Application of fine powder of secondary aluminum ash high temperature sintered slag and rapid hardening high strength sulphoaluminate cement-based grouting material containing the powder

Abstract

The invention provides an application of a ground powder of secondary aluminum ash high-temperature sintered slag and a fast-hardening high-strength sulphoaluminate cement-based grouting material containing the powder. The invention comprises mixing secondary aluminum ash with heavy sewage sludge and construction waste soil, drying the mixture and subjecting the mixture to high-temperature treatment to obtain a sintered slag, grinding the mixture to obtain a ground powder with an average particle size of 10-70 μm, and adding the ground powder to a sulphoaluminate cement (SAC) grouting material. The invention provides a method for preparing a grouting material by utilizing hazardous waste and harmful resources, and the grouting material has good mechanical properties, working performance and environmental friendliness, and has high commercial value and promotion value.

Description

Technical Field

[0001] The invention relates to the technical field of grouting material preparation, in particular to an application of secondary aluminum ash high-temperature sintered slag ground powder and a fast-hardening high-strength sulphoaluminate cement-based grouting material containing the powder. Background Art

[0002] Secondary aluminum ash is a secondary ash residue that is a hazardous waste produced by aluminum processing. Its safe utilization and disposal has become a key issue restricting the development of the aluminum industry and a hot topic of research at home and abroad. As the second largest metal after iron, aluminum is widely used in aviation, construction, automobile and other industries. Every ton of aluminum produced will produce 110kg of aluminum ash. Secondary aluminum ash comes from the ash residue produced by remelting primary aluminum ash or recycling aluminum from scrap aluminum. Secondary aluminum ash is mainly composed of alumina, aluminum, salt flux, iron, silicon, and magnesium oxides, and contains harmful substances such as aluminum nitride and fluoride. It has both resource and pollution properties. Kawashima Group of Japan and Tokai University jointly developed the technology of producing AD powder (steelmaking deoxidizer) using secondary aluminum ash and formulated the Japanese Industrial Standard "Aluminum Ash Slag Steel Accelerator" (JIS.G 2402). The Romanian National Institute for the Development of Cryogenic and Isotope Technology and the Turkish University of Science and Technology studied the use of secondary aluminum ash hydrolysis to produce hydrogen to recover hydrogen energy, and the Iran University of Science and Technology studied the use of aluminum ash to prepare adsorbents, catalysts and catalyst carriers. With the increasing requirements for environmental protection, the utilization and disposal of secondary aluminum ash has become an urgent problem to be solved in the aluminum processing industry, and the research and development of secondary aluminum ash utilization and disposal technology is very active. In the past five years, my country has received 79 patents for the utilization of aluminum ash, among which the main technical routes are the production of alumina (32%), calcium aluminate (23%), steelmaking additives (22%) and the production of building materials (5%). Co-disposal in cement kilns and the preparation of steelmaking deoxidizers / refining agents are typical examples of direct utilization of aluminum ash. Among them, the direct utilization technology of secondary aluminum ash and calcium oxide mixed with 50% to 65% of added calcium oxide to press steelmaking additives is represented by the Zhengzhou Research Institute of Aluminum Corporation of China, Zhejiang Yongji and Lanxi Boyuan. More technologies for the utilization of secondary aluminum ash use denitrification and desalination before reuse. Beijing University of Science and Technology, Aluminum Corporation of China Yunnan Wenshan and Zhejiang Yutao use hydrolysis to deamination and solid fluorine to produce flocculants and high-aluminum materials. Mingtai Aluminum desalts and deammines aluminum ash and then roasts it to convert it into active alumina. Sihui Huihuang Company and Lizhong Group melt calcium aluminate, which is a typical example of the pyrometallurgical utilization of aluminum ash. Chongqing Shunbo and others use secondary aluminum ash to directly make bricks. Foreign Ewais, Li and others make high-aluminum calcium aluminate cement by calcining bauxite at high temperature as a refractory material suitable for 2000℃ high temperature. Dai, Apelian and others added aluminum ash to silicate cement mortar and found that its flexural strength increased by 40% and its compressive strength increased by 15%. Zhang Yong in China found that adding an appropriate amount of magnesium oxide to secondary aluminum ash can sinter the secondary aluminum ash into magnesium-aluminum spinel refractory material.

[0003] Although there are many technologies for the utilization of secondary aluminum ash, most of them have certain limitations. The main problem is that the resource utilization of secondary aluminum ash has low utilization rate, high energy consumption and complex process. For example, the co-treatment of cement kilns, the production of water purifiers and refractory materials have small processing volumes. The production of alumina and calcium aluminate requires pretreatment, which is costly and brings about the problem of waste salt treatment. The preparation of steelmaking additives consumes a large amount of calcium oxide, produces a large amount of steel slag that is more difficult to handle, and fluorine pollution. It can be seen that economically feasible large-scale, full-component, and green utilization are the development direction of secondary aluminum ash utilization technology. Based on the above analysis, the utilization of secondary aluminum ash (Al 2 O 3 Mainly), heavy sewage sludge and construction waste (SiO 2 Based on the complementary characteristics of resource properties (mainly), the high-temperature sintering of secondary aluminum ash in coordination with heavy sludge and construction waste, and grinding the sintered slag after harmless treatment as a mineral admixture for use in high-strength cement-based materials is an important technical approach to achieve high-value utilization of secondary aluminum ash.

