Phosphorus tailing-based sprayed concrete preparation method and application method thereof

Abstract

The invention discloses a preparation method and a use method of phosphate tailing-based sprayed concrete. The preparation method comprises the following steps: mixing phosphate tailings with cement to obtain a mixture; mixing water with an accelerator to obtain a mixed solution; and mixing the mixture with the mixed solution to obtain the phosphate tailing-based sprayed concrete. The technical problems that in an existing method for producing the building material through the phosphate tailings, the phosphate tailings are complex in component, all components of the phosphate tailings are difficult to effectively utilize, the production process is complex, and the cost is high are solved. According to the method, the sprayed concrete can be prepared from the phosphate tailings, the influence on the environment is reduced, meanwhile, the cost is reduced, the resource utilization efficiency is improved, and the method has very high economical efficiency and feasibility.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a method for preparing phosphorus tailings-based shotcrete and a method for using the same. Background Art

[0002] In the chemical industry, phosphate tailings are a common industrial solid waste. Phosphate tailings are obtained by flotation technology to concentrate low-grade phosphate ore. 2 O 5 The solid waste generated after phosphate ore beneficiation mainly comes from the beneficiation, processing and refining of phosphate ore. Phosphate tailings usually contain a large amount of silicon, aluminum, calcium, phosphorus and other elements, as well as a small amount of phosphorus, fluorine, radioactive elements, etc. For every 1.0 ton of phosphate ore selected, 0.44 tons of phosphate tailings will be generated. However, the excess phosphate tailings have not been effectively utilized, and most of them can only be disposed of in the form of yards or landfills, with a comprehensive utilization rate of less than 10%.

[0003] In the field of building materials and construction, shotcrete is a widely used engineering material, usually composed of coarse aggregate, fine aggregate, cement, water and chemical additives. Shotcrete has the characteristics of rapid solidification, high strength, good impermeability and durability, and is widely used in the construction of slope engineering, mining engineering, tunnel engineering and underground engineering.

[0004] Existing research has not combined phosphate tailings with shotcrete technology. Phosphorus tailings and shotcrete are two relatively independent concepts. In the prior art, phosphate tailings are usually treated by landfilling, stockpiling, etc., but this not only occupies a large amount of land resources, but also easily causes environmental pollution; secondly, the existing method of using phosphate tailings to produce building materials, although it can realize the partial resource utilization of phosphate tailings, there are still some problems, such as the complex composition of phosphate tailings, it is difficult to effectively utilize all its components, and the production process is complicated and the cost is high. In addition, the existing method for preparing shotcrete usually requires a large amount of coarse and fine aggregates and cement, which is costly. Therefore, developing a new method for preparing shotcrete using phosphate tailings is a problem that needs to be solved in this field at present, in order to realize the recycling and resource utilization of phosphate tailings and reduce the impact on the environment.

[0005] The patent document with announcement number CN113480206A discloses a method for preparing cement mineralizer and producing cement clinker using phosphate tailings. However, in this method, the mass ratio of cement mineralizer prepared using phosphate tailings to raw materials is 2 to 5:100, the amount of phosphate tailings used accounts for a small proportion, and cement clinker needs to be obtained by sintering raw materials, which cannot be prepared at the construction site.

[0006] The patent document with the announcement number CN110482920A discloses a method for purifying flotation phosphorus tailings and preparing concrete blocks, which uses alkaline calcium materials to adjust the pH of the flotation phosphorus tailings slurry, so that the water-soluble phosphorus forms insoluble substances and is fixed in the phosphorus tailings, and the phosphorus tailings are washed with the neutralized phosphorus tailings slurry filtrate to form insoluble substances for discharge, and the purified flotation tailings are mixed with cement, sand, gravel and other materials through stirring, vibration molding, curing and other processes to form ordinary concrete small blocks. However, this method is not suitable for use in the shotcrete process. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a method for preparing phosphate tailings-based shotcrete and a method for using the same.

[0008] The present invention is achieved through the following technical solutions.

[0009] The present invention provides a method for preparing phosphate tailings-based shotcrete, comprising the following steps:

[0010] S1: mixing phosphate tailings with cement to obtain a mixture;

[0011] S2: Mixing water and accelerating setting agent to obtain a mixed solution;

[0012] S3: mixing the mixed material with the mixed liquid to obtain phosphorus tailings-based shotcrete.

[0013] Preferably, the weight ratio of the phosphate tailings to cement is 40-60:15-30.

