Electrolytic manganese residue cemented filling material and preparation method thereof

Abstract

This invention belongs to the field of solid waste resource utilization technology, specifically disclosing an electrolytic manganese slag cemented backfill material and its preparation method. The electrolytic manganese slag cemented backfill material provided by this invention comprises, by mass, 80-120 parts of electrolytic manganese slag, 7-15 parts of alkali treatment agent, 16-19 parts of composite cementitious agent, and 120-140 parts of water; wherein the alkali treatment agent includes red mud and calcium carbide slag; and the composite cementitious agent includes cement and slag. This invention uses a minimally processed electrolytic manganese slag as aggregate, subjecting it to only minimally intensive crushing without grinding, calcination, or washing. Through the "in-situ regulation" effect of a low-dosage alkali treatment agent and optimized pretreatment stirring time, it achieves synergistic optimization of ammonia nitrogen removal and backfill strength development, possessing advantages such as simple process, extremely low energy consumption, low cost, and large capacity for electrolytic manganese slag disposal.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and in particular to an electrolytic manganese slag cemented backfill material and its preparation method. Background Technology

[0002] Electrolytic manganese slag is an industrial byproduct of the electrolytic manganese industry, producing approximately 8-10 tons of slag for every ton of electrolytic manganese produced. my country generates a massive amount of electrolytic manganese slag annually. Large-scale stockpiling not only occupies valuable land resources, but also poses a serious environmental pollution problem, as harmful substances such as ammonia nitrogen and heavy metals may seep into the soil and groundwater. Therefore, developing large-scale disposal technologies for electrolytic manganese slag and realizing its resource utilization has become an urgent need for the green development of the electrolytic manganese industry.

[0003] Cemented backfilling technology is one of the important ways to dispose of electrolytic manganese slag on a large scale. Using electrolytic manganese slag as a backfill material for backfilling goaf areas in mines not only solves the problem of solid waste disposal, but also meets the needs of safe production in mines. However, there are the following technical bottlenecks in directly applying electrolytic manganese slag to backfilling: (1) Ammonia nitrogen inhibition problem: Electrolytic manganese slag contains a large amount of ammonia nitrogen (usually 2000~5000mg / kg). Under alkaline conditions, this ammonia nitrogen will react with hydroxide ions generated by the hydration of cementitious materials, inhibiting the hydration process of cementitious materials, resulting in slow strength development of backfill body, which is difficult to meet the strength requirements of mine backfilling. (2) High treatment cost: In order to solve the ammonia nitrogen inhibition problem, existing technologies usually require ammonia removal treatment of electrolytic manganese slag. Common methods include water washing for ammonia removal, alkali treatment for ammonia removal, etc., but these methods are often accompanied by subsequent processes such as solid-liquid separation, washing, and drying, which are long process flow, large equipment investment, and high operating costs. (3) Energy consumption problem: Some existing technologies attempt to improve the utilization rate of electrolytic manganese slag in building materials by stimulating the cementitious activity of electrolytic manganese slag, such as high-temperature calcination (1080~1180℃) and ball milling (to below 100 mesh), which consumes a lot of energy and is contrary to the requirements of low-carbon development. (4) Lack of optimization of pretreatment time: When treating electrolytic manganese slag, existing technologies often blindly extend the treatment time simply to pursue the ammonia nitrogen removal efficiency, ignoring the negative impact of overtreatment on the structure of the filling body, and failing to reveal the two-way regulation relationship between pretreatment time and filling body performance.

