Phosphorus-doped gypsum-based filling material and preparation method thereof

Abstract

The invention belongs to the technical field of mine filling materials, and discloses an ardealite-doped filling material and a preparation method thereof, the filling material comprises the following components by weight: 8-12% of cement, 40-87% of ardealite, 10-20% of fly ash, and 20-30% of phosphate tailings; wherein a modifier and CaO are added into the ardealite, and the weight of the modifier is 0.5-1% of the weight of the ardealite; the weight of the CaO is 0.5-1% of the weight of the phosphogypsum; the ardealite and the phosphate tailings are used for producing the filling material, so that the problem of stockpiling of two solid wastes is solved; the curing treatment cost of the filling material is reduced, and meanwhile, the phosphogypsum and the phosphate tailings are subjected to innocent treatment, so that the pollution to the environment is reduced; in addition, the filling material is good in performance, large in compressive strength and suitable for filling the goaf of the mine.

Description

Technical Field

[0001] The present invention relates to the technical field of mine filling materials, and particularly to a filling material based on doped phosphogypsum and a preparation method thereof. Background Art

[0002] A large amount of solid waste phosphogypsum is generated during the production of industrial wet-process phosphoric acid by decomposing phosphate rock with sulfuric acid. The main chemical components are gypsum, a small amount of phosphorus pentoxide and trace fluorine. The output of phosphogypsum in China is large, about 80 million tons are newly added every year, and the stockpile has exceeded 700 million tons. Moreover, the comprehensive utilization degree of phosphogypsum in China is low, lacking effective disposal channels, and most of them are stacked for treatment. In addition, most of the currently mined phosphate ores have low grades and need beneficiation. For every 1t of phosphate concentrate produced, 0.44t of phosphate tailings will be generated. Phosphate tailings exist in large quantities in the tailings pond as waste from phosphate ore beneficiation. The stacking of phosphogypsum and phosphate tailings occupies a large amount of limited land, and there is a potential pollution risk to the environment. The harmful soluble substances, elements and residual flotation agents in phosphate tailings, as well as the impurities such as strong acids, phosphorus and fluorine in phosphogypsum, will undergo complex chemical migration under the long-term action of natural precipitation, thus polluting the atmosphere, water and soil, and seriously endangering the surrounding environment. In addition, the tailings pond and the goaf generated by mining also bring huge potential safety hazards. Therefore, the resource utilization of phosphate tailings has become an important task that major phosphate ore enterprises urgently need to carry out. At present, the resource utilization of phosphate tailings mainly focuses on fields such as construction, agriculture, ceramsite and flame retardancy. However, the utilization rate of phosphate tailings is still very low, and there is an urgent need to explore a new and promising method for the utilization of phosphate tailings.

[0003] The filling mining method is an advanced and applicable technology for safe production vigorously promoted by the state. This method can make extensive use of various solid wastes, effectively solve the problem of surface stacking of wastes, and has a high resource recovery rate. It can effectively manage ground pressure and ensure the safety of underground operations. Using the tailings cemented filling technology for underground filling is currently the most effective method to solve the above problems.

[0004] However, in traditional tailings consolidated filling technology, cement is generally used as a cementing material to solidify and cement tailings, but the filling cost is relatively high and the strength of the consolidated body is relatively low. At present, there is very little research on the performance of consolidating phosphate tailings with phosphogypsum-based cementing materials, and the doping amount of phosphogypsum is extremely small or it is only used as an inert filling aggregate. The cementing material for solidifying tailings is still cement or slag, and the filling cost is still relatively high and the strength of the consolidated body is relatively low. In addition, using phosphogypsum-based cementing materials to consolidate phosphate tailings often does not involve the harmless treatment of phosphogypsum and the environmental protection effect of filling. Summary of the Invention

