CN112251057B

CN112251057B - Indoor thick steel structure fireproof coating and preparation method thereof

Info

Publication number: CN112251057B
Application number: CN202011008478.0A
Authority: CN
Inventors: 张印民; 张永锋; 刘斌; 李炜; 王卫江
Original assignee: Inner Mongolia Yichen Environment Material Co ltd; Shenzhen Yichen Environmental Technology Co ltd; Inner Mongolia University of Technology
Current assignee: Inner Mongolia University of Technology
Priority date: 2020-09-23
Filing date: 2020-09-23
Publication date: 2022-01-21
Anticipated expiration: 2040-09-23
Also published as: CN112251057A

Abstract

The invention provides an indoor thick steel structure fireproof coating, which relates to the technical field of fireproof coatings and comprises the following components in parts by weight: 5-20 parts of fly ash hollow microspheres, 20-60 parts of sodium silicate solution, 5-10 parts of expanded perlite, 1-3 parts of aluminum silicate fibers, 5-15 parts of aluminum hydroxide, 5-15 parts of magnesium hydroxide, 1-3 parts of porous active silicon materials, 5-15 parts of titanium dioxide, 10-20 parts of pure acrylic emulsion, 0.2-1 part of dispersing agent, 0.2-1 part of defoaming agent, 0.2-1 part of plasticizer, 0.2-1 part of flatting agent, 0.2-1.5 parts of film forming assistant and 20-60 parts of water. According to the invention, the small-particle-size hollow microspheres are used as the filler, and the sodium silicate solution prepared by screening the rest large-particle-size hollow microspheres is used as the binder of the coating, so that the fireproof coating has excellent physical and chemical properties and heat insulation and flame retardance under the condition of not using cement while resource recycling is realized.

Description

Indoor thick steel structure fireproof coating and preparation method thereof

Technical Field

The invention relates to the technical field of coatings, in particular to an indoor thick steel structure fireproof coating and a preparation method thereof.

Background

The steel structure building has great advantages in the aspects of stability, rigidity, seismic performance and the like, and is widely applied to modern buildings in various fields. However, the steel has the characteristics of poor fireproof and corrosion resistance, on one hand, the steel is a good heat conductor, the heat conductivity coefficient is about 40 times of that of the traditional masonry, and the steel has large thermal expansion coefficient and is easy to deform; on the other hand, the yield stress, the elastic modulus and other mechanical parameters of the steel are in a negative correlation with the temperature, the steel basically loses the bearing capacity when reaching the critical temperature (540 ℃) along with the rise of the temperature, and the critical temperature can be reached within about 5min according to a fire standard temperature rise curve (see figure 2), so that accidents such as building collapse are caused. Therefore, steel members that do not provide fire protection to the steel structure do not meet the fire resistance requirements for buildings in the event of a fire. Furthermore, in order to improve the fire resistance level of the steel structure, it is necessary to protect the steel structure from fire. The steel structure fireproof coating is commonly used in steel structure fireproof protection in China, and the protection method has the characteristics of simple and convenient construction, excellent fireproof performance and no limitation by the shape of a steel member.

The steel structure fireproof paint can be divided into an ultra-thin type, a thin type and a thick type according to the fireproof mechanism. The fire-retardant coating for the thick steel structure mainly comprises inorganic components, belongs to a flame-retardant or non-combustible substance and can play a role in flame shielding, the light components in the components can greatly reduce the heat conductivity coefficient of the coating and delay the speed of transferring heat to a base layer, the flame-retardant components in the components are decomposed in a large amount to absorb heat in a fire receiving process, water vapor and the like are released, surrounding air is diluted in a certain range, the flame combustion process is delayed, decomposed solid residues form a glaze layer which is compact in structure and good in heat insulation, and heat can be effectively prevented from being transferred to the bottom of a base material.

At present, many patents are available for fire-retardant coatings for thick steel structures, wherein cement is used as a binder to prepare the coatings, and for example, Sun Jiafu (patent publication No. CN106904908A) uses a component A formed by mixing portland cement, expanded vermiculite, expanded perlite, reinforcing fibers and a sound-absorbing auxiliary agent and a component B formed by mixing ethylene-vinyl acetate copolymer emulsion, organosilicon modified styrene-acrylic emulsion and water as raw materials to prepare an indoor fire-retardant coating for thick steel structures, which has good fire resistance and heat insulation, good weather resistance, firm bonding and good crack resistance. Wangjiaxin et al (patent publication No. CN106699052A) designed a thick steel structure fire-retardant coating prepared from cement binder (1-50%), fly ash, fire-resistant clay, calcium carbonate, silica aerogel, expanded perlite, flame retardant, fiber and auxiliary agent, and can greatly improve the heat-insulating and fire-retardant capability of the steel structure fire-retardant coating. Zhengyufeng et al (patent publication No. CN106280591A) designed thick-coating type steel structure fire-retardant coating with 42:5R portland cement and polyethylene glycol 2000 as composite binder, and aluminum silicate fiber inorganic material as anti-cracking heat-insulating filler, and has the characteristics of strong binding strength, good acid and alkali resistance and excellent fire-retardant property. In conclusion, the cement-based binder is used in a large amount, so that the gelation and hardening processes of the cement are influenced to crack possibly due to incomplete or inhibited hydration and hydrolysis of the cement, the coating is accelerated to age, and flame penetrates through gaps when the coating is fired, so that the steel member is rapidly heated and loses bearing capacity; in addition, the use of a large amount of cement-based binder needs more organic emulsion and organic auxiliary agent to regulate and control physical and chemical properties, and the smoke generation amount of the fireproof coating is increased to a certain extent when the fireproof coating is on fire. Therefore, there is a need for improvement of the fire-retardant coating formula, and the fire-retardant coating for the indoor thick steel structure, which uses little or even no cement as a binder, can effectively avoid cracking during initial drying, and has good physical and chemical properties, heat insulation and flame retardance.