[0004] As we all know, the 21st century is a period of comprehensive development of geotechnical engineering construction such as underground space. Coastal cities have unique soft soil foundations. The soft soil gene has weak soil permeability, low shear strength, and easy thixotropy and rheology, which brings many problems to the construction of underground space. Rapid hardening and high-strength grouting material is one of the important materials for underground space engineering. Sulphoaluminate cement has excellent characteristics such as early strength, rapid hardening, high strength, low alkalinity and corrosion resistance. Wei Xuefei et al. added F10 melamine-based water reducer to sulphoaluminate cement and successfully prepared grouting materials that meet the requirements of broken rock reinforcement in the construction of underwater oil reservoirs. Wang Qian et al. applied special sulphoaluminate cement to the surrounding rock reinforcement of Qingdao Jiaozhou Bay submarine tunnel. Yan Guochao et al. added PU to SAC and found that the addition of PU significantly improved the working performance and early mechanical properties of SAC. At present, the use of sulphoaluminate grouting materials has not achieved the goal of reducing carbon emissions, and the emission of CO2 and energy consumption are still very high.

[0005] In summary, it is precisely because secondary aluminum ash synergizes with the rich silicon and aluminum substances in the high-temperature sintering slag of heavy soil that it can cooperate with the calcium, silicon and aluminum in sulphoaluminate cement to prepare green, low-carbon and high-strength modified sulphoaluminate cement-based grouting materials, thereby realizing a high-value resource utilization approach for secondary aluminum ash and synergistic solid waste. Summary of the invention

[0006] One of the technical problems to be solved by the present invention is to provide an application of high-temperature sintered slag of secondary aluminum ash ground into fine powder, so as to solve the problems of low resource utilization rate, high energy consumption and complex process of secondary aluminum ash in the current prior art.

[0007] In order to solve the above problems, the present invention provides an application of fine powder of high-temperature sintered slag of secondary aluminum ash, which includes drying and high-temperature treating the slag obtained by mixing secondary aluminum ash with heavy construction waste to obtain sintered slag, grinding to obtain fine powder, and adding the fine powder to SAC grouting material.

[0008] As a preferred solution, the construction waste soil includes heavy sewage sludge and construction waste soil, and the mass ratio of the heavy sewage sludge, construction waste soil and the secondary aluminum ash is 52:30:18.

[0009] As a preferred solution, the high temperature treatment is to add the mixture of the secondary aluminum ash and construction waste to a high temperature of 1000-1200°C for sintering.

[0010] As a preferred solution, the particle size of the ground powder is 10-70 μm.

[0011] The invention discloses an application of a secondary aluminum ash high temperature sintered slag ground powder. The ground powder is prepared by mixing the secondary aluminum ash with heavy construction waste soil, sintering at high temperature and then grinding the mixture to obtain the ground powder. The ground powder is applied to SAC (sulfoaluminate cement) grouting material to replace SAC in equal amounts to prepare a fast-hardening high-strength grouting material. The secondary aluminum ash is mixed with other heavy construction waste and then sintered. The secondary aluminum ash and heavy construction waste are mixed and sintered through a harmless reaction. The sintered material is ground into fine powder to stimulate its activity. The ground powder contains silicon-aluminum substances provided by the construction waste and the active alumina phase provided by the secondary aluminum ash to form silicon-aluminum substances with certain activity at high temperature. The main mineral composition of fast-hardening sulphoaluminate cement is anhydrous calcium sulphoaluminate and dicalcium silicate. Therefore, adding the ground powder to the SAC grouting material can provide active silicon-aluminum minerals for the system, thereby achieving a good synergistic effect of the two, and realizing the safe consolidation of harmful substances such as aluminum nitride, fluoride and calcium fluoride in the secondary aluminum ash ground powder, thereby reducing its harm to the environment, and finally preparing a green, low-carbon, fast-hardening, high-strength grouting material with good mechanical properties and strong volume stability.

[0012] Another technical problem to be solved by the present invention is to provide a fast-hardening and high-strength sulphoaluminate cement-based grouting material containing the powder, so as to solve the problems that conventional grouting materials have average mechanical properties and volume stability and poor environmental friendliness.

[0013] In order to solve the above problems, the present invention provides a fast-hardening and high-strength sulphoaluminate cement-based grouting material containing the powder, wherein the cement-based grouting material is composed of sulphoaluminate cement, the above-mentioned ground powder and water.

[0014] As a preferred solution, the ratio of the total mass of the sulphoaluminate cement and the above-mentioned ground powder to the mass of the water is 1:0.45.

[0015] As a preferred solution, the ratio of the total mass of the sulphoaluminate cement to the powder is (19:1) to (4:1).

