Phosphorite-based all-solid-waste synergistic filling slurry as well as optimization method and application thereof

Abstract

The invention belongs to the technical field of filling mining, and particularly relates to phosphorite-based all-solid-waste synergistic filling slurry as well as an optimization method and application of the phosphorite-based all-solid-waste synergistic filling slurry. The optimization method comprises the following steps: mixing phosphogypsum, phosphorus slag powder and an alkali activator to obtain a cementing material; mixing the cementing material, the phosphate tailings and water according to different lime-sand ratios and mass concentrations to obtain different filling slurries, and respectively measuring the filling body strength, the slump, the diffusivity, the filling body leachate phosphate content, the filling body leachate fluoride content and the pH value of the different filling slurries; and constructing a mathematical function model, and solving optimal numerical values of the cement-sand ratio and the mass concentration under an optimization target and constraint conditions. The optimization method can reduce the filling cost on the premise of meeting the requirements of mine filling strength, fluidity and environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of backfilling mining technology, specifically relating to a phosphate rock-based all-solid waste co-filling slurry, its optimization method, and its application. Background Technology

[0002] Under current technological conditions, backfilling mining is an effective measure to control ground pressure during deep mining. Its advantages include strong adaptability, high ore recovery rate, and relatively safe operation. However, its disadvantages include complex processes, high costs, and environmentally unfriendly slurry formulations. For example, in phosphate mining, the large-scale accumulation of solid waste such as phosphate tailings, phosphogypsum, and phosphate slag pollutes the environment. To achieve resource utilization of solid waste, attempts are made to prepare cementitious materials or fillers from these wastes. However, existing cementitious materials or fillers made primarily from phosphorus-containing substances such as phosphogypsum and phosphate tailings often require large amounts of high-value-added materials such as slag, cement, or fly ash, resulting in numerous component ratios and high production costs. Furthermore, for backfilling goafs or open-pit filling remediation, traditional cementitious materials such as cement have poor solidification effects, difficulty in roof support, and unsatisfactory performance. Furthermore, existing methods for preparing cementitious materials often require pretreatment processes such as calcination and grinding of phosphogypsum, resulting in complex and energy-intensive processes. The preparation and application processes also fail to consider the solidification effect on harmful substances or the control of environmental indicators such as pH, phosphorus, and phosphorus. Additionally, these cementitious materials or fillers have low utilization rates of industrial solid waste, making it difficult to achieve large-scale, volume-reduced applications. Summary of the Invention

[0003] Therefore, the purpose of this invention is to provide a phosphate rock-based solid waste co-filling slurry, its optimization method, and its application. The solid waste content in this filling slurry is 95% or more, eliminating the need for additional processes such as grinding and calcining of phosphogypsum. Furthermore, the optimization method comprehensively considers cost, mechanical properties, and environmental indicators, thereby reducing filling costs while meeting the operating conditions and environmental requirements.

[0004] To this end, the present invention provides the following technical solution.

