CN113387671B - Optimization method for water resistance and stability of all solid waste filling materials in Dashui mines - Google Patents

Abstract

The invention provides a method for optimizing the proportion of a full-solid waste filling material with water resistance stability in a large water mine, which relates to the technical field of solid waste utilization, can realize the optimized combination and synergistic effect of solid waste resources, prepare the filling material meeting the water resistance requirement, and provide support for safe and reliable low-quality solid waste and large-scale resource utilization; the method comprises the following steps: s1, preparing a plurality of mixed powder with different proportions, including phosphogypsum and blast furnace slag; s2, carrying out a filler strength test and a water resistance test on all the mixed powder to obtain test results of the mixed powder with different proportions; s3, establishing a mathematical model of the strength of the filling body and a mathematical model of the water-resistant stability according to the test result; s4, establishing a full-solid waste filling material proportion optimization model by taking the filling material cost as an optimization target and the two mathematical models as constraint conditions; and S5, solving the model to obtain the optimized proportion of the full-solid waste filling material. The technical scheme provided by the invention is suitable for the mine filling process.

Description

Optimization method for water resistance and stability of all solid waste filling materials in Dashui mines

technical field

The invention relates to the technical field of solid waste utilization, in particular to a method for optimizing the proportion of filling materials for all solid wastes with water resistance and stability in Dashui mines.

Background technique

With the rapid development of my country's economy and the continuous development and utilization of mineral resources, high-grade mineral resources with good mining technology conditions are increasingly depleted, and more resources are faced with deep burial, high stress, rich water and poor formation conditions. The first choice for safety, environmental protection and green mining in backfill mining. The tailings cemented backfill with cement as the gelling agent has low strength and poor fluidity, resulting in a large amount of cementitious material and high backfill mining costs.

With the introduction of my country's new environmental protection law and strict management, high-activity blast furnace slag has become a valuable resource, not only the utilization cost is increasing year by year, but also in some areas in my country is still in short supply. However, low-quality solid wastes such as phosphogypsum, carbide slag, steel slag, fly ash, and copper tailings have low resource utilization due to low activity. Therefore, the utilization of low-quality solid waste in backfill mining can not only reduce the cost of backfill mining, but also explore a way for the harmless, reduced and high-value utilization of low-quality solid waste.

Studies have shown that low-quality solid waste not only has poor activity and slow hydration reaction, resulting in low strength of the backfill, but also poor water resistance stability of the cemented backfill. Deterioration and reduction of strength, thereby potentially causing serious safety hazards to backfill mining. Therefore, when low-quality solid waste is used in backfill mining in large water mines, its water resistance stability is a problem worthy of attention.

Phosphogypsum is a solid waste of the phosphate fertilizer industry. With the rapid development of the high-concentration compound fertilizer industry in my country in recent years, a large amount of phosphogypsum is discharged from phosphate fertilizer chemical companies every year. Due to the presence of harmful mineral components in phosphogypsum, the activity is low and the water resistance is poor, so the current utilization rate of phosphogypsum is less than 5%, and most of the phosphogypsum is piled up. It not only occupies a large amount of land, but also seriously pollutes the environment, thereby inhibiting the development of the phosphate fertilizer industry. Obviously, it is urgent to expand the resource utilization of low-quality solid waste such as phosphogypsum and fly ash.

Phosphogypsum contains harmful P ₂ O ₅ and other chemical components, resulting in low cement strength and accompanying water swelling and strength deterioration. This is the main factor that affects the utilization of phosphogypsum as a bulk resource. For this reason, people are constantly exploring Key technologies and application fields of phosphogypsum resource utilization. Chinese invention patent CN 103133033 A discloses "a method for cementing and filling pulping of phosphogypsum in mines", and CN 108191365 A discloses "a method for cementing and filling metal mines with phosphogypsum materials". Quality filling material pulping process, but does not involve the water resistance stability of the filling body. Chinese invention patent CN 109133830 A discloses "a preparation method of low-quality self-leveling material", which expands the resource utilization approach of phosphogypsum in the technical field of building materials. Chinese invention patent CN 107382239 A discloses "full solid waste filling material and preparation method for stabilizing dioxin-containing incineration fly ash", using phosphogypsum to prepare all-solid waste filling material, which is used to stabilize and solidify dioxin-containing incineration fly ash Solid waste such as ash, and does not consider the strength of the cured body and the stability of water resistance.

In summary, the water resistance stability of the cemented backfill in Dashui Mine will not only affect the stability and safety of the backfill stope, but also play a crucial role in controlling the deformation of surrounding rock, roof caving, and induced flooding and other catastrophic accidents. At present, the method of improving the water resistance stability of the backfill is mainly to add fibers or additives and water-resistant materials, which not only increases the cost of backfill mining, but also complicates the recovery process.

Therefore, it is necessary to study a method for optimizing the proportion of all-solid waste filling materials with water resistance and stability in Dashui mines to deal with the deficiencies of the prior art, so as to solve or alleviate one or more of the above problems.

SUMMARY OF THE INVENTION

In view of this, the present invention provides a method for optimizing the proportion of all-solid waste filling materials with water resistance and stability in Dashui mines, which can realize the optimal combination and synergy of solid waste resources, and prepare all-solid waste filling materials that meet water resistance requirements. , to provide support for the safe, reliable and bulk resource utilization of low-quality solid waste in flooded mines.

