Tailings cementitious material composite activator proportioning decision method

Abstract

The application discloses a tailing cementitious material composite activator proportioning decision method, and belongs to the technical field of energy-saving and environment-friendly and green mining filling. The implementation steps are as follows: according to the particle size gradation of the mineral processing tailings, the filling slurry concentration range is determined, and the slurry concentration of the cemented filling body strength test is determined; the proportioning range of the alkali solid waste and salt solid waste activator is designed, and the tailing cemented filling body strength test is carried out; the filling body weighted strength and the cementitious material cost performance are calculated; the relationship function between the cementitious material cost performance and the alkali and salt proportioning is fitted respectively by using the polynomial regression analysis, the optimal proportioning of the composite activator alkali and salt is obtained, and the tailing green filling cementitious material activator proportioning decision is carried out. By using the method, the tailing filling cementitious material optimization design is carried out, the test workload is small, the difficulty of solving the activator optimal proportioning is low, the green filling cementitious material with high cost performance and strong adaptability can be prepared, and thus the tailing filling mining technology is promoted and applied in the filling mine.

Description

Technical Field

[0001] This invention relates to the field of green backfilling mining technology for the resource utilization of various solid wastes, and in particular to a decision-making method for the proportion of composite activators in green and environmentally friendly tailings backfilling cementitious materials. Background Technology

[0002] To achieve safe, environmentally friendly, and green mining of mineral resources and to realize clean production in mining enterprises, tailings backfilling mining is the primary choice. However, tailings backfilling mining has a complex recovery process, low production capacity, and high mining costs. The cost of backfill cementitious materials accounts for a major part of the overall cost of backfilling mining. Therefore, the development and industrial application of low-cost new backfill cementitious materials is the only way to improve the economic and environmental benefits of tailings backfilling mining.

[0003] Over the past decade or so, the development of new green and environmentally friendly backfilling cementitious materials and their preparation methods using various metallurgical industrial solid wastes such as slag, steel slag, and desulfurized gypsum has been a key research topic in tailings backfilling mining technology. Currently, many invention patents and academic papers on new backfilling cementitious materials have been published.

[0004] CN104529197A (A method for preparing a novel composite cementitious material) discloses the proportions and method for preparing a composite activator using desulfurized gypsum, sodium silicate, and calcium oxide. CN109320176A (A novel coal slime cementitious material for mine backfilling) discloses the formulation and preparation method for a backfill material using fine coal powder, coal slime, cement, and special additives. CN109336433A (A method for producing a novel cementitious material using industrial waste slag) proposes the proportions and preparation method for producing a novel cementitious material using industrial waste slag as raw material. CN110330243A (A novel cementitious material for clinker-free tailings backfilling) proposes a formulation for preparing a novel cementitious material using slag powder, fly ash, steel slag powder, desulfurized gypsum, sodium sulfate, red mud, and triethanolamine. CN111187010A (A novel high-performance, low-cost composite cementitious material without clinker) discloses a formula for a novel composite cementitious material composed of quicklime, desulfurization ash, modified materials, and composite admixtures. CN111217543B (A multi-component synergistic tailings backfill cementitious material and its preparation method) discloses a formula for preparing tailings backfill cementitious materials using fine tailings, phosphogypsum, stearic acid, liquid sodium silicate, polymer, sulfate activator, alkaline solid activator, water-reducing agent, slag, steel slag, and desulfurization gypsum. CN116282984A (Green cementitious material, novel roadbed material and its preparation method) discloses a formula for a green cementitious material using desulfurization ash, steel slag powder, slag powder, and construction waste powder. CN116496009A (Ultra-fine tailings backfill cementitious material and its backfilling material mainly composed of copper slag and fly ash) proposes a formula for preparing ultra-fine tailings backfill cementitious material using copper slag powder, fly ash, cement clinker, high-strength gypsum powder and alkaline activator.

[0005] In summary, the early disclosed inventions of novel backfilling cementitious materials mainly provided a formulation and preparation method for the material. Due to the regional limitations of solid waste utilization and the varying requirements for cementitious materials in different backfilling mining methods, the aforementioned patented technologies for novel backfilling cementitious materials are limited to specific mines, environments, regions, and mining methods. Given the complex and variable composition of industrial solid waste, simply disclosing the formulation of novel backfilling cementitious materials is insufficient to achieve the desired results; furthermore, the disclosed novel backfilling cementitious materials do not provide analysis or evaluation of their economic and environmental benefits for solid waste utilization.