[0004] In summary, existing technologies for treating electrolytic manganese slag for use as backfill materials generally suffer from problems such as complex processes, high energy consumption, high costs, and a lack of optimized pretreatment parameters. Developing a backfill material preparation method that is simple, low-energy, low-cost, and can achieve synergistic optimization of ammonia nitrogen removal and strength development is of significant practical importance. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides an electrolytic manganese slag cemented backfill material and its preparation method, particularly a method for preparing a backfill material that uses minimally simplistic treatment of electrolytic manganese slag as aggregate, a low-dosage alkali treatment agent, and achieves synergistic performance through optimized pretreatment stirring time. This invention only involves minimally simplistic, slight crushing of the electrolytic manganese slag, eliminating the need for grinding, calcination, or washing. Through the "in-situ regulation" effect of a low-dosage alkali treatment agent and optimized pretreatment stirring time, it achieves synergistic optimization of ammonia nitrogen removal and backfill strength development, offering advantages such as simple process, extremely low energy consumption, low cost, and large capacity for electrolytic manganese slag disposal.

[0006] In a first aspect, the present invention provides an electrolytic manganese slag cemented backfill material, wherein the raw material components include, by mass parts: 80-120 parts of electrolytic manganese slag, 7-15 parts of alkali treatment agent, 16-19 parts of composite cementitious agent and 120-140 parts of water;

[0007] The alkali treatment agent includes red mud and carbide slag; the composite cementitious agent includes cement and slag.

[0008] According to specific embodiments of the present invention, the electrolytic manganese slag cemented backfill material provided by the present invention enables the large-scale disposal of electrolytic manganese slag and the synergistic utilization of industrial solid wastes such as red mud, carbide slag and ore slag, realizing the green development concept of "treating waste with waste".

[0009] According to some embodiments of the present invention, the raw material components include, by mass parts: 90-110 parts of electrolytic manganese slag, 8-14 parts of alkali treatment agent, 16-19 parts of composite gelling agent and 120-140 parts of water.

[0010] According to some preferred embodiments of the present invention, the mass of the alkali treatment agent is 9% to 12% of the mass of the electrolytic manganese slag.

[0011] According to some embodiments of the present invention, the mass ratio of red mud to carbide slag in the alkali treatment agent is (0~0.3):1; the mass ratio of cement to slag in the composite cementitious agent is (0.25~1.5):1.

[0012] According to some preferred embodiments of the present invention, the mass ratio of red mud to carbide slag in the alkali treatment agent is (0.2~0.3):1; the mass ratio of cement to slag in the composite cementitious agent is (0.5~1):1.

[0013] This invention explores the optimal ratio and dosage of alkali treatment agent and composite cementitious agent, as well as their incorporation amount in electrolytic manganese slag cemented backfill material.

[0014] The alkaline treatment agents used in this invention include red mud and carbide slag. The main alkaline component of red mud is NaOH, and the main alkaline component of carbide slag is Ca(OH)₂. Ca(OH)₂ has limited solubility in solution. If NaOH is added to a supersaturated solution of Ca(OH)₂, the OH⁻ concentration in the solution will further increase. - The concentration of red mud increases the ammonia nitrogen removal efficiency, but at the same time, the red mud has a weak alkalinity, providing less OH-. - Due to limited capacity, the proportion of red mud in the alkali treatment agent should not be too high when the amount of alkali treatment agent added is limited. Therefore, the optimal ratio of red mud to carbide slag in the alkali treatment agent was determined. Simultaneously, to ensure the alkali treatment effect of electrolytic manganese slag and to increase the amount of electrolytic manganese slag that can be disposed of, the amount of alkali treatment agent added was determined to be 9%~12% of the mass of electrolytic manganese slag. The composite cementitious agent of this invention includes cement and slag, and is used in electrolytic manganese slag with high SO4 content. 2- Under the influence of certain concentrations, cement hydration is inhibited, while slag reacts with SO4. 2- It has a good synergistic effect in SO4 2- Under the dual stimulation of alkali and cement, slag has a higher potential for strength development. However, the increase in the proportion of slag inhibits the formation of ettringite in cement-slag composite cementitious agent to a certain extent, resulting in slow strength development. Therefore, cement-slag composite cementitious agent has the best ratio in electrolytic manganese slag cemented backfill material, and the optimal mass ratio of cement and slag was finally determined.

