Expansion type phosphogypsum-based all-solid-waste shield synchronous grouting material and preparation method thereof

Abstract

The invention discloses an intumescent phosphogypsum-based all-solid waste shield synchronous grouting material, which is prepared from the following components in parts by weight: 40 to 60 parts of modified phosphogypsum, 1 to 5 parts of solid waste-based building gypsum, 20 to 30 parts of silicon-aluminum-based solid waste materials, 5 to 20 parts of silicon-aluminum exciting agents, 1 to 5 parts of nanometer modifying agents, 0.005 to 0.05 part of polycarboxylic acid-based mud-resistant rheological additives, 150 to 200 parts of shield tailings and 25 to 35 parts of water. The modified ardealite is obtained by sequentially carrying out water washing, neutralization, mechanical activation, surface modification and maintenance on ardealite. According to the invention, the activity and early strength of phosphogypsum can be effectively excited, the hydration reaction process of the mortar material is regulated and controlled synchronously, and the improved effects of hydration self-expansion, stable increase of early strength and later strength, controllable setting time and the like of the grouting material are realized; high value-added resource utilization of various industrial solid wastes can be realized, and the applicability is wide.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building materials, and particularly relates to an expanded phosphogypsum-based full-solid-waste shield synchronous grouting material and a preparation method thereof. BACKGROUND

[0002] Traditional synchronous grouting materials rely on cement-based systems, which have problems such as high cost and large carbon emissions. At the same time, there are problems such as slow setting, low early strength, large shrinkage, and excessive alkalinity, which make it difficult to meet the requirements of rapid construction and environmental protection of shield synchronous grouting. In recent years, although the research on solid waste substitution has increased, the solid waste content is generally less than 30%, and there are problems such as high bleeding rate and difficult to control the setting time. Phosphogypsum is a by-product of the wet-process phosphoric acid process, and has problems such as large emission and large total amount of storage. Existing phosphogypsum resource utilization technologies mainly focus on preparing cement retarder, artificial aggregate and road subgrade material, but the product added value is generally low.

[0003] At present, there are some reports on the application of phosphogypsum in synchronous grouting materials, such as: patent CN104609814B discloses a high specific gravity low consistency water dispersion resistant synchronous grouting material, which replaces the traditional grouting material river sand and bentonite with shield mud sand, and uses shield mud sand and machine-made sand as fine aggregate. Patent application CN117209241A discloses a low-strength synchronous grouting material prepared from earth pressure shield muck, and its preparation method and application, which uses cement, steel slag powder, phosphogypsum, earth pressure shield muck, construction waste recycled fine aggregate, alum, early strength agent and tackifier as raw materials of the grouting material. Although the above-mentioned scheme uses shield muck, construction waste recycled fine aggregate and phosphogypsum as raw materials, the obtained grouting material has low strength, which is difficult to meet the requirements of high-quality engineering, and the high content of solid waste also leads to the difficulty in maintaining the stability of the performance of the grouting material, which brings great risk to large-scale engineering application. Patent application CN117185759A discloses a synchronous grouting material for shield tunnel in coastal areas, which comprises the following raw materials in parts by weight: cement 20-40 parts, steel slag powder 10-25 parts, shield muck 80-120 parts, phosphogypsum 15-35 parts, unrefined sea sand 120-150 parts, early strength agent 4-6 parts, conditioning agent 1-3 parts, and mixing water 100-125 parts. However, the real-time water content of each batch of shield muck needs to be quickly and accurately measured during construction, and the amount of additional water needs to be immediately adjusted. This puts high requirements on the on-site quality control system, and may affect the performance of the grouting material due to errors. Patent application CN117383869A uses multi-source solid waste A component and modified composite activator B component to generate a full-solid waste low-carbon environment-friendly grouting material containing phosphogypsum through rapid polymerization reaction. The use of composite activator greatly improves the adverse effects of solid waste raw materials on the performance of grouting material, but the rapid polymerization reaction between the raw material components makes the setting time of the grouting material uncontrollable, which may cause risks during long-distance transportation and use. SUMMARY

[0004] The main purpose of the present application is to solve the problems and deficiencies of the prior art, and to provide an expanded phosphogypsum-based full-solid waste synchronous grouting material for shield tunnel, which uses a variety of industrial solid wastes as main raw materials, utilizes nano-modified agent and polycarboxylic acid anti-mud rheological additive, and combines the synergistic effect of alkali active material dissolution and modified agent, to effectively activate the activity and early strength of phosphogypsum, control the hydration reaction process of synchronous mortar material, realize the improved effects of hydration self-expansion, early strength, stable growth of late strength, controllable setting time of grouting material, and facilitate the control of slurry pH value.

[0005] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows: An expanded phosphogypsum-based full-solid-waste shield synchronous grouting material, each component and the weight percentage it accounts for include: modified phosphogypsum 40-60 parts (free of calcination pretreatment), solid-waste-based building gypsum 1-5 parts, silicon-aluminum-based solid-waste material 20-30 parts, silicon-aluminum activator 5-20 parts, nano modifier 1-5 parts, polycarboxylic acid-based anti-mud rheological additive 0.005-0.05 parts, shield tailings 150-200 parts, and water 25-35 parts; the modified phosphogypsum is obtained by sequentially washing, neutralizing, mechanically activating, surface modifying, and curing the phosphogypsum.

