CN-122010458-A - High-doping phosphogypsum curing agent and application thereof

CN122010458ACN 122010458 ACN122010458 ACN 122010458ACN-122010458-A

Abstract

The invention provides a high-doping phosphogypsum curing agent and application thereof, and belongs to the technical field of curing agents. The curing agent comprises polymer synergistic liquid, a hydrophobic modifier, a coagulant and an alkaline stabilizer, wherein the polymer synergistic liquid comprises sodium polyacrylate and polyvinyl acetate emulsion, the hydrophobic modifier comprises dimethyl tetrachlorodisilane, trimethyl trichlorodisilane and an organic solvent, the coagulant comprises sodium aluminate and sodium silicate, and the alkaline stabilizer comprises sodium hydroxide and polyaluminium chloride powder. According to the invention, through the synergistic effect of the four components, on the premise that the phosphogypsum doping amount is more than or equal to 90%, the early mechanical property, the water stability and the curing capability to harmful elements of the phosphogypsum-based road material are obviously improved. The invention not only consumes a great deal of industrial solid waste phosphogypsum and reduces environmental pollution, but also provides reliable technical support for the green, high-value and large-scale application of phosphogypsum.

Inventors

LIN KANG
YIN YUAN
Cheng Shufan
WU FEI
ZENG WEIXIN

Assignees

湖北省路桥集团有限公司

Dates

Publication Date: 20260512
Application Date: 20260128

Claims (10)

1. The high-doping phosphogypsum curing agent is characterized by comprising polymer synergistic liquid, a hydrophobic modifier, a coagulant and an alkaline stabilizer in a mass ratio of 1-4:2-6:1-4:2-6.
2. The high-doping phosphogypsum curing agent of claim 1, wherein the polymer synergistic liquid comprises sodium polyacrylate, polyvinyl acetate emulsion and water in a mass ratio of 6-9:3-6:85-91.
3. The high-doping phosphogypsum curing agent of claim 1, wherein the hydrophobic modifier comprises dimethyl tetrachlorodisilane, trimethyl trichlorodisilane and an organic solvent in a mass ratio of 5-8:3-5:12-26.
4. The high-doping phosphogypsum curing agent of claim 1, wherein the accelerator comprises sodium aluminate, sodium silicate and water in a mass ratio of 6-9:2-4:87-92.
5. The high-doping phosphogypsum curing agent of claim 1, wherein the alkaline stabilizer comprises sodium hydroxide, polyaluminum chloride powder and water in a mass ratio of 5-8:3-6:86-92.
6. The high-doping phosphogypsum curing agent of claim 1, wherein the mass ratio of the polymer synergistic liquid, the hydrophobic modifier, the accelerator and the alkaline stabilizer is 2:3:2:3.
7. The application of the high-doping phosphogypsum curing agent in any one of claims 1-6 in preparing the high-doping phosphogypsum aggregate-free road base material, which is characterized by comprising the following steps: s1, uniformly stirring and mixing undisturbed phosphogypsum and cement to obtain a first mixture; S2, atomizing the polymer synergistic liquid, spraying the atomized polymer synergistic liquid into the first mixture, and uniformly stirring and mixing the sprayed polymer synergistic liquid to obtain a second mixture; s3, sequentially atomizing the coagulant and the alkaline stabilizer, spraying the atomized coagulant and the atomized alkaline stabilizer into the second mixture, and uniformly stirring and mixing to obtain a third mixture; and S4, adding the hydrophobic modifier into the third mixture, and stirring and mixing uniformly to obtain the high-doping-amount aggregate-free phosphogypsum road base material.
8. The method according to claim 7, wherein the stirring speed in the step S1 is 20-30rpm, and the stirring time is 2-3min.
9. The method of claim 7, wherein the stirring speed of steps S2 and S3 is 150-250rpm, and stirring is continued for 3-5min after spraying.
10. The method according to claim 7, wherein the stirring speed in the step S4 is not less than 300rpm, and the hydrophobic modifier is continuously stirred for 2-3min after being added.

