Iron tailing mud-based high-flow-state filling material and preparation method thereof

Abstract

The invention provides an iron tailing mud-based high-flow-state filling material and a preparation method, and belongs to the technical field of civil engineering materials, the filling material comprises the following raw materials by weight: 160-200 parts of iron tailing wet mud, 8-15 parts of slag powder, 3-8 parts of steel slag powder, 1-3 parts of quicklime powder, 0.3-0.8 part of a dispersant, 1-2 parts of a slurry stabilizer, and 0.5-1.0 part of a setting and hardening regulator. By means of the method, the problems that in the prior art, high-water-content tailing mud needs to be stored after being dewatered, the dewatering cost is high, stacking after dewatering still occupies space resources, and potential safety hazards exist can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering materials, and more specifically, to an iron tailings mud-based high-fluidity filling material and a preparation method thereof. Background Art

[0002] Iron tailings sand comes from the development of iron mines and is solid waste discharged after iron ore is crushed, ground, and sorted. The treatment process generates a large amount of tailings mud with high moisture content, and in many cases, the moisture content is as high as over 15%. If further dehydration treatment is carried out, not only the treatment cost is increased, but also the stacked dehydrated materials still occupy space resources and pose safety hazards.

[0003] However, in the current existing technologies, there is a lack of an effective solution to solve the problems such as high cost caused by the need to store the tailings mud with high moisture content after dehydration, and the still occupied space resources and safety hazards during the stacked storage after dehydration.

[0004] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present invention, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0005] In view of the above problems, the purpose of the present invention is to provide an iron tailings mud-based high-fluidity filling material and a preparation method thereof, so as to solve the problems in the prior art that the tailings mud with high moisture content needs to be stored after dehydration, resulting in high dehydration costs, still occupying space resources during the stacked storage after dehydration, and having safety hazards.

[0006] The present invention provides an iron tailings mud-based high-fluidity filling material, including the following raw materials in parts by weight:

[0007] 160 - 200 parts of wet iron tailings mud, 8 - 15 parts of slag powder, 3 - 8 parts of steel slag powder, 1 - 3 parts of quicklime powder, 0.3 - 0.8 part of dispersant, 1 - 2 parts of slurry stabilizer, 0.5 - 1.0 part of setting and hardening regulator.

[0008] In addition, preferably, the moisture content of the wet iron tailings mud is 15% - 30%.

[0009] In addition, preferably, the weight ratio of the wet iron tailings mud in the iron tailings mud-based high-fluidity filling material is greater than 80%.

[0010] In addition, preferably, the particle size of the wet iron tailings mud is <100 μm, and the specific surface area is >600 m 2 / kg.

[0011] In addition, preferably, the dispersant is sodium hexametaphosphate or polycarboxylate water reducer or a composition of sodium hexametaphosphate and polycarboxylate water reducer mixed in any proportion.

[0012] In addition, preferably, the slurry stabilizer is bentonite powder or sodium carboxymethyl cellulose or a composition of bentonite powder and sodium carboxymethyl cellulose mixed in any proportion.

[0013] In addition, preferably, the setting and hardening regulator is any one of sodium silicate and sodium sulfate or a composition mixed in any proportion.

[0014] The present invention also provides a preparation method of the iron tailings mud-based high-fluidity filling material as described above, comprising the following steps:

[0015] Mix 8 - 15 parts of slag powder, 3 - 8 parts of steel slag powder, and 1 - 3 parts of quicklime powder evenly to obtain the gelling material powder A;

[0016] Add 0.3 - 0.8 part of dispersant, 1 - 2 parts of slurry stabilizer, and 0.5 - 1.0 part of setting and hardening regulator to the gelling material powder A and mix evenly to obtain powder B;

[0017] Stir 160 - 200 parts of wet iron tailings mud, and add the powder B during the stirring process, and stir until the preset time to obtain the iron tailings mud-based high-fluidity filling material.

