Solid waste source high-activity powder slurry and preparation method thereof

Abstract

The present invention relates to the technical field of cement-based building materials, and in particular to a high-activity powder seat slurry derived from solid waste and a preparation method thereof. The present invention addresses the construction requirements of the seat slurry by first utilizing industrial solid waste to burn a high-activity powder material derived from a solid waste source, namely, sulfur-aluminum-iron. This powder is then compounded with Portland cement as the primary cementitious material. Furthermore, inorganic materials such as active mineral fine powder and limestone powder are added to the composite. Metakaolin and limestone powder are used to adjust the plasticity of the seat slurry to meet construction requirements. The resulting seat slurry exhibits controllable setting time, high mechanical strength, and thixotropic, plastic, and micro-expansion properties.

Description

Technical Field

[0001] The present invention relates to the technical field of cement-based building materials, and in particular to a high-activity powder slurry from solid waste sources and a preparation method thereof. Background Art

[0002] Sealing mortar is a specialized dry-mix mortar material composed of high-strength cement as the primary binder, fine aggregate, high-performance admixtures, and other functional materials. It is suitable for compartmentalization, sealing, or cushioning at joints in prefabricated components, as well as for the installation of mechanical equipment using the mortar method. Sealing mortar is currently being widely adopted due to its excellent properties, including ready-to-use properties such as good plasticity, early strength, high strength, minimal expansion, ease of construction, excellent water retention, and resistance to steel corrosion.

[0003] During the development of the national economy, a large amount of industrial solid waste and urban construction waste is generated due to mineral mining, urban renewal and transformation, etc. Therefore, rationally and economically developing the utilization value of industrial solid waste and construction waste, innovating their utilization methods and product forms, and developing them into high-end building materials industrialization can not only reduce environmental pollution but also further promote their resource utilization.

[0004] Currently, most research on seat mortars utilizes modified silicate and sulfoaluminate cements supplemented with admixtures and various modifiers. However, due to its long setting time, low early strength, and generally fluid nature, ordinary silicate cement alone struggles to meet the desired seat mortar properties, including plasticity, early strength, high strength, and micro-expansion. Furthermore, sulfoaluminate cement suffers from low production volume and high price, resulting in high seat mortar production costs. Furthermore, current research on the resource utilization of industrial solid waste is insufficiently comprehensive, primarily focusing on the production of hollow bricks for insulation boards from single industrial solid wastes. This results in low effective waste utilization and low added value for the resulting products. Some existing technologies utilize silica-alumina-based industrial solid waste to produce sulfoaluminate cement clinker for use in grouting, ultra-high performance concrete, 3D-printed concrete, and other technical fields, but these have yet to be applied to seat mortar products. The inventors conducted seat mortar tests using existing solid waste-based sulfoaluminate cement clinker and cement and found that these cements did not meet the required seat mortar construction performance requirements, limiting the production and application of industrial solid waste in seat mortars. Summary of the Invention

[0005] In order to overcome the problems existing in the prior art, the present invention aims at the construction requirements of the seat slurry. First, industrial solid waste is used to burn solid waste sources of sulfur-aluminum-iron high-activity powder materials, and the materials are compounded with silicate cement as the main cementitious material. At the same time, inorganic materials such as active mineral fine powder and limestone powder are added to form a multi-composite material. Kaolin and limestone powder are used to adjust the plasticity of the seat slurry to meet the construction requirements, and a seat slurry with controllable setting time, high mechanical strength, and thixotropic plastic micro-expansion properties is prepared.

[0006] Specifically, the solid waste source high-activity powder slurry of the present invention is composed of the following raw materials:

[0007] 60-120 parts of high-activity powder materials of sulfur-aluminum-iron series from solid waste sources;

[0008] 250-350 parts of Portland cement

[0009] 20-40 parts of silica fume;

[0010] 30-50 parts fly ash;

[0011] 15-25 parts of metakaolin;

[0012] 10-20 parts of limestone powder;

[0013] 450-550 parts of quartz sand;

[0014] 0.8-1.6 parts of water reducer;

[0015] Retarder 0.8-1.6 parts

[0016] 0.1-0.5 parts of cellulose ether;

[0017] 0.4-0.8 parts of redispersible latex powder;

[0018] Defoaming agent: 0.06-0.1 parts.