[0006] To address the limitations of earlier inventions, recent patented technologies in the research and development of novel filling cementitious materials involve methods for optimizing the proportions of novel cementitious materials. Chinese patents CN110655376B (A method for co-preparing green cementitious materials with steel slag and a multi-objective optimization method), CN107311582B (A method for determining the proportions of low-cost, early-strength cementitious materials), CN107117888B (A method for determining the proportions of mixed aggregate filling slurry for mining), CN113387671B (A method for optimizing the proportions of water-resistant and stable green filling materials for large-scale mines), CN103723967B (A method for determining the proportions of filling cementitious materials for mining), CN111191387B (An optimization method for phosphogypsum-based cementitious materials to improve the filling roof contact rate), and CN111508566B (A method for preparing low-cost filling cementitious materials by composite activation of multiple solid wastes) all disclose optimization methods for developing novel cementitious materials using industrial solid waste. This approach uses the cost of cementitious materials as the optimization objective and the safe production of cementitious materials in backfill mines as a constraint. It establishes and solves an optimization model for the proportions of novel backfill cementitious materials, thereby obtaining an optimized formulation. Compared to earlier patents on novel cementitious materials, the key technology of this recent patent lies in making formulation decisions by establishing and solving an optimization model for novel backfill cementitious materials, rather than simply disclosing a single formulation. Therefore, this recent patent technology can adapt to the complex and variable characteristics of solid waste and the requirements of different mining methods on cementitious material properties. Clearly, the recently disclosed patent technology has significant advantages.

[0007] Although recent inventions have made breakthroughs in the development of backfill cementitious materials, the following major problems still exist: The experimental workload for new cementitious materials is large, the development cycle is long, solving the optimization model is difficult, and it cannot quickly adapt to the requirements of developing cementitious materials for different mining methods and varying solid waste characteristics. For example, staged subsequent backfilling mining methods have high requirements for later-stage strength and low requirements for early-stage strength; while downward layered backfilling mining methods have high requirements for both early-stage and later-stage strength. Furthermore, using backfilling mining cost as the optimization objective in the optimization model fails to consider the impact of the cost-effectiveness of new cementitious materials on the cementitious material proportioning decisions.

[0008] By analyzing early and recently disclosed patents on novel cementitious materials, the applicant believes that the core technology for developing green and environmentally friendly filling cementitious materials using industrial solid waste is the widespread use of alkali activators, salt activators, or alkali-salt composite activators to activate potentially active volcanic ash materials (such as blast furnace slag and fly ash), causing them to undergo a hydrohardening reaction, thereby preparing novel filling cementitious materials. Extensive research and practice in developing novel filling cementitious materials have shown that using composite activation to develop green filling cementitious materials achieves the best results. In summary, the key technology for developing green filling cementitious materials using industrial solid waste lies in exploring a rapid, simple, and reliable method for determining the ratio of alkali and salt in a composite activator. This method not only enables the development of novel filling cementitious materials from various complex and variable solid wastes but also allows for the simple and rapid acquisition of optimized formulations for preparing novel cementitious materials from both alkali and salt solid wastes. Summary of the Invention

[0009] To address the shortcomings of existing patents in the background art, the patent technology disclosed in this invention features the following: Considering the strength requirements of different mining methods for backfill bodies and the potential variability of the physicochemical components of industrial solid waste, different weights are applied to the strength of backfill bodies at different ages to calculate the weighted strength of the cemented backfill body. Then, based on the utilization cost of industrial solid waste (utilization cost of solid waste raw materials and processing cost), the cost of green backfill cementitious materials is calculated. The cost-effectiveness of the cementitious material is defined as the ratio of the weighted strength of the cemented backfill body to the cost of the cementitious material. Based on the strength test of the cemented backfill body, regression analysis is used to fit the relationship function between the cost-effectiveness of the new cementitious material and the ratio of alkali and salt activators. By solving for the extreme values ​​of the relationship function, the optimal ratio of the composite activator for the new backfill cementitious material is determined, thereby overcoming the deficiency in the background art that does not consider the cost-effectiveness of the new green cementitious material. By optimizing the ratio of composite activators based on the cost-effectiveness of filling cementitious materials, we can utilize complex and varied solid waste resources to develop new filling cementitious materials with the lowest cost and stronger mechanical properties, thereby promoting the large-scale and high-value application of various industrial solid wastes in filling mining.