Disclosure of Invention

The invention aims to provide an indoor thick steel structure fireproof coating and a preparation method thereof, which can completely avoid cement as a binder, effectively avoid cracking during initial drying, and enable the coating to have excellent physical and chemical properties, heat insulation and flame retardance.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides an indoor thick steel structure fireproof coating which comprises the following components in parts by mass:

5-20 parts of fly ash hollow microspheres, 20-60 parts of sodium silicate solution, 5-10 parts of expanded perlite, 1-3 parts of aluminum silicate fibers, 5-15 parts of aluminum hydroxide, 5-15 parts of magnesium hydroxide, 1-3 parts of porous active silicon materials, 5-15 parts of titanium dioxide, 10-20 parts of pure acrylic emulsion, 0.2-1 part of dispersing agent, 0.2-1 part of defoaming agent, 0.2-1 part of plasticizer, 0.2-1 part of flatting agent, 0.2-1.5 parts of film forming assistant and 20-60 parts of water.

Preferably, the particle size of the fly ash cenosphere is less than or equal to 180 mu m.

Preferably, the modulus of the sodium silicate solution is 1.6-2.2.

Preferably, the preparation of the sodium silicate solution comprises the following steps:

(1) mixing the compound alkali and the fly ash hollow micro-beads, and roasting to obtain nepheline; the compound alkali comprises sodium carbonate and sodium hydroxide;

(2) acid leaching the nepheline obtained in the step (1) to obtain acid residue and acid leaching filtrate;

(3) and (3) carrying out alkali dissolution on the acid residue obtained in the step (2), and then extracting a mold to obtain a sodium silicate solution.

Preferably, the mass ratio of sodium carbonate to sodium hydroxide in the compound alkali in the step (1) is (0.5-2.5): 1.

preferably, the mass ratio of the fly ash hollow microspheres to the compound alkali in the step (1) is (0.5-3): 1.

preferably, the roasting temperature in the step (1) is 700-1000 ℃, and the roasting time is 1-5 h.

Preferably, the preparation of the aluminum hydroxide comprises the following steps:

(a) taking the acid leaching filtrate obtained in the step (2) in the technical scheme, adjusting the pH value to 11-13, and filtering to obtain an alkaline solution;

(b) and (b) introducing excessive carbon dioxide into the alkaline solution in the step (a) to obtain a suspension, and removing the solvent to obtain the aluminum hydroxide.

Preferably, the titanium dioxide is anatase titanium dioxide.

The invention also provides a preparation method of the indoor thick-type steel structure fireproof coating, which comprises the following steps:

mixing magnesium hydroxide, aluminum hydroxide, titanium dioxide, porous active silicon materials and aluminum silicate fibers, and then mixing with a sodium silicate solution, water and a dispersing agent to obtain slurry A;

II, mixing the slurry A obtained in the step I with a pure acrylic emulsion, a defoaming agent, a plasticizer, a flatting agent and a film-forming assistant to obtain slurry B;

and III, mixing the slurry B in the step II with the fly ash hollow microspheres and the expanded perlite to obtain the coating.

The invention provides an indoor thick steel structure fireproof coating which comprises the following components in parts by weight: 5-20 parts of fly ash hollow microspheres, 20-60 parts of sodium silicate solution, 5-10 parts of expanded perlite, 1-3 parts of aluminum silicate fibers, 5-15 parts of aluminum hydroxide, 5-15 parts of magnesium hydroxide, 1-3 parts of porous active silicon materials, 5-15 parts of titanium dioxide, 10-20 parts of pure acrylic emulsion, 0.2-1 part of dispersing agent, 0.2-1 part of defoaming agent, 0.2-1 part of plasticizer, 0.2-1 part of flatting agent, 0.2-1.5 parts of film forming assistant and 20-60 parts of water. The fireproof coating for the indoor thick steel structure provided by the invention adopts the fly ash hollow microspheres and the expanded perlite as the heat-insulating filler of the fireproof coating, and the characteristics of high chemical stability and low heat conductivity coefficient of the material are utilized, so that the fireproof coating has good flame retardance; the sodium silicate solution is used as a binder instead of cement, so that cracking during initial drying can be effectively avoided, the use of organic emulsion and auxiliaries is reduced, and the problem of large smoke generation during fire is avoided; aluminum hydroxide and magnesium hydroxide are used as flame retardants, and can absorb a large amount of heat when heated and decompose to form a hard enamel layer, so that a hole framework of the fireproof coating when fired is established; under the condition of adding a small amount of dispersing agent, defoaming agent, plasticizer, flatting agent and film-forming additive, the slurry of the coating is ensured to be in a uniform thick fluid state without agglomeration, and the coating has good slurry hanging capability and film-forming capability during coating, and can form a smooth thick blocking layer and avoid falling off; and alsoThe porous active silicon material is added, the porous active silicon material can be used as a framework of the coating, and meanwhile, the aluminum silicate fiber is added, so that the cracking of the coating is avoided, and the coating has excellent mechanical properties. The results of the examples show that the samples of the examples can be dried in a short time of not more than 2.5h, meet the requirement of cracking resistance specified in GB14907-2002 in the early stage of drying, the bonding strength can reach 0.15-0.26 MPa, the compressive strength can reach 0.8-1.1 MPa, and the dry density is 687-801 kg/m³When the thickness of the coating is 25-28.4 mm, the back temperature end point temperature of the sample after 3h burning is 166.5-175.1 ℃, the water resistance and the cold and heat cycle resistance meet the requirements of GB14907-2002, and the coating does not have the conditions of layer forming, foaming, cracking and falling off.

In addition, the sodium silicate solution and the aluminum hydroxide in the fireproof coating are prepared by screening the residual large-particle-size fly ash cenospheres (larger than 180 mu m), and the small-particle-size fly ash cenospheres (smaller than or equal to 180 mu m) are used as heat-insulating fillers of the fireproof coating, so that the full utilization of the cenospheres in the fireproof coating is realized, and the method has important significance for the resource utilization of the fly ash cenospheres.

Drawings

FIG. 1 is a schematic diagram of a fire resistance test device of a fire retardant coating in an embodiment of the invention, wherein 1 is a bracket, 2 is an alcohol burner, 3 is a steel plate sample coated with a coating, 4 is heat preservation cotton, 5 is a double-needle surface thermocouple, 6 is a K-type thermocouple, and 7 is a digital display instrument;

FIG. 2 is a graph showing the temperature rise of the apparatus for testing the fire resistance of the fire retardant coating in the embodiment of the present invention.

