阅读说明：本技术 一种钢渣基保温填料极其制备方法和应用 (Steel slag-based heat-insulating filler and preparation method and application thereof ) 是由 陈尚鸿 胡宗辉 谢禄丁 郭汉彬 张德长 罗永斌 于 2021-08-12 设计创作，主要内容包括：本发明涉及建筑材料领域,尤其涉及一种钢渣基保温填料极其制备方法和应用,所述制备方法,包括以下步骤：(S.1)将钢渣粉碎成粉料后进行磁筛,除去其中的铁屑,然后向粉料均匀喷洒硅烷偶联剂溶液,干燥待用；(S.2)按照配方称取原料备用,所述配方按照重量份数计包括：钢渣100份、粘结剂40～60份、渗透剂5～10份、造孔剂30～50份以及助熔剂1～5份；(S.3)将各原料混合均匀后,模压形成球形颗粒；(S.4)将球形颗粒进行烧结,得到保温填料前驱体；(S.5)将保温填料前驱体用超临界二氧化碳处理,得到钢渣基保温填料成品。本发明克服了现有技术中的钢渣的回收利用率较低的缺陷,能够将钢渣进行回收再利用,且有良好的隔热效果,能够在保温混凝土中有效应用。(The invention relates to the field of building materials, in particular to a steel slag-based heat-insulating filler, a preparation method and application thereof, wherein the preparation method comprises the following steps: (S.1) crushing the steel slag into powder, then carrying out magnetic screening to remove scrap iron, then uniformly spraying a silane coupling agent solution on the powder, and drying for later use; (S.2) weighing the raw materials according to a formula for later use, wherein the formula comprises the following components in parts by weight: 100 parts of steel slag, 40-60 parts of a binder, 5-10 parts of a penetrating agent, 30-50 parts of a pore-forming agent and 1-5 parts of a fluxing agent; (S.3) uniformly mixing the raw materials, and carrying out die pressing to form spherical particles; (S.4) sintering the spherical particles to obtain a heat-preservation filler precursor; and (S.5) treating the heat-preservation filler precursor with supercritical carbon dioxide to obtain a steel slag-based heat-preservation filler finished product. The invention overcomes the defect of low recycling rate of the steel slag in the prior art, can recycle the steel slag, has good heat insulation effect, and can be effectively applied to heat insulation concrete.)

1. The preparation method of the steel slag-based heat-insulating filler is characterized by comprising the following steps of:

(S.1) crushing the steel slag into powder, then carrying out magnetic screening to remove scrap iron, then uniformly spraying a silane coupling agent solution on the powder, and drying for later use;

(S.2) weighing the raw materials according to a formula for later use, wherein the formula comprises the following components in parts by weight: 100 parts of steel slag, 40-60 parts of a binder, 5-10 parts of a penetrating agent, 30-50 parts of a pore-forming agent and 1-5 parts of a fluxing agent;

wherein the binder is hyperbranched polysiloxane with an end group of a boron-containing compound structural unit with reactivity;

(S.3) uniformly mixing the raw materials, and carrying out die pressing to form spherical particles;

(S.4) sintering the spherical particles to obtain a heat-preservation filler precursor;

and (S.5) treating the heat-preservation filler precursor with supercritical carbon dioxide to obtain a steel slag-based heat-preservation filler finished product.

2. The method for preparing the steel slag-based heat preservation filler according to claim 1, wherein the powder in the step (S.1) has a particle size of 1-50 μm, and the silane coupling agent solution is added in an amount of 1-5 wt% based on the mass of the powder.

3. The method for preparing the steel slag-based heat preservation filler according to claim 1 or 2, wherein the silane coupling agent solution comprises 15-25% by mass of silane coupling agent with amino and alkoxy groups, 40-60% by mass of ethanol and the balance of water.

4. The method of claim 1, wherein the binder of step (S.2) has a structure represented by formula (I):

formula (I).

5. The method for preparing the steel slag-based heat preservation filler as claimed in claim 1 or 4, wherein the binder is prepared by the following steps:

(a) and (3) synthesis of hyperbranched monomer: under the condition of nitrogen, sequentially weighing vinyltrimethoxysilane and dimethylchlorosilane according to the molar weight of 1:3, dissolving the vinyltrimethoxysilane and the dimethylchlorosilane in an organic solvent, adding the organic solvent into a reactor, adding a catalyst ferric chloride into the reactor, reacting for 2-5 hours at 45-60 ℃, and removing the catalyst and the organic solvent to obtain a hyperbranched monomer;

(b) and (3) synthesis of hyperbranched resin: under the condition of nitrogen, dissolving a hyperbranched monomer in an organic solvent, adding the organic solvent into a reactor, then adding a platinum catalyst, stirring and reacting for 3-5 h at 85-95 ℃, and removing the catalyst and the organic solvent to obtain a hyperbranched resin with silicon and hydrogen as end groups;

(c) end group modification: dissolving hyperbranched resin in an organic solvent under the condition of nitrogen, adding a catalyst of tripentafluorophenylboronane, dropwise adding trimethyl borate after uniformly stirring, reacting for 1-3 h at 20-40 ℃, and evaporating to remove the solvent to obtain the binder.

