Underground mine filling material prepared from metallurgical solid waste and preparation method thereof

Abstract

The invention provides an underground mine filling material prepared from metallurgical solid waste and a preparation method thereof, and the filling material comprises Portland slag cement, fly ash, whole tailings, water and a flocculant; the preparation method comprises the following steps: diluting the whole tailings with water by using a thickener until the concentration is 10-12%, adding the flocculant according to the mixing amount of 10-15g / t, accelerating the precipitation of the whole tailings, adding the whole tailings, the Portland slag cement, the fly ash and the water into a stirrer, and preparing the filling material in a high-speed flexible activation stirring manner. According to the method, the total tailings in the metallurgical solid waste are selected as the filling aggregate, the coal ash is selected as the cementing material, the cement consumption is reduced, the optimal flocculant type, mixing amount and dilution concentration of the total tailings are determined through a plurality of tests, the sedimentation rate of the total tailings is increased, and the solid content of overflow water is reduced; the filling material has higher strength and long-term stability through an optimized ratio, so that the safety and the overall efficiency of underground mine mining operation are remarkably enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground mine mining, and relates to an underground mine filling material prepared by utilizing metallurgical solid waste and a preparation method thereof. Background Art

[0002] In the production process of the metallurgical industry, a large amount of solid waste is inevitably generated, such as whole tailings and metallurgical slag. Among them, whole tailings are fine-grained materials remaining after the ore is sorted through the mineral processing process. They have small particle size, huge output, and often contain metal elements and other mineral components. At present, the main disposal method for this type of metallurgical solid waste is open-air storage or landfill; however, this type of disposal method in the existing technology has significant problems: on the one hand, large-scale solid waste storage will occupy valuable land resources; on the other hand, the fine particles in the solid waste and the harmful components that may be contained are easily leached by rainfall, dispersed by wind, etc., causing continuous pollution to the surrounding soil, water and atmospheric environment, posing an environmental pollution risk.

[0003] While some studies have shown that metallurgical solid waste (such as tailings and slag) has the potential to be used as mine filling aggregate due to its physical and chemical properties, existing technologies still face technical bottlenecks and challenges in efficiently, stably, and on a large scale in mine filling projects, particularly in ensuring fill performance (such as strength, fluidity, and long-term stability) and effectively controlling environmental risks. Therefore, there is an urgent need to develop new technologies or methods that can effectively solve the problem of metallurgical solid waste disposal and efficiently utilize it as a resource for mine filling. Summary of the Invention

[0004] The purpose of the present invention is to address the problems existing in the prior art and provide an underground mine filling material prepared using metallurgical solid waste and a preparation method thereof, which solves the problems of limited sources and high costs of traditional filling materials, as well as the problem of insufficient strength and stability of materials used for mine filling.

[0005] To this end, the present invention adopts the following technical solutions:

[0006] An underground mine filling material prepared from metallurgical solid waste comprises the following components in parts by weight:

[0007] 58-122 parts of slag Portland cement, 15-30 parts of fly ash, 1296-1377 parts of whole tailings, 509-510 parts of water, 0.013-0.014 parts of flocculant;

[0008] The slurry concentration of the filling material is 74%; the mass ratio of slag silicate cement to fly ash is 4:1.

[0009] Whole tailings from metallurgical solid waste are selected as filling aggregate to ensure that the chemical composition of the whole tailings meets the environmental protection requirements of underground filling and contains no or very little toxic and harmful substances; slag silicate cement and fly ash are selected as cementitious materials to reduce filling costs and improve the strength of the filling body.

[0010] Specifically, the particle gradation of the whole tailings is: particle size 0-20 μm: 30.83-32.66%, particle size 21-74 μm: 23.2-25.03%, particle size 75-500 μm: 43.47-45.61%.

[0011] The flocculant used is polyacrylamide flocculant, and the chemical formula of the flocculant is (CH2CHCONH2)n; the flocculant dosage is 10-15g / t.

[0012] The specific gravity of the whole tailings is 2.96 and the loose bulk density is 1.477t / m 3 , dense bulk density is 1.933t / m 3 The loose void ratio of the whole tailings dry material is 50.9% and the dense void ratio is 35.8%.

