Environment-friendly curing agent for mine filling and preparation method thereof

Abstract

The invention discloses an environment-friendly curing agent for mine filling and a preparation method thereof, and belongs to the technical field of mine filling, the curing agent comprises the following components by mass: 30-50 parts of cement clinker, 10-20 parts of superfine slag powder, 5-15 parts of fly ash, 3-8 parts of gypsum, 1-5 parts of an active activator, and 0.5-2 parts of an additive. Wherein the active exciting agent is a compound of an alkali exciting agent and a sulfate exciting agent and can also be one of the alkali exciting agent and the sulfate exciting agent; the additive comprises one or more of a water reducing agent, an early strength agent and a water-retaining agent. According to the environment-friendly curing agent for mine filling and the preparation method thereof, by adding a proper amount of the active exciting agent, the activity of the superfine slag powder and the fly ash can be effectively excited, the early strength of the curing agent is improved, the curing agent can be rapidly cured after filling, a stable filling body is formed, and timely support is provided for a mine.

Description

Technical Field

[0001] The invention relates to the technical field of mine filling, and in particular to an environmentally friendly mine filling curing agent and a preparation method thereof. Background Art

[0002] Filling mine cavities is a common tailings treatment method that can effectively reduce the accumulation of tailings and reduce its negative impact on the environment. Backfilling technology is to mix tailings with filling materials and then backfill them into the mine to fill the goaf, support the ore body and prevent surface collapse. As a key component of the filling material, the performance of the solidifying agent directly affects the strength and stability of the filling body.

[0003] There are some problems with traditional mine filling curing agents. On the one hand, some curing agents have complex ingredients, high costs, and may contain environmentally unfriendly substances, which are not in line with the development concept of green mines. On the other hand, some curing agents are mostly cement-based, with poor curing effects and low early strength, which cannot meet the actual needs of rapid curing. In addition, the compatibility of curing agents with tailings slurry and their adaptability under different environmental conditions also need to be further improved. Therefore, the development of an environmentally friendly curing agent for mine filling has important practical significance. Summary of the invention

[0004] The content of this application is used to introduce concepts in a brief form, which will be described in detail in the detailed implementation section below. The content of this application is not intended to identify the key features or essential features of the technical solution claimed for protection, nor is it intended to limit the scope of the technical solution claimed for protection.

[0005] In order to overcome the deficiencies of the prior art, the present invention provides an environmentally friendly mine filling curing agent and a preparation method thereof.

[0006] To achieve the above object, the present invention provides the following technical solution: an environmentally friendly curing agent for mine filling, the composition and mass fraction of the curing agent are:

[0007] 30-50 parts of cement clinker, 10-20 parts of slag powder, 5-15 parts of fly ash, 3-8 parts of gypsum, 1-5 parts of active activator, 0.5-2 parts of admixture, including:

[0008] The active stimulant is a compound of an alkali stimulant and a sulfate stimulant, and can also be one of an alkali stimulant or a sulfate stimulant;

[0009] The admixture includes one or more of a water reducing agent, an early strength agent, and a water retaining agent, and the amount of the admixture added is 0.5%-2% of the total weight of the curing agent;

[0010] The specific surface area of ​​the slag powder is greater than 400m² / kg. 2 O 3 Content ≤1.5%;

[0011] The fly ash is Grade II or Grade III fly ash, with a loss on ignition of ≤8%;

[0012] The gypsum is natural gypsum or industrial by-product gypsum, and the content of calcium sulfate dihydrate is ≥85%.

[0013] Preferably, the alkaline activator is a mixture of sodium hydroxide and water glass with a purity of ≥95%, and the sulfate activator is sodium sulfate or potassium sulfoaluminate.

[0014] Preferably, the admixture includes 0.2-0.8% polycarboxylate water reducing agent, 0.1-0.5% hydroxypropyl methylcellulose water retaining agent, and 0.2-0.7% calcium formate early strength agent, and the total addition amount does not exceed 2% of the mass of the curing agent.

[0015] Preferably, the cement clinker is silicate cement clinker, wherein C 3 S content ≥50%, f-CaO ≤1.2%, gypsum dosage controls SO 3 Content 2.8-3.5%.

