CN114873948B

CN114873948B - Preparation and application method of dispersing agent

Info

Publication number: CN114873948B
Application number: CN202210750921.4A
Authority: CN
Inventors: 雷英强; 龚英; 周继中; 吴伟; 李凤玉; 李晓华
Original assignee: Sinohydro Bureau 7 Co Ltd
Current assignee: Sinohydro Bureau 7 Co Ltd
Priority date: 2022-06-28
Filing date: 2022-06-28
Publication date: 2023-04-07
Anticipated expiration: 2042-06-28
Also published as: CN114873948A

Abstract

The invention discloses a preparation and application method of a dispersing agent, which collects carbon dioxide and silica fume discharged by a ferrosilicon plant and forms slurry to be used as a cement admixture, thereby not only completing the closed-loop treatment of wastes at a production end, but also reducing the cement consumption in building materials and improving the strength and durability of concrete or mortar.

Description

Preparation and application method of dispersing agent

Technical Field

The invention relates to the technical field of concrete materials, in particular to a preparation method and an application method of a dispersing agent.

Background

With the growing concern of human beings on the environment, reducing carbon dioxide emissions is a world-wide effort and must be accomplished. From the perspective of greening of building material industry, reducing the use amount of cement and realizing high performance of concrete are powerful means for realizing greening of building materials. The silica fume collected from the ferrosilicon plant can improve the strength and durability of concrete while reducing the amount of cement used (see documents 1 and 2). The traditional method is to directly collect the silica fume particles by a dry method, and carbon dioxide is finally discharged into the atmosphere and has no economic benefit even if collected. Meanwhile, the particle size (D50 =5 μm) of the silica fume is very small, the silica fume has very high surface energy, the actual particle size is increased due to the existence of agglomeration, and the activity of the silica fume cannot be fully exerted when the silica fume is directly used as an admixture. CN112225503A (see document 3) mentions the use of various small-molecule alcohol ether dispersants to improve silica fume dispersibility for improving activity. CN202110028249 (refer to document 4) adopts calcium nitrate and ultrasonic method to prepare silica fume dispersion liquid to improve activity. The above patents all adopt dispersing agent to disperse and dry the silica fume directly or by combining with physical energy to prepare suspension to solve the problem of silica fume agglomeration and improve the reaction activity of the silica fume. The adopted technology only disperses finished product silica fume, and does not concern the carbon dioxide generated by producing the silica fume; the dispersing agents only play a role in solving agglomeration, but the dispersion system can only realize short-time stabilization, and the silica fume slurry can only be prepared at present.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation and application method of a dispersing agent, which is used for producing high-dispersion micron calcium carbonate with a filling and compacting effect on a cement system from carbon dioxide discharged from a ferrosilicon plant and also comprises high-dispersion silicon dioxide and calcium silicate hydrate. The mixed slurry is used as a cement admixture for building materials such as concrete, mortar and the like, so that the cement consumption is reduced, and the strength and the durability are improved.

The purpose of the invention is realized by the following technical scheme:

the dispersing agent is characterized by being prepared from the following raw materials in parts by weight: 72-76 parts of isobutylene alcohol polyoxyethylene ether, 3-4 parts of maleic anhydride, 0.01-0.1 part of azodiisobutyronitrile, 1-1.5 parts of hydrogen peroxide, 0.5-2 parts of a benzene-containing monomer with unsaturated double bonds, 50-70 parts of deionized water, a material A and a material B; the material A is prepared from the following raw materials in parts by weight: 5-11 parts of acrylic acid, 1-4 parts of acrylic ester-containing monomer and 18-22 parts of deionized water; the material B is prepared from the following raw materials in parts by weight: 0.08-0.12 part of L-ascorbic acid, 0.3-0.5 part of thioglycolic acid and 18-22 parts of deionized water.

Further, the unsaturated double bond containing benzene monomer is any one of styrene, styrene sodium sulfonate and benzyl acrylate. Styrene is preferably used.

