Flow-state solidified soil based on tail mud of water treatment plant and preparation method of flow-state solidified soil

Abstract

The invention relates to the technical field of solid waste utilization, in particular to flow-state solidified soil based on water treatment plant tail mud and a preparation method of the flow-state solidified soil, and the flow-state solidified soil comprises the following components in parts by mass: 10-80 parts of water treatment plant tail mud, 50-100 parts of muck and 16-28 parts of a solidifying material. According to the flow-state solidified soil based on the water purification plant tail mud and the preparation method of the flow-state solidified soil, a mix proportion design and calculation method based on compound doping of the water purification plant tail mud and the high-density soil material in the muck is provided, and the problems that the flow-state solidified soil prepared from the water purification plant tail mud is high in viscosity and lack of fluidity, and the high-density soil material seeps and sinks can be solved; and the quality of the flow-state solidified soil is improved, and the construction waste source reduction and the resource utilization rate are improved.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste utilization, and in particular to a fluidized solidified soil based on tailings of a water treatment plant and a preparation method thereof. Background Art

[0002] With the "siphon effect" of large and medium-sized cities becoming prominent, the population of central cities growing rapidly and the construction of urban lifeline projects accelerating, the demand for drinking water is also increasing, and the number of water treatment plants is increasing. Conventional aluminum salts are coagulants used for water purification, and due to their effectiveness and low cost, they have become the most commonly used main flocculants in the water treatment industry around the world. Therefore, a large amount of by-products will be generated through water purification - water treatment plant tailings. It is composed of high content of Al2O3 and SiO2, similar to conventional clay soil.

[0003] At present, the main methods of disposing tailings from water treatment plants are landfill, incineration, sedimentation in sedimentation tanks, etc. Some studies have also applied it to resource applications such as the preparation of ceramic tiles and cement clinker. The traditional method of disposing tailings is costly, with a disposal fee of more than 300 yuan per cubic meter. At the same time, as the amount of tailings added increases, the bending strength of ceramic tiles will decrease, and due to the presence of organic matter, it will hinder the hydration and hardening of cement, thereby reducing the compressive strength. Therefore, to a certain extent, the resource utilization rate of tailings from water treatment plants is relatively low, the disposal cost is high, and there are few storage sites, resulting in a waste of soil resources and failing to fundamentally eliminate the adverse effects on the environment.

[0004] In addition, with the continuous progress of urban infrastructure construction in my country, earthwork backfill engineering has become a crucial link in the construction process of foundations and various underground facilities, and the scope of backfilling covers a wide range, such as: foundation pit backfilling, fertilizer tank backfilling, pipeline backfilling, roadbed backfilling, etc. In the past, a large amount of natural graded sand and gravel coarse and fine aggregates were consumed in the backfilling process of engineering construction. Graded sand and gravel are non-renewable resources. If they are not used sparingly, they will be exhausted sooner or later. For the axilla corners between the horizontal diameter of the pipeline and the bottom foundation of the pipe, the gap between the traditional backfill materials is too narrow, and it is difficult for both manpower and equipment to play their advantages, and it is difficult to ensure the backfill quality. Poor backfill quality at the axilla corners will cause the pipeline to be emptied, thereby causing deformation and ultimately reducing the service life of the pipeline. Today's pipeline projects have become more and more complicated, and it is inevitable that new and old pipelines are laid crosswise. When laying new pipelines around old pipelines, the fill around the old pipelines will always be disturbed, and the secondary excavation of backfilling needs to be considered.

[0005] At present, there are few studies on the solidification and improvement of the typical characteristics of water treatment plant tailings, such as small particle size, high water content, and high organic matter content. In particular, no one has involved the mix ratio design and calculation method for preparing fluidized solidified soil based on the resource utilization of water treatment plant tailings. If solidification and improvement are only carried out by adding cement, it is easy to hinder the hydration of cement and prolong the setting time. At the same time, the strength is low and the resistance to dry-wet cycles is poor. If only density-adjusted soil materials such as sandy soil, gravel sand soil, pebble gravel soil, and medium-to-strong weathering rock soil are used to prepare fluidized solidified soil, in order to make it highly fluid, there will be more free water in the slurry, resulting in a higher water seepage rate. At the same time, the heavy components sink, causing uneven shrinkage and surface cracking. Summary of the invention