[0019] Preferably, the solid waste source sulfur-aluminum-iron high-activity powder material is prepared by drying, grinding, screening, and calcining washed fly ash, desulfurized gypsum, and aluminum ash to prepare an intermediate, and then mixing the intermediate with gypsum and grinding it. The main component is Ca4Al6O 12 SO4 and Ca2SiO4.

[0020] The solid waste source sulfur-aluminum-iron high-activity powder material of the present invention is prepared by designing and calculating the proportion of raw materials from washed fly ash, desulfurized gypsum, and aluminum ash, which are bulk industrial solid wastes, according to the principle of complementary combination. The main component is Ca4Al6O 12 SO4 and Ca2SiO4, and contains part of iron phase. Its strength development mechanism is similar to that of ordinary sulphoaluminate cement and rapid hardening high-iron sulphoaluminate cement, but its 1d and 28d compressive strengths are higher than those of ordinary sulphoaluminate cement and rapid hardening high-iron sulphoaluminate cement. Its preparation process can realize the fully automatic preparation of sulphur-aluminum-iron high-activity materials for a series of large-scale industrial solid wastes such as washed fly ash, desulfurization gypsum and aluminum ash through the linkage of four major functional zones, namely "raw material pretreatment zone", "solid-phase reaction zone", "product preparation zone" and "dynamic control zone", and at the same time realize the disposal of harmful elements such as Na and K in aluminum ash.

[0021] Preferably, the mass ratio of washed fly ash, desulfurized gypsum and aluminum ash is 32-38:35-40:25-30, the sieve mesh is 200 mesh, the calcination is kept at 1200-1300℃ for 20-40min, the mass ratio of intermediate to gypsum is 92-98:2-8, and the mixed powder is ground to a specific surface area of 400±10m 2 / kg.

[0022] Preferably, the solid waste source high-activity powder slurry is composed of the following raw materials:

[0023] 80 parts of high-activity powder materials of sulfur-aluminum-iron series from solid waste sources;

[0024] 320 parts of Portland cement;

[0025] 25 parts of silica fume;

[0026] 40 parts of fly ash;

[0027] 20 parts of metakaolin;

[0028] 15 parts of limestone powder;

[0029] 500 parts of quartz sand;

[0030] 1.2 parts of water reducer;

[0031] 1.2 parts of retarder;

[0032] 0.3 parts of cellulose ether;

[0033] 0.6 parts of redispersible latex powder;

[0034] 0.08 parts of defoaming agent.

[0035] Preferably, the silicate cement is 42.5 grade silicate cement.

[0036] Preferably, the silica fume specific surface area is ≥2000m 2 / kg, activity index 120%, has a strong volcanic ash effect, can undergo secondary hydration reaction with cement hydration product Ca(OH)2 to form cementitious products, fill the cement stone structure, improve the microstructure of the slurry, and enhance the mechanical properties and durability of the hardened body.

[0037] Preferably, the fly ash is Class I fly ash, which has finer particles, smaller aggregation of glass particles, and more individual glass microbeads, which is conducive to exerting the ball effect and volcanic ash activity.

[0038] Preferably, the limestone powder is obtained by further grinding the stone chips and stone powder produced during limestone crushing or production of machine-made sand to obtain a particle size of no more than 10 μm and a specific surface area of ≥

[0039] 500m2 / kg, fine powder with CaCO3 content ≥99%, is a new type of auxiliary cementitious material that is easy to obtain, high-quality and inexpensive. It can not only reduce costs, but also, due to the micro-aggregate effect, micro-crystal nucleus effect and specific chemical activity, limestone powder can fill the slurry pores, reduce the material hydration heat, improve the workability and fluidity of the slurry, increase the density and reduce the viscosity.