[0013] A method for preparing underground mine filling materials using metallurgical solid waste comprises the following steps:

[0014] S1. Use a thickener to dilute the whole tailings with water to a concentration of 10-12%;

[0015] S2. Add flocculant at a dosage of 10-15g / t to accelerate the sedimentation of the tailings;

[0016] S3. Add the whole tailings, slag silicate cement, fly ash and water into a mixer, and stir for 3 to 5 minutes at a time through a high-speed flexible activated stirring method to obtain a filling material.

[0017] The beneficial effects of the present invention are:

[0018] 1. The present invention not only converts metallurgical solid waste tailings into effective filling materials and replaces traditional natural sand and gravel aggregates, but also significantly reduces the cost of raw materials for filling materials and the investment in natural aggregate mining and processing. It not only solves the problem of storage and disposal of metallurgical solid waste, but also promotes the recycling of solid waste.

[0019] 2. The present invention optimizes the ratio of filling materials to provide them with higher strength and long-term stability, effectively improving the support effect on the goaf, thereby significantly enhancing the safety and overall efficiency of underground mining operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a particle size analysis table of the whole tailings of the present invention;

[0021] Figure 2 This is a graph showing the change of the solid-liquid separation interface height with time for different flocculants in the present invention;

[0022] Figure 3 This is a graph showing the change in sedimentation height over time for different full tailings slurry concentrations according to the present invention;

[0023] Figure 4 The strength test curve of cement and fly ash ratio of the present invention;

[0024] Figure 5 The graph is a strength test graph of filling materials with different concentrations and different lime-sand ratios according to the present invention;

[0025] Figure 6 This is a graph showing the slurry flow resistance of filler materials with different concentrations according to the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described below in conjunction with the accompanying drawings and implementation methods.

[0027] An underground mine filling material prepared from metallurgical solid waste and a preparation method thereof, comprising the following components in parts by weight:

[0028] 58-122 parts of slag silicate cement, 15-30 parts of fly ash, 1296-1377 parts of whole tailings, 509-510 parts of water, and 0.013-0.014 parts of flocculant.

[0029] Specifically, the particle gradation of the whole tailings is: particle size 0-20 μm: 30.83-32.66%, particle size 21-74 μm: 23.2-25.03%, particle size 75-500 μm: 43.47-45.61%.

[0030] The specific gravity of the whole tailings was determined by the pycnometer method, and the bulk density, porosity and particle size distribution of the whole tailings were determined by standard methods. The specific gravity of the whole tailings was finally selected to be 2.96 and the loose bulk density was 1.477t / m 3 , dense bulk density is 1.933t / m 3 The loose void ratio of the whole tailings dry material is 50.9% and the dense void ratio is 35.8%.

[0031] The experiment for determining the specific gravity of whole tailings is as follows.

[0032] The specific gravity of the whole tailings is measured using the pycnometer method. The specific experimental steps are as follows:

[0033] 1. Select a standard pycnometer (25 ml), clean it with detergent, dry it, and weigh it with a balance with a sensitivity of one ten-thousandth of a gram. The mass of the pycnometer is m1;

[0034] 2. Take the dried material sample and put it into the bottle. The amount of material sample filled is about 1 / 3 of the volume. Weigh the mass m2 of the pycnometer and the material sample;

[0035] 3. Pour distilled water into the bottle to 2 / 3 of its volume, boil it in a hot water bath, remove bubbles attached to the sample, let it cool, then fill the bottle mouth with distilled water, plug the bottle, and let water overflow from the capillary on the plug to indicate that the bottle is full of water. Wipe off the water outside the bottle and weigh the mass m3 of the specific gravity bottle and natural water;

[0036] 4. Pour out the water and material sample from the bottle, rinse it and fill it with distilled water, and weigh the mass of the bottle and water m4.

[0037] The formula for calculating specific gravity is as follows:

[0038]

[0039] Where: γ s —Specific gravity of whole tailings;

[0040] m1—mass of the pycnometer, g;

[0041] m2—mass of the pycnometer and the whole tailings, g;

[0042] m3—mass of pycnometer, whole tailings and water, g;

[0043] m4—mass of the pycnometer and water, g;

[0044] γ w —Specific gravity of distilled water, take 1.

[0045] The specific gravity of the whole tailings is obtained by taking the average value of three specific gravity tests, as shown in Table 1. It can be seen from the table that the specific gravity of the whole tailings is 2.96.

[0046] Table 1 Whole tailings specific gravity test results

[0047]

[0048] The experiment for determining the bulk density of whole tailings is as follows.

