Mine filling cementing material, preparation method thereof and mine filling material
By combining high-sulfur iron tailings with alkali activators, S95 mineral powder, composite complexing agents, and crystal form regulators, the problems of slow early strength development and poor volume stability of high-sulfur iron tailings in the cementing system were solved, realizing the preparation of efficient and economical cementing materials to meet the engineering needs of mine backfilling.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI MAGANG LUOHE MINING CO LTD
- Filing Date
- 2025-12-31
- Publication Date
- 2026-05-12
AI Technical Summary
High-sulfur iron tailings are prone to slow early strength development and poor volume stability in cementation systems, and traditional filling cementitious materials are costly.
By using a combination of high-sulfur iron tailings, alkali activator, S95 mineral powder, composite complexing agent and crystal form regulator, a controllable cementitious network is formed through complexing ions and regulating the formation morphology of ettringite, thereby achieving a balance between strength development and volume stability.
It enables the safe and efficient utilization of high-sulfur tailings, increases the admixture content by more than 40%, reduces costs, and has excellent early strength and long-term stability, meeting the engineering requirements for mine backfilling.
Smart Images
Figure CN122010437A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of building materials technology, specifically relating to a mine filling cementitious material, its preparation method, and the mine filling material. Background Technology
[0002] Iron tailings are a large amount of solid waste generated during iron ore beneficiation. Some iron ore deposits contain abundant sulfate minerals, resulting in sulfur in the tailings primarily occurring as gypsum (anhydrite, hemihydrate gypsum, and dihydrate gypsum), with SO3 content reaching 18%–25%, while the content of sulfides such as pyrite (FeS2) is relatively low. The large-scale and safe utilization of such high-sulfur iron tailings is one of the key challenges in the field of mine solid waste resource utilization.
[0003] When using high-sulfur iron tailings with high admixture levels, the gypsum contained therein will dissolve rapidly in the early stages of hydration in the cementation system, releasing a high concentration of SO4²⁻. - These sulfate ions react rapidly with active components such as tricalcium aluminate (C3A) in the cementitious material, generating a large amount of ettringite (AFt). This rapid and concentrated ettringite formation, directly triggered by internal sulfates, poses a dual challenge to material performance: First, the large-scale early formation of ettringite not only consumes key aluminum sources in the system but also hinders the further dissolution of silicon and aluminum sources, interfering with the normal formation and development of CSH gel, resulting in slow early strength development of the material; Second, the uncontrolled timing and spatial distribution of ettringite formation makes its crystallization pressure prone to causing internal damage before the slurry microstructure is sufficiently strengthened, and continuously triggering unfavorable expansion in the later stages, ultimately manifesting as stagnation or even decline in the 28-day activity index growth of the material, as well as a reduction in long-term compressive strength. In the field of cemented backfilling, this directly relates to the early support capacity and long-term stability and safety of goaf backfill bodies.
[0004] Therefore, there is an urgent need to provide a cementitious material that can regulate the kinetics of gypsum dissolution and ettringite formation, thereby achieving a balance between strength development and volume stability. Summary of the Invention
[0005] To address the technical problems in existing technologies where the use of high-sulfur iron tailings with high admixture content easily leads to slow strength development and poor volume stability of cementitious materials, as well as the high cost of traditional backfill cementitious materials, this invention provides a mine backfill cementitious material, its preparation method, and mine backfill material. This cementitious material can be used to replace cement and cementitious powder in backfill materials, reducing cement usage and lowering costs. The backfill material prepared by this material meets the requirements in terms of strength, fluidity, and durability.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: A mine filling cementitious material, by weight, comprises the following raw material components: 20-60 parts of high-sulfur iron tailings powder, 5-20 parts of alkali activator, 30-60 parts of S95 mineral powder, 0.01-1.0 parts of composite complexing agent, and 1-5 parts of crystal form regulator.
[0007] Furthermore, the high-sulfur iron tailings powder contains 18%–25% SO3, 15%–23% Fe2O3, 20%–30% SiO2, 3%–10% Al2O3, and has a specific surface area of 300–500 m². 2 / kg.
