Solidification method of solid waste

Abstract

The invention provides a solid waste curing method which comprises the following steps: S1, uniformly mixing phosphate tailings and fly ash to obtain a raw material body; s2, quantitative NaOH is measured and fully mixed with liquid water glass with the modulus of 3.2, and an alkaline exciting agent with the specific modulus is prepared; s3, uniformly mixing the quantitative raw material body with the alkaline activator to obtain polymer neat paste; s4, pouring the polymer neat paste into a mold, and placing the mold on a compaction table for compaction to obtain a sample; the preparation method has the beneficial effects that the polymer is successfully prepared by taking the phosphate tailings as a main raw material and taking the fly ash as a supplement and applying an alkali excitation method. Through detection, the polymer shows the excellent characteristics of high compressive strength and high mechanical property, and has wide application prospects and development potential in the fields of roadbed materials, tailing backfill materials and the like. Moreover, in the process of preparing the polymer, a large amount of phosphate tailings is consumed.

Description

Technical Field

[0001] This application belongs to the technical field of solid waste pollution prevention and control, and specifically relates to a solidification method for solid waste. Background Technique

[0002] Geopolymer is an inorganic gel material composed of a three-dimensional network structure formed by the polycondensation reaction of reactive silicon-aluminum raw materials. Compared with ordinary Portland cement, it has the advantages of high mechanical properties, strong stability, good flame retardant effect, and efficient solid encapsulation of heavy metal ions. Most of the raw materials of geopolymer are solid wastes such as coal gangue, tailings, and tailings sand, and the amount of "three wastes" generated during the preparation process is also very small, belonging to an environmentally friendly green material.

[0003] Most of the phosphorus tailings generated by ore dressing are stored in the tailings pond in the form of waste, and a small part of the phosphorus tailings is used for filling. The stored phosphorus tailings occupy a large amount of land resources, and are easily washed by rainwater, causing groundwater pollution, water eutrophication, and natural disasters such as landslides. It is particularly important to realize the comprehensive utilization of phosphorus tailings resources. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related technologies.

[0005] To solve the above problems, this application provides a solidification method for solid waste, including the following steps:

[0006] S1. Uniformly mix phosphorus tailings and fly ash to obtain a raw material body;

[0007] S2. Measure a certain amount of NaOH and fully mix it with liquid water glass with a modulus of 3.2 to prepare an alkaline activator with a specific modulus;

[0008] S3. Uniformly mix a certain amount of the raw material body and the alkaline activator to obtain polymer paste;

[0009] S4. Pour the polymer paste into a mold, and place the mold on a vibrating table to vibrate and compact to obtain a sample;

[0010] S5. Place the sample at a specific temperature for a preset time, demold the sample and place it in a curing box for curing to obtain a polymer;

[0011] S6. Detect the compressive strength of the obtained polymer.

[0012] Optionally, in the S2, the specific modulus is 1.0-1.4.

[0013] Optionally, in the step S1, the particle size of the phosphorus tailings is 0-67.31 μm, and the chemical composition percentage is CaO - 34.14%, MgO - 15.26%, SiO 2 - 5.28%, Al 2 O 3 - 0.49%, Fe 2 O 3 - 0.76%, P 2 O 5 - 7.67%;

[0014] The particle size of the fly ash is 0 - 52.401 μm, and the chemical composition percentage is SiO 2 - 45.10, Al 2 O 3 - 24.20%, CaO - 5.6%, TiO 2 - 2.77%, MgO - 2.17%, SO 3 - 2.10%, Fe 2 O 3 - 1.21%, MnO - 0.23%.

[0015] Optionally, in the step S3, a quantitative raw material body and the alkaline activator are uniformly mixed by stirring, and the stirring time is 10 - 15 min.

[0016] Optionally, in the step S4, the vibration time of the mold on the vibrating table is 3 - 4 min.

[0017] Optionally, in the step S5, the preset time is 24 h.

[0018] Optionally, in the step S5, the temperature inside the cured sample is 20 - 25 °C, and the humidity is 90%.