[0049] The bulk density of the whole tailings is measured according to the national standard for construction sand: GB / T 14684-2011, including the following steps:

[0050] 1. Place about 5 kg of sample in an enamel tray and dry it in a constant temperature oven at (105±5)℃ until constant weight;

[0051] 2. After cooling to room temperature, remove particles larger than 4.75 mm and divide the mixture into two equal portions for later use;

[0052] 3. Take a dry graduated cylinder and weigh it. Then take a portion of the sample dried in step 1 and slowly pour the sample into the cylinder from 50 mm above the center using a funnel or spoon. Allow the sample to fall freely. When the sample forms a heap on the top of the graduated cylinder and the cylinder is full, stop adding material. Then use a ruler to scrape the cylinder along the center line to both sides (avoid touching the cylinder during the test). Weigh the total mass of the sample and the graduated cylinder to the nearest 0.01 g.

[0053] 4. Take a dry density cylinder and weigh it. Then take a portion of the sample dried in step 1 and add it to the density cylinder with a spoon. Then use a rubber hammer to repeatedly hit it to make the whole tailings dense. Then use the whole tailings to fill the density cylinder. Use a rubber hammer to hit it again and fill it up with the whole tailings until the dense whole tailings fill the capacity cylinder. Weigh the total mass of the sample and the capacity cylinder to an accuracy of 0.01g.

[0054] The calculation formula of bulk density of whole tailings is as follows:

[0055]

[0056] Where: γ—bulk density of whole tailings, g / cm 3 ;

[0057] W1—weight of measuring cylinder, g;

[0058] W2—weight of measuring cylinder and whole tailings, g;

[0059] V—volume of measuring cylinder, ml.

[0060] The loose and compacted bulk densities of the whole tailings in this embodiment were obtained by taking the average value of three tests. The test results are shown in Table 3-2. After measurement, the loose bulk density of the whole tailings in this embodiment is 1.477t / m 3 , the dense bulk density is 1.933t / m 3 .

[0061] Table 2 Test results of loose and dense bulk density of full tailings

[0062]

[0063]

[0064] The experiment for determining the porosity of whole tailings is as follows.

[0065] The void ratio of the whole tailings is calculated according to the national standard for construction sand (GB / T 14684-2011), and the calculation formula is as follows.

[0066]

[0067] Where: η—void ratio of whole tailings, %;

[0068] γ—bulk density of whole tailings, g / cm 3 ;

[0069] γ s —Specific gravity of whole tailings, g / cm 3 .

[0070] Substituting the data in Table 1 and Table 2 into the above formula, the void ratio of the whole tailings in loose and dense states can be calculated, as shown in Table 3 below.

[0071] Table 3 Calculation results of the porosity of the whole tailings

[0072] Loose void ratio (%) Density void ratio (%) Whole tailings 50.9 35.8

[0073] The test for measuring the particle size distribution of the whole tailings is as follows.

[0074] The particle size composition of the whole tailings has a significant impact on mine filling. On the one hand, it affects the dehydration process of the whole tailings, and on the other hand, it affects the cementing performance and cementing agent consumption of the cemented filling body. Its main parameters are median diameter and particle unevenness coefficient. In this embodiment, the particle size test of the whole tailings was carried out using a Malvern MS3000 laser diffraction particle size analyzer. The measured particle size results of the whole tailings are as follows: Figure 1 For the sake of intuitiveness, the data of the whole tailings of the mountain were further analyzed to obtain Table 4.

[0075] Table 4 Whole tailings particle size composition

[0076]

[0077]

[0078] According to the results of particle size analysis, the main particle size parameters of the whole tailings are: d 10 =3.761μm (particle size at 10% content), d 50 =57.733 μm (particle size at 50% content), d 90 =273.037 μm (particle size with 90% content), d 100 =731.262 μm (particle size at 100% content), and the average particle size is 101.596 μm.

[0079] The whole tailings is composed of particles of different sizes, which can be expressed by the unevenness coefficient C. u and the curvature coefficient C c Characterizes the uniformity of the material's particle size composition. The calculation formula is as follows:

[0080] C u =d 60 / d 10

[0081] C c =d 30 2 / d 60 d 10

[0082] Among them, d 10 d 30 d 60 The diameters of the sieve holes through which particles with cumulative contents of 10%, 30%, and 60% can pass are respectively. Their values ​​can be found from the particle size composition curve. u The larger the value, the flatter the gradation curve, indicating that the particle size composition is more uneven, easy to be dense, and has a good gradation; C u The smaller the value, the steeper the gradation curve, indicating that the particle size composition is more uniform, difficult to compact, and poorly graded. u ≥5 and C c =1-3, the density of the whole tailings is better.