Description

High-doping phosphogypsum curing agent and application thereof Technical Field The invention relates to the field of curing agents, in particular to a high-doping phosphogypsum curing agent and application thereof. Background Phosphogypsum is an industrial byproduct gypsum discharged in the wet-process phosphoric acid production process, and the main component of phosphogypsum is calcium sulfate dihydrate (CaSO 4·2H2 O) and contains a small amount of impurities such as phosphorus, fluorine and the like. Because of the lack of an efficient and economic recycling path, the main treatment mode of phosphogypsum is stockpiling at present, so that a large amount of land resources are occupied, and the risk of infiltration pollution exists. As the stockpiling continues to grow and the comprehensive utilization level is limited, phosphogypsum has become a prominent environmental problem restricting the green development of the phosphorus chemical industry. In recent years, research on phosphogypsum resource utilization is in progress, and application of phosphogypsum is expanded to the fields of building materials, chemical industry, agriculture, environmental functional materials and the like. The phosphogypsum is used for road base construction, and is one of important directions for realizing large-scale resource utilization of the phosphogypsum. Especially, the phosphogypsum base layer structure with large doping amount and no aggregate (the phosphogypsum content is more than or equal to 90 percent) has great potential due to large phosphogypsum consumption and low cost. However, the application of the phosphogypsum as a cementing base material is challenged by impurities in the phosphogypsum, which can seriously delay the hydration of cement, so that the key problems are that (1) the retarding effect is obvious, the early strength is low, soluble phosphorus and other impurities form a coating layer on the surface of cement particles, the hydration of cement is seriously inhibited, the early strength development of base materials is slow, the construction progress requirement cannot be met, (2) the water resistance of the phosphogypsum hydration product is poor, the impurities delay the formation of a compact hydration product, the softening coefficient is low, the strength is greatly attenuated after meeting water, and (3) the environmental risk is prominent, the secondary pollution to underground water and surrounding soil is possibly caused under the condition of long-term service or rainwater leaching, and the large-scale application of the phosphogypsum with large doping amount in road engineering is seriously limited by the problems. In the prior art, many attempts have been made to improve the performance of phosphogypsum base materials by means of composite modification. Patent CN119241197A discloses a modified phosphogypsum cement stabilizing material, a preparation method and application thereof, which consists of phosphogypsum, cement, sodium silicate, slaked lime and water, wherein the mass ratio of phosphogypsum to cement is 85-95:5-15, the material performance is improved to a certain extent, but the 7d unconfined compressive strength is only 3.8-4.7MPa, the 14d and 28d strength increases limitedly, the higher requirements of a high-grade highway base layer on early strength and long-term bearing capacity are difficult to meet, systematic harmful element leaching concentration test data are not provided, and the pollution risk of the phosphogypsum under the long-term service or rainwater leaching condition cannot be clarified. Patent CN112125630A discloses a high-doped phosphogypsum-based stable material and application thereof in road base, which adopts 64-74% of original phosphogypsum, 13-20% of slag, 7-13% of cement and a composite modifier consisting of calcium chloride, petroleum coke desulfurization ash, bentonite, talcum powder and casein, wherein the unconfined compressive strength of 21d is up to 4.12MPa, the leaching concentration of fluorine and phosphorus is obviously reduced, but the synchronous curing effect of various heavy metals (such as chromium, lead, cadmium, arsenic and mercury) is not systematically examined, and the leaching condition of harmful elements in a complex environment still needs to be further verified. In summary, the prior art has obvious defects in the aspects of early strength development, long-acting water stability guarantee, multi-pollutant cooperative curing and the like. Therefore, development of a novel high-doping phosphogypsum aggregate-free base material capable of realizing early strength, high water stability and low pollution simultaneously is needed to be developed, and the novel high-doping phosphogypsum aggregate-free base material has important practical significance. Disclosure of Invention The main purpose of the invention is to provide a high-doping phosphogypsum curing agent and application thereof, which solves the problems in the backgrou