[0019] Beneficial effects

[0020] In the embodiments of the present invention, a solid waste curing method is provided. Using phosphorus tailings as the main raw material and fly ash as a supplement, a polymer is successfully prepared by means of alkali activation. After testing, the polymer exhibits excellent properties such as high compressive strength and high mechanical properties, and has broad application prospects and development potential in many fields such as subgrade materials and tailings backfill materials. Moreover, a large amount of phosphorus tailings is consumed in the process of preparing the polymer. It provides a key technical path for effectively solving the problem of bulk industrial solid waste pollution, effectively improves the comprehensive utilization rate of industrial solid waste, and is of great significance for realizing the coordinated development of environmental protection and efficient resource utilization. Brief description of the drawings

[0021] Figure 1This is a flowchart of the solid waste solidification method of the present invention. Detailed implementation manners

[0022] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0023] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0024] In the present application, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected to", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] The following describes the preferred embodiments of the present invention with reference to the drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0026] Combined with reference to Figure 1 As shown, according to an embodiment of the present application, a solid waste solidification method is provided, including the following steps:

[0027] S1. Uniformly mix phosphorus tailings and fly ash to obtain a raw material body;

[0028] Specifically, when preparing the raw material body, phosphate tailings and fly ash are mixed in a certain proportion. First, according to the experimental requirements, an appropriate amount of phosphate tailings and fly ash are accurately weighed. The weighed phosphate tailings and fly ash are poured into the same stirring container for stirring. During the stirring process, it is necessary to ensure that the materials are fully turned over, so that the phosphate tailings particles and fly ash are evenly distributed, avoiding local agglomeration or uneven mixing, and finally obtaining a raw material body with excellent performance; among them, the particle size of the phosphate tailings is 0-67.31 μm, and the chemical composition percentage is CaO - 34.14%, MgO - 15.26%, SiO 2 - 5.28%, Al 2 O 3 - 0.49%, Fe 2 O 3 - 0.76%, P 2 O 5 - 7.67%; the particle size of the fly ash is 0-52.401 μm, and the chemical composition percentage is SiO 2 - 45.10, Al 2 O 3 - 24.20%, CaO - 5.6%, TiO 2 - 2.77%, MgO - 2.17%, SO 3 - 2.10%, Fe 2 O 3 - 1.21%, MnO - 0.23%.

[0029] S2. Measure a certain amount of NaOH and mix it fully with liquid water glass with a modulus of 3.2 to prepare an alkaline activator with a specific modulus;

[0030] Specifically, when preparing the alkaline activator, first, a sufficient amount of water glass with an initial modulus of 3.2 should be prepared. The modulus of water glass has a significant impact on its performance. A higher modulus means a higher degree of silicate polymerization and relatively weaker alkalinity. To adjust it to the appropriate range, a certain amount of NaOH needs to be accurately measured. As a strong base, NaOH can break the silicate polymerization chain and reduce the modulus when mixed with water glass. During the addition process, continuous stirring is required to ensure full contact and reaction between the two. By precisely controlling the addition amount of NaOH, based on the chemical reaction stoichiometry and real-time modulus detection, the modulus of water glass is gradually adjusted to 1.0 - 1.4. Within this modulus range, the alkaline activator can exhibit excellent performance. On the one hand, it can more effectively activate the active components in the raw material body, accelerate the reaction rate, and improve the early strength; on the other hand, the optimized alkaline activator can make the internal structure of the polymer more dense, enhance the later durability and stability, and facilitate the subsequent preparation of high-performance polymer paste.

[0031] S3. Mix a certain amount of the raw material body and the alkaline activator evenly to obtain polymer paste;

[0032] Specifically, first weigh an appropriate amount of raw material, pour it into a clean glass, then accurately weigh water, strictly control the water-cement ratio to 0.17, and after sufficient mixing, weigh an alkaline activator according to 15% of the raw material, which can stimulate the active ingredients in the raw material, accelerate the reaction process, and improve the early strength and durability of the polymer slurry. Pour the weighed alkaline activator into the raw material, and continue stirring for 10-15 minutes to allow the alkaline activator to fully contact and react with the raw material, so that the components of the entire system are more evenly distributed. The final result is a polymer slurry with a certain viscosity.