[0006] The purpose of the present invention is to provide a fluidized solidified soil based on tailings from a water treatment plant and a preparation method thereof, and to provide a mix ratio design and calculation method based on the composite blending of tailings from a water treatment plant with high-density soil materials in slag soil, which can solve the problems of high viscosity, lack of fluidity and water seepage and shrinkage of high-density soil materials in preparing fluidized solidified soil from tailings from a water treatment plant, and improve the quality of the fluidized solidified soil, thereby increasing the source reduction and resource utilization rate of construction waste.

[0007] To achieve the above object, the present invention provides a fluidized solidified soil based on tailings from a water treatment plant, wherein the components include 10-80 parts of tailings from a water treatment plant, 50-100 parts of slag and 16-28 parts of solidified materials by mass.

[0008] Preferably, the components in the solidifying material are, by mass percentage, 15-32% cement, 31-32% mineral powder, 22-38% fly ash, 4-5% calcium hydroxide, 7-12% calcium sulfate, 1-2% surfactant and 1-2% water reducing agent.

[0009] Preferably, the components include 40-65 parts of water treatment plant tailings, 65-80 parts of slag and 20-25 parts of solidified materials in terms of mass fraction.

[0010] Preferably, the components in the solidifying material are, by mass percentage, 21-26% cement, 31-32% mineral powder, 26-32% fly ash, 4-5% calcium hydroxide, 8-11% calcium sulfate, 1% surfactant and 1% water reducing agent.

[0011] The above-mentioned method for preparing fluidized solidified soil based on tailings of a water treatment plant comprises the following steps:

[0012] S1. Draw a mud wet density-flow value-28d compressive strength graph with mud wet density as the abscissa and flow value and 28d compressive strength as the ordinates;

[0013] S2. According to the flow value and 28d compressive strength in the construction requirements, select the superimposed shaded area 1 in the mud wet density-flow value-28d compressive strength diagram obtained in S1, and select the maximum value of the mud wet density in the superimposed shaded area 1;

[0014] S3, draw a solidified material-flow value-compressive strength graph with the solidified material mass as the abscissa and the flow value and 28d compressive strength as the ordinates;

[0015] S4. According to the flow value and 28d compressive strength in the construction requirements, select the second overlapping shaded area in the solidified material-flow value-compressive strength diagram obtained in S3, and select the minimum value of the solidified material mass in the second overlapping shaded area;

[0016] S5. Determine the initial water content of the tailings of the water treatment plant and the initial water content of the slag soil, respectively, and calculate the mass of the tailings of the water treatment plant, the mass of the slag soil, the theoretical water consumption, and the additional water consumption required for each cubic meter of fluidized solidified soil at the wet density of the mud obtained in S2;

[0017] S6, according to the weight of the tailings sludge of the water treatment plant calculated in S5 and the amount of water to be added, the two are put into a ball mill for desludge, and after desludge is completed, the two are put into a slurry storage tank for further stirring;

[0018] S7, adding slag to the slurry storage tank in S6 according to the slag mass calculated in S5, and measuring the wet density of the slurry after continuous stirring;

[0019] S8, calculating an error value based on the actual measured value of the mud wet density obtained in S7 and the maximum value of the mud wet density in S2, and selecting whether to add slag or water based on the error value to obtain a final mixed mud;

[0020] S9, extract the mixed mud in S8, add the solidifying material and stir, stir evenly to obtain fluidized solidified soil.

[0021] Preferably, in S5, the calculation of theoretical water consumption is as follows:

[0022]

[0023] Among them, M w is the theoretical water consumption, G s M is the specific gravity of soil particles after the tailings and slag of the water treatment plant are mixed, c G is the amount of curing material added, c is the specific gravity of the solidified material, ρ t is the wet density of mud.