[0016] The present invention provides another technical solution: a method for preparing an environmentally friendly curing agent for mine filling, comprising the following steps:

[0017] S1. Grind slag powder and cement clinker separately to a specific surface area ≥ 380m² / kg;

[0018] S2, using gradient mixing process:

[0019] a. Premix the ground cement clinker and slag powder in proportion at 400-600r / min for 5-8min. During the premixing process, intermittent pulse stirring is adopted, and high-speed stirring is performed for 10-15 seconds every 2min to promote the initial uniform distribution of the raw materials;

[0020] b. Add fly ash, gypsum and active activator in proportion, stir vigorously at 750-900r / min for 15-20min under nitrogen protection, and introduce a certain amount of water vapor during the strong stirring process, and control the humidity at 30%-50%; among which, the fineness modulus of fly ash is 2.0-3.0, the water requirement ratio is ≤95%, and the gypsum needs to be pre-dried before mixing, and its moisture content is controlled to be ≤5%;

[0021] c. Add admixtures and continue to mix evenly, then homogenize the mixed materials;

[0022] S3. The homogenized material is aged for 24-72 hours at a relative humidity of ≤35% and a temperature of 20-30°C.

[0023] Preferably, the grinding in step 1 adopts a closed-circuit grinding system of a roller press combined with a ball mill, and 0.05-0.15% of triethanolamine is added as a grinding aid.

[0024] Preferably, in step 2b, the nitrogen protection oxygen content is ≤5%, and the temperature during the stirring process is controlled at 40-60°C.

[0025] Preferably, the aging process in step 3 adopts a dynamic compost turning process, the compost is turned once every 8 hours, the pile height does not exceed 1.5m, and the temperature and humidity of the material are regularly monitored during the aging process, and the environmental parameters are adjusted in time according to the monitoring data.

[0026] Preferably, the homogenization process in step 2c is carried out in two steps: primary homogenization and deep homogenization.

[0027] a. Primary homogenization: Use a double-shaft spiral homogenizer at a working pressure of 0.2-0.4MPa for 30-45min;

[0028] The speed gradient of the dual-axis spiral is controlled as follows: 20-30r / min in the first 15min, and then increased to 35-45r / min in the later stage;

[0029] The material temperature is controlled at 40-50°C by jacket cooling;

[0030] b. Deep homogenization: The material after primary homogenization is transported to a continuous homogenization bin and treated continuously for 24-48 hours under gas fluidization with an air flow velocity of 0.8-1.2 m / s;

[0031] Among them, the continuous homogenization bin is divided into three temperature control zones, which are: Zone I: 50-60℃ hot air activation, residence time 8-12h; Zone II: 35-45℃ constant temperature aging, residence time 10-14h; Zone III: 25-30℃ cooling stabilization, residence time 6-10h;

[0032] The wind speed ratio of each zone is controlled at Ⅰ:Ⅱ:Ⅲ=1.5:1:0.8.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention proposes an environmentally friendly solidifying agent for mine filling and a preparation method thereof. By adding an appropriate amount of active stimulant, the activity of slag powder and fly ash is effectively stimulated, and the early strength of the solidifying agent is significantly improved, so that it can be quickly solidified after filling to form a stable filling body, providing reliable support for the mine and ensuring the safety of mining operations.

[0035] 2. The present invention proposes an environmentally friendly solidifying agent for mine filling and a preparation method thereof. By optimizing the formula and reasonably matching the additives, the solidifying agent can undergo hydration reaction and complete coagulation and solidification in a short time after being mixed with water, which greatly shortens the filling operation cycle and improves the mining operation efficiency.

[0036] 3. The environmentally friendly solidifying agent for mine filling and its preparation method proposed in the present invention adopts industrial waste residues such as slag powder and fly ash as the main raw materials, which not only realizes the resource utilization of waste and reduces production costs, but also meets environmental protection requirements and has significant economic and social benefits.

[0037] 4. The present invention proposes an environmentally friendly mine filling solidifying agent and a preparation method thereof. The solidifying agent has good adaptability and can be applied to tailings and waste rocks of different properties, meet the filling needs in a variety of mining environments, and adapt to the requirements of different mine filling processes.