[0033] S4, pouring the polymer slurry into a mold, and placing the mold on a vibration table and vibrating it to obtain a sample;

[0034] Specifically, after obtaining the polymer slurry with a certain viscosity, prepare a triple mold with a size of 40mm×40mm×40mm. Before using the mold, carefully apply a layer of oil on its inner wall. This step can effectively facilitate the subsequent demolding and prevent the polymer slurry from sticking to the mold. After the coating is completed, slowly pour the polymer slurry into the mold while stirring to ensure that the slurry evenly fills every corner of the mold. Next, place the mold with the slurry on the vibration table and vibrate for 3-4 minutes. The vibration can remove the bubbles inside the slurry and make it more compact. After the vibration is completed, use a ruler to scrape off the excess slurry along the edge of the mold to make the surface smooth. At this point, all operations of the polymer slurry from preparation to molding are completed.

[0035] S5, curing the sample at a specific temperature for a preset time, demolding the sample and placing it in a curing box for curing to obtain a polymer;

[0036] Specifically, then, wrap the mold tightly with plastic wrap, which can effectively prevent water evaporation and keep the humidity environment inside the pure slurry stable. After wrapping, place the mold at a specific temperature for 24 hours. Demolding operation is carried out after 24 hours, and the demolding process needs to be cautious to avoid damage to the formed pure slurry specimen. After demolding, place the specimen horizontally in a constant temperature and humidity curing box. The temperature in the curing box is set to 25°C and the humidity is 90%. Curing for different cycles (for example, 3 days, 7 days, 28 days, etc., the specific curing cycle is determined according to the purpose of the experiment). Through such different cycles of curing, the polymer pure slurry specimen is fully hydrated, and the strength and performance are continuously developed, and finally a polymer with stable performance is obtained.

[0037] S6. Conducting a compressive strength test on the obtained polymer.

[0038] Specifically, the obtained polymer is subjected to a compressive strength test to obtain a final test result.

[0039] Optionally, in the step S2, the specific number of membranes is 1.0 - 1.4.

[0040] Optionally, in the step S1, the particle size of the phosphorus tailings is 0 - 67.31 μm, and the chemical composition percentages are CaO - 34.14%, MgO - 15.26%, SiO 2 - 5.28%, Al 2 O 3 - 0.49%, Fe 2 O 3 - 0.76%, P 2 O 5 - 7.67%;

[0041] The particle size of the fly ash is 0 - 52.401 μm, and the chemical composition percentages are SiO 2 - 45.10, Al 2 O 3 - 24.20%, CaO - 5.6%, TiO 2 - 2.77%, MgO - 2.17%, SO 3 - 2.10%, Fe 2 O 3 - 1.21%, MnO - 0.23%.

[0042] Optionally, in the step S3, a quantitative amount of the raw material body is uniformly mixed with the alkaline activator by stirring, and the stirring time is 10 - 15 min.

[0043] Optionally, in the step S4, the vibration time of the mold on the vibrating table is 3 - 4 min.

[0044] Optionally, in the step S5, the preset time is 24 h.

[0045] Optionally, in the step S5, the temperature inside the cured sample is 20 - 25 °C, and the humidity is 90%.