[0006] In the above scheme, the main component of the phosphogypsum is CaSO4·2H2O, and the leaching experiment shows that the pH value is 4.0-5.0, and the appearance is light gray or dark gray.

[0007] Further, in the preparation step of the modified phosphogypsum, calcium carbide slag (doping amount 3-5%) is introduced in the neutralization step to promote the conversion of residual acidic substances (such as P2O5, F - ) into inert calcium phosphate and calcium fluoride; and nanoparticles (such as silicon dioxide or nano-aluminum dioxide) are introduced in the surface modification step to reduce the agglomeration effect of the original phosphogypsum particles, improve the fluidity of the synchronous mortar slurry, form a high-molecular water-blocking film on the surface of the AFt crystal, and inhibit the expansion of the water.

[0008] Still further, the specific preparation steps of the modified phosphogypsum include the following: 1) Impurity separation and neutralization treatment Water washing and impurity removal: mix the original phosphogypsum with water (mass ratio of original phosphogypsum to water 1:2.5-3.5) and stir for 10-15 min to remove soluble phosphorus, fluorine, and organic matter (waste water needs to be recycled and treated), and repeat the washing until the pH value of the filtrate is stable at 5.5-6.5; Neutralization and modification: add calcium carbide slag (doping amount 3-5% of the mass of the wet phosphogypsum) to the obtained wet phosphogypsum, and stir for 30-45 min to promote the conversion of residual acidic substances (such as P2O5, F - ) into inert calcium phosphate and calcium fluoride; 2) Mechanical activation and surface modification Crushing and refining: the washed phosphogypsum is subjected to pressure filtration and dewatering (moisture content ≤15%), and crushing treatment, so that the particle size of the crushed phosphogypsum meets the requirements of 100% passing rate through a 2.36 mm square hole sieve and more than 90% passing rate through a 1.18 mm square hole sieve, thereby effectively destroying the crystal inclusion structure and improving the reactivity; Surface modification: Add nano-modifying agent (such as nano-silicon dioxide or nano-aluminum dioxide) to the crushed phosphogypsum (doping amount is 0.5-3% of the mass of the phosphogypsum), ball mill mixing (ball milling speed is 20-30 r / min, 30-50 min), reduce the agglomeration effect of the original phosphogypsum particles, improve the fluidity of the synchronous mortar slurry, form a high-molecular water-blocking film on the surface of the AFt crystal, and inhibit the expansion of the water. 3) Aging maintenance The surface-modified phosphogypsum is aged and maintained in a sealed environment for 7-10 days, and the recrystallization process is completed by adjusting the humidity (65-75% RH) and temperature (25-35°C), reducing the free water content to ≤10wt%.

[0009] In the above scheme, the solid waste-based building gypsum can be selected from one or more of phosphorus building gypsum, desulfurization building gypsum, and building gypsum.

[0010] Further, the main component of the solid waste-based building gypsum is CaSO4·0.5H2O, and the mass fraction of β-type hemihydrate gypsum should be not less than 60%.

[0011] Further, the main impurities of desulfurization building gypsum are CaCO3 and CaSO3, with a content of about 10-20wt%; the main impurities of phosphorus building gypsum are P2O5 (0.5-5%) and fluoride (content about 0.3%); the main impurities of building gypsum are Fe2O3 and TiO2; the appearance and microstructure are slightly different according to the type.

[0012] In the above scheme, the silicon-aluminum-based solid waste material can be selected from one or more of fly ash, slag powder, and steel slag powder.

[0013] Further, in the fly ash, the total content of SiO2+Al2O3+Fe2O3 is ≥50%, the loss on ignition is ≤8.0%, the sieve residue of 45μm square hole sieve is ≤25%, and the strength activity index is ≥70%; in the slag powder, the total content of CaO+SiO2+MgO is ≥66.7%, the glass content is ≥85%, the specific surface area is ≥400m 2 / kg, and the strength activity index is ≥95%; the specific surface area of the steel slag powder is ≥400m 2 / kg, and the strength activity index is ≥80%.

[0014] In the above scheme, the silicon-aluminum activator can be selected from at least one of carbide slag, red mud, and kiln dust.

[0015] Further, the Ca(OH)2 content in the carbide slag is >65wt% (dry basis), the pH value is strongly alkaline (12-13), and the specific surface area is ≥400m 2 / kg, 80μm square mesh sieve residue ≤5%; the red mud must be fully dried and scattered before use, and can only be used in low dosage. The specific surface area of the kiln dust is 500~1000m 2 / kg, can only be used as a trace component, with a dosage of no more than 5wt%.

[0016] In the above scheme, the nano modifier can be selected from nano silicon dioxide or nano aluminum dioxide, etc.

[0017] Further, the particle size range of the nano silicon dioxide or nano aluminum dioxide inorganic modifier can be selected from 10~50nm, wherein 10~30nm is better, and 30~50nm is the most economical.