[0040] The metakaolin of the present invention is a white powder formed by calcining and dehydrating clay containing kaolinite at 500℃ to 900℃. Its main components are SiO2 and Al2O3, and it is a mineral material with volcanic ash activity. Adding a certain amount of metakaolin can participate in the hydration reaction of the slurry to generate hydrated calcium aluminate and CSH gel, promote the formation of calcium aluminoferrite with micro-expansion effect, reduce the early self-shrinkage of the slurry, etc., and the metakaolin particles are small, which can fill the voids in the slurry cement paste and increase the density of the slurry. The active ingredients therein react with Ca(OH)2 to generate gel products, which play a role in reducing porosity, refining pore size, and effectively preventing the diffusion of water molecules and the migration of harmful ions. In addition to the above-mentioned active factors, more importantly, due to the addition of a large amount of metakaolin in the present invention, A large amount of self-made solid waste source sulfur-aluminum-iron high-activity powder material is used as a cementitious material. In order to adjust the construction performance of the seat slurry, the present invention has shown through research that the addition of kaolin and limestone powder can cooperate with the solid waste source sulfur-aluminum-iron high-activity powder material to optimize the slurry plasticity, and the limestone powder can form hydrated carbon aluminate minerals when the cementitious material is hydrated, which can stabilize the crystal form of the main hydration product-calcium sulfoxide, so that the material strength continues to grow steadily, and no "shrinkage" will occur at any age. It plays an important role in the hydration system of solid waste source sulfur-aluminum-iron high-activity powder material.

[0041] Preferably, the quartz sand is a three-graded mixture of 20-40 mesh, 40-70 mesh, and 80-120 mesh in a mass ratio of 1.78:1.22:1. Reasonable gradation of aggregate can form a dense stack and improve the mechanical properties of the slurry.

[0042] Preferably, the water reducer is a dry powder polycarboxylic acid-based high-performance water reducer.

[0043] Preferably, the retarder is a mixture of sodium citrate and boric acid in a mass ratio of 1.2:1. The retarder of the present invention is selected to strongly retard the hydration of high-activity powder materials of the sulfur-aluminum-iron series from solid waste sources, while also slightly retarding the hydration of Portland cement, thereby meeting the construction requirements of the slurry.

[0044] Preferably, the cellulose ether may be hydroxypropyl methylcellulose ether, which is a type of non-ionic cellulose mixed ether. It is a semi-synthetic, inactive, viscoelastic polymer, and more preferably has a viscosity of 100,000 mPa·s.

[0045] Preferably, the redispersible latex powder is a polymer of vinyl acetate-ethylene, which can be dispersed when mixed with a slurry with water, a solid waste source sulfur-aluminum high-activity powder material, cement, fly ash, etc. as the base material. The basic particles (2um) therein will re-form a state equivalent to the original latex, and it has good redispersibility. More preferably, the viscosity of a 50% aqueous solution of the dispersible latex powder is 1.0-3.0 Pa·s.

[0046] The auxiliary agents of the present invention can all be purchased commercially, and the raw materials are easily available and have a wide range of sources.

[0047] The present invention also relates to a method for preparing the above-mentioned solid waste source high-activity powder base slurry, which specifically includes the following preparation steps:

[0048] 1) Weigh each raw material by mass;

[0049] 2) Add the weighed raw materials into the blender, mix well, and pack after passing the test.

[0050] The high-activity solid waste source powder slurry of the present invention can be tested or used on the construction site by adding water according to the mass ratio of slurry: water = 1:0.15-0.16 and stirring and mixing evenly.

[0051] The present invention has the following technical advantages:

[0052] 1. The high-activity powder of the solid waste source sulfur-aluminum-iron system of the present invention is a new, high-performance low-carbon material, which is derived from the resource utilization of industrial solid waste. The manufacture of the high-activity powder of the solid waste source sulfur-aluminum-iron system is based on the principle of complementary combination with bulk industrial solid waste for the design and calculation of the ingredient ratio. The production cost is greatly reduced compared with traditional sulfoaluminate cement, and it has good environmental and economic benefits. The calcination temperature in its production is low, the system energy consumption is low, and less limestone raw materials are used, and the process carbon emissions are significantly reduced, which is in line with the country's dual carbon strategy. It has many excellent properties such as early strength, fast setting, high durability, low hydration heat, and continuous improvement of later strength. It is used for the preparation of seat slurry to regulate the working properties of the seat slurry such as coagulation and curing time, plasticity, and micro-expansion, and while significantly improving the early strength of the seat slurry, it also continuously improves the later strength, which can achieve a two-level transition in the value of industrial solid waste.