[0005] This invention provides an optimized method for phosphate rock-based all-solid waste co-filling slurry, comprising the following steps: S1: Mix phosphogypsum, phosphorus slag powder, and alkali activator to obtain a cementitious material; S2: Mix the cementitious material, phosphate tailings, and water with different ash-sand ratios and mass concentrations to obtain different filling slurries. Measure the filling strength, slump, spread, phosphate content in the leachate of the filling body, fluoride content in the leachate of the filling body, and pH value of the different filling slurries, and calculate the unit cost of the filling slurry. S3: Based on the different ash-sand ratios, mass concentrations, and filling strength, slump, diffusivity, phosphate content of the filling leachate after 28 days, fluoride content of the filling leachate after 28 days, pH value of the filling leachate after 28 days, and unit filling slurry cost obtained in S2, the following quadratic polynomial stepwise regression analysis mathematical model is established. The mathematical model for the strength of filling materials is as follows: R n = f 1( C s , w ); The mathematical function model for slump is: T = f 2( C s , w ); The mathematical model for diffusion is: K = f 3( C s , w ); The mathematical function model for the phosphate content of the leachate from the filling material after 28 days is as follows: P 28d = f 4( C s , w ); The mathematical function model for the fluoride content in the leachate of the filling body after 28 days is as follows: F 28d = f 5( C s , w ); The mathematical function model for the pH value of the leachate from the filling body after 28 days is as follows: pH 28d = f 6( C s , w ); The mathematical function model for the unit filling slurry cost is as follows: C=f 7( C s , w ); in, R n for n The compressive strength of the infill material at 30 years of age, expressed in MPa; T The slump of the filling slurry, K The diffuseness of the filling slurry is expressed in cm. P 28dThe phosphate content of the leachate from the infill body at 28 days of age is expressed in mg / L. F 28d The fluoride content in the leachate of the infill body at 28 days of age is expressed in mg / L. pH 28d The pH value of the leachate from the infill body at 28 days of age; C The cost of the filling slurry is expressed in yuan / m³. 3 ; C s The cement-sand ratio of the filling slurry; w The mass concentration of the filling slurry is expressed in % (%). S4: Using the mathematical function model established in S3, the optimized values ​​of the ash-sand ratio and mass concentration are obtained under the optimization objectives and constraints. The optimization objective is: M in C = M in[ f 7( C s , w )]; The constraints include: R n ≥ R n d , ≤ T ≤ , ≤ K ≤ , ≤ , ≤ , ≤ ≤ ; in, M in C To achieve the lowest unit cost of filling slurry, R n d for n The lower limit of the design compressive strength of the filling material for the day. This is the lower limit of the slump design value. The upper limit of the slump design value, This is the lower limit of the design value for diffusivity. The upper limit of the design value for diffusivity, The phosphate content control index for leachate of 28-day-old infill bodies. The fluoride content in the leachate of 28-day-old infill bodies is a control index. This represents the lower limit of the pH control index for the leachate of infill bodies aged 28 days. The upper limit of the pH value control index for the leachate of 28-day-old filling bodies.

[0006] In the optimization method for phosphate rock-based all-solid waste co-filling slurry provided by this invention, the ash-sand ratio is the mass ratio of cementitious material to phosphate tailings. The mass concentration is the mass concentration of the solid components in the filling slurry.

[0007] In the optimized method of phosphate rock-based solid waste co-filling slurry provided by the present invention, typically and without limitation, the method of mixing the raw materials in S1 to obtain the cementitious material includes mixing with a mixer or mixing with a mill; preferably, a mill is used for mixing.

[0008] Optionally, in S1, the cementing material includes, by weight percentage: 20%~40% phosphogypsum, 50%~65% phosphorus slag powder, and 3%~20% alkali activator; or, the cementing material includes, by weight percentage: 20%~35% phosphogypsum, 50%~60% phosphorus slag powder, and 5%~20% alkali activator.

[0009] Optionally, in step S1, the cementitious material further includes 0-15% modifier by weight; alternatively, it also includes 0-10% modifier. Modifiers can be selectively added according to the raw materials and target performance to obtain cementitious materials that meet the expected use.

[0010] Optionally, after step S4, the method further includes a step of preparing the filling slurry based on the optimized values ​​of the obtained ash-sand ratio and mass concentration.

[0011] Optionally, the phosphogypsum contains ≥70% CaSO4·2H2O and ≤2% moisture.

[0012] Optionally, the mass coefficient of the phosphorus slag powder ≥1.2.

[0013] Optionally, before step S1, the process further includes a step of drying phosphogypsum at a temperature ≤60°C.

[0014] Optionally, before S1, the process may include grinding the phosphorus slag powder until the residue on a 45μm sieve is ≤3%.

[0015] Optional, 25cm≤ <28cm, 25cm< ≤28cm.

[0016] Optional, 45cm≤ <85cm, 45cm< ≤85cm.

[0017] Optional, ≤0.5mg / L.

[0018] Optional, ≤10mg / L.

[0019] Optional, 6≤ <9,6< ≤9.

[0020] Optionally, the alkali activator includes at least one of red mud, carbide slag, steel slag, and refining slag. Instead of using expensive raw materials such as cement clinker, quicklime, and hydrated lime, alkaline solid wastes such as red mud, carbide slag, steel slag, and refining slag are used as alkali activators. Furthermore, no pretreatment steps such as grinding are required, allowing for direct use, which further reduces production costs and improves the utilization rate of solid waste.