[0083] After calculation, the unevenness coefficient C u =25.32 and curvature coefficient C c =0.92, that is, the particle size distribution range of the whole tailings in this embodiment is large, but the gradation is poor. The particle size of the whole tailings sample taken in this test is within 731.262μm, the proportion of particles with a particle size less than 74μm (-200 mesh) is 53.39~56.53%, and the particle size range with a particle size proportion of 50% is below 58.880μm. According to the existing technology, in order to ensure that the filling material does not stratify and segregate during long-term transportation in the pipeline to form the so-called "paste structure flow", the proportion of the whole tailings -20μm particle size must be greater than 15%. In this embodiment, the proportion of the whole tailings -20μm particle content is about 30.83~32.66%. Therefore, the use of whole tailings as aggregate can ensure long-distance transportation of the filling material slurry.

[0084] Experiment on chemical composition analysis of whole tailings.

[0085] The results of chemical composition analysis of the whole tailings by spectral analysis are shown in Table 5. The test results show that the main components of the whole tailings are SiO2, Fe2O3, BaO and SO3, and the content of recoverable metals is low. It contains no or very little toxic and harmful substances, which meets the environmental protection requirements of underground filling and can be used as filling aggregate.

[0086] Table 5 Chemical element analysis results of whole tailings

[0087] chemical composition <![CDATA[SiO2]]> <![CDATA[Fe2O3]]> BaO <![CDATA[SO3]]> <![CDATA[Al2O3]]> CaO MgO <![CDATA[K2O]]> Proportion (%) 59.95 21.83 5.089 3.504 2.99 1.02 0.963 0.551 chemical composition MnO <![CDATA[TiO2]]> <![CDATA[Na2O]]> SrO CuO <![CDATA[P2O5]]> Cl <![CDATA[Y2O3]]> Proportion (%) 0.167 0.113 0.11 0.0579 0.0515 0.043 0.012 0.011

[0088] The single factor variable method was used to determine that the best flocculant for whole tailings was BKF06#, the best dosage was 10g / t, and the best dilution concentration was 10%.

[0089] The selected tests on flocculants are as follows.

[0090] Five organic flocculants were used to determine the optimal flocculant for whole tailings using a single-factor variable method. The experimental plan is shown in Table 6 below.

[0091] Table 6 Optimal test plan for flocculant types

[0092]

[0093] According to the test plan, a 10% mass concentration of full tailings slurry was prepared and a static flocculation sedimentation test was carried out using a 1000 mL graduated cylinder. The test results are as follows: Figure 2 From the test results, we can see that BKF06# has the best flocculation effect.

[0094] The flocculant used in this embodiment is BKF06#, which was developed and produced by Changsha Mining Research Institute. It is a type of existing organic flocculant. Its chemical composition is polyacrylamide, and its molecular formula is (CH2CHCONH2)n, where n represents the degree of polymerization. The higher the degree of polymerization, the better the flocculation effect is generally, but the higher the cost.

[0095] Based on the determination of the optimal type of flocculant, the optimal dilution concentration of the whole tailings slurry was determined by the single factor variable method. This experiment set a total of 5 levels of whole tailings slurry concentration, and the specific test plan is shown in Table 7.

[0096] Table 7 Test scheme for optimal dilution concentration of whole tailings mortar

[0097] Types of flocculants Flocculant dosage Concentration of whole tailings mortar (%) BKF06# 30g / t 10、12.5、15、17.5、20

[0098] The test results are as follows Figure 3 As shown in the figure, the test results show that as the concentration increases, the rate of flocculation and sedimentation slows down. When the concentration of the whole tailings slurry is 10%, the rate of change of the solid-liquid separation interface height over time is the largest, so the whole tailings concentration is selected to be 10%.

[0099] After determining the optimal type of flocculant and the optimal feed concentration of the tailings slurry, the optimal dosage of the optimal flocculant for the tailings was determined using the single-factor variable method. The test plan is shown in Table 8 below.