[0024] Preferably, in S5, the total mass of the tailings and slag of the water treatment plant is calculated as follows:

[0025] M s=ρ t ×1000-M w -M c ;

[0026] Among them, M s is the total mass of tailings and slag from the water treatment plant;

[0027] The quality of tailings sludge from water treatment plant M s1 The calculation of is as follows,

[0028]

[0029] The mass of the soil M s2 The calculation of is as follows,

[0030]

[0031] Among them, ω1 is the measured value of the initial water content in the tailings of the water treatment plant, ω2 is the measured value of the initial water content in the slag, and P is the mixing ratio of the tailings and slag of the water treatment plant.

[0032] Preferably, in S5, an additional amount of water M is required. w1 As shown below,

[0033]

[0034] Preferably, in S8, when the error value is within 0-5%, no slag or water needs to be added;

[0035] If the error value exceeds 0-5%, if the actual measured value of the mud wet density is too small, add slag; if the actual measured value of the mud wet density is too large, add water.

[0036] Preferably, in S9, the stirring time is 45-60s.

[0037] Therefore, the present invention adopts the above-mentioned fluidized solidified soil based on tailings of a water treatment plant and its preparation method, and its beneficial effects are:

[0038] 1. The present invention provides a design and calculation method for the mix ratio of water treatment plant tailings and high-density soil materials in the slag, which can not only solve the problems of high viscosity, lack of fluidity and water seepage and shrinkage of high-density soil materials in preparing fluidized solidified soil from water treatment plant tailings, but also improve the quality of fluidized solidified soil and improve the source reduction and resource utilization rate of construction waste;

[0039] 2. The present invention uses a compound of tailings sludge from a water treatment plant and slag to prepare fluidized solidified soil, and uses the fluidized solidified soil to replace traditional trench backfill materials, thereby improving the recycling rate of tailings sludge from the water treatment plant and reducing treatment costs.

[0040] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a diagram of mud wet density-flow value-28d compressive strength in Example 1 of the present invention;

[0042] Figure 2 is a graph of solidified material-flow value-compressive strength in Example 1 of the present invention;

[0043] Figure 3 This is a flow chart of Embodiment 1 of the present invention. DETAILED DESCRIPTION

[0044] The present invention is further described below in conjunction with the accompanying drawings and embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs. The above-mentioned features or features mentioned in the specific examples mentioned in the present invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0045] Example 1

[0046] like Figure 3 As shown, a method for preparing fluidized solidified soil based on tailings of a water treatment plant comprises the following steps:

[0047] S1. Draw a mud wet density-flow value-28d compressive strength graph with mud wet density as the horizontal axis and flow value and 28d compressive strength as the vertical axis, such as Figure 1 shown.

[0048] S2. According to the construction requirements of flow value 120-160 mm and 28d compressive strength 0.6 MPa, select the superimposed shaded area 1 in the mud wet density-flow value-28d compressive strength diagram obtained in S1, and select the maximum value of the mud wet density in the superimposed shaded area 1, ρ t =1.65t / m 3 .

[0049] S3. Draw a graph of solidified material-flow value-compressive strength with the mass of solidified material as the horizontal axis and the flow value and 28d compressive strength as the vertical axis, such as Figure 2 shown.

[0050] S4. According to the flow value and 28d compressive strength in the construction requirements, select the second overlapping shaded area in the solidified material-flow value-compressive strength diagram obtained in S3, and select the minimum value of the solidified material mass in the second overlapping shaded area, M c =150kg.

[0051] S5. The initial water content of the tailings of the water treatment plant was ω1, which was 80%, and the initial water content of the slag was ω2, which was 15%. The specific gravity of the soil particles was tested according to GB / T 50123 "Standard for Geotechnical Test Methods". At this time, the specific gravity of the soil particles G s =2.579, specific gravity of solidified material G c =3.0.

[0052] Calculate the mass of tailings from the water treatment plant, the mass of slag, the theoretical water consumption and the additional water required for each cubic meter of fluidized solidified soil at the wet density of the mud obtained in S2;

[0053] In S5, the theoretical water consumption is calculated as follows:

[0054]

[0055] Among them, M w is the theoretical water consumption, G s M is the specific gravity of soil particles after the tailings and slag of the water treatment plant are mixed, c G is the amount of curing material added, c is the specific gravity of the solidified material, ρ t is the wet density of mud.