[0053] 2. The present invention adopts active mineral fine powder (silica fume, fly ash, metakaolin) compounded with solid waste source sulfur-aluminum-iron series high-activity powder material to prepare seat slurry, which can improve the fineness and activity of the gel material components. Part of the active mineral fine powder can be hydrated to generate a large amount of gel phase, thereby reducing the small amount of defects in the microstructure of the hardened slurry caused by the rapid hardening of the solid waste source sulfur-aluminum-iron series high-activity powder, making the matrix structure denser and improving the seat slurry strength. At the same time, the hydration of dicalcium silicate in cement can release a certain amount of calcium hydroxide. These active mineral fine powders can produce secondary hydration reactions with calcium hydroxide to increase the number of hydration products, and achieve ideal density under suitable hydration and hardening conditions, thereby reducing its shrinkage and improving its durability such as anti-carbonization, anti-chloride ion penetration, and anti-freeze.

[0054] 3. In addition to exerting the volcanic ash effect and microcrystalline nucleus effect, metakaolin and limestone powder can also improve the construction performance of the slurry with the addition of high-activity powder of sulfur-aluminum-iron series from solid waste sources. The hydrated carbon aluminate minerals formed by limestone powder stabilize the hydration products of high-activity powder of sulfur-aluminum-iron series from solid waste sources, thereby avoiding the later shrinkage of the slurry strength.

[0055] 4. The setting time of the slurry of the present invention can be controlled, and it has the characteristics of high early strength and late strength, thixotropy, plasticity, micro-expansion, etc. It can be widely used in the fields of compartment division, sealing or cushioning at the joints of prefabricated components; mechanical equipment slurry installation construction and so on. DETAILED DESCRIPTION

[0056] In order to characterize the technical effect of the present invention, a slurry was prepared and its performance was tested. In the embodiment, the solid waste source sulfur-aluminum-iron high-activity powder material was prepared by washing fly ash, desulfurization gypsum, and aluminum ash in a mass ratio of 35:38:27, drying, grinding, passing through a 200 mesh sieve, and calcining at 1250°C for 30 minutes to prepare an intermediate, and the intermediate was mixed with gypsum in a mass ratio of 95:5 and ground to a specific surface area of 400m 2 / kg, Portland cement uses 42.5 grade Portland cement, fly ash uses Class I fly ash, and limestone powder is produced by further grinding stone chips and stone powder produced in the production of machine-made sand to make a particle size of no more than 10μm and a specific surface area of ≥500m 2 / kg, fine powder with a CaCO3 content of ≥99%, a dry powdered polycarboxylic acid-based high-performance water reducer, a retarder a mixture of sodium citrate and boric acid in a mass ratio of 1.2:1, hydroxypropyl methylcellulose ether, and a silicone defoamer. During the test, the slurry and water were mixed evenly in a mass ratio of 1:0.15.

[0057] Example 1

[0058] The seat slurry is prepared from the following raw materials in parts by weight: 80 parts of high-activity powder materials of the sulfur-aluminum-iron series from solid waste sources; 320 parts of Portland cement; 25 parts of silica fume; 40 parts of fly ash; 20 parts of metakaolin; 15 parts of limestone powder; 223 parts of 20-40 mesh quartz sand; 152 parts of 40-70 mesh quartz sand; 125 parts of 70-120 mesh quartz sand; 1.2 parts of water reducer; 1.2 parts of retarder; 0.3 parts of cellulose ether; 0.6 parts of redispersible latex powder; and 0.08 parts of defoaming agent.

[0059] After testing, the initial fluidity of the seat slurry is 185mm, the fluidity after 30 minutes is 160mm, the final setting time is 92 minutes, the compressive strength at 1 day is 37.9MPa, the compressive strength at 3 days is 55.9MPa, the compressive strength at 28 days is 75.2MPa, and the vertical expansion rate at 24 hours is 0.022%.