[0014] Preferably, the amount of water added is 25-50% of the total mass of the mixture, and the amount of the accelerating agent added is 3-8% of the cement content.

[0015] Preferably, in step S1, the phosphate tailings and cement are dry-mixed and the stirring time is 3 to 5 minutes.

[0016] Preferably, the content of particles with a particle size of less than 0.075 mm in the phosphate tailings is above 75%.

[0017] Preferably, the content of CaO in the phosphate tailings is ≤30%, 2 O 5 Content ≤ 10%, SiO 2 Content ≤ 15%, Al 2 O 3 The content of is ≤20%, and the content of MgO is ≤10%.

[0018] Preferably, the quick-setting agent is an alkali-free liquid quick-setting agent.

[0019] A method for using phosphate tailings-based shotcrete comprises the following steps:

[0020] S1: Load the dry mixture of phosphate tailings and cement into the sprayer, and use compressed air to press the dry aggregate into a suspended state in the hose and send it to the spray gun;

[0021] S2: Connect the water pipe of the sprayer to the container with the mixed liquid, mix the mixed material and the mixed liquid at the nozzle of the sprayer, and spray them onto the construction surface.

[0022] Preferably, the spraying pressure onto the construction surface is 0.5-2.0 MPa, and the spraying distance is 1-5 m.

[0023] Preferably, the thickness of the phosphate tailings-based shotcrete sprayed onto the construction surface is 5 to 20 cm.

[0024] The beneficial effects of the present invention are:

[0025] 1. Resource utilization: The present invention realizes the recycling and resource utilization of phosphate tailings by preparing shotcrete from phosphate tailings, effectively solves the problems of land occupation and environmental pollution caused by the accumulation of phosphate tailings, and helps to promote the comprehensive utilization of phosphate tailings, reduce environmental pollution, and realize the sustainable utilization of resources.

[0026] 2. Cost reduction: In the process of preparing shotcrete, the present invention can achieve shotcrete with high strength, good impermeability and durability by adding a small amount of cement and sand and gravel aggregates, which greatly reduces the preparation cost and improves the economic benefit.

[0027] 3. Simplified process: The preparation process of the present invention is simple, easy to operate, easy to implement, and conducive to popularization and application. Compared with the prior art, the present invention directly utilizes the original phosphorus tailings without the need for complex production processes such as dehydration, grinding and screening, thereby improving production efficiency and reducing production costs.

[0028] 4. Superior performance: The phosphate tailings shotcrete prepared by the present invention has the characteristics of good fluidity, rapid solidification, high strength and good anti-seepage performance. It is suitable for construction in the fields of mine support, tunnel engineering, underground engineering, etc., and has broader market application prospects.

[0029] 5. The present invention solves the technical problems in the existing method of using phosphorus tailings to produce building materials, that is, the phosphorus tailings have complex components, it is difficult to effectively utilize all of its components, and the production process is complex and the cost is high. Through the present invention, it is possible to use phosphorus tailings to prepare shotcrete, reduce the impact on the environment, reduce costs, and improve resource utilization efficiency, which has strong economy and feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a preparation and use flow chart of the present invention; DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0032] Embodiment 1:

[0033] like Figure 1 As shown, a method for preparing phosphate tailings-based shotcrete comprises the following steps:

[0034] S1: mixing phosphate tailings with cement to obtain a mixture;

[0035] S2: Mixing water and accelerating setting agent to obtain a mixed solution;

[0036] S3: mixing the mixed material with the mixed liquid to obtain phosphorus tailings-based shotcrete.

[0037] The weight ratio of the phosphate tailings to cement is 40:30.

[0038] The amount of water added is 25% of the total mass of the mixture, and the amount of the accelerating agent added is 3% of the cement content.

[0039] In the step S1, the phosphate tailings and cement are dry-mixed, and the mixing time is 3 to 5 minutes.

[0040] The content of particles with a particle size of less than 0.075 mm in the phosphate tailings is more than 75%.

[0041] The content of CaO in the phosphate tailings is 28%, 2 O 5 The content is 10%, SiO 2 The content of Al is 14%, 2 O 3 The content of Al is 20%, and the content of MgO is 8%.

[0042] The accelerator is the DS-6 alkali-free liquid accelerator sold by Guizhou Shiboshi Technology Co., Ltd.

[0043] The cement is grade 425 cement.