[0010] This application discloses a method for proportioning a composite activator for tailings cementitious materials, the implementation steps of which are as follows:

[0011] 1) Perform particle size distribution analysis on tailings to obtain the content of -200 mesh fine sand and -400 mesh ultrafine tailings; determine the slurry concentration range for tailings filling slurry fluidity and stability tests;

[0012] 2). Based on step 1), fix the slurry ash-sand ratio, and conduct fluidity and stability tests within the slurry concentration range to obtain the test results of the consistency and bleeding rate of the tailings filling slurry;

[0013] 3). Based on step 2), and taking into account that the fluidity and stability of the filling slurry meet the requirements for gravity-flow transportation of the slurry pipeline, determine the concentration of the filling slurry for conducting the tailings cemented filling strength test;

[0014] 4). Following step 3), solid wastes such as converter steel slag, refining slag, magnesium slag, or carbide slag are used to replace cement clinker as alkali activators, while solid wastes such as desulfurization gypsum from power plants and steel mills, and phosphogypsum or fluorogypsum from chemical enterprises are used as salt activators. A composite activator is prepared using alkali-salt solid wastes to activate potentially active pozzolanic substances such as blast furnace slag / or fly ash, thereby preparing a green filling cementitious material. Based on R&D experience, the alkali and salt ratio range of the composite activator for the green filling cementitious material is determined.

[0015] 5). Based on steps 3) and 4), conduct strength tests on the cemented tailings backfill of the green backfill material, and obtain the test results of the 3-day and 7-day strength of the cemented tailings backfill, respectively;

[0016] 6). Based on step 5), take the weighted values ​​of the 3-day and 7-day strength data of the cemented tailings backfill body and calculate the weighted strength of the cemented backfill body; based on the utilization cost of solid waste raw materials and the processing and production cost of green cementitious materials, calculate the ratio of the strength of the cemented tailings backfill body to the cost of cementitious materials, thereby obtaining the cost-effectiveness of green cementitious materials.

[0017] 7). Based on steps 5) and 6), calculate the average cost-effectiveness of green cementitious materials with alkali and salt as composite activators;

[0018] 8). Based on step 7), using the salt-to-alkali ratio corresponding to the alkali and salt with the highest average cost-effectiveness of green cementitious materials, multinomial regression analysis is used to fit the relationship function between the cost-effectiveness of green cementitious materials and the salt-to-alkali ratio.

[0019] 9). Based on step 8), differentiate the function relating the cost-effectiveness of the green cementitious material to the salt and alkali ratios, and set it to zero to obtain the extreme values ​​of the function, thus obtaining the alkali-salt ratio of the composite activator for the filling cementitious material:

[0020] 10) Calculate the cost-effectiveness of green cementitious materials based on the two sets of activator ratios, compare the cost-effectiveness of the two sets of cementitious materials, and finally select the green cementitious material ratio with the activator ratio that has the highest cost-effectiveness.

[0021] Preferably, in step 1), the tailings particle size distribution analysis specifically includes: analyzing the content of -200 mesh fine sand (α%) and -400 mesh ultrafine tailings (β%) in the tailings; and determining the slurry concentration range for the tailings filling slurry working characteristic test. m 1%~ m4%; when α < 70% and β < 40%, the slurry concentration range is 66% to 72%; when α < 75% and β < 50%, the slurry concentration range is 64% to 70%.

[0022] Preferably, in step 2), the ash-sand ratio of the tailings filling slurry is selected to be 1:4.

[0023] Preferably, in step 3), the fluidity and stability requirements for the gravity-flow transportation of tailings backfill slurry through pipeline are determined, and the consistency of the tailings backfill slurry is determined. L i ≥13cm Water secretion rate W i ≤15% .

