CN-118324452-B - Sodium citrate retarding alkali-activated slag geopolymer and preparation method and application thereof

Abstract

The application discloses a sodium citrate retarding alkali-activated slag geopolymer and a preparation method and application thereof, and the sodium citrate retarding alkali-activated slag geopolymer comprises raw materials of 926-1153 parts of a cementing material, 416-448 parts of an alkali-activated agent, 280-306 parts of water and 8-16 parts of sodium citrate, wherein the cementing material is obtained by mixing slag and wollastonite in a mass ratio of (7-9): 1 for modification treatment. The alkali-activated slag geopolymer prepared by the method can not only effectively prolong the coagulation time, but also improve the strength of the alkali-activated slag geopolymer, effectively balance the working performance and the mechanical performance, and break through the technical bottleneck of the application of the alkali-activated slag geopolymer in high-performance building materials. The obtained sodium citrate retarding alkali-activated slag polymer has the setting time of more than 15min, the compressive strength of 7 days of more than or equal to 90MPa, simple preparation process and good application prospect, and can be applied to high-performance building materials.

Inventors

• Fu Huanchang
• WU YANHAI
• LI LENGXUE

Assignees

• 广州理工学院

Dates

Publication Date

20260505

Application Date

20240301

Claims (6)

1. 1. The sodium citrate retarding alkali-activated slag geopolymer is characterized by comprising, by weight, 926-1153 parts of a cementing material, 416-448 parts of an alkali-activated agent, 280-306 parts of water and 8-16 parts of sodium citrate; The cementing material is prepared by mixing slag and wollastonite with a mass ratio of (7-9) 1, wherein the modification treatment comprises the steps of adding slag and wollastonite into a magnetic stirrer, stirring, heating, adding a composite modifier, continuously stirring, carrying out suction filtration, and drying, wherein the composite modifier is prepared by mixing sodium stearate and zinc stearate with a mass ratio of (1-5) 1-7, and the addition amount of the composite modifier is 0.5-3% of the mass of the cementing material; the alkali excitant is Na 2 O·nSiO 2 , the modulus n is the mass ratio of SiO 2 to Na 2 O in the solution, and the modulus n is conventionally selected to be 1-1.75.
2. 2. The sodium citrate retarding alkali activated slag polymer of claim 1, wherein the sodium citrate is used in an amount of 0.1% -2.5% by mass of the cementitious material.
3. 3. The sodium citrate retarded alkali activated slag polymer according to claim 2, wherein the stirring treatment speed is 50-150 r/min, the time is 45-60 min, and the temperature is 72-78 ℃.
4. 4. The sodium citrate retarded alkali activated slag polymer according to claim 2, wherein the continuous stirring time is 20 min-30 min and the temperature is 70 ℃ to 80 ℃.
5. 5. A method for preparing a sodium citrate retarded alkali activated slag geopolymer, characterized in that the method is used for preparing the sodium citrate retarded alkali activated slag geopolymer according to any one of claims 1 to 4, and the method comprises the following steps: S1, fully mixing a cementing material and sodium citrate, and uniformly stirring for 120-180S to obtain a powder mixture; s2, mixing an alkali excitant with water, and fully stirring for 30-60S to obtain a transparent clear solution; And S3, pouring the transparent clear solution into the powder mixture, and fully stirring for 2-3 min to obtain the sodium citrate retarding alkali-activated slag polymer.
6. 6. The application of the sodium citrate retarding alkali activated slag geopolymer, which is characterized in that the sodium citrate retarding alkali activated slag geopolymer according to claim 1 is used as a building material in the field of construction, wherein the building material is a raw material and/or a semi-finished product material and/or a finished product material.