6. The method for preparing steel slag-based heat preservation filler according to claim 1, wherein the sintering procedure in the step (S.4) is as follows:

and (3) curing: preserving the heat for 10-45 min at 110-150 ℃;

pre-burning: preserving the heat for 1-3 h at 250-300 ℃;

post-firing: and preserving heat for 3-5 hours at the temperature of 600-800 ℃.

7. The method for preparing the steel slag-based heat preservation filler according to claim 1, wherein the supercritical carbon dioxide treatment in the step (S.5) is performed at a pressure of 10-25 MPa, a temperature of 35-45 ℃ and a supercritical treatment time of 0.5-3 h.

8. The steel slag-based heat-insulating filler obtained by the preparation method of any one of claims 1 to 7 is characterized in that the diameter of the heat-insulating filler is 0.5-3 cm, the diameter of the holes is 50-200 μm, and the length of the holes is 50-50000 μm.

9. The application of the steel slag-based heat-insulating filler obtained by the preparation method of any one of claims 1-7 in heat-insulating concrete.

Technical Field

The invention relates to the field of building materials, in particular to a steel slag-based heat-insulating filler, a preparation method and application thereof.

Background

The steel slag is waste slag generated in the metallurgical industry, the generation rate of the steel slag is 8% -15% of the yield of crude steel, and the worldwide discharge amount of the steel slag in 2012 is about 1.8 hundred million t. The amount of steel slag produced in China is rapidly increased along with the rapid development of the steel industry, so the problems of waste slag treatment and resource utilization of steel enterprises are more and more emphasized.

At present, the recycling rate of the steel slag is low, and particularly the utilization rate of the converter steel slag which is called poor cement clinker is only 10-20%. Because steel slag produced by domestic iron and steel enterprises cannot be treated in time, a large amount of steel slag occupies land and pollutes the environment. However, steel slag is not an unusable solid waste, which contains a large amount of available components such as calcium oxide, iron and magnesium oxide. Therefore, as a 'resource misplaced', the comprehensive utilization of the steel slag can create economic and environmental benefits for steel enterprises, and it is necessary and urgent to select a proper treatment process and utilization approach to develop the recycling value of the steel slag.

For example, the application number is CN202010246204.9 steel slag concrete replacing broken stone and the preparation method. The steel slag concrete preparation raw materials for replacing broken stones by steel slag provided by the invention comprise: steel slag, cement, fly ash, mineral powder, sand and a polycarboxylic acid water reducing agent. The waste steel slag is used as aggregate, and is thermally braised to ensure that free calcium oxide and free magnesium oxide in the steel slag are subjected to hydration reaction, so that the self expansion and contraction are reduced; and the water content of the steel slag is saturated, so that the problem of quick slump loss of the steel slag concrete with the steel slag replacing broken stones in the production process is solved. Although the waste steel slag can be recycled as the crushed stone, the prepared concrete does not have other unique effects, so that the advantages of the concrete are not obvious compared with the traditional concrete.

Disclosure of Invention

The invention provides a steel slag-based heat-insulating filler, a preparation method and application thereof, aiming at overcoming the defects that the recycling rate of steel slag in the prior art is low and no special function exists in the recycling process, so as to overcome the technical problems.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a preparation method of a steel slag-based heat-insulating filler comprises the following steps:

(S.1) crushing the steel slag into powder, then carrying out magnetic screening to remove scrap iron, then uniformly spraying a silane coupling agent solution on the powder, and drying for later use;

(S.2) weighing the raw materials according to a formula for later use, wherein the formula comprises the following components in parts by weight: 100 parts of steel slag, 40-60 parts of a binder, 5-10 parts of a penetrating agent, 30-50 parts of a pore-forming agent and 1-5 parts of a fluxing agent;

wherein the binder is hyperbranched polysiloxane with an end group of a boron-containing compound structural unit with reactivity

(S.3) uniformly mixing the raw materials, and carrying out die pressing to form spherical particles;

(S.4) sintering the spherical particles to obtain a heat-preservation filler precursor;

and (S.5) treating the heat-preservation filler precursor with supercritical carbon dioxide to obtain a steel slag-based heat-preservation filler finished product.

The steel slag-based heat-insulating filler adopts steel slag as a raw material, the steel slag is crushed into powder and then mixed with additives such as a binder, a pore-forming agent and the like to prepare spherical particles, and the binder and the pore-forming agent in the spherical particles are removed after sintering, so that a porous structure is obtained. Due to the existence of the porous structure, the heat insulation material has good heat insulation effect, so that the heat insulation material can be applied to the field needing heat preservation and heat insulation. Meanwhile, the porous structure also endows the filler with a good sound insulation effect, and the application range of the filler is extended.