[0016] As a preferred solution, the particle size of the SAC grouting material rapid hardening sulphoaluminate cement is 2-50 μm.

[0017] The invention discloses a fast-hardening high-strength sulphoaluminate cement-based grouting material containing the powder. The powder is prepared by mixing secondary aluminum ash and heavy construction waste, drying them at high temperature and grinding them, applying the powder to the grouting material, and preparing high-strength grouting material with the ground powder, fast-hardening high-strength sulphoaluminate cement and water, thereby utilizing hazardous waste. The prepared grouting material has good mechanical properties, volume stability and environmental friendliness, has high promotion value and commercial value, and ultimately provides technical theory and effective support for realizing high-value utilization of secondary aluminum ash. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the raw material particle size distribution diagram;

[0019] Figure 2 It is the X-ray diffraction analysis diagram of the raw material;

[0020] Figure 3 This is the stability test result of SAC grouting material with different AP dosages;

[0021] Figure 4 The flow chart of the stone rate test of fast-hardening high-strength SAC grouting materials with different AP content, where (a) is the forming diagram, (b) is the diagram of placing it in a beaker and letting it stand, and (c) is the diagram of the stone rate test after 2 hours;

[0022] Figure 5 The flow chart of the expansion rate test of fast-hardening high-strength SAC grouting materials with different AP content, where (a) is the forming diagram, (b) is the immersion curing diagram, and (c) is the expansion rate measurement diagram;

[0023] Figure 6 Schematic diagram of setting time and fluidity of fast-hardening high-strength SAC grouting materials with different AP content;

[0024] Figure 7 Schematic diagram of the compressive and flexural strength of fast-hardening high-strength SAC grouting materials with different AP content under water curing, where (a) is the tensile strength and (b) is the flexural strength.

[0025] Figure 8 Schematic diagram of water resistance of fast-hardening high-strength SAC grouting materials with different AP dosages, where (a) is a compressive water resistance test diagram, and (b) is a flexural water resistance test diagram;

[0026] Fig. 9Schematic diagram of stone rate of fast-hardening high-strength SAC grouting materials with different AP content;

[0027] Fig.10 The expansion rate of fast-hardening high-strength SAC grouting materials with different AP content varies with age, where (a) is the 1d expansion rate, (b) is the 3d-15d expansion rate, and (c) is the long-term expansion rate;

[0028] Fig.11 This is the heavy metal concentration diagram in fast-hardening high-strength SAC grouting materials with different AP dosages;

[0029] Fig.12 XRD phase analysis spectra of fast-hardening high-strength SAC grouting materials with different AP content at different ages, among which (a) is the analysis spectrum at 3d, (b) is the analysis spectrum at 28d, and (c) is the analysis spectrum at 60d;

[0030] Fig.13 Thermogravimetric analysis diagrams of fast-hardening and high-strength SAC grouting materials with different AP content at different ages, among which (a) is the analysis diagram at 3 days, (b) is the analysis diagram at 28 days, and (c) is the analysis diagram at 60 days;

[0031] Fig.14 IR analysis diagrams of fast-hardening and high-strength SAC grouting materials with different AP dosages at different ages, among which (a) is the analysis diagram at 3 days, (b) is the analysis diagram at 28 days, and (c) is the analysis diagram at 60 days. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The AP in the present invention as described below refers to the ground powder of secondary aluminum ash high temperature sintered slag, and SAC refers to rapid hardening sulphoaluminate cement.

[0034] The present invention provides an application of secondary aluminum ash high-temperature sintered slag ground into fine powder, the application comprising drying and high-temperature treating the slag obtained by mixing secondary aluminum ash with heavy construction waste to obtain slag, grinding the slag to obtain fine powder, and adding the fine powder into SAC grouting material.

[0035] As a preferred solution, the construction waste soil includes heavy sewage sludge and construction waste soil, and the mass ratio of the heavy sewage sludge, construction waste soil and the secondary aluminum ash is 52:30:18.

[0036] As a preferred solution, the high temperature treatment is to add the mixture of the secondary aluminum ash and construction waste to a high temperature of 1000-1200°C for sintering.

[0037] As a preferred solution, the particle size of the ground powder is 10-70 μm.

[0038] The present invention also provides a fast-hardening and high-strength sulphoaluminate cement-based grouting material containing the powder. The cement-based grouting material consists of sulphoaluminate cement, the powder and water.

[0039] As a preferred solution, the ratio of the total mass of the SAC containing calcium sulfoaluminate, calcium sulfate, tricalcium silicate and aluminum oxide and the powder to the mass of the water used is 1:0.45.

[0040] As a preferred solution, the ratio of the total mass of the SAC containing calcium sulfoaluminate, calcium sulfate, tricalcium silicate and aluminum oxide to the powder is (19:1)-(4:1).

[0041] As a preferred solution, the particle size of SAC in the SAC grouting material is 2-50 μm.

