesulfonate, dissolve them in water and adjust the pH to 6-7, add potassium persulfate as an initiator, and feed nitrogen to initiate; (3) Mix the lignin monomer and two kinds of anionic monomers, add aluminum citrate cross-linking agent and continuously feed nitrogen to carry out graft modification; (4) after the reaction is completely finished, add absolute ethanol, demulsify and filter, A solid product was obtained. In the present invention, lignin macromolecules and modified monomers are respectively initiated to increase the grafting rate of the polymerization reaction, and aluminum citrate is used as a crosslinking agent, which is stable and conducive to the production of high-quality products. The method of the present invention is simple and can For a variety of grafting monomers, the feasibility is very high.

The invention belongs to the technical field of a building material, and particularly relates to a high-intensity solubilizing liquid accelerator and a preparation method thereof, wherein the liquid accelerator at least comprises the following preparation raw materials in parts by weight: 30 to 40 parts of aluminum sulfate, 5 to 10 parts of aluminum citrate, 2 to 8 parts of hydroxyethyl cellulose,1 to 10 parts of pH regulators, 5 to 15 parts of complexing enhancers, 0.5 to 3 parts of stabilizing agents and the balance of water. Through the introduction of hydroxyethyl cellulose for synthesizing the liquid accelerator; through the combination of the complexing enhancers, stabilizing agents and the hydroxyethyl cellulose in the solution, a crosslinked reticular structure is formed; the goodsolubilizing effect can be achieved; the product concentration is as high as 80 percent; phenomena of layering and precipitation separation cannot occur; the product dissolution effect is good; the transportation cost of the liquid accelerator can be reduced.

The invention discloses an organic / inorganic composite colloidal dispersion gel and a preparation method thereof. The colloidal dispersion gel comprises water, an acrylamide polymer, an inorganic cross-linking agent and an organic cross-linking agent; in the colloidal dispersion gel, the massic volume concentrations of the acrylamide polymer, the inorganic cross-linking agent and the organic cross-linking agent are 1000 to 2000 mg / L, 10 to 130 mg / L and 50 to 1000 mg / L, respectively; the inorganic cross-linking agent is aluminum citrate, and the organic cross-linking agent is tetramethylol acetylenediurea. The preparation method for the composite colloidal dispersion gel comprises the following steps: adding the acrylamide polymer into the water so as to obtain a polymer solution and regulating and controlling the pH value of the polymer solution to be 6.0 to 7.5; and adding the inorganic cross-linking agent and the organic cross-linking agent into the polymer solution and carrying out aging so as to obtain the composite colloidal dispersion gel. The organic / inorganic composite colloidal dispersion gel provided by the invention has a wide operating temperature range and can effectively improve the viscosity of the acrylamide polymer in a range of 35 to 85 DEG C. A crosslinking system is nontoxic and poses little influence to the environment.

The invention discloses a leather tanning agent and a preparation method thereof, and belongs to the technical field of leather machining. The leather tanning agent comprises, by weight, 30-40 parts of polyetherdiolbranchedacrylicresin, 15-20 parts of modified grapheneoxide, 3-5 parts of aluminum citrate, 1-3 parts of sodium hexametaphosphate and 50-60 parts of water. The leather tanning agent is combined by adopting specific components, especially polyetherdiolbranchedacrylicresin, flexiblebranchedpolyetherdiol is led into polyacrylic acid to improve the selecting and filling property of acrylicresin, the sense of water and elasticity of leather are improved, then polyetherdiolbranchedacrylicresin, an aluminium tanning agent, modified grapheneoxide and the like are matched and used, the leather softness is improved, meanwhile, the leather grain flat is fine and smooth, the leather contraction temperature can be improved, the leather tanning agent is suitable for tanning of various leather, and the good application prospect is achieved.

The invention discloses a profile controlling and flooding agent for weak gel complex clay and a preparation method thereof, and belongs to the technical field of oil field water injection well profile controlling and flooding. The profile controlling and flooding comprises the following components in parts by weight: 0.1 to 0.4 part of clay, 0.03 to 0.08 part of polyacrylamide, 0.001 to 0.007 part of an alkaline modifier, 0.04 to 0.17 part of a cross-linking agent, and 100 parts of clear water, wherein the cross-linking agent is selected from at least one in chromic acetate, aluminum citrate,glyoxal and chromium lactate. The profile controlling and flooding agent has the characteristics that the clay and polyacrylamide solution are not laminated, the profile controlling and flooding agent can be used for oil well deep layer profile controlling and flooding, long action time and high profile controlling and flooding strength.