The steel slag is crushed and then passes through the magnetic sieve, so that the iron powder in the steel slag can be sieved, and the steel slag can be recycled as a steel-making raw material. After the iron powder is removed, the addition of the silane coupling agent can modify the surface of the steel slag, so that the connection strength between the steel slag and the binder is improved, and the stability of the obtained spherical particles can be greatly improved after compression molding.

The binder adopts hyperbranched polysiloxane with the end group of a boron-containing compound structural unit with reactivity, and aims to decompose an organic chain segment in an organic silicon structure in the sintering process so as to obtain a silicon dioxide skeleton, wherein the silicon content in steel slag can be increased. Meanwhile, the boron-containing compound structural unit can perform coupling reaction with a silane coupling agent, so that spherical particles formed by die pressing are more stable. Meanwhile, the boron-containing compound structural unit can be gradually decomposed into compounds (such as boric acid, borax and boron oxide) with boron-oxygen structural units in the sintering process, and the melting points of peripheral substances such as calcium oxide, silicon dioxide and magnesium oxide can be reduced, so that the substances are fused and bonded to form a silicate borate structure with uniform texture and good mechanical property, and the stability of the steel slag is improved.

Meanwhile, because the steel slag is an inorganic substance and the binder is an organic compound, the compatibility of the steel slag and the binder needs to be further improved, and a certain amount of penetrant is added in the formula, so that the binder is helped to permeate into the steel slag powder, and the compatibility of the steel slag and the binder is improved. Meanwhile, the addition of the fluxing agent can also enable a part of the steel slag to form a molten state in the sintering process, and glass crystals with uniform and stable properties can be formed after cooling, so that the mechanical property and stability of the whole heat-insulating filler can be obviously improved.

After sintering, the thermal insulation filler is subjected to supercritical carbon dioxide treatment, and the first purpose of the method is to dissolve and remove the pore-forming agent which is not completely removed by carbon dioxide, and remove impurities in the porous structure of the thermal insulation filler, so that the porosity of the porous structure is improved, and the thermal insulation effect is further improved. Meanwhile, the steel slag contains a large amount of calcium oxide and magnesium oxide which have extremely high reactivity and can react and expand after meeting water, so that the problems of low stability and structural strength exist. Meanwhile, the reactivity of the heat-insulating filler is reduced, the chemical stability of the heat-insulating filler is improved, and the chemical inertia of the heat-insulating filler is improved, so that the heat-insulating filler cannot expand and deform after meeting water.

Although the scheme of carbonizing the steel slag by using carbon dioxide also exists in the prior art, gaseous carbon dioxide is usually adopted, so that the speed is low, and the supercritical carbon dioxide treatment is adopted in the invention, so that the carbonization speed can be effectively improved, and the production efficiency of the heat-insulating filler is improved. Meanwhile, the supercritical carbon dioxide has good permeability, so that the carbonization rate of the steel slag can be improved, and the steel slag positioned in the heat-insulating filler can be effectively carbonized after being matched with the porous structure.

Preferably, the particle size of the powder in the step (S.1) is 1-50 μm, and the addition amount of the silane coupling agent solution is 1-5 wt% of the mass of the powder.

Preferably, the silane coupling agent solution comprises, by mass, 15-25% of a silane coupling agent having an amino group and an alkoxy group, 40-60% of ethanol, and the balance of water.

The reason why the silane coupling agent having an amino group and an alkoxy group is used as a desired coupling agent in the present invention is that it has a fast hydrolysis rate and thus can rapidly obtain a prehydrolysis solution after mixing with water. Meanwhile, the steel slag is alkaline, so that the compatibility between the steel slag and the silane coupling agent can be improved, and the steel slag and the silane coupling agent are prevented from generating meaningless neutralization reaction.

Preferably, the silane coupling agent is one of aminopropyltriethoxysilane, aminopropyltrimethoxysilane, bis [ (3-triethoxysilyl) propyl ] amine, and aminoethylaminopropyltriethoxysilane.

Preferably, the binder of step (s.2) has the formula (i):

formula (I).

Preferably, the preparation method of the adhesive is as follows:

(a) and (3) synthesis of hyperbranched monomer: under the condition of nitrogen, sequentially weighing vinyltrimethoxysilane and dimethylchlorosilane according to the molar weight of 1:3, dissolving the vinyltrimethoxysilane and the dimethylchlorosilane in an organic solvent, adding the organic solvent into a reactor, adding a catalyst ferric chloride into the reactor, reacting for 2-5 hours at 45-60 ℃, and removing the catalyst and the organic solvent to obtain a hyperbranched monomer;

(b) and (3) synthesis of hyperbranched resin: under the condition of nitrogen, dissolving a hyperbranched monomer in an organic solvent, adding the organic solvent into a reactor, then adding a platinum catalyst, stirring and reacting for 3-5 h at 85-95 ℃, and removing the catalyst and the organic solvent to obtain a hyperbranched resin with silicon and hydrogen as end groups;

(c) end group modification: dissolving hyperbranched resin in an organic solvent under the condition of nitrogen, adding a catalyst of tripentafluorophenylboronane, dropwise adding trimethyl borate after uniformly stirring, reacting for 1-3 h at 20-40 ℃, and evaporating to remove the solvent to obtain the binder.