[0042] The above scheme of the present invention is explained and illustrated below in combination with specific raw material types, addition amounts and specific implementation data:

[0043] Raw materials and mix ratio

[0044] The experiment used fast-hardening sulphoaluminate cement (SAC) with a strength grade of 62.5 produced by Jiangxi Yinshan New Materials Co., Ltd. The secondary aluminum ash high-temperature sintered slag powder (abbreviated as ground powder, AP) came from Yuyuan Ninghai Environmental Protection Technology Co., Ltd. and construction waste. The construction waste included heavy sewage sludge and construction sludge, and the mass ratio of the heavy sewage sludge, construction sludge and the secondary aluminum ash was 52:30:18. Figure 1 and Figure 2 The particle size distribution and XRD phase analysis diagram of SAC and AP are shown in Figure 2. Figure 1 It can be seen that the main particle sizes of SAC cement are distributed in 2~3μm and 20~50μm, and the main particle sizes of AP are distributed in 10~20μm and 50~70μm; Figure 2 It can be seen that SAC is mainly composed of calcium sulfoaluminate, calcium sulfate, tricalcium silicate, and alumina, and AP is mainly composed of alumina, metallic aluminum, magnesium, and nickel oxide, and contains harmful substances such as aluminum nitride and fluoride.

[0045] Table 1 shows the mix proportions of fast-hardening high-strength SAC grouting materials containing different amounts of AP, where the water-binder ratio is 0.45, L0 is the benchmark mix proportion without AP, and the percentages of AP replacing SAC of equal mass in other series of mixes are 5%, 10%, 15%, 20% and 30% respectively.

[0046] Table 1 Proportion of secondary aluminum ash high temperature sintered slag ground powder sulphoaluminate cement slurry / g

[0047] serial number water SAC SAC Ground powder Water-cement ratio L0 546.8 1215.2 0 0.45 L5 3554.39 7503.71 394.93 0.45 L10 3554.39 7108.78 789.86 0.45 L15 3554.39 6713.84 1184.80 0.45 L20 3554.39 6318.91 1579.73 0.45 L30 3554.39 5529.05 2369.59 0.45

[0048] Trial plan

[0049] Experimental study on the effect of different AP dosage on the working performance of fast-hardening high-strength SAC grouting material

[0050] (1) Experimental study on the effect of different AP dosages on the setting time and fluidity of fast-hardening high-strength SAC grouting materials

[0051] The corresponding fast-hardening high-strength grouting material was mixed according to the mix proportion in Table 1, and its initial setting time was tested according to the "Test Method for Water Consistency, Setting Time and Stability of Cement Standard Consistency" (GB / T1346-2011). The fluidity of the fast-hardening high-strength SAC grouting material with different AP dosages was tested according to the cement paste fluidity test method in the "Test Method for Homogeneity of Concrete Admixtures" (GB / T8077-2000).

[0052] (2) Experimental study on the effect of different AP dosages on the stability of fast-hardening high-strength SAC grouting slurry

[0053] According to the mix ratio in Table 1, 50 ml of the corresponding grouting material is mixed for each group and poured into a 200 ml beaker. After standing for 2 hours, the volume of clear water precipitated from the slurry is measured. The ratio of the volume of precipitated water to the total volume of the slurry is used to characterize the stability of the grouting material slurry. Some test samples are shown in Figure 3 As shown in the figure, it can be seen that the rapid hardening sulphoaluminate cement grouting material has good stability after adding AP, and no clear water precipitates on the surface.

[0054] Experimental study on the influence of different AP dosage on the mechanical properties of fast-hardening high-strength SAC grouting materials

[0055] According to Table 1, 6 groups of 40mm×40mm×160mm specimens were prepared for each series of mix proportions. The molds were removed after 2 hours of molding. Four groups of specimens were placed in water after demolding to simulate the underground geotechnical working environment of the grouting material, and the compressive and flexural strengths of the specimens were measured at 1d, 3d, 28d, and 60d. Two groups of specimens were placed in a standard curing room with a temperature of 20±2℃ and a relative humidity greater than 95% after demolding to measure the flexural and compressive strengths of the specimens at 3d and 60d. The compressive and flexural softening coefficients of the AP-added rapid hardening high-strength SAC grouting material at different ages were calculated according to the public notice (1), and its water resistance was analyzed.

[0056] K=f / F(1)

[0057] Where:

[0058] K—Compression / flexural softening coefficient

[0059] f—compressive strength under water saturation, MPa

[0060] F—is the compressive strength of the material under standard curing conditions, MPa.

[0061] 1.2.3 Experiment on the influence of different AP dosage on the volume stability of rapid hardening high strength SAC grouting material

[0062] (1) Experimental study on the effect of different AP dosages on the stone rate of fast-hardening high-strength SAC grouting material

[0063] The stone rate refers to the ratio of the initial volume of the slurry to the volume of the stone after solidification. According to the mix ratio in Table 1, 50 ml of the corresponding grouting material is mixed for each group, injected into a 200 ml beaker, and the volume of the stone body after hardening is measured after standing for 3 hours. The stone rate is calculated by the ratio of the initial volume of the grouting material to the volume of the stone body after early hardening. See the test steps for details. Figure 4 shown.

