Coal ash coupled tailing environment-friendly cementing material and preparation method thereof

Abstract

The invention provides a fly ash coupled tailing environment-friendly cementing material and a preparation method thereof.The method comprises the following steps that 1, raw materials including fly ash, tailings and a first acid solution are sequentially subjected to dissolution reaction and solid-liquid separation, and a first solid phase and a first liquid phase are obtained; 2) sequentially performing activation reaction and solid-liquid separation on raw materials comprising the first solid phase and a first alkali solution to obtain a second solid phase and a second liquid phase; (3) sequentially carrying out primary gelling reaction on raw materials comprising a second solid phase and a second acid solution, and washing to obtain a pre-gelling body; and 4) carrying out an activation reaction on raw materials including the pre-gelatinized body, a second alkali solution and an oxidizing agent, and stirring and forming to obtain the cementing material. The coal ash and the tailings are co-processed, the metal leaching amount of the tailings is effectively reduced, the curing effect is obvious, resource utilization is achieved, and environmental pollution is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial solid waste resource utilization, and in particular to a fly ash coupled tailings environmentally friendly gelling material and a preparation method thereof. Background Art

[0002] Fly ash, typically gray or gray-black in color, is one of the most abundant industrial solid wastes currently emitted in my country. Its accumulation not only consumes land resources but also poses a serious threat to the natural ecosystem. The chemical composition of fly ash is closely related to that of coal, primarily consisting of silicon dioxide, aluminum oxide, as well as ferric oxide, calcium oxide, and unburned carbon. Because fly ash contains a variety of usable elements (such as aluminum and silicon), it is a rich resource with great development value. Effectively recovering the useful substances in fly ash would contribute to the development of a circular and conservation-oriented economy while also reducing the damage to the natural ecosystem caused by mining.

[0003] In addition, with the development of the economy, the demand for mineral products has increased significantly, and the scale of mining development has also increased. The amount of beneficiation tailings produced will continue to increase, and the large amount of stockpiled tailings will cause many problems for the mining industry, the environment and the economy. For example: (1) The cost of mineral resources is serious. Since tailings contain not only useful components such as metal ores and non-metallic ores that can be reselected, but also the final tailings that cannot be reselected have many uses, the amount of useful components wasted in the tailings is quite considerable. (2) The stockpiling of tailings occupies a large amount of land and the stockpiling investment is huge. (3) Tailings have a great impact on the natural ecological environment, and the tailings components and residual beneficiation reagents have serious damage to the ecological environment, especially tailings containing heavy metals. Sulfides produce acidic water that further leaches heavy metals, and their loss will cause harm to the entire ecological environment.

[0004] Therefore, in order to make better resource utilization of solid wastes such as tailings and fly ash and realize the industrial production of tailings and fly ash-based materials, it is necessary to provide a preparation method of environmentally friendly materials based on the coupling of fly ash and tailings. Summary of the Invention

[0005] In order to solve the above problems in the background technology, the purpose of the present invention is to provide a fly ash coupled tailings environmentally friendly cementitious material and a preparation method thereof, which can coordinate the disposal of fly ash and tailings, effectively reduce the metal leaching amount of tailings, and have a significant solidification effect, so as to realize resource utilization and reduce environmental pollution.

[0006] In order to achieve one aspect of the above purpose, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a fly ash-coupled tailings environmentally friendly gelling material, comprising the following steps:

[0008] 1) subjecting raw materials including fly ash, tailings, and a first acid solution to a dissolution reaction and solid-liquid separation in sequence to obtain a first solid phase and a first liquid phase;

[0009] 2) subjecting the raw materials including the first solid phase and the first alkaline solution to activation reaction and solid-liquid separation in sequence to obtain a second solid phase and a second liquid phase;

[0010] 3) subjecting the raw materials including the second solid phase and the second acid solution to a preliminary gelling reaction in sequence, and washing to obtain a pre-gel;

[0011] 4) Activating the raw materials including the pre-gel, the second alkaline solution and the oxidant, stirring and molding to obtain a gel material.

[0012] Furthermore, the total content of heavy metals Pb, Zn, Cu, Mn, Co, and Ni in the tailings is not less than 500 mg / kg, the Si content is not less than 30%, the Ca content is less than 3%, and the Si content in the fly ash is not less than 40%; preferably, the particle size of the fly ash and tailings is ≤100 mesh.