The synthetic route of the binder is shown as the following formula (II):

the formula (II).

Preferably, the penetrant can be selected from one or more of hydroxy silicone oil, polyethylene glycol, sodium alkyl benzene sulfonate, sodium alkyl sulfate and alkylphenol polyoxyethylene ether.

Preferably, the pore-forming agent can be selected from one or more of plant fiber, polymer fiber, starch, ammonium carbonate, ammonium bicarbonate, chitin and sucrose.

The pore-forming agent can be decomposed at high temperature, so that holes with the same size as the original size are left, the holes can effectively obstruct heat, and the heat insulation effect of the heat insulation filler is improved.

Preferably, the fluxing agent is fluorite powder, alumina, borax or cryolite.

The addition of the fluxing agent can reduce the sintering temperature of the powder during sintering, so that the components can be sintered into a main body at a lower temperature.

Preferably, the sintering procedure in step (s.4) is as follows:

and (3) curing: preserving the heat for 10-45 min at 110-150 ℃;

pre-burning: preserving the heat for 1-3 h at 250-300 ℃;

post-firing: and preserving heat for 3-5 hours at the temperature of 600-800 ℃.

The sintering procedure of the invention adopts a sectional type temperature rise procedure, wherein the binder in the steel slag can be solidified at 110-150 ℃, so that the shape of the steel slag is fixed, and the steel slag is prevented from deforming in the sintering process. After curing, heating to 250-300 ℃ for pre-burning, so that a part of organic matters in the steel slag can be decomposed to form holes, the surface of the steel slag and a part of steel slag in the steel slag can be melted under the action of a fluxing agent and a decomposed binder to form a glassy state with stable properties, internal stress in spherical particles can be distributed and released, and the phenomenon of cracking caused by direct sintering at high temperature is prevented. And finally, after-burning is carried out at 600-800 hours, the pore-forming agent can be completely removed, so that holes are left, the original loose steel slag structure can be sintered into an integrated structure, the internal stress in the steel slag structure is eliminated, and the stability of the finishing heat-preservation filler is improved. In addition, in order to improve the sintering and pore-forming efficiency, the invention preferably adopts an air atmosphere in the sintering process, so that the pore-forming agent in the sintering process can be decomposed more uniformly.

Preferably, the pressure in the supercritical carbon dioxide treatment in the step (S.5) is 10-25 MPa, the temperature is 35-45 ℃, and the supercritical treatment time is 0.5-3 h.

The steel slag-based heat-insulating filler prepared by the preparation method has the diameter of 0.5-3 cm, the diameter of the holes is 50-2000 mu m, and the length of the holes is 50-50000 mu m.

The application of the steel slag-based heat-insulating filler obtained by the preparation method in heat-insulating concrete.

Therefore, the invention has the following beneficial effects:

(1) the steel slag can be recycled, so that the environment-friendly effect is good, and the income of enterprises can be effectively improved;

(2) the heat insulation material has a porous structure with a stable structure, and can play a good heat insulation effect, so that the heat insulation material can be applied to the field needing heat insulation;

(3) the concrete has good chemical inertia and mechanical strength, and does not expand and crack under the condition of meeting water, so the concrete can be effectively applied to concrete;

(4) after being applied to concrete, the concrete can bring unique effect to the traditional concrete, and the application range of the concrete is extended.

Detailed Description

The invention is further described with reference to specific examples. Those skilled in the art will be able to implement the invention based on these teachings. Moreover, the embodiments of the present invention described in the following description are generally only some embodiments of the present invention, and not all embodiments. Therefore, all other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative effort shall fall within the protection scope of the present invention.

Example 1

A preparation method of a steel slag-based heat-insulating filler comprises the following steps:

(S.1) crushing the steel slag into powder with the particle size of 1-50 mu m, then carrying out magnetic screening to remove scrap iron, then uniformly spraying silane coupling agent solution with the mass of 1wt% of the powder mass to the powder, wherein the silane coupling agent solution comprises 15% of aminopropyltriethoxysilane, 40% of ethanol and the balance of water in percentage by mass, and drying for later use.

(S.2) weighing the raw materials according to a formula for later use, wherein the formula comprises the following components in parts by weight: 100 parts of steel slag, 40 parts of binder, 5 parts of hydroxyl silicone oil, 30 parts of cellulose and 1 part of fluorite powder.