[0038] 5. The present invention proposes an environmentally friendly solidifying agent for mine filling and a preparation method thereof. By optimizing the formula and process, after the solidifying agent is mixed with the tailings slurry, it can quickly coagulate and harden in a short time, the early strength develops rapidly, and the final strength is relatively high. This rapid coagulation and hardening property of the solidifying agent and the tailings slurry can make the tailings slurry form a consolidated body with a certain strength in a short time, which can effectively reduce the floor space of the tailings pond and reduce the potential safety hazards of the tailings pond. After the solidifying agent is mixed with the tailings slurry, the consolidated body formed has good stability, can effectively prevent the loss and dispersion of tailings, and reduce pollution to the environment. The consolidated body formed after the solidifying agent is mixed with the tailings slurry has high strength and stability, can be used as a mine filling material, meet the strength requirements of mine filling, and ensure the safety and stability of the mine.

[0039] 6. The environmentally friendly curing agent for mine filling and its preparation method proposed in the present invention adopt a gradient mixing process, including premixing, strong stirring and homogenization treatment steps, to ensure the full and uniform mixing of the raw materials, and significantly improve the quality stability and performance of the curing agent. By combining primary homogenization and deep homogenization in the homogenization process, as well as the dynamic compost turning process and environmental parameter monitoring and adjustment during the aging process, the preparation process of the curing agent is further optimized, and the production efficiency and product quality are improved. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] An environmentally friendly curing agent for mine filling, the composition and mass fraction of the curing agent are:

[0043] 30 parts of cement clinker, 10 parts of slag powder, 5 parts of fly ash, 3 parts of gypsum, 1 part of active activator, 0.5 parts of admixture, including:

[0044] The active stimulant is a base stimulant;

[0045] The specific surface area of ​​slag powder is greater than 400m² / kg. 2 O 3 Content ≤1.5%;

[0046] Fly ash is Grade II, with loss on ignition ≤8%;

[0047] The gypsum is natural gypsum with a calcium sulfate dihydrate content of ≥85%.

[0048] The alkaline activator is a mixture of sodium hydroxide and water glass, with a purity of ≥95%.

[0049] The admixtures include 0.2% polycarboxylate water reducing agent, 0.1% hydroxypropyl methylcellulose water retaining agent, and 0.2% calcium formate early strength agent. The amount of the admixture added is 0.5% of the total weight of the curing agent.

[0050] Cement clinker is silicate cement clinker. C 3 S content ≥50%, f-CaO ≤1.2%, gypsum dosage controls SO 3 Content: 2.8%.

[0051] The preparation process and use method of environmentally friendly mine filling curing agent are as follows:

[0052] S1. Grind slag powder and cement clinker separately to a specific surface area ≥ 380m² / kg;

[0053] S2, using gradient mixing process:

[0054] a. Premix the ground cement clinker and slag powder in proportion at 400r / min for 6min. During the premixing process, intermittent pulse stirring is adopted, and high-speed stirring is performed for 10 seconds every 2min to promote the initial uniform distribution of the raw materials;

[0055] b. Add fly ash, gypsum and active activator in proportion, stir vigorously at 750r / min for 15min under nitrogen protection, introduce a certain amount of water vapor during the strong stirring process, and control the humidity at 30%; among which, the fineness modulus of fly ash is 2.0, the water requirement ratio is ≤95%, and gypsum needs to be pre-dried before mixing, and its moisture content is controlled to be ≤5%;

[0056] c. Add admixtures and continue to mix evenly, then homogenize the mixed materials;

[0057] S3, aging the homogenized material for 24 hours at a relative humidity of ≤35% and a temperature of 20° C. to obtain a curing agent with a filling effect of the present invention;

[0058] S4. Add the curing agent product obtained in the third step directly into the tailings slurry at a ratio of 15% of the dry tailings in the tailings slurry, and stir for 2 minutes. Then, input it into the mine where filling is required through a pipeline. The tailings slurry filled there will begin to expand, fill the space to be filled, and begin to solidify. After 1 day, the compressive strength of the filling body can reach more than 0.5MPa, and after 3 days, the compressive strength can reach more than 1.0MPa. After 28 days, the compressive strength is 1.8MPa, and there is no obvious joint seam at the top joint part.

[0059] In this embodiment, the grinding in step 1 adopts a closed-circuit grinding system of a roller press combined with a ball mill, and 0.05% of triethanolamine is added as a grinding aid.

[0060] In step 2b, the nitrogen protection oxygen content is ≤5%, and the temperature during the stirring process is controlled at 40°C.