[0008] Furthermore, the alkali activator is selected from one or more combinations of clinker, carbide slag, and red mud; And / or, the crystal form modifier is selected from one or more combinations of nano-silicon, calcium formate, and acrylic acid.
[0009] Furthermore, the S95 mineral powder has an Al2O3 content of ≥13% and a specific surface area of ≥400m². 2 / kg, with an activity index of 95%–105% after 28 days.
[0010] Furthermore, the composite complexing agent is a mixture of triethanolamine and triisopropanolamine, wherein the mass ratio of triethanolamine to triisopropanolamine is (1-20):(3-18), and the mass ratio of the composite complexing agent to the total SO3 in the gelling system is (0.005-1):1.
[0011] Furthermore, it also includes a polycarboxylate high-performance water-reducing agent, wherein the polycarboxylate high-performance water-reducing agent has a mass fraction of 0.2 parts.
[0012] In addition, the present invention also provides a method for preparing the mine backfill cementitious material as described above, comprising the following steps: S1. Dry the high-sulfur iron tailings to a moisture content of ≤1.0%, and then grind them to obtain high-sulfur iron tailings powder; S2. Weigh out the high-sulfur iron tailings powder, alkali activator, S95 mineral powder, composite complexing agent, and crystal form regulator according to the formula and mix them evenly to obtain the mine filling cementitious material.
[0013] Further, in step S1, the drying temperature is 60℃; the grinding process is carried out by mechanical grinding using an experimental mill with a capacity of 5kg, a ball-to-material ratio of (3~5):1, and a rotation speed of 40~55r / min.
[0014] Further, in step S2, the mixing is carried out using a mixer, and the mixing conditions are to use a homogenizer to stir at 40~60 r / min for 10~20 min.
[0015] In addition, the present invention also provides a mine backfill material, comprising the aforementioned mine backfill cementitious material, water and wet-based iron tailings, wherein the mass ratio of the three is 1:(3~8):(3~10); the moisture content of the wet-based iron tailings is 20%.
[0016] Compared with the prior art, the technical solution of the present invention has at least the following technical effects: (1) This invention achieves safe and efficient utilization of anhydrite-type high-sulfur tailings through system compatibility and reaction control, increasing the amount of high-sulfur tailings by more than 40%, and providing a reliable technical path for the large-scale disposal of similar tailings.
[0017] (2) This invention achieves active regulation of the dissolution of anhydrite and the subsequent formation of ettringite by introducing a composite complexing agent and a crystal form regulator. The composite complexing agent complexes Ca... 2+ Al 3+ and Fe 3+ Ions effectively delayed the early dissolution of anhydrite, coordinating the sulfate release rate with the formation process of the cementitious network. Crystal form regulators, through interfacial adsorption, guided the growth of ettringite crystals towards a shorter columnar morphology with lower expansion stress. The synergistic effect of these two agents transformed anhydrite from a "harmful source of expansion" into a "controllable reinforcing phase," achieving a balance between strength development and volume stability. This provides a novel regulatory approach and method for the utilization of high-sulfate solid waste.
[0018] (3) The solid waste raw materials in the cementitious material of this invention can account for more than 90%, which has good economic benefits and greatly reduces carbon emissions. In addition, the filling material prepared by the cementitious material has good compatibility with wet tailings, low bleeding rate, excellent early strength and long-term stability, and meets the engineering requirements of high-strength safe filling in mines. Attached Figure Description
[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein: Figure 1 This is an XRD pattern of high-sulfur iron tailings used in this invention. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions.
[0021] The endpoints and any values of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.
[0022] According to a first aspect of the present invention, a mine filling cementitious material is provided, comprising the following raw material components by weight: 20-60 parts of high-sulfur iron tailings powder, 5-20 parts of alkali activator, 30-60 parts of S95 mineral powder, 0.01-1.0 parts of composite complexing agent and 1-5 parts of crystal form regulator.