[0013] Furthermore, in step 1), the first acid solution is a strong acid selected from one or more of sulfuric acid and nitric acid, with a concentration range of 0.5-8 mol / L.

[0014] Furthermore, in step 1), the liquid-to-solid ratio (ml / g) of the first acid solution to the fly ash and tailings is in the range of 2:1 or more, preferably 4:1-10:1, the dissolution reaction temperature is in the range of 50°C or more, and the reaction time is in the range of 2h-8h.

[0015] Furthermore, in step 2), the first alkaline solution is selected from one or more of sodium hydroxide and potassium hydroxide, and the concentration range is 10%-40%.

[0016] Furthermore, in step 2), the liquid-solid ratio (ml / g) of the first alkaline solution to the first solid phase is in the range of 5:1-20:1, the activation reaction temperature is in the range of 90°C-140°C, and the reaction time is in the range of 30min-2h.

[0017] Furthermore, in step 3), the second acid solution is an organic weak acid selected from one or more of acetic acid and citric acid, with a concentration range of 0.05-2 mol / L.

[0018] Furthermore, in step 3), the liquid-solid ratio (ml / g) of the second acid solution to the second solid phase is in the range of 5:1-20:1, the dissolution reaction temperature is in the range of 30-90° C., and the reaction time is in the range of 30 min-120 min.

[0019] Furthermore, in step 4), the second alkaline solution is selected from one or more of sodium hydroxide and potassium hydroxide, and the concentration range is 10-30%.

[0020] Furthermore, in step 4), the liquid-solid ratio (ml / g) of the second alkaline solution to the pregel is in the range of 2:1-20:1, the amount of the oxidant added is 1 / 10-1 / 40 of the solution ratio, the activation reaction temperature is in the range of 60°C-120°C, and the reaction time is in the range of 30min-150min.

[0021] Furthermore, in step 4), the conditions for stirring and molding to obtain the gelling material include: stirring speed of 100-600 r / min, stirring time of more than 10 minutes, adding into the mold after stirring, and steaming and curing molding time of 12 hours to 24 days.

[0022] Furthermore, the oxidant is selected from commercially available hydrogen peroxide with a concentration of 20%-30%, and a certain amount of aluminum oxide is added at the same time, and the mass ratio of the aluminum oxide added to the Si element in the fly ash is 0.4:1-1.2:1.

[0023] Furthermore, the method further comprises: washing and centrifuging the pregel and then performing the activation reaction described in step 4).

[0024] In a second aspect, the present invention proposes a fly ash coupled tailings environmentally friendly gelling material prepared by the above method.

[0025] In the present invention, the liquid-to-solid ratio is the ratio of liquid volume to solid mass (ml / g).

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The present invention provides an environmentally friendly fly ash-tailings-coupled cementitious material. The method first involves subjecting fly ash and tailings to a dissolution reaction with a first acid solution for a minimum duration. This dissolution reaction activates pores and removes surface metals, yielding a first solid phase. The first solid phase is then subjected to an activation reaction with a first alkaline solution to activate silicon, yielding a second solid phase. The second solid phase then undergoes a preliminary gelation reaction with a second acid solution to yield a pre-gel. This pre-gel is then subjected to an activation reaction with a second alkaline solution and an oxidant to achieve activation and oxidation, further activating the Si and Al elements. Finally, the pre-gel is stirred and the molding time is controlled to successfully produce the fly ash-tailings-coupled cementitious material. The resulting cementitious material effectively solidifies residual heavy metals in the tailings. This preparation method innovatively combines fly ash and tailings, effectively utilizing industrial waste through a multi-step, sequential reaction. This not only reduces environmental pollution but also provides a new, efficient, and economical approach for the preparation of environmentally friendly cementitious materials, promising promising applications.

[0028] Other features and advantages of the present invention will be described in detail through the following detailed description. DETAILED DESCRIPTION

[0029] The specific embodiments of the present invention are described in detail below. It should be understood that the following examples are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Various changes, modifications, substitutions, and variations made to these embodiments by those of ordinary skill in the art without departing from the principles and purpose of the present invention are intended to be included within the scope of protection of the present invention.