The binder is hyperbranched polysiloxane with an end group of a boron-containing compound structural unit with reactivity, and the preparation method comprises the following steps:

(a) and (3) synthesis of hyperbranched monomer: under the condition of nitrogen, sequentially weighing vinyltrimethoxysilane and dimethylchlorosilane according to the molar weight of 1:3, dissolving the vinyltrimethoxysilane and the dimethylchlorosilane in toluene, adding the vinyltrimethoxysilane and the dimethylchlorosilane into a reactor, adding a catalyst of ferric chloride into the reactor, reacting at 45 ℃ for 2 hours, adding activated carbon to adsorb the ferric chloride after the reaction is finished, filtering to obtain filtrate, and removing the toluene in the filtrate to obtain a hyperbranched monomer;

(b) and (3) synthesis of hyperbranched resin: dissolving a hyperbranched monomer in toluene under the condition of nitrogen, adding the dissolved hyperbranched monomer into a reactor, then adding a platinum catalyst, stirring and reacting for 5 hours at 85 ℃, adding activated carbon to adsorb the platinum catalyst after the reaction is finished, filtering to obtain filtrate, and removing the toluene in the filtrate to obtain hyperbranched resin with the end group of silicon hydrogen;

(c) end group modification: dissolving hyperbranched resin in toluene under the condition of nitrogen, adding a catalyst of tripentafluorophenylboronane, uniformly stirring, dropwise adding trimethyl borate with the molar weight being 2 times that of the hyperbranched monomer, reacting for 1h at 20 ℃, and evaporating to remove the solvent to obtain the binder.

(S.3) uniformly mixing the raw materials, and carrying out die pressing to form spherical particles of 0.5 cm;

(S.4) sintering the spherical particles according to a sintering procedure, wherein the sintering procedure is as follows:

and (3) curing: keeping the temperature at 110 ℃ for 45 min;

pre-burning: keeping the temperature for 3 hours at 250 ℃;

post-firing: and (3) preserving the heat for 5 hours at 800 ℃ to obtain a heat-preservation filler precursor, wherein holes with the diameter of 50-200 mu m and the length of 500-50000 mu m are uniformly distributed in the heat-preservation filler precursor.

(S.5) treating the heat-preservation filler precursor with supercritical carbon dioxide to obtain a finished product of the steel slag-based heat-preservation filler, wherein the pressure of the supercritical carbon dioxide treatment is 10MPa, the temperature is 35 ℃, and the supercritical treatment time is 3 hours.

Example 2

A preparation method of a steel slag-based heat-insulating filler comprises the following steps:

(S.1) crushing the steel slag into powder with the particle size of 1-50 mu m, performing magnetic screening to remove scrap iron, uniformly spraying a silane coupling agent solution with the mass of 5wt% of that of the powder to the powder, wherein the silane coupling agent solution comprises 25% of aminopropyltrimethoxysilane, 60% of ethanol and the balance of water in percentage by mass, and drying for later use.

(S.2) weighing the raw materials according to a formula for later use, wherein the formula comprises the following components in parts by weight: 100 parts of steel slag, 60 parts of binder, 10 parts of polyethylene glycol, 50 parts of polyester fiber and 5 parts of alumina.

The binder is hyperbranched polysiloxane with an end group of a boron-containing compound structural unit with reactivity, and the preparation method comprises the following steps:

(a) and (3) synthesis of hyperbranched monomer: under the condition of nitrogen, sequentially weighing vinyltrimethoxysilane and dimethylchlorosilane according to the molar weight of 1:3, dissolving the vinyltrimethoxysilane and the dimethylchlorosilane in toluene, adding the vinyltrimethoxysilane and the dimethylchlorosilane into a reactor, adding a catalyst of ferric chloride into the reactor, reacting at 60 ℃ for 2 hours, adding activated carbon to adsorb the ferric chloride after the reaction is finished, filtering to obtain filtrate, and removing the toluene in the filtrate to obtain a hyperbranched monomer;

(b) and (3) synthesis of hyperbranched resin: dissolving a hyperbranched monomer in toluene under the condition of nitrogen, adding the dissolved hyperbranched monomer into a reactor, then adding a platinum catalyst, stirring and reacting for 3 hours at 95 ℃, adding activated carbon to adsorb the platinum catalyst after the reaction is finished, filtering to obtain filtrate, and removing the toluene in the filtrate to obtain hyperbranched resin with the end group of silicon and hydrogen;

(c) end group modification: dissolving hyperbranched resin in toluene under the condition of nitrogen, adding a catalyst of tripentafluorophenylboronane, uniformly stirring, dropwise adding trimethyl borate with the molar weight being 1.5 times that of the hyperbranched monomer, reacting for 1h at 40 ℃, and evaporating to remove the solvent to obtain the binder.