[0056] In S5, the total mass of the tailings and slag from the water treatment plant is calculated as follows:

[0057] M s =ρ t ×1000-M w -M c =1650-602-150=898kg;

[0058] Among them, M s It is the total mass of tailings sludge and slag from the water treatment plant.

[0059] The quality of tailings sludge from water treatment plant M s1 The calculation of is as follows,

[0060]

[0061] The mass of the soil M s2 The calculation of is as follows,

[0062]

[0063] Among them, ω1 is the measured value of the initial water content in the tailings of the water treatment plant, ω2 is the measured value of the initial water content in the slag, and P is the mixing ratio of the tailings and slag of the water treatment plant.

[0064] In S5, since the tailings and slag of the water treatment plant contain water, it is necessary to deduct this water content from the theoretical water consumption to calculate the additional water required. The additional water required M w1 As shown below,

[0065]

[0066] S6. According to the mass of tailings sludge from the water treatment plant calculated in S5 and the amount of water required to be added, the two are put into a ball mill for desludge. After desludge is completed, the tailings sludge is put into a slurry storage tank for further stirring.

[0067] S7. Add the slag to the slurry storage tank in S6 according to the slag mass calculated in S5. After continuous stirring, measure the wet density of the slurry. The actual measured value of the wet density of the slurry is 1.66t / m 3 .

[0068] S8, calculating the error value of 1% based on the actual measured value of the mud wet density obtained in S7 and the maximum value of the mud wet density in S2, and choosing whether to add slag or water based on the error value to obtain the final mixed mud;

[0069] In S8, when the error value is within 0-5%, no slag or water needs to be added;

[0070] If the error value exceeds 0-5%, if the actual measured value of the mud wet density is too small, add slag; if the actual measured value of the mud wet density is too large, add water to adjust the error value to within 0-5%.

[0071] S9. Draw out the mixed mud in S8, add the solidifying material and stir for 50 seconds until it is evenly stirred to obtain fluidized solidified soil.

[0072] Among them, the composition of the solidifying material is: 36kg of cement, 48kg of mineral powder, 42kg of fly ash, 6kg of calcium hydroxide, 15kg of calcium sulfate, 1.5kg of surfactant and 1.5kg of water reducing agent.

[0073] Comparative Example 1

[0074] The difference from Example 1 is that the mass of the tailings of the water treatment plant added is 1500 kg, no slag soil is added and no additional water is required, and the rest is the same as in Example 1 to obtain fluidized solidified soil.

[0075] Comparative Example 2

[0076] The difference from Example 1 is that the mass of the added slag is 1032 kg, the amount of water required to be added is 465 kg, no water treatment plant tailings are added, and the rest is the same as in Example 1, and fluidized solidified soil is obtained.

[0077] Test Example 1

[0078] The flowability, water seepage rate and 28d compressive strength of the fluidized solidified soil in Example 1 and Comparative Examples 1-2 were tested, and the results are shown in Table 1.

[0079] Table 1, Performance data of fluidized solidified soil in Example 1 and Comparative Examples 1-2

[0080]

[0081] Therefore, the present invention adopts the above-mentioned fluidized solidified soil based on water treatment plant tailings and its preparation method, and provides a mix ratio design and calculation method based on the complex blending of water treatment plant tailings and high-density soil in slag, which can not only solve the problems of high viscosity, lack of fluidity and water seepage and shrinkage of high-density soil in the preparation of fluidized solidified soil from water treatment plant tailings, but also improve the quality of the fluidized solidified soil and improve the source reduction and resource utilization rate of construction waste.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A fluidized solidified soil based on tailings from a water treatment plant, characterized in that: The components include 10-80 parts of tailings sludge from a water treatment plant, 50-100 parts of slag and 16-28 parts of solidified materials in terms of mass proportion.

2. The fluidized solidified soil based on tailings from a water treatment plant according to claim 1, characterized in that: The components in the solidifying material are calculated by mass percentage as follows: 15-32% cement, 31-32% mineral powder, 22-38% fly ash, 4-5% calcium hydroxide, 7-12% calcium sulfate, 1-2% surfactant and 1-2% water reducing agent.