The invention discloses an inorganic gel profile control agent suitable for thermal oil recovery and a use method thereof, and relates to the chemical field of oil field application. The inorganic gel profile control agent is prepared from gel emulsion and inorganic matter formation sealant, wherein the mass ratio of weak gel emulsion is 85-90%, and the mass ratio of the inorganic matter formation sealant is 10-15%; the weak gel emulsion is prepared from parts of HPAM (hydrolytic polyacrylamide) with a relative molecular weight of 1000*10<4>, an organic chromium system, aluminum citrate, sodium fluosilicate and prepared water, and the inorganic matter formation sealant is montmorillonite. The use method comprises the following steps: combining with oil field production data to design a profile control agent injection amount; after the profile control agent finishes being prepared, injecting into a stratum via an oil field injection well; after a preset range is achieved, standing for 2-3 days to cure the profile control agent; after curing, carrying out a subsequent injection production operation. According to the profile control agent, the high-temperature stratum can be effectively sealed, the profile control agent can be applied to thermal force oil extraction ways including in-situ combustion, steam flooding, SAGD (Steam Assisted Gravity Drainage), mixed-phase thermal fluid flooding and the like; before the weak gel emulsion is cured, viscosity is low, and the weak gel emulsion can be easily injected, can be suitable for a mineralization degree below 100000mg, is cheap and easy to obtain.

The invention relates to a method for preparing butyl butyrate by directly converting n-butyraldehyde. According to the method, n-butyraldehyde is used as a raw material, one or more than two of organic dibasic acid aluminum or organic tribasic acid aluminum such as aluminum oxalate, aluminum citrate, aluminum tartrate, aluminum malate, aluminum adipate, aluminum heptanedioate, aluminum dodecanedioate and the like are used as catalysts, the use amount of the catalyst is 0.2-1.0% of the mass of the n-butyraldehyde, the reaction temperature is 0-20 DEG C, the reaction time is 0.5-2 hours, and the n-butyraldehyde conversion rate and the butyl butyrate selectivity can reach more than 99%. The method has the advantages of short route, good atom economy, mild reaction conditions, catalyst recyclability, high raw material conversion rate, high product selectivity and the like.

The invention relates to a method for synthesizing an aluminum citrate cross-linking agent in a low carbon solvent. (1) the weight part proportions of chemical raw materials are as follows: 100-140 parts of methanol, 40-60 parts of ethanol, 40-100 parts of citric acid, 30-60 parts of aluminium chloride hexahydrate, 10-20 parts of sodium hydroxide and 20-30 parts of water. (2) the method comprises the following chemical reaction process steps of: firstly mixing methanol and ethanol according to the proportion under a normal pressure; adding citric acid to the above mixture to make citric acid dissolved completely; adding aluminium chloride hexahydrate under stirring; heating to a temperature of 40-80 DEG C; reacting for 4 hours; dropwise adding a sodium hydroxide solution slowly to adjust a pH value to 5.5-8.5; finally, adding a residual component of water, stirring uniformly, and thus the aluminum citrate cross-linking agent is obtained. The aluminum citrate cross-linking agent synthesized by the method has stable gel-forming properties and controllable gel-forming time, and has no sulfate ions and nitrate ions. The synthetic process is gent and easy to operate, has no generation of industrial waste materials, and is economic and environment-friendly.

The invention relates to the technical field of profile-modifying and plugging agents for oil extraction and crosslinking agents thereof, in particular to a compound multivalent metallic ion crosslinking agent, a high-strength profile-modifying and plugging agent, and a production method and a use method thereof. The crosslinking agent comprises chromium citrate, zirconium lactate, aluminum citrate, organic boron, organic titanium, bisphenol A, resorcinol, methenamine and the balance of water. The invention is characterized in that the compound multivalent metallic ion crosslinking agent and the high-strength profile-modifying and plugging agent have the advantages of low cost, simple preparation method and high efficiency. The high-strength profile-modifying and plugging agent formed by the compound multivalent metallic ion crosslinking agent and polymers is suitable for plugging water for high water-cut oil layers and has strong adaptability. The high-strength profile-modifying and plugging agent can plug water in the recycle oil layer by utilizing industrial water and oil field sewage so as to effectively enhance the strength and the temperature resistance of the profile-modifying and plugging agent. The profile-modifying and plugging agent can resist a pressure of 3-15 MPa and resist a temperature of 30-150 DEG C.

The invention discloses an application of aluminum citrate to hydrangea macrophylla color adjustment and control, and belongs to the technical field of flower and plant preservation and flower color regulators. According to the application, hydrangea macrophylla cut flowers are placed into 0.55-1.1g / L aluminum citrate flower color regulators, red or pink hydrangea macrophylla cut flowers can turnpurple and then turn blue within 2-4 days at a vase phase, so that hydrangea macrophylla color (blue) is adjusted and controlled in the field in the hydrangea macrophylla planting process, labor and production costs are greatly saved, controllability of the quality of cut flower products is improved by enterprises, and ornamental values, interestingness and additional values of fresh hydrangea macrophylla cut flowers are enhanced.