[0023] The core design logic of the technical solution of this invention is as follows: The high-sulfur iron tailings powder used in this invention primarily serves as a sulfate source. Under the action of an alkaline activator, a dual sulfate-alkali activation is achieved. However, excessive tailings content can lead to sulfate overload in the system, potentially causing harmful expansion. Therefore, this invention introduces a dual regulation mechanism using a composite complexing agent and a crystal form regulator. The composite complexing agent selectively complexes calcium, aluminum, and iron ions in the solution to form soluble complexes. This effectively buffers the dissolution rate of anhydrite and the instantaneous concentration of ions in the solution, delaying the rapid growth of ettringite in the early stages of hydration. Furthermore, as hydration progresses, the soluble complexes dispersed in various locations desorb, with iron ions incorporating into the ettringite to form iron-containing ettringite, thus delaying its formation. Simultaneously, the crystal form regulator adsorbs onto specific growth surfaces of the ettringite crystals, altering their surface energy and guiding the crystals towards a shorter columnar morphology with less expansion stress. Under controlled reaction rates and guided crystal morphology, ettringite, generated through a pozzolanic reaction with S95 mineral powder, interweaves with a large amount of C-(A)-SH gel to form a three-dimensional network framework, achieving long-term stability of the cementitious system. The proportions of each raw material component are optimized to ensure that the hydration products are controllable in both space and quantity, achieving a balance between strength development and volume stability. Furthermore, the addition of a high-performance polycarboxylate superplasticizer improves the material's fluidity, adapting it to the needs of mine backfilling construction.
[0024] Based on the above scheme, as a preferred embodiment, the high-sulfur iron tailings powder contains 18%–25% SO3, 15%–23% Fe2O3, 20%–30% SiO2, 3%–10% Al2O3, and has a specific surface area of 300–500 m². 2 / kg. The alkali activator is selected from one or more combinations of clinker, carbide slag, and red mud; the crystal form regulator is selected from one or more combinations of nano-silicon, calcium formate, and acrylic acid, preferably nano-silicon. The S95 mineral powder has an Al2O3 content ≥13% and a specific surface area ≥400m². 2 / kg, with an activity index of 95%–105% after 28 days. The composite complexing agent is a mixture of triethanolamine and triisopropanolamine, with a mass ratio of (1–20):(3–18) for triethanolamine and (0.005–1):1 for the total SO3 in the gelling system. (The proportion of the composite complexing agent is adjusted according to the different complexing abilities of triethanolamine and triisopropanolamine for metal ions (calcium, iron, and aluminum).)
[0025] Based on the above scheme, as a preferred embodiment, the raw materials of the mine filling cementitious material of the present invention also include polycarboxylate high-performance water-reducing agent, wherein the mass fraction of the polycarboxylate high-performance water-reducing agent is 0.2 parts.
[0026] According to a second aspect of the present invention, a method for preparing the mine backfill cementitious material as described above is provided, comprising the following steps: (1) Dry the high-sulfur iron tailings at 60℃ until the moisture content is ≤1.0%, and then mechanically grind them using a 5kg experimental mill, controlling the ball-to-material ratio at (3~5):1 and the rotation speed at 40~55r / min, until the specific surface area is 300~500m². 2 / kg, to obtain high-sulfur iron tailings powder; (2) Weigh out the high-sulfur iron tailings powder, alkali activator, S95 mineral powder, composite complexing agent and crystal form regulator according to the proportion, and mix them in a mixer until the material is uniform to obtain a high-sulfur iron tailings content mine filling cementitious material.
[0027] According to a third aspect of the present invention, a mine backfill material is provided, comprising the aforementioned mine backfill cementitious material, water, and wet-based iron tailings, wherein the mass ratio of the three is 1:(3~8):(3~10); the moisture content of the wet-based iron tailings is 20%.