[0005] The present invention aims to provide a filling material based on phosphorus gypsum and a preparation method thereof, which uses phosphorus gypsum and phosphorus tailings to produce the filling material, solves the problem of the storage of the two solid wastes; reduces the solidification treatment cost of the filling material, and at the same time harmlessly treats the phosphorus gypsum and phosphorus tailings, reducing environmental pollution; in addition, the filling material has good performance and high compressive strength, and is suitable for filling the goaf in mines. The problems in the background art are solved.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A filling material based on phosphorus gypsum, by weight percentage, the filling material includes: by weight percentage, the filling material includes: 8-12% of cement, 40-87% of phosphorus gypsum, 10-20% of fly ash, and 20-30% of phosphorus tailings; wherein, a modifier and CaO are added to the phosphorus gypsum, the weight of the modifier is 0.5-1% of the weight of the phosphorus gypsum; the weight of CaO is 0.5-1% of the weight of the phosphorus gypsum.

[0008] Further, the phosphorus tailings include coarse aggregate or fine aggregate.

[0009] Further, by weight percentage, the filling material includes: 12% of cement, 48% of phosphorus gypsum, 20% of fly ash, and 20% of fine aggregate.

[0010] Further, the phosphorus tailings include coarse aggregate and fine aggregate, and the mass ratio of the coarse aggregate to the fine aggregate is 1:2-3.

[0011] Further, by weight percentage, the filling material includes: 12% of cement, 48% of phosphorus gypsum, 20% of fly ash, 5% of coarse aggregate, and 15% of fine aggregate.

[0012] Further, by weight percentage, the modifier includes: 20%-30% polyacrylic acid emulsion, 25%-45% nano-silica, 25%-45% nano-alumina, and 30% sodium methyl silicate.

[0013] According to the above-mentioned preparation method of a filling material based on phosphorus gypsum, it includes the following steps:

[0014] S1. Weigh cement, phosphorus gypsum, fly ash and phosphorus tailings in the ratio of 8-12%: 40-87%: 10-20%: 20-30%;

[0015] S2. Add the modifier and CaO to the phosphorus gypsum, add water and stir evenly to obtain a slurry, and let it stand for standby;

[0016] S3. Add the weighed cement, fly ash, coarse aggregate, and phosphorus tailings to the slurry obtained in step S2, add water, and stir evenly to obtain a filling material; the water content of the filling material is 10-30%.

[0017] The principle and beneficial effects of the technical solution are as follows:

[0018] A filling material based on phosphorus gypsum admixture and its preparation method provided by the present invention use industrial waste phosphorus gypsum and phosphorus tailings as the main raw materials, realize the resource utilization of solid waste, improve its comprehensive utilization rate, have a simple production process, low energy consumption, low production cost, and are low-carbon, environmentally friendly, green and harmless; the prepared filling material has good performance and relatively high compressive strength. Specifically, the modifier pre-treats the phosphorus gypsum. The modifier is an inorganic-polymer composite nanomaterial, which harmlessly treats solid wastes such as phosphorus gypsum. The surface of the phosphorus gypsum particles changes from hydrophilic to hydrophobic, and the fluidity of the filling paste after natural molding is good, which can effectively solve the strength reduction caused by the softening of traditional filling materials due to water erosion; and the nanoemulsion in the modifier is aimed at solid waste filling cementitious materials such as phosphorus gypsum, reacts with harmful elements in the phosphorus gypsum to form special stable precipitates, solidifies and adsorbs harmful elements, effectively preventing the leakage of harmful elements and reducing environmental pollution; and the modifier has a small mixing ratio, a short curing time, and forms a hardened body with a certain strength under the action of natural pressure, meeting the needs of mine filling; in addition, the particle size of phosphorus gypsum is extremely fine, and particles below 0.1 mm account for 93%. This ultra-fine material is not conducive to filling dehydration and rapid hardening. Especially, CaSO4·2H2O in phosphorus gypsum has a retarding property, which inhibits the early cementation of the cemented filling body. The fly ash has a high SiO2 content of up to 52% and an Al2O3 content of over 21%, having potential cementing properties and being beneficial to the strength of the filling body; phosphorus gypsum is an acidic substance (pH = 2-3), and fly ash is an alkaline substance (pH value 9-11), and the two can undergo a neutralization reaction; in addition, phosphorus gypsum and fly ash belong to the clay category and are easy to mix during pulping, which is beneficial to reducing the segregation of cement. Specific embodiments