[0018] In the above scheme, the components of the polycarboxylic acid anti-mud rheological additive include anti-mud polycarboxylic acid water reducer mother liquor, polydimethyl diallyl ammonium chloride, glucose, cationic starch ether, alkyl polyglucoside, polyvinyl methyl ether, welan gum and hydroxypropyl methyl cellulose.

[0019] Further, in the polycarboxylic acid anti-mud rheological additive, the components and their weight fractions include: anti-mud polycarboxylic acid water reducer mother liquor 25~30 parts, polydimethyl diallyl ammonium chloride 1~2 parts, glucose 1~2 parts, cationic starch ether 2~4 parts, alkyl polyglucoside 0.5~1 part, polyvinyl methyl ether 0.5~1.5 parts, welan gum 0.1~0.3 parts, and hydroxypropyl methyl cellulose 0.2~0.5 parts.

[0020] Further, the solid content of the anti-mud polycarboxylic acid water reducer mother liquor is 50~60wt%.

[0021] Further, in the anti-mud polycarboxylic acid water reducer mother liquor, the structure general formula of the water reducing component is shown as formula I; I; In formula I, a is 2~4, b is 1~3, c is 2~5, d is 3~5, and n is 1~3.

[0022] Further, in the polycarboxylic acid anti-mud rheological additive, the introduced glucose competes with PCE molecules for adsorption on the active sites of clay particles by using its polyhydroxy structure, so that it can effectively act on the cement particles and fully exert its dispersion effect based on steric hindrance; at the same time, the glucose has the property of retarding setting, which can prevent the loss of fluidity and improve the slump retention, and together ensure the workability of the mortar under the condition of containing mud. The polydimethyl diallyl ammonium chloride reduces the electronegativity of the clay surface through the strong positive charge quaternary ammonium salt group on the molecular chain, forms a "shielding layer", and further effectively prevents the adsorption of clay on PCA, forming a more effective anti-mud component. The cationic starch ether plays a role in competitive adsorption and wrapping. The positively charged quaternary ammonium group on the molecular chain can preferentially and quickly adsorb on the surface of the clay particles in the shield tailings, forming a layer of cationic coating film; this layer of film can effectively "shield" the adsorption sites of the clay particles in the shield tailings, blocking the ineffective adsorption between the clay and the polycarboxylic acid water reducer mother liquor, so that the mother liquor can more fully act on the cement particles, ensuring the initial dispersibility; it can also play a steric hindrance enhancement role. The long-chain molecular structure can form a certain spatial hindrance around the clay particles after adsorption, further preventing the flocculation and aggregation of particles. In addition, the cationic starch ether can synergize with the tackifying component to improve the stability of the slurry and prevent segregation. The introduced alkyl polyglucoside can adsorb on the clay-water interface, reduce the interfacial energy, change the hydrophilicity of the clay, and make it change to hydrophobic, thereby inhibiting its hydration and dispersion; at the same time, the alkyl polyglucoside also has the functions of defoaming and lubrication, and has the wetting and dispersing functions of non-ionic surfactants, can improve the wrapping of the slurry on the aggregate, and can also eliminate the micro-bubbles that may be left by the shield foam agent, making the slurry structure more dense. Polyvinyl methyl ether has temperature responsiveness and dissolves in water at low temperature, playing a role in increasing viscosity; when the temperature of the slurry rises to near the critical solubility temperature (usually 30-40℃) due to hydration heat or environmental factors, the molecular chain dehydrates and shrinks, changes from an extended state to a curled state, and forms a microgel network structure in the solution. In addition, it can effectively lock water and stabilize. This in-situ formed three-dimensional network can greatly enhance the water retention capacity of the slurry, effectively prevent water evaporation and bleeding at high temperatures, which is particularly important for deep and long-distance shield construction. The added welan gum and hydroxypropyl methyl cellulose have a high viscosity-increasing effect. The rigid helical molecular chain can form a high-strength network structure in water, providing high pseudoplasticity and significant thixotropy. The network structure can effectively suspend heavy particles and prevent sedimentation and segregation, ensuring uniformity of the slurry components. In addition, it has good salt resistance and compatibility: it can still maintain stable performance in the high ionic strength tailings environment and has good compatibility with other chemical admixtures.

[0023] In the above scheme, the 1.18mm square hole sieve residue of the shield tailings is ≤5%, and the mud content is ≤10wt%.

[0024] The application further provides a preparation method of the phosphogypsum-based full-solid-waste shield synchronous grouting material, and the method comprises the following steps: dry mixing the weighed modified phosphogypsum, solid-waste-based building gypsum, silicon-aluminum-based solid-waste material and silicon-aluminum activator according to the proportioning; adding a nano modifier, a polycarboxylic acid anti-mud rheological additive, shield tailings and water, and stirring until the slurry fluidity reaches the working performance requirement.

[0025] Further, the slurry fluidity is greater than or equal to 200 mm.

[0026] Further, the phosphogypsum-based full-solid-waste shield synchronous grouting material is poured, vibrated to remove bubbles and cured at constant temperature and humidity to obtain a phosphogypsum-based test piece.