[0046] Example 1

[0047] In the process of polymer preparation, first, weigh the phosphorus tailings and fly ash precisely to make their ratio such that the phosphorus tailings content is 60% and the fly ash content is 40%. After pouring the two into the same stirring container, stir them to ensure that the materials are fully agitated and evenly mixed, avoiding local agglomeration, so as to obtain a raw material body with excellent performance. Next, prepare the alkaline activator. Slowly add a certain amount of NaOH to sufficient water glass with an initial modulus of 3.2 while continuously stirring to promote their full reaction. By precisely controlling the addition amount of NaOH and based on the stoichiometric relationship of chemical reactions and real-time modulus detection, adjust the modulus of the water glass to 1.2. Subsequently, control the mixing of the raw material body and water to achieve a water-cement ratio of 0.17. Add 15% of the alkaline activator based on the raw material body to the uniformly mixed raw material body and continuously stir for 10 minutes to make them fully contact, thereby obtaining a polymer paste with a certain viscosity. Then, slowly pour the polymer paste into the mold while stirring, and then place the mold on a vibrating table and vibrate for 3 minutes to remove the internal air bubbles and make the paste more dense. After vibration, use a straightedge to scrape off the excess paste to make the surface flat. Immediately, tightly wrap the mold with plastic wrap and cure it in an environment at 80°C for 24 hours to accelerate the reaction process. After 24 hours, demold it and place it horizontally in a constant temperature and humidity curing box at a temperature of 25°C and a humidity of 90% for curing for 3 days, 7 days, and 28 days respectively. After curing, conduct a compressive strength test on the prepared polymer. The results show that the compressive strength of the polymer prepared under this condition reaches 33.2 MPa after curing for 3 days, 38.3 MPa after curing for 7 days, and 46.3 MPa after curing for 28 days. These data indicate that with the increase of the curing time, the compressive strength of the polymer steadily increases, and its performance meets the standard of fly ash Portland cement with a strength grade of 42.5R in "Common Portland Cement" (GB175 - 2007).

[0048] Example 2

[0049] In the process of preparing the polymer, first, the phosphorus tailings and fly ash are accurately weighed to make the proportion reach 70% for the phosphorus tailings content and 30% for the fly ash content. After pouring the two into the same stirring container, they are stirred to ensure that the materials are fully turned over and evenly mixed, avoiding local agglomeration, so as to obtain the raw material body. Then, the alkaline activator is prepared. A certain amount of NaOH is slowly added to sufficient water glass with an initial modulus of 3.2, while continuously stirring to promote the full reaction of the two. By precisely controlling the addition amount of NaOH and based on the stoichiometric relationship of the chemical reaction and real-time modulus detection, the modulus of the water glass is adjusted to 1.2. Subsequently, the raw material body is controlled to be mixed with water to achieve a water-cement ratio of 0.17, and 15% of the alkaline activator based on the raw material body is added to the uniformly mixed raw material body, and continuously stirred for 10 minutes to make the two fully contact, thereby obtaining a polymer paste with a certain viscosity. Then, the polymer paste is slowly poured into the mold while stirring, and the mold is placed on a vibrating table and vibrated for 3 minutes to remove the internal bubbles and make the paste more dense. After vibration, the excess paste is scraped off with a straightedge to make the surface flat. Immediately, the mold is tightly wrapped with plastic wrap and cured in an environment of 80°C for 24 hours to accelerate the reaction process. After 24 hours, the mold is demolded and placed horizontally in a constant temperature and humidity curing box at a temperature of 25°C and a humidity of 90% for curing for 3 days, 7 days, and 28 days respectively. After curing, the compressive strength of the prepared polymer is detected. The results show that the compressive strength of the polymer prepared under this condition reaches 25.4 MPa after curing for 3 days, 26.0 MPa after curing for 7 days, and 34.0 MPa after curing for 28 days. These data indicate that with the increase of the curing time, the compressive strength of the polymer steadily increases, and its performance meets the standard of fly ash Portland cement with a strength grade of 32.5R in "Common Portland Cement" (GB175 - 2007).