[0019] The present invention will be further described in detail below in conjunction with the embodiments:

[0020] Example 1

[0021] A filling material based on phosphorus gypsum. By weight percentage, the filling material includes: 12% cement, 48% phosphorus gypsum, 20% fly ash, and 20% fine aggregate. Among them, a modifier and CaO are added to the phosphorus gypsum. The weight of the modifier is 0.5% of the weight of the phosphorus gypsum; the weight of CaO is 0.5% of the weight of the phosphorus gypsum. Among them, the modifier by weight percentage is: 20% polyacrylic acid emulsion, 25% nano-silica, 25% nano-aluminum oxide, and 30% sodium methyl silicate. The cement is one or several of PO.425 (cement with a strength grade of 42.5 MPa), PO.325 (cement with a strength grade of 32.5 MPa), and cement clinker. In this example, the following examples and comparative examples all use PO.425. The fine aggregate is flotation tailings, which are the tailings remaining after processing the ore by the flotation method (using the differences in the physicochemical properties of the mineral surface to separate useful minerals by bubble flotation). The coarse aggregate is gravity separation tailings, which are the tailings remaining after processing the ore by the gravity separation method (using the density difference of minerals to separate by gravity or centrifugal force).

[0022] The preparation method is as follows:

[0023] S1. Weigh 12% cement, 48% phosphorus gypsum, 20% fly ash, and 20% fine aggregate by mass percentage;

[0024] S2. Add 0.5% modifier and 0.5% CaO to the phosphorus gypsum, add water for pretreatment, stir evenly with a stirrer to obtain a slurry, and let it stand for later use;

[0025] S3. Add the weighed cement, fly ash, coarse aggregate, and phosphorus tailings to the slurry obtained in step S2, add water, stir and mix evenly to obtain the filling material, and the water content of this filling material is 20%; then inject it into a test mold of 7.07 cm × 7.07 cm × 7.07 cm, demold after natural curing for 48 h, and measure the uniaxial compressive strength of the test blocks at different ages according to the regulations in the "Standard Test Method for Properties of Ordinary Concrete Mixtures".

[0026] The experimental results of the compressive strength of the above materials are as follows: the 7-day compressive strength is 0.296 MPa, the 14-day compressive strength is 0.825 MPa, and the 28-day compressive strength is 1.257 MPa.

[0027] Perform a toxicity leaching test on the filling body specimen cured to 28 d. The leaching values in the filling body specimens did not change the background groundwater standard level "Groundwater Quality Standard" (GB / T 14848-2017). It can be seen from the test report that the total fluorine content is reduced to 2.05 mg / L; the total phosphorus content is reduced to 0.40 mg / L, and the harmful ions are effectively controlled.

[0028] Example 2

[0029] A filling material based on phosphorus gypsum. By weight percentage, the filling material includes: 12% cement, 48% phosphorus gypsum, 20% fly ash, 15% fine aggregate, and 5% coarse aggregate. Among them, a modifier and CaO are added to the phosphorus gypsum. The weight of the modifier is 0.5% of the weight of the phosphorus gypsum; the weight of CaO is 0.5% of the weight of the phosphorus gypsum. Among them, the modifier by weight percentage is: 20% polyacrylic acid emulsion, 25% nano-silica, 25% nano-alumina, and 30% sodium methyl silicate.

[0030] The preparation method is as follows:

[0031] S1. Weigh 12% cement, 48% phosphorus gypsum, 20% fly ash, 15% fine aggregate, and 5% coarse aggregate by mass percentage.

[0032] S2. Add 0.5% modifier and 0.5% CaO to the phosphorus gypsum, add water for pretreatment, and stir evenly with a mixer to obtain a slurry, then let it stand for later use. Among them, the modifier by weight percentage is: 20% polyacrylic acid emulsion, 25% nano-silica, 25% nano-alumina, and 30% sodium methyl silicate.