[0018] In addition, preferably, during the process of mixing 8 - 15 parts of slag powder, 3 - 8 parts of steel slag powder, and 1 - 3 parts of quicklime powder evenly to obtain the gelling material powder A,

[0019] Mix 8 - 15 parts of slag powder, 3 - 8 parts of steel slag powder, and 1 - 3 parts of quicklime powder evenly by mechanical stirring.

[0020] In addition, preferably, during the process of stirring 160 - 200 parts of wet iron tailings mud, adding the powder B during the stirring process, and stirring until the preset time to obtain the iron tailings mud-based high-fluidity filling material,

[0021] First, conduct forced stirring on the wet iron tailings mud for 3 - 5 minutes, and then add the powder B;

[0022] The preset time is 8 - 10 minutes.

[0023] As can be seen from the above technical solutions, the iron tailings mud-based high-fluidity filling material and its preparation method provided by the present invention use iron tailings wet mud as the main material of the high-fluidity filling material. The high-moisture-content tailings mud does not need to be dehydrated and stored, greatly saving the dehydration cost, and effectively solving the problems of difficult storage and environmental pollution caused by the stacking of a large amount of iron tailings. Using solid waste powders such as slag powder, steel slag powder, and quicklime powder as the cementitious material components of the filling material, replacing the use of high-consumption materials such as cement clinker, realizing the high-value utilization of solid waste resources. And under the synergistic effect of the solid waste powder as the cementitious material component, the dispersant, the slurry stabilizer, and the setting and hardening regulator, the prepared high-fluidity filling material has the advantages of uniform texture, excellent fluidity, self-leveling filling with swelling property, no water bleeding and no settlement after filling, and no shrinkage after setting and hardening. It can be used for the filling construction of various foundation pits and mine pits, thus realizing the large-scale resource utilization of a large amount of waste resources, and having good social and economic benefits and resource and environmental benefits.

[0024] To achieve the above and related purposes, and one or more aspects of the present invention include the features detailed hereinafter. The following description and the accompanying drawings detail certain exemplary aspects of the present invention. However, these aspects merely indicate some of the various ways in which the principles of the present invention can be used. In addition, the present invention is intended to cover all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] By referring to the following description in conjunction with the accompanying drawings, and with a more complete understanding of the present invention, other objects and results of the present invention will become more apparent and easier to understand.

[0026] Figure 1 It is a flowchart of the iron tailings mud-based high-fluidity filling material according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In the following description, for the purpose of illustration, in order to provide a comprehensive understanding of one or more embodiments, many specific details are set forth. However, it is obvious that these embodiments can also be implemented without these specific details.

[0028] In view of the problems in the prior art mentioned above, that is, the tailings mud with high moisture content needs to be dehydrated and stored, which has high dehydration cost, still occupies space resources after dehydration and stacking, and has potential safety hazards, an iron tailings mud-based high-fluidity filling material and its preparation method are proposed.

[0029] The following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings.

[0030] To illustrate the iron tailings mud-based high-fluidity filling material and its preparation method provided by the present invention, Figure 1Shows the process of iron tailings mud-based high-fluidity filling material according to an embodiment of the present invention.

[0031] The iron tailings mud-based high-fluidity filling material provided by the present invention comprises raw materials in the following weight parts:

[0032] 160 - 200 parts of wet iron tailings mud, 8 - 15 parts of slag powder, 3 - 8 parts of steel slag powder, 1 - 3 parts of quicklime powder, 0.3 - 0.8 part of dispersant, 1 - 2 parts of slurry stabilizer, 0.5 - 1.0 part of setting and hardening regulator.

[0033] Specifically, the stacking of iron tailings sand requires dehydration treatment, which not only increases the treatment cost, but also the stacked sand still occupies space resources and has potential safety hazards after dehydration. However, there is a lack of an effective solution in the prior art to effectively solve the above problems existing in iron tailings sand.