[0015] According to some embodiments of the present invention, the water content of the electrolytic manganese slag is 4% to 10%, and the mass fraction of the electrolytic manganese slag is calculated on a dry basis, with the remaining moisture included in the mass fraction of water.

[0016] A second aspect of the present invention provides a method for preparing an electrolytic manganese slag cemented backfill material as described in the first aspect of the present invention, comprising the following steps:

[0017] S1. The electrolytic manganese slag is crushed and sieved to obtain crushed electrolytic manganese slag with a particle size of 1.5~4mm. It is then mixed with an alkali treatment agent, water is added and stirred. After standing, the electrolytic manganese slag slurry is obtained.

[0018] S2. Mix the electrolytic manganese slag slurry with the composite binder and stir to obtain the filling slurry;

[0019] S3. Fill the filling slurry into blocks and cure them to obtain the electrolytic manganese slag cemented filling material.

[0020] According to some embodiments of the present invention, in step S1, the crushing is carried out by crushing with a crusher at a speed of 32,000 to 36,000 rpm for a time of 15 to 30 seconds.

[0021] According to some embodiments of the present invention, in step S1, the sieving process is to pass the material through 6-mesh and 10-mesh sieves to obtain crushed electrolytic manganese slag with a particle size of 2~3.35mm.

[0022] According to some embodiments of the present invention, in step S1, the stirring speed is 200~300 rpm and the stirring time is 20~40 min; preferably, the stirring time is 25~35 min.

[0023] This invention reveals a "two-way regulation" mechanism of pretreatment stirring time on the performance of the backfill: on the one hand, extending the stirring time is beneficial for ammonia nitrogen release; on the other hand, the escape of ammonia gas leads to additional pores in the backfill, increasing porosity and decreasing strength. This invention achieves a balance between ammonia nitrogen removal efficiency and backfill strength by limiting the stirring time within this range. Those skilled in the art, based on existing technology, could not have foreseen that excellent ammonia nitrogen removal efficiency and good backfill strength could be obtained simultaneously within such a narrow stirring time window. Traditional methods, when treating electrolytic manganese slag, often blindly extend the treatment time simply to pursue ammonia nitrogen removal efficiency, ignoring the negative impact of overtreatment on the backfill structure.

[0024] According to some embodiments of the present invention, in step S2, the stirring speed is 200~300 rpm and the time is 20~40 min.

[0025] According to some embodiments of the present invention, in step S3, the curing temperature is 19~21℃, the relative humidity is 93%~97%, and the time is 7~28 days.

[0026] This invention utilizes electrolytic manganese slag based on a "coarse crushing → aggregate production" technical route, which differs from the traditional "ultrafine processing → gelation" route. Therefore, the pretreatment degree of this invention differs from traditional methods. Traditional methods typically require drying and ball milling of the electrolytic manganese slag until the particle size is ≤150μm (passing through a 100-mesh sieve), using it as a gelling component. This invention, however, only slightly crushes the electrolytic manganese slag, allowing it to pass through a 6-mesh sieve (particle size ≤3.35mm), without any drying, grinding, or calcination. The difference in particle size is between micrometers and millimeters, resulting in a significant difference in energy consumption. This invention only requires simple crushing (15~30s, energy consumption approximately 0.5~1kWh / ton) and stirring, with a comprehensive energy consumption of approximately 2%~5% of existing technologies.