[0028] During preparation, weigh the mine filling cementitious material, water and wet-based iron tailings in a mass ratio of 1:(3~8):(3~10), pour the three into a mixer and stir evenly to obtain the mine filling material; put the filling material into a mold or directly fill it into the mine goaf area, and cure it under standard curing conditions (temperature 20±1℃, humidity ≥95%) to obtain the filling body.
[0029] The present invention will now be described in detail with reference to embodiments thereof. These examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present invention without departing from its scope or spirit. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present invention encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.
[0030] In the embodiments of the present invention, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.
[0031] Example 1 This invention provides a method for preparing a mine backfill cementitious material with high sulfur and iron tailings content: (1) Dry the high-sulfur iron tailings for 24 hours in advance, with the drying temperature set at 60℃, to obtain high-sulfur iron tailings with a moisture content of ≤1.0%, and set them aside for later use; (2) The dried, lumpy high-sulfur iron tailings were placed in an experimental grinder and crushed for 1 minute to obtain a specific surface area of 385 m². 2 / kg of high-sulfur iron tailings powder, for later use; (3) Weigh 40 parts of high-sulfur iron tailings powder, 20 parts of cement clinker, 40 parts of S95 mineral powder, and 0.2 parts of polycarboxylate high-performance water-reducing agent according to the mass fraction. The total SO3 content is 10.67%. Based on the SO3 content, take 0.2 parts of composite complexing agent (triethanolamine: triisopropanolamine = 1:3) and 2 parts of crystal form regulator. Then, mix the high-sulfur iron tailings powder, cement clinker, S95 mineral powder, polycarboxylate high-performance water-reducing agent, composite complexing agent and crystal form regulator evenly and prepare standard mortar according to GBT 17671-2021.
[0032] (4) The mortar prepared above is evenly loaded into the mold and cured in a standard curing box. After 1 day, it is demolded and cured under standard curing conditions for 3 days, 7 days and 28 days. Then the compressive strength is tested at 3 days, 7 days and 28 days.
[0033] Example 2 This invention provides a method for preparing a mine backfill cementitious material with high sulfur and iron tailings content: (1) Dry the high-sulfur iron tailings for 24 hours in advance, with the drying temperature set at 60℃, to obtain high-sulfur iron tailings with a moisture content of ≤1.0%, and set them aside for later use; (2) The dried, lumpy high-sulfur iron tailings were placed in an experimental grinder and crushed for 1 minute to obtain a specific surface area of 385 m². 2 / kg of high-sulfur iron tailings powder, for later use; (3) Weigh 40 parts of high-sulfur iron tailings powder, 20 parts of cement clinker, 5 parts of desulfurized gypsum, 35 parts of S95 mineral powder, and 0.2 parts of polycarboxylate high-performance water-reducing agent according to the mass fraction. The total SO3 content is 12.93%. Based on the SO3 content, take 0.2 parts of composite complexing agent (triethanolamine: triisopropanolamine = 5:3) and 2 parts of crystal form regulator. Then, mix the high-sulfur iron tailings powder, cement clinker, S95 mineral powder, polycarboxylate high-performance water-reducing agent, composite complexing agent and crystal form regulator evenly and prepare standard mortar according to GBT 17671-2021.
[0034] (4) The mortar prepared above is evenly loaded into the mold and cured in a standard curing box. After 1 day, it is demolded and cured under standard curing conditions for 3 days, 7 days and 28 days. Then the compressive strength is tested at 3 days, 7 days and 28 days.
[0035] Comparative Example 1 This invention provides a method for preparing a mine backfill cementitious material with high sulfur and iron tailings content: (1) Dry the high-sulfur iron tailings for 24 hours in advance, with the drying temperature set at 60℃, to obtain high-sulfur iron tailings with a moisture content of ≤1.0%, and set them aside for later use; (2) The dried, lumpy high-sulfur iron tailings were placed in an experimental grinder and crushed for 1 minute to obtain a specific surface area of 385 m². 2 / kg of high-sulfur iron tailings powder, for later use; (3) Weigh 40 parts of high-sulfur iron tailings powder, 20 parts of cement clinker, and 40 parts of S95 mineral powder according to the mass fraction. The total SO3 content is 10.67%. Then, mix the high-sulfur iron tailings powder, cement clinker, and S95 mineral powder evenly and prepare standard mortar according to GBT 17671-2021.