3. The fluidized solidified soil based on tailings from a water treatment plant according to claim 1, characterized in that: The components include 40-65 parts of water treatment plant tailings, 65-80 parts of slag and 20-25 parts of solidified materials by mass.

4. The fluidized solidified soil based on tailings from a water treatment plant according to claim 2, characterized in that: The components in the solidifying material are calculated by mass percentage as follows: 21-26% cement, 31-32% mineral powder, 26-32% fly ash, 4-5% calcium hydroxide, 8-11% calcium sulfate, 1% surfactant and 1% water reducing agent.

5. A method for preparing fluidized solidified soil based on tailings from a water treatment plant according to any one of claims 1 to 4, characterized in that: The following steps are included: S1. Draw a mud wet density-flow value-28d compressive strength graph with mud wet density as the abscissa and flow value and 28d compressive strength as the ordinates; S2. According to the flow value and 28d compressive strength in the construction requirements, select the superimposed shaded area 1 in the mud wet density-flow value-28d compressive strength diagram obtained in S1, and select the maximum value of the mud wet density in the superimposed shaded area 1; S3, draw a solidified material-flow value-compressive strength graph with the solidified material mass as the abscissa and the flow value and 28d compressive strength as the ordinates; S4. According to the flow value and 28d compressive strength in the construction requirements, select the second overlapping shaded area in the solidified material-flow value-compressive strength diagram obtained in S3, and select the minimum value of the solidified material mass in the second overlapping shaded area; S5. Determine the initial water content of the tailings of the water treatment plant and the initial water content of the slag soil, respectively, and calculate the mass of the tailings of the water treatment plant, the mass of the slag soil, the theoretical water consumption, and the additional water consumption required for each cubic meter of fluidized solidified soil at the wet density of the mud obtained in S2; S6, according to the weight of the tailings sludge of the water treatment plant calculated in S5 and the amount of water to be added, the two are put into a ball mill for desludge, and after desludge is completed, the two are put into a slurry storage tank for further stirring; S7, adding slag into the slurry storage tank in S6 according to the slag mass calculated in S5, and measuring the wet density of the slurry after continuous stirring; S8, calculating an error value based on the actual measured value of the mud wet density obtained in S7 and the maximum value of the mud wet density in S2, and selecting whether to add slag or water based on the error value to obtain a final mixed mud; S9, extract the mixed mud in S8, add the solidifying material and stir, stir evenly to obtain fluidized solidified soil.

6. The method for preparing fluidized solidified soil based on tailings of a water treatment plant according to claim 5, characterized in that: In S5, the theoretical water consumption is calculated as follows: Among them, M w is the theoretical water consumption, G s M is the specific gravity of soil particles after the tailings and slag of the water treatment plant are mixed, c G is the amount of curing material added, c is the specific gravity of the solidified material, ρ t is the wet density of mud.

7. The method for preparing fluidized solidified soil based on tailings of a water treatment plant according to claim 6, characterized in that: In S5, the total mass of the tailings and slag from the water treatment plant is calculated as follows: M s =ρ t ×1000-M w -M c ; Among them, M s is the total mass of tailings and slag from the water treatment plant; The quality of tailings sludge from water treatment plant M s1 The calculation of is as follows, The mass of the soil M s2 The calculation of is as follows, Among them, ω1 is the measured value of the initial water content in the tailings of the water treatment plant, ω2 is the measured value of the initial water content in the slag, and P is the mixing ratio of the tailings and slag of the water treatment plant.

8. The method for preparing fluidized solidified soil based on tailings of a water treatment plant according to claim 7, characterized in that: In S5, additional water M is required w1 As shown below, 9. The method for preparing fluidized solidified soil based on tailings of a water treatment plant according to claim 5, characterized in that: In S8, when the error value is within 0-5%, there is no need to add slag or water; If the error value exceeds 0-5%, if the actual measured value of the mud wet density is too small, add slag; if the actual measured value of the mud wet density is too large, add water.

10. The method for preparing fluidized solidified soil based on tailings of a water treatment plant according to claim 5, characterized in that: In S9, the stirring time is 45-60s.

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