The invention provides a method for optimizing the proportion of all-solid waste filling materials with water resistance and stability in Dashui mines, characterized in that the steps of the method include:

S1. Drying and grinding the solid waste material to obtain mixed powders with different ratios; each of the mixed powders includes phosphogypsum and blast furnace slag;

S2. Carry out the strength test and water resistance test of the filling body for all the mixed powders obtained in S1, and obtain the results of the filling body strength test and the water resistance performance test results of the mixed powders with different ratios;

S3. According to the backfill strength test results and water resistance test results obtained in S2, establish a backfill strength mathematical model and a water resistance stability mathematical model;

S4. Taking the cost of the filling material as the optimization objective, and taking the mathematical model of the strength of the backing body and the mathematical model of the water resistance stability obtained in S3 as the constraints, an optimization model for the proportion of all-solid waste filling materials is established;

S5. Solving the optimal proportioning model of the all-solid-waste filling material obtained in S4, and obtaining the optimal proportioning of the all-solid-waste filling material.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the parameter requirements of the phosphogypsum include: P ₂ O ₅ ≤5%, moisture content≤3%, MgO≤3% and specific surface area ≥200m ² /kg.

The above aspects and any possible implementation manners further provide an implementation manner, the parameter requirements of the blast furnace slag include: the fineness of the blast furnace slag fine powder≤5% or the specific surface area≥420m ² /kg, the quality coefficient≥1.6 , activity index ≥ 0.3 and moisture content < 3%.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, wherein the mixed powder further includes one or more of carbide slag, fly ash and copper slag.

According to the above aspect and any possible implementation manner, an implementation manner is further provided. The parameter requirements of the carbide slag, the fly ash and the copper separation tailings include: moisture content <3% and specific surface area ≥300m ² /kg.

The above aspects and any possible implementations further provide an implementation, when the mixed powder includes phosphogypsum, blast furnace slag and carbide slag, the mass ratio of each component is: 40%-65% of phosphogypsum , blast furnace slag 15%-40%, calcium carbide slag 10%-20%;

When the mixed powder includes phosphogypsum, blast furnace slag, carbide slag and copper dressing tailings, the mass proportion of each component is: 40%-50% of phosphogypsum, 25%-35% of blast furnace slag, and 10%-15% of calcium carbide slag. %, copper tailings 5%-20%;

When the mixed powder includes phosphogypsum, blast furnace slag, carbide slag and fly ash, the mass proportion of each component is: 40%-50% of phosphogypsum, 25%-35% of blast furnace slag, and 10%-15% of calcium carbide slag , fly ash 5%-20%.

The above-mentioned aspects and any possible implementations further provide an implementation. The water-resistance test and the method for obtaining the results of the water-resistance test include: preparing two groups of filling body test blocks, placing them in water and Cured in a curing box; test the uniaxial compressive strength of the two groups of filling body test blocks, and use the ratio of the uniaxial compressive strength of the filling body test blocks under the two curing conditions as the water resistance performance test result of the mixed powder.

The above-mentioned aspect and any possible implementation manner further provide an implementation manner, in step S3:

The second-order polynomial was used to perform regression analysis on the strength test results of the backfill, and the mathematical model of the 7d and 28d strength of the cemented backfill was established;

Regression analysis was carried out on the test results of water resistance performance by quadratic polynomial, and the mathematical model of water resistance stability of 28d backfill was established.

According to the above aspect and any possible implementation, an implementation is further provided, wherein the mathematical model of the strength of the cemented filling bodies 7d and 28d is:

R _7d = f ₁ (x ₁ , x ₂ ,..., x _n ), R _28d = f ₂ (x ₁ , x ₂ ,..., x _n );

Among them, R _7d and R _28d represent the strength of the filling body 7d and 28d; x ₁ , x ₂ ,..., x _n represent the proportion of all solid waste filling materials; f ₁ and f ₂ represent the strength of the filling body 7d and 28d mixed with solid waste The relationship function of the addition;

The mathematical model of water resistance stability is:

K _28d = f ₃ (x ₁ , x ₂ , . . . , x _n );

Among them, K _28d represents the water resistance stability coefficient of the 28d filling body, x ₁ , x ₂ ,…, x _n represents the proportion of all solid waste filling materials, f ₃ represents the water resistance stability coefficient of the 28d filling body and the addition of solid waste Quantitative relationship function.

The above aspects and any possible implementations further provide an implementation. The all-solid waste filling material ratio optimization model described in step S4 includes:

Optimization objective: _MinCT = Minf _c (x ₁ , x ₂ ,..., x _n );

Constraints: R _7d = f ₁ (x ₁ , x ₂ ,..., x _n )≥[R _7d ]

R _28d =f ₂ (x ₁ ,x ₂ ,...,x _n )≥[R _28d ]

K _28d =f ₃ (x ₁ , x ₂ ,..., x _n )≥[K _28d ];

Among them, C _T represents the cost of all solid waste filling materials, and f _c (x ₁ , x ₂ ,..., x _n ) is the cost function of filling materials;

[R _7d ] and [R _28d ] represent the design values of the strength of the filling body 7d and 28d, and [K _28d ] represent the design value of the water resistance stability coefficient of the 28d filling body.