[0021] Optionally, the modifier includes at least one of slag powder, fly ash, and an early-strength agent. With a modifier content of only 0-10%, the amount of high-value solid waste such as slag powder and fly ash used in this invention is relatively small, while difficult-to-treat solid wastes such as phosphorus slag and phosphogypsum are used as active raw materials, which can optimize production costs and improve the utilization rate of solid waste. The slag powder is obtained by grinding blast furnace water-quenched slag.

[0022] The present invention also provides an optimized method for obtaining the above-mentioned phosphate rock-based solid waste co-filling slurry.

[0023] Optionally, the backfilling mining process includes any one of the following: open-stope backfilling mining process, upward layered backfilling mining process, and downward layered backfilling mining process.

[0024] Optionally, at least one of the following conditions must be met: A. When using the open-cut backfilling mining process, bottom backfilling and roof backfilling are performed. R 28 d ≥2.0MPa, intermediate filling R 28 d ≥0.5MPa; B. When using the upward layered backfilling mining process, the surface backfill... R 28 d ≥2.0MPa, artificial base column (or first and second layers) R 28 d ≥4.0MPa, other locations R 28 d ≥0.5MPa; C. When using the downward layered backfilling mining process, construct a false roof backfill. R 7d ≥1.5MPa R 28 d ≥4.0MPa, other locations R 28 d ≥1.0MPa; D. In the treatment of open-pit filling, the bottom and surface of the pit... R 28 d ≥1.5MPa, other locations R 28 d ≥0.5MPa.

[0025] The beneficial effects of this invention are: The present invention provides an optimization method for phosphate rock-based solid waste co-filling slurry, comprising the following steps: mixing phosphogypsum, phosphate slag powder, and alkali activator to obtain a cementitious material; mixing the cementitious material, phosphate tailings, and water with different ash-sand ratios and mass concentrations to obtain different filling slurries; measuring the filling strength, slump, spread, phosphate content in the filling leachate, fluoride content in the filling leachate, and pH value of different filling slurries; constructing a quadratic polynomial stepwise regression analysis mathematical model to obtain optimized values ​​for the ash-sand ratio and mass concentration under optimization objectives and constraints. In this optimized method for phosphate rock-based solid waste co-filling slurry, the activity of phosphate slag, the hydraulic properties of phosphogypsum, and the activating effect of sulfate are utilized. A suitable activator is added to prepare a phosphate rock solid waste backfilling cementitious material, which is then synergistically combined with phosphate tailings to produce a backfilling slurry. This slurry can be used for mine solidification backfilling, not only realizing the resource utilization and high-value-added use of phosphate rock solid waste, but also solving the environmental pollution problem caused by the large-scale stockpiling of solid waste such as phosphate tailings, phosphogypsum, and phosphate slag, while reducing backfilling costs. Slump and spread are both flowability indicators. The phosphate content, fluoride content, and pH value of the backfill leachate are optimized from an environmental protection perspective. This invention, by constructing a mathematical function model and employing a multi-objective algorithm to optimize the slurry ratio, reduces backfilling costs while meeting the requirements for mine backfilling strength, flowability, and environmental protection. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 The particle size characteristic curves of phosphate tailings, phosphogypsum, and phosphate slag in Experiment Example 1 are shown. Figure 2 The particle size characteristic curves of phosphorus tailings, phosphogypsum, and phosphorus slag in Experiment Example 2 are shown. Detailed Implementation

[0028] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0029] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0030] Experimental Example 1 The chemical composition (wt%) of phosphate tailings, phosphogypsum, and phosphate slag powder produced by a phosphate chemical company in Guizhou is shown in Table 1. After grinding the phosphate slag powder, its particle size characteristic curve was tested as follows: Figure 1 As shown in Table 1 (the horizontal axis represents the particle size on a logarithmic scale). Figure 1 It can be seen that the content of phosphogypsum (CaSO4·2H2O) in the above raw materials is 82%, and the quality coefficient of phosphorus slag is... Z =1.4, and the residue on a 45μm sieve after grinding of phosphorus slag is 2.2%.

[0031] Table 1

[0032] The phosphogypsum was dried at 60℃ to a moisture content of 1.5%. Using red mud as an alkali activator and slag powder (meeting S95 grade requirements) as a modifier, nine portions of phosphogypsum, slag powder, alkali activator, and modifier in different proportions were added to a mill and ground for 5 minutes to ensure uniform mixing, thus obtaining the cementitious material. The sample preparation, curing, and determination of 3-day, 7-day, and 28-day compressive strength were performed according to GB / T 51450-2022 "Technical Standard for Backfilling Engineering in Metal and Non-metal Mines". Specific formulations and compressive strength data are shown in Table 2.