[0036] (4) The mortar prepared above is evenly loaded into the mold and cured in a standard curing box. After 1 day, it is demolded and cured under standard curing conditions for 3 days, 7 days and 28 days. Then the compressive strength is tested at 3 days, 7 days and 28 days.
[0037] Comparative Example 2 This invention provides a method for preparing a mine backfill cementitious material with high sulfur and iron tailings content: (1) Dry the high-sulfur iron tailings for 24 hours in advance, with the drying temperature set at 60℃, to obtain high-sulfur iron tailings with a moisture content of ≤1.0%, and set them aside for later use; (2) The dried, lumpy high-sulfur iron tailings were placed in an experimental grinder and crushed for 1 minute to obtain a specific surface area of 385 m². 2 / kg of high-sulfur iron tailings powder, for later use; (3) Weigh 40 parts of high-sulfur iron tailings powder, 20 parts of cement clinker, and 40 parts of S95 mineral powder according to the mass fraction. The total SO3 content is 10.67%. Take 0.2 parts of composite complexing agent (triethanolamine: triisopropanolamine = 1:3) according to the SO3 content. Then mix the high-sulfur iron tailings powder, cement clinker, S95 mineral powder and composite complexing agent evenly and prepare standard mortar according to GBT 17671-2021.
[0038] (4) The mortar prepared above is evenly loaded into the mold and cured in a standard curing box. After 1 day, it is demolded and cured under standard curing conditions for 3 days, 7 days and 28 days. Then the compressive strength is tested at 3 days, 7 days and 28 days.
[0039] Comparative Example 3 This invention provides a method for preparing a mine backfill cementitious material with high sulfur and iron tailings content: (1) Dry the high-sulfur iron tailings for 24 hours in advance, with the drying temperature set at 60℃, to obtain high-sulfur iron tailings with a moisture content of ≤1.0%, and set them aside for later use; (2) The dried, lumpy high-sulfur iron tailings were placed in an experimental grinder and crushed for 1 minute to obtain a specific surface area of 385 m². 2 / kg of high-sulfur iron tailings powder, for later use; (3) Weigh 40 parts of high-sulfur iron tailings powder, 20 parts of cement clinker, 5 parts of desulfurized gypsum and 35 parts of S95 mineral powder according to the mass fraction. The total SO3 content is 12.93%. Then mix the high-sulfur iron tailings powder, desulfurized gypsum, cement clinker and S95 mineral powder evenly and prepare standard mortar according to GBT 17671-2021.
[0040] (4) The mortar prepared above is evenly loaded into the mold and cured in a standard curing box. After 1 day, it is demolded and cured under standard curing conditions for 3 days, 7 days and 28 days. Then the compressive strength is tested at 3 days, 7 days and 28 days.
[0041] Comparative Example 4 This invention provides a method for preparing a mine backfill cementitious material with high sulfur and iron tailings content: (1) Dry the high-sulfur iron tailings for 24 hours in advance, with the drying temperature set at 60℃, to obtain high-sulfur iron tailings with a moisture content of ≤1.0%, and set them aside for later use; (2) The dried, lumpy high-sulfur iron tailings were placed in an experimental grinder and crushed for 1 minute to obtain a specific surface area of 385 m². 2 / kg of high-sulfur iron tailings powder, for later use; (3) Weigh 40 parts of high-sulfur iron tailings powder, 20 parts of cement clinker, 5 parts of desulfurized gypsum and 35 parts of S95 mineral powder according to the mass fraction. The total SO3 content is 12.93%. Take 0.2 parts of composite complexing agent (triethanolamine: triisopropanolamine = 5:3) according to the SO3 content. Then mix the high-sulfur iron tailings powder, cement clinker, S95 mineral powder and composite complexing agent evenly and prepare standard mortar according to GBT 17671-2021.