Compared with the prior art, one of the above technical solutions has the following advantages or beneficial effects: applying low-quality solid waste to backfill mining in large water mines can avoid potential catastrophic losses due to the deterioration of saturated water immersion strength in large water mines. Stabilizing risks and ensuring the safe use of low-quality solid waste in Dashui mines can not only improve the economic and environmental benefits of backfill mining, and promote the application of backfill mining technology, but also contribute to the reduction, harmlessness and resources of low-quality solid waste. Chemical utilization to find a way.

Of course, any product implementing the present invention does not necessarily need to achieve all the above-mentioned technical effects at the same time.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

Fig. 1 is a flow chart of a method for optimizing the proportioning of water-resistant and stable all-solid waste filling materials in Dashui mines provided by an embodiment of the present invention;

Fig. 2 is the phosphogypsum particle size distribution curve of Gansu Wengfu Company provided by an embodiment of the present invention;

Fig. 3 is the slag micropowder micropowder particle size gradation curve of Handan Iron and Steel Company provided by an embodiment of the present invention;

4 is a microscopic surface topography structure diagram of phosphogypsum provided by an embodiment of the present invention;

Fig. 5 is the phosphogypsum XRD pattern provided by an embodiment of the present invention;

Fig. 6 is a copper selection tailings sample provided by an embodiment of the present invention;

7 is a particle size distribution curve of copper separation tailings provided by an embodiment of the present invention;

Fig. 8 is a thermal power plant fly ash XRD diffractogram provided by an embodiment of the present invention;

FIG. 9 is a particle size distribution curve of fly ash in a thermal power plant provided by an embodiment of the present invention.

Detailed ways

In order to better understand the technical solutions of the present invention, the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

It should be understood that the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. As used in the embodiments of the present invention and the appended claims, the singular forms "a," "the," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

Aiming at the deficiencies of the existing technology, making full use of low-quality solid waste with various properties and different characteristics, cooperating with high-activity blast furnace slag, and developing water-resistant all-solid waste filling materials are the best way to improve the utilization of solid waste resources and reduce the cost of filling and mining. important way. The invention provides a water-resistant and stable low-quality all-solid waste filling material ratio optimization method for flood-filled mines. This method uses phosphogypsum as the main solid waste, and uses different characteristics of blast furnace slag micropowder, calcium carbide slag, fly ash, copper beneficiation tailings, etc. to conduct composite excitation and synergy mechanism, and establish an optimal model for the proportion of all solid waste filling materials. , to achieve the optimal combination and synergy of solid waste resources, thereby preparing all solid waste filling materials that meet the water resistance requirements, providing an optimal design for the safe, reliable and bulk resource utilization of low-quality solid waste in large water-filled mines method. As shown in Figure 1, the method steps include:

(1) Chemical analysis and table comparison test of low-quality solid waste and slag powder. Firstly, the solid waste used is dried and crushed into powder with a specific surface area ≥ 200m ² /kg (mainly refers to phosphogypsum), and the specific surface area of the blast furnace slag is ≥ 420m ² /kg or fineness ≤ 5%; according to It is necessary to select one or more low-quality solid wastes such as carbide slag, fly ash, copper tailings, etc., to prepare for the preparation of filling materials with blast furnace slag fine powder. The specific surface area of solid waste drying and grinding is greater than 400m ² /kg.

活性指数

高炉矿渣微粉细度≤5％或比表面积≥420m²/kg、含水率<3％；In the chemical composition of phosphogypsum, P ₂ O ₅ ≤ 5%, moisture content ≤ 3%, MgO ≤ 3%, specific surface area ≥ 200m ² /kg; the quality coefficient of blast furnace slag is

activity index

The fineness of blast furnace slag powder is less than or equal to 5% or the specific surface area is more than or equal to 420m ² /kg, and the moisture content is less than 3%;

Carbide slag, fly ash and copper tailings have a moisture content of <3% and a specific surface area of ≥300m ² /kg.

(2) Carry out tests on the strength and water resistance of the backfill with different proportions of solid waste filling materials. According to the different solid waste resources described in step (1), select the whole solid waste filling material system and dosage range. On this basis, the orthogonal test design of all-solid waste filling materials was carried out for the selected system, and the strength test and water resistance stability test of cemented backfill were carried out according to the strength test method of cement mortar B/T17671-1999, and the total solid waste was obtained. The test results of strength and water resistance stability of cemented backfill with different proportions of filling materials;

The content of the water resistance stability test can include: the design of the strength test of the filling body with different proportions of solid waste filling materials, preparing two groups of filling body test blocks, and placing them in water and a curing box for 28 days after demoulding, and then testing the two groups of test blocks. The uniaxial compressive strength of the block; the ratio of the strength of the test block under the two curing conditions is defined as the water resistance performance index of the filling. According to the test, the test results of the water resistance stability coefficient of the all-solid waste filling material filling body are obtained.

All-solid waste filling material systems include: phosphogypsum-slag fine powder-carbide carbide slag system, phosphogypsum-slag fine powder-carbide slag-copper tailings system, and phosphogypsum-slag fine powder-carbide carbide slag-fly ash system.