[0027] The beneficial effects of this invention are:

[0028] 1) The process is greatly simplified: This invention only requires slight crushing of electrolytic manganese slag, without any deep processing steps such as grinding, calcination, drying, water washing, solid-liquid separation, washing, and drying; the entire process only includes five steps: "crushing → mixing and stirring → settling → re-stirring → filling and curing", which is simple to operate and requires less equipment investment;

[0029] 2) Since no reduction treatment is required for the electrolytic manganese slag, the utilization rate of the electrolytic manganese slag in this invention is close to 100%; in the filling material, the proportion of crushed electrolytic manganese slag can reach more than 70%, realizing the large-scale disposal of electrolytic manganese slag;

[0030] 3) Environmental and cost advantages: This invention only requires a crusher and mixing equipment, eliminating the need for high-energy-consuming equipment such as drying equipment, ball mills, and calcining kilns; the overall energy consumption is approximately 2% to 5% of traditional technologies, reducing CO2 emissions by more than 90%; furthermore, the red mud and carbide slag used in this invention are both industrial solid wastes, widely available and inexpensive; no high-temperature calcination, drying, or grinding is required, significantly reducing energy costs; the overall cost is more than 60% lower than traditional technologies.

[0031] 4) Excellent product performance: The electrolytic manganese slag cemented backfill prepared by this invention can achieve a 28-day compressive strength of over 0.84 MPa, meeting the basic strength requirements for mine backfill (≥0.7 MPa); compared with untreated electrolytic manganese slag backfill, the strength is increased by more than 10 times; this invention also optimizes the pretreatment stirring time, which can achieve efficient ammonia nitrogen removal while maintaining good strength of the backfill. Compared with long stirring time (>40 min), the stirring of this invention can increase the 28-day compressive strength of the backfill by 35%~70%, while the ammonia nitrogen concentration of the effluent can still be controlled at a low level, avoiding structural deterioration caused by overtreatment.

[0032] 5) This invention avoids the emission of waste gas generated by high-temperature calcination and the problem of treating ammonia-containing wastewater generated by water washing and ammonia removal. At the same time, red mud and carbide slag, two types of industrial solid waste, are synergistically utilized in this invention, realizing the green development concept of "treating waste with waste".

[0033] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0035] Figure 1 This is a SEM image of the microstructure of the original electrolytic manganese slag of this invention.

[0036] Figure 2This is a SEM image of the microstructure of the electrolytic manganese slag cemented backfill prepared in Example 1 of the present invention;

[0037] Figure 3 This is a SEM image of the microstructure of the electrolytic manganese slag cemented backfill prepared in Example 2 of the present invention;

[0038] Figure 4 This is a SEM image of the microstructure of the electrolytic manganese slag cemented backfill prepared in Comparative Example 1 of this invention.

[0039] Figure 5 This is a SEM image of the microstructure of the electrolytic manganese slag cemented backfill prepared in Comparative Example 2 of this invention. Detailed Implementation

[0040] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0041] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0042] Some of the main raw materials used in the specific implementation:

[0043] Electrolytic manganese slag: The electrolytic manganese slag used in this invention came from a manganese mining company in Guizhou Province. It was aged electrolytic manganese slag, appearing as black lumps or granules, with a moisture content of 4.43% and a pH value of 6.52. The elemental composition of the electrolytic manganese slag was analyzed using X-ray fluorescence spectroscopy (XRF), and the results are shown in Table 1.

[0044] Red mud: The red mud used in this invention came from an environmental protection company in Shandong Province. It was Bayer process red mud, appearing as a reddish-brown powder with a pH of 10.56. The elemental composition of the red mud was analyzed using XRF, and the results are shown in Table 2.

[0045] Calcium carbide slag: The calcium carbide slag used in this invention was obtained from an environmental protection company in Shandong Province. It appeared as a grayish-white powder with a pH value of 12.52. The elemental composition of the calcium carbide slag was analyzed using XRF, and the results are shown in Table 3.

[0046] Slag: The slag used in this invention is S95 grade slag, produced in Zhengzhou, Henan Province, and appears as a white powder. The elemental composition of the slag was analyzed using XRF, and the results are shown in Table 4.