Detailed Description

The invention provides an indoor thick steel structure fireproof coating which comprises the following components in parts by weight: 5-20 parts of fly ash hollow microspheres, 20-60 parts of sodium silicate solution, 5-10 parts of expanded perlite, 1-3 parts of aluminum silicate fibers, 5-15 parts of aluminum hydroxide, 5-15 parts of magnesium hydroxide, 1-3 parts of porous active silicon materials, 5-15 parts of titanium dioxide, 10-20 parts of pure acrylic emulsion, 0.2-1 part of dispersing agent, 0.2-1 part of defoaming agent, 0.2-1 part of plasticizer, 0.2-1 part of flatting agent, 0.2-1.5 parts of film forming assistant and 20-60 parts of water.

The raw materials of the indoor thick steel structure fireproof coating comprise, by mass, 5-20 parts of fly ash cenospheres, preferably 8-15 parts of fly ash cenospheres, and more preferably 11-12 parts of fly ash cenospheres. In the invention, the particle size of the fly ash cenosphere is preferably less than or equal to 180 mu m, and more preferably less than or equal to 150 mu m. The fly ash cenospheres are preferably screened, the obtained small-particle-size cenospheres with the particle size of less than or equal to 180 mu m are used as a filler, and the fly ash cenospheres with the particle size of more than 180 mu m are used as raw materials to prepare the sodium silicate solution. In the invention, the fly ash cenosphere has the characteristics of high chemical stability, low heat conductivity coefficient and the like, and can ensure that the fireproof coating has good heat insulation and flame retardant properties.

The raw materials of the indoor thick steel structure fireproof coating provided by the invention comprise 20-60 parts of sodium silicate solution, preferably 25-55 parts, and more preferably 33-45 parts by mass of fly ash hollow microspheres. In the invention, the modulus of the sodium silicate solution is preferably 1.6-2.2, more preferably 1.9-2.15, and most preferably 2.0-2.1.

In the present invention, the preparation of the sodium silicate solution preferably comprises the steps of:

According to the invention, preferably, the compound alkali and the fly ash hollow micro-beads are mixed and then roasted to obtain the nepheline.

In the invention, before mixing the compound alkali and the fly ash cenospheres, the fly ash cenospheres is preferably sieved by a standard sieve with 80 meshes, and the cenospheres (the particle size is more than 180 mu m) which are not sieved are crushed. The crushing is preferably ball milling; the rotation speed of the ball milling is preferably 300-500 r/min, and more preferably 350-400 r/min; the ball milling time is preferably 4-8 h, and more preferably 5-6 h. The particle size of the pulverized fuel ash hollow microspheres after ball milling is preferably 16.2-19.7 microns. In the invention, the specific surface area of the particle size of the fly ash cenosphere is large in the range, and the reactivity is higher.

The source of the fly ash cenospheres is not particularly limited in the present invention, and commercially available products well known to those skilled in the art may be used. The fly ash cenospheres with small grain size less than or equal to 180 mu m is obtained by screening the fly ash cenospheres and is used as a component of the coating, and the fly ash cenospheres with the grain size of more than 180 mu m is crushed to prepare the sodium silicate solution.

In the invention, the compound alkali preferably comprises sodium carbonate and sodium hydroxide, and the mass ratio of the sodium carbonate to the sodium hydroxide in the compound alkali is preferably (0.5-2.5): 1, more preferably (0.8 to 2.3): 1.

in the invention, the mass ratio of the fly ash cenospheres for preparing the sodium silicate solution to the compound alkali is preferably (0.5-3): 1, more preferably (1.5 to 2.5): 1.

in the invention, the mixing of the compound alkali and the fly ash cenospheres is not particularly limited, and the compound alkali and the fly ash cenospheres can be uniformly mixed by adopting a mixing mode well known in the field.

In the invention, the roasting temperature is preferably 700-1000 ℃, and more preferably 750-900 ℃; the roasting time is preferably 1-5 h, and more preferably 1.5-4.5 h. In the present invention, the roasting equipment is preferably a muffle furnace, and the roasting environment is preferably an air environment. In the invention, the roasting can convert the silicon-aluminum element in the fly ash hollow microsphere into an aluminosilicate form which is easy to dissolve in acid, the aluminum-silicon separation is realized after acid leaching, the silicon oxide is the main component for preparing the sodium silicate solution, and the aluminum element can be further reused for preparing the aluminum hydroxide.

After nepheline is obtained, the invention preferably performs acid leaching on the nepheline to obtain acid sludge and acid leaching filtrate.

In the invention, the mass concentration of the acid used for acid leaching is 8-20%, and more preferably 12-16%; the acid used for acid leaching is preferably hydrochloric acid solution; the liquid-solid mass ratio during acid leaching is preferably (5-15): 1, more preferably (8-12): 1. in the invention, the acid leaching temperature is preferably 40-95 ℃, and more preferably 55-85 ℃; the acid leaching time is preferably 5-90 min, and more preferably 25-65 min. In the present invention, the acid leaching process allows dissolution of the calcined nepheline, formation of an acid leaching filtrate from hydrochloric acid soluble alumina in the nepheline, and formation of an acid sludge from hydrochloric acid insoluble silica, thereby allowing better separation of silicon and aluminum for the production of the sodium silicate solution and the aluminum hydroxide, respectively.

After the acid sludge is obtained, the acid sludge is preferably subjected to alkali dissolution and then is subjected to mold extraction to obtain a sodium silicate solution.

In the invention, the mass concentration of the alkali used for alkali dissolution is 5-30%, more preferably 12-25%, and the alkali used for alkali dissolution is preferably sodium hydroxide solution; the liquid-solid mass ratio in the alkali dissolution is preferably (3-25): 1, more preferably (8 to 22): 1. in the invention, the temperature of the alkali dissolution is preferably 60-160 ℃, and more preferably 80-120 ℃; the time for alkali dissolution is preferably 0.5-6 h, and more preferably 0.8-5 h. In the invention, the alkali dissolution enables the silicon oxide in the acid sludge to fully react with the alkali solution at the alkali dissolution temperature, and is more beneficial to mold lifting to form a sodium silicate solution with high viscosity and good coagulation effect.