The ratio range of the phosphogypsum-slag micropowder-carbide slag system is: 40%-65% of phosphogypsum, 15%-40% of slag micropowder, and 10%-20% of calcium carbide slag. The ratio range of phosphogypsum-slag powder-carbide slag-copper tailings system is: phosphogypsum 40%-50%, slag powder 25%-35%, calcium carbide slag 10%-15%, copper tailings 5% -20%. The ratio range of phosphogypsum-slag powder-carbide slag-fly ash system is: phosphogypsum 40%-50%, slag powder 25%-35%, carbide slag 10%-15%, fly ash 5%-20% %.

(3) Establish a mathematical model for the strength and water resistance stability of the backfill. According to the test results of the backfill strength and water resistance stability of the all-solid waste filling material in step (2), the test data were regressed by using quadratic polynomial, and the backfill strength and water resistance under different curing age conditions (such as 7d and 28d) were established. The mathematical model of water stability is:

R _7d = f ₁ (x ₁ , x ₂ ,..., x _n ), R _28d = f ₂ (x ₁ , x ₂ ,..., x _n ), K _28d = f ₃ (x ₁ , x ₂ ,..., x _n );

Among them, R _7d and R _28d represent the strength of the filling body 7d and 28d; x ₁ , x ₂ ,..., x _n represent the proportion of all solid waste filling materials; K _28d represents the water resistance stability coefficient of the curing 28d filling body; f ₁ , f ₂ represents the relationship function between the strength of the filling body 7d and 28d and the amount of solid waste added; f ₃ represents the relationship function of the water resistance stability of the curing 28d filling body and the amount of solid waste added.

(4) Establish an optimization model for the proportion of all solid waste filling materials. Taking the cost of the filling material as the optimization goal, and taking the strength and water resistance stability of the cemented filling body as the constraints, an optimization model for the proportion of all-solid waste filling materials is established:

Optimization objective: MinC _T = Minf _c (x ₁ , x ₂ ,..., x _n ) (1)

Constraints: R _7d = f ₁ (x ₁ , x ₂ ,..., x _n )≥[R _7d ]

R _28d =f ₂ (x ₁ ,x ₂ ,...,x _n )≥[R _28d ] (2)

K _28d =f ₃ (x ₁ ,x ₂ ,...,x _n )≥[K _28d ]

Among them, C _T represents the total cost of the solid waste filling material, f _c (x ₁ , x ₂ ,..., x _n ) is the cost function of the solid waste filling material; [R _7d ], [R _28d ] represent the cemented filling body 7d , the design value of 28d strength; f ₁ , f ₂ represent the strength function of the 7d, 28d filling body; f ₃ represents the water resistance stability function of the curing 28d filling body; [K _28d ] represents the design value of the water resistance stability coefficient of the 28d filling body .

(5) Solve the optimization model of all solid waste filling material. Solve the optimization model for the proportion of the full solid waste filling material in step (4), thereby obtaining the optimal proportion of the filling material.

The invention proposes a method for optimizing the proportion of filling materials for all solid wastes with water resistance and stability for the application of low-quality solid wastes in large water mines. By establishing an optimization model for the proportion of all solid waste filling materials, the proportion of filling materials is optimized. Low-quality solid wastes include phosphogypsum, carbide slag, fly ash, copper tailings, and high-activity blast furnace slag micropowder. The three systems of total solid waste filling materials will be described below.

Example 1: Phosphogypsum-Slag Micropowder-Carbide Slag System

To optimize the ratio of all solid waste filling materials for the phosphogypsum-slag powder-carbide carbide slag system, the solid waste of the system is first dried and ground, and then the chemical composition analysis and particle size test are carried out. The chemical composition analysis results of phosphogypsum in the filling material of this system are shown in Table 1. The particle size distribution curve is shown in Figure 2.

Table 1: Analysis results of chemical composition of phosphogypsum

chemical composition P₂O₅ Fe₂O₃ Al₂O₃ MgO CaO SO₄^2- F acid insoluble content/% 1.47 0.48 0.36 2.44 28.6 49.07 0.87 10.17

The particle size distribution curve of the slag micropowder in the phosphogypsum-slag micropowder-carbide carbide slag system is shown in Figure 3. It can be seen that the content of -45μm fine particles in the slag micropowder accounts for 81.9%;

活性系数

The chemical composition of the slag powder is shown in Table 2, and the quality coefficient of the slag powder is shown in Table 2.

activity coefficient

Table 2: Analysis results of chemical composition of blast furnace slag micropowder

chemical composition CaO SiO₂ Al₂O₃ MgO SO₃ Fe₂O₃ content/% 43.51 30.68 14.03 7.35 1.32 0.72 chemical composition TiO₂ MnO K₂O Na₂O P₂O₅ other content/% 0.68 0.57 0.54 0.33 0.06 0.21

The microscopic surface morphology structure of phosphogypsum is shown in Figure 4, and the XRD pattern is shown in Figure 5.

In the phosphogypsum-slag powder-carbide slag system, calcium carbide slag is a low-quality waste residue with calcium hydroxide as the main component after the hydrolysis of calcium carbide to obtain acetylene gas. The main components are CaO, CaS, Ca ₃ N ₂ , Ca ₃ P ₂ , Ca ₂ Si, Ca ₃ As ₂ , Ca(OH) ₂ . The content of CaO reaches 87%. Also contains sulfide, phosphide and other toxic and harmful substances. Using calcium carbide slag as an alkali activator and phosphogypsum sulfate compound excitation to produce a water hardening reaction.