[0047] Example 1

[0048] This embodiment provides a method for preparing an electrolytic manganese slag cemented backfill material. The specific preparation steps are as follows:

[0049] 1) The electrolytic manganese slag is lightly crushed (crusher 34000rpm, 15~30s), and passed through 6-mesh and 10-mesh sieves (controlling the particle size of the crushed electrolytic manganese slag to 2~3.35mm). No grinding, calcination, drying, or washing is required to obtain the crushed electrolytic manganese slag, with a microstructure as shown below. Figure 1 As shown, the particle morphology is mainly plate-like and rod-like.

[0050] 2) Pretreatment of crushed electrolytic manganese slag: 53.55g of calcium carbide slag is used as an alkali treatment agent; 595g of crushed electrolytic manganese slag (on a dry basis) is added to the alkali treatment agent (alkali treatment agent: crushed electrolytic manganese slag = 9:100), and 753.55g of water is added (this is the total calculated amount of water; when actually adding water, the free water contained in the electrolytic manganese slag needs to be subtracted) and mixed; the mixture is stirred at 300rpm for 30min to obtain electrolytic manganese slag slurry, which is then allowed to stand for 24h.

[0051] 3) Preparation of electrolytic manganese slag cemented filling slurry: Take 42g of cement and 63g of slag (cement: slag = 2:3) and mix them to obtain a composite cementitious agent; mix the electrolytic manganese slag slurry with the composite cementitious agent and stir at 300rpm for 30min in a mixer to obtain electrolytic manganese slag cemented filling slurry;

[0052] 4) Preparation of electrolytic manganese slag cemented backfill: The backfill slurry was filled into test blocks (40×40×40mm), and placed in a constant temperature and humidity chamber for curing for 28 days. The curing temperature was 20℃ and the relative humidity was 95%, thus obtaining electrolytic manganese slag cemented backfill.

[0053] Example 2

[0054] This embodiment provides a method for preparing an electrolytic manganese slag cemented backfill material. The specific preparation steps are as follows:

[0055] 1) The electrolytic manganese slag is slightly crushed (crusher 34000rpm, 15~30s), and passed through 6-mesh and 10-mesh sieves (controlling the particle size of the crushed electrolytic manganese slag to 2~3.35mm). No grinding, calcination, drying or washing is required to obtain crushed electrolytic manganese slag.

[0056] 2) Pretreatment of crushed electrolytic manganese slag: Mix 14.28g of red mud and 57.12g of calcium carbide slag to obtain an alkali treatment agent (red mud: calcium carbide slag = 0.25:1); Take 595g of crushed electrolytic manganese slag (on a dry basis), add 71.40g of alkali treatment agent (alkali treatment agent: crushed electrolytic manganese slag = 12:100), add 771.40g of water (this is the total calculated amount of water; when actually adding water, the free water contained in the electrolytic manganese slag should be subtracted) and mix; stir at 300rpm for 30min to obtain electrolytic manganese slag slurry, and let stand for 24h;

[0057] 3) Preparation of electrolytic manganese slag cemented filling slurry: Take 42g of cement and 63g of slag (cement: slag = 2:3) and mix them to obtain a composite cementitious agent; mix the electrolytic manganese slag slurry with the composite cementitious agent and stir at 300rpm for 30min in a mixer to obtain electrolytic manganese slag cemented filling slurry;

[0058] 4) Preparation of electrolytic manganese slag cemented backfill: The backfill slurry was filled into test blocks (40×40×40mm), and placed in a constant temperature and humidity chamber for curing for 28 days. The curing temperature was 20℃ and the relative humidity was 95%, thus obtaining electrolytic manganese slag cemented backfill.

[0059] Comparative Example 1

[0060] This comparative example provides a method for preparing an electrolytic manganese slag cemented backfill material. This comparative example is basically the same as Example 2, except that in step 2) of this comparative example, no alkali treatment agent is added and mixed with the electrolytic manganese slag; the remaining steps are the same as in Example 1.