[0061] The aging process in step three adopts a dynamic compost turning process, with the compost being turned once every 8 hours and the pile height not exceeding 1.5m. During the aging process, the temperature and humidity of the material are regularly monitored, and the environmental parameters are adjusted in a timely manner according to the monitoring data.

[0062] In step 2c, the homogenization process is divided into two steps: primary homogenization and deep homogenization:

[0063] a. Primary homogenization: Use a double-shaft screw homogenizer at a working pressure of 0.2MPa for 30 minutes;

[0064] The speed gradient of the dual-axis screw is controlled as follows: 20r / min in the first 15min, and then increased to 35r / min in the later stage;

[0065] The material temperature is controlled at 40°C by jacket cooling;

[0066] b. Deep homogenization: The material after primary homogenization is transported to a continuous homogenization bin and treated for 24 hours under gas fluidization with an air flow velocity of 0.8 m / s;

[0067] The continuous homogenization bin is divided into three temperature control zones, which are: Zone I: 50°C hot air activation, residence time 8h; Zone II: 35°C constant temperature aging, residence time 10h; Zone III: 25°C cooling stabilization, residence time 6h;

[0068] The wind speed ratio of each zone is controlled at Ⅰ:Ⅱ:Ⅲ=1.5:1:0.8.

[0069] Example 2

[0070] An environmentally friendly curing agent for mine filling, the composition and mass fraction of the curing agent are:

[0071] 50 parts of cement clinker, 20 parts of slag powder, 15 parts of fly ash, 8 parts of gypsum, 5 parts of active activator, 2 parts of admixture, including:

[0072] The active stimulant is a sulfate stimulant;

[0073] The specific surface area of ​​slag powder is greater than 400m² / kg. 2 O 3 Content ≤1.5%;

[0074] The fly ash is Grade III fly ash, with a loss on ignition of ≤8%;

[0075] The gypsum is phosphogypsum, and the content of calcium sulfate dihydrate is ≥85%.

[0076] The sulfate activator is sodium sulfate.

[0077] The admixtures include 0.8% polycarboxylate water reducing agent, 0.5% hydroxypropyl methylcellulose water retaining agent, and 0.7% calcium formate early strength agent. The amount of the admixture added is 2% of the total weight of the curing agent.

[0078] Cement clinker is silicate cement clinker. C 3 S content ≥50%, f-CaO ≤1.2%, gypsum dosage controls SO 3 Content: 3.5%.

[0079] The preparation process and use method of environmentally friendly mine filling curing agent are as follows:

[0080] S1. Grind slag powder and cement clinker separately to a specific surface area ≥ 380m² / kg;

[0081] S2, using gradient mixing process:

[0082] a. Premix the ground cement clinker and slag powder in proportion at 600r / min for 8min. During the premixing process, intermittent pulse stirring is adopted, and high-speed stirring is performed for 15 seconds every 2min to promote the initial uniform distribution of the raw materials;

[0083] b. Add fly ash, gypsum and active activator in proportion, stir vigorously at 900r / min for 20min under nitrogen protection, introduce a certain amount of water vapor during the strong stirring process, and control the humidity at 50%; among them, the fineness modulus of fly ash is 3.0, the water requirement ratio is ≤95%, and the gypsum needs to be pre-dried before mixing, and its moisture content is controlled to be ≤5%;

[0084] c. Add admixtures and continue to mix evenly, then homogenize the mixed materials;

[0085] S3, aging the homogenized material for 72 hours at a relative humidity of ≤35% and a temperature of 30° C. to obtain a curing agent with a filling function according to the present invention;

[0086] S4. Add the curing agent product obtained in the third step directly into the tailings slurry at a ratio of 10% of the dry tailings in the tailings slurry, and stir for 2 minutes. Then, input it into the mine where filling is required through a pipeline. The tailings slurry filled there will begin to expand, fill the space to be filled, and begin to solidify. After 1 day, the compressive strength of the filling body can reach more than 0.4MPa, and after 3 days, the compressive strength can reach more than 0.8MPa. After 28 days, the compressive strength is 2.0MPa, and there is no obvious joint seam at the top joint part.

[0087] In this embodiment, the grinding in step 1 adopts a closed-circuit grinding system of a roller press combined with a ball mill, and 0.15% of triethanolamine is added as a grinding aid.

[0088] In step 2b, the nitrogen protection oxygen content is ≤5%, and the temperature during the stirring process is controlled at 60°C.