[0033] Table 2

[0034] According to the data in Table 2, it can be seen that the raw material ratio corresponding to No. 1-2 has the best compressive strength. Subsequent experiments were carried out using No. 1-2 as the cementing material.

[0035] Experiment Example 2 The chemical composition (wt%) of phosphate tailings, phosphogypsum, and phosphate slag produced by a phosphate chemical company in Hubei Province is shown in Table 3. After grinding the phosphate slag, its particle size characteristic curve was tested as follows: Figure 2 As shown in Table 3 (the horizontal axis represents the particle size on a logarithmic scale). Figure 2 It can be seen that the content of phosphogypsum (CaSO4·2H2O) in the above raw materials is 85%, and the quality coefficient of phosphorus slag is... Z =1.26, and the residue on a 45μm sieve after grinding of phosphorus slag is 1.6%.

[0036] Table 3

[0037] The phosphogypsum was dried at 55℃ to a moisture content of 1.2%. Using carbide slag as an alkali activator and fly ash (meeting Class II standards) as a modifier, nine portions of phosphogypsum, phosphogypsum powder, alkali activator, and modifier in different proportions were added to a mill and ground for 5 minutes to ensure uniform mixing, thus obtaining the cementitious material. The sample preparation, curing, and determination of 3-day, 7-day, and 28-day compressive strength were performed according to GB / T 51450-2022 "Technical Standard for Backfilling Engineering in Metal and Non-metal Mines". Specific formulations and compressive strength data are shown in Table 4.

[0038] Table 4

[0039] According to the data in Table 4, it can be seen that the raw material ratios corresponding to numbers 2-5 have the best compressive strength. Subsequent experiments were carried out using numbers 2-5 as cementing materials.

[0040] Example 1 This embodiment provides an optimization method for phosphate rock-based all-solid waste co-filling slurry, which specifically includes the following steps: (1) Prepare cementitious materials using the same proportions and methods as those corresponding to cementitious materials numbered 1-2 in Experiment 1.

[0041] (2) The cementing material in (1), the phosphorus tailings in Experiment 1, and water were mixed with different ash-sand ratios (mass ratio of cementing material to phosphorus tailings) and mass concentrations to obtain different filling slurries. The strength, slump, and spread of the filling body of the different filling slurries were determined with reference to GB / T 51450-2022 "Technical Standard for Filling Engineering of Metal and Non-metal Mine". The phosphate content, fluoride content, and pH value of the filling body leachate were determined with reference to HJ 557-2010 "Horizontal Oscillation Method for Leaching Toxicity of Solid Waste". The unit cost was calculated. The data obtained are shown in Table 5.

[0042] Table 5

[0043] (3) Based on the data in Table 5, the following mathematical function model is established using the method of quadratic polynomial stepwise regression: Compressive strength: R 28d = f 1 (C s ，w)= 22.13 + 25.43 C s - 0.93 w +1.35 C s w- 269.41 C s 2 +0.0072 w 2 ; Slump: T = f 2( C s , w = -189.1 + 102.31 C s +6.28 w -0.52 C s w -151.49 C s 2 -0.047 w 2 ; Diffusion: K = f 3( C s , w = 3721.8 + 1635.4 C s -105.83 w -17.49 C s w -945.32 C s 2 +0.76 w 2 ; Phosphate content in leachate of 28-day-old filling bodies: P 28d = f 4( Cs , w = -3.11 - 7.31 C s +0.14 w +0.076 C s w +4.01 C s 2 -0.0013 w 2 ; Fluoride content in leachate of 28-day-old fillings: F 28d = f 5( C s , w =76.53-32.81 C s -1.98 w +0.33 C s w +22.79 C s 2 +0.013 w 2 ; pH value of leachate from 28-day-old infill bodies: pH 28d = f 6( C s , w =24.62 - 85.41 C s +0.088 w +1.05 C s w +19.49 C s 2 -0.0044 w 2 ; Unit filling slurry cost: C=f 7( C s , w =148.38 - 68.33 C s -4.26 w +3.57 C sw -100.73 C s 2 +0.031 w 2 .