[0064] (2) Experimental study on the effect of different AP dosages on the expansion rate of fast-hardening high-strength SAC grouting materials

[0065] According to Table 1, one group of 40mm×40mm×160mm specimens were prepared for each series of mix proportions. The molds were removed after 2 hours. A straight line was drawn on the surface of the specimen with a marker to determine the measurement position of the vernier caliper. The initial length L of the specimen was measured with a vernier caliper with a minimum scale of 0.1mm. 1 . Then immediately put it in water for curing, and measure the time length Lt at different times. Measure it every 2 hours within 1 day, twice a day within 2 to 3 days, once a day within 4 to 7 days, and so on. The expansion rate test is based on the expansion rate calculation formula (2) in the "Expansion Rate Test Method for Expansion Cement" JC / T313-2009 to calculate the expansion rate Ex of each group of specimens at different ages. The calculation result has an accuracy of 0.01%. For the specific test process, see Figure 5 The standard mold size is 25mm×25mm×250mm and the effective length is 250mm. This experiment uses a 40mm×40mm×160mm mold, so the effective length is 160mm.

[0066]

[0067] Where:

[0068] Ex — Expansion rate of the specimen at a certain age, in percentage (%)

[0069] L 1 — is the initial length reading of the test piece, in mm;

[0070] L t — Length readings of the test piece at different times, in mm;

[0071] 160 — The effective length of the specimen is 160 mm.

[0072] Experimental study on the effect of different AP dosage on the leaching of harmful substances in SAC grouting material

[0073] According to the mix ratio of L0, L5, L15 and L30 in Table 1, 4 groups of AP rapid hardening sulphoaluminate cement mortar were mixed, and a three-joint mold specimen with a size of 40mm×40mm×160mm was formed for each group. The demoulding specimens were cured in a room with a temperature of 20±2℃ and a humidity of 95%±5% for 90 days. The cured specimens were crushed and ground, sieved with a square hole sieve, and particles with a particle size of 0.125mm~0.25mm were collected as the test samples. The test solution was prepared using a magnetic stirrer (CJB-S-10D) and a circulating water multi-purpose vacuum pump (SHZ-D(Ⅲ)), and then the concentration of heavy metals such as Ni, Cr, Zn, and Cu in the sample was tested using an atomic absorption spectrophotometer (TAS-990). For specific operations, refer to GB / T30810-2014 "Determination of leached heavy metals in cement mortar".

[0074] Microscopic mechanism test on the effect of different AP dosage on the properties of rapid hardening and high strength SAC grouting material

[0075] Microscopic test samples were taken from crushed specimens with a size of 40mm×40mm×160mm that had been immersed in water for 3d, 28d, and 60d of curing. After the samples were taken, they were all immersed in anhydrous ethanol for 48h. A part of them was taken out and ground into powder with a mortar and passed through a 0.02mm aperture sieve, and then subjected to XRD, TG and IR microscopic phase analysis respectively; another part of the anhydrous ethanol immersed samples were taken out and SEM microscopic morphology and structure analysis was carried out.

[0076] Results and Discussion

[0077] Effect of different AP dosage on the working performance of fast-hardening high-strength SAC grouting material

[0078] Figure 6 The results show the effect of different AP dosages on the setting time and fluidity of fast-hardening high-strength SAC grouting materials. Figure 6Analysis shows that the setting time and fluidity of the fast-hardening high-strength SAC grouting material are significantly prolonged after the addition of AP. When the AP content is 30%, the setting time increases most significantly compared with the grouting material without AP, with an increase of up to 66%. When the AP content is 15%, the setting time increases most slowly compared with the grouting material without AP, with an increase of 40%. When the AP content is 5% and 10%, the fluidity of the fast-hardening high-strength SAC grouting material increases linearly. When the AP content is equal to 10%, the grouting material completely covers the surface of the fluidity tester. Therefore, when the AP content is greater than 10%, the fluidity of the fast-hardening high-strength SAC grouting material does not change significantly with the increase of the AP content.

[0079] Effect of different AP dosage on the working performance of fast-hardening high-strength SAC grouting material