[0061] Comparative Example 2

[0062] This comparative example provides a method for preparing an electrolytic manganese slag cemented backfill material. This comparative example is basically the same as Example 2, except that in step 2) of this comparative example, all the carbide slag is replaced with red mud, which is used as an alkali treatment agent and mixed with the electrolytic manganese slag; the remaining steps are the same as in Example 1.

[0063] Comparative Example 3

[0064] This comparative example provides a method for preparing an electrolytic manganese slag cemented backfill material. This comparative example is basically the same as Example 1, except that in step 2) of this comparative example, all the carbide slag is replaced with calcium oxide to obtain an alkali treatment agent mixed with electrolytic manganese slag; the remaining steps are the same as in Example 1.

[0065] Comparative Example 4

[0066] This comparative example provides a method for preparing an electrolytic manganese slag cemented backfill material. This comparative example is basically the same as Example 2, except that in step 2) of this comparative example, the stirring time of the mixer is extended to 60 min; the remaining steps are the same as in Example 1.

[0067] Comparative Example 5

[0068] This comparative example provides a method for preparing an electrolytic manganese slag cemented backfill material. This comparative example is basically the same as Example 2, except that in step 3) of this comparative example, 84g of cement and 21g of slag (cement: slag = 4:1) are mixed to obtain a composite cementitious agent; the remaining steps are the same as in Example 1.

[0069] Comparative Example 6

[0070] This comparative example provides a method for preparing a cemented backfill material made from electrolytic manganese slag. This comparative example is basically the same as Example 1, except that in step 1) of this comparative example, the electrolytic manganese slag is slightly crushed (crusher 34000rpm, 10~15s) and passed through 2-mesh and 6-mesh sieves (controlling the particle size of the crushed electrolytic manganese slag to be 3.35~10mm); the remaining steps are the same as in Example 1.

[0071] Comparative Example 7

[0072] This comparative example provides a method for preparing a cemented backfill material made from electrolytic manganese slag. This comparative example is basically the same as Example 1, except that in step 1) of this comparative example, the electrolytic manganese slag is slightly crushed (crusher 34000rpm, 20~40s) and passed through a 10-mesh sieve (to control the particle size of the crushed electrolytic manganese slag to be <2mm); the remaining steps are the same as in Example 1.

[0073] Electron microscopy observation:

[0074] The SEM images of the microstructures of the cemented fillers prepared in Examples 1, 2, Comparative Examples 1 and 2 are shown below. Figure 2 , 3 As shown in Figures 4 and 5.

[0075] Observing the SEM images of the microstructure, compared with Comparative Example 1, Example 1 showed a large number of needle-like and gel-like products adhering to the electrolytic manganese slag particles, causing the particles to stick together. This is because the electrolytic manganese slag without alkali treatment contains a large amount of ammonia nitrogen, and the alkaline substances in the gelling agent are consumed by the ammonia nitrogen, inhibiting the hydration of the gelling agent. However, after the electrolytic manganese slag is treated with alkali treatment, the gelling agent obtains a suitable hydration environment, generating a large number of hydration products, thereby enabling the electrolytic manganese slag filling body to form a certain strength.

[0076] Furthermore, compared to the microstructure of Example 1, the hydration products in Example 2 are more concentrated, with needle-like and rod-shaped products overlapping between the electrolytic manganese slag particles. Simultaneously, the gel products also promote particle adhesion, resulting in a tighter connection between the electrolytic manganese slag particles. This is because, compared to Example 1, the alkali treatment agent in Example 2 accounts for 12% of the electrolytic manganese slag, and synergistic pretreatment of red mud and calcium carbide slag is achieved. This results in a better pretreatment effect on the electrolytic manganese slag, providing a favorable hydration environment for the gelling agent and thus generating more hydration products.

[0077] As can be seen from the microstructure image of Comparative Example 2, under the pretreatment conditions of pure red mud, the microstructure is still mainly composed of plate-like and granular particles. No needle-like products or continuous gel phase were observed, showing a relatively loose microstructure. This indicates that under the condition of limited alkali treatment agent, pure red mud cannot achieve the pretreatment of electrolytic manganese slag, and the filling body prepared by it has a greater impact on the environment and has lower strength.