[0044] (4) The mine adopts the open-pit backfilling method. Considering slump, diffusion and environmental protection requirements, the constraints are as follows: R 28d ≥2MPa, 25cm≤ T ≤28cm, 45cm≤ K ≤85cm P 28d ≤0.5mg / L, F 28d ≤10mg / L, 6≤ pH 28d ≤9; The optimization objective is: M in C = M in[146.88-68.33 C s -4.26 w +3.57 C s w -100.73 C s 2 +0.031 w 2 ].

[0045] The lowest cost formulation of the phosphate rock-based solid waste co-filling slurry was determined to be: a lime-to-sand ratio of 1:8.2 and a mass concentration of 68%. Under this formulation, the 28-day strength is 2.47 MPa, the slump and spread are 26.5 cm and 79.9 cm, respectively, and the phosphate (P), fluoride (F), and pH values ​​of the leachate from the filling body at 28 days are 0.20 mg / L, 1.08 mg / L, and 8.84, respectively, all meeting the requirements for mine filling. The corresponding filling slurry cost is 21.82 yuan / m³. 3 .

[0046] Example 2 This embodiment provides an optimization method for phosphate rock-based all-solid waste co-filling slurry, which specifically includes the following steps: (1) Prepare cementitious materials using the same proportions and methods as those corresponding to cementitious materials numbered 2-5 in Experiment 2.

[0047] (2) The cementitious material in (1), the phosphorus tailings in Experiment 2, and water were mixed with different ash-sand ratios and mass concentrations to obtain different filling slurries. The strength, slump, diffusion, phosphate content in the leachate of the filling material, fluoride content in the leachate of the filling material, and pH value of the filling slurry were measured respectively, and the unit cost was calculated. The data obtained are shown in Table 6.

[0048] Table 6

[0049] (3) Based on the data in Table 6, the following mathematical function model is established using the method of quadratic polynomial stepwise regression: Compressive strength: R 7d = f 1( C s , w =3.92 - 2.26 C s -0.26 w +0.58 C s w -82.29 C s 2 +0.0025 w 2 ; R 28d = f 2 (C s ，w)= 180.96-10.41 C s - 5.56 w +1.70 C s w- 245.61 C s 2 +0.0413 w 2 ; Slump: T = f 2( C s , w =300.98 - 47.15 C s -7.7 w +1.15 C sw -56.75 C s 2 +0.053 w 2 ; Diffusion: K = f 3( C s , w = 4611.8 + 1452.69 C s -134.4 w -15.87 C s w -874.26 C s 2 +0.9875 w 2 ; Phosphate content in leachate of 28-day-old filling bodies: P 28d = f 4( C s , w = 5.4175 - 6.6597 C s -0.1164 w +0.0635 C s w +5.0334 C s 2 +0.000625 w 2 ; Fluoride content in leachate of 28-day-old fillings: F 28d = f 5( C s , w =122.84 - 19.63 C s -3.445 w +0.204 C s w +12.12 C s 2 +0.0244 w 2 ; pH value of leachate from 28-day-old infill bodies: pH 28d = f 6( C s , w =38.96 - 68.221 C s -0.365 w +0.737 C s w +38.313 C s 2 -0.0009375 w 2 ; Unit filling slurry cost: C=f 7( C s , w = -11.4615 - 25.3353 C s +0.1573 w +3.6948 C s w -171.6712 C s 2 .

[0050] (4) The mine adopts the downward layered filling method. Considering slump, diffusion and environmental protection requirements, the constraints are as follows: R 7d ≥1.5MPa R 28d ≥4MPa, 25cm≤ T ≤28cm, 45cm≤ K ≤85cm P 28d ≤0.5mg / L, F 28d ≤10mg / L, 6≤ pH 28d ≤9; The optimization objective is: M in C = M in[-11.46-25.34 C s +0.16 w +3.69 C sw -171.67 C s 2 ].

[0051] The lowest cost formulation of the phosphate rock-based all-solid-waste co-filling slurry was determined to be: a lime-sand ratio of 1:6.85 and a mass concentration of 69.6%. Under this formulation, the 7-day and 28-day strengths were 1.74 MPa and 4.57 MPa, respectively; the slump and spread were 25.4 cm and 73.4 cm, respectively; and the P, F, and pH values ​​of the leachate from the 28-day-old filling body were 0.12 mg / L, 0.73 mg / L, and 7.36, respectively, all meeting the mine filling requirements. The corresponding filling slurry cost was 29.67 yuan / m³. 3 .