According to the invention, the sodium silicate solution is prepared by the preparation method, so that the large-particle-size fly ash cenospheres are fully recycled, a new purpose is provided for the large-particle-size cenospheres, the resource recycling is realized, and the cost is saved; and because the fly ash hollow microspheres are rich in silicon and aluminum elements, the sodium silicate solution provided by the invention can be converted into the sodium silicate solution with strong binding power and good quick-setting effect through the preparation steps of the sodium silicate solution, so that the use of cement can be effectively replaced, and the use amount of organic emulsion and auxiliaries can be reduced, thereby avoiding the problems that the cement-based fireproof coating is easy to crack at the early drying stage and is easy to smoke when being subjected to fire.

The raw materials of the indoor thick-type steel structure fireproof coating comprise, by mass, 5-10 parts of expanded perlite, preferably 6-9 parts of expanded perlite, and more preferably 7-8 parts of expanded perlite. The source of the expanded perlite in the present invention is not particularly limited, and commercially available products well known in the art may be used. In the invention, the volume expansion multiple of the expanded perlite is preferably 10-16 times. The particle size of the expanded perlite is preferably 2-4 mm. The expanded perlite has a honeycomb-shaped enamel layer structure and has quite excellent heat insulation performance.

The raw materials of the indoor thick steel structure fireproof coating comprise, by mass, 1-3 parts of aluminum silicate fibers, preferably 1.3-2.7 parts, and more preferably 1.8-2.3 parts. The source of the alumina silicate fiber is not particularly limited in the present invention, and commercially available products well known in the art may be used. In the present invention, the length of the aluminum silicate fiber is preferably 2mm or less, more preferably 1.5mm or less. The aluminum silicate fiber can improve the strength of the coating, can bear stress in the fire process, and effectively prevents cracking.

The raw materials of the indoor thick steel structure fireproof coating comprise, by mass, 5-15 parts of aluminum hydroxide, preferably 6-13 parts of aluminum hydroxide, and more preferably 9-11 parts of aluminum hydroxide. In the present invention, the preparation of the aluminum hydroxide preferably comprises the steps of:

(a) taking acid leaching filtrate obtained in the preparation process of the sodium silicate solution, adjusting the pH value to 11-13, and filtering to obtain alkaline solution;

In the invention, preferably, the acid leaching filtrate obtained in the preparation process of the sodium silicate solution is taken, and the pH is adjusted to 11-13 to obtain an alkaline solution.

In the invention, the pH is preferably adjusted by adding an alkali solution, and the alkali solution is preferably sodium hydroxide solution; the mass concentration of the alkali solution is 15-25%, and more preferably 18-22%.

After obtaining the alkaline solution, the invention preferably introduces excessive carbon dioxide into the alkaline solution to obtain a suspension, and then removes the solvent to obtain the aluminum hydroxide.

In the invention, the speed and time of introducing the carbon dioxide are not particularly limited, and the components in the alkaline solution can be fully reacted.

In the present invention, the solvent is preferably removed after the suspension is obtained by drying; the drying temperature is preferably 100-120 ℃, and more preferably 110-120 ℃; the drying time is preferably 4-8 h, and more preferably 5-6 h.

In the invention, the preparation method of the aluminum hydroxide reuses the byproduct acid leaching filtrate in the process of preparing the sodium silicate solution, realizes resource reutilization again, reduces the pollution of waste liquid to the environment and saves the cost; in addition, the aluminum hydroxide is used as a flame retardant, so that the flame retardant can not only resist flame, but also prevent fuming, avoid dripping and produce toxic gas, and further reduce the use amount of other auxiliary agents.

The raw materials of the indoor thick steel structure fireproof coating comprise, by mass, 5-15 parts of magnesium hydroxide, preferably 6-14 parts of magnesium hydroxide, and more preferably 9-12 parts of magnesium hydroxide. The source of the magnesium hydroxide is not particularly limited in the present invention, and commercially available products well known in the art may be used. In the invention, the magnesium hydroxide also has the functions of flame retardance and smoke suppression, so that the flame retardant of the indoor thick steel structure fireproof coating can be used in cooperation with aluminum hydroxide to further improve the flame retardance of the fireproof coating.

The raw materials of the indoor thick-type steel structure fireproof coating comprise, by mass, 1-3 parts of porous active silicon materials, preferably 1.3-2.8 parts, and more preferably 1.8-2.2 parts. The source of the magnesium hydroxide is not particularly limited in the present invention, and commercially available products well known in the art may be used. In the present invention, the particle size of the porous active silicon material is preferably 30 μm or less, more preferably 25 μm or less. The porous active silicon material can be used as a framework of a fireproof coating to adsorb other raw material components in a three-dimensional space network structure, so that a good heat preservation and insulation effect is achieved, and the steel is prevented from being heated and deformed by temperature conduction when the steel structure is fired.

The raw materials of the indoor thick-type steel structure fireproof coating comprise, by mass, 5-15 parts of titanium dioxide, preferably 6-14 parts of titanium dioxide, and more preferably 8-12 parts of titanium dioxide. The source of the titanium dioxide is not specially limited, and the titanium dioxide is prepared from commercially available products well known in the field. In the present invention, the titanium dioxide is preferably anatase type titanium dioxide. The particle size of the titanium white powder material is preferably less than or equal to 30 mu m, and more preferably less than or equal to 25 mu m. In the invention, the titanium dioxide has high chemical stability, can not be decomposed when being heated, can be used as a white auxiliary filler of a fireproof coating, and can prevent the coating from cracking when being fired.

The raw materials of the indoor thick-type steel structure fireproof coating comprise, by mass, 10-20 parts of pure acrylic emulsion, preferably 11-19 parts of pure acrylic emulsion, and more preferably 13-17 parts of pure acrylic emulsion. The source of the acrylic emulsion is not particularly limited in the present invention, and commercially available products well known in the art may be used. In the invention, the pure acrylic emulsion can be used as an auxiliary binder of a sodium silicate solution, the viscosity of the fireproof coating can be further improved, the adhesion force with a steel structure matrix is stronger after hardening, the fireproof coating is more favorable for thick coating on the surface of a steel structure, and meanwhile, the fireproof coating has good weather resistance and the effect of improving the film forming and cracking resistance.

The raw materials of the indoor thick steel structure fireproof coating comprise, by mass, 0.2-1 part of a dispersing agent, preferably 0.22-0.5 part, and more preferably 0.25-0.4 part. In the invention, the dispersant is preferably one or more of sodium polycarboxylate or sodium polyphosphate dispersants. The dispersant provided by the invention has high-temperature stability, is not easy to decompose and volatilize when being heated, can improve the surface properties of other components in the fireproof coating by adding a small amount of dispersant, and can be prepared into slurry with uniform dispersion and strong stability, so that the slurry has good slurry coating capability when being coated on the surface of a steel structure.