The proportions of phosphogypsum-slag powder-carbide carbide slag system filling materials are as follows: phosphogypsum 40%-65%, slag powder 15%-40%, carbide slag 10%-20%; - Test on the strength and water resistance stability of the backfill material of the slag micropowder-carbide carbide slag system. The test results are shown in Table 3.

Table 3: Test results of strength and water resistance of phosphogypsum-carbide slag-slag micropowder system backfill

Using the quadratic polynomial regression method, the test data of the cemented backfill strength and water resistance stability of the phosphogypsum-carbide slag-slag micropowder system were regressed, and the 7d and 28d strength of the backfill and the water resistance stability of the 28d backfill K _28d were established. The mathematical model is as follows:

R _7d = 5.93-0.104x ₁ -0.111x ₂ +0.000517x ₁ x ₁ +0.00110x ₁ x ₂ (1)

R _28d = 13.02-0.00175x ₁ x ₁ -0.00907x ₂ x ₂ (2)

K _28d = 1.08-8.39x ₁ +8.28x ₂ +0.084x ₁ x ₁ -0.081x ₂ x ₂ +0.084x ₁ x ₃ -0.083x ₂ x ₃ (3)

f _c = 43.87+2.39x ₃ -0.0037x ₂ x ₃

In the formula: x ₁ represents the content of phosphogypsum, %; x ₂ represents the content of carbide slag, %; x ₃ represents the content of slag fine powder, %. Establish a ratio optimization model of phosphogypsum-carbide slag-slag micropowder system:

Min f _c = Min(43.87+2.39x ₃ -0.0037x ₂ x ₃ ) (4)

1.08-8.39x ₁ +8.28x ₂ +0.084x ₁ x ₁ -0.081x ₂ x ₂ +0.084x ₁ x ₃ -0.083x ₂ x ₃ ≥0.85 (7)

Solving the optimization model of the total solid waste filling material ratio of the phosphogypsum-carbide slag-slag micropowder system by formulas (4)-(7), the optimal ratio of the total solid waste filling material is obtained: the content of phosphogypsum is 48%, the content of calcium carbide slag is 48% The amount of slag powder is 20%, and the amount of slag powder is 32%. The strengths of cemented filling bodies 7d and 28d are 0.93 MPa and 5.25 MPa, respectively. The water resistance stability coefficient of the filling body after curing for 28d is 0.86.

Example 2: Phosphogypsum-Slag Micropowder-Carbide Slag-Copper Separation Tailing System

To optimize the ratio of all solid waste filling materials in the phosphogypsum-slag micropowder-carbide slag-copper tailings system, the solid waste in the system is firstly dried and ground, as well as chemical composition analysis and particle size testing. The chemical composition of the phosphogypsum filling material of this system is shown in Table 4.

Table 4: Results of chemical composition of phosphogypsum in phosphogypsum-slag powder-carbide slag-copper tailings system

chemical composition P₂O₅ Fe₂O₃ Al₂O₃ MgO CaO SO₄^2- F acid insoluble content/% 1.76 0.48 0.28 2.44 30.64 53.52 0.45 6.67

活性系数

The particle size distribution curve of the slag micropowder of the phosphogypsum-slag micropowder-carbide slag-copper tailings system is shown in Figure 3. The slag micropowder-45μm fine particle content accounts for 81.9%; the chemical composition of the slag is shown in Table 5, and the quality coefficient

activity coefficient

Table 5: Chemical composition of slag in phosphogypsum-slag powder-carbide slag-copper tailings system

chemical composition CaO SiO₂ Al₂O₃ MgO SO₃ Fe₂O₃ content/% 43.51 30.68 14.03 7.35 1.32 0.72 chemical composition TiO₂ MnO K₂O Na₂O P₂O₅ other content/% 0.68 0.57 0.54 0.33 0.06 0.21

The microscopic surface morphology and structure of the phosphogypsum are shown in Figure 4, and the XRD pattern of the phosphogypsum is shown in Figure 5.

The main components of the calcium carbide slag in the phosphogypsum-slag powder-carbide slag-copper tailings system are CaO, CaS, Ca ₃ N ₂ , Ca ₃ P ₂ , Ca ₂ Si, Ca ₃ As ₂ , and Ca(OH) ₂ . The CaO content accounts for 87%.

The copper tailings in the phosphogypsum-slag powder-carbide slag-copper tailings system are low-quality solid wastes discharged after the copper-nickel slag is selected for copper and then iron (see Figure 6). The particle size distribution is shown in Figure 7.

Proportion range of phosphogypsum-slag powder-carbide carbide slag-copper tailings system full solid waste filling material: phosphogypsum 40%-50%, slag powder 25%-35%, carbide slag 10%-20%, copper dressing The tailings are 5%-20%. According to the ratio range of the system, the strength and water resistance stability tests of the cemented backfill are carried out. The test results are shown in Table 6.