[0100] Table 8 Optimal flocculant dosage test plan

[0101] serial number Types of flocculants Whole tailings slurry concentration Flocculant dosage Group 1 BKF06# 10％ 5g / t Group 2 BKF06# 10％ 7.5g / t Group 3 BKF06# 10％ 10g / t Group 4 BKF06# 10％ 30g / t

[0102] Four groups of tailings mortars with a 10% mass concentration were prepared and subjected to static flocculation and sedimentation tests. The flocculant solution concentration was 0.5‰, and the flocculant dosages were 5g / t, 7.5g / t, 10g / t, and 30g / t, respectively. The test results show that as the flocculant dosage increased from 5g / t to 10g / t, the settling velocity of the tailings mortar increased continuously during the first 30 seconds, and the curvature of the settling height versus time curve increased. When the flocculant dosage increased from 10g / t to 30g / t, the settling velocity of the tailings mortar remained virtually unchanged. This may be because a higher flocculant dosage results in larger flocs, which face greater resistance from floating particles during the sinking process, thus affecting the settling velocity. It was also found that a flocculant dosage of 10g / t resulted in better overflow water clarity. Therefore, considering the settling rate, the optimal flocculant dosage is 10g / t.

[0103] In summary, through the single factor variable method, the optimal type of flocculant, the optimal dosage and the optimal dilution concentration of whole tailings mortar were determined to be BKF06#, 10g / t and 10%, respectively.

[0104] We designed strength tests for the filling material using different mix ratios and concentrations, determining the optimal mix ratio to be 4:1 cement:fly ash, with a slurry concentration of 74%. We also conducted water bleeding and shrinkage tests to ensure the water retention and stability of the filling material.

[0105] The strength tests of filling bodies with different proportions and concentrations are as follows.

[0106] Slump tests were carried out for different filling materials, different lime-sand ratios and different concentrations of cementitious filling materials. The test plan is shown in Table 9.

[0107] Table 9 Slump test plan

[0108]

[0109] The test results are shown in Tables 10 and 11.

[0110] Table 10 Slump test results (cement: fly ash = 4:1) Unit: cm

[0111]

[0112] Table 11 Slump test results (cement: fly ash = 6:4) Unit: cm

[0113]

[0114]

[0115] From the above test data, we can see that the slump value of the filling material increases with the decrease of slurry concentration, that is, the fluidity of the filling material is getting better and better. From the test data in Tables 10 and 11, we can see that the type and amount of cementitious materials have little effect on the slump.

[0116] According to the classification of concrete slump in the "GB50164-92" standard, the slump value of high-fluidity concrete transported by pump pressure should be no less than 16cm. However, the transportation of filling materials is different from that of concrete. The former involves long-distance and long-term transportation, and the filling area is generally large. Therefore, while considering the transportability of filling materials, attention should also be paid to leveling properties. Filling materials with better leveling properties can increase the filling rate of the mine and provide safety guarantees for the next step of mining.

[0117] Taking into account the differences between mine filling and concrete transportation, and combining with the engineering experience of other mine paste filling, the slump value of the filling material should be between 26 and 29 cm when selecting transportation, and the corresponding filling material concentration should be 72% to 76%.

[0118] The optimal strength test for cement and fly ash ratio is as follows.

[0119] According to the test results of filling slurry transportation performance, the filling slurry concentration of 74% was initially selected, the lime-sand ratio was selected at two levels of 1:6 and 1:15, and the ratio of cement and fly ash of cementitious materials was selected from four levels of 10:0, 4:1, 7:3, and 6:4. The strength of the filling body with different ratios was analyzed with the curing age (3d, 7d, and 28d). The test plan is shown in Table 12, and the strength test results are shown in Table 13. Figure 4 shown.

[0120] Table 12 Optimal test scheme for cement fly ash ratio

[0121]

[0122] Table 13 Cement fly ash ratio optimization test results

[0123]

[0124] From the test results, it can be found that the strength of the filling body increases with age and the amount of cementitious materials used. Under the same ash-sand ratio, as the proportion of fly ash in the cementitious material increases (from 0% to 40%), the 28d strength of the filling body tends to increase first and then decrease. When cement: fly ash = 4:1, the 28d strength of the filling body reaches its maximum. After the appropriate addition of fly ash, the later strength of the filling body will be improved, but as the fly ash content increases, the later strength of the filling body will also decrease. Since the cost of cementitious materials will decrease when the proportion of fly ash in the cementitious material increases, in order to ensure the strength of the filling body and control the filling cost, two ratios of cement: fly ash = 4:1 and cement: fly ash = 6:4 were selected for the next step of filling strength test with different concentrations.