The raw materials of the indoor thick steel structure fireproof coating comprise, by mass, 0.2-1 part of a defoaming agent, preferably 0.22-0.5 part, and more preferably 0.25-0.4 part. In the invention, the defoaming agent is preferably one or more of a water-based paint defoaming agent, an organic siloxane or polyether defoaming agent. The defoaming agent can improve the surface tension of other components in the fireproof coating, avoids uneven coating density caused by bubbles existing in the preparation or coating process of the slurry, and is beneficial to forming a uniform and compact thick fireproof coating, so that the fireproof coating has better flame retardant and heat insulation effects.

The raw materials of the indoor thick steel structure fireproof coating comprise, by mass, 0.2-1 part of a plasticizer, preferably 0.22-0.55 part, and more preferably 0.25-0.4 part. In the invention, the plasticizer is preferably one or more of dibutyl phthalate or dioctyl phthalate. The plasticizer can increase the plasticity and the fluidity of the fireproof coating, obtain a better thick coating effect, has low volatility and cannot cause secondary pollution when being fired.

The raw material components of the indoor thick steel structure fireproof coating comprise, by mass, 0.2-1 part of a leveling agent, preferably 0.22-0.55 part, and more preferably 0.25-0.4 part. In the invention, the leveling agent is preferably one or more of organosilicon, polyurethane or polyacrylic leveling agent. The leveling agent can promote the fireproof coating to form a flat, smooth and uniform coating film in the drying film-forming process, and avoids the defects of shrinkage cavity and the like.

The raw materials of the indoor thick steel structure fireproof coating comprise, by mass, 0.2-1.5 parts of a film-forming additive, preferably 0.3-1.3 parts, and more preferably 0.5-0.9 part. In the invention, the film forming auxiliary agent is preferably one or more of alcohol ester twelve or dipropylene glycol butyl ether. The film-forming additive can improve the film-forming property of the fireproof coating, so that the coating is not easily influenced by the coating environment and obtains a good film-forming effect.

The raw material components of the indoor thick-type steel structure fireproof coating provided by the invention comprise, by mass, 20-60 parts of water, preferably 25-50 parts of water, and more preferably 35-45 parts of water. The water is used as a solvent, so that the viscosity of the coating can be adjusted, and the coating of the fireproof coating is facilitated.

The indoor thick steel structure fireproof coating provided by the invention adopts the small-particle-size fly ash hollow microspheres with the particle size of less than or equal to 180 mu m and the expanded perlite as the heat-insulating filler of the fireproof coating, and the fireproof coating has good flame retardance by utilizing the characteristics of high chemical stability and low heat conductivity coefficient of the material; the sodium silicate solution is used as a binder instead of cement, so that cracking during initial drying can be effectively avoided, the use of organic emulsion and auxiliaries is reduced, and the problem of large smoke generation when the paint is fired is avoided; aluminum hydroxide and magnesium hydroxide are used as flame retardants, and can absorb a large amount of heat when heated and decompose to form a hard enamel layer, so that a hole framework of the fireproof coating when fired is established; in addition, the porous active silicon material is added to be used as a framework of the coating; meanwhile, the aluminum silicate fiber is added, so that the coating has excellent mechanical property while the cracking of the fireproof coating is avoided. In addition, the invention fully recycles the large-particle-size hollow microspheres (larger than 180 mu m) to prepare the sodium silicate solution, thereby avoiding resource waste and saving the cost; meanwhile, the waste liquid generated by acid leaching in the process of preparing the sodium silicate solution is adopted to prepare the aluminum hydroxide, so that the pollution of waste to the environment is avoided, the resource recycling is realized, and the cost is greatly saved.

The invention mixes magnesium hydroxide, aluminum hydroxide, titanium white, porous active silicon material and aluminum silicate fiber, and then mixes with sodium silicate solution, water and dispersant to obtain slurry A.

The operation of mixing the magnesium hydroxide, the aluminum hydroxide, the titanium dioxide, the porous active silicon material and the aluminum silicate fiber is not particularly limited, and the technical scheme for preparing the mixed material, which is well known to the technical personnel in the field, is adopted.

In the present invention, the mixing with the sodium silicate solution, water and the dispersant is preferably performed under high-speed stirring conditions; the high-speed stirring speed is preferably 3000-4000 r/min, and more preferably 3500-3800 r/min; the high-speed stirring time is preferably 15-30 min, and more preferably 20-25 min.

After the slurry A is obtained, the slurry A is mixed with the pure acrylic emulsion, the defoaming agent, the plasticizer, the flatting agent and the film forming additive to obtain the slurry B.

In the invention, the mixing of the slurry A, the pure acrylic emulsion, the defoaming agent, the plasticizer, the flatting agent and the film-forming assistant is preferably carried out under the condition of medium-speed stirring; the speed of the medium-speed stirring is preferably 1500-2000 r/min, more preferably 1600-1800 r/min, and the time of the medium-speed stirring is preferably 5-20 min, more preferably 10-15 min.

After the slurry B is obtained, the slurry B is mixed with the fly ash hollow microspheres and the expanded perlite to obtain the coating.

In the invention, the mixing of the slurry B, the fly ash hollow microspheres and the expanded perlite is preferably carried out under the condition of low-speed stirring; the low-speed stirring speed is preferably 1000-1500 r/min, more preferably 1200-1300 r/min, and the low-speed stirring time is preferably 5-15 min, more preferably 8-12 min. In the present invention, when the stirring speed is within the above range, the raw material can be uniformly dispersed and the liquid can be prevented from splashing.

In the invention, after the slurry B is mixed with the fly ash cenosphere and the expanded perlite, preferably still standing is further included. In the invention, the standing time is preferably 5-15 min, and more preferably 10-15 min. The invention can make the bubbles generated in the stirring process fully escape through standing.

The preparation method provided by the invention has the advantages that the components are uniformly dispersed and have good compatibility, the slurry has good slurry hanging capability and film forming capability, the coating has no air holes, the texture is compact, the coating does not fall off, the mechanical property, the heat insulation and the flame retardant property are excellent, the preparation process is simple, and the cost is low.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The kinds and the ratios of the raw materials of examples 1 to 5 are shown in Table 1.