[0034] Therefore, the present invention uses wet iron tailings mud as the main material of the high-fluidity filling material, and completely replaces industrial cement clinker with solid wastes such as slag powder, steel slag powder and quicklime powder as the cementitious material components to prepare the high-fluidity filling material, so as to achieve a large amount of consumption of wet iron tailings mud, solve the problems of increased cost and occupied space resources caused by dehydration storage, and achieve a high utilization rate of various solid waste resources including iron tailings, slag powder, steel slag powder, etc. Moreover, the prepared high-fluidity filling material has high fluidity, does not require vibration under its own weight, and realizes self-compacting structure filling and backfilling through swelling and self-leveling spreading filling, which can solve the construction operation in limited space, ensure the safety of construction personnel in the filling operation area, and is especially suitable for filling in special-shaped, narrow spaces and pipe trenches. Therefore, it can be used as backfilling material for various large-scale building pits and mined-out areas of mines. The present invention provides a new way for the resource recycling of tailings and has good environmental and economic benefits.

[0035] As a preferred embodiment of the present invention, the moisture content of the wet iron tailings mud is 15% - 30%.

[0036] Specifically, the wet iron tailings mud used in the present invention is derived from the remaining part (i.e., tailings slurry) after separating useful iron minerals from iron ore through crushing, grinding, magnetic separation, flotation, etc. After concentration, precipitation and filtration, the iron tailings mud used in the present invention is obtained and directly used in the high-fluidity filling material without further drying treatment. The particle size distribution of the dried iron tailings mud is that the weight ratio of <0.088mm is about 22%, the weight ratio of 0.1mm - 0.088mm is about 24%, the weight ratio of 0.315mm - 0.1mm is about 48%, the weight ratio of 0.4mm - 0.315mm is about 6%, and the moisture content is about 15 - 30%.

[0037] As a preferred embodiment of the present invention, the weight ratio of the wet iron tailings mud to the high-fluidity filling material based on iron tailings mud is greater than 80%.

[0038] Specifically, by using the wet iron tailings mud as the main material of the high-fluidity filling material, with its proportion being greater than 80%, a large amount of wet iron tailings mud can be consumed.

[0039] As a preferred embodiment of the present invention, the particle size of the wet iron tailings mud is < 100 μm, and the specific surface area is > 600 m 2 / kg.

[0040] It should be noted that: the particle size of the wet iron tailings mud is preferably but not limited to < 100 μm, and the specific surface area is preferably but not limited to > 600 m 2 / kg.

[0041] The wet iron tailings mud is a solid waste discharged after the iron ore containing is crushed, ground, sorted, etc. The treatment process brings a large amount of tailings sand and mud with high water content, and the water content is as high as 15 - 30%; its main mineral phases are quartz and hematite phases, and there are also a small amount of kaolin, mica phase, chlorite, calcite, etc. Except that some components such as kaolin have potential activity and can polymerize with other components to form a gel structure conducive to the development of material strength, the wet iron tailings mud acts as the main material of the high-fluidity filling material.

[0042] The slag powder is an industrial waste mainly composed of calcium silicoaluminate, and the proportion of CaO, SiO 2 and Al 2 O 3 is about 85% or more, and most of it is vitreous, having potential hydraulic cementitious properties. The calcium-containing continuous phase in the slag is unstable and easily reacts with water in an alkaline environment; and in an alkaline environment, the slag powder can form stable gel network structures such as C-S-H and C-A-H. The slag powder can also react with the hydration products Ca(OH) 2 of steel slag and quicklime to generate low-calcium type hydrated calcium silicate gel through the "secondary hydration reaction"; thus, in an environment containing both steel slag and slag, the two can mutually stimulate and promote hydration, producing a composite superposition effect, improving the density and increasing the material strength. In addition, the slag powder particles are relatively fine. After replacing cement, the cementitious material has a better particle size distribution, forming a dense filling structure and a self-compacting packing system at the mesoscopic level; at the same time, it can also reduce the water consumption, improve the fluidity and cohesion, and prevent bleeding and segregation.

[0043] The main minerals of the steel slag powder are olivine, magnesium rosaniline, C 2 S, C 3 S, C 4 AF, C 2F, CaO-FeO-MnO-MgO solid solution, and free CaO, where C 2 S, C 3 S, RO phase are the main substances. C 2 S, C 3 S is the main active component in steel slag powder, and C-S-H gel and Ca(OH) 2 are the most important hydration products of steel slag. Under the action of chemical activators, the internal substances in steel slag powder are activated into highly active small molecules. As the hydration reaction proceeds, hydrated calcium silicate, ettringite and other gel structures with cementitious properties are polymerized and formed.