[0125] The test on the proportion of filling materials is as follows.

[0126] According to the results of the strength test of the optimal cement-fly ash ratio, the cement-fly ash ratio was 4:1 and 6:4, the ash-sand ratio was 1:4, 1:6, 1:8, 1:10, 1:15, and 1:20, and the filling concentration was 72%, 74%, 76%, and 78%. The strength ratio test was carried out. The test plan is shown in Table 14, and the strength test results are shown in Table 15. Figure 5 shown.

[0127] Table 14 Comprehensive strength ratio test plan

[0128]

[0129]

[0130] Table 15 Overall strength ratio test results

[0131]

[0132]

[0133] From the above strength ratio test results, it can be analyzed that as the filling concentration increases, the strength of the test block also increases accordingly; the strength of the low lime-sand ratio test block does not increase much with age, and increasing the slurry concentration has a significant effect on improving the strength of the filling body.

[0134] The following is the test on water seepage and shrinkage of filling body.

[0135] The bleeding rate reflects the water retention properties of the filling material slurry and is actually also the segregation characteristic of the slurry. The bleeding rate is the phenomenon of water precipitation on the surface of the cementitious material after pouring and compaction but before solidification. A high bleeding rate can lead to slurry stratification, poor flow properties, and loss of cementitious materials, which is not conducive to regulating the slurry delivery time. On the other hand, an excessive bleeding rate of the filling material slurry not only increases the drainage workload but also worsens the underground working environment. At the same time, an excessively high bleeding rate means a lower filling and capping rate, which directly affects the underground work site environment and the safety and stability of the mine surface and surrounding structures. Therefore, a reasonable bleeding rate of the filling material slurry is a key factor in ensuring orderly underground mining and filling and safe and normal mine production.

[0136] According to the slump and strength mix ratio test results, lime-sand ratios of 1:4, 1:6, 1:8, 1:10, 1:15 and 1:20, cement: fly ash = 4:1 and 6:4, and slurry mass concentrations of 72%, 74%, 76% and 78% were selected for water bleeding rate tests, and the water bleeding and shrinkage of the filling materials were recorded. The test plan is shown in Table 16 below.

[0137] Table 16 Bleeding and Settling Test Scheme

[0138]

[0139] The results of the water seepage and sedimentation tests are shown in Table 17.

[0140]

[0141]

[0142] Test results indicate that at a slurry concentration of 74% (cement:fly ash = 4:1), both the water seepage rate and the shrinkage rate are less than 5%, preventing segregation during transportation. However, when the fly ash ratio reaches 40% (cement:fly ash = 6:4), the water seepage rate is excessive, potentially leading to segregation during transportation. However, the small amount of water exuded does not significantly affect the setting and hardening of the backfill material. The hardened backfill has a high capping rate (>95%), ensuring smooth mining operations.

[0143] The test for determining the filling material concentration is as follows.

[0144] Paste filling can increase the concentration of filling slurry, but the increase in filling concentration is not unlimited and must match the fluidity of the filling slurry to ensure that the paste concentration is within a reasonable delivery range. Figure 6It can be seen that when the slurry concentration is between 72% and 76%, the flow resistance of the slurry is small. When the slurry concentration exceeds 76%, the flow resistance increases sharply, that is, the rate of increase of the flow resistance of the slurry increases sharply, which will increase the difficulty of slurry transportation. Preferably, the optimal concentration range of the filling slurry is 74%.

[0145] The test for determining the filling material ratio is as follows.

[0146] According to the strength recommendation required for the filling body and the filling material strength test results, different ash-sand ratios that meet the filling strength are given at a concentration of 74%, namely cement:fly ash = 4:1 and cement:fly ash = 6:4.

[0147] When cement: fly ash = 4:1: for the top 2m of the first-step mine room, the filling strength requirement is 2MPa, and the recommended lime-sand ratio is 1:10; for the middle part, the filling strength requirement is 1.5MPa, and the recommended lime-sand ratio is 1:12.5; for the bottom 8m, the filling strength requirement is 3MPa, and the recommended lime-sand ratio is 1:8.5; for the top 2m of the second-step pillar, the filling strength requirement is 2MPa, and the recommended lime-sand ratio is 1:10; for the middle part, the filling strength requirement is 0.5MPa, and the recommended lime-sand ratio is 1:19; for the bottom 8m, the filling strength requirement is 2MPa, and the recommended lime-sand ratio is 1:10.