Example 1

The preparation steps of the indoor thick-type steel structure fireproof coating prepared in the embodiment are as follows:

sieving the hollow fly ash microbeads through a 80-mesh standard sieve, and ball-milling the unsieved microbeads (with the particle size of more than 180 mu m) at the rotating speed of 300r/min for 4 hours until the particle size is about 19 mu m.

Grinding and uniformly mixing the pulverized fuel ash hollow microspheres subjected to ball milling and compound alkali according to the mass ratio of 0.5:1, and roasting at 700 ℃ for 1h to obtain nepheline; the compound alkali is sodium carbonate and sodium hydroxide, and the mass ratio is 0.5: 1.

And (3) performing acid leaching on the nepheline obtained in the step for 10min by using hydrochloric acid with the mass concentration of 8% at the temperature of 95 ℃ to obtain acid residue and acid leaching filtrate, wherein the liquid-solid mass ratio during acid leaching is 15: 1.

And adding the acid residue obtained in the step into a sodium hydroxide solution for alkali dissolution, wherein the liquid-solid mass ratio is 25:1, and then extracting the mould to obtain a sodium silicate solution with the modulus of 1.65, wherein the mass concentration of sodium hydroxide used in the alkali dissolution is 5%, the temperature of the alkali dissolution is 60 ℃, and the time of the alkali dissolution is 6 hours.

And (3) adding a sodium hydroxide solution with the mass concentration of 20% into the acid leaching filtrate obtained in the step to adjust the pH value to 11, and filtering to obtain an alkaline solution.

And (3) introducing excessive carbon dioxide into the alkaline solution in the step to obtain a suspension, and drying the suspension in an oven at 120 ℃ for 5 hours to obtain the aluminum hydroxide.

Uniformly mixing magnesium hydroxide, aluminum hydroxide, anatase titanium dioxide with the particle size of less than or equal to 30 microns, porous active silicon material with the particle size of less than or equal to 30 microns and aluminum silicate fiber with the length of less than or equal to 2mm, and then stirring at a high speed of 3000r/min with a sodium silicate solution, water and a dispersing agent for 30min to obtain slurry A;

mixing the slurry A obtained in the step with a pure acrylic emulsion, a defoaming agent, a plasticizer, a flatting agent and a film-forming additive for 20min by stirring at a medium speed of 1500r/min to obtain slurry B;

and (3) stirring and mixing the slurry B obtained in the step with sieved fly ash hollow microspheres with small particle sizes less than or equal to 180 mu m and expanded perlite with expansion multiple of 13 times and particle size of 3mm at a low speed of 1000r/min for 15min, and standing for 15min to obtain the coating.

Example 2

The indoor thick steel structure fireproof coating prepared by the embodiment specifically comprises the following preparation steps:

sieving the hollow fly ash microbeads with a 80-mesh standard sieve, and ball-milling the unsieved microbeads (with the particle size of 180 mu m) at the rotating speed of 400r/min for 5h until the particle size is about 17 mu m.

Grinding and uniformly mixing the pulverized fuel ash hollow microspheres subjected to ball milling and compound alkali according to the mass ratio of 1:1, and roasting at 790 ℃ for 2h to obtain nepheline; the compound alkali is sodium carbonate and sodium hydroxide, and the mass ratio of the compound alkali to the sodium hydroxide is 1: 1.

And (3) performing acid leaching on the nepheline obtained in the step for 15min by using hydrochloric acid with the mass concentration of 12% at the temperature of 80 ℃ to obtain acid residue and acid leaching filtrate, wherein the liquid-solid mass ratio during acid leaching is 12: 1.

And adding the acid residue obtained in the step into a sodium hydroxide solution for alkali dissolution, wherein the liquid-solid mass ratio is 20:1 during the alkali dissolution, and then extracting the mould to obtain a sodium silicate solution with the modulus of 1.7, wherein the mass concentration of the sodium hydroxide solution used during the alkali dissolution is 10%, the temperature of the alkali dissolution is 90 ℃, and the time of the alkali dissolution is 4 hours.

And (3) adding a sodium hydroxide solution with the mass concentration of 20% into the acid leaching filtrate obtained in the step to adjust the pH value to 11.5, and filtering to obtain an alkaline solution.

And (3) introducing excessive carbon dioxide into the alkaline solution in the step to obtain a suspension, and drying the suspension in an oven at 110 ℃ for 6 hours to obtain the aluminum hydroxide.

Uniformly mixing magnesium hydroxide, aluminum hydroxide, anatase titanium dioxide with the particle size of less than or equal to 30 microns, porous active silicon material with the particle size of less than or equal to 30 microns and aluminum silicate fiber with the length of less than or equal to 2mm, and then stirring at high speed of 3250r/min with a sodium silicate solution, water and a dispersing agent for 25min to obtain slurry A;

mixing the slurry A obtained in the step with a pure acrylic emulsion, a defoaming agent, a plasticizer, a flatting agent and a film-forming assistant by stirring at a medium speed of 1600r/min for 15min to obtain slurry B;

and (3) mixing the slurry B obtained in the step with sieved fly ash hollow microspheres with the particle size of less than or equal to 180 mu m and expanded perlite with the expansion multiple of 14 times and the particle size of 4mm at a low speed of 1100r/min for 15min, and standing for 15min to obtain the coating.

Example 3

sieving the hollow fly ash microbeads with a 80-mesh standard sieve, and ball-milling the unsieved microbeads (with the particle size of 180 mu m) at the rotating speed of 400r/min for 6h until the particle size is about 16 mu m.

Grinding and uniformly mixing the pulverized fuel ash hollow microspheres subjected to ball milling and compound alkali according to the mass ratio of 1.2:1, and roasting at 880 ℃ for 3 hours to obtain nepheline; the compound alkali is sodium carbonate and sodium hydroxide, and the mass ratio of the compound alkali to the sodium hydroxide is 1.5: 1.

And (3) performing acid leaching on the nepheline obtained in the step for 20min by using hydrochloric acid with the mass concentration of 15% at the temperature of 70 ℃ to obtain acid residue and acid leaching filtrate, wherein the liquid-solid mass ratio during acid leaching is 9: 1.