[0080] Figure 7 The results show the influence of different AP dosages on the mechanical properties of fast-hardening high-strength SAC grouting materials under water curing conditions. Figure 7 It can be seen that the compressive strength of fast-hardening high-strength SAC grouting materials with different AP dosages increases with the increase of curing age, and the compressive strength increases the most in the range of 3 days to 28 days. The compressive strength of early fast-hardening high-strength SAC grouting materials increases first and then decreases with the increase of AP dosage, while the long-term compressive strength of fast-hardening high-strength SAC grouting materials decreases with the increase of AP dosage. The flexural strength of grouting materials with an AP dosage of 5% to 10% increases with the increase of curing age, and the flexural strength of grouting materials with an AP dosage of 15% to 30% decreases first and then increases with the increase of curing age. Figure 7 (a) It can also be seen that the compressive strength of the rapid hardening high-strength SAC grouting material with an AP content of 15% at the early stage of 1 day and 3 days is significantly higher than that of the grouting materials with other content. When the age is 28 days and above, the compressive strength of the rapid hardening high-strength SAC grouting materials with different AP content is lower than that of the grouting material without AP, and the decrease is more obvious with the increase of AP content. Figure 7 (b) It can be seen that at the same age, the flexural strength of the rapid hardening high-strength SAC grouting material increases first and then decreases with the increase of AP content. Among them, the improvement of the flexural strength of the SAC grouting liquid is the largest when the AP content is 5%. This is mainly due to the Al in the early secondary aluminum ash fine powder. 2 O 3 The aluminum phase accelerated the formation of the hydration product AFt and enhanced the early flexural strength of the specimen. Figure 8 It can be seen that when the AP content ranges from 5% to 10%, the compressive strength and flexural strength of the AP-added rapid-hardening high-strength SAC grouting material are not much different from the strength of the benchmark SAC grouting liquid without AP.

[0081] Figure 8This is the water resistance analysis result of AP-added rapid hardening high-strength SAC grouting material after immersion in water for 3 days and 60 days. Figure 8 (a) It can be seen that the softening coefficient of the 3-day water immersion compressive strength of the fast-hardening high-strength SAC grouting material after adding AP first decreases and then increases with the increase of AP content. When the AP content is 15%, the softening coefficient of the 3-day water immersion compressive strength of the fast-hardening high-strength SAC grouting material is the highest. Figure 8 (a) It can also be seen that the 60-day water immersion compressive softening coefficient of the rapid hardening high-strength SAC grouting material after adding AP is significantly lower than that of the control specimen without AP. When the AP content ranges from 5% to 10%, the 60-day water immersion compressive strength softening coefficient is not much different from that of the sample without AP. Figure 8 (b) It can be seen that the flexural softening coefficient of the rapid hardening high-strength SAC grouting material is significantly greater than 1, especially the 60-day immersion flexural softening coefficient of the rapid hardening high-strength SAC grouting material with different AP additions is significantly higher than that of the benchmark specimen without AP, which indicates that the flexural and water resistance of the rapid hardening high-strength SAC grouting material is significantly improved after adding AP. Comprehensive analysis Figure 8 It can be seen that when the AP dosage range is 5%~10%, the compression, flexural and water resistance of the AP fast-hardening high-strength SAC grouting material are most suitable.

[0082] Effect of different AP dosage on volume stability of rapid hardening and high strength SAC grouting material

[0083] Effect of different AP dosage on stone rate of rapid hardening high strength SAC grouting material

[0084] Fig. 9 The results of the stone rate change of fast-hardening high-strength SAC grouting materials with different AP dosages are shown in the figure. It can be seen from the figure that compared with the SAC grouting materials without AP, the addition of AP significantly increases the stone rate of fast-hardening high-strength SAC grouting materials, and with the increase of AP dosage, the stone rate of fast-hardening high-strength SAP grouting materials shows a trend of first increasing and then decreasing. Among them, the stone rate of fast-hardening high-strength SAC grouting materials with an AP dosage of 15% is the highest, and the stone rate of grouting materials with an AP dosage of 0% is increased by 40%. This shows to a certain extent that AP can significantly reduce the early hardening shrinkage deformation value of fast-hardening high-strength SAC grouting materials, especially when the AP dosage is 15%, the shrinkage deformation value is reduced the most, which greatly improves the early reinforcement effect of SAC grouting fluid.

[0085] Effect of different AP dosage on expansion rate of rapid hardening and high strength SAC grouting material

[0086] Fig.10The following are the results of the expansion rate of fast-hardening high-strength SAC grouting materials with different AP dosages over time. It can be seen that the volume expansion rate of the fast-hardening SAC grouting material with an AP dosage of 15% is the highest, and the volume expansion rate has been showing a gradual increase from 3d to 15d. The fast-hardening high-strength SAC grouting materials with other AP dosages all show volume shrinkage after 3 days of age. With the increase of age, the expansion rate of the grouting material with an AP dosage of 15% is the highest. Fig.10 (a) It can be seen that the expansion rate of the grouting material with an AP content of 15% is much greater than that of other grouting materials. Fig.10 (a) It is not possible to obtain the effect of different AP dosages on the expansion rate of SAC grouting material. Fig.10 (b) It can be seen that, except for the grouting material with an AP content of 15%, which continues to expand, the expansion rates of the grouting materials with other AP content all shrink. Ignoring the grouting material with an AP content of 10%, the grouting materials with an AP content of 5% to 15% still expand, and the expansion rates of the grouting materials with an AP content of 20% and 30% are already lower than those without AP. Fig.10 (c) It can be seen that with the passage of age, the expansion rate of the fast-hardening and high-strength SAC grouting materials with different AP content decreases, and the expansion rate of the grouting materials remains basically unchanged after 40 days of age.