[0089] The aging process in step three adopts a dynamic compost turning process, with the compost being turned once every 8 hours and the pile height not exceeding 1.5m. During the aging process, the temperature and humidity of the material are regularly monitored, and the environmental parameters are adjusted in a timely manner according to the monitoring data.

[0090] In step 2c, the homogenization process is divided into two steps: primary homogenization and deep homogenization:

[0091] a. Primary homogenization: Use a double-shaft screw homogenizer at a working pressure of 0.4 MPa for 45 minutes;

[0092] The speed gradient of the dual-axis screw was controlled as follows: 30r / min in the first 15min and then increased to 45r / min in the later stage;

[0093] The material temperature is controlled at 50°C by jacket cooling;

[0094] b. Deep homogenization: The material after primary homogenization is transported to a continuous homogenization bin and treated continuously for 48 hours under gas fluidization with an air flow velocity of 1.2 m / s;

[0095] The continuous homogenization bin is divided into three temperature control zones, which are: Zone I: 60°C hot air activation, residence time 12h; Zone II: 45°C constant temperature aging, residence time 14h; Zone III: 30°C cooling stabilization, residence time 10h;

[0096] The wind speed ratio of each zone is controlled at Ⅰ:Ⅱ:Ⅲ=1.5:1:0.8.

[0097] Example 3

[0098] An environmentally friendly curing agent for mine filling, the composition and mass fraction of the curing agent are:

[0099] 40 parts of cement clinker, 15 parts of slag powder, 10 parts of fly ash, 5 parts of gypsum, 3 parts of active activator, 1 part of admixture, including:

[0100] The active stimulant is a compound of an alkali stimulant and a sulfate stimulant, with a weight ratio of 1:0.6;

[0101] The specific surface area of ​​slag powder is greater than 400m² / kg. 2 O 3 Content ≤1.5%;

[0102] The fly ash is Grade III fly ash, with a loss on ignition of ≤8%;

[0103] The gypsum is desulfurized gypsum, and the content of calcium sulfate dihydrate is ≥85%.

[0104] The alkaline activator is a mixture of sodium hydroxide and water glass with a purity of ≥95%, and the sulfate activator is potassium sulfoaluminate.

[0105] The admixtures include 0.5% polycarboxylate water reducing agent, 0.3% hydroxypropyl methylcellulose water retaining agent, and 0.4% calcium formate early strength agent. The amount of the admixture added is 1% of the total weight of the curing agent.

[0106] Cement clinker is silicate cement clinker. C 3 S content ≥50%, f-CaO ≤1.2%, gypsum dosage controls SO 3 Content: 3.1%.

[0107] The preparation process and use method of environmentally friendly mine filling curing agent are as follows:

[0108] S1. Grind slag powder and cement clinker separately to a specific surface area ≥ 380m² / kg;

[0109] S2, using gradient mixing process:

[0110] a. Premix the ground cement clinker and slag powder in proportion at 500r / min for 6min. During the premixing process, intermittent pulse stirring is adopted, and high-speed stirring is performed for 12 seconds every 2min to promote the initial uniform distribution of the raw materials;

[0111] b. Add fly ash, gypsum and active activator in proportion, stir vigorously at 800r / min for 18min under nitrogen protection, introduce a certain amount of water vapor during the strong stirring process, and control the humidity at 40%; among them, the fineness modulus of fly ash is 2.5, the water requirement ratio is ≤95%, and the gypsum needs to be pre-dried before mixing, and its moisture content is controlled to be ≤5%;

[0112] c. Add admixtures and continue to mix evenly, then homogenize the mixed materials;

[0113] S3, aging the homogenized material for 48 hours at a relative humidity of ≤35% and a temperature of 25° C. to obtain a curing agent with a filling effect of the present invention;

[0114] S4. Add the curing agent product obtained in the third step directly into the tailings slurry at a ratio of 13% of the dry tailings in the tailings slurry, and stir for 2 minutes. Then, input it into the mine where filling is required through a pipeline. The tailings slurry filled there will begin to expand, fill the space to be filled, and begin to solidify. After 1 day, the compressive strength of the filling body can reach more than 0.6MPa, and after 3 days, the compressive strength can reach more than 1.2MPa. After 28 days, the compressive strength is 2.2MPa, and there is no obvious joint seam at the top joint part.