The invention provides a nano titanium dioxide-doped water-based paint with a sterilization function and a production process thereof. The water-based paint is prepared from the following raw materials in percentage by weight: 20-32% of water-based acrylate emulsion, 1-3% of iron-doped nano titanium dioxide, 0.5-1.5% of cerium-doped nano titanium dioxide, 2-5% of silver-loaded tourmaline powder, 6-12% of rectorite micro powder, 0.5-0.8% of aluminum citrate, 0.2-0.5% of silane coupling agent, 6-10% of alcohol solvent and the balance of water. The coating produced by the method is smooth in appearance, high in adhesive force and high in strength, and has excellent air purification performance and antibacterial performance.

The invention relates to an environment-friendly high temperature and salt resistant calcium modified natural polymer fluid loss reducer. Its technical solution is: it is made of the following components, by mass percentage: 20%-30% of modified starch, 3%-8% of partially hydrolyzed polyacrylamide, 3%-5% of aluminum citrate, and 10% of superfine calcium carbonate %‑20%, the balance is water. Beneficial effects are: the present invention is aimed at the downhole complex situation of high-temperature deep well drilling, especially the brine layer, salt rock layer, salt-gypsum layer, and gypsum-mud layer. High temperature and salt-resistant calcium fluid loss reducer is the key to improving the wall-building ability of drilling fluid; the product prepared by the present invention has outstanding fluid loss reducing effect, strong wall-building, temperature resistance up to 150°C and above, salt resistance to saturation, Resistant to 0.5% CaCl 2 . The product has good compatibility with other treatment agents, is non-toxic and environmentally friendly, and can also be used as a protection material for drilling fluid oil and gas layers.

The invention discloses an alkali-free quick-setting agent. The composition and proportion of the quick-setting agent are: 30-50% of aluminum sulfate, 10-20% of aluminum citrate, 2-10% of hydroxycarboxylic acid, 20% The concentration of ammonia water is 5-10%, polyacrylamide is 0.01-0.05%, and the rest is water. The production process is that the above raw materials are put into the reaction kettle according to different feeding orders, heated at 60-80°C, stirred evenly, and form a colorless or light green viscous liquid after cooling. The advantage of the present invention is that the introduction of multi-hydroxyl functional group molecules promotes the coordination crosslinking of the aluminum crosslinking system and polyacrylamide molecules, and prepares a high-activity composite aluminum citrate crosslinking system, which significantly improves the cement's strength. Hydration rate, thus enhancing the effect of accelerator. The setting time of the cement mortar mixed with this accelerator is greatly shortened, the initial setting is less than 2 minutes, the final setting is less than 6 minutes, and the 1d compressive strength exceeds 10MPa, and the 28d compressive strength ratio is greater than 140%.

The invention belongs to the technical field of coal mine fire prevention and extinguishment, and discloses a fire preventing and extinguishing gel preparation method and a coal mine fire preventing and extinguishing method. The fire preventing and extinguishing gel is prepared from, by mass, 1%-2% of carboxymethyl cellulose, 4%-5% of a cross-linking agent, 4%-5% of sodium bicarbonate, 4%-5% of a water glass diluted solution, 0.1%-0.3% of a pH regulator and water. The preparation method comprises the following steps: dissolving carboxymethyl cellulose in distilled water, heating and fully stirring, then adding aluminum citrate into a solution, introducing nitrogen for protection, and reacting to obtain a first solution; raising the temperature, continuously adding glucolactone into the first solution, and continuously stirring and reacting to obtain a second solution; adding sodium bicarbonate into the second solution, uniformly stirring, adding the pH regulator, and adjusting to obtain a third solution; dissolving water glass in distilled water, mixing, dropwise adding into the third solution, and reacting to obtain a final product. The coal storage time is prolonged, and the safety production efficiency of a coal mine is improved.

The invention discloses a flocculant used in the process of removing impurities of steviol glycosides. The raw materials include: 10-20 parts of modified chitosan, 15-25 parts of modified lignin, and 30-40 parts of polyferric sulfate , 25-35 parts of aluminum citrate, 10-15 parts of magnesium sulfate, 20-30 parts of polysilicate iron, 3-5 parts of porous perlite powder, 4-6 parts of zeolite powder; wherein the preparation method of modified chitosan For: carboxymethyl chitosan is added in aqueous sodium hydroxide solution, heat up, after insulation, dropwise add 3-chloro-2-hydroxypropyltrimethylammonium chloride aqueous solution, then continue insulation, then adjust to neutrality to obtain The first material: add the first material to ethanol, filter, and dry to obtain the second material; add the second material to distilled water and stir evenly, then heat in a water bath, then add acrylamide and initiator dropwise in sequence, and keep warm to obtain the third material ; Add the third material to acetone, filter, and dry to obtain modified chitosan.