[0060] Example 2

[0061] The seat slurry is prepared from the following raw materials in parts by weight: 100 parts of high-activity powder materials of the sulfur-aluminum-iron series from solid waste sources; 300 parts of Portland cement; 30 parts of silica fume; 35 parts of fly ash; 20 parts of metakaolin; 15 parts of limestone powder; 223 parts of 20-40 mesh quartz sand; 152 parts of 40-70 mesh quartz sand; 125 parts of 70-120 mesh quartz sand; 1.2 parts of water reducer; 1.3 parts of retarder; 0.3 parts of cellulose ether; 0.6 parts of redispersible latex powder; and 0.08 parts of defoaming agent.

[0062] After testing, the initial fluidity of the seat slurry is 180mm, the fluidity of the seat slurry after 30 minutes is 160mm, the final setting time is 93min, the compressive strength at 1d is 39.6MPa, the compressive strength at 3d is 56.2MPa, the compressive strength at 28d is 74.1MPa, and the vertical expansion rate at 24h is 0.023%.

[0063] Comparative Example 1

[0064] The seat slurry is prepared from the following raw materials in parts by weight: 80 parts of sulphoaluminate cement; 320 parts of Portland cement; 25 parts of silica fume; 40 parts of fly ash; 20 parts of metakaolin; 15 parts of limestone powder; 223 parts of 20-40 mesh quartz sand; 152 parts of 40-70 mesh quartz sand; 125 parts of 70-120 mesh quartz sand; 1.2 parts of water reducer; 1.2 parts of retarder; 0.3 parts of cellulose ether; 0.6 parts of redispersible latex powder; and 0.08 parts of defoaming agent.

[0065] After testing, the initial fluidity of the seat slurry is 170mm, the fluidity of the seat slurry after 30 minutes is 130mm, the final setting time is 95min, the compressive strength at 1d is 36.1MPa, the compressive strength at 3d is 49.5MPa, the compressive strength at 28d is 66.3MPa, and the vertical expansion rate at 24h is 0.015%.

[0066] Comparative Example 2

[0067] The seat slurry is prepared from the following raw materials in parts by weight: 80 parts of high-activity powder materials of the sulfur-aluminum-iron series from solid waste sources; 320 parts of Portland cement; 25 parts of silica fume; 60 parts of fly ash; 15 parts of limestone powder; 223 parts of 20-40 mesh quartz sand; 152 parts of 40-70 mesh quartz sand; 125 parts of 70-120 mesh quartz sand; 1.2 parts of water reducer; 1.2 parts of retarder; 0.3 parts of cellulose ether; 0.6 parts of redispersible latex powder; and 0.08 parts of defoaming agent.

[0068] After testing, the initial fluidity of the seat slurry was 235mm, and the fluidity after 30 minutes was 205mm. The fluidity was too high, and flowing occurred during the construction process. The final setting time was 105min, the 1d compressive strength was 34.5MPa, the 3d compressive strength was 50.2MPa, the 28d compressive strength was 66.7MPa, and the 24h vertical expansion rate was 0.020%.

[0069] Comparative Example 3

[0070] The seat slurry is prepared from the following raw materials in parts by weight: 80 parts of high-activity powder materials of the sulfur-aluminum-iron series from solid waste sources; 320 parts of Portland cement; 25 parts of silica fume; 40 parts of fly ash; 35 parts of metakaolin; 223 parts of 20-40 mesh quartz sand; 152 parts of 40-70 mesh quartz sand; 125 parts of 70-120 mesh quartz sand; 1.2 parts of water reducer; 1.2 parts of retarder; 0.3 parts of cellulose ether; 0.6 parts of redispersible latex powder; and 0.08 parts of defoaming agent.

[0071] After testing, the initial fluidity of the seat slurry is 215mm, the fluidity of the seat slurry after 30 minutes is 140mm, the final setting time is 97min, the compressive strength at 1d is 36.3MPa, the compressive strength at 3d is 53.4MPa, the compressive strength at 28d is 62.6MPa, and the vertical expansion rate at 24h is 0.015%.