Table 6: Test results of strength and water resistance of phosphogypsum-carbide slag-slag powder-copper tailings system backfill

Using quadratic polynomial regression analysis of test data, the mathematical model of cemented backfill 7d, 28d strength and 28d water resistance stability K _28d is established as follows:

R _7d = 1.76+0.35x ₁ -0.55x ₂ -0.4x ₃ -0.0034x ₁ x ₁ +0.014x ₂ x ₂ -0.004x ₃ x ₃ -0.05x ₁ x ₂ +0.01x ₁ x ₃ (8)

R _28d = 1.86-0.00184 x ₂ x ₂ (9)

K _28d = -30.5+2.19x ₁ -0.69x ₂ -0.021x ₁ x ₁ +0.019x ₂ x ₂ -0.0097x ₃ x ₃ +0.0025x ₄ x ₄ -0.013x ₁ x ₂ -0.0059x ₁ x ₄ ( 10)

A quadratic polynomial is used to regress the filling cost data to obtain the material cost function f _c :

f _c = 29.74+2.025x ₂ +0.014x ₁ x ₂ +0.021x ₃ x ₄ (11)

In the formula: x ₁ represents the content of phosphogypsum, %; x ₂ represents the content of slag micropowder, %, x ₃ represents the content of carbide slag, %, and x ₃ represents the content of copper tailings, %.

The material ratio optimization model of phosphogypsum-slag powder-carbide slag-copper tailings system was established:

_MinCT = Min(29.74+2.025x ₂ +0.014x ₁ x ₂ +0.021x ₃ x ₄ (12)

1.76+0.35x ₁ -0.55x ₂ -0.40x ₃ -0.0034x ₁ x ₁ +0.014x ₂ x ₂ -0.004x ₃ x ₃ -0.05x ₁ x ₂ +0.01x ₁ x ₃ ≥0.5 (13)

1.86-0.00184x ₂ x ₂ ≥2.5 (14)

-30.5+2.19x ₁ -0.69x ₂ -0.021x ₁ x ₁ +0.019x ₂ x ₂ -0.0097x ₃ x ₃ +0.0025x ₄ x ₄ -0.013x ₁ x ₂ -0.0059x ₁ x ₄ ≥0.85 (15 )

Solving formulas (12)-(15), the optimal model for the proportion of phosphogypsum-slag micropowder-carbide slag-copper tailings system for all-solid waste filling materials, the proportion of filling materials obtained is: the content of phosphogypsum is 46%, the content of calcium carbide slag is 46% 10% of slag powder, 32% of slag powder, and 12% of copper tailings. The strengths of cemented filling bodies 7d and 28d reached 0.67MPa and 3.80MPa, respectively. The water resistance stability coefficient of the 28d filling body reaches 0.92.

Example 3: Phosphogypsum-Slag Micropowder-Carbide Slag-Fly Ash System

The material ratio optimization method of phosphogypsum-slag micropowder-carbide slag-fly ash system, the solid waste in the system is dried, ground, chemical composition analysis and particle size test.

The chemical composition of phosphogypsum in the filling material of phosphogypsum-slag powder-carbide slag-fly ash system is shown in Table 7.

Table 7: Chemical Composition of Phosphogypsum in Phosphogypsum-Slag Micropowder-Carbide Slag-Fly Ash System

The particle size distribution curve of the slag micropowder of the phosphogypsum-slag micropowder-carbide slag-fly ash system is shown in Figure 3, and the slag micropowder-45μm fine particle content is 81.9%;

活性系数

The chemical composition of the slag is shown in Table 8, the quality coefficient

activity coefficient

Table 8: Chemical composition of slag in phosphogypsum-slag micropowder-carbide slag-fly ash system

chemical composition CaO SiO₂ Al₂O₃ MgO SO₃ Fe₂O₃ content/% 43.51 30.68 14.03 7.35 1.32 0.72 Element TiO₂ MnO K₂O Na₂O P₂O₅ other content/% 0.68 0.57 0.54 0.33 0.06 0.21

The microscopic surface morphology structure of the phosphogypsum is shown in Figure 4, and the XRD pattern of the phosphogypsum is shown in Figure 5.

The main components of calcium carbide slag in the phosphogypsum-slag micropowder-carbide slag-fly ash system are CaO, CaS, Ca ₃ N ₂ , Ca ₃ P ₂ , Ca ₂ Si, Ca ₃ As ₂ , and Ca(OH) ₂ . The CaO content accounts for 87%.

The chemical composition of fly ash in the phosphogypsum-slag micropowder-carbide slag-fly ash system is shown in Table 9, the XRD diffraction pattern is shown in Fig. 8, and the particle size distribution diagram is shown in Fig. 9.

Table 9: Chemical composition analysis results of fly ash from thermal power plants

chemical composition SiO₂ Al₂O₃ Fe₂O₃ CaO MgO SO₃ K₂O+Na₂O content/% 48.76 16.22 23.91 2.05 1.44 0.89 1.59

The ratio of phosphogypsum-slag powder-carbide slag-fly ash system full solid waste filling material range is: phosphogypsum 40%-50%, slag powder 25%-35%, carbide slag 10%-15%, pulverized coal Ash 5%-20%. According to the ratio range of the phosphogypsum-slag powder-carbide slag-fly ash system, the strength and water resistance stability tests of the backfill were carried out. The test results are shown in Table 10.