[0078] Performance testing:

[0079] The 28-day compressive strength, effluent ammonia nitrogen, 28-day leaching ammonia nitrogen, and porosity of the filling materials prepared in each embodiment and comparative example were tested. The compressive strength was tested according to JGJ / T 70-2009 "Standard for Test Methods of Basic Performance of Building Mortar", the ammonia nitrogen concentration was tested according to HJ 535-2009 "Determination of Ammonia Nitrogen in Water Quality by Nessler's Reagent Spectrophotometric Method", and the porosity was determined by nuclear magnetic resonance technology. The results are shown in Table 5.

[0080] The test results above show that the embodiments of the present invention, based on a simple process and low energy consumption, prepare electrolytic manganese slag cemented backfill with high strength performance. Only slight crushing of the electrolytic manganese slag is required, without grinding, calcination, drying, or washing. Pretreatment with a low-dosage alkali treatment agent (red mud, carbide slag solid waste) of 9%~12% is performed, with the pretreatment stirring time controlled within the range of 20~40 minutes. Without altering the aggregate properties of the electrolytic manganese slag, efficient removal of ammonia nitrogen and optimization of the cementitious agent hydration environment are simultaneously achieved. This invention can meet the basic strength requirements (≥0.7MPa) for mine backfilling, achieve 100% utilization and large-scale disposal of electrolytic manganese slag solid waste, and the remaining auxiliary materials are mostly industrial solid waste, widely available and inexpensive. The solution of this invention can significantly improve the economic benefits of relevant enterprises and is environmentally friendly, realizing the green development concept of "treating waste with waste."

[0081] The crushed electrolytic manganese slag in Comparative Example 1 was not treated with the alkali treatment agent proposed in this invention, which resulted in the inability to remove ammonia nitrogen from the filling material and the lack of in-situ regulation by the alkali treatment agent, affecting the hydration of the subsequent gelling agent, significantly reducing its strength performance, and the concentrations of ammonia nitrogen in the effluent and leaching at 28 days were extremely high.

[0082] The alkaline treatment agent used in Comparative Example 2 lacked carbide slag and only used red mud as the alkaline treatment agent. The ammonia nitrogen removal effect and in-situ control effect were poor, resulting in high ammonia nitrogen concentration in the slurry effluent. The prepared filling body had low strength performance and a large environmental impact.

[0083] In Comparative Example 3, calcium oxide was replaced with calcium carbide slag. Although good strength performance of the backfill was also achieved, the cost difference between calcium oxide and calcium carbide slag is huge. According to the general market price, calcium oxide costs 600 yuan / ton and calcium carbide slag costs 130 yuan / ton. The cost of Comparative Example 3 increased significantly. Therefore, the backfill prepared using calcium carbide slag has a huge cost advantage when the strength meets the requirements.

[0084] In Comparative Example 4, extending the stirring time during the pretreatment of electrolytic manganese slag slurry can further improve the ammonia nitrogen removal efficiency, but at the same time, the porosity of the prepared filling body increases by 2.0%, which leads to a decrease in strength. This indicates that although excessively extending the stirring time can further improve the ammonia nitrogen removal rate, it will lead to a significant decrease in the strength of the filling body. Therefore, longer stirring time does not necessarily result in better overall effects.

[0085] Comparative Example 5, compared to Example 2, adjusted the ratio of the composite cementitious agent. The strength performance of the filling material prepared with the composite cementitious agent using a higher cement ratio decreased, indicating that in the present invention, more cement is not necessarily better. Compared to cement, slag has good cementing properties in electrolytic manganese slag cemented filling materials. However, the increase in the proportion of slag also inhibits the formation of ettringite to some extent, resulting in slow strength development. Therefore, the cement and slag in the composite cementitious agent need to meet a certain ratio to achieve better results. The present invention uses more slag to achieve better strength performance while reducing costs.