[0072] Comparative Example 4

[0073] The seat slurry is prepared from the following raw materials in parts by weight: 80 parts of solid waste source cementitious material according to the embodiment of our company's patent CN113800840A; 320 parts of Portland cement; 25 parts of silica fume; 40 parts of fly ash; 35 parts of limestone powder; 223 parts of 20-40 mesh quartz sand; 152 parts of 40-70 mesh quartz sand; 125 parts of 70-120 mesh quartz sand; 1.2 parts of water reducer; 1.2 parts of retarder; 0.3 parts of cellulose ether; 0.6 parts of redispersible latex powder; and 0.08 parts of defoaming agent.

[0074] After testing, the initial fluidity of the seat slurry is 155mm, the fluidity of the seat slurry after 30 minutes is 130mm, the final setting time is 180min, the compressive strength at 1d is 31.9MPa, the compressive strength at 3d is 36.7MPa, the compressive strength at 28d is 55.2MPa, and the vertical expansion rate at 24h is 0.012%.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-activity powder slurry from solid waste, characterized in that: It is composed of the following raw materials in parts by weight: 60-120 parts of high-activity powder materials of sulfur-aluminum-iron series from solid waste sources; 250-350 parts of Portland cement; 20-40 parts of silica fume; 30-50 parts fly ash; 15-25 parts of metakaolin; 10-20 parts of limestone powder; 450-550 parts of quartz sand; 0.8-1.6 parts of water reducer; Retarder 0.8-1.6 parts; 0.1-0.5 parts of cellulose ether; 0.4-0.8 parts of redispersible latex powder; Defoaming agent: 0.06-0.1 parts; The solid waste source sulfur-aluminum-iron series high-activity powder material is prepared by drying, grinding, screening and calcining washed fly ash, desulfurized gypsum and aluminum ash to prepare an intermediate, and then mixing the intermediate with gypsum and grinding it. The main component is Ca4Al6O 12 SO4 and Ca2SiO4, wherein the mass ratio of washed fly ash, desulfurized gypsum and aluminum ash is 32-38:35-40:25-30, the sieve mesh is 200 mesh, the calcination is kept at 1200-1300℃ for 20-40min, the mass ratio of intermediate to gypsum is 92-98:2-8, and the mixed powder is ground to a specific surface area of 400±10m 2 / kg.

2. The solid waste source high-activity powder slurry according to claim 1, characterized in that: It is composed of the following raw materials in parts by weight: 80 parts of high-activity powder materials of sulfur-aluminum-iron series from solid waste sources; 320 parts of Portland cement; 25 parts of silica fume; 40 parts of fly ash; 20 parts of metakaolin; 15 parts of limestone powder; 500 parts of quartz sand; 1.2 parts of water reducer; 1.2 parts of retarder; 0.3 parts of cellulose ether; 0.6 parts of redispersible latex powder; 0.08 parts of defoaming agent.

3. The solid waste source high-activity powder slurry according to claim 1, characterized in that: The silicate cement is 42.5 grade silicate cement.

4. The solid waste source high-activity powder slurry according to claim 1, characterized in that: The specific surface area of the silica fume is ≥2000m 2 / kg, activity index 120%.

5. The solid waste source high-activity powder slurry according to claim 1, characterized in that: The fly ash is Class I fly ash.

6. The solid waste source high-activity powder slurry according to claim 1, characterized in that: The limestone powder is obtained by further grinding the stone chips and stone powder produced during limestone crushing or machine-made sand production to obtain a particle size of no more than 10 μm and a specific surface area of ≥500 m 2 / kg, fine powder with CaCO3 content ≥99%.

7. The solid waste source high-activity powder slurry according to claim 1, characterized in that: The quartz sand is a three-graded mixture of 20-40 mesh, 40-70 mesh, and 80-120 mesh at a mass ratio of 1.78:1.22:

1.

8. The solid waste source high-activity powder slurry according to claim 1, characterized in that: The water reducer is a dry powder polycarboxylic acid high-performance water reducer; the retarder is a mixture of sodium citrate and boric acid in a mass ratio of 1.2:

1.

9. The method for preparing a high-activity powder slurry from solid waste sources according to any one of claims 1 to 8, characterized in that: The method comprises the following preparation steps: 1) Weigh each raw material by mass; 2) Add the weighed raw materials into the blender, mix well, and pack after passing the test.