[0033] S3. Add the weighed cement, fly ash, coarse aggregate, and phosphorus tailings to the slurry obtained in step S2, add water, stir and mix evenly to obtain the filling material, and the water content of this filling material is 20%. Then inject it into a test mold of 7.07 cm × 7.07 cm × 7.07 cm, demold after natural curing for 48 h, and measure the uniaxial compressive strength of the test block at different ages according to the regulations in the "Standard Test Method for Properties of Ordinary Concrete Mixtures".

[0034] The experimental results of the compressive strength of the above materials are as follows: the 7-day compressive strength is 0.343 MPa, the 14-day compressive strength is 0.674 MPa, and the 28-day compressive strength is 1.113 MPa.

[0035] Perform a toxicity leaching test on the filling body specimen cured to 28 d. The leaching values in the filling body specimens have not changed the background groundwater standard level "Groundwater Quality Standard" (GB / T 14848 - 2017). It can be seen from the test report that the total fluorine content is reduced to 3.42 mg / L; the total phosphorus content is reduced to 0.37 mg / L, and the harmful ions are effectively controlled, indicating that the modifier has a certain solidification effect on harmful ions such as phosphorus and fluorine. Since the fine aggregate is the tailings left over from phosphorus ore flotation, its harmful ion content is more than that of phosphorus gypsum. Therefore, after adding the modifier, the total phosphorus content has not changed much, but the total fluorine content has decreased significantly compared with the sample without the modifier, indicating that the modifier has a certain solidification effect on harmful ions such as phosphorus and fluorine.

[0036] From the experimental results of Example 1 and Example 2, it can be seen that a filling material based on phosphorus gypsum and its preparation method provided by the present invention uses industrial waste phosphorus gypsum and phosphorus tailings as the main raw materials, realizes the resource utilization of solid waste, improves its comprehensive utilization rate, has a simple production process, low energy consumption, and low production cost; in the modifier, the nano-emulsion targets solid waste filling cementitious materials such as phosphorus gypsum, reacts with harmful elements in phosphorus gypsum to form special stable precipitates, solidifies and adsorbs harmful elements, effectively prevents the leakage of harmful elements, and reduces environmental pollution; in addition, the particle size of phosphorus gypsum is extremely fine, which is not conducive to filling dehydration and rapid hardening. Fly ash has potential cementitious properties, which is beneficial to increasing the strength of the filling body. The modifier has a small mixing ratio, a short curing time, and forms a hardened body with a certain strength under the action of natural pressure. In addition, phosphorus gypsum and fly ash belong to the clay category and are easy to mix during pulping, which is beneficial to reducing the segregation of cement. Therefore, the prepared filling material has good performance and a large compressive strength, and can meet the needs of mine filling.

[0037] Control Example 1

[0038] In this control example, the combination of each component is measured by mass percentage. First, 82% of phosphorus gypsum is weighed, 0.5% (0.5% of the mass of phosphorus gypsum) of the modifier and 0.5% (0.5% of the mass of phosphorus gypsum) of CaO are added, and a certain amount of water is added for pretreatment of phosphorus gypsum, and it is stirred evenly with a stirrer. Then, 8% of cement as the cementitious material and 10% of fly ash are added, and water is added. The water content of this sample is 25%. After stirring and mixing evenly, a slurry-like filling material is obtained. Then, it is poured into a test mold of 7.07 cm × 7.07 cm × 7.07 cm, and the mold is removed after natural curing for 48 h. The uniaxial compressive strength of the test block at different ages is measured according to the regulations in the "Standard for Test Methods of Performance of Ordinary Concrete Mixtures". Among them, the modifier is calculated by weight percentage as: 20% polyacrylic acid emulsion, 25% nano-silica, 25% nano-alumina, and 30% sodium methyl silicate.