[0087] The data results show that the higher the AP content, the slower the hydration of the grouting material, the slower the amount of hydration products such as AFt and aluminum glue increases, and the slower the peak of the expansion rate appears. From the long-term expansion rate change chart, it can be seen that hydration products such as AFt and aluminum glue will appear in the later stage when the gypsum content decreases and SO 4 2- When the ion concentration is insufficient, it transforms into monosulfide calcium sulfoaluminate hydrate and shrinks. The higher the Aft content in the hydration product, the more obvious the shrinkage.

[0088] Analysis of harmful substances leaching from fast-hardening and high-strength SAC grouting materials with different AP dosages

[0089] Table 2 shows the heavy metal leaching concentration test results of fast-hardening high-strength SAC grouting materials with different AP dosages. It can be seen from the values ​​in the table that Ni, Cr, Zn, and Cu elements were not detected in the specimens with AP dosages of 0% and 5%; the Zn element leaching concentration is the highest, but it still meets the requirements of the "Technical Specifications for Co-disposal of Solid Wastes in Cement Kilns" GB30760-2014 for the limit value of heavy metal elements in cement clinker, and the Cu element leaching concentration is much lower than the standard limit. Therefore, the ground powder studied in this paper can be safely mixed with cement for application in actual projects.

[0090] Table 2 Heavy metal leaching concentrations in SAC grouting materials with different AP dosages (mg / L)

[0091]

[0092] ND: Not Detected

[0093] Fig.11 is the concentration of heavy metals in rapid-hardening SAC grouting materials with different AP dosages, Fig.11 The information in the figure shows that the ground powder itself has a certain amount of heavy metal content. Compared with the heavy metal content of the ground powder itself, the concentration of heavy metals leached from the fast-hardening SAC grouting material after adding 5%~15% AP is greatly reduced, which plays a good consolidation role. The concentration of heavy metals leached from the fast-hardening SAC grouting material increases significantly after adding 30% AP, but it is still far below the prescribed heavy metal concentration limit. Fig.11 It can also be seen that the consolidation rates of the four heavy metals Ni, Cr, Zn and Cu of the fast-hardening SAC grouting material with AP content of 0% and 5% are 100%, and the consolidation rates of the four heavy metals Ni, Cr, Zn and Cu of the fast-hardening SAC grouting material with AP content of 15% are 36.3%, 20.5%, 40.7% and 27.1% respectively. This shows that the fast-hardening SAC grouting material has a good consolidation effect on various heavy metals in AP, especially for the three heavy metals Ni, Zn and Cu.

[0094] Microscopic mechanism analysis of the effects of different AP dosages on the properties of rapid hardening and high strength SAC grouting materials

[0095] Fig.12 The XRD phase analysis results of fast-hardening high-strength SAC grouting materials with different AP content at different ages. Fig.12 It can be seen that after hydration, the grouting material mainly contains calcium aluminate phase, CSH gel phase, ASH gel phase, and hydrated calcium iron sulfate phase. With the increase of age, the peak value of the main hydration products has no obvious change. From the XRD phase analysis results of hydration products at different ages, no harmful substances such as aluminum nitride and calcium fluoride were found, which shows that the fast-hardening SAC grouting material has a good consolidation efficiency for materials such as F and Ca contained in aluminum nitride and calcium fluoride in AP. Fig.12 (a) It can be seen that the ettringite peaks numbered L5, L15 and L30 are higher than L0, which further confirms that the addition of AP can improve the stone rate and expansion rate of the rapid hardening and high-strength SAC grouting material. Fig.12 (b) and 12 (c) show that when the AP content is 30%, the peak strength of the ettringite phase is stronger than that of the specimens with other content, while the strength of other phases has no obvious change. This is consistent with the fact that the compressive strength of the specimens with 30% content is significantly lower than that of the specimens with other content at the age of 28d and 60d.

[0096] Fig.13The TG-DTG curves of fast-hardening high-strength SAC grouting materials with different AP content at 3d, 28d, and 60d. Fig.13 It can be seen that when the sample is heated to 900℃, there are three mass loss peaks, namely, the Aft dehydration endothermic peak from room temperature to 100℃, the AH 3 Dehydration endothermic peak, and CaCO at 710℃~730℃ 3 Decomposition endothermic peak. Fig.13 As can be seen from (a), the area L0 enclosed by the curve at 20℃~100℃, 220℃~270℃, and 710℃~730℃ is the largest, and gradually decreases with the increase of the doping amount, that is, AH in L0 3 Gel and Aft, CaCO 3 The larger the number, the more AP replaces the cement, resulting in the formation of hydration product AH 3 Gel, Aft and Ca(OH) 2 Decrease, from Fig.13 It can be seen from (b) and (c) that the area L30 enclosed by the curve at 20℃~100℃, 220℃~270℃, and 710℃~730℃ is the largest, and that is, AH in L30 3 Gel and Aft, CaCO 3 The large number is consistent with the results of XRD analysis, which further proves that AP will reduce the later strength of the grouting material.