[0052] Comparative Example 1 This comparative example provides an optimization method for phosphate rock-based solid waste co-filling slurry. Compared with Example 1, the only difference is that in step (3), when establishing the mathematical function model, the index model of the 28-day-old filling body leachate is not considered, that is, the phosphate content, fluoride content, and pH value of the 28-day-old filling body leachate are not considered.

[0053] The lowest cost formulation of the phosphate rock-based all-solid-waste co-filling slurry obtained from the solution is: a ash-to-sand ratio of 1:8.5 and a mass concentration of 68.3%. Under this formulation, the 28-day strength was measured to be 2.46 MPa, the slump to be 25.8 cm, the spread to be 76.3 cm, and the P, F, and pH values ​​of the leachate from the filling body at 28 days of age were 0.19 mg / L, 1.2 mg / L, and 9.10, respectively. In the lowest cost formulation of the filling slurry obtained in this comparative example, the pH of the leachate from the filling body at 28 days of age exceeds 9, which fails to meet environmental protection requirements.

[0054] Comparative Example 2 This comparative example provides an optimization method for phosphate rock-based solid waste co-filling slurry. Compared with Example 2, the only difference is that in step (3), when establishing the mathematical function model, the fluidity model is not considered, that is, the slump and diffusion are not considered.

[0055] The lowest cost formulation of the phosphate rock-based all-solid-waste co-filling slurry obtained from the solution is: a ash-to-sand ratio of 1:8.6 and a mass concentration of 72.3%. Under this formulation, the measured 7-day strength is 1.67 MPa, the 28-day strength is 4.15 MPa, the slump is 24.9 cm, the spread is 70.5 cm, and the P, F, and pH values ​​of the leachate from the 28-day-old filling body are 0.15 mg / L, 0.79 mg / L, and 7.41, respectively. In the lowest cost formulation of the filling slurry obtained in this comparative example, the slump is less than 25 cm, which cannot meet the requirements for mine use.

[0056] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for optimizing a phosphate rock-based total solid waste synergic filling paste, characterized in that, Comprising the following steps: S1: mixing phosphogypsum, phosphorus slag powder, alkali activator to obtain cementitious material; S2: mixing the cementitious material, phosphorus tailings, water in different sand ratio and mass concentration to obtain different filling slurry, respectively measuring the filling body strength, slump, diffusion degree, filling body leaching solution phosphate content, filling body leaching solution fluoride content, pH value of different filling slurry, and calculating the unit filling slurry cost; S3: establishing the following quadratic polynomial stepwise regression analysis mathematical model through the different sand ratio, mass concentration and filling body strength, slump, diffusion degree, filling body leaching solution 28d phosphate content, filling body leaching solution 28d fluoride content, filling body leaching solution 28d pH value, unit filling slurry cost obtained in S2; The mathematical function model of the filling body strength is: R n = f 1( C s , w ); The mathematical function model of slump degree is: T = f 2( C s , w ); The mathematical function model of the diffusion degree is: K = 1 - exp(-3( f C s , w ));​ The mathematical function model of the phosphate content of the leaching solution 28d of the filling body is: P 28d = f 4( C s , w ); The mathematical function model of the fluoride content of the leaching solution 28d of the filling body is: F 28d = f 5( C s , w ); The mathematical function model of the pH value of the filler leaching liquid 28d is: pH 28d = f 6( C s , w ); The mathematical function model of unit filling slurry cost is: C=f 7( C s , w ); wherein, R n is n compressive strength of the filling body at the age of 28 d, unit: MPa; T is the slump of the filling slurry, K is the spread of the filling slurry, unit: cm; P 28d is the phosphate content of the leaching liquid of the filling body at the age of 28 d, unit: mg / L; F 28d is the fluoride content of the leaching liquid of the filling body at the age of 28 d, unit: mg / L; pH 28d is the pH value of the leaching liquid of the filling body at the age of 28 d; C is the unit cost of the filling slurry, unit: yuan / m 3 ; C s is the sand-cement ratio of the filling slurry; w is the mass concentration of the filling slurry, unit: %; S4: obtaining the optimization value of sand ratio and mass concentration under the optimization target and constraint condition through the mathematical function model established in S3; The optimization objective is: M in C = M in[ f 7( C s , w )] The constraints include: R n ≥ R n d , ≤ T ≤ , ≤ K ≤ , ≤ , ≤ , ≤ ≤ ; wherein, M in C is the lowest unit backfill slurry cost, R n d is n is the lower limit of the compressive strength design value of the backfill body for the day, is the lower limit of the slump design value, is the upper limit of the slump design value, is the lower limit of the diffusivity design value, is the upper limit of the diffusivity design value, is the 28d age backfill body leaching liquid phosphate content control index, is the 28d age backfill body leaching liquid fluoride content control index, is the lower limit of the 28d age backfill body leaching liquid pH value control index, is the upper limit of the 28d age backfill body leaching liquid pH value control index.