[0044] A method for using phosphate tailings-based shotcrete comprises the following steps:

[0045] S1: Load the dry mixture of phosphate tailings and cement into the sprayer, and use compressed air to press the dry aggregate into a suspended state in the hose and send it to the spray gun;

[0046] S2: Connect the water pipe of the sprayer to the container containing the mixed liquid, turn on the spray switch and the water pump switch, mix the mixed material and the mixed liquid at the nozzle of the sprayer, and spray them onto the construction surface to obtain a concrete layer;

[0047] S3: The concrete layer is cured and solidified in a natural environment for no less than 7 days. During the curing process, appropriate covering and moisturizing measures can be taken to speed up the hardening of the concrete.

[0048] The spraying pressure onto the construction surface is 0.5 MPa, and the spraying distance is 1.5 m to ensure the spraying effect and personnel safety; the spraying thickness of the phosphate tailings-based shotcrete is 5 cm to ensure that a concrete layer of sufficient strength can be formed.

[0049] Embodiment 2:

[0050] like Figure 1 As shown, a method for preparing phosphate tailings-based shotcrete comprises the following steps:

[0051] S1: mixing phosphate tailings with cement to obtain a mixture;

[0052] S2: Mixing water and accelerating setting agent to obtain a mixed solution;

[0053] S3: mixing the mixed material with the mixed liquid to obtain phosphorus tailings-based shotcrete.

[0054] The weight ratio of the phosphate tailings to cement is 60:15.

[0055] The amount of water added is 50% of the total mass of the mixture, and the amount of the accelerating agent added is 8% of the cement content.

[0056] In the step S1, the phosphate tailings and cement are dry-mixed, and the mixing time is 5 minutes.

[0057] The content of particles with a particle size of less than 0.075 mm in the phosphate tailings is more than 75%.

[0058] The content of CaO in the phosphate tailings is 25%, 2 O 5 The content of SiO is 9%, 2 The content of Al is 12%, 2 O 3 The content of Al is 16%, and the content of MgO is 10%.

[0059] The accelerator is the DS-6 alkali-free liquid accelerator sold by Guizhou Shiboshi Technology Co., Ltd.

[0060] The cement is grade 425 cement.

[0061] A method for using phosphate tailings-based shotcrete comprises the following steps:

[0062] S1: Load the dry mixture of phosphate tailings and cement into the sprayer, and use compressed air to press the dry aggregate into a suspended state in the hose and send it to the spray gun;

[0063] S2: Connect the water pipe of the sprayer to the container containing the mixed liquid, turn on the spray switch and the water pump switch, mix the mixed material and the mixed liquid at the nozzle of the sprayer, and spray them onto the construction surface to obtain a concrete layer;

[0064] S3: The concrete layer is cured and solidified in a natural environment for no less than 7 days. During the curing process, appropriate covering and moisturizing measures can be taken to speed up the hardening of the concrete.

[0065] The spraying pressure onto the construction surface is 2.0 MPa, and the spraying distance is 5 m to ensure the spraying effect and personnel safety; the spraying thickness of the phosphate tailings-based shotcrete is 20 cm to ensure that a concrete layer of sufficient strength can be formed.

[0066] Embodiment 3:

[0067] like Figure 1 As shown, a method for preparing phosphate tailings-based shotcrete comprises the following steps:

[0068] S1: mixing phosphate tailings with cement to obtain a mixture;

[0069] S2: Mixing water and accelerating setting agent to obtain a mixed solution;

[0070] S3: mixing the mixed material with the mixed liquid to obtain phosphorus tailings-based shotcrete.

[0071] The weight ratio of the phosphate tailings to cement is 50:22.

[0072] The amount of water added is 41% of the total mass of the mixture, and the amount of the accelerating agent added is 5% of the cement content.

[0073] In step S1, the phosphate tailings and cement are dry-mixed, and the mixing time is 4 minutes.

[0074] The content of particles with a particle size of less than 0.075 mm in the phosphate tailings is more than 75%.

[0075] The content of CaO in the phosphate tailings is 30%, 2 O 5 The content is 10%, SiO 2 The content of Al is 15%, 2 O 3 The content of Al is 19%, and the content of MgO is 10%.

[0076] The accelerating agent is the DS-6 type alkali-free liquid accelerating agent sold by Guizhou Stone Doctor Technology Co., Ltd.

[0077] The cement is grade 425 cement.

[0078] A method for using phosphate tailing-based shotcrete includes the following steps:

[0079] S1: Load the dry-mixed mixture of phosphate tailings and cement into a shotcreting machine, and use compressed air to make the dry aggregate in a suspended state in the hose and send it to the spray gun.