[0042] (4) The mortar prepared above is evenly loaded into the mold and cured in a standard curing box. After 1 day, it is demolded and cured under standard curing conditions for 3 days, 7 days and 28 days. Then the compressive strength is tested at 3 days, 7 days and 28 days.
[0043] Comparative Example 5 Standard mortar was prepared using commercially available cementitious powder (provided by Maanshan Iron & Steel Co., Ltd.) as the cementing material.
[0044] Example 3 This invention provides a filling material, using the cementing material prepared in Example 1. The preparation steps of the filling material are as follows: (1) Weigh out 400 parts of cementitious material and 2400 parts of wet-based iron tailings according to the mass fraction, and set aside for later use; (2) Pour the weighed material into a mixer and mix evenly to obtain the filling material; (3) The well-stirred filling material is put into the mold and cured under standard curing conditions to obtain the filling body test block.
[0045] Example 4 This invention provides a filling material, using the cementing material prepared in Example 2. The preparation steps of the filling material are as follows: (1) Weigh out 400 parts of cementitious material and 2400 parts of wet-based iron tailings according to the mass fraction, and set aside for later use; (2) Pour the weighed material into a mixer and mix evenly to obtain the filling material; (3) The well-stirred filling material is put into the mold and cured under standard curing conditions to obtain the filling body test block.
[0046] Comparative Example 6 This invention provides a filling material, using the same cementing material prepared in Comparative Example 1. The preparation steps of the filling material are as follows: (1) Weigh out 400 parts of cementitious material and 2400 parts of wet-based iron tailings according to the mass fraction, and set aside for later use; (2) Pour the weighed material into a mixer and mix evenly to obtain the filling material; (3) The well-stirred filling material is put into the mold and cured under standard curing conditions to obtain the filling body test block.
[0047] Comparative Example 7 This invention provides a filling material, using the same cementing material prepared in Comparative Example 2. The preparation steps of the filling material are as follows: (1) Weigh out 400 parts of cementitious material and 2400 parts of wet-based iron tailings according to the mass fraction, and set aside for later use; (2) Pour the weighed material into a mixer and mix evenly to obtain the filling material; (3) The well-stirred filling material is put into the mold and cured under standard curing conditions to obtain the filling body test block.
[0048] Comparative Example 8 This invention provides a filling material, using the same cementing material prepared in Comparative Example 3. The preparation steps of the filling material are as follows: (1) Weigh out 400 parts of cementitious material and 2400 parts of wet-based iron tailings according to the mass fraction, and set aside for later use; (2) Pour the weighed material into a mixer and mix evenly to obtain the filling material; (3) The well-stirred filling material is put into the mold and cured under standard curing conditions to obtain the filling body test block.
[0049] Comparative Example 9 This invention provides a filling material, using the same cementing material prepared in Comparative Example 4. The preparation steps of the filling material are as follows: (1) Weigh out 400 parts of cementitious material and 2400 parts of wet-based iron tailings according to the mass fraction, and set aside for later use; (2) Pour the weighed material into a mixer and mix evenly to obtain the filling material; (3) The well-stirred filling material is put into the mold and cured under standard curing conditions to obtain the filling body test block.
[0050] Comparative Example 10 Commercially available cementitious powder (provided by Maanshan Iron & Steel Co., Ltd.) was used as a cementing material to prepare the filler.
[0051] Test Example To evaluate the long-term volume stability and mechanical properties of the cementitious material of this invention, linear expansion rate and mechanical tests were conducted on representative examples and comparative examples, referring to the Cement Mortar Strength Test Method (GBT 17671-2021) and the Expansion Rate Test Method for Expansive Cement (JC / T 313-2009). The results are shown in Tables 1 and 2 below.