[0044] Quicklime powder is a white powdery substance, and its main components are CaO and MgO. After quicklime powder is introduced into the fluidized solidification material, it reacts with water to produce calcium hydroxide, which is beneficial to form an alkaline environment inside the material and provides a calcium source for the formation of a stable hydrated calcium silicate gel structure of slag powder and steel slag powder, helping the material to be more firmly cemented and improving its durability. In addition, quicklime powder has expansibility, which can fill the micropores in the filling material, reduce the shrinkage and cracking of the filling material; it can make the filling material softer and more plastic, and improve the pourability and plasticity of the filling material.

[0045] As a preferred embodiment of the present invention, the dispersant is sodium hexametaphosphate or polycarboxylate water reducer or a composition of sodium hexametaphosphate and polycarboxylate water reducer mixed in any proportion.

[0046] Specifically, the incorporation of a dispersant such as sodium hexametaphosphate or polycarboxylate can reduce the interfacial tension between particles, making the fine particles of tailings mud maintain a relatively dispersed state. This is the key component for converting cohesive iron tailings wet mud and other components into a homogeneous mixture and forming a highly fluid slurry state. During the external stirring process, the phosphate dispersant can form stable complexes with metal ions such as calcium ions and magnesium ions in the slurry. These complexes have good solubility in water and will not settle on the particle surface, preventing the mutual aggregation and agglomeration of particles. The polycarboxylate dispersant contains a large number of carboxyl ion groups, which make the particle surface negatively charged after ionization in water. When the negatively charged particles approach each other, the electrostatic repulsion will keep them at a certain distance, thus achieving the dispersion effect.

[0047] As a preferred embodiment of the present invention, the slurry stabilizer is bentonite powder or sodium carboxymethylcellulose or a composition of bentonite powder and sodium carboxymethylcellulose mixed in any proportion.

[0048] Specifically, the function of the slurry stabilizer is mainly to facilitate the formation of a stable and homogeneous slurry system for the iron tailings wet mud filling material, which does not segregate or delaminate during transportation and does not settle or bleed water after filling. Bentonite is a natural clay mineral with good expansibility and adsorbability. After contacting with water, the sodium ions in bentonite can exchange with the calcium ions in the slurry, causing the bentonite particles to expand and form a colloidal substance, increasing the mutual adhesion between slurry particles and the overall viscosity. Sodium carboxymethyl cellulose has the function of a water-retaining suspending agent. After contacting with water, it forms a colloidal film structure and adsorbs on the surface of tailings mud particles. The colloidal films aggregate and bridge with each other, "entrapping" the free water in the space of the colloidal film network, making the material form an integrated cohesive high-fluidity material, and it is not easy to show the situation of bleeding water and delamination.

[0049] As a preferred embodiment of the present invention, the setting and hardening regulator is any one of sodium silicate and sodium sulfate or a composition mixed in any proportion.

[0050] Specifically, setting and hardening agents such as sodium silicate and sodium sulfate are introduced into the tailings mud filling slurry, which increases the pH value of the slurry solution and reacts with the active SiO 2 , Al 2 O 3 components in slag powder and steel slag powder and the Ca(OH) 2 formed by quicklime powder to generate C-S-H gel, C-A-H gel and ettringite through synergistic action. These several hydration products together improve the strength of the fluid filling material.

[0051] As Figure 1 shown, the preparation method of the iron tailings mud-based high-fluidity filling material provided by the present invention as described above includes the following steps:

[0052] Step S1: Mix 8-15 parts of slag powder, 3-8 parts of steel slag powder, and 1-3 parts of quicklime powder evenly to obtain the gelling material powder A;

[0053] Step S2: Add 0.3-0.8 parts of dispersant, 1-2 parts of slurry stabilizer, and 0.5-1.0 parts of setting and hardening regulator to the gelling material powder A and mix evenly to obtain powder B;

[0054] Step S3: Stir 160-200 parts of iron tailings wet mud, and add the powder B during the stirring process, and stir until the preset time to obtain the iron tailings mud-based high-fluidity filling material.