[0027] Further, the curing at constant temperature and humidity is performed at a temperature of 18-22 DEG C and a relative humidity of not less than 50%.

[0028] Further, the curing at constant temperature and humidity is performed for more than 24 h.

[0029] According to the above scheme, the phosphogypsum-based full-solid-waste shield synchronous grouting material has an initial setting time of 2-4 h, an expansion rate controlled in a range of 0.02-0.15%, a 1d compressive strength greater than or equal to 1 MPa, a 28d compressive strength greater than or equal to 8 MPa, a bleeding rate less than or equal to 5% and a water-land strength ratio greater than or equal to 80%.

[0030] The principles of the application include: (1) Micro-expansion property control technology: SO4 2- generated by the reaction of the dissolved phosphogypsum with C3A in the cementitious material, the micro-expansion amount is accurately controlled, the expansion rate is controlled in a range of 0.02-0.10%, the expansion property of the phosphogypsum-based shield synchronous mortar is utilized to effectively compensate the material shrinkage, reduce the shield construction gap, prevent the segment from floating and avoid the waste of a large amount of secondary grouting material, thereby effectively saving the amount of secondary grouting and saving the material cost; meanwhile, the nano modifier introduced in the surface modification process can simultaneously have a filling effect and a crystal nucleus effect, which is beneficial to the generation of a large amount of C-S-H gel and the filling of pores and reduction of shrinkage.

[0031] (2) "raw material quality control-pre-mixing-interfacial modification" three-step processing method of raw materials: first, the pre-modification means of washing-phosphogypsum-neutralization-mechanical activation-surface modification and curing are carried out on the phosphogypsum, and the particle size and moisture content of solid waste-based building gypsum, silicon-aluminum-based solid waste materials, silicon-aluminum activator and other raw materials are pre-mixed to improve the mixing uniformity of the raw materials; on this basis, further combined with nano-modifier and polycarboxylic acid anti-mud rheological additive, nano-particles fill the pores between the hydration products of phosphogypsum, making the structure more dense, while generating additional hydration products, and can be used as crystal nucleus to optimize crystal lapping; under the condition of stirring, the introduction of polycarboxylic acid anti-mud rheological additive makes the nano-modifier preferentially adsorbed on the surface of solid waste particles such as phosphogypsum to form a core-shell structure, promotes the directional growth of hydration products in the interfacial zone, and improves the interfacial bonding strength; Breakthrough the traditional grouting material's dependence on bentonite and organic ether-based tackifier, solve the technical bottleneck of poor cohesion and poor cohesion of phosphogypsum, complex adjustment of slurry performance, effectively meet the requirements of fluidity, consistency and underwater dispersion resistance.

[0032] Calcium sulphoaluminate-gypsum composite activation mechanism and alkaline self-activation mechanism: SO4 2- react with active Al2O3 in steel slag, slag powder and fly ash to form ettringite (AFt) as the main strength framework, and the AFt phase can account for 35-50%, replacing the traditional C-S-H gel system; in addition, the pozzolanic activity of steel slag, slag powder and fly ash and other materials is utilized to form a pH controllable alkaline environment through industrial solid waste-based silicon-aluminum activator such as red mud, carbide slag or kiln dust, to activate SiO2 and Al2O3 in fly ash glass to generate calcium aluminate gel products to fill pores and promote the formation of a dense and stable overall structure.

[0033] Compared with the prior art, the present application has the following beneficial effects: 1) A full-solid waste raw material system is adopted to establish a multi-component solid waste system based on "phosphogypsum + solid waste-based building gypsum + silicon-aluminum-based solid waste material + silicon-aluminum activator", achieving an industrial solid waste utilization rate of ≥95%, which has important economic and environmental benefits; the introduction of alkaline silicon-aluminum activator such as carbide slag stabilizes the pH value of the system in the ideal range of 11.5-12.5, while accelerating the AFt phase generation rate and inhibiting the problem of uncontrolled expansion; 2) Directional expansion control of dihydrate gypsum crystals and ettringite crystals: beta-type semi-hydrated building gypsum is selected as one of the raw materials, which interweaves into a network structure when it generates dihydrate gypsum crystals, forming 0.02-0.10% micro-expansion to avoid shrinkage and cracking; and through precise reaction of SO4 2- with active aluminum in cementitious materials, needle-like ettringite (AFt) crystal network structure is formed; silicon-aluminum-based solid waste materials are used as aluminum source core carriers to utilize the Al3+ SO4 dissolved with phosphogypsum 2- In combination, the AFt phase with three-dimensional expansion effect is generated under the action of alkaline activator, and the narrow control of the expansion amount of 0.02-0.10% is promoted to be achieved.

[0034] 3) A mechanical-chemical composite activation process is used for the phosphogypsum: the phosphogypsum is pre-broken and the particle size is controlled, and a nano-modified material is further added to modify the surface of the phosphogypsum; the mixing amount of the phosphogypsum in the grouting material is significantly improved, and can be broken through to 40% and above, which is much higher than the upper limit of 20% of the prior art.