And adding the acid residue obtained in the step into a sodium hydroxide solution for alkali dissolution, wherein the liquid-solid mass ratio is 15:1 during the alkali dissolution, and then extracting the mould to obtain a sodium silicate solution with the modulus of 1.8, wherein the mass concentration of the sodium hydroxide solution used during the alkali dissolution is 15%, the temperature of the alkali dissolution is 110 ℃, and the time of the alkali dissolution is 2 hours.

And (3) adding a sodium hydroxide solution with the mass concentration of 20% into the acid leaching filtrate obtained in the step to adjust the pH value to 12, and filtering to obtain an alkaline solution.

Uniformly mixing magnesium hydroxide, aluminum hydroxide, anatase titanium dioxide with the particle size of less than or equal to 30 microns, porous active silicon material with the particle size of less than or equal to 30 microns and aluminum silicate fiber with the length of less than or equal to 2mm, and then mixing with a sodium silicate solution, water and a dispersing agent by high-speed stirring at 3500r/min for 20min to obtain slurry A;

mixing the slurry A obtained in the step with a pure acrylic emulsion, a defoaming agent, a plasticizer, a flatting agent and a film-forming additive for 10min at a medium speed of 1700r/min to obtain slurry B;

and (3) stirring and mixing the slurry B obtained in the step with sieved fly ash hollow microspheres with the particle size of less than or equal to 180 mu m and expanded perlite with the expansion multiple of 13 times and the particle size of 3mm at a slow speed of 1200r/min for 10min, and standing for 15min to obtain the coating.

Example 4

sieving the hollow fly ash microbeads through a 80-mesh standard sieve, and ball-milling the unsieved microbeads (with the particle size of more than 180 mu m) at the rotating speed of 350r/min for 7 hours until the particle size is about 16 mu m.

Grinding and uniformly mixing the pulverized fuel ash hollow microspheres subjected to ball milling and compound alkali according to the mass ratio of 2:1, and roasting at 950 ℃ for 4 hours to obtain nepheline; the compound alkali is sodium carbonate and sodium hydroxide, and the mass ratio of the compound alkali to the sodium hydroxide is 2: 1.

And (3) performing acid leaching on the nepheline obtained in the step for 50min by using hydrochloric acid with the mass concentration of 17% at the temperature of 50 ℃ to obtain acid residue and acid leaching filtrate, wherein the liquid-solid mass ratio during acid leaching is 7: 1.

And adding the acid residue obtained in the step into a sodium hydroxide solution for alkali dissolution, wherein the liquid-solid mass ratio is 10:1 during the alkali dissolution, and then extracting the mould to obtain a sodium silicate solution with the modulus of 1.9, wherein the mass concentration of the sodium hydroxide solution used during the alkali dissolution is 20%, the temperature of the alkali dissolution is 130 ℃, and the time of the alkali dissolution is 1 h.

And (3) adding a sodium hydroxide solution with the mass concentration of 20% into the acid leaching filtrate obtained in the step to adjust the pH value to 12.5, so as to obtain an alkaline solution.

And (3) introducing excessive carbon dioxide into the alkaline solution in the step to obtain a suspension, and drying the suspension in an oven at 120 ℃ for 6 hours to obtain the aluminum hydroxide.

Uniformly mixing magnesium hydroxide, aluminum hydroxide, anatase titanium dioxide with the particle size of less than or equal to 30 microns, porous active silicon material with the particle size of less than or equal to 30 microns and aluminum silicate fiber with the length of less than or equal to 2mm, and then stirring at a high speed of 3750r/min with a sodium silicate solution, water and a dispersing agent for 15min to obtain slurry A;

mixing the slurry A obtained in the step with a pure acrylic emulsion, a defoaming agent, a plasticizer, a flatting agent and a film-forming additive at a medium speed of 1800r/min by stirring for 8min to obtain slurry B;

and (3) mixing the slurry B obtained in the step with sieved fly ash hollow microspheres with the particle size of less than or equal to 180 mu m and expanded perlite with the expansion multiple of 14 times and the particle size of 4mm at a low speed of 1350r/min for 7min, and standing for 15min to obtain the coating.

Example 5

sieving the hollow fly ash microbeads with a 80-mesh standard sieve, and ball-milling the unsieved microbeads (with the particle size of 180 mu m) at the rotating speed of 300r/min for 8h until the particle size is about 16 mu m.

Grinding and uniformly mixing the pulverized fuel ash hollow microspheres subjected to ball milling and compound alkali according to the mass ratio of 3:1, and roasting at 1000 ℃ for 5 hours to obtain nepheline; the compound alkali is sodium carbonate and sodium hydroxide, and the mass ratio of the compound alkali to the sodium hydroxide is 2.5: 1.

And (3) performing acid leaching on the nepheline obtained in the step for 90min by using hydrochloric acid with the mass concentration of 20% at the temperature of 40 ℃ to obtain acid residue and acid leaching filtrate, wherein the liquid-solid mass ratio during acid leaching is 5: 1.

And adding the acid residue obtained in the step into a sodium hydroxide solution for alkali dissolution, wherein the liquid-solid mass ratio is 5:1 during the alkali dissolution, and then extracting the mould to obtain a sodium silicate solution with the modulus of 1.95, wherein the mass concentration of the sodium hydroxide solution used during the alkali dissolution is 30%, the temperature of the alkali dissolution is 160 ℃, and the time of the alkali dissolution is 0.5 h.

And (3) adding a sodium hydroxide solution with the mass concentration of 20% into the acid leaching filtrate obtained in the step to adjust the pH value to 13, so as to obtain an alkaline solution.

Uniformly mixing magnesium hydroxide, aluminum hydroxide, anatase titanium dioxide powder with the particle size of less than or equal to 30 microns, porous active silicon material with the particle size of less than or equal to 30 microns and aluminum silicate fiber with the length of less than or equal to 2mm, and then stirring at a high speed of 4000r/min with a sodium silicate solution, water and a dispersing agent for 15min to obtain slurry A;

mixing the slurry A obtained in the step with a pure acrylic emulsion, a defoaming agent, a plasticizer, a flatting agent and a film-forming assistant by stirring at a medium speed of 2000r/min for 5min to obtain slurry B;

and (3) stirring and mixing the slurry B obtained in the step with sieved fly ash hollow microspheres with the particle size of less than or equal to 180 mu m and expanded perlite with the expansion multiple of 13 times and the particle size of 3mm at a slow speed of 1500r/min for 5min, and standing for 15min to obtain the coating.