[0055] As a preferred embodiment of the present invention, during the process of mixing 8-15 parts of slag powder, 3-8 parts of steel slag powder, and 1-3 parts of quicklime powder evenly to obtain the gelling material powder A,

[0056] Mix 8 - 15 parts of slag powder, 3 - 8 parts of steel slag powder, and 1 - 3 parts of quicklime powder evenly by mechanical stirring.

[0057] As a preferred embodiment of the present invention, during the process of stirring 160 - 200 parts of wet iron tailings mud and adding the powder B during the stirring process, stirring until a preset time to obtain the high-fluidity filling material based on iron tailings mud,

[0058] First, perform forced stirring on the wet iron tailings mud for 3 - 5 minutes, and then add the powder B;

[0059] The preset time is 8 - 10 minutes.

[0060] In order to better elaborate on the high-fluidity filling material based on iron tailings mud provided by the present invention and the technical effects achieved, specific examples are verified as follows:

[0061] Example 1

[0062] Prepare the following raw materials:

[0063] 165 parts by weight of wet iron tailings mud with a water content of 16%, 8 parts by weight of slag powder, 3 parts by weight of steel slag powder, 1.5 parts by weight of quicklime powder, 0.1 part by weight of sodium hexametaphosphate, 0.3 part by weight of polycarboxylate, 0.5 part by weight of bentonite, 0.1 part by weight of sodium carboxymethyl cellulose, 0.6 part by weight of sodium silicate, and 0.3 part by weight of sodium sulfate.

[0064] Mix 8 parts by weight of slag powder, 3 parts by weight of steel slag powder, and 1.5 parts by weight of quicklime powder evenly by mechanical mixing to obtain the mixed cementitious material A;

[0065] Then add 0.1 part by weight of sodium hexametaphosphate, 0.3 part by weight of polycarboxylate, 0.5 part by weight of bentonite, 0.1 part by weight of sodium carboxymethyl cellulose, 0.6 part by weight of sodium silicate, and 0.3 part by weight of sodium sulfate to the powder A and mix evenly to obtain the powder B;

[0066] Perform forced stirring on 165 parts by weight of wet iron tailings sand mud with a water content of 16% for 3 - 5 minutes, add the powder B and continue stirring for 8 - 10 minutes to obtain the high-fluidity filling material based on iron tailings mud. During construction operations, it is transported to the on-site filling construction after being evenly mixed at the mixing station.

[0067] Conduct performance tests on the prepared high-fluidity filling material, and the results are as follows: fluidity 320mm, initial setting time 2.5 hours, final setting time 4.5 hours, no delamination and no settlement after 24 hours of filling the mold, and 28-day compressive strength 5.79MPa.

[0068] Example 2

[0069] Prepare the following raw materials:

[0070] 160 parts by weight of iron tailings wet mud with a moisture content of 19%, 9.5 parts by weight of slag powder, 2.5 parts by weight of steel slag powder, 1.5 parts by weight of quicklime powder, 0.7 parts by weight of polycarboxylate, 0.8 parts by weight of bentonite, 0.15 parts by weight of sodium carboxymethyl cellulose, 0.4 parts by weight of sodium silicate, and 0.4 parts by weight of sodium sulfate.

[0071] Mix 8 parts by weight of slag powder, 3 parts by weight of steel slag powder, and 1.5 parts by weight of quicklime powder mechanically and evenly to obtain mixed cementitious material A;

[0072] Add 0.7 parts by weight of polycarboxylate, 0.8 parts by weight of bentonite, 0.15 parts by weight of sodium carboxymethyl cellulose, 0.4 parts by weight of sodium silicate, and 0.4 parts by weight of sodium sulfate to powder A and mix evenly to obtain powder B;

[0073] Forcefully stir 160 parts by weight of iron tailings sand wet mud with a moisture content of 19% for 3 - 5 minutes, add powder B and continue stirring for 8 - 10 minutes to obtain a high-fluidity filling material based on iron tailings mud. When carrying out construction operations, it is transported to the site for filling construction after being evenly mixed at the mixing station.