[0035] 4) Hydration regulation technology innovation: (1) a double-parameter regulation model is established: the SiO2 / Al2O3 molar ratio is controlled in the range of 2.8-3.2, and the CaO / SO3 molar ratio is optimized to the range of 1.5-1.8; (2) a phosphogypsum modified geopolymer composite cementitious material system is developed: the rapid generation of N-A-S-H and C-A-S-H and other geopolymer products can effectively inhibit the excessive generation of ettringite in the early stage, and the stable performance of the sulfate activation under low alkalinity conditions will effectively promote the development of the late strength; (3) an ettringite directional generation technology is innovated, and the length-diameter ratio of ettringite is controlled in the range of 20-30 through seed induction, and the uniformity is improved by 40%.

[0036] 5) Precise regulation of rheological properties: a rheological parameter control system is constructed: the yield stress is ≤25 Pa, the plastic viscosity is 0.35-0.55 Pa·s, and the thixotropic index is 2.2-2.8.

[0037] 6) Durability improvement: (1) anti-permeation enhancement technology; promote the formation of a relatively dense C-S-H gel network; (2) sulfate resistance technology: introduce steel slag powder, slag powder, fly ash and other silicon-aluminum active materials to consume free Ca(OH)2 and form a dense ettringite wrapping layer; (3) carbonization resistance technology: use the characteristics of phosphogypsum to regulate the pore solution pH to ≤12.0, and generate nano-hydrated products to effectively fill micro-cracks. DETAILED DESCRIPTION

[0038] In order to more clearly understand the purposes, technical solutions and beneficial effects of the present application, the present application will be described in detail in conjunction with specific embodiments.

[0039] In the following examples, the main component of the phosphogypsum used is CaSO4·2H2O, and the leaching experiment shows that the pH value is 4.0-5.0; the passing rate of 2.36 mm square hole screen is 100%, the passing rate of 1.18 mm square hole screen is more than 90%, the gypsum content is >90%, and the crystallinity is >85%.

[0040] The main component of the solid waste-based building gypsum used is CaSO4·0.5H2O; the mass fraction of β-type hemihydrate gypsum is not less than 60%.

[0041] The specific surface area of the steel slag powder used is 400m 2 / kg, and the strength activity index is 80%. The fly ash is grade II ash, the total content of SiO2+Al2O3+Fe2O3 is 50%, the loss on ignition is 8.0%, the 45μm square hole sieve residue is 25%, and the strength activity index is 70%.

[0042] In the slag powder, the total content of CaO+SiO2+MgO is 66.7%, the glass content is 85%, the specific surface area is 400m 2 / kg, and the strength activity index is 95% The preparation method of the polycarboxylic acid anti-mud rheological additive used is as follows: 2 parts of polydimethyl diallyl ammonium chloride, 1 part of glucose monohydrate, 3 parts of cationic starch ether, 1 part of alkyl polyglucoside, 1 part of polyvinyl methyl ether, 0.2 parts of Welan gum (FT11) and 0.3 parts of hydroxypropyl methyl cellulose (100,000 viscosity) are added into 30 parts of anti-mud polycarboxylic acid water reducer mother liquor to stir uniformly to obtain the polycarboxylic acid anti-mud rheological additive; wherein the anti-mud polycarboxylic acid water reducer mother liquor used is selected from the polycarboxylic acid water reducer mother liquor JJ-PC30 provided by Hubei Lianjian New Material Co., Ltd., and the effective solid content is 50%.

[0043] The 1.18mm square hole sieve residue of the shield tailings is ≤5%, and the clay content is ≤10wt%.

[0044] The modified phosphogypsum is obtained by washing, neutralizing, mechanical activation, surface modification and curing of phosphogypsum, and the specific preparation method comprises the following steps: 1) Impurity separation and neutralization treatment Water washing and impurity removal: mix and stir the original phosphogypsum with water at a mass ratio of 1:3 for not less than 4min, and repeat the washing until the pH value of the filtrate is stable at not less than 6; Neutralization and modification: add carbide slag (doping amount is 10% of the mass of the wet phosphogypsum) into the obtained wet phosphogypsum, and stir for 10min.

[0045] 2) Mechanical activation and surface modification Grinding and crushing and refining: the washed phosphogypsum is subjected to pressure filtration dehydration (moisture content ≤15%), and then is subjected to crushing treatment, and the particle size of the crushed phosphogypsum satisfies: 2.36mm square hole sieve passing rate is 100%, and 1.18mm square hole sieve passing rate is more than 90%; Surface modification: add nano silicon dioxide (doping amount is 3% of the mass of the phosphogypsum) into the crushed phosphogypsum and stir uniformly.

[0046] 3) Aging and homogenization curing The surface-modified phosphogypsum is aged in a closed environment for 3 days, and a recrystallization process is completed by regulating humidity (65-75% RH) and temperature (25-35°C) to reduce the free water content to less than or equal to 10 wt%.