[0024] Preferably, in step 6), the formula for calculating the weighted strength of the cemented infill is:

[0025] R i q = q 3d × R ij 3d + q 7d × R ij 7d

[0026] in, R i q The weighted strength of the cemented infill. q 3d The weighted values ​​represent the 3-day strength of the cemented infill. q 7d The weighted value for the 7-day strength of the cemented infill is... R ij 3d The 3-day strength of the cemented infill. R ij 7d The 7-day strength of the cemented infill. i This indicates the test protocol for cemented fillers. j This indicates the 3-day and 7-day strength of the cemented infill.

[0027] Preferably, in step 6), in the subsequent backfilling mining method, q 3d =0.3、q 7d =0.7;

[0028] In the upward filling mining method, q 3d =0.4、q 7d =0.6;

[0029] In the downfill mining method, q 3d =0.5、q 7d =0.5.

[0030] Preferably, in step 9),

[0031] By differentiating the relationship function between the cost-effectiveness of green filling cementitious materials and the salt and alkali ratios, and setting it to 0, the extreme values ​​of the relationship function are obtained. The solution formula is as follows:

[0032] d C H T / db=d f 1 ( b 1. b 2. b 3. b 4) / db=0 (1)

[0033] d C K T / da=d f 2 ( a 1. a 2. a 3. a 4) / da=0 (2)

[0034] Solving equation (1) yields the proportion of salt activator in the green cementitious material composite activator. b ;

[0035] Solving equation (2) yields the ratio of alkali activator in the green cementitious material composite activator. a .

[0036] Compared with the patented technologies disclosed in the background technology of filling cementitious materials, this invention patent not only requires less experimental work, shorter research and development cycle, and less difficulty in solving the activator formulation, but also enables rapid decision-making on the ratio of composite activators based on limited experimental work. Furthermore, it makes decisions on the ratio of composite activators based on the cost-effectiveness of filling cementitious materials, and can utilize a variety of complex and variable solid wastes to develop green new filling cementitious materials. It can also obtain new filling cementitious materials with low cost and high performance, providing green filling cementitious materials for different filling mining methods, thereby promoting the construction of green mines. Attached Figure Description

[0037] Figure 1 This is a curve showing the relationship between the strength of the cementitious filling material and the salt ratio when the alkali activator is 12% in an embodiment of the present invention.

[0038] Figure 2This is a curve showing the relationship between the cost-effectiveness of the cementitious material and the salt ratio when the alkali activator is 12% in an embodiment of the present invention.

[0039] Figure 3 This is a curve showing the relationship between the strength of the cementitious filling material and the alkali ratio when the salt activator is 10% in an embodiment of the present invention.

[0040] Figure 4 This is a curve showing the relationship between the cost-effectiveness of the cementitious material and the alkali ratio when the salt activator is 10% in an embodiment of the present invention. Detailed Implementation

[0041] To more clearly illustrate the decision-making method for the ratio of composite activator for green and environmentally friendly tailings cementitious materials disclosed in this invention, as well as the key technologies and implementation steps involved, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation examples.

[0042] The specific implementation plan includes the following six steps:

[0043] Step 1: Tailings particle size analysis and determination of slurry concentration range

[0044] (1) A tailings sample was taken from a lead-zinc mine in Inner Mongolia, and the particle size distribution of the tailings was analyzed. The results are shown in Table 1. According to Table 1, the content of -200 mesh (-75 μm) fine tailings α=56.48% and the content of -400 mesh (-38 μm) ultrafine tailings β=26.87% in the tailings.

[0045] (2) Based on the content of fine and ultrafine tailings in the tailings, and with the help of research and development experience, the slurry concentration range for the tailings filling slurry fluidity and stability test was determined to be 62%~68%.

[0046] Table 1 Test results of total tailings particle size distribution

[0047]

[0048] Step 2: Determine the strength test concentration based on the slurry working characteristic test.

[0049] (1) Based on the tailings slurry concentration range of 62%~68% determined in step 1, a ash-sand ratio of 1:4 (the ash-sand ratio does not affect the optimization of the cementitious material ratio) was adopted to carry out the fluidity (consistency) and stability (bleeding rate) test of the full tailings filling slurry. The test results are shown in Table 2.

[0050] (2) The tailings filling slurry meets the requirements of fluidity and stability for gravity-flow transportation in the pipeline. L≥13cm , W≤ 15%Based on the test results of the working characteristics of the tailings slurry in Table 2, the tailings slurry concentration for the tailings cemented backfill strength test was determined to be 66%.