Table 10: Test results of strength and water resistance of phosphogypsum-carbide slag-slag powder-fly ash system backfill

Using the quadratic polynomial regression analysis method, the regression analysis was carried out on the test data of the backfill strength and water resistance stability of the phosphogypsum-slag powder-carbide slag-fly ash system. The mathematical model of the water stability coefficient K _28d is as follows:

R _7d = 40.2-0.51x ₁ -2.22x ₂ +0.66x ₃ +0.0086x ₁ x ₁ +0.051x ₂ x ₂ -0.020x ₃ x ₃ -0.012x ₁ x ₂ +0.009x ₁ x ₃ -0.021x ₂ x ₃ (16)

R _28d = -85.96+4.29x ₁ +0.20x ₂ -2.46x ₃ -0.053x ₁ x ₁ -0.01x ₂ x ₂ +0.03x ₃ x ₃ +0.01x ₁ x ₂ +0.035x ₁ x ₃ +0.0033x ₂ x ₃ (17)

K _28d = 44.96+0.16x ₁ -3.31x ₂ +0.052x ₁ x ₁ -0.0079x ₃ x ₃ -0.011x ₁ x ₄ +0.0038x ₂ x ₂ +0.015x ₂ x ₄ +0.0058x ₃ x ₄ (18 )

Using quadratic polynomial regression analysis method, the cost data of phosphogypsum-slag micropowder-carbide slag-fly ash system filling material cost data regression analysis, to establish the filling material cost model f _c :

f _c = 41.29 + 2.40x ₂ +0.0098x ₁ x ₄ (19)

In the formula: x ₁ represents phosphogypsum, %; x ₂ represents slag fine powder, %, x ₃ represents carbide slag, %, fly ash=100%-x ₁ -x ₂ -x ₃ .

Establish a material ratio optimization model of phosphogypsum-slag powder-carbide slag-fly ash system:

_MinCT = Min(41.29+2.40x ₂ +0.0098x ₁ x ₄ ) (20)

40.2-0.51x ₁ -2.22x ₂ +0.66x ₃ +0.0086x ₁ x ₁ +0.051x ₂ x ₂ -0.020x ₃ x ₃ ≥0.5 (21)

-85.96+4.29x ₁ +0.20x ₂ -2.46x ₃ -0.053x ₁ x ₁ -0.01x ₂ x ₂ +0.03x ₃ x ₃ +0.01x ₁ x ₂ +0.035x ₁ x ₃ +0.0033x ₂ x ₃ ≥2.5 (22)

44.96+0.16x ₁ -3.31x ₂ +0.052x ₁ x ₁ -0.0079x ₃ x ₃ -0.011x ₁ x ₄ +0.0038x ₂ x ₂ +0.015x ₂ x ₄ +0.0058x ₃ x ₄ ≥0.85 (23)

Solving formulas (20)-(23) for the optimal proportioning model of phosphogypsum-slag powder-carbide slag-fly ash system, the optimal proportions of filling materials are obtained: phosphogypsum 46%, calcium carbide slag 26%, slag powder 12%, Fly ash 16%. The strengths of the filling bodies 7d and 28d are 1.13 MPa and 3.50 MPa, respectively. The water resistance stability coefficient of the 28d filling body is 0.88.

Aiming at the water resistance stability requirements of the backfill body in safe production in Dashui mines and the water immersion weakening characteristics of the all-solid waste backfill body, the invention provides a method for optimizing the proportion of all-solid waste backfill materials. The key technology of the present invention is to optimize the proportion of solid waste filling materials by establishing an optimization model, so as to realize the optimal combination and synergistic effect of the proportions of various solid wastes, thereby preparing an all-solid waste filling material with water resistance and stability. A way has been explored for resource utilization of low-quality solid waste in backfill mining of Dashui mines.

A method for optimizing the proportion of all-solid waste filling materials with water resistance and stability in Dashui mines provided by the embodiments of the present application has been described in detail above. The description of the above embodiment is only used to help understand the method of the present application and its core idea; meanwhile, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific embodiment and the scope of application, In conclusion, the content of this specification should not be construed as a limitation on the present application.

As certain terms are used in the specification and claims to refer to particular components. It should be understood by those skilled in the art that hardware manufacturers may refer to the same component by different nouns. The present specification and claims do not use the difference in name as a way to distinguish components, but use the difference in function of the components as a criterion for distinguishing. As mentioned in the entire specification and claims, "comprising" and "including" are open-ended terms, so they should be interpreted as "including/including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range, and basically achieve the technical effect. Subsequent descriptions in the specification are preferred embodiments for implementing the present application. However, the descriptions are for the purpose of illustrating the general principles of the present application and are not intended to limit the scope of the present application. The scope of protection of this application should be determined by the appended claims.

It should also be noted that the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a commodity or system comprising a list of elements includes not only those elements, but also includes not explicitly listed other elements, or elements inherent to the commodity or system. Without further limitation, an element defined by the phrase "comprising a..." does not preclude the presence of additional identical elements in the article or system that includes the element.

It should be understood that the term "and/or" used in this document is only an association relationship to describe associated objects, indicating that there may be three kinds of relationships, for example, A and/or B, which may indicate that A exists alone, and A and B exist simultaneously. B, there are three cases of B alone. In addition, the character "/" in this document generally indicates that the related objects are an "or" relationship.

The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various various other combinations, modifications and environments, and can be modified within the scope of the concept of the application described herein, using the above teachings or skill or knowledge in the relevant field. However, modifications and changes made by those skilled in the art do not depart from the spirit and scope of the present application, and should all fall within the protection scope of the appended claims of the present application.