[0030] The endpoints of the ranges and any values ​​disclosed herein are not limited to the exact ranges or values, and these ranges or values ​​should be understood to include approximate ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0031] As analyzed in the background technology of the present invention, in order to coordinate the disposal of fly ash and tailings, effectively reduce the amount of metal leaching from the tailings, and achieve a significant solidification effect, so as to achieve resource utilization and reduce environmental pollution, the present invention provides a fly ash coupled tailings environmentally friendly cementitious material and a preparation method thereof, comprising the following steps:

[0032] 1) subjecting raw materials including fly ash, tailings, and a first acid solution to a dissolution reaction and solid-liquid separation in sequence to obtain a first solid phase and a first liquid phase;

[0033] 2) subjecting the raw materials including the first solid phase and the first alkaline solution to activation reaction and solid-liquid separation in sequence to obtain a second solid phase and a second liquid phase;

[0034] 3) subjecting the raw materials including the second solid phase and the second acid solution to a preliminary gelling reaction in sequence, and washing to obtain a pre-gel;

[0035] 4) Activating the raw materials including the pre-gel, the second alkaline solution and the oxidant, stirring and molding to obtain a gel material.

[0036] In the present invention, the first solid phase contains the main components of tailings and fly ash, the first liquid phase contains removed heavy metals and acid solution, the second solid phase contains silicon and other components after the main heavy metals are removed, and the second liquid phase contains some heavy metals and alkali solution.

[0037] The main reaction route in the present invention is a first acid dissolution reaction-a first base activation reaction-a second acid gelation reaction-a second base activation reaction. Following the above sequence can fully remove heavy metals. Failure to follow the above sequence will result in insufficient metal removal and unstable residual metals.

[0038] In the present invention, the total content of heavy metals Pb, Zn, Cu, Mn, Co, and Ni in the tailings is not less than 500 mg / kg, the Si content is not less than 30%, the Ca content is less than 3%, and the Si content in the fly ash is not less than 40%. The advantages of selecting tailings and fly ash with the above component contents are: they can effectively remove heavy metals and effectively utilize components such as Si and Ca in the tailings.

[0039] In some specific embodiments, the tailings are selected from non-ferrous metal tailings.

[0040] In some specific embodiments, in step 1), the fly ash and tailings have a particle size of ≤100 mesh. This particle size is advantageous in that it facilitates mixing and subsequent reactions. For example, the fly ash or tailings are sieved and ball-milled to meet the above particle size requirements.

[0041] In some specific embodiments, the first acid solution is a strong acid selected from one or more of sulfuric acid and nitric acid, with a concentration ranging from 0.5 to 8 mol / L.

[0042] In some specific embodiments, in step 1), the liquid-to-solid ratio (ml / g) of the first acid solution to the fly ash and tailings is in the range of 2:1 or more, preferably 4:1-10:1, the dissolution reaction temperature is in the range of 50°C-180°C, and the reaction time is in the range of 2h-8h.

[0043] In step 1), the first acid dissolution reaction is preferably carried out under the above conditions, which can better activate the pore size and remove the surface metal.

[0044] In some specific embodiments, in step 2), the first alkaline solution is selected from one or more of sodium hydroxide and potassium hydroxide, and the concentration range is 10%-40%.

[0045] In some specific embodiments, in step 2), the liquid-to-solid ratio (ml / g) of the first alkaline solution to the first solid phase ranges from 5:1 to 20:1, the activation reaction temperature ranges from 90°C to 140°C, and the reaction time ranges from 30 min to 2 h.

[0046] In step 2), it is preferred to carry out the first alkali activation reaction under the above conditions, which can better activate the silicon and promote the subsequent gelation reaction.

[0047] In some specific embodiments, in step 3), the second acid solution is an organic weak acid selected from one or more of acetic acid and citric acid, with a concentration range of 0.05-2 mol / L.

[0048] In some specific embodiments, in step 3), the liquid-solid ratio (ml / g) of the second acid solution to the second solid phase is in the range of 5:1-20:1, the dissolution reaction temperature is in the range of 30-90°C, and the reaction time is in the range of 30 min-120 min.

[0049] In step 3), it is preferred to carry out a second preliminary gelation reaction under the above conditions, which can better promote the gelation reaction.

[0050] In some specific embodiments, in step 4), the second alkaline solution is selected from one or more of sodium hydroxide and potassium hydroxide, and the concentration range is 10-30%.