[0074] Conduct performance tests on the prepared high-fluidity filling material, and the results are as follows: fluidity 305mm, initial setting time 2 hours, final setting time 4.5 hours, no delamination and no settlement 24 hours after filling the mold, and 28-day compressive strength 6.13MPa.

[0075] Example 3

[0076] Prepare the following raw materials:

[0077] 170 parts by weight of iron tailings wet mud with a moisture content of 23%, 11 parts by weight of slag powder, 5 parts by weight of steel slag powder, 2 parts by weight of quicklime powder, 0.8 parts by weight of polycarboxylate, 0.3 parts by weight of bentonite, 0.3 parts by weight of sodium carboxymethyl cellulose, 0.8 parts by weight of sodium silicate, and 0.2 parts by weight of sodium sulfate.

[0078] Mix 11 parts by weight of slag powder, 5 parts by weight of steel slag powder, and 2 parts by weight of quicklime powder mechanically and evenly to obtain mixed cementitious material A;

[0079] Add 0.8 parts by weight of polycarboxylate, 0.3 parts by weight of bentonite, 0.3 parts by weight of sodium carboxymethyl cellulose, 0.8 parts by weight of sodium silicate, and 0.2 parts by weight of sodium sulfate to powder A and mix evenly to obtain powder B;

[0080] 170 parts by weight of iron tailings sand wet mud with a water content of 23% was forcibly stirred for 3 - 5 minutes, and after adding powder B, stirring was continued for 8 - 10 minutes to obtain a high-fluidity filling material based on iron tailings mud. During the construction operation, it was transported to the site for filling construction after being evenly mixed at the mixing station.

[0081] Performance tests were carried out on the prepared high-fluidity filling material, and the results were as follows: fluidity 330 mm, initial setting time 3 hours, final setting time 5 hours, no delamination and no settlement after 24 hours of filling the mold, and 28-day compressive strength 6.16 MPa.

[0082] Example 4

[0083] Prepare the following raw materials:

[0084] 175 parts by weight of iron tailings wet mud with a water content of about 20%, 13 parts by weight of slag powder, 4 parts by weight of steel slag powder, 1 part by weight of quicklime powder, 0.2 part by weight of sodium hexametaphosphate, 0.9 part by weight of polycarboxylate, 0.6 part by weight of bentonite, 0.4 part by weight of sodium carboxymethylcellulose, 0.9 part by weight of sodium silicate.

[0085] 13 parts of slag powder, 4 parts by weight of steel slag powder, and 1 part by weight of quicklime powder were mechanically mixed evenly to obtain a mixed cementitious material A;

[0086] 0.2 part by weight of sodium hexametaphosphate, 0.9 part by weight of polycarboxylate, 0.6 part by weight of bentonite, 0.4 part by weight of sodium carboxymethylcellulose, and 0.9 part by weight of sodium silicate were all added to powder A and mixed evenly to obtain powder B;

[0087] 175 parts by weight of iron tailings sand wet mud with a water content of 20% was forcibly stirred for 3 - 5 minutes, and after adding powder B, stirring was continued for 8 - 10 minutes to obtain a high-fluidity filling material based on iron tailings mud. During the construction operation, it was transported to the site for filling construction after being evenly mixed at the mixing station.

[0088] Performance tests were carried out on the prepared high-fluidity filling material, and the results were as follows: fluidity 330 mm, initial setting time 2.5 hours, final setting time 4 hours, no delamination and no settlement after 24 hours of filling the mold, and 28-day compressive strength 6.38 MPa.

[0089] Example 5

[0090] Prepare the following raw materials:

[0091] 180 parts by weight of iron tailings wet mud with a water content of 20%, 10 parts by weight of slag powder, 2.5 parts by weight of steel slag powder, 1.5 parts by weight of quicklime powder, 0.1 part by weight of sodium hexametaphosphate, 0.5 part by weight of polycarboxylate, 0.7 part by weight of bentonite, 0.2 part by weight of sodium carboxymethylcellulose, 0.7 part by weight of sodium silicate.