[0080] S2: Connect the water delivery pipe of the shotcreting machine to a container filled with a mixed liquid, turn on the spray switch and the water pump switch, so that the mixture and the mixed liquid are mixed at the nozzle of the shotcreting machine and sprayed onto the construction surface to obtain a concrete layer.

[0081] S3: The concrete layer is cured in the natural environment, and the curing time is not less than 7 days. During the curing process, appropriate covering and moisturizing measures can be taken to accelerate the hardening speed of the concrete.

[0082] The spraying pressure onto the construction surface is 1.6 MPa, and the spraying distance is 2.8 m to ensure the spraying effect and personnel safety; the spraying thickness of the phosphate tailing-based shotcrete is 12 cm to ensure that a concrete layer with sufficient strength can be formed.

[0083] Comparative Example 1:

[0084] A method for preparing and using shotcrete is the same as that in Example 3, except that the mixture obtained by dry-mixing phosphate tailings and cement is replaced with sand and gravel aggregate, and the mass ratio of sand to stone in the sand and gravel aggregate is 1:1.

[0085] For the shotcrete prepared in Examples 1-3 and Comparative Example 1, refer to the "Standard for Cement Mortar Fluidity Test GB / T 2419-2005", "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete GB / T 50082-2009", "Standard for Geotechnical Test Methods GB / T50123-2019", "Standard for Test Methods of Basic Properties of Building Mortar JGJ / T 70-2009", "GB / T

[0086] 17671-2021 Method for Testing the Strength of Cement Mortar" and "Technical Specification for Application of Shotcrete JGJ / T 372-2016" for performance testing. The test contents include the 7-day compressive strength and 28-day compressive strength when the designed strength is 5 MPa. The obtained results are shown in the following table.

[0087]

[0088] Through comparative tests, the working performance, durability, permeability and mechanical properties of the phosphate tailings-based shotcrete prepared in Examples 1-3 are not much different from those of the shotcrete prepared using existing materials, and all meet the requirements of the specifications.

Claims

1. A method for preparing phosphate tailings-based shotcrete, characterized in that: The following steps are involved: S1: mixing phosphate tailings with cement to obtain a mixture; S2: Mixing water and accelerating setting agent to obtain a mixed solution; S3: mixing the mixed material with the mixed liquid to obtain phosphorus tailings-based shotcrete.

2. A method for preparing phosphate tailings-based shotcrete according to claim 1, characterized in that: The weight ratio of the phosphate tailings to cement is 40-60:15-30.

3. A method for preparing phosphate tailings-based shotcrete according to claim 1, characterized in that: The amount of water added is 25-50% of the total mass of the mixture, and the amount of the accelerating agent added is 3-8% of the cement content.

4. A method for preparing phosphate tailings-based shotcrete as claimed in claim 1, characterized in that: In the step S1, the phosphate tailings and cement are dry-mixed, and the mixing time is 3 to 5 minutes.

5. A method for preparing phosphate tailings-based shotcrete according to claim 1, characterized in that: The content of particles with a particle size of less than 0.075 mm in the phosphate tailings is more than 75%.

6. A method for preparing phosphate tailings-based shotcrete according to claim 1, characterized in that: The content of CaO in the phosphate tailings is ≤30%, the content of P2O5 is ≤10%, the content of SiO2 is ≤15%, the content of Al2O3 is ≤20%, and the content of MgO is ≤10%.

7. A method for preparing phosphate tailings-based shotcrete according to claim 1, characterized in that: The quick-setting agent is an alkali-free liquid quick-setting agent.

8. A method for using the phosphorus tailings-based shotcrete according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Load the dry mixture of phosphate tailings and cement into the sprayer, and use compressed air to press the dry aggregate into a suspended state in the hose and send it to the spray gun; S2: Connect the water pipe of the sprayer to the container with the mixed liquid, mix the mixed material and the mixed liquid at the nozzle of the sprayer, and spray them onto the construction surface.

9. The method for using the phosphorus tailings-based shotcrete according to claim 8, characterized in that: The spraying pressure onto the construction surface is 0.5-2.0 MPa, and the spraying distance is 1-5 m.

10. The method for using the phosphorus tailings-based shotcrete according to claim 8, characterized in that: The thickness of the phosphate tailings-based shotcrete sprayed onto the construction surface is 5 to 20 cm.

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