Description

Sodium citrate retarding alkali-activated slag geopolymer and preparation method and application thereof Technical Field The invention relates to the technical field of building materials, in particular to a sodium citrate retarding alkali-activated slag geopolymer and a preparation method and application thereof. Background Alkali-activated geopolymers (geopolymers) are widely studied and popularized as substitutes for ordinary portland cements. The material rich in calcium, silicon and aluminum can be used as a raw material (precursor) for preparing the geopolymer, so that the alkali-activated geopolymer can absorb a large amount of solid waste, has excellent low-carbon benefit and cost benefit, and is a novel green inorganic cementing material. Blast furnace slag (slag) is A typical high-calcium precursor, forms A dense C-A-S-H gel under alkali silicate-activated systems (NaOH and NA 2O·nSiO2 mixed), and has excellent mechanical strength. Moreover, in order to meet engineering requirements, the strength of the alkali-activated slag polymer is further improved by reducing the water-cement ratio, so that the alkali-activated slag polymer meets the strength requirement of the alkali-activated slag polymer as a high-performance building material (such as a base material of alkali-activated ultra-high-performance concrete). However, alkali-activated slag polymers, although excellent in strength, have the limitation of rapid solidification, which greatly restricts their popularization and application in practical engineering. This problem is particularly pronounced after the water-to-gel ratio is reduced. Compatible chemical retarders are used in the prior art to alleviate the problem of rapid setting, such as lignin, sugars, phosphates, etc., but these chemical retarders are commonly used in conventional portland cements and are poorly effective in geopolymers. Even with potential heavy metal contamination problems. In addition, conventional retarders retard setting time by depleting calcium ions into other phases than the C-A-S-H gel. The use of this type of retarder can have some impact on strength. How to delay the alkali to excite the slag polymer and realize the balance of the working performance and the mechanical performance is the key for popularizing the novel polymer material application. Disclosure of Invention The invention aims to provide a sodium citrate retarding alkali-activated slag geopolymer and a preparation method and application thereof, which are used for solving the problems that the alkali-activated slag geopolymer prepared in the prior art cannot balance and retard solidification and is mechanical. In order to achieve the aim, the sodium citrate retarding alkali-activated slag polymer provided by the invention comprises, by weight, 926-1153 parts of cementing materials, 416-448 parts of alkali-activated agents, 280-306 parts of water and 8-16 parts of sodium citrate; The cementing material is prepared by mixing slag with wollastonite according to the mass ratio of (7-9): 1 and modifying the slag; the alkali excitant is Na 2O·nSiO2, the modulus n is the mass ratio of SiO 2 to Na 2 O in the solution, and the modulus n is conventionally selected to be 1-1.75. Further, the dosage of the sodium citrate is 0.1-2.5% of the mass of the cementing material. Further, the modification treatment is that slag and wollastonite are added into a magnetic stirrer, stirred and heated, and a composite modifier is added for continuous stirring, suction filtration treatment and drying treatment. Further, the composite modifier is obtained by mixing sodium stearate and zinc stearate in a mass ratio of (1-5) (1-7). Further, the stirring treatment speed is 50 r/min-150 r/min, the stirring treatment time is 45 min-60 min, and the stirring treatment temperature is 72-78 ℃. Further, the continuous stirring time is 20-30 min, and the temperature is 70-80 ℃. Further, the addition amount of the composite modifier is 0.5-3% of the mass of the cementing material. In addition, the invention also provides a preparation method of the sodium citrate retarding alkali-activated slag geopolymer, which comprises the following steps: S1, fully mixing a cementing material and sodium citrate, and uniformly stirring for 120-180 s to obtain a powder mixture; S2, mixing an alkali excitant with water, and fully stirring for 30-60 s to obtain a transparent clear solution; s3, pouring the transparent clear solution into the powder mixture, and fully stirring for 2-3 min to obtain the sodium citrate retarding alkali-activated slag geopolymer. The application also provides application of the sodium citrate retarding alkali-activated slag geopolymer, which is used as a building material in the field of construction, wherein the building material is a raw material and/or a semi-finished product material and/or a finished product material. Compared with the prior art, the method has the beneficial effects that sodium stearate and zinc st