[0092] Mix 10 parts by weight of slag powder, 2.5 parts by weight of steel slag powder, and 1.5 parts by weight of quicklime powder mechanically and evenly to obtain mixed cementitious material A;

[0093] Add 0.1 part by weight of sodium hexametaphosphate, 0.5 part by weight of polycarboxylate, 0.7 part by weight of bentonite, 0.2 part by weight of sodium carboxymethyl cellulose, and 0.7 part by weight of sodium silicate to powder A and mix evenly to obtain powder B;

[0094] Take 180 parts by weight of wet iron tailings sand mud with a moisture content of 20%, conduct forced stirring for 3 - 5 minutes, add powder B and continue stirring for 8 - 10 minutes to obtain a high-fluidity filling material based on iron tailings mud. During construction operations, after mixing evenly at the mixing station, it is transported to the site for filling construction.

[0095] Conduct performance tests on the prepared high-fluidity filling material, and the results are as follows: fluidity 330mm, initial setting time 3 hours, final setting time 5 hours, no delamination and no settlement after 24 hours of filling the mold, and 28-day compressive strength 5.51MPa.

[0096] Example 6

[0097] Prepare the following raw materials:

[0098] 160 parts by weight of wet iron tailings mud with a moisture content of about 18%, 9 parts by weight of slag powder, 3 parts by weight of steel slag powder, 2 parts by weight of quicklime powder, 0.15 part by weight of sodium hexametaphosphate, 0.6 part by weight of polycarboxylate, 0.8 part by weight of bentonite, 0.1 part by weight of sodium carboxymethyl cellulose, and 0.8 part by weight of sodium silicate.

[0099] Mix 9 parts by weight of slag powder, 3 parts by weight of steel slag powder, and 2 parts by weight of quicklime powder mechanically and evenly to obtain mixed cementitious material A;

[0100] Add 0.15 part by weight of sodium hexametaphosphate, 0.6 part by weight of polycarboxylate, 0.8 part by weight of bentonite, 0.1 part by weight of sodium carboxymethyl cellulose, and 0.8 part by weight of sodium silicate to powder A and mix evenly to obtain powder B;

[0101] Take 160 parts by weight of wet iron tailings sand mud with a moisture content of 20%, conduct forced stirring for 3 - 5 minutes, add powder B and continue stirring for 8 - 10 minutes to obtain a high-fluidity filling material based on iron tailings mud. During construction operations, after mixing evenly at the mixing station, it is transported to the site for filling construction.

[0102] Conduct performance tests on the prepared high-fluidity filling material, and the results are as follows: fluidity 315mm, initial setting time 2 hours, final setting time 4 hours, no delamination and no settlement after 24 hours of filling the mold, and 28-day compressive strength 5.13MPa.

[0103] After construction application, it is found that the high-fluidity filling material based on iron tailings mud has good fluidity and can well fill the required positions for backfilling. The strength of the casting body is appropriate and the integrity is stable, which fully meets the performance requirements of engineering applications.

[0104] It should be noted that the above specific implementation manners are only for the verification of the effects of the iron tailings mud-based high-fluidity filling material provided by the present invention in the actual experimental process, and do not limit the technical solutions provided by the present invention.

[0105] It can be seen from the above specific implementation manners that for the iron tailings mud-based high-fluidity filling material and its preparation method provided by the present invention, the wet iron tailings mud is used as the main material of the high-fluidity filling material. The high-moisture-content tailings mud does not need to be dehydrated and stored, which greatly saves the dehydration cost and effectively solves the problems of difficult storage and environmental pollution caused by the stacking of a large amount of iron tailings. The solid waste powders such as slag powder, steel slag powder, and quicklime powder are used as the cementitious material components of the filling material, replacing the use of high-consumption materials such as cement clinker, realizing the high-value utilization of solid waste resources. And under the synergistic action of the solid waste powder as the cementitious material component with the dispersant, slurry stabilizer, and setting and hardening regulator, the prepared high-fluidity filling material has the advantages of uniform texture mixing, excellent fluidity, can achieve swelling self-leveling paving filling, no bleeding and no settlement after filling, and no shrinkage after setting and hardening. It can be used for the filling construction of various foundation pits and mine pits, thus realizing the large-scale resource utilization of a large amount of waste resources, and having good social and economic benefits and resource and environmental benefits.