[0047] Example 1 A phosphogypsum-based full-solid-waste shield synchronous grouting material, the raw material ratio (mass parts) is: modified phosphogypsum 50 parts, phosphorus building gypsum 2 parts, fly ash 20 parts, steel slag powder 10 parts, carbide slag 15 parts, nano silicon dioxide 3 parts, shield tailings 200 parts, polycarboxylic acid anti-mud rheological additive 0.03 parts, water 30 parts. The preparation method of the grouting material comprises the following steps: The modified phosphogypsum, fly ash, steel slag, carbide slag, and phosphorus building gypsum are weighed and added to a stirring pot, stirred for 120 s to mix uniformly, and then the weighed water, polycarboxylic acid anti-mud rheological additive, nano silicon dioxide, and shield tailings are added to the stirring pot and stirred for 3 min to form a uniformly mixed slurry with a flow degree of more than 200 mm.

[0048] The obtained slurry is further poured into a 40 mm x 40 mm x 160 mm triple mold, vibrated on a vibration table to eliminate air bubbles generated during stirring, and the surface is scraped flat with a scraper, and placed in a constant temperature and humidity curing box (20±2℃, relative humidity above 50%) for curing, and after 1d, the phosphogypsum-based full-solid-waste test piece is demolded.

[0049] Performance test: The performance test results of the phosphogypsum-based full-solid-waste shield synchronous grouting material and test piece prepared in this example are shown in Table 1, and the related physical and mechanical properties and environmental protection indicators meet the requirements of the specification standards.

[0050] Table 1 Performance test results of the phosphogypsum-based shield synchronous grouting material obtained in Example 1

[0051] Example 2 A phosphogypsum-based full-solid-waste shield synchronous grouting material, the raw material ratio (mass parts) is: phosphogypsum 55 parts, desulfurization building gypsum 3 parts, blast furnace slag powder 25 parts, red mud 10 parts, carbide slag 10 parts, nano aluminum dioxide 2 parts, shield tailings 180 parts, polycarboxylic acid-based anti-mud rheological additive 0.05 parts, water 28 parts.

[0052] The preparation method of the grouting material comprises the following steps: The weighed dry materials (modified phosphogypsum, blast furnace slag, red mud, carbide slag, desulfurization building gypsum) are added into a stirring pot and stirred for 120s to uniformly mix them, and then the weighed water, polycarboxylic acid anti-mud rheological additive, nano silicon dioxide and shield tailings are added into the stirring pot and stirred for 3min to form a uniformly mixed slurry, and the fluidity thereof should be above 200mm; The obtained slurry is poured into a triple mold of 40mmx40mmx160mm, the bubbles generated in the stirring process are eliminated by a vibration table, and the surface is flattened using a scraper, and then placed into a constant temperature and humidity curing box for curing, and after 1d, the phosphogypsum-based full solid waste shield synchronous grouting material is demolded.

[0053] The performance indexes of the phosphogypsum-based full solid waste shield synchronous grouting material and the test piece prepared in this example are shown in Table 2, and the related physical and mechanical properties and environmental protection indexes meet the requirements of the specification standards.

[0054] Table 2 Performance test results of the phosphogypsum-based shield synchronous grouting material obtained in Example 2

[0055] Example 3 A phosphogypsum-based full solid waste shield synchronous grouting material, the raw material ratio (mass parts) is: modified phosphogypsum 45 parts, blast furnace building gypsum 2.5 parts, blast furnace slag powder 30 parts, red mud 10 parts, carbide slag 10 parts, nano aluminum dioxide 1.5 parts, shield tailings 200 parts, polycarboxylic acid-based anti-mud rheological additive 0.03 parts, water 26 parts; The preparation method of the grouting material comprises the following steps: The weighed dry materials (modified phosphogypsum, blast furnace slag, red mud, carbide slag, blast furnace building gypsum) are added into a stirring pot and stirred for 120s to uniformly mix them, and then the weighed water, polycarboxylic acid anti-mud rheological additive, nano silicon dioxide and shield tailings are added into the stirring pot and stirred for 3min, and the fluidity thereof should be above 220mm; The obtained slurry is poured into a triple mold of 40mmx40mmx160mm, the bubbles generated in the stirring process are eliminated by a vibration table, and the surface is flattened using a scraper, and then placed into a constant temperature and humidity curing box for curing, and after 1d, the phosphogypsum-based full solid waste shield synchronous grouting material is demolded.

[0056] Performance test: The performance test results of the phosphogypsum-based full solid waste shield synchronous grouting material and the test piece prepared in this example are shown in Table 3, and the related physical and mechanical properties and environmental protection indexes meet the requirements of the specification standards.

[0057] Table 3 Performance test results of the phosphogypsum-based shield synchronous grouting material obtained in Example 3

[0058] Example 4 A phosphogypsum-based full-solid waste shield synchronous grouting material, the raw material ratio (mass parts) is: modified phosphogypsum 50 parts, phospho building gypsum 3 parts, steel slag powder 25 parts, kiln dust 5 parts, carbide slag 5 parts, nano silicon dioxide 3 parts, polycarboxylic acid-based anti-mud rheological additive 0.02 parts, water 30 parts; The preparation method of the grouting material comprises the following steps: The weighed dry materials (modified phosphogypsum, phospho building gypsum, steel slag powder, carbide slag, kiln dust) are added to the stirring pot and stirred for 120s to uniformly mix them, and then the weighed water, polycarboxylic acid anti-mud rheological additive, nano silicon dioxide and shield tailings are added to the stirring pot and stirred for 3min, and the fluidity should be above 230mm.