TABLE 1 EXAMPLES 1 TO 5, component kinds and compounding ratio (unit: parts by mass)

Performance comparison experiment

The examples of the invention were compared with other product performance tests of the same type: as a control sample, a commercially available NH (ZHH-2) type fire retardant coating for an indoor thick steel structure was selected.

The above samples were tested under the same conditions according to GB14907-2002, and the experimental results of each sample are shown in Table 2.

The fire resistance test is carried out by adopting a small plate back surface fire burning method, and a fire resistance test device of the fire retardant coating in the embodiment of the invention is shown in figure 1, wherein 1 is a bracket used for supporting a double-needle surface thermocouple; 2 is an alcohol blast burner which is arranged below the steel plate sample and used for heating the steel plate sample; 3, a steel plate sample coated with the coating is fixed in a sample groove; 4, the heat preservation cotton is arranged on the back of the fire-receiving surface of the steel plate sample 3 and is used for preserving heat, so that the heat loss caused by prolonging the heating time of the steel plate is avoided, and the fire burning condition of the back of the steel plate sample is more accurately tested; 5 is a double-needle surface thermocouple, 6 is a K-type thermocouple, the tail end of the circuit is connected with the back of the fire-receiving surface of the steel plate sample 3, the temperature can be converted into a thermoelectromotive force signal, and the thermoelectromotive force signal is transmitted to a digital display instrument 7 for detecting the temperature rise of the steel plate in real time.

The heating temperature rise curve of the fire resistance testing device of the fireproof coating in the embodiment of the invention is shown in FIG. 2, wherein the abscissa represents the steel fire exposure time (unit: min), and the ordinate represents the temperature rise temperature (unit: DEG C) of the steel at a certain fire exposure temperature. The fire time is about 1min, the temperature of the steel can be rapidly increased, the critical temperature (540 ℃) can be reached within about 5min according to the standard fire temperature rise curve along with the extension of the fire time, and the bearing capacity is basically lost, so that accidents such as building collapse are caused. The device for testing the fire resistance performance in the experiment of the application reaches the critical temperature in about 9min, and the maximum temperature of the outer flame of the alcohol blast lamp after stable combustion reaches 820 ℃, so that the device can meet the requirement of the fire resistance test of the fireproof coating.

The fire resistance evaluation index is 3h of back temperature of a burning sample.

TABLE 2 indoor thick steel structure fireproof paint performance contrast experiment result table

The test results shown in table 2 show that: the sample can be dried in a short time of not more than 2.5h, the improvement of the construction efficiency is facilitated, the crack resistance requirement specified in GB14907-2002 is met in the early drying stage, the bonding strength can reach 0.15-0.26 MPa, the compressive strength can reach 0.8-1.1 MPa, and the dry density is 687-801 kg/m³When the thickness of the coating is 25-28.4 mm, the back temperature end point temperature of the sample after 3h burning is 166.5-175.1 ℃, the water resistance and the cold and heat cycle resistance meet the requirements of GB14907-2002, and the coating does not have the conditions of layer forming, foaming, cracking and falling off. Moreover, part of the technical performance of the product is superior to the performance indexes of national standard and comparison samples, and the main outstanding performance is embodied in drying time, bonding strength and fire resistance.

In conclusion, according to the indoor thick steel structure fireproof coating provided by the invention, the hollow microspheres with small particle sizes are used as the heat-insulating functional filler of the fireproof coating, and the residual waste microspheres (with large particle sizes) after screening are utilized to prepare the sodium silicate solution binder and the aluminum hydroxide fire retardant required in the coating, so that the resource utilization of the fly ash hollow microspheres is realized. The physical and chemical properties and the fire-proof performance of the thick steel structure fire-proof coating are enhanced by the large amount of the small-particle-size hollow microspheres, and the obtained product has the characteristics of high bonding strength, high temperature resistance, good weather resistance, strong fire resistance and the like.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. An indoor thick steel structure fireproof coating comprises the following components in parts by mass:

5-20 parts of fly ash hollow microspheres, 20-60 parts of sodium silicate solution, 5-10 parts of expanded perlite, 1-3 parts of aluminum silicate fibers, 5-15 parts of aluminum hydroxide, 5-15 parts of magnesium hydroxide, 1-3 parts of porous active silicon materials, 5-15 parts of titanium dioxide, 10-20 parts of pure acrylic emulsion, 0.2-1 part of dispersing agent, 0.2-1 part of defoaming agent, 0.2-1 part of plasticizer, 0.2-1 part of flatting agent, 0.2-1.5 parts of film forming assistant and 20-60 parts of water; the particle size of the fly ash hollow microsphere is less than or equal to 180 mu m;

the modulus of the sodium silicate solution is 1.6-2.2;

the preparation of the sodium silicate solution comprises the following steps:

(1) mixing the compound alkali and the fly ash hollow micro-beads, and roasting to obtain nepheline; the compound alkali comprises sodium carbonate and sodium hydroxide; the particle size of the fly ash cenosphere in the step (1) is more than 180 mu m;

(3) carrying out alkali dissolution on the acid sludge obtained in the step (2), and then extracting a mold to obtain a sodium silicate solution;

the mass ratio of sodium carbonate to sodium hydroxide in the compound alkali in the step (1) is (0.5-2.5): 1; the mass ratio of the fly ash hollow microspheres to the complex alkali is (0.5-3): 1; the roasting temperature is 700-1000 ℃, and the roasting time is 1-5 h.

2. The fire retardant coating for the indoor thick-gauge steel structure as claimed in claim 1, wherein the preparation of the aluminum hydroxide comprises the steps of:

(a) taking the acid leaching filtrate obtained in the step (2) in the claim 1, adjusting the pH value to 11-13, and filtering to obtain an alkaline solution;

3. The fire retardant coating for the indoor thick steel structure as claimed in claim 1, wherein the titanium dioxide is anatase titanium dioxide.

4. The preparation method of the indoor thick-type steel structure fireproof coating as claimed in any one of claims 1 to 3, comprising the following steps: