Mine filling cementing material based on copper carbide slag and application of mine filling cementing material

Abstract

The invention discloses a mine filling cementing material based on carbonized copper slag and application thereof, and belongs to the technical field of industrial solid waste resource utilization, the mine filling cementing material comprises the following raw materials by mass: 65-75% of carbonized copper slag, 20-30% of an auxiliary cementing material and 3-8% of a composite activator. The invention also discloses an application of the filling material in mine filling. The copper slag is further ground to release a vitreous body structure in the copper slag, the activity of the copper slag is effectively improved, meanwhile, dissolution of iron and an active silicon-aluminum phase can be promoted, and the activity of the copper slag is effectively activated.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of industrial solid waste resource utilization, and particularly relates to a mine filling cementing material based on carbonized copper slag and application thereof. BACKGROUND

[0002] Copper slag is a waste slag produced during copper smelting, and its emission amount is about 2-3 times of the production of metal copper. Copper slag has the characteristics of fine particle size, multiple types, complex composition, etc., and has a low resource utilization rate. Basically, it is stored in the form of stacking, and the cumulative amount has reached hundreds of millions of tons. Long-term disposal of copper slag occupies land and causes serious impact on water quality and the environment. It is imperative to develop high-efficiency resource utilization of copper slag.

[0003] To solve the problem of stacking of copper smelting slag, new cementing materials are currently prepared from metallurgical slag and applied to mine cementation filling. The use of cementing materials in mine filling materials is one of the important factors affecting the performance of cementation filling body and is also the key to controlling the cost of filling materials. Because of the wide source of raw materials and relatively stable performance, cement has become the most commonly used cementing material. However, the cost of cement accounts for about 60% to 80% of the cost of cementation filling materials, and the carbon emission during cement production is high. Using copper slag as a secondary resource to prepare new cementing materials for mine filling not only realizes resource recycling and reduces filling cost, but also reduces secondary environmental pollution caused by copper tailings. However, the glass content in copper slag is low, the iron content is too high, the calcium content is too low, and the hydration activity is very low, which greatly limits its application in new cementing materials.

[0004] In the prior art, mechanical activation, chemical activation, and direct carbonization method are mainly used to modify copper slag. Among them, mechanical activation such as superfine grinding has high energy consumption; chemical activation such as alkali activation has corrosion and stability problems; and direct carbonization method has limited modification effect on copper slag, and it is difficult to balance the activity improvement and CO2 sequestration.

[0005] Therefore, how to provide a method for activating copper slag is a technical problem that those skilled in the art need to solve. SUMMARY

[0006] To solve the above technical problems, the present application provides a mine filling cementing material based on carbonized copper slag and application thereof.

[0007] To achieve the above purpose, the present application provides the following technical solutions: A mine filling cementing material based on carbonized copper slag, comprising the following raw materials in mass fraction: carbonized copper slag 65-75%, auxiliary cementing material 20-30%, and composite activator 3-8%.

[0008] Beneficial Effects: This formulation range represents an optimal balance point selected through extensive experimentation. Copper carbide slag, as the core active component, constitutes 65-75% to ensure that its early hydration products and microskeleton structure dominate material performance. Below this range, activity is insufficient; above it, system viscosity increases and fluidity deteriorates. Auxiliary cementitious materials comprise 20-30% to supplement aluminosilicate sources, adjust system composition, and promote stable strength development in the later stages. The composite activator comprises 3-8%, which, within this range, provides sufficient chemical activation, significantly enhancing cementitious activity, while avoiding excessive addition that could lead to slurry segregation or a surge in costs. Furthermore, the synergistic effect of these three components achieves an optimal combination of activity, workability, and economy.

[0009] Preferably, the auxiliary cementing material is slag and / or fly ash.

[0010] Beneficial effects: Slag is rich in CaO and active SiO2, which can effectively promote the formation of CSH gel, a hydration product, and improve the density and strength of the material. Fly ash is rich in glass microspheres, which can significantly improve the rheological properties of the slurry and contribute to the later strength due to its pozzolanic effect. Both can be used alone or in combination, depending on the specific characteristics of the tailings and the backfilling requirements, providing flexible adjustment options.

[0011] Preferably, the composite activator comprises sulfate and organic alcohol amine.

[0012] Beneficial effects: Sulfates (such as sodium sulfate) can provide SO4. 2- This promotes the formation of early strength phases such as ettringite; organic alcohol amines (such as triethanolamine) act as complexing agents and pH adjusters, gently complexing Fe in copper slag. 3+ Al 3+ The presence of metal ions promotes their dissolution and participation in the hydration reaction, while avoiding the corrosion problems of equipment and pipelines caused by strong alkaline activators. The combination of these two elements forms a dual synergistic activation mechanism of "sulfate activation strength + organic alcohol amine activation activity".

[0013] Preferably, the sulfate is sodium sulfate (Na₂SO₄); and / or, The organic alcohol amine is triethanolamine (TEA).

[0014] Preferably, the mass ratio of Na2SO4 to TEA is (4-5):1.

[0015] Beneficial effects: This ratio is key to ensuring the efficient synergy of the dual activation mechanism. At this ratio, Na2SO4 can provide sufficient sulfate ions to the system, ensuring the full formation of the early strength phase; and an appropriate amount of TEA (as an organic alcohol amine and complexing agent) can effectively activate the activity of the silica-alumina phase and promote the dissolution of metal ions, while an excessively high proportion of TEA may lead to an excessive increase in the pH of the system or affect the stability of the slurry.

[0016] Preferably, the method for preparing the copper carbide slag includes the following steps: The copper slag is mixed with a grinding aid and ground. The resulting copper slag powder is then mixed with a mineralization promoter and heated under a CO2 atmosphere to obtain the carbide copper slag.

[0017] Beneficial Effects: The above method achieves deep and efficient modification of copper slag through a three-step synergistic process of "mechanical grinding activation + mineralization promoter guidance + CO2-enhanced carbonation". Grinding releases the glassy structure, mineralization promoters (such as MgO and Ca(OH)2) guide the formation of nano-carbonates and reconstruct the microstructure during carbonation, while CO2 carbonation fixes carbon dioxide and generates a reinforcing phase. This process significantly enhances the chemical activity of the copper slag and achieves carbon fixation.

[0018] Preferably, the D of the copper slag powder v (50) (median particle size) is 6.5-7.5 μm (approximately 2000 mesh).

[0019] More preferably, the grinding time is 45-60 minutes.

[0020] Beneficial effects: The above-mentioned fineness range represents a balance between activity and energy consumption. Grinding to this fineness can fully break down copper slag particles, release the internally encapsulated glassy structure, and significantly increase the specific surface area and reactivity. If the fineness is too low (Dv(50) greater than 7.5μm), the activity release will be insufficient; if excessive fineness is pursued (Dv(50) less than 6.5μm), the grinding energy consumption will increase sharply, the economic efficiency will deteriorate, and the water demand of the slurry may increase.

[0021] Preferably, the grinding aid is triisopropanolamine; and / or, The mineralization promoter is MgO and / or Ca(OH)2.

[0022] More preferably, the grinding aid is added at a rate of 0.02-0.04% of the mass of the copper slag.

[0023] The amount of the mineralization accelerator added is 5-10% of the mass of the copper slag powder.

[0024] Beneficial Effects: This invention uses triisopropanolamine as a grinding aid. The hydroxyl and amino groups in its molecule can effectively adsorb onto the surface of copper slag particles, reducing agglomeration during grinding, significantly improving grinding efficiency, and ensuring the target fineness is achieved. Simultaneously, it can also complex iron ions in the copper slag, promoting their subsequent dissolution and reaction. MgO or Ca(OH)2 is chosen as a mineralization promoter because it can efficiently generate carbonates (such as magnesite and calcite) under a CO2 atmosphere. These nano-sized carbonates can fill pores and enhance the structure, while their formation process can further promote the dissolution of the silica-alumina phase in the copper slag, achieving a win-win situation of "carbon fixation" and "activation." The above-mentioned addition range ensures optimal results; too low a dosage will have little effect, while too high a dosage may introduce adverse effects or increase costs.

[0025] Preferably, the heating reaction is carried out at a temperature of 60-120°C for 2-6 hours, with a CO2 concentration of ≥20% and a pressure of 0.5-2 MPa.

[0026] Beneficial Effects: This combination of reaction conditions is key to ensuring a complete, efficient, and economically feasible carbonization reaction. A moderate heating temperature of 60-120℃ accelerates reaction kinetics while avoiding excessively high temperatures that could lead to a surge in energy consumption and potential product phase transitions. A reaction time of 2-6 hours is sufficient to complete the main carbonization process. A CO2 concentration ≥20% ensures the driving force of the reaction, while a pressure of 0.5-2 MPa further enhances the dissolution and diffusion of CO2 in the system, promoting gas-solid reactions. Under these conditions, 100-200 kg of CO2 can be fixed per ton of copper slag.

[0027] Application of a mine backfill cementitious material based on copper carbide slag in mine backfilling.

[0028] Beneficial effects: The cementitious material of the present invention is particularly suitable for the field of mine backfilling. It can directly or partially replace cement and use tailings from the mine itself to prepare slurry, realizing "waste treatment with waste" and significantly reducing backfilling costs and carbon emissions.

[0029] A mine backfill slurry, comprising the above-mentioned mine backfill cementitious material based on copper carbide slag, mine tailings and water; The mass ratio of the mine backfill cementitious material based on copper carbide slag to the mine tailings is 1:(6-12).

[0030] More preferably, the filling concentration of the mine filling slurry is 65-80%.

[0031] Beneficial effects: A mortar-to-sand ratio of 1:(6-12) and a filling concentration of 65-80% are proven suitable operating ranges. Within this range, the slurry has good fluidity (typically a slump ≥180mm), facilitating pipeline transport, while the filling material has sufficient density to ensure that the strength after curing meets the downhole support requirements. A concentration below 65% easily leads to bleeding and segregation, resulting in decreased strength; a concentration above 80% results in an overly thick slurry with high transport resistance.

[0032] Compared with the prior art, the present invention has the following advantages and technical effects: This invention uses triisopropanolamine as a grinding aid, which can further grind copper slag to D. V (50) = approximately 6.5~7.5 μm, thereby releasing the glassy structure and effectively improving the activity of copper slag; in addition, triisopropanolamine can effectively complex iron ions, further promoting the dissolution of iron. Simultaneously, this invention includes a dual activation mechanism: CO2 mineralization reaction generates nano-carbonates to fill pores, while simultaneously promoting the dissolution of the active silica-alumina phase. Furthermore, this invention utilizes carbon fixation synergistic effects, fixing 100-200 kg of CO2 gas per ton of copper slag, while simultaneously increasing the early strength of the cementitious material by more than 30%. Moreover, this invention, targeting the characteristics of the carbonized phase, employs a sulfate-organic alcohol amine composite activation system, which can effectively activate the activity of copper slag. Attached Figure Description The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 The XRD test results are for the copper slag raw material used in the embodiments of the present invention. Figure 2 The results of laser particle size analysis of the copper slag raw material used in the embodiments of the present invention; Figure 3 The results of laser particle size analysis of the copper slag powder obtained in Example 1 of this invention; Figure 4 The results of laser particle size analysis of tailings from a copper mine in Xinjiang used in this invention are shown. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] This invention discloses a mine backfill cementitious material based on copper carbide slag, comprising the following raw materials by mass fraction: The composition consists of 65-75% copper carbide slag, 20-30% auxiliary cementitious materials, and 3-8% composite activator.

[0036] In a preferred embodiment, the auxiliary cementing material is slag and / or fly ash.

[0037] In a preferred embodiment, the composite activator comprises sulfate and organic alcohol amine.

[0038] In a preferred embodiment, the sulfate is sodium sulfate (Na₂SO₄); and / or, The organic alcohol amine is triethanolamine (TEA).

[0039] In a preferred embodiment, the mass ratio of Na2SO4 to TEA is (4-5):1.

[0040] In a preferred embodiment, the method for preparing the copper carbide slag includes the following steps: The copper slag is mixed with a grinding aid and ground. The resulting copper slag powder is then mixed with a mineralization promoter and heated under a CO2 atmosphere to obtain the carbide copper slag.

[0041] In a preferred embodiment, the D of the copper slag powder v (50) is 6.5-7.5μm (about 2000 mesh).

[0042] In a more preferred embodiment, the grinding time is 45-60 minutes.

[0043] In a preferred embodiment, the grinding aid is triisopropanolamine; and / or, The mineralization promoter is MgO and / or Ca(OH)2.

[0044] In a more preferred embodiment, the grinding aid is added at a rate of 0.02-0.04% of the mass of the copper slag.

[0045] The amount of the mineralization accelerator added is 5-10% of the mass of the copper slag powder.

[0046] In a preferred embodiment, the heating reaction is carried out at a temperature of 60-120°C for 2-6 hours, with a CO2 concentration of ≥20% and a pressure of 0.5-2 MPa.

[0047] This invention also discloses the application of a mine backfill cementitious material based on copper carbide slag in mine backfilling.

[0048] This invention also discloses a mine backfill slurry, comprising the above-mentioned mine backfill cementitious material based on copper carbide slag, mine tailings, and water; The mass ratio of the mine backfill cementitious material based on copper carbide slag to the mine tailings is 1:(6-12).

[0049] In a more preferred embodiment, the filling concentration of the mine filling slurry is 65-80%.

[0050] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels; The copper slag was supplied by Yangxin Hongsheng Copper Industry Co., Ltd., and was produced using a "suspension flash smelting + suspension flash blowing" process. It is the tailings from the flash smelting furnace slag after slow cooling and mineral processing. Its main components are shown in Table 1 below, and the XRD analysis results are as follows. Figure 1 The particle size distribution was analyzed by a laser particle size analyzer as follows: Figure 2 As shown, its D V (50) = 16.0 μm, and the particle size distribution after grinding is as follows: Figure 3 .

[0051] Table 1 Main chemical components of copper slag The tailings are from a copper mine in Xinjiang. Their main chemical components are shown in Table 2, and their particle size distribution is shown in [Table 2]. Figure 4 .

[0052] Table 2 Main Chemical Components of Copper Tailings Unless otherwise specified, room temperature or normal temperature in the embodiments of the present invention refers to 25±3℃.

[0053] Example 1 A mine backfill cementitious material based on copper carbide slag, comprising the following raw materials by mass fraction: The composition consists of 65% copper carbide slag, 30% slag, and 5% composite activator (4% Na2SO4 + 1% TEA).

[0054] The preparation method of copper carbide slag includes the following steps: Triisopropanolamine (0.02% by weight of copper slag) was added to the copper slag as a grinding aid, and the mixture was ground in a planetary ball mill for 45 minutes. The resulting copper slag powder was D. v (50) = 7.49 μm, laser particle size analysis as follows Figure 3As shown. The obtained copper slag powder was mixed with 6% mineralization promoter (Ca(OH)2) and reacted for 5 hours under the conditions of CO2 concentration of 25% (volume concentration, the same below), pressure of 1.5MPa and temperature of 60℃ to obtain carbide copper slag.

[0055] Example 2 A mine backfill cementitious material based on copper carbide slag, comprising the following raw materials by mass fraction: The composition consists of 75% copper carbide slag, 22% slag, and 3% composite activator (2.5% Na2SO4 + 0.5% TEA).

[0056] The preparation method of copper carbide slag includes the following steps: Triisopropanolamine (0.03% by weight of copper slag) was added to the copper slag as a grinding aid, and the mixture was ground in a planetary ball mill for 50 minutes. The resulting copper slag powder was D. v (50) = 6.73 μm. The obtained copper slag powder was mixed with 6% mineralization promoter (MgO) and reacted for 4 h under the conditions of CO2 concentration of 30%, pressure of 1.0 MPa and temperature of 80℃ to obtain carbonized copper slag.

[0057] Example 3 A mine backfill cementitious material based on copper carbide slag, comprising the following raw materials by mass fraction: The composition consists of 70% copper carbide slag, 26% fly ash, and 4% composite activator (3.2% Na2SO4 + 0.8% TEA).

[0058] The preparation method of copper carbide slag includes the following steps: Triisopropanolamine (0.04% by weight of copper slag) was added to the copper slag as a grinding aid, and the mixture was ground in a planetary ball mill for 55 minutes. The resulting copper slag powder was D. v (50) = 7.06 μm. The obtained copper slag powder was mixed with 8% mineralization promoter (Ca(OH)2) and reacted for 3 h under the conditions of CO2 concentration of 25%, pressure of 1.2 MPa and temperature of 100℃ to obtain carbonized copper slag.

[0059] Example 4 A mine backfill cementitious material based on copper carbide slag, comprising the following raw materials by mass fraction: The composition consists of 72% copper carbide slag, 10% slag, 10% fly ash, and 8% composite activator (6.5% Na2SO4 + 1.5% TEA).

[0060] The preparation method of copper carbide slag includes the following steps: Triisopropanolamine (0.03% by weight of copper slag) was added to the copper slag as a grinding aid, and the mixture was ground in a planetary ball mill for 60 minutes. The resulting copper slag powder was D.v (50) = 6.62 μm. The obtained copper slag powder was mixed with 8% mineralization promoter (MgO) and reacted for 5 h under the conditions of CO2 concentration of 25%, pressure of 1.2 MPa and temperature of 80 °C to obtain carbide copper slag.

[0061] To verify the necessity and synergistic effect of the various technical features of this invention, the following comparative examples are provided: Comparative Example 1 (without composite activator) A mine backfill cementitious material based on copper carbide slag differs from Example 1 only in that the composite activator is replaced with an equal mass of inert filler stone powder. All other process steps and parameters are the same as in Example 1.

[0062] Comparative Example 2 (Single Sulfate Initiator) A mine backfill cementitious material based on copper carbide slag differs from Example 1 only in that the TEA in the composite activator is replaced with an equal mass of Na2SO4 (i.e., the activator is 5% Na2SO4). All other process steps and parameters are the same as in Example 1.

[0063] Comparative Example 3 (Different Auxiliary Cementitious Materials) A mine backfill cementitious material based on copper carbide slag differs from Example 1 only in that the slag is replaced with an equal mass of inactive filler, finely ground quartz sand. All other process steps and parameters are the same as in Example 1.

[0064] Comparative Example 4 (without mineralization accelerator) A mine backfill cementitious material based on copper carbide slag differs from Example 1 only in that no mineralization accelerator (Ca(OH)2) is added during the preparation of the copper carbide slag. All other process steps and parameters are the same as in Example 1.

[0065] Comparative Example 5 (coarsely ground copper slag) A mine backfill cementitious material based on copper carbide slag differs from Example 1 only in that the grinding process of the copper carbide slag is changed, and only a short-time grinding is performed. Specifically, it includes the following steps: Triisopropanolamine (0.02% by weight of copper slag) was added to the copper slag as a grinding aid. The slag was then ground in a planetary ball mill for 15 min. The resulting copper slag powder had a particle size of Dv(50) = 11.60 μm. The resulting copper slag powder was then mixed with 6% mineralization promoter (Ca(OH)2) and reacted for 5 h under conditions of CO2 concentration of 25%, pressure of 1.5 MPa, and temperature of 60 °C to obtain carbonized copper slag.

[0066] The remaining process steps and parameters are the same as in Example 1.

[0067] Technical effects: The copper slag-based cementitious materials of Examples 1-4 and Comparative Examples 1-5 were tested for cementing and backfilling performance with tailings from a copper mine in Xinjiang. They were also compared with Esheng PO 42.5 cement as the cementing material. The tests were conducted according to GB / T 39489-2020 "Technical Specification for Whole Tailings Paste Backfilling". Under the premise of ensuring a slump ≥180mm, the slurry backfilling mass concentration was determined to be 75%, and the cement-sand ratios were 1:6, 1:9, and 1:12, respectively. The specimens were cured in a constant temperature and humidity curing chamber at a temperature of (20±1)℃ and a humidity of 95%±5%. The specific steps are as follows: Copper tailings, the copper slag-based composite cementitious material from Examples 1-4 and Comparative Examples 1-5, and water (the amount of which was calculated based on a slurry filling mass concentration of 75%) were mixed evenly using a mixer to obtain a slurry. The prepared slurry was poured into a 70.7mm × 70.7mm × 70.7mm mold that had been brushed with lubricating oil. The mold was vibrated up and down to ensure that there were no air bubbles or very few air bubbles inside the filling slurry, while ensuring the slurry was slightly higher than the mold. After initial setting, the slurry was leveled and placed in a curing chamber. After 24 hours, the mold was removed, labels were affixed, and the specimens were placed in a constant temperature and humidity curing chamber for curing. The compressive strength of specimens cured for 7 days, 14 days, and 28 days was tested. The performance results are shown in Table 3.

[0068] Table 3. Strength results of copper slag-based cementitious materials and ordinary Portland cement filling specimens in various examples and comparative examples. The results show that the compressive strength of the copper slag-based cementitious material prepared by this method, with cement-sand ratios of 1:6, 1:9, and 1:12 and a filling concentration of 75%, is significantly higher than that of ordinary Portland cement and the comparative cementitious materials when the filling volume of the specimens is prepared using tailings synergistic composite cementitious material from a copper mine in Xinjiang. The advantage in compressive strength is even more pronounced at lower cement-sand ratios. At a cement-sand ratio of 1:6, the 28-day compressive strength of the filling reaches 5 MPa; at 1:9, it reaches 4 MPa; and at 1:12, it reaches approximately 2.5 MPa. Therefore, this meets the strength requirements of most mines for filling volumes.

[0069] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A mine backfill cementitious material based on copper carbide slag, characterized in that, Raw materials including the following mass fractions: The composition consists of 65-75% copper carbide slag, 20-30% auxiliary cementitious materials, and 3-8% composite activator.

2. The mine backfill cementitious material based on copper carbide slag according to claim 1, characterized in that, The auxiliary cementing material is slag and / or fly ash.

3. The mine backfill cementitious material based on copper carbide slag according to claim 1, characterized in that, The composite activator includes sulfates and organic alcohol amines.

4. The mine backfill cementitious material based on copper carbide slag according to claim 3, characterized in that, The sulfate is sodium sulfate; and / or, The organic alcohol amine is triethanolamine.

5. The mine backfill cementitious material based on copper carbide slag according to claim 1, characterized in that, The method for preparing the copper carbide slag includes the following steps: The copper slag is mixed with a grinding aid and ground. The resulting copper slag powder is then mixed with a mineralization promoter and heated under a CO2 atmosphere to obtain the carbide copper slag.

6. The mine backfill cementitious material based on copper carbide slag according to claim 5, characterized in that, The copper slag powder D v (50) is 6.5-7.5μm.

7. The mine backfill cementitious material based on copper carbide slag according to claim 5, characterized in that, The grinding aid is triisopropanolamine; and / or... The mineralization promoter is MgO and / or Ca(OH)2.

8. A mine backfill cementitious material based on copper carbide slag according to claim 5, characterized in that, The heating reaction is carried out at a temperature of 60-120℃ for 2-6 hours, with a CO2 concentration of ≥20% and a pressure of 0.5-2MPa.

9. The application of the mine backfill cementitious material based on copper carbide slag as described in any one of claims 1-8 in mine backfilling.

10. A mine backfill slurry, characterized in that, Includes the mine backfill cementitious material based on copper carbide slag as described in any one of claims 1-8, mine tailings and water; The mass ratio of the mine backfill cementitious material based on copper carbide slag to the mine tailings is 1:(6-12).

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