Further, the acrylic ester-containing monomer is any one of methyl acrylate, ethyl acrylate, propyl acrylate and butyl acrylate. Methyl acrylate is preferably used.

Further, the molecular weight of the isobutenol polyoxyethylene ether is more than 4000Dalton. Preferably 6000Dalton Methyleneoxide Ether is used.

The preparation method of the dispersant is characterized by comprising the following steps:

s1, dissolving isobutenol polyoxyethylene ether, maleic anhydride, hydrogen peroxide and azodiisobutyronitrile into deionized water, uniformly stirring, and heating to 30-45 ℃ to obtain a first mixture;

s2, dissolving acrylic acid and acrylic acid ester-containing monomers into deionized water and fully stirring to prepare a material A;

s3, dissolving the L-ascorbic acid and the mercaptoacetic acid in deionized water, and fully stirring to prepare a material B;

s4, adding a benzene-containing monomer with unsaturated double bonds into the first mixture, and respectively dripping the material A and the material B into the first mixture of 10-15 Zhong Houxiang for 2.5-3 hours and dripping the material B for 3-3.5 hours;

s5, keeping the temperature of the mixture and reacting for 1-1.5 hours to obtain the macromolecular copolymerization dispersant.

The application method of the dispersant is characterized by comprising the following steps:

a01, adding 90-110 parts of deionized water into a collection tank, introducing 0.2-0.4 part of calcium hydroxide powder, controlling the stirring speed to be more than 700rpm, and adding 0.1-1 part of dispersant;

a02, introducing gas containing carbon dioxide and silicon elements into the collection pool, monitoring the pH value, adding calcium hydroxide, and maintaining the pH =10-12;

a03, adjusting the rate of tail gas entering a collecting tank, and maintaining the mol ratio of CaO to SiO2 in the tank at 1.2-1.5;

and A04, finishing collection when the mass fraction of the solid matters in the collection pool is 20-40%, controlling the temperature of the collection pool to be 25-40 ℃, stirring at the speed of more than 700rpm, adding 0.1-1 part of stabilizer, and stirring for 5-7 hours under heat preservation to obtain the slurry concrete admixture.

Furthermore, the particle fineness of the calcium hydroxide powder is more than 300 meshes. The use of calcium hydroxide particles of 500 mesh is recommended.

Further, the PH value was always maintained at 12.

Further, the stabilizer is one or more of xanthan gum, arabic gum, hydroxypropyl cellulose and hydroxyethyl cellulose in any proportion according to the product. Preferably, a mass ratio of xanthan gum to hydroxyethylcellulose 1:1 composite product is used.

Further, the viscosity of the stabilizer aqueous solvent is 400-600cps. A 500cps viscosity is recommended.

The beneficial effects of the invention are:

(1) The dispersant prepared by the invention and the calcium-silicon ratio (molar ratio) in the collection process are controlled to collect the ferrosilicon tail gas and the powder, so that the carbon dioxide emission can be reduced, the pozzolanic dispersibility is improved, the pozzolanic activity is fully exerted, and the micron calcium carbonate particles with filling effect are prepared.

(2) The dispersant is a comb-type anionic polymer, has long side chains (> 4000 Dalton), can form organic-inorganic clusters, and provides multipoint crystal generation, and formed calcium carbonate crystals are adsorbed by anions to prevent unlimited growth, so that the D50 of calcium carbonate is 10 mu m, and the D10 is 0.1 mu m.

(3) The dispersant can adjust the hydrophilic and lipophilic values, so that the particles adsorbed by the dispersant in an aqueous solution are loosely (Loop) adsorbed, the distance between the particles is larger, and the suspension stability of the particles can be better maintained.