[0039] The experimental results of the compressive strength of the above materials are as follows: the 7-day compressive strength is 0.261 MPa, the 14-day compressive strength is 0.302 MPa, and the 28-day compressive strength is 0.926 MPa.

[0040] The ratios of cement, phosphorus gypsum, and fly ash are changed to obtain different filling materials, which are placed for 7 days, 14 days, and 28 days respectively, and the compressive strengths of the filling materials with different ratios are measured, as shown in Table 1 below:

[0041] Table 1 Compressive strengths of filling materials with different raw material ratios after being placed for 7 days, 14 days, and 28 days

[0042]

[0043] The specimens of the filling bodies (serial numbers 1-4) cured for 28 days were subjected to a toxicity leaching test. The leaching values in the filling body specimens did not change the background groundwater standard level of "Groundwater Quality Standard" (GB / T 14848-2017). From the test report, it can be seen that the total fluorine content decreased from 12.5 mg / L to 1.16 mg / L; the total phosphorus content decreased from 1.42 mg / L to 0.20 mg / L, and the harmful ions were effectively controlled. The other heavy metal elements were all lower than the specified values in the "Groundwater Quality Standard", indicating that the modifier has a certain solidification effect on harmful ions such as phosphorus and fluorine.

[0044] Comparative Example 2

[0045] In this comparative example, the combinations of each component are measured in mass percentages. First, 71% of phosphogypsum was weighed, 1% (1% of the mass of phosphogypsum) of the modifier and 1% (1% of the mass of phosphogypsum) of CaO were added, and a certain amount of water was added to pretreat the phosphogypsum. It was stirred evenly with a stirrer. Then, 3.5% of cement as the gelling material and 22.8% of fly ash were added, and water was added. The water content of this sample was 25%. After stirring and mixing evenly, a paste-like filling material was obtained. Then, it was poured into a mold of 7.07 cm × 7.07 cm × 7.07 cm. After natural curing for 48 h, the mold was removed, and the uniaxial compressive strength of the test blocks at different ages was measured according to the regulations in the "Standard Test Method for Properties of Ordinary Concrete Mixtures". Among them, the modifier is calculated by weight percentage as: 20% polyacrylic acid emulsion, 25% nano-silica, 25% nano-aluminum oxide, and 30% sodium methyl silicate.

[0046] The experimental results of the compressive strength of the above materials are as follows: the 7-day compressive strength is 0.714 MPa, the 14-day compressive strength is 1.01 MPa, and the 28-day compressive strength is 1.30 MPa.

[0047] Comparative Example 3

[0048] In this comparative example, the combinations of each component are measured in mass percentages. First, 77% of phosphogypsum was weighed, 0.5% (0.5% of the mass of phosphogypsum) of the modifier and 0.5% (0.5% of the mass of phosphogypsum) of CaO were added, and a certain amount of water was added to pretreat the phosphogypsum. It was stirred evenly with a stirrer. Then, 8% of cement as the gelling material, 5% of coarse aggregate, and 10% of fine aggregate were added, and water was added. The water content of this sample was 30%. After stirring and mixing evenly, a paste-like filling material was obtained. Then, it was poured into a mold of 7.07 cm × 7.07 cm × 7.07 cm. After natural curing for 48 h, the mold was removed, and the uniaxial compressive strength of the test blocks at different ages was measured according to the regulations in the "Standard Test Method for Properties of Ordinary Concrete Mixtures". Among them, the modifier is calculated by weight percentage as: 20% polyacrylic acid emulsion, 25% nano-silica, 25% nano-aluminum oxide, and 30% sodium methyl silicate.

[0049] The experimental results of the compressive strength of the above materials are as follows: the compressive strength at 7 days is 0.343 MPa, the compressive strength at 14 days is 0.408 MPa, and the compressive strength at 28 days is 1.172 MPa.