[0051] In some specific embodiments, in step 4), the liquid-to-solid ratio (ml / g) of the second alkaline solution to the pre-gel is in the range of 2:1-20:1, the solid-to-liquid ratio (g / ml) of the added oxidant to the total solution is in the range of 1 / 10-1 / 40, the activation reaction temperature is in the range of 60°C-120°C, and the reaction time is in the range of 30 min-150 min.

[0052] In step 4), it is preferred to carry out a second alkaline activation reaction under the above conditions to reactivate Si and Al, so that more Si forms a gel material.

[0053] In some specific embodiments, in step 4), the conditions for stirring and molding to obtain the gelling material include: stirring speed of 100-600 r / min, stirring time of more than 10 min, adding into the mold after stirring, and steaming and curing molding time of 12 h-24 d.

[0054] In some specific embodiments, the oxidant is selected from commercially available hydrogen peroxide with a concentration of 20%-30%, and a certain amount of alumina is added. The mass ratio of the alumina added to the Si element in the fly ash is 0.4:1-1.2:1, and illustratively, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, etc. The simultaneous addition of the oxidant and alumina during the second alkaline activation reaction has the following effects: the oxidant promotes the reconversion of some residual heavy metals (higher valence states are more easily solidified), reducing the leaching rate after gelation, while also increasing the microstructure pore size, and the alumina promotes a better gelation reaction, improving the overall strength.

[0055] In some specific embodiments, the method further comprises: washing the pre-gel and centrifuging it before performing the activation reaction in step 4). Exemplarily, the third solid phase is washed with ethanol and then centrifuged.

[0056] In the present invention, solid-liquid separation can be performed by conventional methods in the art, such as filtration, centrifugation, etc.

[0057] In the present invention, the types of the first acid solution and the second acid solution may be different. The first acid solution is mainly used to separate heavy metals, and the second acid solution is used for acidification after alkalization. The concentrations of the first alkaline solution and the second alkaline solution may be different. For example, the concentration of the second alkaline solution is lower than that of the first alkaline solution. The first alkaline solution is used to remove some residual heavy metals and activate silicon and aluminum in tailings and fly ash. The second alkaline solution is mainly used for activation and microscopic improvement, that is, to promote a more delicate gelation process and smaller and more uniform particles.

[0058] Secondly, the present invention proposes an environmentally friendly fly ash-coupled tailings cementitious material prepared by the above method. The present invention makes full use of solid waste to prepare cementitious materials, effectively removes most of the heavy metals in existing tailings, and effectively solidifies the heavy metals in the cementitious materials.

[0059] The technical solution of the present invention will be further described in detail below with reference to embodiments.

[0060] 1. Test method:

[0061] The test methods or reference standards for performance indicators are as follows:

[0062] Metal removal rate: ICP measures the metal content in the substance before and after the reaction and calculates the removal rate.

[0063] Metal leaching rate: Acid solution with a pH of 5.6 was used for reaction for 2 hours to examine the proportion of the content in the liquid after leaching in the overall curing cementitious material. The content during curing was determined after digestion.

[0064] The strength test is carried out using a universal testing machine.

[0065] 2. Source of raw materials:

[0066] Tailings from nonferrous metal smelting

[0067] Fly ash in electric field

[0068] Example 1

[0069] The fly ash comes from a power plant in Inner Mongolia. Its main components are SiO2 (54.38%), Al2O3 (3.45%), and CaO (2.41%). The tailings come from a waste copper tailing in Baise, Guangxi. The total content of heavy metals Pb, Zn, Cu, Mn, Co, and Ni is 11.45%, the Si content is 46.70%, and the Ca content is 6.44%.