[0050] Example 3

[0051] In the process of polymer preparation, first, the phosphorus tailings and fly ash are accurately weighed to make their ratio reach 60% for the phosphorus tailings content and 40% for the fly ash content. After pouring the two into the same stirring container, they are stirred to ensure that the materials are fully turned over and evenly mixed, avoiding local agglomeration, so as to obtain a raw material body with excellent performance. Then, the alkaline activator is prepared. A certain amount of NaOH is slowly added to sufficient water glass with an initial modulus of 3.2, while continuous stirring is carried out to promote the full reaction of the two. By accurately controlling the addition amount of NaOH and based on the stoichiometric relationship of chemical reactions and real-time modulus detection, the modulus of the water glass is adjusted to 1.1. Subsequently, the raw material body is controlled to be mixed with water to achieve a water-cement ratio of 0.17, and 15% of the alkaline activator based on the raw material body is added to the uniformly mixed raw material body, and continuous stirring is carried out for 10 minutes to make the two fully contact, thereby obtaining a polymer paste with a certain viscosity. Then, the polymer paste is slowly poured into the mold while stirring, and then the mold is placed on a vibrating table and vibrated for 3 minutes to remove the internal bubbles and make the paste more dense. After vibration, the excess paste is scraped off with a straightedge to make the surface flat. Immediately afterwards, the mold is tightly wrapped with plastic wrap and cured in an environment of 80°C for 24 hours to accelerate the reaction process. After 24 hours, the mold is demolded, and the specimens are horizontally placed in a constant temperature and humidity curing box at a temperature of 25°C and a humidity of 90% and cured for 3 days, 7 days, and 28 days respectively. After curing, the compressive strength of the prepared polymer is detected. The results show that the compressive strength of the polymer prepared under this condition reaches 23.1 MPa after 3 days of curing, 29.5 MPa after 7 days of curing, and 36.1 MPa after 28 days of curing. These data indicate that with the increase of the curing time, the compressive strength of the polymer steadily increases, and its performance reaches the standard of fly ash Portland cement with a strength grade of 32.5R in "Common Portland Cement" (GB175-2007).

[0052] Through the detection of the polymer, it can be known that the polymer prepared by this method has high compressive strength and excellent mechanical properties, and has broad application prospects and development and utilization space in the fields of subgrade materials, tailings backfill materials, etc. At the same time, a large amount of phosphorus tailings are consumed in this preparation process, providing practical technical support for the realization of the assessment index of the comprehensive utilization rate of industrial solid waste in the comprehensive prevention and control of pollution from bulk industrial solid waste, promoting the transformation of phosphorus tailings from mainly storage to mainly utilization, and realizing the coordinated unity of environmental benefits, social benefits and economic benefits.

[0053] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application. The above is only the preferred implementation manner of the present application. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present application, several improvements and variations can still be made, and these improvements and variations should also be regarded as within the protection scope of the present application.

Claims

1. A method for solidifying solid waste, characterized in that: The following steps are involved: S1, uniformly mixing the phosphate tailings and fly ash to obtain a raw material; S2. Take a certain amount of NaOH and mix it with liquid water glass with a modulus of 3.2 to prepare an alkaline activator with a specific modulus; S3, uniformly mixing a certain amount of the raw material and the alkaline activator to obtain a polymer slurry; S4, pouring the polymer slurry into a mold, and placing the mold on a compaction table and compacting it to obtain a sample; S5, curing the sample at a specific temperature for a preset time, demolding the sample and placing it in a curing box for curing to obtain a polymer; S6. Conducting a compressive strength test on the obtained polymer.

2. The solid waste solidification method according to claim 1, characterized in that: In the S2, the specific film number is 1.0-1.

4.

3. The solid waste solidification method according to claim 1, characterized in that: In the S1, the particle size of the phosphate tailings is 0-67.31 μm, and the chemical composition percentage is CaO-34.14%, MgO-15.26%, SiO2-5.28%, Al2O3-0.49%, Fe2O3-0.76%, P2O5-7.67%; The fly ash particle size is 0-52.401 μm, and the chemical composition percentages are SiO2-45.10%, Al2O3-24.20%, CaO-5.6%, TiO2-2.77%, MgO-2.17%, SO3-2.10%, Fe2O3-1.21%, and MnO-0.23%.

4. The solid waste solidification method according to claim 1, characterized in that: In S3, a certain amount of the raw material and the alkaline activator are mixed uniformly by stirring for 10 to 15 minutes.

5. The solid waste solidification method according to claim 1, characterized in that: In S4, the mold is vibrated on the vibration table for 3-4 minutes.

6. The solid waste solidification method according to claim 1, characterized in that: In the step S5, the preset time is 24 hours.

7. The solid waste solidification method according to claim 1, characterized in that: In the step S5, the temperature in the curing box is 20-25° C. and the humidity is 90%.

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