[0115] In this embodiment, the grinding in step 1 adopts a closed-circuit grinding system of a roller press combined with a ball mill, and 0.1% triethanolamine is added as a grinding aid.

[0116] In step 2b, the nitrogen protection oxygen content is ≤5%, and the temperature during the stirring process is controlled at 50°C.

[0117] The aging process in step three adopts a dynamic compost turning process, with the compost being turned once every 8 hours and the pile height not exceeding 1.5m. During the aging process, the temperature and humidity of the material are regularly monitored, and the environmental parameters are adjusted in a timely manner according to the monitoring data.

[0118] In step 2c, the homogenization process is divided into two steps: primary homogenization and deep homogenization:

[0119] a. Primary homogenization: using a double-shaft screw homogenizer at a working pressure of 0.3 MPa for 37 minutes;

[0120] The speed gradient of the dual-axis screw is controlled as follows: 25r / min in the first 15min, and then increased to 40r / min in the later stage;

[0121] The material temperature is controlled at 45°C by jacket cooling;

[0122] b. Deep homogenization: The material after primary homogenization is transported to a continuous homogenization bin and treated for 36 hours under gas fluidization with an air flow velocity of 1 m / s;

[0123] The continuous homogenization bin is divided into three temperature control zones, which are: Zone I: 55°C hot air activation, residence time 10h; Zone II: 40°C constant temperature aging, residence time 12h; Zone III: 28°C cooling stabilization, residence time 8h;

[0124] The wind speed ratio of each zone is controlled at Ⅰ:Ⅱ:Ⅲ=1.5:1:0.8.

[0125] Comparative Example 1

[0126] Compared with Example 1, Comparative Example 1 directly uses ordinary Portland cement without adding slag powder, fly ash and active activator. All raw materials are mixed conventionally without gradient mixing, nitrogen protection and water vapor adjustment, and without homogenization treatment. The raw materials are directly used after mixing. The amount of curing agent added is 25% of the mass of the dry tailings, and the remaining steps are exactly the same as those in Example 1.

[0127] Comparative Example 2

[0128] Compared with Example 2, in Comparative Example 2, only sodium sulfate is used as the active stimulant, the mixture is directly exposed to air for stirring, only primary homogenization is performed for the homogenization treatment, the aging condition is static stacking at room temperature, and the remaining steps are exactly the same as in Example 2.

[0129] Comparative Example 3

[0130] Compared with Example 3, all the raw materials were mixed at one time, water vapor was not introduced to adjust the humidity, the stirring temperature was increased to 80°C, the homogenization treatment only adopted single-stage spiral homogenization, there was no continuous homogenization bin, the aging time was shortened to 24h, there was no dynamic compost turning, and the other steps were exactly the same as in Example 3.

[0131] The comparative analysis results of the test data of each implementation method are shown in Table 1 below:

[0132] Table 1: Comparative analysis of test data of various implementation methods

[0133] index Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 1 day strength (MPa) ≥0.5 ≥0.4 ≥0.6 ≤0.2 0.3-0.4 0.2-0.3 28-day strength (MPa) 1.8 2.0 2.2 1.0-1.2 1.5-1.6 1.3-1.4 Curing agent dosage 15% 10% 13% 25% 13% 10% Filling rate ≥95% ≥95% ≥95% 70-80% 85% 80% Cost Comparison -40% -35% -38% Benchmarks -20% -25%

[0134] In practical applications, the curing agent of the above-mentioned embodiments 1-3 is mixed evenly with an appropriate amount of water and tailings, waste rock, etc., and then pumped to the mine for filling. According to tests, the filling body using the curing agent of the present invention can reach a high strength within 24 hours, meeting the requirements of mine support, and the curing time is shortened by about 30% compared with traditional cement filling, and the cost is reduced by about 40%.

[0135] The above descriptions are only some preferred embodiments of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the embodiments of the present disclosure.

Claims

1. An environmentally friendly curing agent for mine filling, characterized in that: The composition and mass fraction of the curing agent are: 30-50 parts of cement clinker, 10-20 parts of slag powder, 5-15 parts of fly ash, 3-8 parts of gypsum, 1-5 parts of active activator, 0.5-2 parts of admixture, including: The active stimulant is a compound of an alkali stimulant and a sulfate stimulant, and can also be one of an alkali stimulant or a sulfate stimulant; The admixture includes one or more of a water reducing agent, an early strength agent, and a water retaining agent, and the amount of the admixture added is 0.5%-2% of the total weight of the curing agent; The specific surface area of ​​the slag powder is greater than 400m² / kg, and the Fe2O3 content after magnetic separation is ≤1.5%; The fly ash is Grade II or Grade III fly ash, with a loss on ignition of ≤8%; The gypsum is natural gypsum or industrial by-product gypsum, and the content of calcium sulfate dihydrate is ≥85%.