[0050] By changing the ratios of cement, phosphogypsum, coarse aggregate and fine aggregate and the water content, different filling materials are obtained. After being placed for 7 days, 14 days and 28 days respectively, the compressive strengths of the filling materials with different ratios are measured, as shown in Table 2 below:

[0051] Table 2 Compressive strengths of filling materials with different raw material ratios after being placed for 7 days, 14 days and 28 days respectively

[0052]

[0053] Comparative Example 4

[0054] In this comparative example, the combinations of each component are measured by mass percentage. First, 87% of phosphogypsum is weighed, 0.5% (0.5% of the mass of phosphogypsum) of a modifier and 0.5% (0.5% of the mass of phosphogypsum) of CaO are added, and a certain amount of water is added to pretreat the phosphogypsum. It is stirred evenly with a stirrer. Then, 8% of cement as a gelling material and 5% of coarse aggregate are added, and water is added. The water content of this sample is 18%. After stirring and mixing evenly, a paste-like filling material is obtained. Then it is poured into a mold of 7.07 cm × 7.07 cm × 7.07 cm. After natural curing for 48 h, the mold is removed, and the uniaxial compressive strengths of the test blocks at different ages are measured according to the regulations in the "Standard for Test Methods of Properties of Ordinary Concrete Mixtures". Among them, the modifier is by weight percentage: 20% polyacrylic acid emulsion, 25% nano-silica, 25% nano-aluminum oxide and 30% sodium methyl silicate.

[0055] The experimental results of the compressive strength of the above materials are as follows: the compressive strength at 3 days is 0.212 MPa, the compressive strength at 7 days is 0.44 MPa, the compressive strength at 14 days is 1.335 MPa, and the compressive strength at 28 days is 1.851 MPa.

[0056] By changing the ratios of cement, phosphogypsum and coarse aggregate and the water content, different filling materials are obtained. After being placed for 7 days, 14 days and 28 days respectively, the compressive strengths of the filling materials with different ratios are measured, as shown in Table 3 below:

[0057] Table 3 Compressive strengths of filling materials with different raw material ratios after being placed for 7 days, 14 days and 28 days respectively

[0058]

[0059] Comparative Example 5

[0060] In this comparative example, the combinations of each component are measured by mass percentage. First, 60% of phosphogypsum is weighed, 0.5% (0.5% of the mass of phosphogypsum) of a modifier and 0.5% (0.5% of the mass of phosphogypsum) of CaO are added, and a certain amount of water is added for pre-treatment of phosphogypsum. It is stirred evenly with a stirrer. Then, 10% of cement as a gelling material, 20% of fly ash, and 10% of coarse aggregate are added, and water is added. The water content of this sample is 20%. After stirring and mixing evenly, a paste-like filling material is obtained. Then it is poured into a mold of 7.07 cm×7.07 cm×7.07 cm. After natural curing for 48 h, the mold is removed, and the uniaxial compressive strength of the test block at different ages is measured according to the regulations in the "Standard Test Method for Properties of Ordinary Concrete Mixtures". Among them, the modifier is by weight percentage: 20% polyacrylic acid emulsion, 25% nano-silica, 25% nano-aluminum oxide, and 30% sodium methyl silicate.

[0061] The experimental results of the compressive strength of the above materials are as follows: the 7-day compressive strength is 0.29 MPa, the 14-day compressive strength is 0.529 MPa, and the 28-day compressive strength is 1.384 MPa.

[0062] The ratios of cement, phosphogypsum, coarse aggregate, and fly ash, as well as the water content, are changed to obtain different filling materials, which are placed for 7 days, 14 days, and 28 days respectively. The compressive strengths of the filling materials with different ratios are measured, as shown in Table 4 below:

[0063] Table 4 Compressive strengths of filling materials with different raw material ratios after being placed for 7 days, 14 days, and 28 days

[0064]