[0148] When cement: fly ash = 6:4: for the top 2m of the first-step mine room, the filling strength requirement is 2MPa, and the recommended ash-sand ratio is 1:8; for the middle part, the filling strength requirement is 1.5MPa, and the recommended ash-sand ratio is 1:10; for the bottom 8m, the filling strength requirement is 3MPa, and the recommended ash-sand ratio is 1:7; for the top 2m of the second-step mine pillar, the filling strength requirement is 2MPa, and the recommended ash-sand ratio is 1:8; for the middle part, the filling strength requirement is 0.5MPa, and the recommended ash-sand ratio is 1:15; for the bottom 8m, the filling strength requirement is 2MPa, and the recommended ash-sand ratio is 1:8.

[0149] For the filling strength requirements at different stope locations, the recommended table for different lime-sand ratios under two ratios is shown in Table 17.

[0150] Table 17 Recommended lime-sand ratios for different strengths under two mix ratios

[0151]

[0152]

[0153] According to the test results of water seepage and shrinkage of filling materials, when the slurry concentration is 74% and the ratio of cement to fly ash is 4:1, the water seepage rate and sedimentation rate of the filling slurry are both less than 5%. At this time, the slurry has good water retention and is not easy to stratify and segregate, so it can be used for underground filling; when the slurry concentration is 74% and the ratio of cement to fly ash is 6:4, the water seepage rate and shrinkage rate of the slurry are too large, the slurry is easy to stratify and segregate, which is not conducive to underground filling. Therefore, the cement to fly ash ratio of 4:1 is selected.

[0154] The present invention also provides a method for preparing underground mine filling materials using metallurgical solid waste, comprising the following steps:

[0155] S1. Use a thickener to dilute the whole tailings with water to a concentration of 10-12%;

[0156] S2. Add flocculant at a dosage of 10-15g / t to accelerate the sedimentation of the tailings;

[0157] S3. Add the whole tailings, slag silicate cement, fly ash and water into a mixer, and stir for 3 to 5 minutes at a time through a high-speed flexible activated stirring method to obtain a filling material.

Claims

1. An underground mine filling material prepared from metallurgical solid waste, characterized in that: The composition comprises the following components in parts by weight: 58-122 parts of slag silicate cement, 15-30 parts of fly ash, 1296-1377 parts of whole tailings, 509-510 parts of water, and 0.013-0.014 parts of flocculant.

2. The underground mine filling material prepared from metallurgical solid waste according to claim 1, characterized in that: The particle size distribution of the whole tailings is: Particle size 0-20 μm: 30.83-32.66%; Particle size 21-74 μm: 23.2-25.03%; Particle size 75-500μm: 43.47-45.61%.

3. The underground mine filling material prepared from metallurgical solid waste according to claim 1, characterized in that: The flocculant is polyacrylamide flocculant.

4. The underground mine filling material prepared from metallurgical solid waste according to claim 1, characterized in that: The specific gravity of the whole tailings is 2.96-3, and the loose bulk density is 1.477-1.5t / m 3 , dense bulk density is 1.933~2t / m 3 The loose void ratio of the whole tailings dry material is 50.9-51%, and the dense void ratio is 35.8-36%.

5. The underground mine filling material prepared from metallurgical solid waste according to claim 4, characterized in that: The chemical formula of the flocculant is (CH2CHCONH2)n.

6. The underground mine filling material prepared from metallurgical solid waste according to claim 1, characterized in that: The flocculant dosage is 10-15 g / t.

7. The underground mine filling material prepared from metallurgical solid waste according to claim 1, characterized in that: The mass ratio of the slag silicate cement to fly ash is 4-5:

1.

8. The underground mine filling material prepared from metallurgical solid waste according to claim 1, characterized in that: The slurry concentration of the filling material is 74-80%.

9. The method for preparing underground mine filling material according to any one of claims 1 to 8, characterized in that: The steps include: S1. Use a thickener to dilute the whole tailings with water to a concentration of 10-12%; S2. Add flocculant at a dosage of 10-15g / t to accelerate the sedimentation of the tailings; S3. Add the whole tailings, slag silicate cement, fly ash and water into the mixer in sequence, and stir for 3 to 5 minutes at a time through a high-speed flexible activated stirring method to obtain a filling material.

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