[0097] Fig.14 The IR analysis results of fast-hardening high-strength SAC grouting materials with different AP content at 3d, 28d, and 60d. Fig.14 It can be seen that the SO of fast-hardening high-strength SAC grouting materials with different AP content 4 2- OH - The peak values ​​of the antisymmetric stretching vibrations of CO, C=O all show an increasing trend with the increase of age, indicating that with the development of the hydration process, the Aft, AH in the grouting material 3 The content of substances such as Fig.14 As can be seen from (a) and (b), the SO of L15 4 2- OH - The content of is higher than other contents. This result shows that the Aft content in L15 is the highest, which further verifies that its mechanical properties are better than those of other grouting materials. Fig.14 (c) shows that the OH content of the grouting material specimen added with 30% secondary aluminum ash fine powder is - High content, SO 4 2-The content is second only to the control group without adding secondary aluminum ash fine powder. This feature shows that the Aft content in the grouting material with this dosage is the highest, which is consistent with the XRD analysis results. 4 2- The contents are higher than those of other specimens added with AP. 4 2- When the ion concentration is insufficient, Aft and aluminum gel are easily transformed into monosulfide calcium sulfoaluminate hydrate. Therefore, the mechanical properties of the grouting material will shrink and the expansion rate will decrease in the later stage.

[0098] Through the above embodiments, the following technical advantages and conclusions of the present invention are obtained:

[0099] (1) The setting time and fluidity of the fast-hardening high-strength SAC grouting material were significantly prolonged after adding different amounts of AP. When the AP content was 15%, the setting time of the fast-hardening SAC grouting material was the shortest. The early compressive strength of the fast-hardening high-strength SAC grouting material increased first and then decreased with the increase of AP content, and the long-term compressive strength decreased with the increase of AP content. When the AP content was 5-10%, the compressive strength of the fast-hardening high-strength SAC grouting material was not much different from the control sample without AP addition, especially the corresponding flexural strength of the immersion curing was better than that of the SAC grouting material without AP addition.

[0100] (2) Different AP dosages increased the stone rate of the fast-hardening high-strength SAC grouting slurry. With the increase of AP dosage, the stone rate showed a trend of first increasing and then decreasing. The stone rate was the highest when the AP dosage was 15%. Except for the grouting material with an AP dosage of 15%, the expansion rate of other fast-hardening high-strength SAC grouting materials with different AP dosages decreased after 3 days. The fast-hardening high-strength grouting material with an AP dosage of 15% had the highest expansion rate at different ages, which was consistent with the results of the stone rate.

[0101] (3) The rapid-hardening SAC grouting material added with AP has a consolidation effect on heavy metals such as Ni, Cr, Zn and Cu. The consolidation ratios of the rapid-hardening SAC grouting material added with 15% AP for the four heavy metals are 36.3%, 20.5%, 40.7% and 27.1%, respectively. Its leaching behavior and leaching concentration indicators meet the relevant requirements of the national standard GB30760-2014.

[0102] (4) The main hydration products of fast-hardening high-strength SAC grouting material are Aft, ASH gel and CSH gel, and their contents increase with the increase of AP content. 3 Gel and Aft, CaCO 3The largest amount; at the early age, the Aft content in the fast-hardening high-strength grouting material with an AP content of 15% is the largest, while at the old age, the Aft content in the fast-hardening high-strength SAC grouting material with an AP content of 30% is the largest. This to a certain extent explains the obvious strength shrinkage of the fast-hardening high-strength SAC grouting materials with different AP content in the later stage.

[0103] At the same time, it is also further proved that the application of the ground powder of high-temperature sintered slag of secondary aluminum ash provided by the present invention and the fast-hardening and high-strength sulphoaluminate cement-based grouting material containing the powder can effectively solve the problems of low recycling rate of secondary aluminum ash, general mechanical properties and volume stability of conventional grouting materials, and poor environmental friendliness.

[0104] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. Application of secondary aluminum ash high temperature sintering slag powder, Features: The application includes drying and high-temperature treating the slag obtained by mixing secondary aluminum ash with heavy sewage sludge and construction waste to obtain sintered slag, grinding to obtain fine powder, and adding the fine powder to SAC grouting material; The mass ratio of the heavy sewage sludge, construction waste and the secondary aluminum ash is 52:30:18; the high temperature treatment is to add the mixture of the secondary aluminum ash, the heavy sewage sludge and the construction waste to a high temperature of 1000-1200°C for sintering; the particle size of the ground powder is 10-70μm.

2. A fast-hardening, high-strength sulphoaluminate cement-based grouting material, Features: The cement-based grouting material comprises sulphoaluminate cement, the ground powder according to claim 1 and water.

3. The fast-hardening high-strength sulphoaluminate cement-based grouting material according to claim 2, Features: The ratio of the total mass of sulphoaluminate cement and the ground powder to the mass of water is 1:0.

45.

4. The fast-hardening high-strength sulphoaluminate cement-based grouting material according to claim 2, Features: The ratio of sulphoaluminate cement to the ground powder is (19:1)-(4:1).

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