[0052] Table 1. Test results of mechanical properties and linear expansion rate of cementitious materials Table 2 Performance test results of filling materials The data in Tables 1 and 2 show that the technical solution of the present invention effectively solves the contradiction between the strength and volume stability of high-sulfur iron tailings cementitious materials. In Example 1, after adding the crystal form regulator, the strength at each age was improved compared with Comparative Example 2, and the expansion rate decreased, verifying its positive effect on optimizing the morphology of expansion products. When the total SO3 content in the cementing system increased from 10.67% to 12.93%, compared with Examples 1 and 2, the 28-day strength of Comparative Examples 1, 2, 3, and 4 decreased by 18%, 3%, 80%, and 14%, respectively, and the 28-day expansion rate decreased by 74%, 27%, 77%, and 48%, respectively, highlighting the synergistic effect of the composite complexing agent and the crystal form regulator in regulating the hydration balance of the high-sulfur system. When used as a filling cementitious material, the 28-day strength (1.8-3.5 MPa) of the material fully meets the mine backfill strength standard (>1 MPa) and is superior to that of cementitious powder. In summary, the cementitious material prepared by this invention provides a high-value-added resource utilization approach for bulk high-sulfur iron tailings, significantly reducing backfilling costs and carbon emissions.
[0053] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any technical solutions obtained by means of equivalent substitution or equivalent transformation should be covered within the protection scope of the present invention.
Claims
1. A mine filling cementitious material, characterized in that, By weight, it includes the following raw material components: 20-60 parts of high-sulfur iron tailings powder, 5-20 parts of alkali activator, 30-60 parts of S95 ore powder, 0.01-1.0 parts of composite complexing agent and 1-5 parts of crystal form regulator.
2. The mine backfill cementitious material according to claim 1, characterized in that, The high-sulfur iron tailings powder contains 18%–25% SO3, 15%–23% Fe2O3, 20%–30% SiO2, and 3%–10% Al2O3, with a specific surface area of 300–500 m². 2 / kg.
3. The mine backfill cementitious material according to claim 1, characterized in that, The alkali activator is selected from one or more combinations of clinker, carbide slag and red mud; And / or, the crystal form modifier is selected from one or more combinations of nano-silicon, calcium formate, and acrylic acid.
4. The mine backfill cementitious material according to claim 1, characterized in that, The S95 mineral powder contains ≥13% Al2O3 and has a specific surface area ≥400 m². 2 / kg, with an activity index of 95%–105% after 28 days.
5. The mine backfill cementitious material according to claim 1, characterized in that, The composite complexing agent is a mixture of triethanolamine and triisopropanolamine, wherein the mass ratio of triethanolamine to triisopropanolamine is (1-20):(3-18), and the mass ratio of the composite complexing agent to the total SO3 in the gelling system is (0.005-1):
1.
6. The mine backfill cementitious material according to claim 1, characterized in that, It also includes a polycarboxylate high-performance water-reducing agent, wherein the polycarboxylate high-performance water-reducing agent has a mass fraction of 0.2 parts.
7. A method for preparing a mine backfill cementitious material as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Dry the high-sulfur iron tailings to a moisture content of ≤1.0%, and then grind them to obtain high-sulfur iron tailings powder; S2. Weigh out the high-sulfur iron tailings powder, alkali activator, S95 mineral powder, composite complexing agent, and crystal form regulator according to the formula and mix them evenly to obtain the mine filling cementitious material.
8. The preparation method according to claim 7, characterized in that, In step S1, the drying temperature is 60℃; the grinding process is carried out by mechanical grinding using an experimental mill with a capacity of 5kg, a ball-to-material ratio of (3~5):1, and a rotation speed of 40~55r / min.
9. The preparation method according to claim 7, characterized in that, In step S2, the mixing is carried out using a mixer, and the mixing conditions are: using a homogenizer to mix at 40~60 r / min for 10~20 min.
10. A type of mine backfill material, characterized in that, The material includes the mine backfill cementitious material as described in any one of claims 1-6, water, and wet-based iron tailings, wherein the mass ratio of the three is 1:(3~8):(3~10); and the water content of the wet-based iron tailings is 20%.