(4) In the preparation process of the concrete admixture, the calcium-silicon ratio is controlled, the surface of the siliceous material can be slightly etched, and the reactivity of the siliceous material is further improved. Meanwhile, the dissolved silicon source can form a small amount of nano-scale calcium silicate hydrate product under the conditions of controlling the calcium-silicon ratio and a specific dispersant, which can accelerate the hydration rate of tricalcium silicate in a cement system and make up for the problem of early strength reduction after the cement consumption is reduced.

(5) The dispersant of the invention has the advantages that: firstly, maleic anhydride with a fixed proportion is adopted, and the adsorption capacity of the maleic anhydride to volcanic ash is higher than that of carboxylic acid. If the phosphate group is used as an adsorption group, although the adsorption capacity can also be improved, the product can be used as an admixture and added into concrete, the setting time is greatly prolonged, and the early strength is reduced; benzene ring and hydroxyl ester are introduced into a molecular chain, and after the target hydrophilic and oleophylic value is regulated and controlled, the molecular chain is adsorbed on the surface of particles to cause the change of the hydrophilic and oleophylic value of the particles, so that the suspension capacity of the particles is enhanced, which is different from a pure hydrophilic dispersant; finally, the hydrophobic groups are not polymerized by emulsion, that is, emulsifier is not introduced, and soap-free polymerization is adopted, so that the emulsifier can cause the final product to be added into concrete as admixture, the air content is increased, and the durability and the mechanical property are reduced.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.

The invention provides a technical scheme that:

example 1

A preparation method of a dispersing agent capable of recovering carbon dioxide to prepare a high-dispersity slurry concrete admixture comprises the following steps:

s1, premelting 72 parts of isobutylene alcohol polyoxyethylene ether, 3 parts of maleic anhydride and 1 part of hydrogen peroxide, 0.01 part of azodiisobutyronitrile and 60 parts of deionized water, introducing the mixture into the bottom of a reaction kettle, stirring uniformly, and heating to 45 ℃;

s2, adding 2 parts of styrene, respectively dropwise adding a material A (11 parts of acrylic acid, 4 parts of methyl acrylate and 20 parts of deionized water while stirring dropwise) and a material B (0.12 part of L-ascorbic acid, 0.5 part of thioglycolic acid and 20 parts of deionized water while stirring dropwise) after 15 minutes, completing dropwise adding of the material A for 3 hours, and completing dropwise adding of the material B for 3.5 hours;

and S3, keeping the temperature for reaction for 1.5 hours, and adding deionized water for dilution until the solid content is 40% to obtain the dispersing agent-1.

Further, the molecular weight of the methacryloxypropylene ether was 6000Dalton.

Example 2

s1, premelting 76 parts of isobutylene alcohol polyoxyethylene ether, 4 parts of maleic anhydride, 1.5 parts of hydrogen peroxide, 0.1 part of azodiisobutyronitrile and 60 parts of deionized water, introducing the mixture into the bottom of a reaction kettle, uniformly stirring, and heating to 45 ℃;

s2, adding 2 parts of styrene, and after 15 minutes, respectively dropwise adding a material A (11 parts of acrylic acid, 4 parts of methyl acrylate and 20 parts of deionized water while dropwise adding and stirring) and a material B (0.12 part of L-ascorbic acid, 0.5 part of thioglycolic acid and 20 parts of deionized water while dropwise adding and stirring), wherein the material A is dropwise added for 3 hours, and the material B is dropwise added for 3.5 hours;

and S3, keeping the temperature for reaction for 1.5 hours, and adding deionized water for dilution until the solid content is 40% to obtain the dispersing agent-2.

Further, the molecular weight of the isobutylene alcohol polyoxyethylene ether is 6000Dalton.