2. The method for optimization of phosphate rock-based total solid waste synergic filling slurry according to claim 1, characterized in that, In the S1, the cementitious material comprises, by weight percentage: 20%-40% of phosphogypsum, 50%-65% of phosphorus slag powder, and 3%-20% of alkali activator; optionally, the cementitious material comprises, by weight percentage: 20%-35% of phosphogypsum, 50%-60% of phosphorus slag powder, and 5%-20% of alkali activator; And / or, in the S1, the cementitious material further comprises, by weight percentage: 0-15% of modifier; optionally, further comprising 0-10% of modifier; And / or, after the S4, further comprising the step of preparing filling slurry according to the obtained optimization value of sand ratio and mass concentration.

3. The method for optimization of phosphate rock-based total solid waste synergic filling slurry according to claim 1 or 2, characterized in that, In the phosphogypsum, the content of CaSO4·2H2O is ≥70%, and the water content is ≤2%; and / or the mass coefficient of the phosphorous slag powder ≥ 1.

2.

4. The method for optimizing phosphate rock-based total solid waste synergic filling slurry according to any one of claims 1 to 3, characterized in that, Before the S1, further comprising the step of drying the phosphogypsum, and the drying temperature is ≤60℃; And / or, before the S1, further comprising the step of grinding the phosphorus slag powder to ≤3% of 45μm residue.

5. The method for optimization of phosphate rock-based total solid waste synergic filling slurry according to any one of claims 1 to 4, characterized in that, 25 cm < L < 30 cm < 28 cm, 25 cm < L < 30 cm ≤ 28 cm; and / or, 45 cm < H < 85 cm < 85 cm, 45 cm < H ≤ 85 cm; and / or, ≤ 0.5 mg / L; and / or, ≤ 10 mg / L; and / or, 6 < x < 9 <9, 6 < x ≤ 9.

6. The method for optimization of phosphate rock-based total solid waste synergic filling slurry according to any one of claims 2 to 5, characterized in that, The alkali activator comprises at least one of red mud, carbide slag, steel slag, and refining slag; And / or, the modifier comprises at least one of slag powder, fly ash, and early strength agent.

7. A phosphorus mine-based full-solid waste collaborative filling slurry obtained by the optimization method of the phosphorus mine-based full-solid waste collaborative filling slurry according to any one of claims 1 to 6.

8. The application of the phosphorus mine-based full-solid waste collaborative filling slurry according to claim 7 in filling mining process or pit filling treatment.

9. Use according to claim 8, characterized in that, The filling mining process comprises any one of open stope backfill mining process, upward slicing filling mining process, and downward slicing filling mining process.

10. Use according to claim 9, characterized in that, At least one of the following conditions is met: A, when using the open stope and subsequent filling mining process, the bottom and top filling R 28 d ≥ 2.0 MPa, intermediate filling R 28 d ≥ 0.5 MPa; B. When using the upward slicing and filling mining process, the surface filling R 28 d ≥ 2.0 MPa, artificial bottom pillar R 28 d ≥ 4.0 MPa, other locations R 28 d ≥ 0.5 MPa; C. When using the downward slicing and filling mining process, make false roof filling body R 7 d ≥ 1.5 MPa, R 28 d ≥ 4.0 MPa, other locations R 28 d ≥ 1.0 MPa; D. In the open pit filling treatment, the pit bottom and surface layer R 28 d ≥ 1.5 MPa, other positions R 28 d ≥ 0.5 MPa.

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