(S.3) uniformly mixing the raw materials, and carrying out die pressing to form spherical particles of 3 cm;

(S.4) sintering the spherical particles according to a sintering procedure, wherein the sintering procedure is as follows:

and (3) curing: keeping the temperature at 150 ℃ for 10 min;

pre-burning: keeping the temperature for 1h at 300 ℃;

post-firing: and (3) preserving the heat for 3 hours at 800 ℃ to obtain a heat-preservation filler precursor, wherein holes with the diameter of 50-200 mu m and the length of 500-50000 mu m are uniformly distributed in the heat-preservation filler precursor.

(S.5) treating the heat-preservation filler precursor with supercritical carbon dioxide to obtain a finished product of the steel slag-based heat-preservation filler, wherein the pressure of the supercritical carbon dioxide treatment is 25MPa, the temperature is 45 ℃, and the supercritical treatment time is 3 hours.

Example 3

A preparation method of a steel slag-based heat-insulating filler comprises the following steps:

(S.1) crushing the steel slag into powder with the particle size of 1-50 mu m, then carrying out magnetic screening to remove scrap iron, then uniformly spraying a silane coupling agent solution with the mass of 3wt% of the powder mass onto the powder, wherein the silane coupling agent solution comprises 20% of bis [ (3-triethoxysilyl) propyl ] amine, 50% of ethanol and the balance of water in percentage by mass, and drying for later use.

(S.2) weighing the raw materials according to a formula for later use, wherein the formula comprises the following components in parts by weight: 100 parts of steel slag, 50 parts of binder, 8 parts of sodium alkyl benzene sulfonate, 40 parts of starch and 3 parts of borax.

The binder is hyperbranched polysiloxane with an end group of a boron-containing compound structural unit with reactivity, and the preparation method comprises the following steps:

(a) and (3) synthesis of hyperbranched monomer: under the condition of nitrogen, sequentially weighing vinyltrimethoxysilane and dimethylchlorosilane according to the molar weight of 1:3, dissolving the vinyltrimethoxysilane and the dimethylchlorosilane in toluene, adding the vinyltrimethoxysilane and the dimethylchlorosilane into a reactor, adding a catalyst of ferric chloride into the reactor, reacting at 50 ℃ for 3 hours, adding activated carbon to adsorb the ferric chloride after the reaction is finished, filtering to obtain filtrate, and removing the toluene in the filtrate to obtain a hyperbranched monomer;

(b) and (3) synthesis of hyperbranched resin: dissolving a hyperbranched monomer in toluene under the condition of nitrogen, adding the dissolved hyperbranched monomer into a reactor, then adding a platinum catalyst, stirring and reacting for 4 hours at 90 ℃, adding activated carbon to adsorb the platinum catalyst after the reaction is finished, filtering to obtain filtrate, and removing the toluene in the filtrate to obtain hyperbranched resin with the end group of silicon hydrogen;

(c) end group modification: dissolving hyperbranched resin in toluene under the condition of nitrogen, adding a catalyst of tripentafluorophenylboronane, uniformly stirring, dropwise adding trimethyl borate with the molar weight being 2.5 times that of the hyperbranched monomer, reacting for 2 hours at 35 ℃, and evaporating to remove the solvent to obtain the binder.

(S.3) uniformly mixing the raw materials, and carrying out die pressing to form spherical particles of 2 cm;

(S.4) sintering the spherical particles according to a sintering procedure, wherein the sintering procedure is as follows:

and (3) curing: keeping the temperature at 130 ℃ for 30 min;

pre-burning: keeping the temperature for 2 hours at 280 ℃;

post-firing: and (3) preserving the heat for 4 hours at the temperature of 700 ℃ to obtain a heat-preservation filler precursor, wherein holes with the diameter of 50-100 micrometers and the length of 50-100 micrometers are uniformly distributed in the heat-preservation filler precursor.

And (S.5) treating the heat-preservation filler precursor with supercritical carbon dioxide to obtain a finished product of the steel slag-based heat-preservation filler, wherein the pressure of the supercritical carbon dioxide treatment is 15MPa, the temperature is 40 ℃, and the supercritical treatment time is 2 hours.

Example 4

A preparation method of a steel slag-based heat-insulating filler comprises the following steps:

(S.1) crushing the steel slag into powder with the particle size of 1-50 mu m, performing magnetic screening to remove scrap iron, uniformly spraying a silane coupling agent solution with the mass of 4.5wt% of that of the powder to the powder, wherein the silane coupling agent solution comprises, by mass, 20% of aminoethyl aminopropyl triethoxysilane, 55% of ethanol and the balance of water, and drying for later use.

(S.2) weighing the raw materials according to a formula for later use, wherein the formula comprises the following components in parts by weight: 100 parts of steel slag, 55 parts of binder, 9 parts of alkylphenol ethoxylates, 35 parts of chitin and 2.5 parts of cryolite.