2. The environmentally friendly mine filling curing agent according to claim 1, characterized in that: The alkaline activator is a mixture of sodium hydroxide and water glass with a purity of ≥95%, and the sulfate activator is sodium sulfate or potassium sulfoaluminate.

3. The environmentally friendly curing agent for mine filling according to claim 2, characterized in that: The admixtures include 0.2-0.8% polycarboxylate water reducing agent, 0.1-0.5% hydroxypropyl methylcellulose water retaining agent, and 0.2-0.7% calcium formate early strength agent, and the total addition amount does not exceed 2% of the mass of the curing agent.

4. The environmentally friendly curing agent for mine filling according to claim 3, characterized in that: The cement clinker is silicate cement clinker, in which the C3S content is ≥50%, f-CaO is ≤1.2%, and the gypsum content is controlled to control the SO3 content to 2.8-3.5%.

5. A method for preparing an environmentally friendly mine filling curing agent as claimed in claim 1, characterized in that: The steps include: S1. Grind slag powder and cement clinker separately to a specific surface area ≥ 380m² / kg; S2, using gradient mixing process: a. Premix the ground cement clinker and slag powder in proportion at 400-600r / min for 5-8min. During the premixing process, intermittent pulse stirring is adopted, and high-speed stirring is performed for 10-15 seconds every 2min to promote the initial uniform distribution of the raw materials; b. Add fly ash, gypsum and active activator in proportion, stir vigorously at 750-900r / min for 15-20min under nitrogen protection, and introduce a certain amount of water vapor during the strong stirring process, and control the humidity at 30%-50%; among which, the fineness modulus of fly ash is 2.0-3.0, the water requirement ratio is ≤95%, and the gypsum needs to be pre-dried before mixing, and its moisture content is controlled to be ≤5%; c. Add admixtures and continue to mix evenly, then homogenize the mixed materials; S3. The homogenized material is aged for 24-72 hours at a relative humidity of ≤35% and a temperature of 20-30°C.

6. The method for preparing an environmentally friendly mine filling curing agent according to claim 5, characterized in that: In the step 1, the grinding is carried out using a closed-circuit grinding system of a roller press combined with a ball mill, and 0.05-0.15% of triethanolamine as a grinding aid is added.

7. The method for preparing an environmentally friendly mine filling curing agent according to claim 5, characterized in that: In step 2b, the nitrogen protection oxygen content is ≤5%, and the temperature during the stirring process is controlled at 40-60°C.

8. The method for preparing an environmentally friendly mine filling curing agent according to claim 5, characterized in that: The aging process in step 3 adopts a dynamic compost turning process, with the compost being turned once every 8 hours and the pile height not exceeding 1.5 m. During the aging process, the temperature and humidity of the material are regularly monitored, and the environmental parameters are adjusted in a timely manner according to the monitoring data.

9. The method for preparing an environmentally friendly mine filling curing agent according to claim 5, characterized in that: The homogenization process in step 2c is carried out in two steps: primary homogenization and deep homogenization. a. Primary homogenization: Use a double-shaft spiral homogenizer at a working pressure of 0.2-0.4MPa for 30-45min; The speed gradient of the dual-axis spiral is controlled as follows: 20-30r / min in the first 15min, and then increased to 35-45r / min in the later stage; The material temperature is controlled at 40-50°C by jacket cooling; b. Deep homogenization: The material after primary homogenization is transported to a continuous homogenization bin and treated continuously for 24-48 hours under gas fluidization with an air flow velocity of 0.8-1.2 m / s; The continuous homogenization bin is divided into three temperature control zones, which are: Zone I: 50-60℃ hot air activation, residence time 8-12h; Zone II: 35-45℃ constant temperature aging, residence time 10-14h; Zone III: 25-30℃ cooling stabilization, residence time 6-10h; The wind speed ratio of each zone is controlled at Ⅰ:Ⅱ:Ⅲ=1.5:1:0.8.