[0059] The obtained slurry is poured into a 40mm×40mm×160mm triple mold, the bubbles generated during stirring are eliminated by a vibration table, and a scraper is used to scrape the surface flat, and then it is placed into a constant temperature and humidity curing box for curing, and after 1d, it is demolded to form a phosphogypsum-based full-solid waste shield synchronous grouting material.

[0060] The performance test results of the phosphogypsum-based full-solid waste shield synchronous grouting material and the test piece prepared in this example are shown in Table 4, and the related physical and mechanical properties and environmental protection indicators meet the requirements of the specification standards.

[0061] Table 4 Performance test results of the phosphogypsum-based shield synchronous grouting material obtained in Example 4

[0062] In Example 4, the steel slag provides the silicon-aluminum component, the kiln dust and the carbide slag supplement the alkali excitation source to form a stable ettringite network. The addition of building waste powder can replace part of the aggregate to reduce the density of the material, the nano silicon dioxide is used to improve the interfacial bonding force and improve the water resistance, the polycarboxylic acid anti-mud rheological additive is used to reduce the loss of fluidity over time and improve the fluidity, and the three are compounded to have a synergistic effect. Compared with Example 1, the water-land strength ratio can be further improved, compared with Example 2, the loss of fluidity over time can be reduced, and compared with Example 3, the consistency is higher. The phosphogypsum-based shield synchronous grouting material obtained in Example 4 exhibits good durability and mechanical properties.

[0063] Comparative Example 1 An expanded phosphogypsum-based full-solid waste shield synchronous grouting material, the raw material ratio (mass parts) is: modified phosphogypsum 50 parts, phosphorus building gypsum 2 parts, fly ash 20 parts, steel slag powder 10 parts, carbide slag 15 parts, nano silicon dioxide 3 parts, shield tailings 200 parts, anti-mud polycarboxylic acid water reducer mother liquor (same above, provided by Hubei Lianjian New Material Co., Ltd., JJ-PC30 type) 0.03 parts, slow-release anti-slump agent (MH-BT-201) 0.01 parts, calcium-based bentonite 2 parts, and water 30 parts; The preparation method of the grouting material comprises the following steps: The weighed phosphogypsum, fly ash and carbide slag are added to the stirring pot, stirred for 120s to mix uniformly, and then the weighed water, polycarboxylic acid high-performance water reducing agent, nano silicon dioxide and shield tailings are added to the stirred mixture and stirred for 3min to form a uniformly mixed slurry, and the fluidity thereof should be above 200mm.

[0064] The obtained slurry is poured into a 40mm*40mm*160mm triple mold, the bubbles generated during stirring are eliminated by a vibration table, and the surface is scraped flat with a scraper, and then placed in a constant temperature and humidity curing box for curing, demolded after 1d to form a phosphogypsum-based full-solid waste test piece.

[0065] The performance test results of the phosphogypsum-based full-solid waste shield synchronous grouting material and test piece prepared in Comparative Example 1 are shown in Table 5.

[0066] Table 5 Performance test results of the phosphogypsum-based shield synchronous grouting material and test piece obtained in Comparative Example 1

[0067] Comparative Example 2 An expanded phosphogypsum-based full-solid waste shield synchronous grouting material, the raw material ratio (mass parts) is: raw phosphogypsum 50 parts, fly ash 20 parts, steel slag powder 10 parts, carbide slag 15 parts, phosphorus building gypsum 2 parts, nano silicon dioxide 3 parts, shield tailings 200 parts, polycarboxylic acid anti-mud rheological additive 0.03 parts, and water 25 parts.

[0068] The preparation method of the grouting material comprises the following steps: The weighed phosphogypsum, fly ash, steel slag, carbide slag and phosphorus building gypsum are added to the stirring pot, stirred for 120s to mix uniformly, and then the weighed water, polycarboxylic acid high-performance water reducing agent, nano silicon dioxide and shield tailings are added to the stirred mixture and stirred for 3min to form a uniformly mixed slurry, and the fluidity thereof should be above 200mm.

[0069] The obtained slurry was poured into a 40mmx40mmx160mm triple mold, the bubbles generated in the slurry during stirring were eliminated by a vibration table, the surface was scraped flat using a scraper, and was placed into a constant temperature and humidity curing box for curing, and was demolded after 1d to form a phosphogypsum-based full solid waste test piece.

[0070] The performance indicators of the phosphogypsum-based full solid waste synchronous grouting material prepared in Comparative Example 2 and time are shown in Table 6.