The binder is hyperbranched polysiloxane with an end group of a boron-containing compound structural unit with reactivity, and the preparation method comprises the following steps:

(a) and (3) synthesis of hyperbranched monomer: under the condition of nitrogen, sequentially weighing vinyltrimethoxysilane and dimethylchlorosilane according to the molar weight of 1:3, dissolving the vinyltrimethoxysilane and the dimethylchlorosilane in toluene, adding the vinyltrimethoxysilane and the dimethylchlorosilane into a reactor, adding a catalyst of ferric chloride into the reactor, reacting at 50 ℃ for 4 hours, adding activated carbon to adsorb the ferric chloride after the reaction is finished, filtering to obtain filtrate, and removing the toluene in the filtrate to obtain a hyperbranched monomer;

(b) and (3) synthesis of hyperbranched resin: dissolving a hyperbranched monomer in toluene under the condition of nitrogen, adding the dissolved hyperbranched monomer into a reactor, then adding a platinum catalyst, stirring and reacting for 3.5 hours at 90 ℃, adding activated carbon to adsorb the platinum catalyst after the reaction is finished, filtering to obtain filtrate, and removing the toluene in the filtrate to obtain hyperbranched resin with the end group of silicon and hydrogen;

(c) end group modification: dissolving hyperbranched resin in toluene under the condition of nitrogen, adding a catalyst of tripentafluorophenylboronane, uniformly stirring, dropwise adding trimethyl borate with the molar weight being 1.5 times that of the hyperbranched monomer, reacting for 2.5h at 35 ℃, and evaporating to remove the solvent to obtain the binder.

(S.3) uniformly mixing the raw materials, and carrying out die pressing to form 1cm spherical particles;

(S.4) sintering the spherical particles according to a sintering procedure, wherein the sintering procedure is as follows:

and (3) curing: keeping the temperature at 135 ℃ for 30 min;

pre-burning: keeping the temperature for 2 hours at 260 ℃;

post-firing: and (3) preserving the heat for 3.5 hours at the temperature of 750 ℃ to obtain a heat-preservation filler precursor, wherein holes with the diameter of 50-200 mu m and the length of 50-500 mu m are uniformly distributed in the heat-preservation filler precursor.

And (S.5) treating the heat-preservation filler precursor with supercritical carbon dioxide to obtain a finished product of the steel slag-based heat-preservation filler, wherein the pressure of the supercritical carbon dioxide treatment is 12MPa, the temperature is 40 ℃, and the supercritical treatment time is 1 h.

Example 5

A preparation method of a steel slag-based heat-insulating filler comprises the following steps:

(S.1) crushing the steel slag into powder with the particle size of 1-50 mu m, then carrying out magnetic screening to remove scrap iron, then uniformly spraying silane coupling agent solution with the mass of 2.5wt% of the powder mass onto the powder, wherein the silane coupling agent solution comprises, by mass percent, 22% of aminoethyl aminopropyl triethoxysilane, 45% of ethanol and the balance of water, and drying for later use.

(S.2) weighing the raw materials according to a formula for later use, wherein the formula comprises the following components in parts by weight: 100 parts of steel slag, 55 parts of binder, 6 parts of sodium alkyl benzene sulfonate, 35 parts of cane sugar and 1.5 parts of fluorite powder.

The binder is hyperbranched polysiloxane with an end group of a boron-containing compound structural unit with reactivity, and the preparation method comprises the following steps:

(a) and (3) synthesis of hyperbranched monomer: under the condition of nitrogen, sequentially weighing vinyltrimethoxysilane and dimethylchlorosilane according to the molar weight of 1:3, dissolving the vinyltrimethoxysilane and the dimethylchlorosilane in toluene, adding the vinyltrimethoxysilane and the dimethylchlorosilane into a reactor, adding a catalyst of ferric chloride into the reactor, reacting at 60 ℃ for 2 hours, adding activated carbon to adsorb the ferric chloride after the reaction is finished, filtering to obtain filtrate, and removing the toluene in the filtrate to obtain a hyperbranched monomer;

(b) and (3) synthesis of hyperbranched resin: dissolving a hyperbranched monomer in toluene under the condition of nitrogen, adding the dissolved hyperbranched monomer into a reactor, then adding a platinum catalyst, stirring and reacting for 5 hours at the temperature of 95 ℃, adding activated carbon to adsorb the platinum catalyst after the reaction is finished, filtering to obtain filtrate, and removing the toluene in the filtrate to obtain hyperbranched resin with the end group of silicon and hydrogen;

(c) end group modification: dissolving hyperbranched resin in toluene under the condition of nitrogen, adding a catalyst of tripentafluorophenylboronane, uniformly stirring, dropwise adding trimethyl borate with the molar weight of 2.5 times of that of the hyperbranched monomer, reacting for 3 hours at 40 ℃, and evaporating to remove the solvent to obtain the binder.