[0051] Table 2 Test results of working characteristics of tailings backfill slurry

[0052]

[0053] Step 3: Strength test of tailings backfill with cementitious material

[0054] (1) Based on the tailings slurry concentration determined in step 2 m =66% and ash-sand ratio 1:4. Converter steel slag was used as an alkali activator and desulfurized gypsum as a salt activator. Experiments were conducted to develop a green cementitious material composite activator. Based on experience in cementitious material R&D, the alkali activator formulation was designed. a i Salt activator ratio b j The range is a i =10%~16%、b j =4%~10% ( i, j =1, 2, 3, 4) 。

[0055] (2) Based on the sand-cement ratio of the tailings slurry and the alkali-salt ratio range of the cementitious material, a 2% incremental ratio was adopted. The strength test of the cemented tailings filling body was carried out according to the cement mortar strength test method B / T17671-1999 to obtain the strength R of the cemented tailings filling body. ij 3d R ij 7d (See Tables 3 and 4).

[0056] Table 3. Test results of tailings backfill strength determined by the proportion of composite activator for novel backfill cementitious materials.

[0057]

[0058]

[0059] Table 4. Test results of tailings backfill strength determined by the proportion of composite activator for novel backfill cementitious materials.

[0060]

[0061]

[0062] Step 4: Fit the relationship function between the cost-effectiveness of the cementitious material and the ratio of salt and activator.

[0063] (1) According to Table 3 and Table 4, the 3-day and 7-day strength of the filling body R ij 3d , R ij 7d ( i= 1~4 、j= (1-4) Based on the strength requirements of the backfill body in the subsequent backfill mining method, the 3-day and 7-day strengths of the backfill body are weighted respectively. R q 3d , R q 7d Calculate the weighted strength of the filling material. R ij q = R ij 3d R q 3d + R ij 7d R q 7d (See Tables 3 and 4).

[0064] (2) Calculate the cost of cementitious materials based on the alkali and salt activator solid waste materials and processing costs utilized in green cementitious materials. C ij T Based on the weighted strength of the filling material R ij q Calculate the cost-effectiveness of cementitious materials: C ij X = R ij q / C ij T ( i =1, 2, 3, 4 、j= 1, 2, 3, 4 (see Tables 3 and 4);

[0065] (3) Based on the cost-effectiveness of cementitious materials in Tables 3 and 4, the average cost-effectiveness of cementitious materials was calculated for each ratio of alkali and salt activator, and the average cost-effectiveness of alkali activator was obtained respectively. C i X ( i =1, 2, 3, 4 (see Table 3) and the mean value of salt activator C j X (j =1, 2, 3, 4 (see Table 4);

[0066] (4) According to Tables 3 and 4, the average cost-effectiveness of alkali and salt activated cementitious materials C i T ( i =1, 2, 3, 4), C j X ， ( j =1, 2, 3, 4), respectively determine the alkali activator ratio that maximizes the average cost-effectiveness of the cementitious material: C H T =Max C i T = C 2 T =25.7 kPa / yuan (see Table 5), and the salt activator ratio with the highest average cost-effectiveness: C K T =Max C j T = C 4 T =24.5 kPa / yuan (see Table 6).

[0067] Table 5. Ratio of alkali activator to salt activator corresponding to the highest average cost-effectiveness of novel cementitious materials.

[0068]

[0069] Table 6 shows the ratio of salt-activated to alkali-activated agents corresponding to the highest average cost-effectiveness of novel cementitious materials.

[0070]

[0071] (5) Based on the alkali ratio with the highest average cost-effectiveness of cementitious materials in Table 5 a 2=12% and the corresponding salt activator ratio b j ( j =1, 2, 3, 4), the relationship curves between the 3-day and 7-day strength of the cementitious material filling and the salt activator ratio are shown in the figure. Figure 1 The relationship between the cost-effectiveness of cementitious materials and the ratio of salt activator is shown in the curve. Figure 2 .according to Figure 2 Fitting function between the cost-effectiveness of cementitious materials with a medium alkali ratio of 12% and the salt activator ratio:

[0072] C HX=-0.0491 b 2 + 1.1872 b + 20.053 R² = 0.8761 (1)