Example 3

s1, premelting 74 parts of isobutylene alcohol polyoxyethylene ether, 3 parts of maleic anhydride, 1.2 parts of hydrogen peroxide, 0.05 part of azodiisobutyronitrile and 50 parts of deionized water, introducing the mixture into the bottom of a reaction kettle, uniformly stirring, and heating to 30 ℃;

s2, adding 0.5 part of sodium styrene sulfonate, dropwise adding a material A (5 parts of acrylic acid, 1 part of methyl acrylate and 18 parts of deionized water while stirring) and a material B (0.08 part of L-ascorbic acid, 0.3 part of thioglycolic acid and 18 parts of deionized water while stirring) after 10 minutes, completing dropwise adding of the material A for 2.5 hours, and completing dropwise adding of the material B for 3 hours;

and S3, keeping the temperature for reaction for 1 hour, and adding deionized water for dilution until the solid content is 40% to obtain the dispersant-3.

Further, the molecular weight of the isobutylene alcohol polyoxyethylene ether was 5000Dalton.

Example 4

s1, premelting 75 parts of isobutylene alcohol polyoxyethylene ether, 3 parts of maleic anhydride, 1.3 parts of hydrogen peroxide, 0.07 part of azodiisobutyronitrile and 70 parts of deionized water, introducing the mixture into the bottom of a reaction kettle, uniformly stirring, and heating to 35 ℃;

s2, adding 0.5 part of benzyl acrylate, respectively dropwise adding a material A (8 parts of acrylic acid, 2 parts of methyl acrylate and 22 parts of deionized water while dropwise adding and stirring) and a material B (0.1 part of L-ascorbic acid, 0.4 part of thioglycolic acid and 22 parts of deionized water while dropwise adding and stirring) after 10 minutes, completing dropwise adding of the material A for 2.7 hours, and completing dropwise adding of the material B for 3.3 hours;

and S3, keeping the temperature for reaction for 1.3 hours, and adding deionized water for dilution until the solid content is 40% to obtain a dispersing agent-4.

Further, the molecular weight of the methacryloxypropylene ether was 7000Dalton.

Example 5

An application method of a dispersing agent for preparing a high-dispersity slurry concrete admixture by recycling carbon dioxide comprises the following steps:

a01, 100 parts of deionized water was added to a collection tank equipped with a high-speed stirrer, followed by 0.3 part of calcium hydroxide powder. The stirring speed was controlled at 1000rpm, and 0.1 part of dispersant-1 prepared in example 1 was added;

a02, introducing tail gas produced by a ferrosilicon plant into a collection pool, monitoring the pH value, adding calcium hydroxide to adjust the pH value, and keeping the pH value =12 all the time;

a03, adjusting the rate of tail gas entering a collecting tank, and ensuring that the molar ratio of CaO to SiO2 in the tank is kept at 1.2;

and A04, finishing collection when the mass fraction of the solid matters in the collection pool is within 40 percent, controlling the temperature of the collection pool to 30 ℃ by using the production waste heat of a ferrosilicon plant, keeping the stirring speed at 1000rpm, adding 0.1 part of stabilizer, and stirring for 6 hours under the condition of heat preservation to obtain the slurry concrete admixture.

Further, the stabilizer is a composite product of xanthan gum with 500cps viscosity and hydroxyethyl cellulose 1:1 by mass ratio.

Example 6

An application method of a dispersant for preparing a high-dispersity slurry concrete admixture by recycling carbon dioxide comprises the following steps:

a01, 100 parts of deionized water was added to a collection tank equipped with a high-speed stirrer, followed by 0.4 part of calcium hydroxide powder. Controlling the stirring speed to 1000rpm, and adding 1 part of dispersant-1 prepared in example 1;

a02, introducing tail gas produced by a ferrosilicon plant into a collecting pool, monitoring the pH value, adding calcium hydroxide to adjust the pH value, and keeping the pH value =12 all the time;

a03, adjusting the rate of tail gas entering a collecting tank, and ensuring that the molar ratio of CaO to SiO2 in the tank is kept at 1.5;

Example 7

a01, 100 parts of deionized water was added to a collection tank equipped with a high-speed stirrer, followed by 0.2 part of calcium hydroxide powder. The stirring speed was controlled at 1000rpm, and 0.1 part of dispersant-2 prepared in example 2 was added;