[0071] Table 6 Performance test results of the phosphogypsum-based synchronous grouting material obtained in Comparative Example 2

[0072] Comparative Example 3 An expanded phosphogypsum-based full solid waste synchronous grouting material, the preparation method of which is substantially the same as that of Example 1, with the difference that the preparation method of the modified phosphogypsum comprises the following steps: The raw phosphogypsum was mixed with water (the mass ratio of raw phosphogypsum to water was 1:3) and stirred for 10-15min, 0.5% ammonia water solution was added, the phosphogypsum was added into the solution in a mass ratio of 1:2 and continuously stirred for 10min, and was placed for 20min, the impurities floating on the water surface were scraped off and filtered, and then the phosphogypsum was placed in a (45±5) ℃ oven for drying to constant mass. After drying, the phosphogypsum was placed in a ball mill for crushing treatment. After crushing, the particle size of the phosphogypsum needed to meet: 2.36mm square hole sieve passing rate 100%, 1.18mm square hole sieve passing rate more than 90%. Nano silicon dioxide (doping amount 3% of the mass of the phosphogypsum) was added to the crushed phosphogypsum and stirred uniformly; and the modified phosphogypsum was obtained after standing for 3d.

[0073] The obtained slurry was poured into a 40mmx40mmx160mm triple mold, the bubbles generated in the slurry during stirring were eliminated by a vibration table, the surface was scraped flat using a scraper, and was placed into a constant temperature and humidity curing box for curing, and was demolded after 1d to form a phosphogypsum-based full solid waste test piece.

[0074] The performance indicators of the phosphogypsum-based full solid waste synchronous grouting material prepared in Comparative Example 3 and time are shown in Table 7.

[0075] Table 7 Performance test results of the phosphogypsum-based synchronous grouting material obtained in Comparative Example 3

[0076] The above describes the embodiments of the present application, but the present application is not limited to the above-described specific embodiments, and the above-described specific embodiments are only illustrative but not restrictive, and those skilled in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, which all belong to the protection of the present application.

Claims

1. An expanded phosphogypsum-based full-solid-waste shield synchronous grouting material, characterized in that, The components and the weight percentage of each component include: modified phosphogypsum 40-60 parts, solid waste-based building gypsum 1-5 parts, silicon-aluminum-based solid waste material 20-30 parts, silicon-aluminum activator 5-20 parts, nano modifier 1-5 parts, polycarboxylic acid-based anti-mud rheological additive 0.005-0.05 parts, shield tailings 150-200 parts, and water 25-35 parts; the modified phosphogypsum is obtained by sequentially washing, neutralizing, mechanically activating, surface modifying and curing the phosphogypsum.

2. The expanded phosphogypsum-based full-solid-waste shield synchronous grouting material according to claim 1, characterized in that, The solid waste-based building gypsum is one or more of phosphorus building gypsum, desulfurization building gypsum and building gypsum; the main component is CaSO4·0.5H2O, and the mass fraction of β-type hemihydrate gypsum is not less than 60%.

3. The expanded phosphogypsum-based full-solid-waste shield synchronous grouting material according to claim 1, characterized in that, The silicon-aluminum-based solid waste material is one or more of fly ash, slag powder and steel slag powder.

4. The expanded phosphogypsum-based full-solid-waste shield synchronous grouting material according to claim 1, characterized in that, The silicon-aluminum activator is at least one of carbide slag, red mud and kiln dust.

5. The expanded phosphogypsum-based full-solid-waste shield synchronous grouting material according to claim 1, characterized in that, The nano modifier is nano silicon dioxide or nano aluminum dioxide.

6. The expanded phosphogypsum-based full-solid-waste shield synchronous grouting material according to claim 1, characterized in that, The components of the polycarboxylic acid anti-mud rheological additive include anti-mud polycarboxylic acid water reducer mother liquor, polydimethyl diallyl ammonium chloride, glucose, cationic starch ether, alkyl polyglucoside, polyvinyl methyl ether, welan gum and hydroxypropyl methyl cellulose.

7. The expanded phosphogypsum-based full-solid-waste shield synchronous grouting material according to claim 6, characterized in that, In the polycarboxylic acid anti-mud rheological additive, the components and the weight percentage of each component include: anti-mud polycarboxylic acid water reducer mother liquor 25-30 parts, polydimethyl diallyl ammonium chloride 1-2 parts, glucose 1-2 parts, cationic starch ether 2-4 parts, alkyl polyglucoside 0.5-1 part, polyvinyl methyl ether 0.5-1.5 parts, welan gum 0.1-0.3 parts, and hydroxypropyl methyl cellulose 0.2-0.5 parts.

8. The expanded phosphogypsum-based full-solid-waste shield synchronous grouting material according to claim 1, characterized in that, The 1.18mm square hole sieve residue of the shield tailings is ≤5%, and the clay content is ≤10wt%.

9. The method for preparing the expanded phosphogypsum-based full-solid-waste shield synchronous grouting material according to any one of claims 1-8, characterized in that, The method comprises the following steps: dry mixing the weighed modified phosphogypsum, solid waste-based building gypsum, silicon-aluminum-based solid waste material and silicon-aluminum activator according to the proportion; adding the nano modifier, polycarboxylic acid anti-mud rheological additive, shield tailings and water, and stirring until the slurry flowability reaches the working performance requirement.

10. The method of claim 9, wherein, The slurry flowability is ≥200mm.

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