[0073] (6) Based on the salt ratio with the highest average cost-effectiveness of cementitious materials in Table 6 a 2=10% and the corresponding alkali ratio a i ( i =1, 2, 3, 4), the relationship curves between the 3-day and 7-day strength of the cementitious material filling and the salt activator ratio are shown in the figure. Figure 3 The relationship between the cost-effectiveness of cementitious materials and the ratio of salt activators is shown in the curve. Figure 4 .according to Figure 4 The fitting function between the maximum mean cost-effectiveness of cementitious materials and the salt activator ratio, with an alkali activator content of 12%, is as follows:

[0074] C K X = -0.3125 a 2 + 7.545 a - 19.36 R² = 0.8488 (2)

[0075] Step 5: Determine the alkali-salt ratio of the composite activated cementitious material with the highest cost-effectiveness.

[0076] Differentiate the relational functions of equations (1) and (2) respectively and set them to 0:

[0077] d C H X / d b =d(-0.0491 b 2 + 1.1872 b + 20.053) / db=0 (3)

[0078] The ratio of the composite activator to the alkali-salt activator was determined as follows: a =12% b =12.09%;

[0079] d C K X / d a =d(-0.3125 a 2 + 7.545 a - 19.36) / d a =0 (4)

[0080] The ratio of alkali to salt activator in the composite activator was determined as follows: a=12.07%, b =10%.

[0081] Step 6. Final decision on the alkali-salt ratio of the cementitious material composite activator.

[0082] Using the alkali and salt ratio method of the composite activator for filling cementitious materials disclosed in this application, two sets of alkali-salt activator ratios were obtained as follows: (1) a =12% ​​and b =12.09%; (2) a =12.07% and b =10%. Substituting the two sets of activator ratios into equations (1) and (2) respectively, the cost-effectiveness of the green cementitious material is calculated as follows:

[0083] C H X =-0.0491×12.092 + 1.1872×12.09+20.053=27.2kPa / yuan (5)

[0084] C K X =-0.3125×12.07 2 + 7.545×12.07 - 19.36=26.2 kPa / yuan (6)

[0085] Comparing the cost-effectiveness of the two groups of activator ratios for cementitious materials, it is evident that the activator ratio in group (1) is greater than that in group (2). The final determined composite activator ratio for the cementitious material is: a =12% ​​and b =12.09%.

[0086] Based on the optimization decision-making method of this patent, an optimized formula for a novel backfill cementitious material was obtained for a lead-zinc mine in Inner Mongolia. Utilizing steel slag, mineral slag, and desulfurized gypsum from local metallurgical industrial solid waste, the novel backfill cementitious material was prepared. The strength of the tailings cemented backfill material was significantly improved compared to the traditional optimized formula (17% alkali activator, 3% salt activator), and the cost of the cementitious material was reduced to (111.6 / 124.8) = 89.4%. The novel cementitious material obtained in this application has already been applied in a large iron mine in Hebei Province. This large iron mine requires approximately 900,000 tons of the novel tailings backfill cementitious material annually. Based on this calculation, the annual economic benefit of applying this novel cementitious material at full production capacity could reach 30 yuan / t × 900,000 tons / year = 27 million yuan / year.