(S.3) uniformly mixing the raw materials, and carrying out die pressing to form spherical particles of 3 cm;

(S.4) sintering the spherical particles according to a sintering procedure, wherein the sintering procedure is as follows:

and (3) curing: keeping the temperature at 145 ℃ for 25 min;

pre-burning: keeping the temperature for 2 hours at 285 ℃;

post-firing: and (3) preserving the heat for 4.5 hours at the temperature of 750 ℃ to obtain a heat-preservation filler precursor, wherein holes with the diameter of 50-100 micrometers and the length of 50-200 micrometers are uniformly distributed in the heat-preservation filler precursor.

(S.5) treating the heat-preservation filler precursor with supercritical carbon dioxide to obtain a finished product of the steel slag-based heat-preservation filler, wherein the pressure of the supercritical carbon dioxide treatment is 20MPa, the temperature is 40 ℃, and the supercritical treatment time is 1.5 h.

Application example 1

According to the weight parts, 250 parts of portland cement, 800 parts of the steel slag-based heat-insulating filler prepared in the example 2, 650 parts of sand and 200 parts of water are uniformly mixed, and then pouring is carried out to obtain the concrete block.

Application example 2

According to the weight parts, 250 parts of portland cement, 800 parts of the steel slag-based heat-insulating filler prepared in example 1, 650 parts of sand and 200 parts of water are uniformly mixed, and then pouring is carried out, so as to obtain the concrete block.

Comparative application example 1

According to the weight parts, 250 parts of Portland cement, 800 parts of the steel slag-based heat-preservation filler precursor which is not treated by the prepared supercritical carbon dioxide in the embodiment 2, 650 parts of sand and 200 parts of water are uniformly mixed and poured to obtain the concrete block.

Comparative application example 2

According to the weight portion, 250 portions of Portland cement, 800 portions of pebbles, 650 portions of sand and 200 portions of water are uniformly mixed and poured to obtain the concrete block.

The concrete blocks prepared in application examples 1-2 and comparative application examples 1-2 were tested, wherein:

1. coefficient of thermal conductivity: concrete prepared in each example and each proportion is poured into a mold with the size of 30cm multiplied by 5cm, the mold is placed in a standard curing room with the temperature of 20 +/-2 ℃ and the humidity of more than 95 percent for curing for 28 days, 10 samples prepared in each example 1-3 and each sample prepared in each proportion are measured according to GB/T10294-2008 'method for measuring and protecting heat plate of steady-state thermal resistance of heat-insulating material and relevant characteristics', the test temperature is 25 ℃, the environment is kept in a dry state to avoid the influence of the humidity on the heat conductivity coefficient of the concrete, the cold plate temperature is 25 ℃, the hot plate temperature is 35 ℃, the cold and hot plate temperature gradient is 10k, and the test results of 10 samples in each example or each proportion are averaged.

2. Compressive strength: the detection is carried out according to GB/T50081-2002 standard of test methods for mechanical properties of common concrete.

3. Breaking strength: the detection is carried out according to GB/T50081-2002 standard of test methods for mechanical properties of common concrete.

The test data are shown in the following table:

from the data in the table, we find that the particle size of the thermal insulation filler has a certain influence on the thermal conductivity, compressive strength and flexural strength of the concrete by comparing application example 1 with application example 2. The principle is that the larger the particles of the heat-insulating filler are, the more the number of holes contained in the heat-insulating filler is, so that the heat-insulating property of the heat-insulating filler is more excellent. Meanwhile, the large particles can serve as aggregate to reinforce the skeleton of the concrete, so that the mechanical strength of the application example 1 is improved to a certain extent.

Comparing application example 1 with comparative application example 1, the steel slag-based heat preservation filler precursor in comparative application example 1 is not subjected to carbon dioxide supercritical treatment, so that the components such as calcium oxide, magnesium oxide and the like in the precursor are not carbonized, the structural strength of the precursor is low, and the mechanical property in comparative application example 1 is the worst of several samples. Meanwhile, the calcium oxide, the magnesium oxide and other components inside the heat insulation board can react, expand and gel under the action of water, so that the inner holes of the heat insulation board can be damaged, and the heat insulation effect of the heat insulation board is obviously reduced, but the inner holes of the heat insulation board cannot be completely damaged after the heat insulation board reacts with the water, so that the heat insulation board still has a certain heat insulation effect compared with the heat insulation board in comparative application example 2.

Comparing the application example 1 with the comparative application example 2, we find that the mechanical properties of the application example 1 and the comparative application example 2 are relatively close, so that the heat-insulating filler in the invention can completely replace stones used as aggregates in the comparative application example 2, and cannot influence the mechanical properties of concrete. However, it can be seen from the thermal conductivity data that the thermal conductivity of the heat insulating filler of the present invention is greatly reduced by replacing the stone with the heat insulating filler, so that the heat insulating filler has more excellent heat insulating effect and more excellent green energy saving effect.