[0070] First, fly ash and tailings are preliminarily screened and ball-milled to obtain a mixture with a particle size of less than 100 mesh. Then, nitric acid is added to the mixture for reaction at a reaction temperature of 60°C, a nitric acid concentration of 2 mol / L, a liquid-solid ratio of 6:1, and a reaction time of 4 h. The first solid phase and the first liquid phase are obtained by filtration. The first solid phase is then mixed with a 30% sodium hydroxide solution for activation reaction for 1 h at a reaction temperature of 120°C and a liquid-solid ratio of 10:1. The second solid phase and the second liquid phase are obtained by filtration. The mixture was mixed with 100ml / L acetic acid and reacted for 1 hour at 60°C, with a liquid-to-solid ratio of 10:1. After washing, a pre-gel was obtained. The pre-gel was then activated with a 10% sodium hydroxide solution, commercially available 20% hydrogen peroxide, and Al2O3 for 2 hours at 90°C. The liquid-to-solid ratio of the sodium hydroxide solution to the pre-gel was 10:1, the solid-to-liquid ratio of the hydrogen peroxide to the total solution was 1 / 20, and the mass ratio of the alumina to the Si element in the fly ash was 0.6:1. The mixture was then stirred and shaped (at a speed of 300 rpm for 1 hour). After stirring, the mixture was added to a mold and steam-cured for 18 hours to obtain a gelled material.

[0071] Example 2

[0072] The difference from Example 1 is that some reaction temperatures and times are different, specifically: the first acid reaction temperature is 90°C, the reaction time is 2h, the first alkali activation temperature is 140°C, the reaction time is 30min, the second acid reaction temperature is 90°C, the reaction time is 30min, and the second alkali activation temperature is 120°C, and the reaction time is 30min.

[0073] Example 3

[0074] The difference from Example 1 is that some reaction temperatures and times are different, specifically: the first acid reaction temperature is 50°C, the reaction time is 8 hours, the first alkali activation temperature is 90°C, the reaction time is 2 hours, the second acid reaction temperature is 30°C, the reaction time is 2 hours, and the second alkali activation temperature is 60°C, and the reaction time is 2.5 hours.

[0075] Example 4

[0076] The difference from Example 1 is that some concentration conditions are different, specifically: the first acid solution is 8 mol / L nitric acid, the first alkaline solution is 40% sodium hydroxide solution, the second acid solution is 2 mol / L acetic acid, and the second alkaline solution is 15% sodium hydroxide solution.

[0077] Example 5

[0078] The difference from Example 1 is that some concentration conditions are different, specifically: the first acid solution is 0.5 mol / L sulfuric acid, the first alkali solution is 20% sodium hydroxide solution, the second acid solution is 0.05 mol / L citric acid, and the second alkali solution is 10% sodium hydroxide solution.

[0079] Example 6

[0080] The difference from Example 1 is that some liquid-solid ratios are different, specifically: the liquid-solid ratio of the first acid reaction is 10:1, the liquid-solid ratio of the first alkali activation is 20:1, the liquid-solid ratio of the second acid reaction is 20:1, the liquid-solid ratio of the second alkali activation is 20:1, the amount of hydrogen peroxide added is 1 / 10 of the total solution ratio, and the mass ratio of alumina addition to Si element in fly ash is 1.2:1.

[0081] Example 7

[0082] The difference from Example 1 is that some liquid-solid ratios are different, specifically: the liquid-solid ratio of the first acid reaction is 4:1, the liquid-solid ratio of the first alkali activation is 5:1, the liquid-solid ratio of the second acid reaction is 5:1, the liquid-solid ratio of the second alkali activation is 2:1, the amount of hydrogen peroxide added is 1 / 40 of the total solution ratio, and the mass ratio of alumina addition to Si element in fly ash is 0.4:1.

[0083] Example 8

[0084] The difference from Example 1 is that no aluminum oxide is added during the second alkali activation reaction.

[0085] Example 9

[0086] The difference from Example 1 is that the first acid solution and the second acid solution are the same, both containing 2 mol / L nitric acid.

[0087] Example 10

[0088] The difference from Example 1 is that the first alkaline solution and the second alkaline solution have the same concentration, both of which are sodium hydroxide solutions with a concentration of 30%.

[0089] Comparative Example 1

[0090] The first acid reaction was not performed, and the rest was the same as in Example 1.

[0091] Comparative Example 2

[0092] The first alkali reaction was not performed, and the rest was the same as in Example 2.

[0093] Comparative Example 3

[0094] The order of the acid reaction and the base reaction is changed, and the specific order is: the first base activation reaction-the first acid dissolution reaction-the second acid gelation reaction-the second base activation reaction.

[0095] The properties of the gelling material products obtained in the examples of the present invention and the comparative examples are shown in Table 1 below.