[0106] As described above by way of example with reference to the drawings, the iron tailings mud-based high-fluidity filling material and its preparation method proposed according to the present invention are described. However, those skilled in the art should understand that various improvements can be made to the above iron tailings mud-based high-fluidity filling material and its preparation method without departing from the content of the present invention. Therefore, the protection scope of the present invention should be determined by the content of the appended claims.

Claims

1. An iron tailings mud-based high-fluidity filling material, characterized in that: The invention comprises the following raw materials in parts by weight: 160-200 parts of iron tailings wet mud, 8-15 parts of slag powder, 3-8 parts of steel slag powder, 1-3 parts of quicklime powder, 0.3-0.8 parts of dispersant, 1-2 parts of slurry stabilizer, and 0.5-1.0 parts of coagulation and hardening regulator.

2. The iron tailings mud-based high-fluidity filling material according to claim 1, characterized in that: The water content of the iron tailings wet mud is 15% to 30%.

3. The iron tailings mud-based high-fluidity filling material according to claim 1, characterized in that: The weight of the iron tailings wet mud accounts for more than 80% of the weight of the iron tailings mud-based high-fluidity filling material.

4. The iron tailings mud-based high-fluidity filling material according to claim 1, characterized in that: The particle size of the iron tailings wet mud is less than 100 μm, and the specific surface area is greater than 600 m 2 / kg.

5. The iron tailings mud-based high-fluidity filling material according to claim 1, characterized in that: The dispersant is sodium hexametaphosphate or polycarboxylate water reducer or a combination of sodium hexametaphosphate and polycarboxylate water reducer mixed in any proportion.

6. The iron tailings mud-based high-fluidity filling material according to claim 1, characterized in that: The slurry stabilizer is bentonite powder or sodium carboxymethyl cellulose or a combination of bentonite powder and sodium carboxymethyl cellulose mixed in any proportion.

7. The iron tailings mud-based high-fluidity filling material according to claim 1, characterized in that: The coagulation and hardening regulator is any one of sodium silicate and sodium sulfate, or a combination thereof mixed in any proportion.

8. A method for preparing the iron tailings mud-based high-fluidity filling material according to any one of claims 1 to 7, characterized in that: The steps include: 8 to 15 parts of slag powder, 3 to 8 parts of steel slag powder, and 1 to 3 parts of quicklime powder are uniformly mixed to obtain cementitious material powder A; Add 0.3-0.8 parts of a dispersant, 1-2 parts of a slurry stabilizer, and 0.5-1.0 parts of a coagulation and hardening regulator to the cementitious material powder A, and mix them evenly to obtain a powder B; 160 to 200 parts of wet iron tailings mud are stirred, and the powder B is added during the stirring process, and stirred for a preset time to obtain an iron tailings mud-based high-fluidity filling material.

9. The method for preparing the iron tailings mud-based high-fluidity filling material according to claim 8, characterized in that: In the process of uniformly mixing 8 to 15 parts of slag powder, 3 to 8 parts of steel slag powder, and 1 to 3 parts of quicklime powder to obtain cementitious material powder A, 8 to 15 parts of slag powder, 3 to 8 parts of steel slag powder and 1 to 3 parts of quicklime powder are mixed evenly by mechanical stirring.

10. The method for preparing the iron tailings mud-based high-fluidity filling material according to claim 8, characterized in that: In the process of stirring 160 to 200 parts of wet iron tailings mud, adding the powder B during the stirring process, and stirring for a preset time to obtain an iron tailings mud-based high-fluidity filling material, Firstly, the iron tailings wet mud is forcibly stirred for 3 to 5 minutes, and then the powder B is added; The preset time is 8 to 10 minutes.

Images