[0065] In summary, from the experimental results of Comparative Examples 1 to 5, it can be seen that the modifier is used to pretreat phosphogypsum. The modifier is an inorganic-polymer composite nanomaterial, which can harmlessly treat solid wastes such as phosphogypsum. The surface of phosphogypsum particles changes from hydrophilic to hydrophobic. The formed filling paste after natural shaping has good fluidity, which can effectively solve the strength reduction caused by the softening of traditional filling materials due to water erosion. Moreover, the nanoemulsion in the modifier is aimed at the filling cementitious materials of solid wastes such as phosphogypsum, reacts with harmful elements in phosphogypsum to form special stable precipitates, solidifies and adsorbs harmful elements, effectively preventing the leakage of harmful elements and reducing environmental pollution. In addition, the modifier has a small mixing ratio, a short curing time, and can form a hardened body with a certain strength under the action of natural pressure, meeting the needs of mine filling. In addition, the particle size of phosphogypsum is extremely fine, and particles below 0.1 mm account for 93%. Such ultra-fine materials are not conducive to filling dehydration and rapid hardening. In particular, CaSO4·2H2O in phosphogypsum has a retarding property, which inhibits the early cementation of the cemented filling body. The SiO2 content of fly ash is as high as 52%, and the Al2O3 content is above 21%, which has potential cementing properties and is beneficial to the strength of the filling body. In addition, CaO has multiple functions in the pretreatment. On the one hand, it can adjust the pH value, on the other hand, it can fix phosphorus and fluorine. Moreover, it can be found that compared with phosphogypsum without adding the modifier, the phosphogypsum pretreated with the modifier has higher compressive strength and lower total phosphorus and fluorine contents, indicating the important role of the modifier and its important role in environmental protection.

[0066] The above are only the embodiments of the present invention. Specific technical solutions or common knowledge such as characteristics known in the solutions are not described in detail here. It should be noted that for those skilled in the art, without departing from the technical solution of the present invention, several deformations and improvements can still be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicality of the patent. The protection scope required by this application should be subject to the content of its claims, and the specific implementation manners described in the specification can be used to explain the content of the claims.

Claims

1. A filling material based on phosphorus-containing gypsum, characterized in that, The filling material, by weight percentage, comprises: 8-12% of cement, 40-87% of phosphogypsum, 10-20% of fly ash, and 20-30% of phosphate tailings; wherein, a modifier and CaO are added to the phosphogypsum, the weight of the modifier is 0.5-1% of the weight of the phosphogypsum; the weight of CaO is 0.5-1% of the weight of the phosphogypsum.

2. The filling material based on phosphogypsum according to claim 1, characterized in that: The phosphate tailings include coarse aggregate or fine aggregate.

3. The filling material based on phosphorus-doped gypsum according to claim 2, characterized in that: The filling material, by weight percentage, comprises: 12% of cement, 48% of phosphogypsum, 20% of fly ash, and 20% of fine aggregate.

4. A filling material based on phosphogypsum according to claim 1, characterized in that: The phosphate tailings include coarse aggregate and fine aggregate, and the mass ratio of the coarse aggregate to the fine aggregate is 1:2-3.

5. A filling material based on phosphorus-doped gypsum according to claim 4, characterized in that: The filling material, by weight percentage, comprises: 12% of cement, 48% of phosphogypsum, 20% of fly ash, 5% of coarse aggregate, and 15% of fine aggregate.

6. The filling material based on phosphorus-containing gypsum according to claim 1, characterized in that: The modifier, by weight percentage, comprises: 20%-30% of polyacrylic acid emulsion, 25%-45% of nano-silica, 25%-45% of nano-alumina, and 30% of sodium methyl silicate.

7. The preparation method of a filling material based on phosphorus-containing gypsum according to claim 1, characterized in that: Comprising the following steps: S1. Weigh cement, phosphogypsum, fly ash, and phosphate tailings in a ratio of 8-12%:40-87%:10-20%:20-30%. S2. Add the modifier and CaO to the phosphogypsum, and add water and stir evenly to obtain a slurry, then let it stand for standby. S3. Add the weighed cement, fly ash, coarse aggregate, and phosphate tailings to the slurry obtained in step S2, and add water and stir evenly to obtain the filling material; the water content of the filling material is 10-30%.

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