[0096] Table 1

[0097]

[0098]

[0099] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. Those skilled in the art will appreciate that, based on the teachings of this specification, modifications or adjustments may be made to the present invention. Such modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A method for preparing fly ash coupled tailings environmentally friendly gelling material, characterized in that: The steps include: 1) subjecting raw materials including fly ash, tailings, and a first acid solution to a dissolution reaction and solid-liquid separation in sequence to obtain a first solid phase and a first liquid phase; 2) subjecting the raw materials including the first solid phase and the first alkaline solution to activation reaction and solid-liquid separation in sequence to obtain a second solid phase and a second liquid phase; 3) subjecting the raw materials including the second solid phase and the second acid solution to a preliminary gelling reaction in sequence, and washing to obtain a pre-gel; 4) Activating the raw materials including the pre-gel, the second alkaline solution and the oxidant, stirring and molding to obtain a gel material.

2. The method for preparing fly ash coupled tailings environmentally friendly gelling material according to claim 1, characterized in that: The total content of heavy metals Pb, Zn, Cu, Mn, Co, and Ni in the tailings is not less than 500 mg / kg, the Si content is not less than 30%, the Ca content is less than 3%, and the Si content in the fly ash is not less than 40%; preferably, the particle size of the fly ash and tailings is ≤100 mesh.

3. The method for preparing fly ash coupled tailings environmentally friendly gelling material according to claim 1 or 2, characterized in that: In step 1), the first acid solution is a strong acid selected from one or more of sulfuric acid and nitric acid, with a concentration range of 0.5-8 mol / L; and / or, In step 1), the liquid-solid ratio of the first acid solution to the fly ash and tailings is in the range of 2:1 or more, preferably 4:1-10:1, the dissolution reaction temperature is in the range of 50°C or more, and the reaction time is in the range of 2h-8h.

4. The method for preparing the fly ash coupled tailings environmentally friendly gelling material according to any one of claims 1 to 3, characterized in that: In step 2), the first alkaline solution is selected from one or more of sodium hydroxide and potassium hydroxide, with a concentration range of 10%-40%; and / or, In step 2), the liquid-solid ratio of the first alkaline solution to the first solid phase is in the range of 5:1-20:1, the activation reaction temperature is in the range of 90° C.-140° C., and the reaction time is in the range of 30 min-2 h.

5. The method for preparing the fly ash coupled tailings environmentally friendly gelling material according to any one of claims 1 to 4, characterized in that: In step 3), the second acid solution is an organic weak acid selected from one or more of acetic acid and citric acid, with a concentration range of 0.05-2 mol / L; and / or, In step 3), the liquid-solid ratio of the second acid solution to the second solid phase is in the range of 5:1-20:1, the dissolution reaction temperature is in the range of 30-90° C., and the reaction time is in the range of 30 min-120 min.

6. The method for preparing the fly ash coupled tailings environmentally friendly gelling material according to any one of claims 1 to 5, characterized in that: In step 4), the second alkaline solution is selected from one or more of sodium hydroxide and potassium hydroxide, with a concentration range of 10-30%; and / or, In step 4), the liquid-solid ratio of the second alkaline solution to the pregel is in the range of 2:1-20:1, the amount of the oxidant added is 1 / 10-1 / 40 of the solution ratio, the activation reaction temperature is in the range of 60°C-120°C, and the reaction time is in the range of 30min-150min.

7. The method for preparing the fly ash coupled tailings environmentally friendly gelling material according to any one of claims 1 to 6, characterized in that: In step 4), the conditions for stirring and molding to obtain the gelling material include: stirring speed of 100-600 r / min, stirring time of more than 10 minutes, adding into the mold after stirring, and steaming and curing molding time of 12 hours to 24 days.

8. The method for preparing the fly ash coupled tailings environmentally friendly gelling material according to any one of claims 1 to 7, characterized in that: The oxidant is selected from commercially available hydrogen peroxide with a concentration of 20%-30%, and a certain amount of aluminum oxide is added at the same time. The mass ratio of the aluminum oxide added to the Si element in the fly ash is 0.4:1-1.2:

1.

9. The method for preparing the fly ash coupled tailings environmentally friendly gelling material according to any one of claims 1 to 8, characterized in that: The method further comprises: washing the pregel, centrifuging it, and then performing the activation reaction described in step 4).

10. Fly ash coupled tailings environmentally friendly gelled material prepared by the method according to any one of claims 1 to 9.

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