Example 8

a01, 90 parts of deionized water was added to a collection tank equipped with a high-speed stirrer, followed by addition of 0.3 part of calcium hydroxide powder. The stirring speed was controlled at 1000rpm, and 1 part of dispersant-2 prepared in example 2 was added;

Example 9

a01, 90 parts of deionized water was added to a collection tank equipped with a high-speed stirrer, followed by 0.2 part of calcium hydroxide powder. Controlling the stirring speed to 800rpm, and adding 0.4 part of dispersant-3 prepared in example 3;

a02, introducing tail gas produced by a ferrosilicon plant into a collection pool, monitoring the pH value, adding calcium hydroxide to adjust the pH value, and keeping the pH value =10 all the time;

a03, adjusting the rate of tail gas entering a collecting tank, and ensuring that the molar ratio of CaO to SiO2 in the tank is kept at 1.3;

and A04, finishing collection when the mass fraction of the solid matters in the collection pool is within 40 percent, controlling the temperature of the collection pool to 25 ℃ by using the production waste heat of a ferrosilicon plant, keeping the stirring speed at 800rpm, adding 0.5 part of stabilizer, and stirring for 5 hours under heat preservation to obtain the slurry concrete admixture.

Further, the stabilizer is 400cps viscosity hydroxypropyl cellulose.

Example 10

a01, 110 parts of deionized water was added to a collection tank equipped with a high-speed stirrer, followed by addition of 0.4 part of calcium hydroxide powder. Controlling the stirring speed to 1200rpm, and adding 0.8 part of dispersant-4 prepared in example 4;

a02, introducing tail gas produced by a ferrosilicon plant into a collecting pool, monitoring the pH value, adding calcium hydroxide to adjust the pH value, and keeping the pH value =11 all the time;

a03, adjusting the rate of tail gas entering a collecting tank, and ensuring that the molar ratio of CaO to SiO2 in the tank is kept at 1.4;

and A04, completing collection when the mass fraction of solid matters in the collection pool is within 40 percent, controlling the temperature of the collection pool to 40 ℃ by using the production waste heat of a ferrosilicon plant, keeping the stirring speed at 1200rpm, adding 0.8 part of stabilizer, and keeping the temperature and stirring for 7 hours to obtain the slurry concrete admixture.

Further, the stabilizer is 400cps viscosity xanthan gum.

Test material

Cement: the omei cement P.O 42.5.5 has the density =3.11g/cm3, the specific surface area =362m2/kg, the compressive strength 3d =24.9mpa and the compressive strength 28d =49.7mpa.

TABLE 1 Cement Components, expressed in mass percent

C3S[％]	C2S[％]	C3A[％]	C4AF[％]
				55.31	14.73	3.63	10.73

Sand: the artificial machine-made sand has the water absorption rate of 1.2 percent, the stone powder content of 16 percent and the apparent density of 2720kg/m3.

Stone: 5mm-20mm of artificial macadam, 0.3 percent of water absorption, 6 percent of needle sheet content and 2720kg/m3 of apparent density.

Silica fume: 92-grade semi-dense silica fume with growth of growth and new material.

Test data

According to GBT 27690-2011 silica fume for mortar and concrete, the patent example is compared with commercially available silica fume, the doping amount is 10% of the mass fraction of the total adhesive material, and the data of the patent example is as follows according to the conversion of solid content:

table 2 comparison of activity tests

As can be seen from Table 2, the activity of the slurry of the admixture prepared by the present patent is higher than the strength of the silica fume when compared with the activity of the commercial silica fume.

The concrete 28d compressive strength is detected according to the GB/T50081-2019 standard, and the concrete 28d seepage pressure resistance and the 28d electric flux are detected according to the GB/T50082-2009 standard.