[0086] In Comparative Example 6, the excessively large particle size of the crushed electrolytic manganese slag caused agglomeration during the pretreatment mixing process. Specifically, the electrolytic manganese slag was highly viscous, and during water addition and mixing, before the slag dissolved in water, the particles adhered to each other, continuously agglomerated, and eventually settled into spherical sediments at the bottom of the slurry. Simultaneously, this agglomeration resulted in poor alkali treatment and a high concentration of ammonia nitrogen in the slurry effluent. Although increasing the mixing time could improve this situation to some extent, as shown in Comparative Example 4, excessively long mixing times negatively impacted the strength of the filling material. In conclusion, excessively large particle size of the electrolytic manganese slag hindered the pretreatment process, resulting in poor uniformity of the electrolytic manganese slag slurry and hindering the successful completion of subsequent filling steps.

[0087] Compared to Example 1, Comparative Example 7 further reduced the particle size of electrolytic manganese slag. However, the results showed that the various properties of its filling material did not change significantly compared to Example 1. This indicates that when the crushed particle size of aged electrolytic manganese slag is below 3.35 mm, further refining the particle size will not have a significant positive impact on the cemented filling material of electrolytic manganese slag, but will only increase the energy consumption caused by crushing.

[0088] In summary, this invention breaks through the technical biases in the prior art that "electrolytic manganese slag must be ultra-finely processed before it can be utilized" and "the longer the pretreatment time, the better," and provides a truly low-carbon, simple, and economical resource utilization solution for electrolytic manganese slag.

[0089] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A cemented backfill material for electrolytic manganese slag, characterized in that, The raw material components, by mass parts, include: 80-120 parts of electrolytic manganese slag, 7-15 parts of alkali treatment agent, 16-19 parts of composite cementitious agent, and 120-140 parts of water; The alkali treatment agent includes red mud and carbide slag; the composite cementitious agent includes cement and slag.

2. The electrolytic manganese slag cemented backfill material according to claim 1, characterized in that, The mass ratio of red mud to carbide slag in the alkali treatment agent is (0~0.3):1; the mass ratio of cement to slag in the composite cementitious agent is (0.25~1.5):

1.

3. The electrolytic manganese slag cemented backfill material according to claim 1, characterized in that, The water content of the electrolytic manganese slag is 4% to 10%, and the mass fraction of the electrolytic manganese slag is calculated on a dry basis, with the remaining moisture included in the mass fraction of water.

4. The preparation method of the electrolytic manganese slag cemented backfill material according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. The electrolytic manganese slag is crushed and sieved to obtain crushed electrolytic manganese slag with a particle size of 1.5~4mm. It is then mixed with an alkali treatment agent, water is added and stirred. After standing, the electrolytic manganese slag slurry is obtained. S2. Mix the electrolytic manganese slag slurry with the composite binder and stir to obtain the filling slurry; S3. Fill the filling slurry into blocks and cure them to obtain the electrolytic manganese slag cemented filling material.

5. The preparation method according to claim 4, characterized in that, In step S1, the crushing is carried out by crushing with a crusher at a speed of 32,000 to 36,000 rpm for a time of 15 to 30 seconds.

6. The preparation method according to claim 4, characterized in that, In step S1, the sieving process involves passing the material through 6-mesh and 10-mesh sieves to obtain crushed electrolytic manganese slag with a particle size of 2~3.35mm.

7. The preparation method according to claim 4, characterized in that, In step S1, the stirring speed is 200~300 rpm and the stirring time is 20~40 min.

8. The preparation method according to claim 4, characterized in that, In step S2, the stirring speed is 200~300 rpm and the stirring time is 20~40 min.

9. The preparation method according to claim 4, characterized in that, In step S3, the curing temperature is 19~21℃, the relative humidity is 93%~97%, and the time is 7~28 days.

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