[0087] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. For example, refining slag (white slag) and reduced magnesium slag from steel enterprises can be used instead of converter steel slag, and phosphogypsum and fluorogypsum can be used instead of desulfurization gypsum. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining the proportion of composite activator for tailings cementitious materials, characterized in that, The steps are as follows: 1) Particle size distribution analysis was performed on the tailings to obtain the content of -200 mesh fine sand and -400 mesh ultrafine tailings; thereby determining the filling slurry concentration range for the slurry fluidity and stability test. 2). Based on step 1), with a fixed ash-sand ratio, conduct fluidity and stability tests within the slurry concentration range to obtain the test results of the consistency and bleeding rate of the tailings filling slurry; 3). Based on step 2), determine the filling slurry concentration for the tailings cemented backfill strength test to ensure that the fluidity and stability of the tailings slurry meet the requirements of gravity-flow transportation in the pipeline; 4). Based on step 3), select alkaline solid waste such as converter steel slag, refining slag or magnesium slag as alkali activator, and desulfurized gypsum, phosphogypsum or fluorogypsum sulfidation solid waste as salt activator. Use experience to design the alkali and salt ratio range of the tailings green cementitious material composite activator. 5). Based on steps 3) and 4), an alkali-salt composite activator is used to compositely activate the potential activity of blast furnace slag and / or fly ash pozzolanic materials, and a tailings cemented backfill strength test is carried out to obtain 3-day and 7-day strength test data of tailings cemented backfill. 6). Based on step 5), the weighted values ​​of the 3-day and 7-day strengths of the tailings cemented backfill are taken respectively, and the weighted strength of the tailings cemented backfill is calculated; based on the utilization cost of solid waste raw materials and the processing cost of green cementitious materials, the ratio of the backfill strength to the cost of cementitious materials is calculated to obtain the cost-effectiveness of green cementitious materials. 7). Based on steps 5) and 6), calculate the average cost-effectiveness of the green cementitious material with the correct ratio of alkali and salt in the composite activator. 8). Based on step 7), using the salt-to-alkali ratio corresponding to the alkali and salt activator with the highest average cost-effectiveness of green cementitious materials, multinomial regression analysis is used to fit the relationship function between the cost-effectiveness of green cementitious materials and the salt-to-alkali ratio. 9). Based on step 8), differentiate the function relating the cost-effectiveness of green cementitious materials to the salt and alkali ratios, and set it to zero to obtain the extreme values. This yields the alkali-salt ratio of the composite activator for green cementitious materials: 10) Calculate the cost-effectiveness of green cementitious materials based on the ratio of the two sets of composite activators. By comparing the cost-effectiveness of the two sets of green cementitious materials, the activator of the green cementitious material with the highest cost-effectiveness is taken as the optimal ratio.

2. The tailings cementitious material composite activator ratio decision method according to claim 1, characterized in that, In step 1), the tailings particle size distribution analysis specifically includes: Based on the content α% of -200 mesh fine sand and β% of -400 mesh ultrafine tailings in the tailings, the concentration range for the tailings backfill slurry working characteristic test was determined. m 1%~ m 4%; when α < 70% and β < 40%, the slurry concentration range is 66% to 72%; when α < 75% and β < 50%, the slurry concentration range is 64% to 70%.

3. The tailings cementitious material composite activator ratio decision method according to claim 1, characterized in that, In step 2), the ash-sand ratio of the tailings filling slurry is selected to be 1:

4.

4. The tailings cementitious material composite activator ratio decision method according to claim 1, characterized in that, In step 3), the consistency of the tailings backfill slurry is determined based on the fluidity and stability requirements of the gravity-flow transport of the tailings backfill slurry through the pipeline. L i ≥13cm Water secretion rate W i ≤15% .

5. The tailings cementitious material composite activator ratio decision method according to claim 1, characterized in that, In step 6), the formula for calculating the weighted strength of the tailings cemented backfill is: R i q = q 3d × R ij 3d + q 7d × R ij 7d in, R i q Representing the i Weighted strength of cemented filler in each test scheme q 3d The weight representing the 3-day strength of the cemented tailings backfill. q 7d The weight representing the 7-day strength of the cemented tailings backfill. R ij 3d To represent the 3-day strength value of the cemented tailings backfill, R ij 7d This represents the 7-day strength value of the cemented tailings backfill.

6. The tailings cementitious material composite activator ratio decision method according to claim 5, characterized in that, In step 6), for the subsequent backfilling mining method, q 3d =0.3、 q 7d =0.7; For the upward filling mining method q 3d =0.4、 q 7d =0.6; For the downfill mining method q 3d =0.5、 q 7d =0.

5.

7. The tailings cementitious material composite activator ratio decision method according to claim 1, characterized in that, In step 9), the derivative of the relationship function between the cost-effectiveness of the green cementitious material and the salt and alkali ratio is calculated and set to 0. The extreme value of the relationship function is then obtained, and the calculation formula is as follows: d C H T / db=d f 1( b 1、 b 2、 b 3、 b 4) / db=0 (1) d C K T / da=d f 2( a 1、 a 2、 a 3、 a 4) / from=0 (2) Solving equation (1) yields the salt activator ratio in the green cementitious material composite activator. b ; Solving equation (2) yields the ratio of alkali activator in the green cementitious material composite activator. a .

Images