TABLE 3 test C40 ratio [ kg/m3]

Water (W)	Cement	Sand	Stone (stone)	Fly ash	Silica fume
						164	268	802	1020	85.4	18.6

The mixing amount of the silica fume and the patent example is 5 percent of the total mass fraction of the cementing material, the patent example converts the solid content and deducts the water in the example, the mixing amount of the water reducing agent is adjusted to ensure that the expansion degree is 550 +/-10 mm, and the data is as follows:

table 4 concrete test data

Sample (I)	28d Strength [ MPa ]]	Electric flux [ C]	Anti-seepage device
				Silica fume	46.8	1245	P8 has no leakage
Example 5	49.1	1190	P8 has no leakage
				Example 6	47.2	1210	P8 has no leakage
Example 7	51.3	1150	P8 has no leakage
				Example 8	47.8	1220	P8 has no leakage
Example 9	52.0	1145	P8 has no leakage
				Example 10	48.5	1215	P8 has no leakage

The foregoing is illustrative of the preferred embodiments of this invention, and it is to be understood that the invention is not limited to the precise form disclosed herein and that various other combinations, modifications, and environments may be resorted to, falling within the scope of the concept as disclosed herein, either as described above or as apparent to those skilled in the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The application method of the dispersing agent is characterized by comprising the following steps:

a03, adjusting the rate of tail gas entering a collecting tank, and maintaining CaO to SiO in the tank ₂ The molar ratio is kept between 1.2 and 1.5;

a04, completing collection when the mass fraction of solid matters in the collection pool is 20-40%, controlling the temperature of the collection pool to be 25-40 ℃, stirring at the speed of more than 700rpm, adding 0.1-1 part of stabilizer, and stirring for 5-7 hours under heat preservation to obtain a slurry concrete admixture;

the dispersing agent is prepared from the following raw materials in parts by weight: 72-76 parts of isobutylene alcohol polyoxyethylene ether, 3-4 parts of maleic anhydride, 0.01-0.1 part of azobisisobutyronitrile, 1-1.5 parts of hydrogen peroxide, 0.5-2 parts of a benzene-containing monomer with unsaturated double bonds, 50-70 parts of deionized water, a material A and a material B; the material A is prepared from the following raw materials in parts by weight: 5-11 parts of acrylic acid, 1-4 parts of acrylic ester-containing monomer and 18-22 parts of deionized water; the material B is prepared from the following raw materials in parts by weight: 0.08-0.12 part of L-ascorbic acid, 0.3-0.5 part of thioglycolic acid and 18-22 parts of deionized water;

the preparation method of the dispersing agent is characterized by comprising the following steps:

s1, dissolving isobutenol polyoxyethylene ether, maleic anhydride, hydrogen peroxide and azobisisobutyronitrile into deionized water, uniformly stirring, and heating to 30-45 ℃ to obtain a first mixture;

2. A method of using a dispersant as claimed in claim 1, wherein: the particle fineness of the calcium hydroxide powder is more than 300 meshes.

3. A method of using a dispersant as claimed in claim 1, wherein: the pH value is 12.

4. A method of using a dispersant as claimed in claim 1, wherein: the stabilizer is at least one of xanthan gum, arabic gum, hydroxypropyl cellulose and hydroxyethyl cellulose.

5. A method of using a dispersant as claimed in claim 1, wherein: the viscosity of the stabilizer aqueous solvent is 400-600cps.

6. A method of using a dispersant as claimed in claim 1, wherein: the unsaturated double bond benzene-containing monomer is any one of styrene, styrene sodium sulfonate and benzyl acrylate.

7. A method of using a dispersant as claimed in claim 1, wherein: the acrylic acid ester-containing monomer is any one of methyl acrylate, ethyl acrylate, propyl acrylate and butyl acrylate.

8. A method of using a dispersant as claimed in claim 1, wherein: the molecular weight of the isobutenol polyoxyethylene ether is more than 4000Dalton.