Claims (6)

1. a method for optimizing the proportioning of all solid waste filling materials with water resistance stability in Dashui mines, it is characterised in that the step of the method comprises: S1, dry and grind the solid waste material to obtain mixed powders with different ratios; the mixed powders include phosphogypsum and blast furnace slag; S2. Carry out the strength test and water resistance test of the filling body for all the mixed powders obtained in S1, and obtain the results of the filling body strength test and the water resistance performance test results of the mixed powders with different ratios; S3. According to the backfill strength test results and water resistance test results obtained in S2, establish a backfill strength mathematical model and a water resistance stability mathematical model; S4. Taking the cost of the filling material as the optimization objective, and taking the mathematical model of the strength of the backing body and the mathematical model of the water resistance stability obtained in S3 as the constraints, an optimization model for the proportion of all-solid waste filling materials is established; S5. Solve the optimization model of the proportion of all solid waste filling materials obtained in S4, and obtain the optimal proportion of all solid waste filling materials; The methods for obtaining the results of the water resistance performance test and the water resistance performance test include: preparing two groups of filling body test blocks, respectively placing them in water and a curing box for curing; testing the uniaxial compressive strength of the two groups of filling body test blocks, The ratio of the uniaxial compressive strength of the filling body test block under the two curing conditions is taken as the test result of the water resistance performance of the mixed powder; In step S3: The second-order polynomial was used to perform regression analysis on the strength test results of the backfill, and the mathematical model of the 7d and 28d strength of the cemented backfill was established; Using the quadratic polynomial to perform regression analysis on the results of the water resistance performance test, the mathematical model of the water resistance stability of the 28d backfill was established; The mathematical model of the strength of the cemented filling body 7d and 28d is: R _7d =f ₁ (x ₁ ,x ₂ ,...,x _n ), R _28d =f ₂ (x ₁ ,x ₂ ,...,x _n ); Among them, R _7d and R _28d represent the strength of the filling body 7d and 28d; x ₁ , x ₂ ,...,x _n represent the ratio of all solid waste filling materials; f ₁ and f ₂ represent the strength and solid waste of the filling body 7d and 28d. The relationship function of the amount of waste added; The mathematical model of water resistance stability is: K _28d = f ₃ (x ₁ , x ₂ ,...,x _n ) Among them, K _28d represents the water resistance stability coefficient of the curing 28d filling body, x ₁ , x ₂ ,...,x _n represents the proportion of all solid waste filling materials, f ₃ represents the water resistance stability coefficient of the 28d filling body and the solid waste The relationship function of the dosage; The all-solid waste filling material ratio optimization model described in step S4 includes: Optimization objective: MinC _T =Min f _c (x ₁ ,x ₂ ,...,x _n ); Constraints: R _7d =f ₁ (x ₁ ,x ₂ ,...,x _n )≥[R _7d ] R _28d =f ₂ (x ₁ ,x ₂ ,...,x _n )≥[R _28d ] K _28d =f ₃ (x ₁ ,x ₂ ,...,x _n )[K _28d ]; Among them, C _T represents the cost of all solid waste filling materials, and f _c (x ₁ ,x ₂ ,...,x _n ) is the cost function of filling materials; [R _7d ] and [R _28d ] represent the design values of the strength of the filling body 7d and 28d, and [K _28d ] represent the design value of the water resistance stability coefficient of the 28d filling body. 2 . The method for optimizing the proportion of all-solid waste filling materials with water resistance and stability in Dashui mines according to claim 1 , wherein the parameter requirements of the phosphogypsum include: P ₂ O ₅ ≤ 5%, moisture content ≤ 3%, MgO≤3% and specific surface area≥200m ² /kg. 3. The method for optimizing the proportion of all-solid waste filling materials with water resistance and stability in Dashui mines according to claim 1, wherein the parameter requirements of the blast furnace slag include: blast furnace slag fineness≤5% or specific surface area ≥420m ² /kg, quality coefficient ≥1.6, activity index ≥0.3 and moisture content <3%. 4. The method for optimizing the proportion of water-resistant and stable all-solid waste filling materials in Dashui mines according to claim 1, wherein the mixed powder also comprises calcium carbide slag, fly ash and copper selection tailings. one or more. 5. The method for optimizing the proportion of all-solid waste filling materials with water resistance and stability in Dashui mines according to claim 4, characterized in that the parameter requirements of the carbide slag, the fly ash and the copper tailings Including: moisture content <3% and specific surface area ≥300m ² /kg. 6. The method for optimizing the proportion of water-resistant and stable all-solid waste filling materials in Dashui mines according to claim 4, characterized in that, when the mixed powder comprises phosphogypsum, blast furnace slag and carbide slag, the mass of each component accounts for 30%. The ratio is: phosphogypsum 40%-65%, blast furnace slag 15%-40%, calcium carbide slag 10%-20%; When the mixed powder includes phosphogypsum, blast furnace slag, carbide slag and copper dressing tailings, the mass proportion of each component is: 40%-50% of phosphogypsum, 25%-35% of blast furnace slag, and 10%-15% of calcium carbide slag. %, copper tailings 5%-20%; When the mixed powder includes phosphogypsum, blast furnace slag, carbide slag and fly ash, the mass proportion of each component is: 40%-50% of phosphogypsum, 25%-35% of blast furnace slag, and 10%-15% of calcium carbide slag , fly ash 5%-20%.

Images